Messerschmitt-Bf-109-F-K-Development-Testing-Production

Book Design by Ian Robertson. Copyright © 1999 by Willy Radinger & Wolfgang Otto. Library of Congress Catalog Number: 99-066588 All rights reserved. No part of this work may be reproduced or used in any forms or by any means - graphic, electronic or mechanical, including photocopying or information storage and retrieval systems - without written permission from the copyright holder. Printed in China. ISBN: 0-7643-1023-2 We are interested in hearing from authors with book ideas on related topics. Published by Schiffer Publishing Ltd. 4880 Lower Valley Road Atglen, PA 19310 Phone: (610) 593-1777 FAX: (610) 593-2002

In Europe, Schiffer books are distributed by: Bushwood Books 6 Marksbury Road Kew Gardens Surrey TW9 4JF

Book Design by Ian Robertson. Copyright © 1999 by Willy Radinger & Wolfgang Otto. Library of Congress Catalog Number: 99-066588 All rights reserved. No part of this work may be reproduced or used in any forms or by any means - graphic, electronic or mechanical, including photocopying or information storage and retrieval systems - without written permission from the copyright holder. Printed in China. ISBN: 0-7643-1023-2 We are interested in hearing from authors with book ideas on related topics. Published by Schiffer Publishing Ltd. 4880 Lower Valley Road Atglen, PA 19310 Phone: (610) 593-1777 FAX: (610) 593-2002

In Europe, Schiffer books are distributed by: Bushwood Books 6 Marksbury Road Kew Gardens Surrey TW9 4JF

Contents

6 Dedication 7 Foreword 8 Introduction 14 Bf 109 F-1 and F-2 16 High speed trials trials 19 Bf 109 F-4 20 Testing of underwing armament 23 The Bf 109 Gustav series 33 The Bf 109 H high-altitude fighter 35 Bf 109 K 39 Bf 109 L 40 Me 109 Z/Me 609 42 Preliminary experiments for for the the Me 209 43 The Messerschmitt Regensburg factory, aircraft production Bf 109 G 50 Color section 65 Photo section 151 Trials with 660 x 150 wheels

Dedication

I was associated with the Bf 109 from the first stroke of the pen until (he test flights to determine its terminal diving speed. And this is how it happened: after my final examination as a machine construction engineer in 1931 and my subsequent employment in a textile machine factory, in 1934 I moved to the Bayerische Flugzeugwerke at Augsburg-Haunstetten. There I was initially employed in the design bureau, "wing department." under the direction of Dipl.-Ing. Robert Prause. It was there that I first came into contact with the Bf 109. which was then being worked on under Project Number P 1034. Among other things I designed the wing cutouts for the retractable main undercarriage. Then from 1937 I was active as group leader in the preparation bureau, where I was involved exclusively with the development of the Messerschmitt variable-pitch propeller (Me P 6, Me P 7, Me P 2). From October 1937 up to and including June 1938 I earned my military pilot's license at the "Flight Practice Station Munich-Oberwiesenfeld." Back to Messerschmitt — the BFW GmbH became the Messerschmitt AG in

1938. At first I continued working on the variable-pitch propellers, but I also conducted individual and endurance trials with these. Because of this the management moved me to the flight test department as an engineer-pilot. Since I had amassed a large number of hours testing propellers, virtually all of the flight tests associated with the development of this type were given to me. Through these many and varied missions I came into intimate contact with the Bf 109 and its variants. Approximately 80% of all my flights were in the Bf 109. As well. I made similar test flights with the Bf  108 (propeller), Bf 110, Me 210, Me 309, Me 410, and toward the end of the war also in the twin-engined Me 262 jet. I remember one test flight, which will be the subject of its own chapter, especially well: determining the terminal dive velocity of the Bf 109 (G-series). Carrying out this task was the high point of my flying activities in general, and with the Bf 109 in particular. I wish this Bf 109 book many readers, especially younger ones who have grown up in the "jet age," so that they might gain some idea of what "propeller flying" was like back then.

Foreword

The first volume on the early versions of the legendary Bf 109 has proved very popular with readers. Now the second volume on the Bf 109 F to K plus several special developments up to the preliminary experiments for the Me 209 record-breaking machine and the Me 309. Messersehmitt's last propeller-driven fighter, is ready. This volume, too. concentrates on the technical aspects and testing of this remarkable aircraft. First several comments on type designation: since this aircraft was created by the Bayerischen Flugzeugwerke, it was designated the Bf 109. In 1938 the Bayerischen Flugzeugwerke became the Messerschmitt AG, however, the earlier designation continued to be widely used. However, the designation Me 109 also came into use. including in official documents, and it became very popular, especially outside Germany. For reasons of simplicity, in this book all series are identified as Bf 109. while the subsequent new developments are designated Me 209 and Me 309. The Bf 109 F to K were the most potent versions of this successful standard  Luftwaffe fighter. Few other fighters re-

years and were built in such a plethora of  variants, and the development potential of  the basic Bf 109 concept of 1935 is astonishing. But, as the Allies introduced newer, more potent fighters during the course of  the Second World War the limits of the Bf  109 became increasingly apparent. Nevertheless, it must be acknowledged that Willy Messerschmitt had created a groundbreaking design in the Bf 109. The Bf 109 is one of the most interesting and important aircraft in aviation history. This is underlined by the fact that several air forces, including those of Czechoslovakia. Spain. and Israel, used the Bf 109 with great success in the postwar period. Co-author of this volume is Herr Wolfgang Otto, who carefully evaluated the extensive original sources and documents. My thanks also go to Herr Dieter Herwig. who made available many photographs and technical material. This book is enriched — as was the first volume — by the outstanding drawings of Günter Sengfelder. In selecting the photos and proof-reading the book I was again able to rely on the support of Hanfried Schliephake, whom I would like to thank most sincerely at this point.

Introduction

Bf 109 Bf 109 F to K The Messerschmitt Bf 109 in its many versions and prototypes from "Friedrich" to "Konrad." The Messerschmitt Bf 109 is one of  the most significant designs produced by the German aviation industry. Designed by Willy Messerschmitt, its basic design was adapted to accept engines with outputs of 600 to 2,000 H.P. during its production life and achieved speeds from 450 kph to 720kph.

Bf 109 F-0

List of Variants Organized according to Type Compared to the Bf 109 E, the Bf 109 F was much improved in terms of aerodynamics. To achieve this the entire aircraft, including the wing, was redesigned.

Bf 109 F-01 V21 D-IFKQ; CE + BN Werk-Nr. 5602 Bf 109 F-02 V22 D-IRRQ; CE + BO Werk-Nr. 1800 Bf 109 F-03 V23 CE + BP Werk-Nr. 5603 Bf 109 F-04 V24 VK+AB Werk-Nr. 5604

10 pre-production machines Motor: DB 601 N 2 MG 17,1 MG FF/M (motor cannon) Armament: FuG VIIa R/T Radio equipment: Supercharger air intake of "Emil" variant. Werknummer blocks from 5605 to 5620, all built at Regensburg.

Bf 109 F-2/B

Fighter-bomber version of the F-2 Motor: DB 601 N Armament: 2 MG 17,1 MG 151/15 (motor cannon) Radio equipment: FuG VIIa ETC 250 bomb rack 

Bf 109 F-2/Z

Surviving specification from 18 September 1941 Motor: DB 601 N Armament: 2 MG 17,1 MG 151/15 {motor cannon) Radio equipment: FuG VIIa GM 1 system installed

Bf 109 F-2/trop Surviving specification DB 601 N 1,175 H.P. for takeoff at 2,600 rpm Motor: Armament: 2 MG 17, 1 MG 15 1/15 (motor cannon) Radio equipment: FuG VIIa Sand filter in front of supercharger air intake. Tropical equipment such as rifle, rations, water, flare pistol Bf 109 F-3

Bf 109 F-4

Bf 109 F-4/B

Project only Motor: Armament: Radio equipment:

DB 601 E, 1,350 H.P. for takeoff  2 MG 17,1 MG 151/15 (motor cannon) FuG VIIa

Fighter Motor: Armament: Radio equipment:

DB 601 E, 1,350 H.P. for takeoff  2 MG 17,1 MG 151/20 (motor cannon) FuG VIIa

Fighter-bomber equipment Motor: DB 601 E, 1,350 H.P. for takeoff  Armament: 2 MG 17,1 MG 151/20 (motor cannon) Radio equipment: FuG VIIa

Bf 109 F-4/trop Fighter Motor: Armament: Radio equipment:

DB 601 E, 1,350 H.P. for takeoff  2 MG 17,1 MG 151/20 (motor cannon) FuG VIIa Sand filter in front of supercharger air intake.

Bf 109 F-4/R1 Bomber destroyer with underwing armament

(1 MG 151/20 beneath each wing) DB 601 E Motor: 1,350 H.P. for takeoff  Armament: 2 MG 17,1 MG 151/20 (motor cannon) Radio equipment: FuG VIIa Bf 109 F-4/R6 ETC rack for 295-l drop tank or 1 SC 250 bomb or with

ER 4 adapter 4 SC 50 bombs Motor: 1,350 H.P. for takeoff  DB 601 E Armament: 2 MG 17, 1 MG 151/20 (motor cannon) Radio equipment: FuG VIIa Bf 109 F-4/B

Reconnaissance version, existed only as prototype Motor: 1,350 for takeoff  DB 601 E Armament: 2 MG 17 Radio equipment: FuG VIIa Rb 20/30 mounted in fuselage

Bf 109 F-6

Reconnaissance version of the F-4, existed only as prototype Motor: 1,350 H.P. for takeoff  DB 601 E Armament: none Radio equipment: FuG VIIa Rb 20/30, Rb 50/30, Rb 75/30 mounted in fuselage behind the cockpit. The only existing "F-6" was Galland's personal machine with additional armament of 2 x MG/FF

Bf 109 G-0

VJ + WA

Bf 109

Light fighter with pressurized cockpit, data sheet from 8 March 1943 DB 605 A Motor: Armament: 2 MG 17 and 1 MG 151/20 Radio equipment: FuG VIIa + XXV

G-1

12 prototypes

Bf 109 G-1/R2 Light fighter with pressurized cockpit, data sheet from 8 March 1943 DB 605 A Motor: Armament: 2 MG 17 and 1 MG 151/20 Radio equipment: FuG VIIa

No underwing armament, no head or back armor, no light metal armor, no protected tanks, no bombs or drop tank 

Bf 109 G-2

Light fighter without pressurized cockpit, data sheet from 8 March 1943 Motor: DB 605 A Armament: 2 MG 17 and 1 MG 151 /20 Radio equipment: FuG VIIa Equipped weight: 2520 kg

Bf 109 G-2/R2 Reconnaissance aircraft with Rb 50/30, data sheet from 8 March 1943

Motor: Armament: Radio equipment: Equipped weight:

DB 605 A

2 MG 17 and I MG 151/20 FuG 16Z 2619 kg

Bf 109 G-3

Light fighter with pressurized cockpit, data sheet from 8 March 1943 Motor: DB 605 A Armament: 2 MG 17 and 1 MG 151 /20 Radio equipment: FuG 16Z Equipped weight: 25 45 kg Built in small numbers (50 examples)

Bf 109 G-4

Light fighter without pressurized cockpit, data sheet from 8 March 1943 Motor: DB 605 A Armament: 2 MG 17 and 1 MG 151/20 Radio equipment: FuG 16Z Equipped weight: 25 85 kg

Bf 109 G-4/R2 Reconnaissance aircraft with RB 50/30 no pressurized cockpit data sheet from 8 March 1943 Motor: DB 605 A 2 MG 17 and 1 MG 151/20 Armament: FuG 16Z Radio equipment:

2695 kg Equipped weight: 1 x 300-l drop tank  Bf 109 G-4/R3 Armed reconnaissance aircraft with Rb 50/30, no pressurized cockpit, data sheet from 8/3/43 DB 605 A Motor: 1 MG 151/20 Armament: Radio equipment: FuG 16Z

Equipped weight:

2 595 kg

Bf 109 G-4/U1 Light fighter with braking propeller, data sheet from 8 March 1943 DB 605 A Motor:

Armament: Radio equipment: Equipped weight:

2 MG 17 and 1 MG 151/20 FuG 16Z 2585 kg P6 braking propeller and steerable tailwheel for braked landings

Bf 109 G-4/U3 Tactical reconnaissance aircraft without pressurized cockpit, data sheet from 8 March 1943 Motor: DB 605 A

Armament: Radio equipment: Equipped weight:

Bf 109 G-5

none FuG 17 2695 kg With 2 x Rb 12.5/7x9 cameras

Light tighter with pressurized cockpit; converted from G-6, data sheet from 8 March 1943 Motor: DB 605 A Armament: 2 MG 131 and 1 MG 151/20 Radio equipment: FuG 16Z Equipped weight: 26 00 kg

Bf 109 G-5/U2 Light fighter with pressurized cockpit. data sheet from 8 March 1943 Motor: DB 605 A + GM 1 system

Armament: Radio equipment: Equipped weight:

Bf 109 G-6

2 MG 131 and 1 MG 151/20 FuG 16Z 26 00 kg as per G-5

Light fighter without pressurized cockpit, data sheet from 8 March 1943 Motor: DB 605 A Armament: 2 MG 17 and 1 MG 151/20 Radio equipment: FuG 16Z Equipped weight: 2600 kg

Bf 109 G-6/R2 Reconnaissance aircraft with Rb 50/30, data sheet from 8 March 1943

Bf 109 G-6/R6 Heavy fighter with underwing MG 151/20 armament Motor: DB 605 A 2 MG 131 and 1 MG 151/20 Armament: Radio equipment: FuG 16Z

Equipped weight:

2610kg 2 x MG 151/20 in underwing gondolas

Bf 109 G-6/U1 Light fighter with braking propeller. data sheet from 8 March 1943 Motor: DB 605 A 2 MG 17 and 1 MG 151/20 Armament: Radio equipment: FuG 16Z

Equipped weight:

2600 kg with P6 braking propeller and steerable tailwheel for braked landings

Bf 109 G-6/U3 Tactical reconnaissance aircraft without pressurized cockpit, data sheet from 8 March 1943 Motor: DB 605 A

Armament: 2 MG 17 and 1 MG 151/20 Radio equipment: FuG 16Z Equipped weight: 2695 with 2 x Rb 12.5/7 x 9 cameras Bf 109 G-8

Light fighter without pressurized cockpit, data sheet from 8 March 1943 Motor: DB 605 A Armament: none Radio equipment: FuG 16Z Equipped weight: 2600 kg (as G-6/U3 but new-build aircraft)

Bf 109 G-10

Light fighter without pressurized cockpit DB 605 AS/D/D-2/DC/DB Motor: 2MG 131 and 1 MG 151/20, in some cases MK 108 Armament: FuG 25 Radio equipment: 2600 kg or greater, depending on equipment Equipped weight:

Bf 109 G-12

Two-seat training aircraft, conversions of single-seat machines Motor: DB 605 A/AS and others usually removed Armament:

Bf 109 F-1 and F-2

Compared to the earlier Bf 109 E, the Bf 109 F was much improved aerodynamically. The entire engine section was redesigned. The propeller spinner was enlarged and now blended smoothly into the entirely new engine cowling. Including spinner, hub. blades, and blade mounts, the threeblade VDM 9-11207 propeller used for the Bf 109 F-1 and F-2 weighed 138 kg. This propeller underwent further development, resulting in broader blades and a reduced diameter of 3 meters from the F-4 version. Furthermore, the entire wing was redesigned, the most obvious change being the new elliptical wingtips. The wing radiators were shallower and set farther back on the wing. The split flaps located behind the radiators were thermostatically controlled. As before, dihedral was 6° 32'. The second mean chord was 1 732 mm. The entire aerodynamic win area was 16 m2 with the landing flaps accounting for 2 x 0.522 m 2, the radiator flaps 2 x 0.4 m2 and the leading edge slats 2 x 0.311 m2. The surface area of  the ailerons was 2 x 0.387 m2. The undercarriage used VDM 8-278705 oil-damped oleos, each filled with 1.1

pennage attachment points. These were necessary because of tail nutter at high speeds, which usually resulted in structural failure. Power plant was the DB 601 N. which, with a displacement of 33.91 and a compression ratio of 1 : 8.2/8.5 (left/right), developed a maximum output of 1,175 H.P. Maximum revolutions for takeoff/emergency power were 2600 for a maximum of  three minutes at a boost pressure of 1.35 ata. Resulting fuel consumption was 215 to 225 g/PSh. Reduction gearing was 1:1.55. The Bf 109 F-1 weighed 2 0 1 5 kg empty, all-up weight in the fighter role was 2762 kg. in the fighter-bomber role with 1 x 250 kg bomb 3 041 kg. and in the fighter role with a 295-1 drop tank 3 026 kg. The empty weight of the Bf 109 F-2 was exactly the same as that of the Bf 109 F-1. All-up weight in the fighter role was 2,795 kg, and in the fighter-bomber role with 1 x 250 kg bomb 3073 kg. These weights were applicable for Load Class H4. For the fighter role only, 2820 kg was the maximum allowable gross weight for Load Class 5. For all other operational roles the maximum allowable gross weight was 3100 kg for Load Class H4. 2

of 750 kph, as this would overstress the airframe. This was not always possible in air combat, since no altitude-compensating airspeed indicator was installed, and therefore the true airspeed based on height could not be determined exactly. As a result, there were repeated crashes not due to enemy action. As a result of demands from the frontline units, trials were resumed to determine the aircraft's maximum diving speed. Armament was limited to two MG 17 machine-guns synchronized to fire through

the propeller disc and one unsynchronized MG 151/20 firing through the propeller hub. This "light" total armament came under much criticism, especially from Adolf  Galland. The result was a so-called special conversion with an additional MG/FF cannon in each wing, similar to the installation used in the Bf 109 E-3. This machine was supposedly designated the F-6/U. In terms of handling characteristics the Bf 109 F was probably the most capable version of  the Bf 109.

High-Speed Trials

Initial high-speed trials were carried out by the E-Stelle Rechlin, by Heinrich Beauvais, among others. Later, after protests by Ernst Udet in June 1941 (two letters to Messerschmitt personally), these trials were handed back to the Messerschmitt company's test pilots. This was probably due to the prevailing opinion in the RLM that the manufacturer should determine an aircraft's maximum speed. An accident on 17 July 1938 involving Dr. Jodlbauer (vertical crash) and the near crash of Heinrich Baeuvais in early 1941 undoubtedly played a part in this decision. At first Messerschmitl shelved this theme and nothing happened. The existing do-not-exceed speed of Bf 109 variants to date was in the area of 750 kph at all heights. But after the front-line units experienced an increase in accidents, for example, 20 within a two-month period, the investigation into maximum speed had to be resumed. From Willy Messerschmitt came the personal message: "The terminal diving speed of the Bf 109 is to be determined." Therefore, from January to March 1943 socalled "high-speed stress analysis experiments" were carried out. These experi-

An ejection seat was installed, and later aileron deflection was reduced to 50 percent of normal. The machine was subsequently brought to the flight test department for installation of the necessary instrumentation. This included an automatic camera for photographing the instrument panel and two ASKANIA recorders for airspeed and altitude. The first factory test flights now took place. The following is Lukas Schmid's description of his experiences: "On 29 January all was ready, it was time to carry out the first diving flight. Karl Bauer thought that, having already carried out the factory test flights, that I should also begin the next phase. During the first flights I climbed to an altitude of 7 000 to 8 000 meters. At the very outset it proved impossible to trim the horizontal stabilizer for pull-out. It turned out that the grease used to lubricate the horizontal stabilizer adjusting jack could not withstand the cold and froze in temperatures of -30 to -40 degrees. This was surely the cause of many of  the reported accidents. Cold-proof grease was immediately specified for the frontline units. With the stabilizer trim now in order. 1 conducted a test flight to find a stabilizer

also received no bonus for these risky flights. Such bonuses were standard. For example, I received 3,000 Reichsmarks for a diving flight in a Bf 109 with wooden tail assembly to 850 kph and a 6 g pull-out. Hermann Wurster received 10.000 Reichsmarks for the first flight in the Bf 110. At a

time when a bread roll cost 3 Pfennigs, that was a lot of money." As a result of the lessons learned in these trials the entire vertical tail, including the rudder, was heightened by 135 mm. Both metal and wooden versions of the larger vertical fin and rudder were introduced.

Bf 109 F-4

The next variant, the Bf 109 F-4, entered service in June 1941. It used the revised VDM 9-12010 three-blade propeller, whose diameter had been reduced to 3 meters. Total weight, including blades, blade mounts, and spinner was 132.6 kg. Externally the F-4 was similar to the F-2, however, a new Daimler-Benz engine using Pz.Art.Rgt. BR fuel was installed. This was the DB 601 E which produced 1,350 H.P. for takeoff or emergency power at 2,700 rpm at 1.42 ata. Output was initially restricted to 1,200 H.P. at 2,500 rpm. During production changes were made to the supercharger air intake. This was made larger in diameter and more teardrop shaped. The fighter's empty weight rose to 2086 kg. Gross weight was 2860

kg. The highest permissible gross weight in Load Class H5 was 2870 kg. For the extended-range version only Load Class H4 at 3123 kg was allowable. The GM-1 system was installed in the Bf 109 F-4/Z. This system increased engine output above the engine's rated altitude. This increase in performance was achieved by injecting so-called laughing gas (oxygen carrier) prior to the supercharger. As a result, a short-term performance increase could be achieved for a maximum of ten minutes. The system was installed in the wing between nose ribs 6 and 8, The fluid was contained either in eight so-called LUTZ bottles or in two circular tanks. Weight of the fluid was either 34 or 42 kg. Total weight of the system was 46 and 75 kg.

Testing of Underwing Armament

The weak basic armament of the Bf  109 made it necessary to increase firepower for the anti-bomber role. One Bf 109 F-4 was therefore equipped with Rüstsätze (equipment sets). Bad weather prevented the machine from being ferried to Tarnewitz for firing trials, however. Consequently, the equipment sets had to be sent there by rail. They were then installed on Werknummer  7449. The first static firing trials also produced the first problems, such as belts breaking. After modifications

to the drum and ammunition feed, as well as the installation of a guide tray on the feed side of the weapon, it performed satisfactorily on the test stand. When installed in the aircraft, however, new problems arose. With the left weapon the belt kinked before reaching the weapon, while with the right the empty belt failed to disintegrate. These problems were eliminated after modifications to the feed chute. The first air firing trials were carried out on 24 March 1942. During the course of these

Testing of Underwing Armament Air firing with 2 x MG 151/20 W.Nr. 13149 Dale:

Flight No Ammo load

Left weapon L R belt jam after 60 shots

Right weapon

28/5/42

1

135/135

29/5/42

2

30/5/42

Remarks

135/135

empty belt jam after 80 shots

normal

left spent belt chute modified

3

135/135

belt kinked

normal

left belt feed reset

30/5/42

4

135/135

normal

normal

30/5/42

5

135/135

normal

normal

31/5/42

6

135/135

normal

normal

31/5/42

7

135/135

normal

normal

31/5/42

8

135/135

normal

double load after 95 shots

normal

trails new problems arose which at first could not be identified. Sixty flights were required to identify the cause of the irregular stoppages, namely failure of the empty belts to disintegrate. The end of the belt hanging from the ejection chute was seized by the slipstream and pulled so forcefully from the weapon that it was no longer able to function properly. A horizontal extension was therefore applied to the spent belt ejector chute. As a result of this arrangement the empty belt could no longer be immediately seized by the slipstream and was better able to disintegrate. During the course of subsequent testing at Rechlin four aircraft were fitted with these modifications. Of a total of 27 air firing tests, 16 were completed with no stoppages of the left weapon and 17 with none of the right weapon. On the basis of  these results the aircraft were ferried to Wiener-Neustadt for conversion to produc-

tion standard and introduction of the changes into production. The four aircraft were converted during the period from 11 to 16 May 1942. Since the unit was about to be transferred to the front, air firing trials could only be carried out with one service aircraft. The modifications were subsequently applied to Werknummer  13149 ( E-Stelle Tarnewitz) , and leather flaps were installed on the spent belt and shell chutes to keep out sand and dust. The flaps were closed on the ground during takeoff and landing and were only opened during firing by the spent shell casings or belt links. After being ferried to Tarnewitz. Werknummer  13149 was used for firing trials with the MG 151/20 in various flight altitudes. A minor modification to the spent belt chute near the weapon almost completely eliminated the jamming of spent belts, which was still a problem, and the system was deemed reliable enough for installation.

Air firing with 2 x MG 151/15 Date:

Flight no.

Ammo load

Left weapon

Right weapon

Remarks

05/6/42

1

135/135

belt jammed

normal

flight aborted after 12 shots

05/6/42

2

100/100

spent belt blockage

normal

05/6/42

3

100/100

normal

normal

05/6/42

4

100/100

gun stoppage after 60 shots

normal

05/6/42

5

100/100

normal

normal

12/6/42

6

100/100

belt jammed

normal

The installation of a continuous belt rack in the drum in place of the previous cartridge holder spring made loading much easier and ensured a problem-free ammunition feed. Further problems arose during trials with 15-mm ammunition, for example, jamming of the ammunition in the drum on account of its smaller diameter, caused by the limited radius of the ammunition belt. The problem was eliminated by loading just 100 rounds per drum and taking particular care in installation. (The drum had to be shaken to prevent the ammunition from piling up.)

At a range of 100 m with 21 rounds fired, the shot pattern of the MG 151/20 was 60 x 39 cm for the left weapon and 48 x 49 cm for me right weapon. The final phase of testing was cold trials at minus 60 degrees. Problems were again encountered, for example, belts breaking, which were attributable to roughness of the drum. Following modifications (drum opening enlarged, inner drum wall thinned, etc.) and checking with a tolerance belt the weapon functioned satisfactorily. As a result, it was determined that: "The MG 151/  20 wing gondola armament performs satisfactorily."

The Bf 109 Gustav Series

The G-series, or Gustav, was a further development of the F-series. It seemed that all development possibilities had already been exhausted with the Bf 109 F. Then, at the end of December 1941, the new DB 605 A became available. This power plant was first installed in the G-1, while the Bf  109 G-0 pre-production series was powered by the DB 601 E. Designed in 1940, the DB 605 was a logical development of the DB 605 A 601 E. The most significant difference was an increase in displacement from 33.9 liters to 35.7 liters through boring out the cylinders. plus an increase in compression from 7.2 to 7.5. The resulting performance of the DB 605 A was 1475 H P. for takeoff at 1.42 atmospheres of boost. The initial installation of this engine produced some cooling problems, which resulted in the first of the so-called "bulges" which were to become synonymous with the Gustav. These were intake scoops to provide cooling air for the ejector exhausts and spark plugs. The scoops were installed on both sides of the engine cowling and were riveted to the metal skinning over the oil tank. Much larger bulges appeared later, the

lems with the pressurized cockpit made series production impossible at that time, however, and this version was built in several small batches. Production began at Regensburg in November 1941. Twenty machines were also built by Erla (Leipzig). The standard power plant was the DB 605 A using B4 (87 octane) fuel. The engine's compression ratio was 1 : 7.3/7.5. Takeoff and emergency power of  1,475 H.P. was achieved with 1.42 ata of  boost at 2,800 rpm. This output was initially banned by VT-Anw.Nr.2206 and was not reinstated until 8 June 1943 when DaimlerBenz issued a technical directive. Gearing ratio was 1 : 1.685. Engine weight was 700kg plus 3 percent. The main undercarriage used engine cowling wheels with channel rims for the 650 x 150 tires. Until December 1942 (when the G-4 was introduced) the tailwheel was fitted with an EC flat rim with a 290 x 110 tire. The propeller was a three-blade VDM 9-12087 A variable-pitch type with a diameter of 3 meters. Pitch control was either "electro-mechanical"" (automatic) or "manual-electric" using a thumb-switch on the throttle lever.

Original Extract: Flight Performance Altitude

Climb speed

Time lo climb

Climb rate

km

Max. speed True Indicated kph kph

kph

min./sec.

m/sec

0 1 2 3 4 5 6 7 8 9 10 11 12

525 54 4 563 58 3 602 622 642 649 64 8 64 3 630 609 55 5

28 0 28 0 28 0 28 0 28 0 28 0 28 0 28 0 27 5 27 0 265 26 0 255

52 5 51 7 51 0 50 2 49 2 482 47 0 452 42 4 39 8 367 33 2 28 0

0/47 1/35 2/24 3/16 4/11 5/14 6/23 7/46 9/36 11/54 15/41 24/02

21 21 21 19.8 18.6 17.4 15.8 13.3 10.9 8.3 6. 0 3.5 1.0

The performance figures shown are based on battle and climb power, or 2.600 rpm, 1.3 ata of boost. At present the DB 605 A is not cleared for takeoff and emer gency power. For effect of bombs, tanks and underwing weapons on speed see range table. Maxi mum boost altitude at full throttle, horizont al flight Max imu m boost altitude in clim b Takeoff run to height of 20 m, norma l Takeoff run to heigh t of 20 m, with bo mb Landi ng run from height of 20 m, normal braki ng

Bf 109 G-3

Only fifty examples of the G-3 were built at Regensburg during the period from January to February 1943. It was similar in design to the G-1 and was fitted with a pressurized cockpit. Like the G-1. it could be identified by the air scoop on the left side of the engine cowling above the supercharger air intake. Radio equipment consisted of a FuG 16Z in place of the earlier

6.4 km 5.7 km 58 5 m 740 m 770 m

branch installed a metal fairing between the fuselage and the drop tank. Flight tests conducted by Fritz Wendel with Bf 109 Werknummer  15939 revealed serious static instability about the vertical axis, both in high and low speed flight. A modified version of the fairing was supposed to be tested in an attempt to overcome this instability. Finally, after various experiments, a metal streamer was welded

Trials with Fixed Rudder Trim Tabs

Rudder ineffectiveness at small deflections had an unfavorable effect on firing passes and aiming corrections. This led in early June 1944 to the testing of so-called "bent rudder tabs." Werknummer  110039 served as a test-bed, and in several practice gunnery flights it proved the effectiveness of  the rudder labs. These tabs consisted of two 1-mm-thick Dural sheets of varying width and depth. The upper tab was bent to the right, the lower to the left. After several flights with labs of various depths it was discovered that effectiveness was fully sufficient at a depth of 30 mm. The distance between the tab and the trailing edge of the rudder was 10 mm. A BSK 16 gun camera was used to photograph the experiments. Elevator Vibration on the Wooden Tail of the Bf 109

On 10 July 1944 Regensburg Messerschmitt director Lindner reported to the handling characteristics project bureau that vibration was being encountered in aircraft with the wooden tail. Regensburg reported that since the prolonged rainy period at the beginning of July and the use of elevators with doubled fixed trim strip length (wooden elevators), a greater number of machines had been experiencing vibration in elevator control at speeds above 600 to 700 kph. The vibration appeared after several trouble-free flights. An immediate investi-

Nabern (WHN) with 1.5-mrn skinning between Ribs 2 and 6; and third, the wooden elevator built by the DEAG Firm of Butschowitz with 1-mm skinning between Ribs 4 and 6. plus wooden elevators by WHN of the same type as those made by DEAG. The control surfaces made by the WHN Firm were preserved according to Lackkette 33. while those by the DEAG Firm were preserved using the method of  the Warnecke and Böhm Firm. All of the control surfaces which had produced vibration and were removed in Regensburg were subsequently examined. There were 29 in total, all built by DEAG. All exhibited serious damage as a result of weather. In most cases glued joints had failed, especially on Rib 1 and along the rim strip. One of the elevators was sent to Oberammergau for an investigation of the preservation process. It was determined that painting had been carried out without the prescribed fabric covering, which was contrary to procedure. This system (Warbecke and Böhm) was always rejected by materials testing on account of the fact that it allowed through too much water. This was not the main reason for the vibration, however, rather it was the inadequate conservation protection of  the glue. Reference was made to earlier investigations in March 1943. At that time the wooden tails built by Fokker in Amsterdam also used a skinning of 1-mm between Ribs 4 to 6. The then confirmed speed of 750 kph produced none of the current complaints. Further investi-

However, Regensburg's original assumption that the cause of the vibration was the long fixed trim strip applied to these control surfaces was proved to be wrong by an experiment at Regensburg. Reducing the size of the trim strip and finally cutting it off completely failed to eliminate the vibration. As a result, it was determined that the cause of the vibration clearly lay in the elevator itself. The vibration only appeared in elevators with 1-mm plywood skinning between Ribs 4 to 6, but not in all such elevators. Ultimately, rudders were only permitted to be installed with 1.5-mm skinning between Ribs 2 to 6. The elevators by the DEAG Firm with 1-mm skinning and the unreliable Warnecke and Böhm preservation without fabric covering could no longer be used at all, on account of their permeability to water and the resulting effect on glued joints. All production was immediately switched to 1.5-mm skinning. In spite of all these measures there continued to be accidents involving wooden tail units, such as the one involving Bf 109 G-14 W.Nr. 460 628 at Stargard on 19 October 1944. The machine crashed from a height of 2 000 meters after

several parts of the aircraft broke away. The subsequent investigation revealed that the likely cause was the separation of the horizontal stabilizer from the tail section bearer. Other complaints were registered with the following: Bf 109 G-14 W.Nr. 464 396 (ERLA). Bf 109 G-14 W.Nr. 464 365 (ERLA), and Bf 109 G-6 W.Nr. 412 373. This was only the tip of the iceberg, however. A report to the E-Stelle Rechlin revealed that a total of 154 aircraft were examined by JG 27 and one Gruppe of JG 26 during the period from 8 to 13 December 1944. A significant number of problems with the wooden tails were found, and 36 machines could not be found airworthy. The probable cause was the inability of the wood to withstand the prevailing bad weather (dampness), and in particular bad or inadequate preservation. Among the most pressing demands to come from this was that ground crews be better trained in regard to the wooden components, and that a more expeditious way be found to transmit technical directives and announcements (in spite of the overall war situation!).

Date 29/7/44

Weather

Clear, hot

Machine Pilot Date Time of day

109 G-14 W.Nr. 165 706

109 G-14 W.Nr. 166 277

109 G-14 W.Nr. 165 721

109 G-14 W.Nr. 165 699

109 G-6 W.Nr. 166 249

18/7/44 morning

18/7/44 morning

18/7/44 afternoon

18/7/44 afternoon

18/7/44 afternoon

WH N formation of step on leading edge

WH N formation of step on leading edge

WH N formation of step on leading edge

WH N formation of step on leading edge

WH N formation of step on leading edge

WHN 1.5 mm betw. Ribs 2-6

WH N 1.5 mm betw. Ribs 2-6

WH N 1.5 mm betw. Ribs 2-6

Lackkette 33 satisfactory

Lackkette 33 satisfactory

Lackkette 33 satisfactory

DEAG 1.0 mm betw. Ribs 4-6 Warnecke & Böhm without fabric covering Rib 1 separated

0 mm

4 mm

4 mm

WHN 1.5 mm betw. Ribs 4-6 Warnecke & Böhm without fabric covering Rib 1 beginning to Separate 0 mm

(2) 0, (4)-2, (6)-1.5 -0.5 0 0 -1 -2 +0.5 -0.5 0 0

(2)-1 (4)-3.5 (6)-2 -0.5 +2 0 -0.5 -0.5 0 +0.5 0 0

(2}+ 1.5 (4) 0 (6) 0 -1.5 0 -1.5 0 -0.5 0 0 +0.5 0

(2) 0 (4) -6 (6) 0 +1 0 -1,5 0 +0.5

Bulges

right bottom 5 mm otherwise good

right bottom 4 mm otherwise good

deep impressions bottom

Trim strip

short

short

short

Result

satisfactory

satisfactory

satisfactory

Horiz. Stab. Manufacturer Complaint

Elevator Manufacturer Skinning Method of  Preservation Gluing Dihedral Loft Upper Lower Upper Lower

2     7  

Report No. 109 11 E 44

side side side side

left left right right

long

—

Page II

DEAG As well, on 18/7/44 ten machines were counted with WHN elevators and 1.5-mm skinning between Ribs 2-6 which were satisfactory.

-2 -0.5 -0.5 0

long

Test Reports

Messerschmitt AG Augsburg Test Report No. 109 18 E 43 Canopy Jettisoning 109 G Flight Test Dept. Date 2/11/43 Cause:

In spite of repeated improvements to the canopy jettisoning system of the 109 G, complaints were still being received that the canopy refused to jettison at all or did not do so without problems. Further jettison trials were subsequently carried out. the results of which appear below.

side at any lime after the jettison lever is pulled. In the first experiment the canopy lock  was activated at a speed of 350 kph and a yaw angle of 10 degrees. The canopy center section jammed. When the center section was knocked over the limiting wire snapped and the canopy struck the side of  the fuselage and then remained hanging. As a result of the impact the two pins on the right side of the canopy were so stressed and bent that releasing the jettison lock was no longer possible. Subsequently, a forced landing was made at Lechfeld with the canopy section hanging to the side. The jettison procedure

Test Reports

Messerschmitt AG Augsburg Test Report No. 109 18 E 43 Canopy Jettisoning 109 G Flight Test Dept. Date 2/11/43 Cause:

In spite of repeated improvements to the canopy jettisoning system of the 109 G, complaints were still being received that the canopy refused to jettison at all or did not do so without problems. Further jettison trials were subsequently carried out. the results of which appear below. Test Procedure:

A normal G canopy with the markings No. 109.135-135-002 and 109.117-003 was installed on the test-bed. In addition, the canopies were fitted with a relief spring with the marking No. A 17729 Z. Jettison trials were conducted with the above-named canopy. Result: The experiments were carried out as follows based on various theoretical considerations. First, the normal canopy lock was opened and then the jettison lever pulled. This sequence was chosen in spile of the

side at any lime after the jettison lever is pulled. In the first experiment the canopy lock  was activated at a speed of 350 kph and a yaw angle of 10 degrees. The canopy center section jammed. When the center section was knocked over the limiting wire snapped and the canopy struck the side of  the fuselage and then remained hanging. As a result of the impact the two pins on the right side of the canopy were so stressed and bent that releasing the jettison lock was no longer possible. Subsequently, a forced landing was made at Lechfeld with the canopy section hanging to the side. The jettison procedure may be seen on Page 4. After the normal jettison procedure failed to function smoothly, additional jettisoning assistance was installed based on a proposal from flight testing. As depicted in Illustrations 1 and 2, the upper end of the lever on the rear part of canopy 109.117003. which activates the locking bolts, was lengthened. A cable was attached to the lengthened lever and the rear wall of the canopy (Illustration 3). At a specified opening angle (after the limiting wire is broken) this pulls the locking pin. This ensures that the center section cannot swing out and bend the locking pins. At the same time, the cockpit

was uneventful. On the ground great force was required to pull the emergency jettison lever. 2nd Test (5/10/43) State of aircraft:

Additional cable on the canopy, which opens the lock after the limiting wire is broken. Otherwise as in 1. Result:

The canopy lock was released in straight and level flight at a speed of 350 kph. Afterwards, the folding canopy immediately opened to the right and the restraining wire immediately broke. As the canopy opened further, the additional cable released the locking bolts and the canopy with rear section was jettisoned smoothly. A detailed report on the experiment with photos of the  jettisoning is being issued by FAVA1. Augsburg, 7/10/43 FAFb/Wi/He.

Messerschmitt Flight Department Testing of Tail wheel Locking on tall tailwheel Me 109 - tailwheel Qualities Group Test Report No. 109 20 E 44 Date 8/11/44 Copy 12 Cause:

Frequent occurrence of swinging, especially on landing, during factory test flights with aircraft with the tall tailwheel, device No. 8-2926 G-5. There the cause was seen as imprecise installation of the tailwheel, while the FAM placed most of the blame on the uncommanded unlocking of the tailwheel, which could occur with minimal lateral forces on account of the rake of the locking bolt and its limited locking path. Procedure:

First tailwheel track deviations were measured using several Me 109s, and a test flight was conducted with the aircraft which produced the highest value. As the tailwheel delivered with W.Nr. 330 105 unlocked after a short time, leading to a strong swing, during the course of repeated modifications a version of the lock was developed, which so far has not led to further complaints. At the same time a tailwheel delivered by the Waiblingen Firm is under test on W.Nr. 167 227.

Results to Date: The greatest measured deviation of the neutral tailwheel position to the side was 1.2° to the left, furthermore, the tailwheel had sideways play of up to ±1.8°. Takeoffs and landings were possible without difficulty with a toe-in of 1.2°. Flight tests with eccentric locking bolts with up to 5° toe-in are now in process in order to more closely examine the effect of tailwheel track deviation on takeoff and landing behavior. The lock now installed in W.Nr. 330 105, with 5° angle of pressure on the locking bolts, external unlocking spring. lengthened tension spring in the pull cable plus lengthened cable length has so far not yielded any complaints in 20 flights. The new Elma tailwheel installed in Me 109 W.Nr. 163 227 with supplementary retraction spring on the connecting lever has not produced a complaint in 27 flights to date. The details of the modifications and dimensions of the new parts are contained in the following section.

Conveyor Line Production of the Bf 109 G Wing In the beginning the airframe sector of the German aviation industry was forced to build using the production line method because the numbers were initially lacking for conveyor line production. Wartime conditions resulted in a change in the fighter program which required consideration of mass production techniques. Although other aircraft were built in large numbers, it was generally acknowledged that conveyor lines could only be used for pure assembly work. The decision was made to also produce the 109 G wing on the conveyor line. The greatest difficulties arose from the fact that the Bf 109 was a type which had not been designed for conveyor line production. This means that the wing lacks the design breakdown, which is standard today. An attempt now had to be made to build the wing on the assembly line without design changes. In addition, use of the assembly line was of vital importance to increased production and had to begin by a certain deadline. Thus, no experiments were possible. Furthermore, because of the stage the program was at, it was necessary that numbers produced should increase continuously from the very first day. The conveyor line had to work from the very outset, and in particular produce interchangeable wings. Further difficulties were encountered in the spaces available, which were in no way suitable for conveyor line production. Available hall space was

As a further condition a significantly more precise component part production had to be achieved so that no fitting or ad justment work was necessary during assembly. More precise presswork tools were required, plus inspection gauges with which to check the ribs after manufacture. Since interchangeability was of particular importance, it was necessary to install the mounting points for fuselage, ailerons, landing flaps, slats, and wingtips in the structural framing. Furthermore, new uses had to be found for construction jigs rendered superfluous by the raw materials shortage. A work platform was attached to the construction framing so that the workers could move with it. Moving the construction frame back posed a particular problem, as there was very little room available and idling the production line had to be avoided if at all possible. The construction frame ran on a track  and was moved forward by means of a roller chain. Propulsion was by gear drive, whose revolutions could be adjusted by changing a set of gears. The resulting line speed was 4.1 to 24.5 cm per minute, which equaled to the output of 90 to 525 sets of  wings for a monthly operating time of 220 hours (status at the end of 1942). Altogether, three months after start-up of the line total time saved was 300 hours, which after the line got broken in was reduced a further 300 hours to 940 hours.

Reconnaissance Aircraft with Jumo 213 E In September 1944 a G-series Bf 109 was converted into a high-altitude reconnaissance aircraft. It was powered by a Jumo 213 E engine using E-4 fuel plus MW 50. The four-blade propeller, which had a diameter of 3.1 meters, was housed in a VS 19 hub. The greater engine output meant that the radiator had to be enlarged. A radiator with an area of 60 dm 2 was selected. which only increased the CWK value to 1.6 compared to the 1.45 of the smaller radiator (42 dm2). Theoretically, this should have resulted in a maximum airspeed loss of 10 kph. Expected maximum speed with climb/combat power and MW 50 was 780 kph at an altitude of 9 800 meters. Without power boosting maximum speed was 780 kph at 10 800 meters. These figures do not take into account the Mach effect! This would produce an approximate loss of  speed of 25 kph at an altitude of 10800 meters and 40 kph at 980 0 meters. The airframe was equipped with larger horizontal and vertical tail surfaces. The main undercarriage had no mainwheel fairings, however, the tailwheel was re tractable. No armament was planned, instead the aircraft was to carry a Type Rb 50/30 or Rb 75/30 camera. Takeoff weight was 3 700 kg. This machine. Werknummer 410 528, was tested at Berlin Staaken on 12 October 1944. Unfortunately, no further information is available.

The Bf 109 H High-Altitude Fighter

The RLM's demands for improved high-altitude performance were becoming ever more urgent, since the operating altitudes of enemy bomber and fighter formations and combat altitudes continued to increase. In the spring of 1942 Messerschmitt AG received a contract from the RLM to develop simultaneously with the "Special Carrier Single-Seater" a "Special High-Altitude Fighter." Since lack of production capacity made the prospects of initiating two special aircraft programs almost nil, especially if a rapid start-up of  carrier aircraft production was to be achieved, a version of the Bf 109 G with a lengthened wing and sturdier undercarriage was chosen. At the same time it was planned to bolster the aircraft's armament by installing two MG 151s in the wing roots. By exchanging the DB 605 for a DB 628 and adding extended wingtips, it was believed that a high-aititude fighter could be produced which met all of the current requirements (ceiling 14 km). Development of this type, which was designated the Me 155, proceeded very slowly in Paris. This was due in part to the recently

instructions of the RLM the Me 155 project was transferred to Blohm & Voss in Finkenwerder where it continued as the Bv 155.) On 23 April 1943 the proposal "Me 209 high-altitude fighter with DB 628" was submitted to the RLM. The performance figures for the project were almost the same as those of  the Me 155 high-altitude version. The RLM suggested to Messerschmitt verbally that it investigate ways to achieve even greater high-altitude performance, even if  it increased costs. The result was the Messerschmitt Projekt 1091 (extreme high-altitude fighter). Anticipated power plants were the DB 628 and the DB 603 with TKL 15 (exhaust-driven turbosupercharger 92279 by Hirth). In a report by Messerschmitt AG dated 26 July 1943 it was also proposed that a development series of high-altitude aircraft be produced in three stages. The first stage consisted merely of modifying a few components, especially the installation of a win center-section. Also given consideration was installing the DB 603 supercharger on the DB 605. In the second phase the wingspan was

and construction contract from the RLM for a "high-altitude fighter quick solution" based on the Bf 109 G. The intention was to increase the service ceiling of the Bf 109 with as little cost as possible. The main operational role of  this type was to be the interception of enemy high-altitude bombers and reconnaissance aircraft. A reduction in structural strength and a possible degradation of handling qualities in order to achieve improved high-altitude performance was accepted for both of these operational tasks. In order to save weight, the pilot's back armor was deleted and armament was limited to three weapons. Bf 109 G-3 W.Nr. 16281, which had been built at Regensburg in February 1943, was fitted with the DB 628 V8 and became prototype V 49. In trials the aircraft failed to achieve the predicted performance. On 22 December 1943 Heinrich Beauvais took the DB 628-powered V 54 (code DV + JB. Werknummer  15708) up on a flight which lasted from 14:42 to 15:00 hours. He assessed the flight, which took place at Augsburg, as follows: "The Messerschmitt AG company wanted an evaluation of yaw axis characteristics. The test was hampered by the loo small horizontal tail in conjunction with the lateral moment, which was known to be loo great. The vertical tail was insufficient for a production version! The lateral oscillations were uncomfortably high. Rudder effectiveness was poor, and, as mentioned, an enlargement of the entire vertical tail is necessary. In no case should the standard

In the attempt to achieve an optimum high-altitude fighter the idea of installing a Jumo 213 A in the 109 was also discussed. As at the department heads conference with Gen.Feldm. Milch on 29 October 1943, there was a lively debate concerning the expected performance and the considerable cost involved. But in the end no significant advantage could be seen for installing the Jumo 213 in the Me 109. At the beginning of 1944 several officials of the Messerschmitt AG proposed adopting the 109 H as a universal fighter. In a letter dated 2 February 1944 Project Director Hügelschäffer detailed the reasons against this idea. The performance of the Bf 109 H was compared to that of the Bf 109 K. The Bf 109 K was approximately 20 kph faster at ground level, furthermore, the K's speed advantage continued to rise to about 25 kph at maximum boost altitude. The Bf 109 H had in its favor a greater service ceiling and a somewhat better rate of  climb. The H's roll rate was significantly lower than that of the Bf 109 K. According to flight tests the Bf 109 H required 6 seconds to complete a roll, while the figure for the K was 4.5 seconds. Furthermore, the overall armament of the H was rated below that of the Bf 109 K. Finally, there was the reduced structural strength of n=4.5, which made it impossible for the Bf 109 H to exploit its lower wing loading. Further testing was overshadowed by a crash involving test pilot Fritz Wendel on 14 April 1944; Wendel escaped by parachute. Ludwig Bölkow hap-

These were used sporadically over England. An important point in the cancellation of Messerschmitt's high-altitude fighter was the advanced state of development of the Jumo 213-powered Fw 190 D-9 and the Ta 152. Furthermore, the situation in the air war suggested that operational altitudes were not about to increase as drastically as once expected.

P-51D Mustang. But this meant achieving an increase in speed over existing variants of 50 to 70 kph. This was the challenge facing project director Ludwig Bölkow. He was assigned the former design chief of the Bf 109. Richard Bauer, one of the "most gifted designers," as Bölkow said. As well, there came the series bureau of Messerschmitt Regensburg, plus ten experienced Bf 109 designers. His working staff consisted of a total of 140 men. As Bölkow himself said, for him this was the best apprenticeship with a big total responsibility. The tasks of the "Bf 109 develop-

Bf 109 K The Bf 109 G series was produced by several factories in a total of 16 variants with 82 different models. This led to increased difficulties in repairs and in the exchanging of parts (fit, accuracy of size). Far more than 1,000 changes had been introduced, and these were noted in modification directives. And so it was that Messerschmitt, at the urging of the RLM (fighter staff), initiated a special action.

ment bureau" still had to be laid down. The first planned point was the reworking of all series drawings for the Bf 109 G, incorporating the many modification directives. Also on the priority list was the elimination of the type's weak points, for example, the frequent undercarriage failures and its tendency to swing on takeoff and landing. Further changes were the installation of the DB 605 D or L engine, which offered better high-altitude performance, the previously mentioned speed increase, and the installation of an engine-mounted MK 108 cannon. All of these changes and improvements would not be allowed to delay or interrupt production. The first step was to relocate to Wiener Neustadt, which was still considered safe from Allied air attacks. The design bureau began its work in Wiener Neustadt at the beginning of 1943. For flight testing the various modifications, however, the team had to use what was available there. Lacking were a wind tunnel and various measuring devices. The aerodynamic reworking

The greater engine output meant that a larger oil cooler was also needed. Furthermore, as had been the case with the DB 605 AS engine, a larger supercharger air intake was necessary. Several improvements were also made in the area of the undercarriage, for example, the long tailwheel. As Dr. Ludwig Bölkow reported, all of this went back to a comparative measurement of the Fw 190. The latter had a taxiing angle which was 2° less than that of the Bf 109, 1° was subtracted, and the Bf 109 K was laid out based on the new angle, which led to a longer tailwheel. This was fully retractable and equipped with automatically-retracting wheel well doors. The bellcrank  for the rudder had to be modified to allow the longer tailwheel to retract. This bellcrank, which was mounted horizontally in the tail section bearer, was replaced by two individual levers mounted vertically in the end of the fuselage. As a result the two small bulges on either side of  the tail section bearer, features of the Gversion, disappeared. Recently it has been stated in various literature that the tailwheel doors could also be closed on the ground: the doors were controlled by the tailwheel, therefore they were open on the ground. Since the tailwheel retracted when the main undercarriage was raised and had no lock, leakage in the hydraulic system sometimes allowed the tailwheel to drop to some degree during flight. This led to considerable turbulence through the open wheel well and increased drag. Consequently, the doors were often forced closed

3. Furthermore, the access hatch on the left side of Fuselage Section 5 was relocated to Fuselage Section 4 because of the revised internal arrangement. The shape of the hatch followed that of the fuselage frame. As a result of relocating the compass system to a position further aft in the fuselage, the round access hatch on the left side of  the fuselage beneath the recessed foot step was deleted. Further design changes were carried out in the area of the cockpit, for example, the cockpit floorboards and most pilot seats were made of wood. The switch box with the automatic circuit breakers on the right cockpit wall was made larger and easier to scan. The operating controls for the radio and oxygen systems to the right of  the pilot's seat were mounted in a sort of  console. The standardized blind flying panel, which was also used in the Me 262, was formed as part of the instrument panel. As a result, a vertical speed indicator was now available. The four-lamp system for the undercarriage was replaced by three lamps or indicators. A mechanical indicator for the extended undercarriage, similar to that of  the Bf 109 F, was fitted. This indicator, which was visible from the cockpit, consisted of two metal rods; painted red, these projected from the upper surface of the wing when the undercarriage was extended. The door to the baggage compartment behind the pilot was enlarged and made more square. Two other important changes were a switch to thin steel sheet from aluminum for the leading edge slats and the use of wood in construction of  the tail section. The wooden tail gave im-

 from the Augsburg design bureau: but no examinations for stiffness were carried out. Fortunately the test pilot aborted his flight  and noted 'everything is too soft.' The design was changed within one night. Two days later the pilot flew again and then everything was in order." 

The changes compared to the Bf 109 G proved successful, and the specified speed and performance was achieved. Thus, the Bf 109 K was undoubtedly the most capable version of the Bf 109 and the most demanding to fly. At the same time it showed the limits of what could be achieved with piston-engined fighters.

Bf 109 K-4 The Bf 109 K was the only version of the K-series to be built in large numbers. By the end of 1944 a total of 856 K-4s left the Regensburg factory alone. Further confirmed numbers are not available. The aircraft never reached the units in these numbers, however, which was in part due to sabotage and the resulting accidents. For example, on 18 March 1945 the technical officer of JG 6 reported: Extract from the Chronicle of  Peter Schmoll, the Messerschmitt Factories in the Second World War

Newly-delivered aircraft are very prone to problems in the first 5 to 10 flying hours. It is almost always the same complaints, which are a burden to the unit technically and reduce its operational readiness. Complaints of the following nature appear almost regularly: elevator play in the mounting lever; loose spacers on the elevator control rods; too-long mounting bolts on the undercarriage suspension fittings; absence of slip markings on the mainwheels; leaky or plugged lines in the MW 50 system; shorts in the electrical system... loose and improperly fitted sparkplugs; loose mounting clamps on the hoses, etc. The following Rüstsätze (equipment sets) were planned for the K-4: Rüstsatz 1 consisted of gravity weapons (bombs), 1 x 500 kg, or 1 x 250 kg. These were mounted

20 cannon, one beneath each wing in gondola-shaped fairings. The weapons were fired using the B-1 button on the KG 13 A. The weapons were cocked automatically by switching on the safety switch on the SZKK (switch selector control box). Rüstsatz 6 was to be the installation of a BSK 16 ballistic gun camera in the left wing between nose ribs 3 and 4. Operation was automatic when the guns were fired. The following data are from a report by the GL/CE 2 (RLM) on 13 August 1944. Performance figures for the Bf 109 K-4/R2 reconnaissance aircraft were as follows: takeoff run was 380 m. Rate of climb at

ground level was 13.5 m/sec. Economical cruising speed was 645 kph at an altitude of  8.4 km. Range at that speed was 585 kilometers. Time to climb to 6 000 meters was 8 minutes. Maximum speed at emergency power was 580 kph at ground level and 710 kph at maximum boost altitude of 7 500 meters. Landing speed with a landing speed of 3 tons was 150 kph. The MW 50 system was also the subject of frequent discussion, for example, the question of dispensing with the overflow limiter in the MW 50 tank. On 26 June 1944 it was decided by C-E 2 III Bormann to proceed with the overflow limiter in the MW 50 tank in order to avoid further delays.

Me 109 L

The Me 109 L project was directly associated with the end of the Me 209 program. Following a conference of department heads at the office of the Technische Amt GL/C-E on 16 December 1943 the Oberammergau project office proposed the Me 109 L project. Wingspan was to be 13.3 m, which gave an aerodynamic area of 21.0 m2 with an aspect ratio of 1 : 8. The outer wings were to be taken from the Bf 109 H1 with reinforcements. The wing had to be modified forward of the spar in the undercarriage area in order to accept a longer, wide-track undercarriage. This wide-track  undercarriage was designed without camber and toe-in, and to accept either 700 x 175 or 740 x 210 wheels. The inner wing was to be built as a rectangular center section, with a continuous spar running at right angles to the fuselage axis, plus a tank  area of 170 liters between the main spar and the rear auxiliary spar. The fuselage was to be the same as that of the Bf 109 H-1 or Bf 109 K. Two modifications would have to be made, however. For one, the riveted wing bearer would have to be removed. In its place fittings were installed for the one-piece spar, which compared to the spar position of the Bf 109 G if it had

Me 109 L Weights

Armor

kg 1339 1879 104 93 105 87 14

Equipped weight

3 621

Airframe Engine Fixed equipment Other equipment Armament:

Pilot Fuel Oil Ammunition:

GM 1 + equipment

2 x MG 151 1 x MK 108

570 l x 0.79 MK 108 MG 151

106 455 50 38 100 160 4 530

The horizontal tail, which had a surface area of 2.8 m2, was to be taken from the Bf 109 H-1. The new vertical tail should have matched the current state of  flight testing. The anticipated engine was the Jumo 213 E standard power plant with annular radiator. This engine was to drive either a Junkers VS 9 four-blade wooden propeller with a diameter of 3.2 m or a three-blade Me P8 wooden propeller with a diameter of 3.4 m. Planned armament consisted of one engine-mounted MK 108 can-

Me 109 Z / Me 609

The idea of creating a single-seat destroyer or high-speed bomber from two single-seat fighters first appeared in a submission made on 9 December 1942. It was in keeping with a proposal to standardize aircraft to a few types. The first proposals for a fast aircraft from two single-seat fighters were based on the Bf 109 and Me 309. Such a combination had the advantage of taking less time to develop and put into production than a completely new aircraft for the same role. The cost for redesign and the designing of jigs and tools was only 30% of that of a new design. Another advantage of using an existing type was of course the accelerated testing, since prototypes could be produced quickly and, if necessary, in large numbers. Time wise, the so-called "double Bf 109." based on the Bf 109 G and its DB 605 engine, was the most effective solution. Another development possibility, albeit a more expensive one. was the use of  the Jumo 213 power plant. The following changes were seen as necessary for the double aircraft: the creation of a new wing

able. Modification of the main undercarriage made necessary the relocation of the undercarriage attachment points plus changes to the wheel wells in the wing. The higher all-up weight meant that larger wheels were required. Lengthening of the ailerons and slats was also necessary. It was anticipated that extra fuel tanks would be installed in the second fuselage in place of the pilot seat. A new. rectangular horizontal tail likewise had to be produced. The rest would be taken from existing production. Armament for the destroyer role was to be five MK 108 canon or four MK 108s and one MK 103. The bomber version would carry a reduced armament of two MK 108s but would have increased fuel tankage of 1140 liters. The planned bomb load was 2 x 1000 kg. Preliminary designs for a combination of two Me 309s powered by DB 603 G engines displayed similar possibilities to those of the Bf 109. Because of its more powerful engines, this version was expected to have a better performance. Structural layout was similar to that of  the Me 109 Z. The destroyer version was to

Double Bf 109 = Me 109 Z Provisional performance figures Purpose Power plant Engine data:

DB 605 B4 1,475 H.P. 1,310 H.P. 1,075 H.P. 1,230 H.P/7.1

Destroyer Jumo 213 B4 1,750 1,600 1,350 1,410/7.5

Equipped weight Crew Fuel Oil Ammunition Bombs Gross weight

4900 kg 100 82 5 90 340 (500) 6200 kg

5300 100 825 90 34 0 (500) 6600 kg

Max. Speeds at 0 m Takeoff power

580 kph

630

660

Climb and combat power

56 0

61 0

633

At opt. alt.

710 kph 69 0

74 0 72 0

>760 75 0

-17m/sec

-2 2

-2 6

at 0 m at opt. alt.

Fuel Takeoff power Climb and combat power Max. continuous power Climb and combat power

Takeoff power Climb and combat power

Rate of climb at 0 m, climb and combat power

Bomber DB 605

Jumo 213

C3 2,000 1,700 1,430 1,430/8.5

8300 kg

4700 100 1140 125 170 2000 8300 kg

5170 100 1140 125 170 2000

Loss of speed by 1 x 1000 kg bomb ca. 50 kph at 0 m,75 kph at opt. alt.

These performance figures were calculated in haste and must therefore be treated as approximate values. Mach numbers were not taken into consideration.

Double Me 309 = Me 609 Provisional performance figures Purpose Power plant Engine data:

Fuel Takeoff power Climb and combat power At 0 m Max. continuous power At opt. alt Climb and combat power Equipped weight Crew Fuel Oil Ammunition Bombs Takeoff weight Max. speeds

Destroyer DB 603 G B4 1,750 H.P. 1,575 H.P. 1,375 H.P. 1,480/7.1 6 380 kg 100 1 350 85 41 0 (500) 8325 kg

Bomber DB 603 G C3 1,740 1,550 1,350 1,450/8.5 6 100 100 1500 85 145 2000 10100 kg

Preliminary Experiments for the Me 209

Bf 109 F-1 Werknummer 5642, which had been built in November 1940, was converted to a wide-track undercarriage for preliminary experiments for the Me 209. The modified machine was coded SG + EK. The aircraft was powered by a DB 605 D engine cleared for 1450 H.P. for takeoff  and emergency power, furthermore, a retractable belly radiator was used. Total weight was 3100 kg. Testing began in February 1943 and encompassed takeoff characteristics, threepoint landings, night landings, dynamic longitudinal stability, and stalls. These revealed identical landing characteristics to those of the Bf 109 F or G. Furthermore, a stall in a turn with flaps retracted and engine at emergency power produced the same flow pattern as the Bf  109. Coming from outboard and inboard. the flow entered the area of the slats at an angle, leaving a relatively small triangular area behind the slats undisturbed. In this condition the aircraft wobbled strongly about the longitudinal axis, and these movements increased in intensity as wing loading rose. A full stall occurred only at large angles of attack. With the Me 209's high wing loading the effectiveness of the leading edge slats had to be improved. But since tests showed

(100 to 150 mm), poor stall behavior was accepted for the Me 209. Director of flight operations Baur carried out further trials with W.Nr. 5642; for example, night landing trials at Lechfeld at the end of March 1943 produced the following results: 1. The exhaust flames are a significant hindrance at night. 2. The bulb in the reflector sight (Revi) must be separately blacked out. since it is too bright even at the lowest setting. 3. UV instrument lighting is recommended, there is no illumination of the horizontal stabilizer pilch indicator. During the second night landing the torque link on the left undercarriage leg broke, whereupon the mainwheel turned sideways. Further trials were flown by Fritz Wendel in Werknummer 14003, VJ + WC. The machine had a takeoff weight of  3780 kg (!) and a landing weight of 3650 kg, According to a report dated 29 April 1943, stalling behavior deteriorated worse than expected. At the stall there was such a violent aileron movement that the pilot was unable to compensate even with both hands on the stick. At small angles of attack the aircraft rolled very quickly to more than 90 degrees. As well, no improvement could be expected by enlarging the slat openings.

Messerschmitt Regensburg Factory

Aircraft Production Bf 109 G

Assembly of Bf 109 G

Acceptance Flight Activity Dec. 1941 - Dec. 1942

Month

Year

Model

Werk-Nr.

November December January

1941 1941 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942 1942

G-1 G-1 G-1/R2 G-1 G-1 G-2 G-1 G-2 G-1 G-1 G-1 G-1/R1 G-1/R1 G-1/R1 G-2 G-2 G-2 G-2 G-4 G-4/trop G-4 G-4 G-4/trop

14001 14003 14010 14015 14022 14028 14029 14036 14037 14039 14064 14075 14092 14133 14151 14184 14231 14246 16001 16039 16093 16141 16183

February

March April May June July August September October November December

Werk.Nr.

to to to to to

14002 14009 14014 14021 14027

to

14035

to to to to to to to to to to to to to to to

14038 14063 14074 14091 14132 14150 14183 14230 14245 14268 16038 16092 16140 16182 16220

Quantity

Bf 109

G-1

2

2

G-1/R2

G-2

G-2/trop

0 9

1

23

1 2

2

28 1

40 33

18

10 1 27 68 52 50 50

2 3

48 27

20

3

3

converted to trop

48 8

46 54 48 80

1

48 8

67

1

80

98

23

Messerschmitt Werke Regensburg

AircraftProduction Bf109 G

Assembly Bf 109 G

Test Flight Activity Jan. 1943 - Dez.1943

Month

Year

Model

Werk - Nr.

Werk - Nr.

Stück

Januar

1943

G-4/trop

16221

bis

16250

30

1943

G-3

16251

bis

16269

19

1943

G-3

16270

bis.

16300

31

!943

G-4/trop

16301

bi s

16312

12

1943

G-6

16313

bis

16354

42

85

März

1943

G-6

16354

bis

16523

170

170

April

1943

G-6

16524

bis

16650

127

1943

G-6

18001

bis

18045

45

1943

G-6

18046

bis

18070

25

196

Mai

1943

G-6

18071

bis

18275

205

205

Juni

1943

G-6

18276

bis

18512

237

237

Juli

1943

G-6

18513

bis

18780

268

268

August

1943

G-6

18781

bis

18900

120

1943

G-6

160001

bis

160120

120

241

September

1943

G-6

160121

bis

160197

77

77

Oktober

1943

G-6

160196

bis

160363

168

166

November

1943

G-6

160364

bis

160565

202

202

Dezember

1943

G-6

160566

bis

160835

27 0

Bf 109 49

27 0

Total Total produced Jan. 1943 -Dez. 1943:

2168

Flight Activity

2166

38 54

4     3   

Februar

G-4/trop

2 7 5 7 6 1 7 1 2 25 11 17 4! 18 33 47 15 23 38 54 48 42 38

Total production from Nov. 1941 -Dec. 1942:

4    4   

G-4

48 42

38

128

92

4    4   

Messerschmitt Werke Regensburg

AircraftProduction Bf109 G

Assembly Bf 109 G

Test Flight Activity Jan. 1943 - Dez.1943

Month

Year

Model

Werk - Nr.

Werk - Nr.

Stück

Januar

1943

G-4/trop

16221

bis

16250

30

1943

G-3

16251

bis

16269

19

1943

G-3

16270

bis.

16300

31

!943

G-4/trop

16301

bi s

16312

12

1943

G-6

16313

bis

16354

42

85

März

1943

G-6

16354

bis

16523

170

170

April

1943

G-6

16524

bis

16650

127

1943

G-6

18001

bis

18045

45

1943

G-6

18046

bis

18070

25

196

Mai

1943

G-6

18071

bis

18275

205

205

Juni

1943

G-6

18276

bis

18512

237

237

Juli

1943

G-6

18513

bis

18780

268

268

August

1943

G-6

18781

bis

18900

120

1943

G-6

160001

bis

160120

120

241

September

1943

G-6

160121

bis

160197

77

77

Oktober

1943

G-6

160196

bis

160363

168

166

November

1943

G-6

160364

bis

160565

202

202

Dezember

1943

G-6

160566

bis

160835

27 0

Februar

Bf 109 49

27 0

Total Total produced Jan. 1943 -Dez. 1943:

2168

Flight Activity

2166

Messerschmitt Werke Regensburg

Aircraft Production Bf 109 G

Assembly Bf 109 G

Test Flight Activity Jan. 1944 - Dez.1944

Mont h

Year

Mod el

Werk - N r . W e r k - N r.

Quantity

Januar

1944

434

Februar

1944

305

März

1944

135

April

1944

343

Mai

1944

550

Juni

1944

659

Juli

1944

650

August

1944

704

September

1944

701

Oktober

1944

75 5

November

1944

54 3

Dezember

1944

537

Bf

109

G- 6

G-6/AS

G- 14

G-14/AS G-1 0

K- 4

Total Total produced Jan.1944 - Dez. 1944:

4     5   

6316

Flight Activity

6316

3165

325

479

1373

118

85 6

Messerschmitt Werke Regensburg

Aircraft Production Bf 109 G

Assembly Bf 109 G

Test Flight Activity Jan. 1944 - Dez.1944

Mont h

Year

Mod el

Werk - N r . W e r k - N r.

Quantity

Januar

1944

434

Februar

1944

305

März

1944

135

April

1944

343

Mai

1944

550

Juni

1944

659

Juli

1944

650

August

1944

704

September

1944

701

Oktober

1944

75 5

November

1944

54 3

Dezember

1944

537

Bf

109

G- 6

G-6/AS

G- 14

G-14/AS G-1 0

K- 4

Total Total produced Jan.1944 - Dez. 1944:

6316

Flight Activity

3165

6316

325

479

1373

118

85 6

4     5   

Messerschmitt AG

Type

License Production

Bf 109

Programm 223 , Anderungsstand B

1943

vom 15.8.1943 1944

Delivery plan

Nb 7b

To be delivered

Erla

4     6   

Total

delivered by bis 31.7.43 20

G-1 G-2 G-2 tp G-4 tp G- 5

20

K-1

930

G-6 tp

298

298

G- 6

1524

324

G-6/U2

500

K- 2

4810

160 384 266

9281

160 384 266 69

1521

Studie

G -1

20

20

v. 10.9.43

G- 2 G-2 tp G-4 tp

160 384

160 384 266

G- 5

391 930

K-1 G-6/U2 G- 6 K- 2

Ausgestellt am: Aussteller:

266

69

500 2X50

622

6530

-

12031

1521

21.9.43

8

9

10

11

12

1

2

35

40

45

50

50

50

50

165

170

195

60

50

60

190

140

160

160

40

1945 3

4

5

6

7

8

9

10

11

12

1

2

3

4

5

6

7

8

9

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

30

250

60

210

290

310

330

350

370

390

400

400

380

350

300

250

200

150

100

30

320 3851

340 4191

360 4551

380 4931

400 420 5331 5751

440

450 6641

450 709!

430 7521

400 7921

350

6191

8271

300 8571

250 882!

200 9021

150 9171

80 9251

9281

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

30

450

290 210

500

500

500

500

500

500

500

500

500

450

450

350

250

150

100

50

20

500

550

550

550

550

550

550

550

550

500

4881

5431

5981

6531

7081

7631

8181

8731

550 9281

550

4331

200

210

1931 2171

250 2421

260

1721

2681

270 295!

280 300 3231 3531

31

46

50

50

50

50

300

200

30

170

169

194

240

45

235

200

240

1721

1961 2241

280

geändert am:

280

330 2571

380 2951

420 3371

410

460 3831

Geheim! 1. Dies ist ein Staatsgeheimnis im Sinne des §88 RSTGB 2. Weitergabe nur verschlossen

+

9831

30

500 400 300 2(X) 150 UK) 50 10331 10831 11231 11531 11731 11881 11981 12031

Umschaltung auf Höhenjäger vorgesehen z.Zt. in Bearbeitung

Messerschmitt AG

Type

License Production

Bf 109

Programm 223 , Anderungsstand B

1943

vom 15.8.1943 1944

Delivery plan

Nb 7b

To be delivered

Erla

4     6   

Total

delivered by bis 31.7.43 20 160 384

G-1 G-2 G-2 tp G-4 tp G- 5

20 160

K-1

930

G-6 tp

298

298

G- 6

1524

324

G-6/U2

500

K- 2

4810

384 266

9281

266 69

1521

Studie

G -1

20

20

v. 10.9.43

G- 2 G-2 tp G-4 tp

160 384

160 384 266

G- 5

391 930

K-1 G-6/U2 G- 6 K- 2

Ausgestellt am:

266

69

500 2X50

622

6530

-

12031

1521

8

9

10

11

12

1

2

35

40

45

50

50

50

50

165

170

195

60

50

60

190

140

160

160

40

5

6

7

8

9

10

11

12

1

2

3

4

5

6

7

8

9

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

30

250

60

210

290

310

330

350

370

390

400

400

380

350

300

250

200

150

100

30

320 3851

340 4191

360 4551

380 4931

400 420 5331 5751

440

450 6641

450 709!

430 7521

400 7921

350

6191

8271

300 8571

250 882!

200 9021

150 9171

80 9251

9281

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

30

450

290 210

500

500

500

500

500

500

500

500

500

450

450

350

250

150

100

50

20

500

550

550

550

550

550

550

550

550

500

4881

5431

5981

6531

7081

7631

8181

8731

550 9281

550

4331

210

250 2421

260

1931 2171

2681

270 295!

280 300 3231 3531

31

46

50

50

50

50

300

200

30

170

169

194

240

45

235

200

240

1721

1961 2241

280

280

330 2571

380 2951

420 3371

410

460 3831

Type

Bf 1099

Delivery plan NB 7b

Total

1943 9 Delivered by 8

C- 2 G-2/R1

914 10

bis 31.7.43 914 10

G- 4

636

G-4/R3 G- 6

HO 1420

G-6/U4

1445

648 46

K- 2

10340

-

G-6/R3

4(1

22

G-6/R2

250

-

G- 8

2100

-

15

17235

2355

280 300 2635 2935

635 80

130

110

80

100

150

190

250

250

10

Ausgestellt am:

2355

21.9.43

11

12

1945 1

2

3

4

5

6

7

8

9

330

485

560

650

720

790

790

790

790

790

790

790

690

540

390

240

90

20

5

300

95

80

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

20

40

50

60

70

80

90

90

90

90

100

100

100

100

100

100

100

100

100

100

100

100

100

70

35

330 3265

370 400 430 3635 4035 4465

470 525 4935 5460

585 6045

660 6705

750 830 7455 8285

900 9185

900 900 900 900 900 900 800 650 500 350 200 100 50 10085 10985 11885 12785 13685 14585 15385 16035 16535 16885 17085 17185 17235

190 150

220 200

580

555 100

530

300

200

500

890

990

1090

1190

1290

1390

1490

1290

1090

890

690

490

290

90

20

5

210 250

510

10

22792

10

10

65

-

9

10

220

2040

8

10

13

-

7

10

150

240

6

10

648 46 22

5

3

10

1

13995 40

4

2

18

924

G- 8

1944 1

100

635 80

G-6/R3 G-6/R2

12

170

G- 4 G-4/R3

K- 2

11

182

G-2/G-2/RI 924

G- 6 G-6/U4

10

64

v. 10.9.43

80 1638 3199

Programm 223 , Anderungsstand B vom 15.8.1943

1

Studie

636

500 400 300 2(X) 150 UK) 50 10331 10831 11231 11531 11731 11881 11981 12031

Umschaltung auf Höhenjäger vorgesehen z.Zt. in Bearbeitung

1. Dies ist ein Staatsgeheimnis im Sinne des §88 RSTGB 2. Weitergabe nur verschlossen

To be delivered

9831

30

+

Geheim!

geändert am:

Messerschmitt AG

Aussteller:

4

1721

21.9.43

License production

4     7  

3

200

Aussteller:

WNF

1945

13

5 10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

40

50

60

70

80

90

100

100

100

KM)

100

100

100

100

100

100

100

100

100

100

100

70

35

520

580

910

1000

1100 1200

4797

660 745 6202 5457 __ _

830

4217

7032

7942

8942

5

20

20

182

310

2537

2847

370 480 3217 3697

geändert am:

600 400 200 100 50 1300 1400 1500 1600 1400 1200 1000 800 10042 11242 12542 13942 15442 17042 18442 19642 20642 21442 22042 22442 22642 22742 22792

Geheim! 1. Dies ist ein Staatsgeheimnis im Sinne des §88 RSTGB 2. Weitergabe nur verschlossen

Messerschmitt AG License production

Bf 1099

Total

1943 9 Delivered by 8

C- 2 G-2/R1

914 10

bis 31.7.43 914 10

G- 4

636

G-4/R3 G- 6

HO 1420

G-6/U4

1445

648 46

K- 2

10340

-

G-6/R3

4(1

22

G-6/R2

250

-

G- 8

2100

-

15

17235

2355

280 300 2635 2935

To be delivered

WNF

Type

Delivery plan NB 7b

635 80

130

110

80

100

100

150

190

250

250

10

Ausgestellt am:

22792

2355

21.9.43

Aussteller:

Beginning with the G-5 series, the Bf 109's firepower was increased through the replacement of the two 7.9-mm MG 17 machine-guns with two 13-mm MG 131s. This resulted in the characteri-

12

1945 1

2

3

4

5

6

7

8

9

330

485

560

650

720

790

790

790

790

790

790

790

690

540

390

240

90

20

5

300

95

80

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

20

40

50

60

70

80

90

90

90

90

100

100

100

100

100

100

100

100

100

100

100

100

100

70

35

330 3265

370 400 430 3635 4035 4465

470 525 4935 5460

585 6045

660 6705

750 830 7455 8285

900 9185

900 900 900 900 900 900 800 650 500 350 200 100 50 10085 10985 11885 12785 13685 14585 15385 16035 16535 16885 17085 17185 17235

190 150

220 200

580

555 100

530

300

200

500

890

990

1090

1190

1290

1390

1490

1290

1090

890

690

490

290

90

20

5

210 250

510

10

-

11

10

65

2040

10

10

220

G- 8

9

10

13

-

8

10

150

240

7

10

648 46

4     7  

6

10

1

22

5

3

10

924

13995 40

4

2

18

635 80

G-6/R3 G-6/R2

1944 1

170

G- 4 G-4/R3

K- 2

12

182

G-2/G-2/RI 924

G- 6 G-6/U4

11

64

v. 10.9.43

80 1638 3199

10

1

Studie

636

Programm 223 , Anderungsstand B vom 15.8.1943

13

5 10

10

10

10

10

10

10

10

10

10

10

10

10

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Geheim! 1. Dies ist ein Staatsgeheimnis im Sinne des §88 RSTGB 2. Weitergabe nur verschlossen

Beginning with the G-5 series, the Bf 109's firepower was increased through the replacement of the two 7.9-mm MG 17 machine-guns with two 13-mm MG 131s. This resulted in the characteristic bulges on both sides of the engine cowling. The aircraft's basic armament consisted of two MG 131s and an enginemounted MG 151/20. Front view of the Bf 109 G-5. In spite of the two bulges, early examples of  this variant were characterized by a good aerodynamic shape.

Bt 109 G-6/R6 parked at the edge of a forest for concealment. This photo provides an excellent view of  the MG 151/20 cannon be-

neath the wings and the two large circular bulges over the MG 131s. Note the lovely spiral on the large propeller spinner.

Beginning in May 1943 some Bf 109 G-6s had the Morane antenna mast for the FuG 16ZY radio system fitted beneath the left wing. This radio was used in conjunction with the Y-method of fighter control. Arming the MG 151/20 wing cannon of a Bf 109 G-6 of JG 27 in North Africa.

The instrument panel of  a Bf 109 G. SZKK 3 switch-counting and control box, Revi C 12/g gunsight, cluck, magneto selector switch, repeater compass, turn-and-bank  indicator, propeller pitch indicator, undercarriage position indicator, finecoarse altimeter, airspeed indicator, boost pressure gauge. RPM indicator, coolant and oil temperature gauge, fuel and oil pressure gauge, altimeter, and fuel gauge.

Bf 109 G-6. On the far left next to the gunsight is the repeater compass, beside it the turn-and- bank indicator, beneath it the airspeed indicator and beside it the fine-coarse altimeter. Clearly visible beneath the instrument panel is the mount for the engine-mounted cannon, which has been removed. Some late variants of the Bf 109 G had their arm ament bolstered through the installation of  Rüstsatz 5, which consisted of two MK 108 cannon in the underwing gondolas.

Three-view drawing of  the Bf 109 K-4 taken from an aircraft type sheet. This American proudly poses for a souvenir photo in front of a Bf 109 G10 on a south-German air base after the end of  the war.

General Arrangement Drawing Bf 109 K-4 (Günter Sengfelder)

Bf 109 K-6: General arrangement and control surface deflections.

Trials with 660 x 150 Wheels

For the purpose of undercarriage leg trials Bf 109 G W.Nr. 14003 was brought to a takeoff weight of 3.8 tons. This resulted in increased numbers of tire failures and led to extended trials with the 660 x 150 wheel with tire and inner tube. As well, there were growing complaints from the front-line units. During the period from July to August 1943 far in excess of 100 takeoffs and landings were made by the test-beds W.Nr. 14003 and W.Nr. 160031 in an effort to determine the cause of the failures. At the same time, comparative trials were conducted with 650 x 150 and 660 x 160 wheels with free-lying steel brake drums. In some cases the normal tires had a very short life, some only 2 to 4 circuits, and such was the problem that an immediate solution had to be found in conjunction with the Continental Company. Trials were carried out at Lechfeld airfield near Augsburg. The poorest areas of this landing field were comparable to conditions at forward airfields. Two new wheels with new tires and inner tubes were installed on the Bf  109 G-1 test-bed. Werknunmer  14003. The wheel loading at rest was divided as follows: 1.6 tons per mainwheel and 0.6 tons on the tailwheel. The brakes were used harshly on all landings, and once on the

(braking) the tire failures reappeared. The subsequent use of reinforcing bands increased the life of the same tire to an average of 15 to 20 circuits. This was such an improvement that a message was immediately sent to the units. This was no ideal solution, however, and therefore the trials went on. Redesigned Elektron die cast wheels with free-lying steel brake drums by EC4 (drawing no. 8-2089 B-2) were now put into use. A total of 120 circuits were flown with these wheels under identical test conditions. Heavy braking was used to simulate the thermal loads and high external temperatures to be expected in frontline use. The average daytime temperature during these experiments was 32° C. The stress through brake heat was increased further by Hying circuits in quick succession, in some cases 25 circuits in the space of one hour. In spite of these stresses the tires withstood 120 circuits and even after examination by the EC Company were in such condition that they were approved for further use. The tires were changed only once per wheel. The reason for this can only be suspected to be pushing the testbed too hard. These new engine cowling wheels with free-lying brake drums represented such an improvement that it seemed

The Bf 109 undercarriage. Here details of the undercarriage leg with main wheel, f airing, brake line, stub axle, and shock strut head.

Front and rear views of  the Bf 109 K mainwheel (660 x 190).

Bf 109 K Series Deliveries of the K-Series, which was to be the final major production variant va riant of the Bf 109, began in midm idOctober 1944. The previously-mentioned RLM transcript from August 9,1943 9,194 3 reveals that the manufacture of 10 pre-production pre-production aircraft aircraft by WNF was planned for September 1943. Series production of the Bf 109 K-2 was subsequently to begin at Erla, WNF and Messerschmitt Regensburg in February 1944. Further, the Bf 109 K-1 K-1 was supposed to replace the G5 in production at Erla from July 1944 and it was specified that, like the G-5, the K-1 was to be

equipped with a pressurized cockpit. Quantity production was also planned of a K-3 series which was to be built as a fighter and, in its K-3/R2 form, as a reconnaissance aircraft with a pressurized cockpit. In March 1944, however, it was decided that in the interests of of a standardization of Bf 109 production produ ction all other K-Ser K-Series ies would be cancelled pending the introduction to production production of the K-4 series. Therefore the only variant of the K-Series to reach quantity producp roduction was the Bf 109 K-4.

This Bf 109 109 K-4 K-4 with wit h the Werknummer Werknummer 330 330 130 130 was flown by the Messerschmitt factories in various variou s trials tri als in the autumn of 1944. The identifying features of the K-Series are clearly evident: the revised, forward location of the fuel tank filler point and the octane triangle beneath it, the DF loop which was displaced further back along the fuselage spine, the revised equipment hatch door, the tall tailwheel and the tall fin and rudder with two fixed trim tabs. (Radinger)

Bf 109 K-4

167 

Bf 109 K-4

Bf 109 K-4 While the K-1 to K-3 Series, which got no further than the project level, were to retain the DB 605 A power plant, the K-4 was conceived around the DB 605 D and accordingly differed little from the G-10. In contrast to the G-10, K-Series aircraft were not conversions of older machines, and unlike the G-10 the vast majority of the aircraft delivered were equipped with the DB 605 D engine, although a few exceptions are known among early series aircraft which retained the DB 605 AS engine. According to the existing production programs, which were also continually revised regarding K-4 production, at one time the construction of over 12,700 K-4s was planned, with production stretching from July 1944 until March 1946. In fact only a fraction of these projected numbers were built and delivered. The actual number of K-4s built is unknown; a total of 534 had been delivered by November 30, 1944, and it may be assumed that at least another 1,200 machines had been built by the time the war ended. The known K-4 Werknummer blocks are: 330000-331000 331300-331500 332000-333000 333800 - 334000 334000 - 334300 335000 - 335300 570000-571000

Mtt Reg. Mtt Reg. Mtt Reg. Mtt Reg. Mtt Reg. Mtt Reg.

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The vast majority of K-4s were built by Messerschmitt, and the company's planned production figure, according to the production program as it stood on November 30,1944, was 3,598 aircraft, all of which were to be delivered by July 1945. In addition, Erla was to build 2,895 of the K-4/R6 version in the period January-April 1945. Production did in fact begin there, probably in early 1945, but it is not known how many aircraft were built and delivered before Leipzig was occupied by American forces on April 19, 1945. The only known example of an Erla-built K-4/R6 is Werknummer 570362, which was accepted by BAL on February 16,1945. Furthermore, WNF was supposed to construct another 2,820 K-4/R6s from May 1945 to March 1946, while KÖB was to construct 1,000 K-4s in the period March-June 1945 and a further 2,700 of the K-4/R6 version by March 1946. It is not known if production of these planned series began and if so what Werknummer blocks they were assigned. The K-4 began reaching active units assigned to the Reich Defense in mid-October 1944 and those in the East somewhat later. Thus deliveries of the K-4 obviously began some time before those of the G10, The first known loss of a K-4 occurred on October 19, 1944, when Werknummer 330305 crashed while being flown by Uffz. Pospiech of 3./FIÜG 1 (S). The same day the Sonderkommando OKL lost a K-4 with the Werknummer  330319. The aircraft's pilot, Ofw. Galli, was apparently injured in the incident. By the end of the war the K-4 had been delivered to the following units:

Erla

Messerschmitt Bf 109 K-4

168 

Messerschmitt Bf 109 F, G, & K Series • An Illustrated Study

The following photographs were taken in November at Neuruppin, where III./JG 77 was resting and refitting and reequipping with the K-4. Here Hptm. Menzel is seen preparing for a practice sortie in "White 1," a K-4 of 9. Staffel with the Werknummer 330 204. This aircraft was lost on January 1, 1945, while taking part in Operation "Bodenplatte," when Lt. Abendroth was shot down by flak in the Rosendaal area and subsequently taken prisoner. (Buck)

"White 2," another K-4 of 9./JG 77 at Neuruppin in November 1944. (Buck)

A ground collision involving two K-4s of 9./JG 77. Sitting in "White 8," which is just visible beneath "White 3," was Uffz. Schulz. Luckily Schulz escaped serious injury and was able to climb out of his wrecked machine. (Buck)

Bf 109 K-4

III./JG 1, II./JG 2, III./JG 3, I., III./JG 4, II./JG 11, III./JG 26, II., III., IV./JG 27, III./JG 51, II., III./JG 52, II., III./JG 53, I., II., III./JG 77, I./NJG 11, II./KG(J) 6 and I. and II./KG(J) 27. Most of these Gruppen were only partially equipped with the K-4 and continued to fly numerous G-14s and G-10s as well. Only III./JG 3, III./JG 26, III./JG 53 and III./JG 77 were equipped, at least for a time, solely with the K-4. Externally, the K-4 differed little from some G-10s. The engine installation of both versions was identical. The K-4 also had the new, wide-bladed VDM 912159 propeller and the deeper F0 987 oil cooler, as well the two side fairings to accommodate the larger crankcase of the DB 605 D. Like the G-10, MW-50

169

power boost was standard equipment on the K-4, and as a result the complete engine designation was DB 605 DM. In addition the K-4 was built with radiator cutoff valves like those which had been retrofitted to limited numbers of F-Series aircraft in 1941. The cockpit area, too, was virtually unchanged from that of the G-10. The K-4 exhibited the various known styles of the so-called "agglomerations", the riveted-on fairings behind the bulged engine cowling. The K-4 received the Erla-Haube as standard equipment and the antenna mast was often dispensed with; in this case the aerial was attached to the fuselage spine in the usual manner. Because of the high attrition in antenna masts and safety springs resulting from the Erla-Haube being opened too far,

Four K-4s of 3./JG 77 at Neuruppin airfield on a dreary, foggy November day. All wear the Geschwader emblem of JG 77 on the engine cowling. (Buck)

Two shots of "White 17," a K-4 of 9./JG 77 with the Werknummer 330 230. On January 1,1945, Uffz. Munninger of 10./  JG 77 was shot down and killed by anti-aircraft fire near Tilburg while flying this aircraft. Behind the fusela

170

Messerschmitt Bf 109 F, G, & K Series • An Illustrated Study

Aircraft of 11./JG 77. In the center is "Yellow 8," a K-4 with the Werknummer 330 176. This aircraft was lost as the result of a mid-air collision near Neuruppin on November 27,1944, its pilot, Lt. Zieher, losing his life. (Böttner)

a technical directive was issued in November 1944 in front of the rear insulator, sloped forward 74 cm to (TAGL II Bf 109 A2 Nr. 3, 427/44) which contained the fuselage spine. detailed instructions to the front-line maintenance The filler point for the main fuel tank was moved shops for the replacement of the antenna mast and, forward to a location between Frames 2 and 3-as if required, conversion of the antenna installation to always on the left side of the fuselage. Conversely the current production standard. In the modification the DF loop was moved aft and installed between process the aerial was simply hooked into a hole in Frames 3 and 4. The round sheet-metal plate over the fuselage spine, led through the DF loop and the footrest behind the wing root was deleted on the attached to the fin with a metal lashing. The fixed K-4. The radio equipment access hatch was also antenna, with an overall length of 3.5 meters, con- moved forward and was located between Frames 4 sisted of impregnated hemp rope (85 cm), an eye, and 5 in a somewhat higher position than before. flexible wire (40 cm), the actual antenna between the The hatch is often depicted with a sloped upper insulators (167 cm), flexible wire (41 cm) and the edge, but this was in fact horizontal, while the bottom safety spring, which was hooked onto the fin. The edge sloped slightly to the front. fuselage antenna lead-in, which was attached 51 cm The enlarged tail unit was a standard fit on the K-

Uffz. Fröhlich of 11./JG 77 in front of a K-4 of 10./JG 77 with the code "Red 2," photographed at the end of December 1944 at Düsseldorf-Ratingen. It is obvious that

K-4s of 11./JG 3 parked and meagerly brish-camouflaged at Pasewalk airfield in February 1945. (Kallerhoff)

Bf 109 K-4

Hptm. Strasen, who took over III./JG 4 just before the end of the war, by the tail of his K-4, which wears the black/  white/black fuselage band of JG 4. Visible on the fuselage band is the vertical Gruppe bar, which on aircraft of the Gruppenstab of Ill./JG 4 was red. (Strasen)

Above: Lt. Landt, Staffelführer of 11./JG 53, in the cockpit of his aircraft "Yellow 1" at Kirrlach, February 22,1945. This K-4 may be the same machine - W.Nr. 332 660 - in which Lt. Landt collided with a Mustang during a dogfight near Bretten a day later. Landt was injured in the incident and was forced to bail out of his damaged aircraft. (Landt) Right: "Yellow 1" again. The black fuselage band worn by aircraft of JG 53 is clearly visible behind the Balkenkreuz. (Landt)

171

4, and in most cases the aircraft's rudder featured the Flettner tab as well as the two fixed tabs; however, there were rare examples which did not receive the fixed tabs. In general all K-4s were supposed to receive the long tailwheel, which was intended to be retractable. The tailwheel size was 350 x 135. A few K-4s were nevertheless fitted with the short tailwheel of the G-6. Those aircraft with the long, retractable tailwheel were fitted with two clamshell doors to cover the tailwheel recess. The wing of the K-4 had the large, rectangular fairings for the 660 x 190 mainwheels, and externally was almost indistinguishable from that of the G-10 series. There were several differences, however. The ailerons of the K-4 were fitted with small inset adjustable trim tabs. It was also planned to introduce

172

Messerschmitt Bf 109 F, G, & K Series • An Illustrated Study

Lt. Potreck, a pilot in the Stab of III./JG 53, seated in his brush-camouflaged K-4 during preparations for a sortie in March 1945. (Landt)

"Yellow 15," a K-4 with the Werknummer 332 956, belonged to 11./JG 53 at Kirrlach in March 1945. On the left is Ofw. Polak and on the right Ofw. Scheer. Note the last four digits of the Werknummer on the aft fuselage. (Scheer)

Two pilots of 11./JG 3 - Gefr. Zitzmann and Uffz. Lehnen - in front of "Yellow 2," a K-4 with the Werknummer 332 506. This aircraft was lost in combat with Yak-9s near Stettin, when Uffz. Günter was shot down and killed. (Suhr)

Uffz. Suhr by the tail of his K-4, on whose rudder the Werknummer 334 210 may be seen. This aircraft has the short tailwheel, but it appears that the tailwheel recess doors for the long tailwheel are nevertheless present. (Suhr)

Bf 109 K-4

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Three shots of "Yellow 8," a K-4 of 11./JG 3 at Pasewalk in March 1945. The pilots of 11./JG 3 in front of "Yellow 8." Standing, from the left, Uffz. Zimmermann, Uffz. Massing, Gefr. Zitzmann, Lt. Walter, Uffz. Deskau and Uffz. Suhr; sitting, FhjFw. Gogler, a Luftwaffe Female Auxiliary and Uffz. Lehnen. Note the antenna wire which runs through the DF loop and is attached to the fuselage spine. (Suhr)

Above: The open, uncamouflaged placement of the K-4s of 11./JG 3 is noteworthy, because by this time the Russian Air Force was in almost complete command of the skies over eastern Germany. In the foreground the personnel of 11./JG 3 once again; from left Uffz. Massing, Lt. Walter, FhjFw. Gogler, Gefr. Zimmermann and an unidentified pilot. (Suhr) Left: This aircraft was flown by Lt. Walter, later transferred to IV./JG 3 and here seen in front of his aircraft.

174

Messerschmitt Bf 109 F, G, & K Series • An Illustrated Study

Fw. Strebel of 11./JG 3 in front of his aircraft "Yellow 4," presumably again the K-4 with the Werknummer 334 210. Note the end of the antenna wire behind the fuel tank filler inlet, the octane triangle with the c3 marking and the name "Ingeborg" beneath the cockpit. (Suhr)

the small mainwheel well doors similar to those which had been planned for the earlier Bf 109 G. These well doors were often removed by the frontline units. Installation of the antenna mast for the FuG 16zy below the left wing was standard. One change not externally visible was the relocation of the oxygen bottles from the rear fuselage to the right wing. Armament of the K-4 consisted of an enginemounted MK 108 cannon, which by now was installed on the production line, as well as two MG 131 machine-guns above the engine. There were aircraft, however, which were delivered with an MG 151/20 engine-mounted cannon. Radio equipment was similar to that of the G-10, with the FuG 16ZY and 25a as well as the Peilrufanlagfe direction finding (DF) equipment. A series of Rüstsätze was planned for the K-4, of which only R3, the standard range-increasing modification with 300-liter auxiliary fuel tank, saw largescale use. R1 was the planned installation of an ETC 500 IXb rack for one 250 kg or 500 kg bomb, R4 two underwing, gondola-mounted 20-mm cannon and R6 the installation of a BSK 16 gun camera in the left wing. Like the G14 and G-10 before it, a bad-weather version of the K-4 was to be built, designated K-4/  R6. It has not been confirmed that this version was in fact built in large numbers. And finally there was a reconnaissance version, the K-4/R2, which could be equipped with an Rb 50/30 or Rb 75/30 camera as well as an FuG 16 ZS in place of the FuG 16 ZY. There is likewise no proof that the K-4/R2 was actually built.

Bf 109 K-4

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Different styles of attaching the antenna wire to the vertical stabilizer. The tailwheel doors are illustrated in the open and closed positions.

Lt. Landt of 11./JG 53 taxis out for takeoff in "Yellow 14," a K-4, in early 1945. Note the small wheel well doors beneath the wings, while the undercarriage leg fairings are absent (Landt)

176 

Messerschmitt Bf 109 F, G, & K Series • An Illustrated Study

Wrecked German aircraft at Kaufbeuren airfield in the summer of 1945. On the right is "Chevron 1," a K-4 of the Gruppenstab of Ill./JG 53 which Lt. Bernhard had been forced to belly-land at the airfield on April 19, 1945. Note the broad, black fuselage band with the Gruppe bar behind it, as was usual on aircraft of Ill./JG 53 in February 1945. (Chapman)

The adjutant's aircraft of Ill./JG 27, a K-4 with the Werknummer 330 255, as found at Wunstorf air base by advancing Allied troops in April 1945. All the characteristic features of the K-4 are clearly visible - the equipment bay door which

Bf 109 K-4

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The remains of "White 16," a K-4 of 9./JG 53, as it looked on a forward airfield in southern Germany after the end of the war. Note the broad fuselage band with the Gruppe bar behind it. Clearly visible are the large mainwheels and broad propeller blades. (Petrick)

Bf 109 K-6 The K-6 series was to enter production alongside the K-4 in January 1945. The production of 3,570 machines was planned, 2,070 by Erla and 1,500 by WNF. According to a report by the main department of the OKL (Hauptausschusses) on October 31, 1944, it was planned produce the K-4 and K-6 in a ratio of 2:1. In any case it is not known if the K-6 actually entered production and there is still no known Werknummer block for the K-6 series. It is known, however, that at least one K-6 was being tested at Rechlin as early as autumn 1944. The K-6 was to be largely similar to the K-4; the only difference was to be the installation of two MK 108 in the wings, which is why the K-6 was designated a "heavy fighter." On the other hand the projected Bf 109 K-10 and K-12 variants progressed no further than the project stage.

"Black 2," another K-4, originally belonged to 14./JG 53. In June 1947 it still lay in a forest at the former forward airfield at Reichenbach. Note the wavy line, used as a Gruppe symbol by IV./JG 53, on the black fuselage band. (Willbold)