! e e r a r a h w S -
Simplified Aircraft Design Spreadsheet f Version 1.0
Better to save this spreadsheet as a renamed copy before changing it for your
LEGAL NOTICE !
g n Stall speed i g d Takeoff air density n a i o W L Wing CLmax power loading
Copyright C 2003 by Daniel P. Raymer. All Rights Reserved. Se
Inputs (kts) (slugs/ft^3) (lb/hp)
Calculated Values 8 St Stall speed (ft/sec) 0 Dynamic pressure (psf) 1 Wing loading (W/S) (psf) 0.14
If sizing to a range requirement, ignore this input for now but enter it later when Wo is calculated and engine is selected
n w o n e k n - i o g n W e Engine Power Number of Engines
(hp -each)
Swet/Sref s i Cfe e n Aspect ratio (A) i g (slugs/ft^3) n Cruise air density e ( Cruise velocity (kts) t n e ) m d e e r t i (lb/hour u c e q l Engine SFC /bhp) e r e s Prop Efficiency (cruise) e t g e y Range (nmi) n t a r o a n o t (%) g Fuel allowance n i Empty Weight constant "a" z i (lbs) S Weight - crew o Weight - Passengers (lbs) W Weight - payload (lbs) y r Wing taper ratio g t e n m i o W e G Horizontal tail arm g l i i n Cht (volume coeff) a z T i Vertical tail arm S Cvt (volume coeff)
You cannot enter Wo! Engine power and power loading are multiplied to calculate Wo. If sizing to a range requirement, do calculation below, read Wo from graph, and select an engine that gives the desired Wo=P*P/W
1.65 Wo 1 Wing Area 4.2 0.01 6.3 0.00176 24
Cdo K (=1/piAe) W/S cruise Cr C ruise velocity Dynamic pressure L/D cruise
(ft)
(lb) (sq ft)
(ft/sec) (psf)
0.2 1.1 0.0223 0.0674 0.2 40.5 1.4 6.21
(lb/sec /bhp)
0.45 Engine SFC 0 0.75 800 Range (ft) 4860800 Breguet Exponent 0.2373 Wf/Wo 0.2310 6 Wf/Wo with allow. 0.2448 11.86 0 0 0 See Sizing Graph sheet for Wo Results 0 Wing Span Root Chord Tip Chord Mean Chord
(ft)
13.5 0.2 0.22
10 Tail areas: 0.6 Sh Sht (horizontal) 10 0.04 Sv Svt (vertical)
(ft) (ft) (ft) (ft)
2.59 0.82 0.00 0.55
(sq ft)
0.03
(sq ft)
0.01
r Homebuilders
Enter items in blue and purple. Come back and re-enter purple items after the drawing is analyzed. Send problems & questions to SADFH@aircraftdesi
e legal notice for further restrictions. airplane, in case it gets messed up!
Other Factors Used (OK to change these if you know what you are doing)
Equations (from book)
Misc Useful Calcs
1
q= ρV 2
2
Stall
W = qC L S
C D0 =C fe e (Oswald) Wcruise/Wo
0.75 0.98
K =
S wet S ref
1 0.75 π
L = D qC D0 W / S
A
=
0.424
A
CL-cruise
0.15
1
W / S
K q − R c bh p
Non-cruise weight allowance Empty Weight exponent
0.98
W f / W 0 =1 − 0.975 e
-0.09
W E / W 0 =aW −0 . 0 9 0
W 0 =
W people W payload 1− W E / W 0 −W F / W 0
Preliminary tail sizing using these methods does not guarantee that the aircraft will be stable, controllable, or safe. You must perform stability calculations after doing your design layout!
50 0 η p
L / D
Fuel Weight Fuel Vol
0.1 (lbs) 0.0 (gal)
n.com
Sizing Calculations Wo guess 1000 1500 2000 2500
We/Wo 6.3692 6.1410 5.9840 5.8650
We Wo calculated 6369.2 0.0 9211.4 0.0 11968.0 0.0 14662.6 0.0
3000
2500 Pick Wo from graph, where the two lines cross. Enter this value below to find the minimum horsepower engine for your power loading.
If sizing graph lines do not cross, change Wo-guess values above. Enter Wo from graph (lbs) Pick engine with horsepower of at least:
2000 14286
2000
d et al u 1500 cl a C o W 1000
Now find a suitable engine of at least this horsepower and enter its power below: Power of Selected Engine: Calculated Power Loading:
120 16.67
Now go to sheet 1 and enter the power of your selected engine and the power loading calculated above in the boxes this color.
500
0 800
1000
1200
Sizing Graph
1400
1600
1800
Wo Guess
2000
2200
2400
2600
As-Drawn Performance Calculations for Simplified Aircraft Design fo Use this sheet for performance calculations after you have drawn your design and measure
Values from Sheet 1 - OK to change these here, but then link from Sheet 1 is lost Wo (lb) 0 Engine Power (hp) 2 Number of Engines 1 Engine SFC (lb/hour /bhp) 0.45 Wing Area (sq ft) 1.1 Cdo 0.0223 K (=1/piAe) 0.0674 Wing CLmax 1 Takeoff air density (slugs/ft^3) 0 e (Oswald) 0.75 Wcruise/Wo 0.98 Non-cruise weight allowance 0.98 Fuel allowance (%) 6 Weight - crew (lbs) 0 Weight - passengers (lbs) 0 Weight - payload (lbs) 0 Empty Weight (lbs) 3.1 Other Inputs Propeller Diameter (ft) Engine RPM (rev/min) Cooling Power Loss (%) Cruise Power Setting (% of SL hp) Cruise air density (slug/ft^3)
Calculated Values wing loading (W/S) (psf) stall speed (ft/sec) stall speed (kts) power loading (lb/hp) Takeoff Parameter Takeoff Groundroll (ft) Takeoff to 50 ft (ft)
Cruise Weight
(lb)
5 2700 6 62 0 Power Coefficient Cp
0.22 13.51 8.00 0.14 0.0 -49.7 50.3
0.23
0.0018
Go to next sheet for climb, cruise, and maximum speed calculations then return here Cruise speed Cruise Prop efficiency
(kts)
180 Cruise speed (ft/sec) Cruise Advance Ratio J 0.85 Cruise q (psf) Cruise W/S (psf) Cruise L/D Wfuel (total) (lbs) Wfuel (usable) (lbs) Wfuel (cruise) (lbs) log term Range (ft)
Range
(nmi)
304.02 1.35 81.3 0.2 0.1 -3 -3 -3 0.08 -1133175
-187
r Homebuilders d its geometry.
Equations (from book)
W W S h p T . O . P . =1 . 2 1 C L m a x
L = D qC D0 W / S R=
550 η p
C bh p
1
W / S L D
ln
[
K q 0.975W 0
W 0−W f usable
]
Climb, Cruise, & Max Speed Calculations for Simplified Aircraft Des Use this sheet for performance calculations after you have drawn your design and mea
Input adjusted values Advance Propeller Total Cruise Dynamic V kts V ft/sec Ratio J Efficiency Thrust lbs Thrust lbs pressure q CL 50 84.45 0.38 0.59 5.96 3.7 6.28 100 168.9 0.75 0.8 4.04 2.51 25.1 150 253.35 1.13 0.85 2.86 1.77 56.48 200 337.8 1.5 0.82 2.07 1.28 100.42 220 371.58 1.65 0.8 1.84 1.14 121.5
CD 0.03 0.01 0 0 0
Drag lbs 0.02 0.15 0.02 0.59 0.02 1.34 0.02 2.38 0.02 2.88
sheet
Maximum & Cruise Speed 200
Column E
Column F
Column J
s bl -
m pf
g ar D r o t s ur h T
-
b mi l C
0 40
60
80
100
120
140
Velocity - kts
160
180
200
220
240
152 142 133 123 114 104 95 85 76 66 57 47 38 28 19 9
ign for Homebuilders sured its geometry.
Equations (from book)
D = qS C D0 KC 2 L
Climb (fps) 130058.34 154271.42 102409.77 -27384.02 -102334.96
W C L
cruise
−
Vv = V
=
[
S
1
2
q = ρV 2
q
T 1 − W L / D
]
Rate of Climb - Sea Level 000 500 000 500 000 500 000 500 000 500 000 500 000 500 000 500 0 40
60
80
100
120
140
Velocity - kts
160
180
200
220
240
Weight Reporting Format for Simplified Aircraft Design for Homebuilders Use this sheet for reporting weights calculations & estimating center of gravity.
Input only items i
(Sorry, no weights estimation methods here, just the form to enter your estimates. Moments & cg are calculated) Weight
Loc
lbs STRUCTURES Wing
ft
661.0
Moment 5600
Loc
lbs EQUIPMENT
ft
69.0
Moment ft-lbs 429
6.5
1794
Flight Controls
10
5.5
55
Horizontal Tail
24 21.0
504
Instruments
10
5.5
55
Vertical Tail
18 19.0
342
Hydraulics
2
6.0
12
Ventral Tail
276
Weight
ft-lbs
136
Electrical
12
6.0
72
155
9.0
1395
Avionics
15
5.0
75
Canopy
15
8.0
120
Air Conditioning
Nacelle on wing
50
9.0
450
Anti-Icing
Nacelle/cowling
30
7.5
225
Furnishings & Equipment
Motor Mount
10
7.5
75
Fuselage
8 17.0
Main Landing Gear
56
9.0
504
Nose Landing Gear
19
2.9
55
PROPULSION Engine
411.0
(% We Allowance) Empty Weight Allowance
2877 TOTAL WEIGHT EMPTY
0 0 20
8.0
160
114.1
7.8
891
1255.1
7.8
9797
0.0
8.0
0
10
340
7.0
2380
Air Induction
3
7.0
21 USEFUL LOAD
Cooling
3
7.0
21
Crew
Exhaust
8
7.0
56
Fuel
738.9
7.5
5542
Engine Controls
2
7.0
14
Oil
6
5.0
30
Misc. Engine Inst
5
7.0
35
Passengers
0
8.0
0
Propeller
30
7.0
210
Payload
0 10.0
0
Starter
10
7.0
70
Fuel System
10
7.0
70 T AKEOFF GROSS WEIGHT
2000 .0
7.7
15368
Crew+Pass+Pld, No Fuel
1261.1
7.8
9827
Crew+Pass,No Pld,No Fuel
1261.1
7.8
9827
Crew only, No Fuel
1261.1
7.8
9827
Crew only, Full Fuel
2000.0
7.7
15368
s n e g o l i t b i n i i s d d s a n o o o P L C
744.9
enter % don’t enter these
Calculated Empty Wei Initial Sizing Inputs sh purple box: Don't enter this! It is calc
blue
ht constant "a". Go to et and revise value in
1.2438
lated from Wo, We, and other Useful Load Group items
ASPECT RATIO OPTIMIZATION: DR-4 A-baseline Wo Wwing-base We-base
6.3 0.2 276
Read performance results and enter here
1255.1
A A/Abase 6 0.95 6.3 1.00 14 2.22
Wwing/ Ww-base Delta We We-new 0.97 -8 1247 1.00 0 1255 1.61 170 1425
Enter delta on Weight sheet (I stuck it in the unused Anti-Ice entry), and change aspect ratio and empty weight "a" factor on Initial Sizing Sheet
Range 1165 964 760
Max Cruise Speed Speed 212 175 220 180 221 181
ROC 2200 2400 2500
Aspect Ratio Trade Study 2500 2000 m pf r
Column F Column L Column M Column I
1500
o , st k 1000 ,i
m n
500 0 6
8
10 Aspect Ratio
12
max*10 cruise*10 2120 1750 2200 1800 2210 1810
14
