Design Check Report
|
Design Name: |
Goomie |
|
Designer: |
DPM Botes |
|
Design Date: |
Dec 2007 |
Gross Weight Check
|
Parameter |
SI Units |
User Units |
|
Design Gross Weight |
650. kg |
650. kg |
|
As-Drawn Gross Weight |
622.4 kg |
622.4 kg |
|
Percent Difference |
38.31 |
|
Aircraft design gross weight and as-drawn gross weight are considerably different. Design weight should be adjusted and significant sizing adjustments to the aircraft's components will probably be required to achieve appropriate proportions and power.
CG Limit Check
|
Parameter |
SI Units |
User Units |
|
Forward CG Limit |
2.547 m |
2.547 m |
|
Aft CG Limit |
2.839 m |
2.839 m |
|
Neutral Point |
2.997 m |
2.997 m |
|
Forward CG Loading |
2.397 m |
2.397 m |
|
Aft CG Loading |
2.655 m |
2.655 m |
|
Rotation Speed at Forward CG Loading |
31.61 m/s |
61.4 knots |
|
Rotation Speed at Aft CG Loading |
23.46 m/s |
45.57 knots |
The aircraft can be loaded such that the CG is forward of the forward CG limit. This could lead to unsafe operation. Care should be taken to ensure that the CG is within range for normal operational loading conditions.
The rotation speed for the design is higher than usually recommended. This means the elevator may not have sufficient control authority to lift the aircraft's nose during takeoff. It is recommended that the elevator be sized so that the nose can be rotated at 80% of the takeoff speed, which is 39.6 knots for this design.
Propeller #1 Clearance Check
|
Parameter |
SI Units |
User Units |
|
Level Clearance |
0.7397 m |
0.7397 m |
|
Tail Down Clearance |
0.3586 m |
0.3586 m |
View Angle Check
|
Parameter |
SI Units |
User Units |
|
Level View Angle |
0.5706 rad |
32.69 deg |
|
Tail Down View Angle |
0.343 rad |
19.65 deg |
Tail Clearance Check
|
Parameter |
SI Units |
User Units |
|
Tail Clearance Angle |
0.587 rad |
33.63 deg |
|
Flare Angle |
0.2276 rad |
13.04 deg |
Stabilizer Size and Location Check
|
Parameter |
SI Units |
User Units |
|
Vertical Stabilizer Volume Coefficient |
0.0202 |
|
|
Canard Volume Coefficient |
0.2396 |
|
|
Angle between Wing and Canard |
-0.4693 rad |
-26.89 deg |
Canard volume coefficienct is lower than historical averages. You may need to increase stabilizer size. Usual range = 0.3 -- 0.7.
Power and Wing Loading Check
|
Parameter |
SI Units |
User Units |
|
Power Loading |
0.005029 kg/watts |
5.029 kg/kW |
|
Wing Loading |
36.06 kg/m^2 |
36.06 kg/m^2 |
Power loading is below historical averages. Design may be overpowered.
Landing Gear Geometry Check
|
Parameter |
SI Units |
User Units |
|
Forward CG Gear Angle |
0.3673 rad |
21.04 deg |
|
Aft CG Gear Angle |
0.1708 rad |
9.787 deg |
|
Track Angle |
0.6283 rad |
36. deg |
|
Overturn Angle |
0.6292 rad |
36.05 deg |
|
Min Main Gear Weight Fraction (%) |
78.73 |
|
|
Max Main Gear Weight Fraction (%) |
90.46 |
|
Aft CG position is too far aft relative to main gear. The aircraft may have a tendency to sit on its tail. The aft CG gear angle should be greater than the tail clearance angle (33.63 deg) or the flare angle 3 degrees (16.04 deg) whichever is smaller.
The nose gear is carrying too much of the aircraft weight. Rotation may be difficult at takeoff. The main gear weight fraction should be at least 85%.
Performance Check
|
Parameter |
SI Units |
User Units |
|
Cruise Speed |
68.43 m/s |
132.9 knots |
|
Target Cruise Speed |
61.78 m/s |
120. knots |
|
Stall Speed |
18.53 m/s |
36. knots |
|
Target Stall Speed |
23.17 m/s |
45. knots |
|
Max Rate of Climb |
10.13 m/s |
1,994.9 fpm |
|
Target Max Rate of Climb |
10.16 m/s |
2,000. fpm |
|
Range at Cruise |
1.793e 06 m |
968.1 nmi |
|
Target Range at Cruise |
7.408e 05 m |
400. nmi |
|
Cruise Pitch Attitude |
-0.02685 rad |
-1.539 deg |
|
Cruise Elevator Setting |
-0.01457 rad |
-0.8348 deg |
The stall speed was outside the analysis range. You can increase the analysis speed range by decreasing the target stall speed.
The design as drawn does not meet the max rate of climb criteria. Ways to improve rate of climb include increasing power, increasing aspect ratio, and decreasing wing loading.
Size Check
|
Parameter |
SI Units |
User Units |
|
Wing Span |
6.4 m |
6.4 m |
|
Tail Height |
1.591 m |
1.591 m |
|
Propeller #1 Height |
2.126 m |
2.126 m |
CG Limits Calculation Report
|
Design Name: |
Goomie |
|
Designer: |
Dawie Botes |
|
Design Date: |
Dec 2007 |
CG Limits Breakdown
Aft Limit Calculation
|
Parameter |
SI Units |
User Units |
|
Aircraft Speed |
61.78 m/s |
120. knots |
|
Pitch Attitude |
0.0 rad |
0.0 deg |
|
Elevator Deflection |
0.0 rad |
0.0 deg |
|
Reference Long CG |
2.655 m |
2.655 m |
|
Component |
Ref Area Ratio |
Ref Chord Ratio |
Lift Curve Slope |
Aerodynamic Center |
Moment Curve Slope (about GW CG) |
|
m |
|||||
|
Main Wing |
1. |
1. |
3.533 |
3.528 |
-1.412 |
|
Canard |
0.2665 |
0.3458 |
4.313 |
1.775 |
5.517 |
|
Vertical Stabilizer |
0.1058 |
0.3455 |
1.56e-06 |
4.751 |
-3.947e-06 |
|
Fuselage |
0.07691 |
2.202 |
1.155 |
0.8873 |
0.4681 |
|
Parameter |
SI Units |
User Units |
|
Neutral Point |
2.997 m |
2.997 m |
|
Aft Limit |
2.839 m |
2.839 m |
Forward Limit Calculation
|
Parameter |
SI Units |
User Units |
|
Aircraft Speed |
19.49 m/s |
37.86 knots |
|
Pitch Attitude |
0.3103 rad |
17.78 deg |
|
Elevator Deflection |
0.5236 rad |
30. deg |
|
Flaps Deflection |
0.7854 rad |
45. deg |
|
Reference Long CG |
2.655 m |
2.655 m |
|
Component |
Ref Area Ratio |
Ref Chord Ratio |
Angle of Attack |
Lift Coefficient |
Aerodynamic Center |
Moment Coefficient |
|
deg |
m |
|||||
|
Main Wing |
1. |
1. |
12.18 |
0.7728 |
3.528 |
-0.2394 |
|
Canard |
0.2665 |
0.3458 |
14.53 |
2.701 |
1.775 |
3.191 |
|
Vertical Stabilizer |
0.1058 |
0.3455 |
6.025e-06 |
0.0 |
4.751 |
0.0 |
|
Fuselage |
0.07691 |
2.202 |
0.0 |
0.3585 |
0.8873 |
0.1452 |
|
Parameter |
SI Units |
User Units |
|
Forward Limit |
2.547 m |
2.547 m |
Weight and Balance Report
|
Design Name: |
Goomie |
|
Designer: |
Dawie Botes |
|
Design Date: |
Dec 2007 |
Weight Breakdown
|
Parameter |
Weight |
Station |
||
|
SI Units |
User Units |
SI Units |
User Units |
|
|
Structures Group |
|
|
|
|
|
Main Wing |
40.24 kg |
40.24 kg |
3.843 m |
3.843 m |
|
Canard |
29.71 kg |
29.71 kg |
1.872 m |
1.872 m |
|
Vertical Stabilizer |
4.466 kg |
4.466 kg |
4.853 m |
4.853 m |
|
Fuselage |
47.15 kg |
47.15 kg |
1.752 m |
1.752 m |
|
Landing Gear |
22.82 kg |
22.82 kg |
2.295 m |
2.295 m |
|
Propulsion Group |
|
|
|
|
|
Engine #1 |
102.1 kg |
102.1 kg |
4.129 m |
4.129 m |
|
Fuel System |
12.79 kg |
12.79 kg |
3.278 m |
3.278 m |
|
Equipment Group |
|
|
|
|
|
Avionics |
22.97 kg |
22.97 kg |
0.8225 m |
0.8225 m |
|
Electrical |
29.05 kg |
29.05 kg |
0.1875 m |
0.1875 m |
|
Flight Controls |
15.22 kg |
15.22 kg |
1.752 m |
1.752 m |
|
Furnishings |
13.36 kg |
13.36 kg |
1.385 m |
1.385 m |
|
TOTAL WEIGHT EMPTY |
339.8 kg |
339.8 kg |
2.648 m |
2.648 m |
|
Useful Load Group |
|
|
|
|
|
Crew and Passengers |
163.3 kg |
163.3 kg |
2.217 m |
2.217 m |
|
Fuel |
117.3 kg |
117.3 kg |
3.278 m |
3.278 m |
|
Cargo |
2. kg |
2. kg |
3.086 m |
3.086 m |
|
AS-DRAWN GROSS WEIGHT |
622.4 kg |
622.4 kg |
2.655 m |
2.655 m |
|
DESIGN GROSS WEIGHT |
450. kg |
450. kg |
|
|
CG Limits
|
Parameter |
SI Units |
User Units |
|
Forward CG Limit |
2.547 m |
2.547 m |
|
Aft CG Limit |
2.839 m |
2.839 m |
|
Neutral Point |
2.997 m |
2.997 m |
|
Forward CG Limit (%MAC) |
-25.62 |
|
|
Aft CG Limit (%MAC) |
-10.87 |
|
|
Neutral Point (%MAC) |
-2.872 |
|
Loading Extremes
|
Parameter |
CG Location |
Static Margin |
||
|
SI Units |
User Units |
% MAC |
||
|
Most Forward CG Loading |
2.397 m |
2.397 m |
30.27 |
|
|
Most Aft CG Loading |
2.655 m |
2.655 m |
17.27 |
|