Item 0905
DESIGN: UniCopter ~
Dimension, Area & Drag - Drag - In Sideslip
Reference:
DESIGN: UniCopter ~ Dimension, Area & Drag - View - Side, X-Z plane
Notes:
To try to determine the lateral static stability.
Rough Calculation of
Moment about the Z-axis:|
|
|
Area: |
Drag Coefficient |
Equivalent Flat Plate Area: |
Arm: |
Area x Arm: |
|
|
Canopy nose |
2 ft2 |
0.5 |
1 ft2 |
+2.75 ft. |
+2.75 ft2 - ft. |
|
|
Canopy w/ doors |
12 ft2 |
0.8 |
9.6 ft2 |
+1.5 ft. |
+14.4 ft2 - ft. |
|
|
Rear Fuselage |
5.2 ft2 |
0.7 |
3.64 ft2 |
-0.8 ft. |
-2.9 ft2 - ft. |
|
|
Boom ~ 4 ft2 x 2 |
8 ft2 |
0.6 |
4.8 ft2 |
--5.5 ft. |
-26.4 ft2 - ft. |
|
|
V. Stab. ~ 4.1 ft2 x 2 |
8.2 ft2 |
2.0 |
16.4 ft2 |
-9.5 ft. |
-155.8 ft2 - ft. |
|
|
|
|
|
|
Resultant: |
-168.0 ft2 - ft. |
Rough Calculation of
Moment about the X-axis: (for-aft axis through center of rotors)|
|
|
Area: |
Drag Coefficient |
Equivalent Flat Plate Area: |
Arm: |
Area x Arm: |
|
|
Canopy nose |
2 ft2 |
0.5 |
1 ft2 |
+3.75 ft. |
+3.75 ft2 - ft. |
|
|
Canopy w/ doors |
12 ft2 |
0.8 |
9.6 ft2 |
+2.2 ft. |
+21.1 ft2 - ft. |
|
|
Rear Fuselage |
5.2 ft2 |
0.7 |
3.64 ft2 |
+2.0 ft. |
+7.3 ft2 - ft. |
|
|
Boom ~ 4 ft2 x 2 |
8 ft2 |
0.6 |
4.8 ft2 |
+0.5 ft. |
+2.4 ft2 - ft. |
|
|
V. Stab. ~ 4.1 ft2 x 2 |
8.2 ft2 |
2.0 |
16.4 ft2 |
-1.0 ft. |
-16.4 ft2 - ft. |
|
|
|
|
|
|
Resultant: |
+18.5 ft2 - ft. |
The fact that the fuselage and boom have more drag then the vertical stabilizer will give instability. The CofG will be 24.5" - ((18.5/35.44)*12)" (approx.) = 18.2" below the vertical center of drag. This should have a positive effect. The horizontal stabilizer will act as a winglet on the vertical stabilizer and this may also help.
Fuselage:
xxx
Landing Gear:
xxx
Horizontal Stabilizer:
xxx
Vertical Stabilizer:
xxx
Main Rotors:
xxx
Vectored Exhaust & Cooling:
No effect during autorotation.xxx
Total Equivalent Flat Plate Area:
xxx
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Last Revised: July 4, 2004