- Hatz CB-1-
Establishing Center of Gravity Range
by Randy Brooks, NX24B
"Bratz" CB-1 S/N535
The Hatz plans gives only the C.G. location as loaded. I established a C.G.
Range for my Bratz CB-1 as follows:
The Clark "Y" airfoil is used on the Hatz with 50 inch chord. The center of
pressure range is 18% Forward and 35% Rearward or +9.0 inches
and +17.5 inches from leading edge. Reference used is Technical
Manual T-400, Theory of Flight. I prefer to use 33% or +16.5
inches for aft center of pressure.>
- Datum --- Lower wing leading edge
- Forward C.G. --- +9.0 inches - 12.65 inches equals -3.65 inches
- Rearward C.G. --- +16.5 inches - 12.65 inches equals +3.85 inches
Procedure to Use
CLICK
HERE TO REFER TO SKETCH
- Calculate wing areas of upper & lower wings and add together.
- Use lower wing leading edge as datum.
- Divide upper wing area by total wing area equals 55% (approx.)
of total area.
- Multiply the stagger (23") by 55 % equals -12.65 inches
which locates
leading edge of the Mean Aerodynamic Chord (MAC) from lower wing
leading edge (datum).
- Forward C.G. equals 18% x 50 inches equals 9 inches aft of leading
edge of MAC.
- Rear C.G. equals 33% x 50 inches equals =16.5 inches aft of leading
edge of MAC.
- Locate forward C.G. in reference to (datum) lower wing leading
edge.
9 inches - 12.65 inches equals -3.65 inches
- Locate Rearward C.G. in reference to (datum) lower wing leading
edge.
16.5 inches - 12.65 inches equals +3.85 inches
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