2000 Barrows Fly-in Report

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1999 Weight and Balance Calculations

Source: 1999 Beartracks, Bob Barrows

*Hold this dimension for all engine installations unless weight and balance calculation problems are encountered

Bearhawk N33RB

Aft Sample Weight Arm Moment Forward Sample Weight Arm Moment
*Main Gear R 600 -1.63 -978 *Main Gear R 600 -1.63 -978
*Main Gear L 596 -1.63 -970 *Main Gear L 596 -1.63 -970
*Tail Wheel 75 199 14925 *Tail Wheel 75 199 14925
Front Seats 400 14 5600 Front Seats 200 14 2800
Cargo Area 530 57 30210 Cargo Area 0 57 0
Fuel lbs. 300 24 7200 Fuel lbs. 30 24 54
Totals 2500   55987 Totals 1500   15829
Gross Weight 2500     Gross Weight 2500    
C.G. Range 10.5″ – 22.5″     C.G. Range 10.5″ – 22.5″    
C.G. Range 16% – 34%     C.G. Range 16% – 34%    
C.G. Aft 22.4″     C.G. Forward 10.5″    
C.G. (MAC) 34%     C.G. (MAC) 16%    
Empty Weight – 1270* Empty Weight C.G. – 10.2″*

*As per weigh in of Proto II N33RB on 9-9-99

Note: Empty weight includes: 10 quarts oil, O-540 Lycoming Engine, no electrical system, no rear seats, utility door system and constant speed propeller (3-blade composite).

Forward C.G. = 15829/1501 = 10.5″     10.5/66 chord = 16%

Rear C.G. = 55987/2500 = 22.4″     22.4/66 chord = 34%

Do your first test flight with the c.g. between 13.5″ and 18.5″.

N6890R Weight and Balance

Flap Hinge Mounts: Tack Weld At First

Source: 1999 Beartracks, Bob Barrows

Refer to drawing #13. When making the flap hinge mounts it is best to just tack weld the pieces together first and not finish weld until the wing is finished and the flaps are in place. This will allow you to cut the tack welds and realign the hinge mounts if needed in order to achieve the best fit up between the flaps and wing. Once the fits are established then remove the fittings from the wing and finish welding.


Flap hinge mount as removed from welding jig, tack welded together only!