N33RB Update from 2000
2000 Beartracks Mailbag: Q&A with Bob
1999 Builder Updates
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″.
Fabric Covering the Bearhawk Cabin
Sun N’ Fun 1999
Bob’s Method for Cowl Construction
Use Loc-Tite for Preliminary Fit of Aileron and Flap Hinge Rod Ends
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!