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"GWS Beaver"

GWS kit

Specifications

Wingspan 1 Metre (40 inches)
Wing Loading 19g/dm2 (6.3 oz/sqft)
Flying Weight 370g (13oz)
CG (percent of MAC) 31% (53mm from LE)
Motor GWS EM300 (Mabuchi RK370), 5.33:1 gearbox
Propeller GWS 10 x 8
Speed Control 10A with BEC and brake
Battery 6 x Sanyo 720mAh AAA NiMH (7.2V)
Receiver GWS Naro 6 channel FM
Servos 2 x GWS Naro
Controls 3 channels:- Rudder (±15°), Elevator (±10°), Motor
Construction Molded Polystyrene Foam and Depron

strut.jpg Yet another neat kit from GWS, with a lightweight injection-molded expanded polystyrene foam body, and depron wings and tail. The kit is very complete, with all the required accessories being provided, including glue! Construction took only a few evenings. I built it stock except for turning the wing strut holders 90, and retiming the motor for reverse operation. As built, it was a wee bit nose-heavy. Rather than trying to adjust the CG by repositioning the battery, I simply taped a 5 cent coin to the rear end.

Static motor testing showed current draw was over 6A, which is pushing the 720mAh NiMH cells quite hard. I was worried that battery voltage would drop too low causing premature motor cutoff. However, in practice the cells are holding up OK, and 10 to 12 minute flights are common.

On the maiden flight wind direction forced me to take off across the 'runway' (cricket pitch), a distance of only about 2 metres. This was not a problem as with full power it leapt off the ground and climbed out strongly. Apart from being very sensitive to rudder, it handled well. Subsequently I toned the rudder throw down, and now it is very relaxing to fly.

bv3.jpg The Beaver's undercambered wing and light loading contribute to a low stall speed and good handling at high angle-of-attack. At high speed the wing flutters a bit which is disconcerting, but doesn't seem to cause any harm (for aerobatic flying GWS recommends strengthening the wing with strapping tape). The fat cowl and other scale details cause high drag, so it needs full power to loop, and glides at a steep angle. When landing it is best to keep the motor running until touchdown. The wheels don't look very scale, but they work well, even in long grass. Ground handling is excellent and the plane tracks straight on takeoff.


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