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Old Dec 30, 2009, 04:14 PM
nsg
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Yardley, PA
Joined Sep 2006
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GWS Beaver, flat bottom airfoil, ailerons

I built a GWS Beaver as an aileron trainer for my son. Some of the mods may be of use to other people, so here goes. The flat bottom foil mod in particular
1) may be adapted to other similar wings
2) could be produced by GWS as an upgrade kit.

The power system is an $5 HC motor, 1000 kV, 14A max, GWS HD9050, TowerPro 12A ESC, Zippy FlightMax 1300 mah. HXT-900 for the tail, HXT-500 for ailerons. The max power is around 150 wt, AUW 510g, incl. 20g ballast in the cowl.

The flight performance is where I think it should be for an advanced trainer. It slows down nicely, but can go pretty fast (for a beaver, anyway).

Picture: after maiden. Note the Formosa II wheels (still dirty, it was kind of muddy at the field), CF strips reinforcing the stab and the fin.
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Last edited by nsg; Jan 01, 2010 at 10:18 PM. Reason: changed prop to GWS HD, much better
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Old Dec 30, 2009, 04:17 PM
nsg
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Yardley, PA
Joined Sep 2006
4,169 Posts
Pictures of the wing. Note the spar. It's a balsa 10x10 spar, with thin strips of CF glued on each side. The result is reasonably light, but very stiff. The wing is set up for about 15mm dihedral, so the plane is still stable, but the ailerons are (reasonably) effective. I used balsa aileron strip for ailerons, leftovers from a crashed 60" wing. The bottom surface is 1mm depron. The CF strip in front is 1x5mm, for extra stiffness and to maintain dihedral (glued at an angle to leading edge, that forces the wing halves up a bit). The finished wing weights 110g, could be made less with lighter ailerons and less CF.
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Last edited by nsg; Dec 30, 2009 at 04:30 PM.
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Old Dec 30, 2009, 04:28 PM
nsg
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Yardley, PA
Joined Sep 2006
4,169 Posts
Flight performance:

- Overall, nice but not too nice - it's possible to have it bite you, but you'd have to really earn that.
- The LG wire is too flexible, typical for older GWS kits. I'll need to replace it.
- Required about 20g ballast in the cowl.
- The ailerons are effective, but not as powerful as on an e.g. Formosa II - just right, basically. I went for larger than scale ailerons. I think I could make them scale and still have reasonable performance. The deflection is 15mm either way.
- The elevator is too effective. I flew on low rates, and will need to turn it down more. The low rate is 12mm deflection, will reset to 12 max and 6mm for low.
- The rudder is just right, 23mm deflection at the widest point.

All in all, a success.
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Old Dec 30, 2009, 10:19 PM
Registered User
Taipei, Taiwan
Joined Oct 2005
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Well done ! Nsg
GWS Beaver II will be solid wing, longer span and with ailerons. Hopefully, Boss could make up his mind earlier.

Chen
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Old Dec 31, 2009, 01:14 PM
nsg
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Yardley, PA
Joined Sep 2006
4,169 Posts
Chen - that's good news. If the moulds aren't done yet, try to provide a scale flaps option, similar to GWS-40. Even a solid wing upgrade for the current beaver would be great.
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Old Jan 01, 2010, 12:15 AM
Erk
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Vallejo CA
Joined Nov 2005
597 Posts
Quote:
Originally Posted by nsg View Post
Even a solid wing upgrade for the current beaver would be great.

Nice mod, and great suggestion.

I too would like a full profile wing with ailerons for the Beaver.
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