GWS Beaver, flat bottom airfoil, ailerons - RC Groups
Thread Tools
Dec 30, 2009, 04:14 PM
Registered User

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.
Last edited by nsg; Jan 01, 2010 at 10:18 PM. Reason: changed prop to GWS HD, much better
Sign up now
to remove ads between posts
Dec 30, 2009, 04:17 PM
Registered User
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.
Last edited by nsg; Dec 30, 2009 at 04:30 PM.
Dec 30, 2009, 04:28 PM
Registered User
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.
Dec 30, 2009, 10:19 PM
Registered User
Well done ! Nsg
GWS Beaver II will be solid wing, longer span and with ailerons. Hopefully, Boss could make up his mind earlier.

Dec 31, 2009, 01:14 PM
Registered User
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.
Jan 01, 2010, 12:15 AM
All thumbs, no scents
Erk's Avatar
Originally Posted by nsg
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.

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Flat bottom sailboats rich1833 Sailboats 17 Dec 20, 2009 01:12 PM
For Sale RTR cool little flat bottom weathervane Boats (FS/W) 2 Nov 30, 2009 03:14 PM
Question on changing the airfoil on a Micro plane. (Undercambered to flat bottom) WarpdSpazm Modeling Science 10 Jan 29, 2005 10:39 PM
flat bottom mini-max airfoil fromage Parkflyers 1 Dec 05, 2001 04:19 PM
Tiny - Flat wing bottom airfoil ? Jaymom Parkflyers 11 Apr 26, 2001 09:24 PM