Hi,

Has anyone experimented with these so called side-force generators? They are vertical wings placed so that their aerodynamic centre is coincident with the longitudinal centre of gravity position. The idea behind them is to provide more lateral 'lift' when the rudder is deflected and is primarily used to improve knife edge performance.

They are placed at the CG so as not to affect the direction stability of the aircraft - i.e they produce a force, not a moment.

Anyway, I'm considering experimenting myself but was wondering if anyone could recommend a procedure for obtaining an appropriate surface area. A rule of thumb even! I know a number of shock flyer indoor type aircraft have had them (tensor shown below for example) but i'm intending to use them on a 50 sized aerobatic aircraft.

thanks m

George Hicks has done plenty of experimenting and recently wrote an article for 3D Flying mag. on SFG.

Full scale has also done a bunch ----search for non-planar wings.

"C" shapes and full circles have been proposed----not to mention SFG by fuselage shape and location of the 'wide point'. Although the non-planar shapes are about as aesthetically pleasing as bug splat.

The consideration of SFG has been around for quite some time and Pattern flyers have used it for years.

Theres a twice size tensor going about, think theres a pic in George Hicks forums.

Yeah i actually read the article by george hicks in 3D flyer magazine, but it wasn't my magazine so i forget the dimensions he suggests.

I think it was around 20 to 30% of the wing area but can't quite remember.

They DO look pretty silly but i'm still interested in using them just as an experiment.

I have played around quite a bit with side force generators. My favorite trick is to use full-chord airfoiled interplane struts on bipes that look like conventional "Z" struts, thanks to transparent covering. Have also done the same thing with cabane struts, and equipped them with controllable rudders to make them move opposite to the normal rudder, thus acting like coupled flaperons in knife edge. These vastly improved the bipe's knife-edge, cutting its knife-edge loop radius in half, and produced a nose-level, power-off knife edge glide, which I like.

Also tried putting detachable fins totalling about 20% of the wing area on the wings of a fun-fly monoplane; these were horribly ugly, and didn't improve knife edge all that much - pretty much a failure. Bipes are hard to beat in knife edge. I think that a bipe with a controllable cabane , and possibly, four controllable full chord interplane struts could be very entertaining without looking very weird.

Thanks for the reply,

I think you are right - biplanes suit the SFG layout the best, but for now i'll be experimenting with an existing monoplane design. In future i may design a proper aircraft around the SFG's as opposed to having them as add-ons. Flapped SFG's sound pretty cool too. Project for the summer methinks.

m