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SFG´s History
(Article and pictures by Mr. Manuel Santos from Mexico)
In April 2008 a friend of me ( Juan Carlos de la Parra, that has built planes with me ) and I ,came up with the idea of helping my plane to compensate the thin air and the altitude, (I fly at 8000 Feet over sea level ), at this altitude the planes had a tendency to stall faster than on sea level and you required more inputs on the surface to make the same effect...
we experiment last year with the SFG attached on the wing tips with great results in any maneuvers which required lateral area.
We built the plane and the SFG´s as light as we can ,to compensate the lost of powers, but for helping the side forces and the stall effect, we decided to incorporate Slats on the tip of the wing with different air foil than on the root to make the tip to stall later... also a very important benefit for me is that it will slow the roll rate of the plane giving me the time that I need to control the plane at faster roll rates, but without decreasing the deflection on the ailerons to get control at hover, also it increases the wing area and make the tail moment a little further, giving me less wing rocking and more tracking on the plane.
Adding almost 400 Sq. In. of side area with the SFG and locate them in front of the CG help me to raise the nose and to give less amount of rudder deflection, making less % of coupling mixes and getting more lift on lateral maneuvers.. we also gave .6 negative degrees on the wing to help the plane not to drop to much in inverted and keeping the CG not that far back to get more precision on the maneuvers, without losing 3D capability at all...
We have to deal with weight, it is not good to have weight on the tips of the wing. To compensate the inertia you need to break the roll and to stop it, we built them open frame with carbon fiber reinforcement so we can keep them light, adding just 29 grams on each SFG.
Over all I can say we get our goal and the plane definitely is unbelievable! it just react as I want and I can say it fly great, better than I speck...
the plane is 35 1/2 Pounds.
I want to thanks Mark Leseberg and Jason Shulman for the help they gave me when I talked about this...
Mr. Manuel Santos, multiple XFC participant.
SFG and other aerodynamic devices on F3P planes.
F3P aeromusical and specially pattern planes are extremely good environment to test new aerodynamic ideas. Low cost of main material depron allow us to test any ideas very quickly, besides this depron is very easy to work with.
Here you can see my 2011 season F3P planes, on the left Arrow is used for freestyle (aeromusical) competitions, plane have to be very agile and still be able to perform some smooth and graceful maneuvers to calm music, small SFG's on wing tips allow me to do this, it slow down crazy roll speed, and give advantage in integrated circles.
As you can see plane on the right (Symmetirc), use much more aerodynamic devices, and have more SFG's, brakes and bigger side area. All this build to achieve pleasant flying characteristics, modern F3P sequences are getting more and more difficult providing many maneuvers with integrated rolls, knife edge square loops and so on. From my competition experience i can say when plane fly constant speed in up lines and down lines, always fly smooth and don't rush judges have more time to score and usually you receive more points for that. When we compare plane without SFG and other aerodynamic devices, with plane that have them, you can see obvious differences in knife edge flight. In both cases good pilot can fly planes on same altitude (center of gravity stay in same place), but with SFG you need less up rudder to keep plane in same altitude and angle of fuselage don't change so much, while at same time plane without any "aerodynamic device help", change fuselage angle more noticeably. This can be seen on integrated circles, point rolls and simple knife edge flight. Such small things for average judge can give impression of altitude change and not precise control, this can harm pilot in hi level competitions.
SFG and other aerodynamic devices on F3A planes.
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