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Mar 12, 2002, 06:57 PM
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Far4nugn's Avatar

Flap to aileron mix--how much?


Hey guys, I'm setting up the flaps on my 2-meter Velvia and I'd like to hear what you use for this mix. I'm thinking 50% of aileron travel to start with, is this reasonable?

Also max flap deflection. I am not going to contests so I dont need 90, but I want an effective crow since I fly in a small field. Is 30 enough?

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Mar 12, 2002, 07:07 PM
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Gman2's Avatar
If you got 90 degrees flap then use it. 50/5 mix is good,
Mar 12, 2002, 07:47 PM
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The problem with full span aileron control is that the airfoil is constantly disturbed and rarely flying at the design point. In addition, differential forces created by ailerons are most effective at a point as far from the root of the wing as practical (highest leverage). So the inboard portion does the least good for roll and is not that good for the airfoil. This assumes that normal deflections of the aileron are greater than those used for camber adjustment. This is usually the case. So my version of a good wing has separate flap/camber and outboard ailerons. I own a Jaro Meuller "Escape"--an F3B glass ship that actually has "trilerons" a small set of tip-only ailerons outboard of the normal ailerons. This allows almost the entire wing to be "quiet" while only the far tips are used for bank. This arrangement is perfect for working light thermals.

Regards,
Q
Mar 12, 2002, 09:26 PM
Sherman Knight

How much mix


Talk about a loaded question. This is purely a pilot preference issue. I will make one comment though. Most two meter thermal duration planes have way too much control throw. So the answer is it depends on how you like to fly. Smooth and looking good or jeryky and just looking jerky. I would pick smooth over jerky any time. in other words, often, less throw is better. Personally, I find that mixing flap has little effect unless I am flying fast and want to measure roll rate in rolls per second instead of seconds per roll.

Sherman Knight
Mar 12, 2002, 10:16 PM
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Far4nugn's Avatar
Thanks. I can see how it would be mostly preference. I want more roll authority for 'showing off' ocassionally, but the ailerons alone (and a bunch of rudder) seem to be more than enough for thermal flying.

What I'm interested in is efficiency. It seems the more gradual the transition the better. If you imagine a bird's wing, it doesnt have a little square section that moves a lot when it wants to bank, there is a gradual increase in deflection from the root to the tip. This seems like it would be more efficient. Slaving flaps to ailerons is a step in this direction is it not?


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