Flap Installation - RC Groups
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Oct 19, 2009, 02:51 AM
finger slicer
carpetbomb's Avatar

Flap Installation

Looking for some advice/suggestions/links/etc. to flap installation. Specifically running the linkage through the wing so you're connecting to the top of the flap and not the bottom.

Most wings have a spar of some sorts at the TE. Seems like you have to cut through it for this type of linkage install - is that normal?

Also - I know there can be a mechanical advantage for this type of install. I assume there's an aerodynamic advantage as well?

I'm going to be building a new Enigma here soon. My last one I bought used, and the flaps were mounted traditionally. I'm considering attempting going through the wing - (besides looking cool) I'm assuming there's an advantage here in energy retention? My last Enigma bled off speed pretty rapidly, so this time around - I want to minimize that much as much as possible.

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Oct 19, 2009, 07:45 AM
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Rodders's Avatar
Pages of info on here from my enigma build and others.

Oct 19, 2009, 09:33 AM
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Andy W's Avatar
V11 comes set up for this - some detail pics in my servo installation thread: https://www.rcgroups.com/forums/showthread.php?t=258351
Oct 19, 2009, 09:44 AM
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grobbins666's Avatar
Hi Mike, The TE spar is balsa and I drilled the complete diameter then reinforced with thin CA. The tricky part is keeping every thing straight and finding proper fairings. My cuts to the top skin are a little sloppy, but it was my first hollow molded build. I have seen pics of people drilling small holes through the skins, but I don't think you will be able to couple the ailerons with the flaps. Also you might want to make your own horns out CF or G10 to get 80-90 degrees. The main thing is taking your time and make sure it is straight and true.
Last edited by grobbins666; Oct 19, 2009 at 09:46 AM. Reason: punct.
Oct 19, 2009, 10:22 AM
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la528it's Avatar
Mike, if you go through the top, then when the flaps are down (encountering the most force) they will be pushing the servo instead of pulling. If you can fit the servo against the main spar, then you are not exerting pressure on the skin, but rather the spar. If your servo is too thick, you can wedge in some balsa between the spar and the servo. Regarding the trailing edge, you should not have to cut it at all, in principle, it suffices to merely cut the top skin. If this is all jiberish, give me a call tonite and I can take some pictures and try to explain.

have a good week!

P.S. this also usully allows for more flap deflection, but given that the enigma can essentially crawl with minor flap deflection, you can probably get away without it....

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