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General control line discussion => Open Forum => Topic started by: Joseph Patterson on April 17, 2012, 02:32:46 PM
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I have looked back through some of the threads relating to the Joe Just/Jim Pierson UKEY stunt trainers to see if any of you guys that flew had problems with the O.B. WING flying high upright and low inverted. I asked about this a while back on the forum and got responses referring to the top mounted bell/L.O.'s above wing affected the vertical C.O.G., which I understand. We have built (3) of the JP. UKEY'S and all have needed OB tabs, However, when I looked at pictures of other UKEYS that were the JJ/JP type like ours, none that I could see had OB TABS. The wing alignment is OK- no twists or warps on our planes so what gives that yawl have no tabs, but we need gobs of tab!! TO HANDLE THE VCOG problem?
Doug
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Move the bellcrank to the bottom of the fuselage. Fabricate a new leadout guide just l;like the existing one and install it on the underside of the wing. Substitute two wheel dural loanding gear landing gear for the single peg. The probability is very high that you will be able to get rid of the tabs and the plane will fly much better/more predictably. It worked on my three Ukeys.
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One of the ways to adjust U-key's for level wings is to just crimp one or both TE's until it is as you'd like. I would use the two wheel aluminum legs and mount the BC on the bottom. H^^ Steve
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Thanks guys. We never used the single mono gear. Currently using conventional wheels with 1/8" wire. We will try the Bell crank on bottom as yawl suggest. Another thing I believe I need to do is go with shorter Landing gear- the one I made is too tall- probably could easily handle a 13" plus prop- don't know why I got carried away. I know with the tall landing gear coupled with the top mounted BC and LO could drastically affect the VCOG. Again thanks for the advice.
Doug