Thread Tools
Dec 08, 2016, 03:06 PM
SpitNut
Thread OP
Discussion

Hangar 9 30 cc Spitfire ARF - flap problems


I suspect others are having these problems with the flaps: Have your small control "horns" attached to the flaps snapped off? How do you fix them? Or, how do you strengthen them first so they do not snap? The geometrical relationship of the flap servo arm to the flap control horn results in a significant angle, and not a straight line. How do you deal with the resulting angled flap pushrods especially at their connecting points to the flaps? What connectors/clevises do you use? Any tips or advice would be very welcome as I've already ruined one wing and flap. Thanks, Bill
Sign up now
to remove ads between posts
Dec 08, 2016, 08:20 PM
Official Boat Bum
Eddie P's Avatar
Bill go ahead and post this in the Spitfire thread and we can work from there. Get your phone, take sime photos and we can help based on what angles you are working with. You can also see what we have done in the photo banks.
Dec 09, 2016, 09:12 AM
Build to fly, fly to fix
I thought i was the only cursed one! Mine snapped off after all the hinges were installed too. Had to do some delicate surgery to cut the hinges and then make a new horn out out of CF plate and then epoxy it back in place. Wasn't terribly difficult job, just tedious.
Dec 09, 2016, 09:55 AM
SpitNut
Thread OP
I have already gone ahead in converting both flaps to external linkages, like the ailerons, but am not really happy with the results so far. I have had on backorder for some time two new wings so I can tackle once again installing the flaps internally, but I want to have in advance answers to my problems by others more experienced than I. Hence my posted questions. Regrettably I have no pictures to post to illustrate my questions until the new wings arrive. Sorry!
Dec 09, 2016, 01:16 PM
SpitNut
Thread OP
teckbot: I am more than curious as to why your flap horn also snapped. My belief is that the relationship of the servo arm orientation and the rod attachment hole to the flap horn attachment point causes the rod to come in at a significant angle, thus also causing binding so severe at the flap horn attachment point that the horn snaps. IOW the line between the servo arm and the flap horn is NOT straight. Do you agree or disagree with that analysis? I used Sullivan gold clevises at the flap horn attachment point and I now believe that was a serious error as they did not fit well into the flap horn's hole. Maybe I should be using a different connector that will mitigate the angle problem. But what type? Any thoughts? Thanks. Bill
Dec 09, 2016, 06:06 PM
Build to fly, fly to fix
Bill, i will take the blame for breaking the control horn. I did not take enough care in pre adjusting the servo travel for the flap and over stressed it - and snapped. Next time i will not connect the clevis to the horns, see/adjust the travel first and then fine tune it in place.
Dec 09, 2016, 06:33 PM
SpitNut
Thread OP
Thanks. Maybe that was my simple mistake also, and I should stop obsessing about rod angles, etc. To reduce that angle, maybe move rod to the inner-most servo arm hole? Thanks, Bill


Quick Reply
Message:

Thread Tools