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Building Tips and technical articles. => Building techniques => Topic started by: Leester on June 05, 2006, 03:04:28 AM

Title: Flap hook up to angled hingeline
Post by: Leester on June 05, 2006, 03:04:28 AM: How do you make a bell crank to flap hook up when the flap hinge line is angled not at 90 deg. to the fusalage? ??? ??? ??? ??? ??? ??? n~ n~ n~ f~ j1 j1 j1 j1
Title: Re: Flap hook up to angled hingeline
Post by: RC Storick on June 05, 2006, 11:25:16 AM: You need to make LUCKY BOXES. A lucky box is just what is sounds like , a box that allows the control horn to float. Maybe someone can post a picture. I have not made any in long time.
Title: Re: Flap hook up to angled hingeline
Post by: Tom Dugan on June 05, 2006, 12:33:12 PM: Lee,

I remembered an earlier discussion about this on SSW. Try this thread http://www.clstunt.com/htdocs/dcforum/DCForumID1/18227.html

Thomas
Title: Re: Flap hook up to angled hingeline
Post by: Leester on June 05, 2006, 01:06:22 PM: Thanks Robert and Thomas, I am familier with Lucky boxes and the link told me what I needed to know on using them in this instance.
Title: Re: Flap hook up to angled hingeline
Post by: rustler on June 05, 2006, 01:24:21 PM: I like Robert's idea of posting a picture. I could instal these successfully, but am not sure if I'd be doing it as designed. Can anyone post a pic. showing a spanwise cross-section through a Lucky Box? My way would end up with quite a thick flap, possibly thicker than really desired.
Title: Re: Flap hook up to angled hingeline
Post by: Bill Little on June 05, 2006, 01:37:51 PM: Quote from: Leester on June 05, 2006, 03:04:28 AM
How do you make a bell crank to flap hook up when the flap hinge line is angled not at 90 deg. to the fusalage? ??? ??? ??? ??? ??? ??? n~ n~ n~ f~ j1 j1 j1 j1

Actually, on some of the swept forward TE designs, nothing unusual is done to the flap horn. An example is th e'59 Ares as built by Bill Werwage. On his video he shows how to install a flap horn with nothing changed.

Bill <><
Title: Re: Flap hook up to angled hingeline
Post by: Leester on June 05, 2006, 02:32:08 PM: Thanks Bill: If your talking the I Beam video I've got that I'll check it out.
Title: Re: Flap hook up to angled hingeline
Post by: Leester on June 06, 2006, 03:18:59 PM: Ty: I just checked my Brodak plans and I see what you are saying. Thanks
Title: Re: Flap hook up to angled hingeline
Post by: Bill Little on June 08, 2006, 05:59:58 AM: Quote from: Rudderless on June 06, 2006, 02:55:29 PM
Umm, there is one thing that must be done. A section the length of the horn supports must be made parallel to the main spar. In other words it must be cut straight and not left with the angles. This is shown on the '59 Ares plans. Don't do it and fly like I did, all free flight in the overheads, Oh what fun. n~ The horn gets spring loaded and keeps going back to neutral.

Hi Ty,

Check out how Mr. Rabe does his horns now. He has replaced his split horns with a single horn lashed to the TE.

Bill <><
Title: Re: Flap hook up to angled hingeline
Post by: Leester on June 08, 2006, 01:07:24 PM: Bill : Where can one check this out at ? ??? ??? ???
Title: Re: Flap hook up to angled hingeline
Post by: Bill Little on June 09, 2006, 07:14:32 AM: Quote from: Rudderless on June 08, 2006, 02:26:58 PM
Yes lashed. With what is that yellow stuff?? It ain't carbon fiber thread. Also he did cut the TE straight at that point, right? Then the angle of the TE will not affect the horns action and the lucky boxes make it all work. Heck, when I first heard of lucky boxes, I assumed it had to do with craps in Vegas. ;D

Talking to Al, I don't remember him saying anything about shaving the TE straight, Keith Trostle, either. Just bend the horns around the TE. I'll check with Al, got to do a Classic Bearcat horn very soon.

Don't need no stinkin' lucky boxes. ::) ;D ~^ **) **) x: f~
Title: Re: Flap hook up to angled hingeline
Post by: Bill Little on June 09, 2006, 07:16:37 AM: Quote from: Rudderless on June 08, 2006, 02:26:58 PM
Yes lashed. With what is that yellow stuff?? It ain't carbon fiber thread. Also he did cut the TE straight at that point, right? Then the angle of the TE will not affect the horns action and the lucky boxes make it all work. Heck, when I first heard of lucky boxes, I assumed it had to do with craps in Vegas. ;D

I have some KEVLAR thread that is yellow like that.
Title: Re: Flap hook up to angled hingeline
Post by: Bill Little on June 09, 2006, 07:02:47 PM: I just remembered a conversation with Bill Swarez about his P-38 and it's swept forward trailing edge. He drills the hole for the flap horn then moves the bit in an arc from side to side without increasing the size of the entrance hole. This creates a slot in the flap that is an arc.. Soak it with thin CA to stiffen it up.
Title: Re: Flap hook up to angled hingeline
Post by: phil c on June 11, 2006, 06:53:01 PM: It helps too to bend the flap horn "ears" so they are perpendicular to the flap hing line. Do this greatly reduces the amount the ears go out of plane when the horn moves. If you fill the holes in the flap with silcon glue you get a solid working flap with no play or sticky spots.
Title: Re: Flap hook up to angled hingeline
Post by: Leester on June 11, 2006, 08:31:24 PM: Thanks guys for all the help. I just about have it done, it's all pieced together and it even works. Just have to tweek the flaps a little and it's all set. When I get film developed I'll show some pics.