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Building Tips and technical articles. => Building techniques => Topic started by: Paul Allen on August 25, 2009, 08:00:41 PM

Title: Replacing a flap horn.
Post by: Paul Allen on August 25, 2009, 08:00:41 PM

Having retired my Oriental a while ago ( 13 years service),after I found the control
system worn out, I never thought I would need to fly it again.Had plans to finish the
Brodak Smoothie and have it trimmed out for a local Classsic comp coming up,but that
passtime ( work) seems to have got in the way,so what to do?
Replace the flap horn leg,this is what I did,see photo's.

Title: Re: Replacing a flap horn.
Post by: Paul Allen on August 25, 2009, 08:08:15 PM

Made up a new horn plate from 1.5 mm steel plate,bushed with 1/8'' OD brass tube
bolted new plate to old one with 2/56 bolts and JB weld,pushrods will have 3/32"
wheel collars fitted with a spot of Loctite on the grub screws.

Title: Re: Replacing a flap horn.
Post by: john e. holliday on August 26, 2009, 09:06:35 AM

Looks like a great solution to the problem.  DOC Holliday

Title: Re: Replacing a flap horn.
Post by: Randy Powell on August 26, 2009, 09:18:49 AM

Necessity is the mother ...

Title: Re: Replacing a flap horn.
Post by: Dennis Adamisin on August 26, 2009, 10:02:32 AM

NICE piece of work, Paul!  I would estimate at least another 13 years of service from the Oriental.  Your new installation actually looks superior to the original(?)

Title: Re: Replacing a flap horn.
Post by: Ralph Wenzel (d) on August 26, 2009, 10:33:33 AM

Creative approach to solving a problem. However, I don't see any bushing tubing in the new installation. Another 13 years, and you'll have to rebuild the control system again. (I should have a plane last so long . . . .)

Title: Re: Replacing a flap horn.
Post by: Paul Allen on August 27, 2009, 02:54:25 PM

Ralph
        It has two bushings but they are only 1/8" long as the push rod was
retained by soldered washers,but the use of the wheel collars, set the length of
the bushes,they are on the opposite side to the one in the photo.
Glued in two balsa blocks to act as a safety so the pushrods cannot come out
in the event of a collar coming loose.

Title: Re: Replacing a flap horn.
Post by: Ralph Wenzel (d) on August 27, 2009, 05:43:03 PM

Got it, Paul. I can see the copper tubing in the 3rd photo. Should have enlarged it the first time.