From: "Graham" <grahamn@mpx.com.au>
To: <lancair.list@olsusa.com>
Subject: Flap hinge points and gap sealing from 16 jan 99
Date: Wed, 27 Jan 1999 20:06:14 +1100
Message-ID: <000001be49d8$f613aa00$0c0082be@nuteye>
Importance: Normal
Mime-Version: 1.0

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In an effort to seal this gap and stop the presumably high pressure air
moving up through here i have taken a different approach. I moulded a 3 BID
flange at right angles to the skin on the very trailing edge of the wing and
leading edge of the flap between which I will sandwich some foam (maybe .5"
foam in a .125" gap). The flange is only as high as the width of the foam
tape (maybe 1/2"). This of course has the potential to be blown out the top.
To prevent this, the flange on the flap LE transitions to a radiused section
which curves forward over the wing flange. The radius of the curved section
is about 1/2in and keeps this slot closed throughout the flap movement and
therefore stops the foam going out the top. Haven't flown it yet but that's
my theory. It's a bit messy to build - I used timber moulding that has a
suitable radius to form the flange and the curve, super glued some timber
brackets to it to attach it at the flap hinge locations, used duct tape as a
release and painfully laid it all up inside the TE and Flap LE. Some
creative brushes bent at 90 degrees help!

I also have a flange on the fillet at the inboard end of the flap to try and
seal this gap. However to avoid overstressing this flange I need to make
sure that the flap motor stops ABSOLUTELY at the top of it's travel. I have
the torque tube flap system. I believe there was some discussion re limiting
flap travel in case of a runaway in earlier correspondence but I cant find
this. Seems we also need to stop it going bersek in the down direction.

Any ideas?? Some way of having thread slip at each end perhaps, some sort of
clutch, some means of using limit switches to absolutely disengage power at
each end.

Thanks
Graham Nutt