From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [LML] Gear-door electromagnets
To: lml
Date: Mon, 29 Jan 2007 09:37:45 -0500
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Posted for Jarrett & Heidi Johnson <hjjohnson@sasktel.net>:

  Paul, have you since swung your compass? I'd be a bit leery of any type of
magnet on my plane, at least ones that aren't originally intended to be there.
  Anyother fix is to build the door in a warped condition, warped so that the
rear of the door comes into contact [closed] before the front does, I'd think
having it warped 1/4" or more wouldn't be excessive.
  
  Jarrett Johnson
  235/320 55% [and holding for now]

"""
   The nose gear door on my 235 is operated at the very front. The rear end of
it was hanging open slightly due to aero pressures. I tried a permanent magnet
and pole piece but that wasn't doing the job, Todd Ealand, who was building
his now-completed "Lionheart" and I discussed the use of magnets since he was
installing very large inner gear-doors on his plane. He told me of a supplier
of various sizes of electromagnets  which he obtained to hold his shut. I
ordered two different sizes, and the one I chose works like a charm. I tied it
into the gear electrics so that it is only operated when the gear retracts; it
draws less than 1 Amp. I can't remember off-hand how this was done or who the
supplier is, but I can find out. Just the electromagnet in the wheel well wall
(say that fast!) and a pole piece on the door with less than a .005" gap when
closed to suck it shut!
"""