Mailing List lml@lancaironline.net Message #11572
From: Dan Schaefer <dfs155@earthlink.net>
Subject: Flap microswitches
Date: Sun, 18 Nov 2001 23:53:05 -0800
To: Lancair list <lancair.list@olsusa.com>
         <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>
         <<  Lancair Builders' Mail List  >>
         <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>

Jim Nordin, FWIW:

Perhaps it would be better if you forgot those turkeys (the magnetic flap
limit seitches) and installed some mechanicaly actuated micro-switches
instead. In my 235, I've occasionally had the magnetic rod (the one that is
supposed to trip the switches) miss actuating said switches and coast right
on by. The most likely result on 235's (in the reflex direction) is jamming
of the flap drive in the reflex position. It jams tightly enough that it
won't recover - the breaker just pops and the flaps won't move. You've got
to get at the flap drive and disconnect the push rod and manually un-jam the
mechanism. Interestingly, I found out what the landing characteristics of my
235 are with the flaps stuck in reflex (not all that different - but I did
add about 10-15 knots just in case)!

I found that I could get this to happen fairly regularly by "milking" the
flaps into reflex (all but one incident happened during run-up / preflight,
fortunately). Apparently, the motor coasts just enough to go past where it
would normally be stopped by the switches, then just keeps on truckin' until
everything jams up and the breaker pops.

I've mentioned this before and I intend to replace my magnetic switches at
the next annual (or condition inspection, or what have you) next spring.
Mechanically actuated switches, installed so that they stay actuated once
the flaps reach the desired limit, will remove this aggravating feature.

Dan Schaefer


LML website:   http://members.olsusa.com/mkaye/maillist.html
LML Builders' Bookstore:   http://www.buildersbooks.com/lancair
Please remember that purchases from the Builders' Bookstore
assist with the management of the LML.

Please send your photos and drawings to marvkaye@olsusa.com.

Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster