From: N295P@aol.com
Message-ID: <ebe4ec4d.248bfea3@aol.com>
Date: Sun, 6 Jun 1999 12:41:07 EDT
Subject: Actuator stops
To: lancair.list@olsusa.com
Mime-Version: 1.0

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RE: Actuator travel.

This is from a IV builder who knows not about the setup in the 235-320-360 
planes. 

In the IV, under no circumstances should your actuator cylinders reach the 
end of their travel in the bore of the cylinder. The UP stop for all 3 gears 
are the HDPE blocks in the nosegear wheelwell and on the MG box. The DOWN 
stops are the NG scissor making hard slight overcenter contact and for the 
mains, the 1/3 round plastic stops on the front of the MG box. In addition, 
for the MG, there are drop pins within the massive actuators that lock the 
mains in the down position. So, yes the main pistons do bottom out at the 
lock point, but you adjust the travel of the rack so that the hard point is 
the HDPE pad and not the downlock. There is a pair of beefed-up NG scissor 
links available from Lancair, I recommended to get 'em. You should also 
replace the backup NG emergency, precharged cylinder every couple of years, 
cheap insurance. Don't forget to test your emergency extension handpump every 
now and then, and to cycle the gear on stands yearly. Emergency hand pump is 
not a great design and can easily leak a bit.

DOWN and LOCKED indicator switches are at the scissor, for the NG; on the 
front lip of the MG box for the mains. I also have a second switch on the 
mains, at the same place, for a warning to get the gear down if the throttle 
is closed, with another switch in the door pins if the throttle is opened and 
the door not locked, all connected to an annunciator light.

As for the flap actuator, there is a retrofit, beefed up bellcrank that you 
get from Lancair for $35, or so, as a cost-share part improvement. The flap 
UP stop is the actuator and bellcrank connect point abutting the front of the 
MG box. The DOWN stop is the flaps traveling to the front end of the tracks. 
Lots of adjustments available to allow rigging. There is also a check item 
for cracks in the rear flap cylinder attach bracket for cracks at the 
manufactured bend point, to be done yearly. 

Moral of the story: let there be no other stop than the intended hardpoint.

Robert Forest, N295P
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