From: N295P@aol.com
Message-ID: <a50ae9da.248f0f50@aol.com>
Date: Tue, 8 Jun 1999 20:29:04 EDT
Subject: Re: Flaps 
To: brakes1@bentonrea.com, lancair.list@olsusa.com
Mime-Version: 1.0

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FLAPS: 

Addendum to my letter yesterday. I was incorrect on the description of the 
IV's flap cylinder stops, it has been a while since I rigged them. Here's how 
I did mine.

The flap actuator cylinder (HC-09) is a reduced travel actuator, designed to 
be the UP and DOWN stop at the end of it's range of travel, each way. The 
center flap bellcrank (make sure you have the new reinforced one), is set to 
travel an equal amount on either side of centerline, as per page 21-15. At 
the UP position, I added a 1/2" or so, rigging wood block to stop the 
bellcrank's travel, roughly keeping the top (long) arm of the bellcrank 
parallel to the front member of the MG box. The block touches the cylindrical 
end of the long arm of the bellcrank at full UP and is instant glued to the 
backside of the front MG box member. The flap pushrods going out to the wings 
can then be final adjusted with no fear of going further. Have a helper or 
use duct tape to place the flaps in their full UP position, firmly against 
the forward ends of the flap tracks, while you adjust the pushrods to the 
center bellcrank.

The actuator can then be installed, set at it's full extension, with the rod 
end about 3/4 screwed onto the shaft of the actuator and installed to the 
bellcrank. The actuator at full extension then defines it's rear bracket 
attach point. If all is well, the UP stop is the actuator at full extension, 
with the DOWN stop the actuator fully retracted. You should have 1/8" left of 
travel at the rear end of the flap tracks on the wings, in full DOWN, thereby 
insuring that nothing is loaded in compression. You cycle the flaps a few 
times, knock off the wood block; then recheck that at full UP, the wing 
pushrod length is snug to the bellcrank, not in a forced position. Tighten 
all the nuts, checknuts. A bit of grease on the bearings and years of good 
service will follow. Do make sure that the pushrods coming in from the wings 
have clearance for their full range of motion, especially where they 
penetrate the fuselage. I had to enlarge the opening slightly on one side.

Finally, there is a service bulletin requiring the rear actuator attach 
bracket to be inspected for cracks. Since the hydraulic shaft is retracted in 
the DOWN position, I usually leave my flaps down in the hangar to keep it 
retracted in fluid and not corroding. Note that this is the also the case 
with the gear down: shafts are internal and clean.

Robert Forest, N295P.

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