REFLECTOR: Aileron Tube Seal

[Alex Balic]

Chuck- do you mean "elevator" torque tube? that sounds like a good solution-
others have used the soft side of Velcro to seal this gap as well, but I
think that your method would have less drag.

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
Behalf Of Chuck Jensen
Sent: Wednesday, February 16, 2005 6:36 PM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: Aileron Tube Seal


If my Velo is typical, air intrusion around the aileron torque tubes
penetrations thru the side of the hull is a primary location of cold air
infiltration.  This is apparently a high pressure area.  Ronnie Brown had a
fix of building a kind of air-dam ahead to reduce the air pressure in that
area.  Better, but not quite what I needed for flying in <32F weather.

After multiple attempts at fixing this problem, I've come up with a
near-perfect solution.  I took some 1 1/4" diameter, very thin walled clear
rigid plastic tubing (from Aquarium shop) and cut off a chuck 3" long.  I
then used a scissor split the side of this short tube, so I'm left with a
split tube much like the foam pipe insulation you can put around your water
pipes.

I then snapped this over the 1" aileron torque tube.  You will note, the
extra 1/4" overlap come into play--later.  The plastic sleeve is slid
outboard so it is situated in the circular notch where the torque tube goes
thru the side wall. You will be able to see one end of the sleeve in the
cockpit (standing on your head) and the other end outside and under the
canard.

The plastic tube now acts as a sleeve around the torque such that when you
move the elevator up/down, the torque tube rotates inside the plastic sleeve
which is stationary against the hull.  Then, using silastic or other good
caulk/adhesive, fill in all the gaps/clearances between the hull and the
plastic sleeve.  You now have a perfect fit with zero in leakage and the
torque tube moves without resistance.  If you remove the canard, just pull
away the caulk and replace when the canard is reinstalled.

If you were too fine of a craftsman when you were forming your notch in the
side wall for the torque tube, there may not be enough clearance between the
hull and the torque tube for the plastic sleeve to slide past, so you may
have to open the hole up a little bit to let the plastic tube slide in
between the torque tube and the hull.  Now, you'll notice that the oversized
plastic tube overlaps on itself on the smaller 1" torque tube so when you
caulk it up, the overlap ensures to caulk can not contact the tube.  Total
cost:  About $10 for the rigid plastic tube and a little caulk.

Add heated seat pads, and its almost tolerable during a trip thru Iowa in
January.

Chuck
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