Posted Saturday, 1/10/2009
Retractable Landing Gear - Plumbing Details
To make all this stuff work, the retracts require a bit of support in the form of fittings, lines, air
storage, etc. The photos below show what's involved in getting all that stuff to work. These particular retracts are pretty
simple, requiring only air pressure to retract. There are other systems on the market that require air pressure to retract
as well as to extend for landing.
This is the air storage tank. It is pressurized to about 100
psi and supplies enough air to operate the retracts for about 12 cycles.
This is the plywood mount I cut out from scrap for the tank pressure gauge and the one-way
fill valve. The gauge was purchased from Altecare RC. It costs about $20. The fill valve came with the retract kit. The gauge did not.
Rear view of the valve-gauge mounting. You can get the valve with a tee fitting or single
straight connector.
The assembly installed in the plane. This was the most logical place to put it and was
a recommendation by a fellow builder.
This is the actuator valve. It is located in the aft section of the plane and is operated
by a dedicated servo. The Spektrum DX7 radio has a specific channel for gear use. Air lines a are easily routed from front to back with a coat hanger. Just slide the
end of the airline on the end of the coat hanger and pull through.
Looking down on some of the plumbing lines installed. Tee fittings are the common method
of bringing 3 lines together, effectively connecting them in parallel. I don't know if the yellow wire ties held or hindered
the installation. I didn't install them on all connections. The tee fittings and airlines could be better quality and
I may eventually replace them both. Air line is cheap, but those tees are $7 each and I have 3 of them in the plane.
Another shot of the installation with lines going back to the main gear retracts.
