Ferg Kyle has sent an idea for positioning the fuel selector handle on top of the tunnel, remotely from the valve, which is in the base of the tunnel. It uses commonly available components - extension accessories for quarter inch drive sockets.
The first picture is a general arrangement sketch, followed by two pictures of the mechanical details. The rest of the text is Ferg's.
I hesitate to put more into the mail than necessary, (but it never stopped me before!) so here is my solution to placing the selector lever where the valve ain't. That is, an articulated shaft betwixt valve and lever. It comes in two parts because I'm not yet a master of the program which produced it.
There is a long shaft extension, and a short universal joint and lever shaft. Part one is the former, part two the latter.........
It's but a suggestion for further refinement, but mine is already in......... (also not PFA-approved). The idea came from my NA Yale at the museum. In 1938, they used Snap-On socket extenders in the manual flap crank mechanism!
Herewith the second part. I neglected to mention in part one, that these extenders (common items) may come in several qualities. I always choose the top, because it contains the strongest and most resistant metals and finishes - and we don't want to keep inspecting and replacing, especially in the trafficjam sections of the cockpit..........
There is one other inportant observation:- the extenders are square socket and have a small spring-ball retainer built in, to 'click' into place when assembled. These wee @#$%^'s are made out of Kryptonite or a canny copy of same. It pays (in drill bits) to avoid these when drilling for rollpins to ensure permanent capture. There is just room for a 3/32inch rollpin hole in the 1/4inch extenders I found.
The other limit worthy of mention might be obvious. Theoretically, one could devise a 90degree 'crank' in the Universal Joint, but I wouldn't want to. Useful as these joints are, I think a max of about 30deg crank is not unreasonable. Mine is quite smooth and the detent selection still quite discernable at about 30deg.
[In response to some questions] "Presumably you are not actually operating it at a deflection of 30 degrees,are you ? "
Actually, I just measured about 50 degrees! (I thought it was a lot less). The operation still seems smooth however, as I can still feel a definite detent in the lever selection - and this seems more a function of detent wear in the valve than any other. I'll try a sketch at the end of this email [the GA sketch, below].
"I imagine you have the lever on top of the tunnel, which slopes down in the aftwards direction and the valve somewhere down near the base of the tunnel, out of the way of the rudder cables ?"
Yes, I drilled a 1/2" hole in the tunnel roof about 16" ahead of the backrest wall, epoxied a roughened bronze 3/8"ID/1/2"OD bearing, with a SS 'fender' (wide OD) washer around it below, then 2 BiD to hold it in place and inserted the socket extender bar which was 3/8" OD. Where it extends above the bearing ferrule, I have machined it down to the 5/16" OD of the valve shaft for the selector lever. This in turn is drilled to accept a 1/8" setscrew to lock it to the shaft (there is also a 'flat' on the shaft, per the original valve shaft).
I have exercised the selector lever a lot of times but can detect no loss of 'feel' for the detents, nor for looseness or wear so far (the shaft of the extender should be much more resistant than is the brass shaft of the valve.
As to the valve itself, it sits on a Bid-covered plywood base made of three plies of 1.5mm aviation plywood epoxied together, which is 3" wide and spans the tunnel near the bottom skin. This base is in turn bolted to the tunnel sides by port/starboard alum angle, 3/4x3/4x1/8 and four -3 machine screws, two in the base, two in the tunnel sides each.
Cheers, Ferg A064 (VE3LVO@rac.ca )
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Problems with or comments on these pages please to John Cliff (john@crixbinfield.freeserve.co.uk) Vn 1.00 08/01/02