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Subject: RE: [FlyRotary] Re: Fwd: Fuel systems
Date: Thu, 16 Oct 2003 10:28:59 -0400
Message-ID: <0B27ED95697C4D4CBC82D79E790FE567086F94@exchange.rfgonline.com>
Thread-Topic: [FlyRotary] Re: Fwd: Fuel systems
Thread-Index: AcOT34xW1BN2VfnITjab+Nts0e6i+wAEXqZg
From: "Robinson, Chad" <crobinson@rfgonline.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>

> The most common solution is probably a double throw valve. Bulent =
Alieve has
> a source of fairly inexpensive ones. I installed a solenoid which =
sends the
> return to the right tank when off, left when energized. I energize it =
with
> the left tank fuel pump switch. This way I have independant fuel =
supplies,
> pumps and filters. The solenoid weighs a couple of pounds. See details =
&
> pictures in http://kgarden.com/cozy/chap21b.htm search for hydraulics.

John, I really like your system, especially the isolation it provides =
and the ability to transfer fuel from one tank to another by controlling =
where the return goes. I have one question. When your solenoid fails =
it's just in one position or the other, so the return still has a place =
to go and you can just draw from that tank only to keep the plane =
balanced. But how do you know this has occurred? Have you had any =
thoughts regarding that, or is it just going to be a "plane's leaning, =
sir" seat of the pants feeling, and take a guess that the solenoid might =
have failed?

It's not a disastrous failure of course, but I've been trying to figure =
out a way to detect this without two more flow rate sensors on those =
returns and can't come up with much. I thought that perhaps a short =
section of clear tube, a small ball, and something for it to catch =
against could be used as a sight tube, if you don't mind running the =
return plumbing somewhere it can be seen - if the fuel is flowing, the =
ball (sized so fuel can flow around it easily, of course) will be =
fetched up against the screen/stop/etc.

But it's an additional complexity. Have you experimented with your valve =
at all, electronically? Might it possibly react to, say, a blockage, in =
some recognizable way, like excessive current consumption?

Regards,
Chad