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My idea is that the most efficient use of a dual (redundant)
EWP set-up is that they should be run in PARALLEL with two simple non
return valves. Yep, sure it's a bit more complicated to engineer,
but I believe it is worth the extra effort.
I can't
argue this as well, but like many things in an aircraft, it is a compromise
between efficiency and simplicity, due to weight and reliability concerns. I'd
love to have them in parallel as I have with my entire fuel system, but the fuel
system was easy as the pumps have a built in check valve. I did build a flapper
style valve, but really don't trust it. As I've had to make a set of nipples for
it, I'm now considering a design that would combine a check valve right at the
outlet of the pump. Leon, you should mention to Richard Davies the desirability
of a non-restricting check valve built in to the pump.
I will try to get some real flight data with the series
installation today but right now the weather is terrible. It's supposed to clear
for awhile tomorrow. I will still work towards a parallel installation, if only
for performance comparison testing.
Attached
is a pic of the valve I made. Keep in mind that I made it without the aid of
machine tools. For those of you with a milling machine you could make this allot
nicer.
S. Todd Bartrim Turbo 13B RV-9Endurance C-FSTB http://www3.telus.net/haywire/RV-9/C-FSTB.htm
"Whatever you vividly imagine, Ardently desire, Sincerely believe in,
Enthusiastically act upon, Must inevitably come to pass".
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