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You are describing classic symptoms of vapor lock.
I wish you had a Hodges vapor tester and a pressure gage on pump inlet. You'd
discover they had the same reading. You were probably within 1 degree F of total
loss of power.
Vapor tester:
The neat thing is, you can actually measure how
much vapor safety margin you have. Without flying. Just get that Hodges tester,
measure vapor psi of your fuel. Let the fuel sit in the sun, measure temp,
repeat test. You will be able to see how temperature affects vapor point. Do
this for 100LL and car fuel, see the difference.
Compare Hodges number to your inlet pressure,
that's your safety margin.
So as you can see vapor lock is extremely simple
concept.....except there are lot's of things that change that Hodges value. All
of these things make it worse.
Ethanol
inlet filter type
plumbing flow restriction between tank and
pump.
oat
plane sitting on tarmac
low fuel level
High power setting and low power
setting
High altitude
fuel return location
hot fuel pump
lot to lot variation in fuel
fuel head pressure
Like all failures, you can fly for years with a
marginal fuel design. Suddenly, you are in unusual circumstances and don't
realize it. Typically, high elevation airport, hot day, plane sitting on tarmac
for a while.
You really can design a fuel sys that is way way
lower risk. Not just vapor lock lower risk, but all other factors too. Don't
copy a marginal fuel design. Copy one that has a huge safety margin. Don't
guess, measure it.
This one has largest safety margin I know
of:
BTW, the pressure regulator is a very simple
device. Fuel pushes on one side of valve, spring pushes on other side. Highly
unlikely for it to fail as described.
-al wick
----- Original Message -----
Sent: Thursday, August 18, 2011 3:25
AM
Subject: [FlyRotary] Re: Sam Hodges NTSB
write up
My probllem with fuel starvation. The fuel
pressure regulator is another component to look at.
A few weeks ago, while in flight, the engine
started to loose power. A quick scan showed the fuel pressure going
down, it went down to about 7 psi. I switched fuel pump B on. the
pressure came up to about 27 psi. with the two pumps on and I landed, I
was in the circuit at the time. While taxiing back to the hangar I
turned pump A off and the pressure went down, then I turned pump B off and the
pressure went down. The next day I went back to test the system, I
started the engine on one fuel pump, as usual, the fuel pressure was
about 38 psi. as it has been every time before. Did a few runs on the
runway to warm things up, (no takeoff) everything was ok, fuel pressure was
normal all the time, on one fuel pump of the other. Returned to
the hangar, ordered a new fuel pressure regulator (a new MAZDA regulator) and
installed it a few days later, went flying. The problem never
returned.
----- Original Message -----
Sent: Tuesday, August 16, 2011 12:18
AM
Subject: [FlyRotary] Re: Sam Hodges
NTSB write up
But was it flown as the photos show without shielding for the
injectors ??.............
Kelly Troyer
"DYKE DELTA JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold
"TURBONETICS"_TO4E50 Turbo
From: "bktrub@aol.com" <bktrub@aol.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Monday, August 15, 2011 9:03
PM
Subject: [FlyRotary] Re:
Sam Hodges NTSB write
up
Exactly my thoughts. Really a
nece installation- but needs heat
sheilding above the exhaust
manifold.
Brian Trubee
-----Original
Message----- From: kenpowell@comcast.net To: Rotary motors in aircraft
<flyrotary@lancaironline.net> Sent: Mon, Aug 15, 2011 6:59
pm Subject: [FlyRotary] Re: Sam Hodges NTSB write up
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