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There are systems that work just like that. I believe they are called
ADIABATIC, but the way I spell you would think English is my second
language.
The problem I see is complexity and weight.
An electronic absolute pressure sensor is light and simple and lasts
forever.
There one, or more, on every car.
So then all we need is a "pop off" solenoid, and a way for the MAP to tell
it to open.
Now if you only had a redundant electronic "brain" the we could use to open
the "pop off" solenoid....
One we could wire the MAP(<-HINT) to...
What is that saying of pooh bear? "think... think... think..."
----- Original Message ----- From: "Marvin Kaye" <marv@lancaironline.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, June 10, 2004 10:07 PM
Subject: [FlyRotary] Re: Pop off
Hey guys,
We've been talking about these pop-off valves as safety devices for some
time,
but the problem always seems to be that the available crop of these things
will only work at sea level. This is an obvious shortcoming for airplane
applications, as the MAP will always be decreasing with altitude.
I've been kicking around some ideas for awhile and came up with a little
drawing of one of these things that, I think, addresses the problem. See
the
attached picture.
My thinking is that if you create a chamber where you carry around your
sea
level altitude with you, close it off with a piston, the exposed side of
which
is open to the atmosphere, then as your altitude increases the piston
should
move down an amount equal to the change in atmospheric pressure. It then
applies the required additional force to our spring and keeps a steady
20psi
of force on the valve at the bottom. (This would be the equivalent of 40"
hg
MAP, but you could make it be whatever you want by changing the spring
rate.)
As you can see, the exposed sides of both the movable piston and the
valve
are seeing atmospheric pressure... in this example drawing the piston and
valve's areas are both one square inch, just to keep things simple.
Now, for the $64,000 question... what's wrong with this? If it won't
work,
why not? What do we change to make it work? This can't be that hard.
Suggestions????........
<Marv>
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