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Bertie the Bunyip[_2_] June 4th 08 06:33 AM

Ram air
 
"Ken S. Tucker" wrote in
:

On Jun 2, 10:13 am, Tina wrote:
On Jun 2, 12:01 pm, "Ken S. Tucker" wrote:

On Jun 1, 4:39 pm, Tina wrote:


The induction port for the ram air on the m20J bypasses the air
filter as well, so we typically observe about a half inch
improvement in MP. That's in line with some of the other numbers
offered here.


I guess there's no free lunch. There is no way we want to have an
IO540 pull the airplane along, nor do we want the fuss with turbo
charging. The payback for our typical for real flight mission is
just not there. My thought was and is that if it was something
pretty obvious someone would have done it on a homebuilt.
Actually, knowing some of those guys, it does not have to be
obvious at all, they are really creative designers.


Tina, I think this analysis you posted is good,
" It's only a 360 cubic inch engine turning at 2300 RPM or so.
Isn't that a demand of, let's see, at 23 inches mp at sea level
that's 23/30 * 2300/2 * 360 / 12^3 or 180 cubic feet a minute? "


I see Tango 2 Denny has some interesting ideas.
Ken


Well, I think it's a dead issue for us. What is fun to think about
is, let's see, about 200 cubic feet a minute, that's 40 cubic feet of
oxygen a minute, or about 3 pounds. For 50% more O2, 1.5 pounds a
minute, or say 20 pounds to get to a pleasantly high altitude. Maybe
that translates in to dewer weighing a total of 50 pounds with liquid
O2? But it would make 15 inches of MP look like 22 or so as far as
the engine is concerned. I better get back to my day job.


Without crackin' the books and pounding the abacus,
you look like +/- 20% using BoE (Back of Envelope)
calculation, which means you get either 80% or 120%
on your physics exam, you choose.

Resolved: psychologists should not be permitted to minor in the
physical sciences. All in favor?


OR pilots should not be permitted to engage in
psychology in this group, now what's the chances
of that happening...is "nil" close :-).
Ken
PS: What's the rationale of the 12,000' cruise?
You know about the "bends" don't you, if not
just read Berties post!


I double everyone up.


Bertie


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