Ram air

On Mon, 2 Jun 2008 13:38:57 -0700 (PDT), Billy Crabs
wrote:

On Jun 2, 9:28*am, Bertie the Bunyip wrote:
"Maxwell" luv2^fly99@cox.^net wrote in news:jTR0k.192$js1.25
@newsfe24.lga:









"Bertie the Bunyip" wrote in message
.. .
"Maxwell" luv2^fly99@cox.^net wrote in
:

"Bertie the Bunyip" wrote in message
...
Didn't know any production aircraft had that. Well, to some extent
almost every lightplane does . that's why the carb air intake faces
forwards in most of them.Everything is a balancing act with an
airplane. More air = more drag. You could try putting a couple of
woks with tubes out the back to boost your MP, but you're going to
pay for it. !Moooney must have spotted an area of the cowl that
would
not penalise you in this way and decided to utilise it. Really
clever
homebuilders do a lot of this kind of stuff as well as, and
probably
more more importantly, dealing with cooling drag.
Have you put the other speed mods on your airplane? I think there's
nearly ten knots available in seals and various other tidy it up
fairings.

Bertie

Dumb ass.

Its because the size of the scoop increases volume (not pressure),
and
you already have too much.

Nope.

Bertie

How would you know, dumb ass?

I know everything, obviously.

Bertie- Hide quoted text -

- Show quoted text -

Ram air is only as useful the allowing air to get to your carburater
faster but is not necessarily used. When your piston is on its intake
stroke(vaccum) your combustion chamber can only draw in enough air
that is in conjuction to the chambers volume and all other air that is
present after the compression stroke is exported to engines smog
devices and is recirculated only AFTER being filtered. All engines
come off the assembly lines, be it an airplane motor or a vehicle
motor, to draw the amount of air that it needs to run at opptimum
performance. Ram Air is a myth and don't try to throw "turbo" into
the conversation because turbo is recircualted exhaust and still has
unburnt fuel in the fumes.

**************************************
Billy

Don't know where you got ur data. My turbo had the turbine wheel
turned by the exhaust. The turbine wheel was connected to the
compressor wheel which took ambient air and compressed it and ran it
thru the carb and into the engine. Always has and always will.

You may be talking about an auto engine and the exhaust gas
recirculation system to help meet EPA standards.?

Big John

On Tue, 03 Jun 2008 13:17:17 -0400, mixed nuts
wrote:

Stealth Pilot wrote:
On Mon, 02 Jun 2008 19:51:47 -0400, dave hillstrom
wrote:


On Mon, 2 Jun 2008 14:12:26 -0700 (PDT), Tony
wrote:


Ram air is only as useful the allowing air to get to your carburater
faster but is not necessarily used. When your piston is on its intake
stroke(vaccum) your combustion chamber can only draw in enough air
that is in conjuction to the chambers volume and all other air that is
present after the compression stroke is exported to engines smog
devices and is recirculated only AFTER being filtered. All engines
come off the assembly lines, be it an airplane motor or a vehicle
motor, to draw the amount of air that it needs to run at opptimum
performance. Ram Air is a myth and don't try to throw "turbo" into
the conversation because turbo is recircualted exhaust and still has
unburnt fuel in the fumes.

I think you are quite wrong. Ram air in fact gives us a half inch or
so more manifold pressure, and that increases the total weight of the
air-fuel mixture in the cylinder. Reduce your 'it doesn't matter
argument to an extreme to see how it fails.

As for turbos, the turbine is powered by the exhaust gasses coming

from the engine, the exhaust gas itself is not reintroduced into the

cylinders. The turbine itself could be powered by an electric motor,
for that matter. That was the model for my tongue in cheek comment
about using a shop vac to increase manifold pressure.

will you marry me?

dave the term is not foo and bar.
foo *is* a term from another war and another airforce
but the term you've so successfully stuffed up is fubar
fubar is a vietnam era acronym of F***ed up beyond all recognition.

your sig line is a snafu
(situation normal all F***ed up)

Yore 'rong. foo and bar are metasyntactic variables. They aren't
acronyms (they're metasyntactic variables).

Like being the John and Jane Doe of computer engineering - placeholders.

Fubar predates WWII.
************************************************

Can you quote?

WWII Vet

Big John

On Tue, 3 Jun 2008 09:18:10 -0700 (PDT), "Ken S. Tucker"
wrote:

On Jun 3, 7:54 am, wrote:
On Jun 2, 9:45 pm, Billy Crabs wrote:

let me try to explain myself better, the amount of air that is drawn
into an engine is in direct coralation to cylinder volume and the cam
shafts "lift and duration" A valve can only stay open as long as the
cam lobe holds the lifter up, therefore only allowing as much air/fuel
as was scientificly formulated for the cylinder.
for instance, lets say you have two guys who are going to breath in
deep, now even if you are blowing an air hose in their faces, they are
only going to be able to inhale as much as there lungs will hold. Now
lets say they are inhaling pot and when they blow out its put into a
"turbo", the turbine spins and sends the unused pot back to their
lungs, but it's still only as much as they hold in their
lungs(cylinder volume)

Air density in the cylinder is governed by its pressure and
temperature. MUCH more air can be forced into the cylinder if the
manifold pressure is boosted; this is the principle behind getting
more power out of a given number of cubic inches. You need to do some
studying on the matter. I have, and I teach this stuff in college.
Dan

I wonder if ram scoops were ever installed near the
prop tips. Probably too expensive for GA, but a WW2
A/C with tips spinning at what(?) 500-600 mph would
give a nice pressure boost.
I've read dual phase superchargers were used in recon
A/C to get the speed and altitude.
Ken


**************************************************
Ken

The P-51 had a two speed supercharger. It shifted auto from low blower
to high blower between 12K and 14K depending on the sensor.

In high blower you could get sea level manifold pressure to almost
25K.

Big John

On Mon, 2 Jun 2008 11:19:41 -0700 (PDT), "Ken S. Tucker"
wrote:

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!

************************************************** *

Ken

Have you ever talked to anyone who got the bends flying? I have
thousands of hours and never have.

I have gone to 43K+ and made supersonic dives to 10K +/- with no
problems.

I have cruised for hours at 30K cockpit pressure and no problems
during let down and landing.

Big John

On Mon, 2 Jun 2008 12:31:53 +0000 (UTC), Bertie the Bunyip
wrote:

"Ken S. Tucker" wrote in
:

On Jun 1, 7:59 pm, wrote:
On Jun 1, 8:06 pm, Gezellig wrote:



It happens that formulated :

In the 1970's Ford sold some cars with "Ram-Air Induction"
systems. A scoop mounted on the carb that stuck out above the
hood, to ram vast volumes of air into the carb and get way more
horsepower. That's what they wanted you to believe. At 60 mph the
pressure recovery would have been laughably tiny, but Ford's
profits were impressive.

Had a Trans Am, scoop was reversed, facing the windshield, had a
flap that opened when MP increased. They claimd that the reversed
position was at the low pressure point at the base of the
windshield hence enhancing the rammed air effect. I don't know, it
was cool, the scoop assembly was attached to the engine so that on
acceleration you could see the engine sitting down on its mounts as
the scopp popped open and lowere ever so slightly.

Locating the scoop at the low-pressure point wouldn't do much
for ram-air effect, would it? I think the real idea would have been
to make sure the driver heard that thing sucking loudly so it sounded
like a real powerhouse
I once converted a 14 foot outboard runabout to a 13 foot
inboard Cracker Box with a Chev 283 straight-shaft setup. The
exhausts were water-cooled and exited through the transom. Made so
much noise that I made two mufflers and quieted it right down. The
carb's flame arrestor stuck up far enough that I had a scoop on the
deck, facing away from the cockpit (which was at the back).
Everything else was covered. I dropped my Dad off on a gravel bar on
a lake once, so he could fish off it while I ran to the far end of
the lake to try the fishing there, three or four miles away. He told
me he knew when I was coming back; he could hear that Rochester
Quadrajet four-barrel open up and suck vast quantities of air; the
boat got one mile per gallon at full throttle with that huge carb.
But went real fast. I sold it years ago and I bet it don't go real
fast no more, with fuel prices the way they are now.
Dan

I confess to enjoying ancedotal stories.
As a monster nut brat I got some tin cans together
and built a pulse jet, complete with a flapping duct
input, and used a hair dryer for my air input source,
in my parents downstairs fireplace.
So I pour in some gas into the thing, lite it up,
turn on the hair dryer and holy poop, the duct starts
fluttering and flames are fluttering out the ass end!
It worked! It buzzed!

I probably used a pint of gasoline per minute of
operation, but that wasn't the point, it was actually
seeing the damn thing in operation.
Hands on is good stuff.


Please do build another one just like that and put it on youtube, then..


I've only ever seen one person die right in front of my eyes before.


Bertie
************************************************** *******

Bertie

I've seen two. Both stalled and spun in (

Big John

Big John wrote in
:

**************************************
Bertie

Death is not a pleasant occurrence or subject.


Well, at 95, in your own bed, not so bad.

First was a 51 that stalled in pattern and made about one full turn
before hitting water off end of R/W in Japan. Never saw the remains. I
was about 100 yards from impact.

Second was a P-80. Took of on a test flight at Willie Air Patch (First
Jet School) and stalled about 1000 feet (for some reason) and made
several turns before impact. Burned. I was one of the first on scene
and covered the torso . Arms and legs had burned off in fire (

This is not a good subject for RAP.

Yeh,

Fly safe and live long.


Do my best!


Bertie

I always wondered if they cut his microphone off so they couldn't hear him
freaking out as the ground loomed nearer and nearer and nearer and then
screaming in terror/pain as he started to skim the ground. Can you imagine
having to listen to that? It would be like, "Oh man... Oh MAN. HOLY
****!! GET ME THE **** OUT OF HERE GODDAMMIT!!!!! OH MY GOD
AAAAAAAAAAAAAAAAA" and then there would be utter silence and a long reddish
brown trail of goo down the runway.

We've all heard those stories, and there are many more equally
horrible. I think what the people who were on the Indy when it was
torpedoed toward the end of WW2 went through is at least as horrible,
and we know that happened, the shark feeding frenzy is well
documented.

Do we know for sure if that belly gunner -- gear up landing scene
really happened?

This is not an attempt to belittle any who have put themselves at risk
for the rest of us: the question I have is do we know with certainty
the gear up landing with a trapped belly gunner is reality based or is
it from a film?

On Jun 4, 5:03 pm, Tina wrote:

Do we know for sure if that belly gunner -- gear up landing scene
really happened?

This is not an attempt to belittle any who have put themselves at risk
for the rest of us: the question I have is do we know with certainty
the gear up landing with a trapped belly gunner is reality based or is
it from a film?

It happened more than once. The ball turret was operated by a
mechanism that would get shot out and so the gunner couldn't get the
ball back up into the fuselage to get out of it.

Dan

"gregvk" wrote in message
...

I didn't hear it from a film. I heard about it from some old guy who saw
one land that way. The craft's hydraulics got damaged and stopped
working,
which made it impossible to drop the landing gear or to rotate the ball
turret (it had to be properly positioned in order for the gunner to open
the little door and climb into the craft) so the gunner was stuck in there
and they had to belly land. I always thought the B-17 had a manual
override crank or something to rotate the ball turret by hand... But
maybe
they didn't all have those, or it was also damaged (or maybe I'm mistaken
about the existence of a manual override).


Hey Bertie, your forgot to change your name back!!!

:0)

"Maxwell" luv2^fly99@cox.^net wrote in
:


"gregvk" wrote in message
...

I didn't hear it from a film. I heard about it from some old guy who
saw one land that way. The craft's hydraulics got damaged and
stopped working,
which made it impossible to drop the landing gear or to rotate the
ball turret (it had to be properly positioned in order for the gunner
to open the little door and climb into the craft) so the gunner was
stuck in there and they had to belly land. I always thought the B-17
had a manual override crank or something to rotate the ball turret by
hand... But maybe
they didn't all have those, or it was also damaged (or maybe I'm
mistaken about the existence of a manual override).


Hey Bertie, your forgot to change your name back!!!

:0)






Did I? Do tell.


Bertie