Ram air

The Mooney 201 has a ram air port, a half a foot under the prop
spinner. The POH tells us it can be opened at altitude for a very
modest increase in MP and we find maybe a half inch increase in
pressure. The idea of the thing is, if the port is looking right at
the air being thrust toward it by the prop (it can't be more than 6
inches or so behind it) as well as the air impact from the airplane's
motion the air being 'rammed' into it should effectively lower the
altitude the engine thinks it's at. Well, a half inch of Hg is about
500 feet or so. The question is, though, wouldn't you think there
would be a way to capture a great deal more of the ram air effect and
really boost the engine performance? Who wouldn't like to fly at 24
square at 12000 feet without a turbo charger?

What makes me wonder about it is, even at 60 mph holding your hand out
of the window of a car subjects it to a significant backward pressure,
so the energy must be there.

On Jun 1, 8:35*pm, Tina wrote:
The Mooney 201 has a ram air port, a half a foot under the prop
spinner. The POH tells us it can be opened at altitude for a very
modest increase in MP and we find maybe a half inch increase in
pressure. The idea of the thing is, if the port is looking right at
the air being thrust toward it by the prop (it can't be more than 6
inches or so behind it) *as well as the air impact from the airplane's
motion the air being 'rammed' into it should effectively lower the
altitude the engine thinks it's at. Well, a half inch of Hg is about
500 feet or so. The question is, though, wouldn't you think there
would be a way to capture a great deal more of the ram air effect and
really boost the engine performance? Who wouldn't like to fly at 24
square at 12000 feet without a turbo charger?

What makes me wonder about it is, even at 60 mph holding your hand out
of the window of a car subjects it to a significant backward pressure,
so the energy must be there.

An interesting question. I will have a stab at it but its just an
intuitive guess. Thrust is created by the prop pushing the air
backwards. If you are trying to capture that air into the engine,
there must be some resistance and therefore if you restrict the
ability of the air to be pushed away the thrust would be reduced. So
it must be a balance between not reducing the thrust and getting more
air into the engine to generate more power. I am also guessing that
for the ram air to be of much use it would probably be bypassing the
airfilter, which is potentially not good for the engine. although at
high altitude it is probably Ok, except perhaps for ice formation if
there was a lot of moisture in the air?

Isnt a Mooney fast enough for you Tina?
Terry

Tina wrote in news:f9933f5e-0c1d-464b-a1d8-
:

The Mooney 201 has a ram air port, a half a foot under the prop
spinner. The POH tells us it can be opened at altitude for a very
modest increase in MP and we find maybe a half inch increase in
pressure. The idea of the thing is, if the port is looking right at
the air being thrust toward it by the prop (it can't be more than 6
inches or so behind it) as well as the air impact from the airplane's
motion the air being 'rammed' into it should effectively lower the
altitude the engine thinks it's at. Well, a half inch of Hg is about
500 feet or so. The question is, though, wouldn't you think there
would be a way to capture a great deal more of the ram air effect and
really boost the engine performance? Who wouldn't like to fly at 24
square at 12000 feet without a turbo charger?

What makes me wonder about it is, even at 60 mph holding your hand out
of the window of a car subjects it to a significant backward pressure,
so the energy must be there.



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

The m20J is pretty slippery already and when it was introduced in the
70s was a big step up in efficiency in a production airplane.
Homebuilts do do an even better job of cleaning up aerodynamically.

The little seals on the flaps and so on were lipstick, the real gain
over the Mooney Executive had to do with the 201 getting a more
aerodynamic windscreen and engine cowling.

We have no serious complaints at all about the airplane (well, in a
rainstorm getting in without getting the seat wet is difficult,
checking the fuel is hard on pantyhose sometimes) but finding a couple
more inches of manifold pressure would be very handy when trying to
get to 12000 feet quickly. Once there, we can sip 8 gallons an hour
and move along pretty well.

I think using ram air would not increase aerodynamic drag, B. Instead
of having the air moving at the airplane's airspeed plus prop induced
speed impacting the cowling, it could in fact be going into a hole.
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 better leave that to the engineers.




On Jun 1, 7:57 am, Bertie the Bunyip wrote:
Tina wrote in news:f9933f5e-0c1d-464b-a1d8-
:



The Mooney 201 has a ram air port, a half a foot under the prop
spinner. The POH tells us it can be opened at altitude for a very
modest increase in MP and we find maybe a half inch increase in
pressure. The idea of the thing is, if the port is looking right at
the air being thrust toward it by the prop (it can't be more than 6
inches or so behind it) as well as the air impact from the airplane's
motion the air being 'rammed' into it should effectively lower the
altitude the engine thinks it's at. Well, a half inch of Hg is about
500 feet or so. The question is, though, wouldn't you think there
would be a way to capture a great deal more of the ram air effect and
really boost the engine performance? Who wouldn't like to fly at 24
square at 12000 feet without a turbo charger?

What makes me wonder about it is, even at 60 mph holding your hand out
of the window of a car subjects it to a significant backward pressure,
so the energy must be there.

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

"Tina" wrote in message ...
The m20J is pretty slippery already and when it was introduced in the
70s was a big step up in efficiency in a production airplane.
Homebuilts do do an even better job of cleaning up aerodynamically.

The little seals on the flaps and so on were lipstick, the real gain
over the Mooney Executive had to do with the 201 getting a more
aerodynamic windscreen and engine cowling.

We have no serious complaints at all about the airplane (well, in a
rainstorm getting in without getting the seat wet is difficult,
checking the fuel is hard on pantyhose sometimes) but finding a couple
more inches of manifold pressure would be very handy when trying to
get to 12000 feet quickly. Once there, we can sip 8 gallons an hour
and move along pretty well.

I think using ram air would not increase aerodynamic drag, B. Instead
of having the air moving at the airplane's airspeed plus prop induced
speed impacting the cowling, it could in fact be going into a hole.
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 better leave that to the engineers.




Yes, you are sucking it up as you are trying to push it in, the air that is, and the free airstream is not a very good
'pump'. A turbo with its sealed compressor is much better because once the air is captured it really has a hard time
flowing out backwards.

Tina wrote in news:7b4d9502-9229-4724-9b25-
:

The m20J is pretty slippery already and when it was introduced in the
70s was a big step up in efficiency in a production airplane.
Homebuilts do do an even better job of cleaning up aerodynamically.

Yeah, I've flown a good few 201s and 231s. Mostly the latter. They do
exactly as advertised!

The little seals on the flaps and so on were lipstick, the real gain
over the Mooney Executive had to do with the 201 getting a more
aerodynamic windscreen and engine cowling.

Well, I was talking about aftermarket stuff. There's lots for Mooneys,
but maybe they're all for the early airplanes. Havign said that, on a
relatively small engined but clean airplane, a small improvement in drag
reduction pays large dividends in efficiency. Not only that, they;re
cumulative, so if you make an improvement in one area, it's benefits are
compounded by one in another.


I think using ram air would not increase aerodynamic drag, B. Instead
of having the air moving at the airplane's airspeed plus prop induced
speed impacting the cowling, it could in fact be going into a hole.
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?

Well, it's more than likely that Mooney saw a little opportunity to add
that feature when they were analising the flow around the inlet area and
saw a bit of wasted air they could put to good use. they don't like
waste, those guys.
Al's designs were almost all masterpieces. My own favorite is the
Alexander Eaglerock which was his first. A startlingly efficient design
for it's day and my favorite machine of the period. The Bullet was just
unreal, though. Someone's got one flying now. What i wouldn't give to
fly it! Of course, the final design was far removed from Al's original
anyway, so I guess it can't really join the long list of his beauties...

Bertie

On Jun 1, 6:21*am, Tina wrote:
The m20J is pretty slippery already and when it was introduced in the
70s was a big step up in efficiency in a production airplane.
Homebuilts do do an even better job of cleaning up aerodynamically.

The little seals on the flaps and so on were lipstick, the real gain
over the Mooney Executive had to do with the 201 getting a more
aerodynamic windscreen and engine cowling.

We have no serious complaints at all about the airplane (well, in a
rainstorm getting in without getting the seat wet is difficult,
checking the fuel is hard on pantyhose sometimes) but finding a couple
more inches of manifold pressure would be very handy when trying to
get to 12000 feet quickly. Once there, we can sip 8 gallons an hour
and move along pretty well.

You don't get a couple inches on the 201. You will hardly notice the
difference and most 201 owners remove the cabling since it adds
complexity to annual (having to drop the cowl and re-rig the cable
each time). In the pre-201's it adds 3/4 of an inch.
The 201 easily gets to 12,000 feet. I live at the foot of the Sierras
and sometimes cross at 16,000 without turbo. If you don't have it
already most of us consider an engine monitor to be minimum equipment
for take off. Add to that a fuel computer (I wouldn't own a plane
without one) and you can really manage your fuel.

-Robert, Mooney CFII

"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.

"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

"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?