Today's Message Index:
----------------------
1. 12:28 AM - Manifold Pressure (Scott Aldrich)
2. 08:38 AM - Re: Manifold Pressure (A. Dennis Savarese)
3. 08:50 AM - Re: Manifold Pressure (Ted Waltman)
4. 08:53 AM - Re: Manifold Pressure (Scott Aldrich)
5. 08:58 AM - Re: Manifold Pressure (A. Dennis Savarese)
6. 09:02 AM - Re: Manifold Pressure (A. Dennis Savarese)
7. 09:27 AM - Re: Manifold Pressure (Scott Aldrich)
8. 10:31 AM - Re: Manifold Pressure (A. Dennis Savarese)
Message 1
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| Subject: | Manifold Pressure |
Wonder what to expect (roughly) for a take off Manifold Pressure on a
standard day at a 5000' MSL airport with the standard M14P?
Thanks,
Scott
Message 2
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| Subject: | Re: Manifold Pressure |
Scott,
On a standard day at sea level, barometric pressure in inches is 29.92" which equals
760 mm. At 100% the supercharger boosts the pressure (at sea level) to
approximately 885 mm or 34.85", a factor of 1.165. At 5000' on a standard day
the barometric pressure should be about 24.9 inches, or 632 mm. Given the supercharger
boost factor, at 5000' with 100% rpm the manifold pressure should
come up to about 736 mm. I'm sure if my numbers are wrong someone will definitely
correct me. -)
Dennis
----- Original Message -----
From: Scott Aldrich
To: m14pengines-list@matronics.com
Sent: Monday, April 10, 2006 2:27 AM
Subject: M14PEngines-List: Manifold Pressure
Wonder what to expect (roughly) for a take off Manifold Pressure on a standard
day at a 5000' MSL airport with the standard M14P?
Thanks,
Scott
Message 3
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| Subject: | Manifold Pressure |
Dennis,
This whole debate started with a couple of us comparing MP on our M-14
engines. Yesterday, at roughly std temp--or maybe a few degrees warmer--I
saw 26.1" at takeoff at 4,965'. A standard engine on a Swift was showing
about 22" at takeoff (at 1,921 prop rpm or 2,919 engine rpm). We were both
at roughly 25" before engine start.
So, I'm not seeing the 736mm, or 28.97", you indicate below. Perhaps my
gauge is a bit off?
Ted
_____
From: owner-m14pengines-list-server@matronics.com
[mailto:owner-m14pengines-list-server@matronics.com] On Behalf Of A. Dennis
Savarese
Sent: Monday, April 10, 2006 9:38 AM
Subject: Re: M14PEngines-List: Manifold Pressure
Scott,
On a standard day at sea level, barometric pressure in inches is 29.92"
which equals 760 mm. At 100% the supercharger boosts the pressure (at sea
level) to approximately 885 mm or 34.85", a factor of 1.165. At 5000' on a
standard day the barometric pressure should be about 24.9 inches, or 632 mm.
Given the supercharger boost factor, at 5000' with 100% rpm the manifold
pressure should come up to about 736 mm. I'm sure if my numbers are wrong
someone will definitely correct me. -)
Dennis
----- Original Message -----
From: Scott <mailto:s-aldrich@comcast.net> Aldrich
Sent: Monday, April 10, 2006 2:27 AM
Subject: M14PEngines-List: Manifold Pressure
Wonder what to expect (roughly) for a take off Manifold Pressure on a
standard day at a 5000' MSL airport with the standard M14P?
Thanks,
Scott
Message 4
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| Subject: | Manifold Pressure |
That is about what I was thinking we should see roughly 29 inches. With no
real charts (that I know of or can understand) I am wondering when the
supercharger starts to loss it effectiveness in giving the approx. 5 inch.
Scott
_____
From: owner-m14pengines-list-server@matronics.com
[mailto:owner-m14pengines-list-server@matronics.com] On Behalf Of A. Dennis
Savarese
Sent: Monday, April 10, 2006 9:38 AM
Subject: Re: M14PEngines-List: Manifold Pressure
Scott,
On a standard day at sea level, barometric pressure in inches is 29.92"
which equals 760 mm. At 100% the supercharger boosts the pressure (at sea
level) to approximately 885 mm or 34.85", a factor of 1.165. At 5000' on a
standard day the barometric pressure should be about 24.9 inches, or 632 mm.
Given the supercharger boost factor, at 5000' with 100% rpm the manifold
pressure should come up to about 736 mm. I'm sure if my numbers are wrong
someone will definitely correct me. -)
Dennis
----- Original Message -----
From: Scott Aldrich <mailto:s-aldrich@comcast.net>
Sent: Monday, April 10, 2006 2:27 AM
Subject: M14PEngines-List: Manifold Pressure
Wonder what to expect (roughly) for a take off Manifold Pressure on a
standard day at a 5000' MSL airport with the standard M14P?
Thanks,
Scott
Message 5
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| Subject: | Re: Manifold Pressure |
Most likely the gauge is off, just like I know mine is. We're at 200' MSL here at our airport. So our MP gauges should read pretty close to 760 mm on a standard day. I can tell you this. Mine surely does not. It reads low by about 30-40 mm compared to the other 4 Yaks in our hangar. The numbers should be just about right I think. I used this site, http://www.digitaldutch.com/atmoscalc/, to get the standard atmospheric pressure at 5000'. The rest of the data came from the engine manual and basic calculations.
Dennis
----- Original Message -----
From: Ted Waltman
To: m14pengines-list@matronics.com
Sent: Monday, April 10, 2006 10:50 AM
Subject: RE: M14PEngines-List: Manifold Pressure
Dennis,
This whole debate started with a couple of us comparing MP on our M-14 engines.
Yesterday, at roughly std temp--or maybe a few degrees warmer--I saw 26.1"
at takeoff at 4,965'. A standard engine on a Swift was showing about 22" at
takeoff (at 1,921 prop rpm or 2,919 engine rpm). We were both at roughly 25"
before engine start.
So, I'm not seeing the 736mm, or 28.97", you indicate below. Perhaps my gauge
is a bit off?
Ted
From: owner-m14pengines-list-server@matronics.com [mailto:owner-m14pengines-list-server@matronics.com] On Behalf Of A. Dennis Savarese
Sent: Monday, April 10, 2006 9:38 AM
To: m14pengines-list@matronics.com
Subject: Re: M14PEngines-List: Manifold Pressure
Scott,
On a standard day at sea level, barometric pressure in inches is 29.92" which
equals 760 mm. At 100% the supercharger boosts the pressure (at sea level) to
approximately 885 mm or 34.85", a factor of 1.165. At 5000' on a standard
day the barometric pressure should be about 24.9 inches, or 632 mm. Given the
supercharger boost factor, at 5000' with 100% rpm the manifold pressure should
come up to about 736 mm. I'm sure if my numbers are wrong someone will definitely
correct me. -)
Dennis
----- Original Message -----
From: Scott Aldrich
To: m14pengines-list@matronics.com
Sent: Monday, April 10, 2006 2:27 AM
Subject: M14PEngines-List: Manifold Pressure
Wonder what to expect (roughly) for a take off Manifold Pressure on a standard
day at a 5000' MSL airport with the standard M14P?
Thanks,
Scott
Message 6
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| Subject: | Re: Manifold Pressure |
The super charger drop is basically linear, assuming 100% power. It never really
loses its "effectiveness". It will always boost above atmospheric pressure,
as long as it's turning. -) It just starts off higher (+5" approximately).
Dennis
----- Original Message -----
From: Scott Aldrich
To: m14pengines-list@matronics.com
Sent: Monday, April 10, 2006 10:53 AM
Subject: RE: M14PEngines-List: Manifold Pressure
That is about what I was thinking we should see roughly 29 inches. With no real
charts (that I know of or can understand) I am wondering when the supercharger
starts to loss it effectiveness in giving the approx. 5 inch.
Scott
From: owner-m14pengines-list-server@matronics.com [mailto:owner-m14pengines-list-server@matronics.com] On Behalf Of A. Dennis Savarese
Sent: Monday, April 10, 2006 9:38 AM
To: m14pengines-list@matronics.com
Subject: Re: M14PEngines-List: Manifold Pressure
Scott,
On a standard day at sea level, barometric pressure in inches is 29.92" which
equals 760 mm. At 100% the supercharger boosts the pressure (at sea level) to
approximately 885 mm or 34.85", a factor of 1.165. At 5000' on a standard
day the barometric pressure should be about 24.9 inches, or 632 mm. Given the
supercharger boost factor, at 5000' with 100% rpm the manifold pressure should
come up to about 736 mm. I'm sure if my numbers are wrong someone will definitely
correct me. -)
Dennis
----- Original Message -----
From: Scott Aldrich
To: m14pengines-list@matronics.com
Sent: Monday, April 10, 2006 2:27 AM
Subject: M14PEngines-List: Manifold Pressure
Wonder what to expect (roughly) for a take off Manifold Pressure on a standard
day at a 5000' MSL airport with the standard M14P?
Thanks,
Scott
Message 7
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| Subject: | Manifold Pressure |
That brings up the question (at least for me) if you had a small leak in the
MP line on a supercharged engine would that cause low indication due to
pressure loss? Whereas on none turbo or supercharged a leak may cause
higher indication due to less vacuum (because it is really vacuum and not
"pressure" on a standard engine, i.e. MP usually drops slightly when takeoff
power is applied). Too much thinking.
Scott
_____
From: owner-m14pengines-list-server@matronics.com
[mailto:owner-m14pengines-list-server@matronics.com] On Behalf Of A. Dennis
Savarese
Sent: Monday, April 10, 2006 9:58 AM
Subject: Re: M14PEngines-List: Manifold Pressure
Most likely the gauge is off, just like I know mine is. We're at 200' MSL
here at our airport. So our MP gauges should read pretty close to 760 mm on
a standard day. I can tell you this. Mine surely does not. It reads low
by about 30-40 mm compared to the other 4 Yaks in our hangar. The numbers
should be just about right I think. I used this site,
http://www.digitaldutch.com/atmoscalc/, to get the standard atmospheric
pressure at 5000'. The rest of the data came from the engine manual and
basic calculations.
Dennis
----- Original Message -----
From: Ted Waltman <mailto:tedwaltman@i1ci.com>
Sent: Monday, April 10, 2006 10:50 AM
Subject: RE: M14PEngines-List: Manifold Pressure
Dennis,
This whole debate started with a couple of us comparing MP on our M-14
engines. Yesterday, at roughly std temp--or maybe a few degrees warmer--I
saw 26.1" at takeoff at 4,965'. A standard engine on a Swift was showing
about 22" at takeoff (at 1,921 prop rpm or 2,919 engine rpm). We were both
at roughly 25" before engine start.
So, I'm not seeing the 736mm, or 28.97", you indicate below. Perhaps my
gauge is a bit off?
Ted
_____
From: owner-m14pengines-list-server@matronics.com
[mailto:owner-m14pengines-list-server@matronics.com] On Behalf Of A. Dennis
Savarese
Sent: Monday, April 10, 2006 9:38 AM
Subject: Re: M14PEngines-List: Manifold Pressure
Scott,
On a standard day at sea level, barometric pressure in inches is 29.92"
which equals 760 mm. At 100% the supercharger boosts the pressure (at sea
level) to approximately 885 mm or 34.85", a factor of 1.165. At 5000' on a
standard day the barometric pressure should be about 24.9 inches, or 632 mm.
Given the supercharger boost factor, at 5000' with 100% rpm the manifold
pressure should come up to about 736 mm. I'm sure if my numbers are wrong
someone will definitely correct me. -)
Dennis
----- Original Message -----
From: Scott Aldrich <mailto:s-aldrich@comcast.net>
Sent: Monday, April 10, 2006 2:27 AM
Subject: M14PEngines-List: Manifold Pressure
Wonder what to expect (roughly) for a take off Manifold Pressure on a
standard day at a 5000' MSL airport with the standard M14P?
Thanks,
Scott
Message 8
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| Subject: | Re: Manifold Pressure |
Yes, too much thinking for sure! -) Sounds about right to me.
Dennis
----- Original Message -----
From: Scott Aldrich
To: m14pengines-list@matronics.com
Sent: Monday, April 10, 2006 11:07 AM
Subject: RE: M14PEngines-List: Manifold Pressure
That brings up the question (at least for me) if you had a small leak in the
MP line on a supercharged engine would that cause low indication due to pressure
loss? Whereas on none turbo or supercharged a leak may cause higher indication
due to less vacuum (because it is really vacuum and not "pressure" on a standard
engine, i.e. MP usually drops slightly when takeoff power is applied).
Too much thinking.
Scott
From: owner-m14pengines-list-server@matronics.com [mailto:owner-m14pengines-list-server@matronics.com] On Behalf Of A. Dennis Savarese
Sent: Monday, April 10, 2006 9:58 AM
To: m14pengines-list@matronics.com
Subject: Re: M14PEngines-List: Manifold Pressure
Most likely the gauge is off, just like I know mine is. We're at 200' MSL here at our airport. So our MP gauges should read pretty close to 760 mm on a standard day. I can tell you this. Mine surely does not. It reads low by about 30-40 mm compared to the other 4 Yaks in our hangar. The numbers should be just about right I think. I used this site, http://www.digitaldutch.com/atmoscalc/, to get the standard atmospheric pressure at 5000'. The rest of the data came from the engine manual and basic calculations.
Dennis
----- Original Message -----
From: Ted Waltman
To: m14pengines-list@matronics.com
Sent: Monday, April 10, 2006 10:50 AM
Subject: RE: M14PEngines-List: Manifold Pressure
Dennis,
This whole debate started with a couple of us comparing MP on our M-14 engines.
Yesterday, at roughly std temp--or maybe a few degrees warmer--I saw 26.1"
at takeoff at 4,965'. A standard engine on a Swift was showing about 22" at
takeoff (at 1,921 prop rpm or 2,919 engine rpm). We were both at roughly 25"
before engine start.
So, I'm not seeing the 736mm, or 28.97", you indicate below. Perhaps my gauge
is a bit off?
Ted
From: owner-m14pengines-list-server@matronics.com [mailto:owner-m14pengines-list-server@matronics.com] On Behalf Of A. Dennis Savarese
Sent: Monday, April 10, 2006 9:38 AM
To: m14pengines-list@matronics.com
Subject: Re: M14PEngines-List: Manifold Pressure
Scott,
On a standard day at sea level, barometric pressure in inches is 29.92" which
equals 760 mm. At 100% the supercharger boosts the pressure (at sea level)
to approximately 885 mm or 34.85", a factor of 1.165. At 5000' on a standard
day the barometric pressure should be about 24.9 inches, or 632 mm. Given the
supercharger boost factor, at 5000' with 100% rpm the manifold pressure should
come up to about 736 mm. I'm sure if my numbers are wrong someone will definitely
correct me. -)
Dennis
----- Original Message -----
From: Scott Aldrich
To: m14pengines-list@matronics.com
Sent: Monday, April 10, 2006 2:27 AM
Subject: M14PEngines-List: Manifold Pressure
Wonder what to expect (roughly) for a take off Manifold Pressure on a standard
day at a 5000' MSL airport with the standard M14P?
Thanks,
Scott
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