What is the blue range indicating on this manifold pressure gauge?
$begingroup$
This is baffling me. Does anybody with experience with this type of indicator have any idea what the blue range of this gauge means?
It's mounted in a mock-up panel. I know nothing about where it originally came from, though it seems pretty clear that it's from a turbocharged piston twin.
flight-instruments piston-engine
edited 9 hours ago
David Richerby
9,92533578
asked 13 hours ago
PugzPugz
2,614827
$endgroup$
|
show 1 more comment
$begingroup$
This is baffling me. Does anybody with experience with this type of indicator have any idea what the blue range of this gauge means?
It's mounted in a mock-up panel. I know nothing about where it originally came from, though it seems pretty clear that it's from a turbocharged piston twin.
flight-instruments piston-engine
edited 9 hours ago
David Richerby
9,92533578
asked 13 hours ago
PugzPugz
2,614827
$endgroup$
$begingroup$
It would help to know what aircraft this gauge is in
$endgroup$
– DeepSpace
13 hours ago
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@DeepSpace I'm sorry I have no idea. It is a standalone gauge we have just sitting around, but it looks pretty clearly to be from a turbocharged piston twin.
$endgroup$
– Pugz
13 hours ago
$begingroup$
Related: Why don't airplane turbo piston engines have boost control?
$endgroup$
– ymb1
13 hours ago
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For being a "standalone gauge we have just sitting around", it seems to be pretty well screwed into a panel of some sort.
$endgroup$
– FreeMan
12 hours ago
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@FreeMan yes it is! Mock up panel.
$endgroup$
– Pugz
10 hours ago
|
show 1 more comment
$begingroup$
This is baffling me. Does anybody with experience with this type of indicator have any idea what the blue range of this gauge means?
It's mounted in a mock-up panel. I know nothing about where it originally came from, though it seems pretty clear that it's from a turbocharged piston twin.
flight-instruments piston-engine
edited 9 hours ago
David Richerby
9,92533578
asked 13 hours ago
PugzPugz
2,614827
$endgroup$
This is baffling me. Does anybody with experience with this type of indicator have any idea what the blue range of this gauge means?
It's mounted in a mock-up panel. I know nothing about where it originally came from, though it seems pretty clear that it's from a turbocharged piston twin.
flight-instruments piston-engine
flight-instruments piston-engine
edited 9 hours ago
David Richerby
9,92533578
asked 13 hours ago
PugzPugz
2,614827
edited 9 hours ago
David Richerby
9,92533578
asked 13 hours ago
PugzPugz
2,614827
edited 9 hours ago
David Richerby
9,92533578
edited 9 hours ago
David Richerby
9,92533578
edited 9 hours ago
David Richerby
9,92533578
9,92533578
asked 13 hours ago
PugzPugz
2,614827
asked 13 hours ago
PugzPugz
2,614827
asked 13 hours ago
PugzPugz
2,614827
2,614827
$begingroup$
It would help to know what aircraft this gauge is in
$endgroup$
– DeepSpace
13 hours ago
$begingroup$
@DeepSpace I'm sorry I have no idea. It is a standalone gauge we have just sitting around, but it looks pretty clearly to be from a turbocharged piston twin.
$endgroup$
– Pugz
13 hours ago
$begingroup$
Related: Why don't airplane turbo piston engines have boost control?
$endgroup$
– ymb1
13 hours ago
$begingroup$
For being a "standalone gauge we have just sitting around", it seems to be pretty well screwed into a panel of some sort.
$endgroup$
– FreeMan
12 hours ago
$begingroup$
@FreeMan yes it is! Mock up panel.
$endgroup$
– Pugz
10 hours ago
|
show 1 more comment
$begingroup$
It would help to know what aircraft this gauge is in
$endgroup$
– DeepSpace
13 hours ago
$begingroup$
@DeepSpace I'm sorry I have no idea. It is a standalone gauge we have just sitting around, but it looks pretty clearly to be from a turbocharged piston twin.
$endgroup$
– Pugz
13 hours ago
$begingroup$
Related: Why don't airplane turbo piston engines have boost control?
$endgroup$
– ymb1
13 hours ago
$begingroup$
For being a "standalone gauge we have just sitting around", it seems to be pretty well screwed into a panel of some sort.
$endgroup$
– FreeMan
12 hours ago
$begingroup$
@FreeMan yes it is! Mock up panel.
$endgroup$
– Pugz
10 hours ago
$begingroup$
It would help to know what aircraft this gauge is in
$endgroup$
– DeepSpace
13 hours ago
$begingroup$
It would help to know what aircraft this gauge is in
$endgroup$
– DeepSpace
13 hours ago
$begingroup$
@DeepSpace I'm sorry I have no idea. It is a standalone gauge we have just sitting around, but it looks pretty clearly to be from a turbocharged piston twin.
$endgroup$
– Pugz
13 hours ago
$begingroup$
@DeepSpace I'm sorry I have no idea. It is a standalone gauge we have just sitting around, but it looks pretty clearly to be from a turbocharged piston twin.
$endgroup$
– Pugz
13 hours ago
$begingroup$
Related: Why don't airplane turbo piston engines have boost control?
$endgroup$
– ymb1
13 hours ago
$begingroup$
Related: Why don't airplane turbo piston engines have boost control?
$endgroup$
– ymb1
13 hours ago
$begingroup$
For being a "standalone gauge we have just sitting around", it seems to be pretty well screwed into a panel of some sort.
$endgroup$
– FreeMan
12 hours ago
$begingroup$
For being a "standalone gauge we have just sitting around", it seems to be pretty well screwed into a panel of some sort.
$endgroup$
– FreeMan
12 hours ago
$begingroup$
@FreeMan yes it is! Mock up panel.
$endgroup$
– Pugz
10 hours ago
$begingroup$
@FreeMan yes it is! Mock up panel.
$endgroup$
– Pugz
10 hours ago
|
show 1 more comment
2 Answers
2
active
oldest
votes
$begingroup$
It's a manifold pressure limit with altitude. It relates to a limitation on the differential between ambient and total manifold pressure at different altitudes with turbocharged or supercharged engines; a limit on the amount of actual boost with altitude in other words, not the total pressure.
At 30000 ft, standard atmospheric pressure is only just under 9 inches. 20 inches on the gauge is 11 inches of boost above atmospheric.
At 20000 ft, atmospheric pressure is just under 14 inches, and you're limited to 35 inches, which is about 21 inches of boost.
Between 16000 ft and sea level, with atmospheric pressure between roughly 16 and 30 inches, the limitation is the red line of 40, which is anywhere from 10 to 24 inches of boost above atmospheric.
The increasing limitation in maximum boost with altitude is usually related to the reduced cylinder cooling ability of the thinning air with altitude, and the potential for detonation.
answered 12 hours ago
John KJohn K
21.1k12963
$endgroup$
add a comment |
$begingroup$
The blue scale indicates the maximum manifold pressure (MP) at a given altitude.
from sea level (SL) to 16000 ft: the maximum MP is 40 inHg (inches of mercury).
from 16000 ft to 30000 ft, the maximum MP goes down to 20 inHg.
The altitudes are barometric altitudes.
answered 13 hours ago
boglbogl
3,8071733
$endgroup$
$begingroup$
Do you have a reference such as a POH that describes this? What type have you seen this in?
$endgroup$
– Pugz
13 hours ago
2
$begingroup$
@Pugz, no, unfortunately not, but it is written on the gauge itself.
$endgroup$
– bogl
13 hours ago
$begingroup$
So this is indicating the maximum possible given existing atmosphere at a given altitude, not any sort of limit, but just for pilot reference to to compare to the altimeter?
$endgroup$
– Pugz
13 hours ago
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
It's a manifold pressure limit with altitude. It relates to a limitation on the differential between ambient and total manifold pressure at different altitudes with turbocharged or supercharged engines; a limit on the amount of actual boost with altitude in other words, not the total pressure.
At 30000 ft, standard atmospheric pressure is only just under 9 inches. 20 inches on the gauge is 11 inches of boost above atmospheric.
At 20000 ft, atmospheric pressure is just under 14 inches, and you're limited to 35 inches, which is about 21 inches of boost.
Between 16000 ft and sea level, with atmospheric pressure between roughly 16 and 30 inches, the limitation is the red line of 40, which is anywhere from 10 to 24 inches of boost above atmospheric.
The increasing limitation in maximum boost with altitude is usually related to the reduced cylinder cooling ability of the thinning air with altitude, and the potential for detonation.
answered 12 hours ago
John KJohn K
21.1k12963
$endgroup$
add a comment |
$begingroup$
It's a manifold pressure limit with altitude. It relates to a limitation on the differential between ambient and total manifold pressure at different altitudes with turbocharged or supercharged engines; a limit on the amount of actual boost with altitude in other words, not the total pressure.
At 30000 ft, standard atmospheric pressure is only just under 9 inches. 20 inches on the gauge is 11 inches of boost above atmospheric.
At 20000 ft, atmospheric pressure is just under 14 inches, and you're limited to 35 inches, which is about 21 inches of boost.
Between 16000 ft and sea level, with atmospheric pressure between roughly 16 and 30 inches, the limitation is the red line of 40, which is anywhere from 10 to 24 inches of boost above atmospheric.
The increasing limitation in maximum boost with altitude is usually related to the reduced cylinder cooling ability of the thinning air with altitude, and the potential for detonation.
answered 12 hours ago
John KJohn K
21.1k12963
$endgroup$
add a comment |
$begingroup$
It's a manifold pressure limit with altitude. It relates to a limitation on the differential between ambient and total manifold pressure at different altitudes with turbocharged or supercharged engines; a limit on the amount of actual boost with altitude in other words, not the total pressure.
At 30000 ft, standard atmospheric pressure is only just under 9 inches. 20 inches on the gauge is 11 inches of boost above atmospheric.
At 20000 ft, atmospheric pressure is just under 14 inches, and you're limited to 35 inches, which is about 21 inches of boost.
Between 16000 ft and sea level, with atmospheric pressure between roughly 16 and 30 inches, the limitation is the red line of 40, which is anywhere from 10 to 24 inches of boost above atmospheric.
The increasing limitation in maximum boost with altitude is usually related to the reduced cylinder cooling ability of the thinning air with altitude, and the potential for detonation.
answered 12 hours ago
John KJohn K
21.1k12963
$endgroup$
It's a manifold pressure limit with altitude. It relates to a limitation on the differential between ambient and total manifold pressure at different altitudes with turbocharged or supercharged engines; a limit on the amount of actual boost with altitude in other words, not the total pressure.
At 30000 ft, standard atmospheric pressure is only just under 9 inches. 20 inches on the gauge is 11 inches of boost above atmospheric.
At 20000 ft, atmospheric pressure is just under 14 inches, and you're limited to 35 inches, which is about 21 inches of boost.
Between 16000 ft and sea level, with atmospheric pressure between roughly 16 and 30 inches, the limitation is the red line of 40, which is anywhere from 10 to 24 inches of boost above atmospheric.
The increasing limitation in maximum boost with altitude is usually related to the reduced cylinder cooling ability of the thinning air with altitude, and the potential for detonation.
answered 12 hours ago
John KJohn K
21.1k12963
answered 12 hours ago
John KJohn K
21.1k12963
answered 12 hours ago
John KJohn K
21.1k12963
answered 12 hours ago
John KJohn K
21.1k12963
21.1k12963
add a comment |
add a comment |
$begingroup$
The blue scale indicates the maximum manifold pressure (MP) at a given altitude.
from sea level (SL) to 16000 ft: the maximum MP is 40 inHg (inches of mercury).
from 16000 ft to 30000 ft, the maximum MP goes down to 20 inHg.
The altitudes are barometric altitudes.
answered 13 hours ago
boglbogl
3,8071733
$endgroup$
$begingroup$
Do you have a reference such as a POH that describes this? What type have you seen this in?
$endgroup$
– Pugz
13 hours ago
2
$begingroup$
@Pugz, no, unfortunately not, but it is written on the gauge itself.
$endgroup$
– bogl
13 hours ago
$begingroup$
So this is indicating the maximum possible given existing atmosphere at a given altitude, not any sort of limit, but just for pilot reference to to compare to the altimeter?
$endgroup$
– Pugz
13 hours ago
add a comment |
$begingroup$
The blue scale indicates the maximum manifold pressure (MP) at a given altitude.
from sea level (SL) to 16000 ft: the maximum MP is 40 inHg (inches of mercury).
from 16000 ft to 30000 ft, the maximum MP goes down to 20 inHg.
The altitudes are barometric altitudes.
answered 13 hours ago
boglbogl
3,8071733
$endgroup$
$begingroup$
Do you have a reference such as a POH that describes this? What type have you seen this in?
$endgroup$
– Pugz
13 hours ago
2
$begingroup$
@Pugz, no, unfortunately not, but it is written on the gauge itself.
$endgroup$
– bogl
13 hours ago
$begingroup$
So this is indicating the maximum possible given existing atmosphere at a given altitude, not any sort of limit, but just for pilot reference to to compare to the altimeter?
$endgroup$
– Pugz
13 hours ago
add a comment |
$begingroup$
The blue scale indicates the maximum manifold pressure (MP) at a given altitude.
from sea level (SL) to 16000 ft: the maximum MP is 40 inHg (inches of mercury).
from 16000 ft to 30000 ft, the maximum MP goes down to 20 inHg.
The altitudes are barometric altitudes.
answered 13 hours ago
boglbogl
3,8071733
$endgroup$
The blue scale indicates the maximum manifold pressure (MP) at a given altitude.
from sea level (SL) to 16000 ft: the maximum MP is 40 inHg (inches of mercury).
from 16000 ft to 30000 ft, the maximum MP goes down to 20 inHg.
The altitudes are barometric altitudes.
answered 13 hours ago
boglbogl
3,8071733
edited 12 hours ago
answered 13 hours ago
boglbogl
3,8071733
answered 13 hours ago
boglbogl
3,8071733
answered 13 hours ago
boglbogl
3,8071733
3,8071733
$begingroup$
Do you have a reference such as a POH that describes this? What type have you seen this in?
$endgroup$
– Pugz
13 hours ago
2
$begingroup$
@Pugz, no, unfortunately not, but it is written on the gauge itself.
$endgroup$
– bogl
13 hours ago
$begingroup$
So this is indicating the maximum possible given existing atmosphere at a given altitude, not any sort of limit, but just for pilot reference to to compare to the altimeter?
$endgroup$
– Pugz
13 hours ago
add a comment |
$begingroup$
Do you have a reference such as a POH that describes this? What type have you seen this in?
$endgroup$
– Pugz
13 hours ago
2
$begingroup$
@Pugz, no, unfortunately not, but it is written on the gauge itself.
$endgroup$
– bogl
13 hours ago
$begingroup$
So this is indicating the maximum possible given existing atmosphere at a given altitude, not any sort of limit, but just for pilot reference to to compare to the altimeter?
$endgroup$
– Pugz
13 hours ago
$begingroup$
Do you have a reference such as a POH that describes this? What type have you seen this in?
$endgroup$
– Pugz
13 hours ago
$begingroup$
Do you have a reference such as a POH that describes this? What type have you seen this in?
$endgroup$
– Pugz
13 hours ago
2
2
$begingroup$
@Pugz, no, unfortunately not, but it is written on the gauge itself.
$endgroup$
– bogl
13 hours ago
$begingroup$
@Pugz, no, unfortunately not, but it is written on the gauge itself.
$endgroup$
– bogl
13 hours ago
$begingroup$
So this is indicating the maximum possible given existing atmosphere at a given altitude, not any sort of limit, but just for pilot reference to to compare to the altimeter?
$endgroup$
– Pugz
13 hours ago
$begingroup$
So this is indicating the maximum possible given existing atmosphere at a given altitude, not any sort of limit, but just for pilot reference to to compare to the altimeter?
$endgroup$
– Pugz
13 hours ago
add a comment |
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$begingroup$
It would help to know what aircraft this gauge is in
$endgroup$
– DeepSpace
13 hours ago
$begingroup$
@DeepSpace I'm sorry I have no idea. It is a standalone gauge we have just sitting around, but it looks pretty clearly to be from a turbocharged piston twin.
$endgroup$
– Pugz
13 hours ago
$begingroup$
Related: Why don't airplane turbo piston engines have boost control?
$endgroup$
– ymb1
13 hours ago
$begingroup$
For being a "standalone gauge we have just sitting around", it seems to be pretty well screwed into a panel of some sort.
$endgroup$
– FreeMan
12 hours ago
$begingroup$
@FreeMan yes it is! Mock up panel.
$endgroup$
– Pugz
10 hours ago