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Flight Altitude Restriction and Supercruise



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aw2007
PostPosted: Aug 22, 2012 - 12:18 AM Reply with quote Back to top
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According to an article I read in Aviation Week a couple of years ago, the Max supercruise speed is M 1.82 and normal supercruise speed is M 1.5, both take place above 50000 ft. Given the current altitude restriction of 44000 ft, which hopefully will be lifted when the valve of the anti-G vest is replaced by the end of the year; Does anyone know how much, if any, effect the restriction might have on the plane's ability to supercruise? Please note that I'm not soliciting, nor am I expecting any classified info on this subject. Just looking to learn something out of meaningful discussion.
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Atle
PostPosted: Aug 22, 2012 - 12:35 PM Reply with quote Back to top
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aw2007 wrote:
According to an article I read in Aviation Week a couple of years ago, the Max supercruise speed is M 1.82 and normal supercruise speed is M 1.5, both take place above 50000 ft. Given the current altitude restriction of 44000 ft, which hopefully will be lifted when the valve of the anti-G vest is replaced by the end of the year; Does anyone know how much, if any, effect the restriction might have on the plane's ability to supercruise? Please note that I'm not soliciting, nor am I expecting any classified info on this subject. Just looking to learn something out of meaningful discussion.


Either that article was incorrect or you remember it wrong. The F-22 can supercruise at M1.82 and reach an altitude of over 50,000 ft, but not at the same time. Actually, best supercruise performance is supposedly at 35,000 ft.
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fiskerwad
PostPosted: Aug 22, 2012 - 01:50 PM Reply with quote Back to top
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Atle wrote:
aw2007 wrote:
According to an article I read in Aviation Week a couple of years ago, the Max supercruise speed is M 1.82 and normal supercruise speed is M 1.5, both take place above 50000 ft. Given the current altitude restriction of 44000 ft, which hopefully will be lifted when the valve of the anti-G vest is replaced by the end of the year; Does anyone know how much, if any, effect the restriction might have on the plane's ability to supercruise? Please note that I'm not soliciting, nor am I expecting any classified info on this subject. Just looking to learn something out of meaningful discussion.


Either that article was incorrect or you remember it wrong. The F-22 can supercruise at M1.82 and reach an altitude of over 50,000 ft, but not at the same time. Actually, best supercruise performance is supposedly at 35,000 ft.


The article was probably this one:

Aviation Week (Feb 8/09) – F-22 Design Shows More Than Expected. Desired radar signature from certain critical angles is -40 dBsm., supercruise at Mach 1.78 rather than Mach 1.5, better acceleration, operation from about 65,000 feet using afterburner, 5% greater range from its APG-77 AESA radar.

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aw2007
PostPosted: Aug 22, 2012 - 02:09 PM Reply with quote Back to top
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fiskerwad wrote:
Atle wrote:
aw2007 wrote:
According to an article I read in Aviation Week a couple of years ago, the Max supercruise speed is M 1.82 and normal supercruise speed is M 1.5, both take place above 50000 ft. Given the current altitude restriction of 44000 ft, which hopefully will be lifted when the valve of the anti-G vest is replaced by the end of the year; Does anyone know how much, if any, effect the restriction might have on the plane's ability to supercruise? Please note that I'm not soliciting, nor am I expecting any classified info on this subject. Just looking to learn something out of meaningful discussion.


Either that article was incorrect or you remember it wrong. The F-22 can supercruise at M1.82 and reach an altitude of over 50,000 ft, but not at the same time. Actually, best supercruise performance is supposedly at 35,000 ft.


The article was probably this one:

Aviation Week (Feb 8/09) – F-22 Design Shows More Than Expected. Desired radar signature from certain critical angles is -40 dBsm., supercruise at Mach 1.78 rather than Mach 1.5, better acceleration, operation from about 65,000 feet using afterburner, 5% greater range from its APG-77 AESA radar.

fisk


Yes, Fisk, that is the article I was referring to. Atle: Interesting. May I ask where you got your info from?
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Atle
PostPosted: Aug 22, 2012 - 03:25 PM Reply with quote Back to top
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aw2007 wrote:
fiskerwad wrote:


The article was probably this one:

Aviation Week (Feb 8/09) – F-22 Design Shows More Than Expected. Desired radar signature from certain critical angles is -40 dBsm., supercruise at Mach 1.78 rather than Mach 1.5, better acceleration, operation from about 65,000 feet using afterburner, 5% greater range from its APG-77 AESA radar.

fisk


Yes, Fisk, that is the article I was referring to. Atle: Interesting. May I ask where you got your info from?


You do realise that the quote contradicts your original statement?

My data is from the US Airforce:



As for the original question, no, the altitude restrictions has not impaired the supercruise capability of the F-22.
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wrightwing
PostPosted: Aug 22, 2012 - 04:20 PM Reply with quote Back to top
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The F-22 can supercruise at a wide variety of altitudes, including at extreme high altitudes. The speed may change slightly, due to the effects of altitude on Mach numbers.
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sferrin
PostPosted: Aug 22, 2012 - 05:01 PM Reply with quote Back to top
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Atle wrote:
aw2007 wrote:
According to an article I read in Aviation Week a couple of years ago, the Max supercruise speed is M 1.82 and normal supercruise speed is M 1.5, both take place above 50000 ft. Given the current altitude restriction of 44000 ft, which hopefully will be lifted when the valve of the anti-G vest is replaced by the end of the year; Does anyone know how much, if any, effect the restriction might have on the plane's ability to supercruise? Please note that I'm not soliciting, nor am I expecting any classified info on this subject. Just looking to learn something out of meaningful discussion.


Either that article was incorrect or you remember it wrong. The F-22 can supercruise at M1.82 and reach an altitude of over 50,000 ft, but not at the same time. Actually, best supercruise performance is supposedly at 35,000 ft.


Where'd you hear that? Smells like BS. There's at least one account out there of a pilot talking about supercruising at Mach 1.9 at 60,000ft+. Designing it for supercruising at 60,000ft would be totally pointless if it required AB to do it. As for that graph, the DoD almost always SEVERLY understates things in "official" documents. For example the Seawolf SSN is listed as max speed of 25 knots and max depth of 800 ft.

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Atle
PostPosted: Aug 22, 2012 - 07:44 PM Reply with quote Back to top
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sferrin wrote:
Where'd you hear that? Smells like BS. There's at least one account out there of a pilot talking about supercruising at Mach 1.9 at 60,000ft+. Designing it for supercruising at 60,000ft would be totally pointless if it required AB to do it. As for that graph, the DoD almost always SEVERLY understates things in "official" documents. For example the Seawolf SSN is listed as max speed of 25 knots and max depth of 800 ft.


It comes from Major General Charles R Davis, USAF, at an official presentation.

http://www.florida-edc.org/getmedia/bfa ... ept08.aspx
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PostPosted: Aug 22, 2012 - 08:21 PM Reply with quote Back to top
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sferrin wrote:
For example the Seawolf SSN is listed as max speed of 25 knots and max depth of 800 ft.


Haha, I love it whenever I read press reports that state submarines can dive to 800ft, it's like saying a Ferrari can reach 60mph.

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wrightwing
PostPosted: Aug 22, 2012 - 08:36 PM Reply with quote Back to top
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Atle wrote:

It comes from Major General Charles R Davis, USAF, at an official presentation.

http://www.florida-edc.org/getmedia/bfa ... ept08.aspx


That's a pretty vanilla presentation. You're not going to see an unclassified presentation, with the full flight envelope of the F-22.
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wrightwing
PostPosted: Aug 22, 2012 - 08:36 PM Reply with quote Back to top
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PhillyGuy wrote:
sferrin wrote:
For example the Seawolf SSN is listed as max speed of 25 knots and max depth of 800 ft.


Haha, I love it whenever I read press reports that state submarines can dive to 800ft, it's like saying a Ferrari can reach 60mph.


And that's just in first gear. Wink
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fiskerwad
PostPosted: Aug 23, 2012 - 12:03 AM Reply with quote Back to top
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wrightwing wrote:
Atle wrote:

It comes from Major General Charles R Davis, USAF, at an official presentation.

http://www.florida-edc.org/getmedia/bfa ... ept08.aspx


That's a pretty vanilla presentation. You're not going to see an unclassified presentation, with the full flight envelope of the F-22.


What did I miss? The presentation was F-35 to a business group? Where was the F-22 data?
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SpudmanWP
PostPosted: Aug 23, 2012 - 12:29 AM Reply with quote Back to top
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Page 14

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fiskerwad
PostPosted: Aug 23, 2012 - 07:23 PM Reply with quote Back to top
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SpudmanWP wrote:
Page 14


Thanks, I guess the numbers quoted were just extracted from the graph?
Shaky.
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SpudmanWP
PostPosted: Aug 23, 2012 - 07:58 PM Reply with quote Back to top
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Looks that way.

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