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Author Topic: SR-72?  (Read 141776 times)

Offline RavenOne

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Re: SR-72?
« Reply #300 on: October 12, 2017, 10:22:48 am »
'I have a suspicion everything on this project is a bit further ahead than announced'

By 30 years!

Chris

Hi C

Twigged from your description and subsequent artists impression of that night that it was an NKC-135 refueling said vehicle such as from Edwards...judging by the nose.

Three decades of development now that reminds me laughingly of the opening  dialogue between Archangel and Senator Dietz in the first ever episode of Airwolf, where Archangel describes the orgins of Airwolf development which started after the failed Bay of Pigs invasion.

cheers


Offline marauder2048

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Re: SR-72?
« Reply #301 on: October 12, 2017, 11:53:38 am »
'I have a suspicion everything on this project is a bit further ahead than announced'

By 30 years!

Chris

*sigh*...If only DARPA actually worked that way...*grumble*


Offline Flyaway

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Re: SR-72?
« Reply #302 on: October 12, 2017, 02:06:40 pm »
'I have a suspicion everything on this project is a bit further ahead than announced'

By 30 years!

Chris

*sigh*...If only DARPA actually worked that way...*grumble*

I still wonder if they’ve ever flown any high speed experimental aircraft over recent decades.

Offline sferrin

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Re: SR-72?
« Reply #303 on: October 12, 2017, 04:25:21 pm »
'I have a suspicion everything on this project is a bit further ahead than announced'

By 30 years!

Chris

*sigh*...If only DARPA actually worked that way...*grumble*

My admittedly limited experience suggests they try something, and whether it's successful or not, more often than not just file the information where it's left to rot.
"DARPA Hard"  It ain't what it use to be.

Offline Rhinocrates

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Re: SR-72?
« Reply #304 on: October 12, 2017, 05:24:54 pm »
There's this interesting interview with Sharon Weinberger on her book, Imagineers of War.

http://www.thespaceshow.com/show/20-aug-2017/broadcast-2969-sharon-weinberger

She says that the line between success and failure is quite fuzzy, with "failed" projects like NASP and Q nonetheless feeding on to later developments. She does however mention that DARPA lacks an internal historian, which affects its institutional memory.

Pure uninformed speculation on my part, but it may be kinda sorta perhaps possible - not proven - that if some rumours are true, a PDE powered 'Aurora' may have flown, but the acoustic effects of the PDE engines caused severe MRO problems, turning it into a very expensive and short-lived hangar queen that never saw service. In British Secret Projects: Jet Fighters Since 1950 Tony Buttler notes that
the acoustic effects of rockets on the airframe in the Fairey F.155, Saunders-Roe P.187 and Vickers Type 559 raised serious concerns. Then there's the huge exhaust ramp on NASP and many other hypersonic aircraft renderings that must have presented huge heating problems and is notably absent from the SR-72 renderings.

You don't hear much about PDEs any more, but Aerojet Rocketdyne has been investigating 'Rotating Detonation Engines':

http://aviationweek.com/print/technology/aerojet-rocketdyne-explores-detonation-engine-options

... though now they're seeking to demonstrate combined-cycle.
« Last Edit: October 12, 2017, 05:43:57 pm by Rhinocrates »
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Offline Flyaway

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Re: SR-72?
« Reply #305 on: October 13, 2017, 04:54:27 am »
THE ENIGMATIC SR-72 AND THE PALMDALE SIGHTINGS: WHAT DO THEY TELL US ABOUT AMERICA’S SECRET HYPERSONIC PROGRAM?

https://theaviationist.com/2017/10/12/the-enigmatic-sr-72-and-the-palmdale-sightings-what-do-they-tell-us-about-americas-secret-hypersonic-program/

Offline aliensporebomb

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Re: SR-72?
« Reply #306 on: October 13, 2017, 12:50:54 pm »
There's this interesting interview with Sharon Weinberger on her book, Imagineers of War.

http://www.thespaceshow.com/show/20-aug-2017/broadcast-2969-sharon-weinberger

She says that the line between success and failure is quite fuzzy, with "failed" projects like NASP and Q nonetheless feeding on to later developments. She does however mention that DARPA lacks an internal historian, which affects its institutional memory.

Pure uninformed speculation on my part, but it may be kinda sorta perhaps possible - not proven - that if some rumours are true, a PDE powered 'Aurora' may have flown, but the acoustic effects of the PDE engines caused severe MRO problems, turning it into a very expensive and short-lived hangar queen that never saw service. In British Secret Projects: Jet Fighters Since 1950 Tony Buttler notes that
the acoustic effects of rockets on the airframe in the Fairey F.155, Saunders-Roe P.187 and Vickers Type 559 raised serious concerns. Then there's the huge exhaust ramp on NASP and many other hypersonic aircraft renderings that must have presented huge heating problems and is notably absent from the SR-72 renderings.

You don't hear much about PDEs any more, but Aerojet Rocketdyne has been investigating 'Rotating Detonation Engines':

http://aviationweek.com/print/technology/aerojet-rocketdyne-explores-detonation-engine-options

... though now they're seeking to demonstrate combined-cycle.

That's a thought for sure - One story going around back in the day was that a witness to Aurora (Jim Goodall?) claimed the during a ground test the engines could be heard from 19 miles away.  The sheer sound pressure levels alone would make anyone on the flightline deaf.  Who knows what stress that would have put on an airframe?  If it existed as a test program this would have been a brute force way to achieve high speed cruise but later ideas are probably better.  As time passes we might hear more about that but it's obvious the SR-72 is using a different method.


Yes I really have a domain called aliensporebomb dot com.

Offline Flyaway

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Re: SR-72?
« Reply #307 on: October 13, 2017, 01:15:34 pm »
There's this interesting interview with Sharon Weinberger on her book, Imagineers of War.

http://www.thespaceshow.com/show/20-aug-2017/broadcast-2969-sharon-weinberger

She says that the line between success and failure is quite fuzzy, with "failed" projects like NASP and Q nonetheless feeding on to later developments. She does however mention that DARPA lacks an internal historian, which affects its institutional memory.

Pure uninformed speculation on my part, but it may be kinda sorta perhaps possible - not proven - that if some rumours are true, a PDE powered 'Aurora' may have flown, but the acoustic effects of the PDE engines caused severe MRO problems, turning it into a very expensive and short-lived hangar queen that never saw service. In British Secret Projects: Jet Fighters Since 1950 Tony Buttler notes that
the acoustic effects of rockets on the airframe in the Fairey F.155, Saunders-Roe P.187 and Vickers Type 559 raised serious concerns. Then there's the huge exhaust ramp on NASP and many other hypersonic aircraft renderings that must have presented huge heating problems and is notably absent from the SR-72 renderings.

You don't hear much about PDEs any more, but Aerojet Rocketdyne has been investigating 'Rotating Detonation Engines':

http://aviationweek.com/print/technology/aerojet-rocketdyne-explores-detonation-engine-options

... though now they're seeking to demonstrate combined-cycle.

That's a thought for sure - One story going around back in the day was that a witness to Aurora (Jim Goodall?) claimed the during a ground test the engines could be heard from 19 miles away.  The sheer sound pressure levels alone would make anyone on the flightline deaf.  Who knows what stress that would have put on an airframe?  If it existed as a test program this would have been a brute force way to achieve high speed cruise but later ideas are probably better.  As time passes we might hear more about that but it's obvious the SR-72 is using a different method.

I wonder what the project really was called being as Aurora was a line item in the B-2 budget.

By the way this book is in my to read pile, I really must hurry up and get to it.
« Last Edit: October 13, 2017, 01:18:05 pm by Flyaway »

Offline DrRansom

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Re: SR-72?
« Reply #308 on: October 13, 2017, 01:51:47 pm »
THE ENIGMATIC SR-72 AND THE PALMDALE SIGHTINGS: WHAT DO THEY TELL US ABOUT AMERICA’S SECRET HYPERSONIC PROGRAM?

https://theaviationist.com/2017/10/12/the-enigmatic-sr-72-and-the-palmdale-sightings-what-do-they-tell-us-about-americas-secret-hypersonic-program/

This is a rather silly article, which adds more confusion than anything else.

Offline marauder2048

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Re: SR-72?
« Reply #309 on: October 13, 2017, 07:49:09 pm »
You don't hear much about PDEs any more, but Aerojet Rocketdyne has been investigating 'Rotating Detonation Engines':

http://aviationweek.com/print/technology/aerojet-rocketdyne-explores-detonation-engine-options

... though now they're seeking to demonstrate combined-cycle.

Above Mach 3-4, PDEs lose their thermal efficiency advantage over other
cycles.

Having said that, one of the inferred knees  (from Letsinger 2012)
in the survivability curve is a Mach 2.5 - 3.5 cruiser
with significant signature reduction.

The other is a Mach 5 - 6 cruiser with moderate signature reduction.

Offline bobbymike

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Re: SR-72?
« Reply #310 on: October 13, 2017, 10:33:56 pm »
Do you have the full PDF?
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Offline Dragon029

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Re: SR-72?
« Reply #311 on: October 14, 2017, 02:44:11 am »
http://www.au.af.mil/au/awc/awcgate/awc/2012_letsinger.pdf

At least one of the Skunk Works slides is from Ellrodt, “The Value of Speed/Altitude and Signature for Survivability,” Lockheed Martin Releasable Power Point Presentation, Oct 24, 2011,
Slide 15.
, but I can't find that on the web.

Offline Flyaway

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Re: SR-72?
« Reply #312 on: October 14, 2017, 02:50:52 am »
Related article.

USAF searching for hypersonic vehicle materials

Quote
The US Air Force Research Laboratory is searching for leading edge materials for reusable and expendable hypersonic vehicles to support its high speed strike weapon programme.

Quote
Air Force Materiel Command will consider thermal performance as it selects the material, according to the $2.3 million contract award to Integration Innovation posted 27 September on the Federal Business Opportunities website. Based in Huntsville, Alabama, Integration Innovation Integration has previously worked with the Defense Department and NASA on thermal protection systems supporting hypersonic vehicles.

“The objective of the RX hypersonics programme is to provide a range of materials and processing options for future hypersonic vehicles,” an AFRL spokesman said in a 10 October statement to FlightGlobal.

Leading edges refer to the surfaces that first come in contact at hypersonic speed with the super-heated airflow, such as as the front of the nose, wings and empennage surfaces.

The USAF has proposed $31.2 million in fiscal year 2018 to focus research on high temperature aerospace materials and hypersonics. Budget documents also mention plans to improve fabrication of materials required for expendable hypersonic applications. The FY2018 budget proposal details plans for both re-usable and expendable hypersonic vehicles, including limited life intelligence, surveillance, and reconnaissance vehicles.

https://www.flightglobal.com/news/articles/usaf-searching-for-hypersonic-vehicle-materials-442171/

Offline George Allegrezza

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Re: SR-72?
« Reply #313 on: October 14, 2017, 05:56:53 am »
That's a thought for sure - One story going around back in the day was that a witness to Aurora (Jim Goodall?) claimed the during a ground test the engines could be heard from 19 miles away.  The sheer sound pressure levels alone would make anyone on the flightline deaf.  Who knows what stress that would have put on an airframe?  If it existed as a test program this would have been a brute force way to achieve high speed cruise but later ideas are probably better.  As time passes we might hear more about that but it's obvious the SR-72 is using a different method.

Air turborockets are attractive propulsion systems for some vehicle types, and should in theory be spectacularly loud.  There was a lot of experimental work done on those in the 1960s and 1970s.  Thus there could have been a technology base to exploit if they were incorporated into test vehicles in the Copper Canyon/NASP/"Aurora" period.

Having said that . . a ground test, if in fact it happened as described, is not the same thing as testing an installed system in a flight vehicle.  Also, plain old rockets can be heard from very far away -- a Shuttle launch had a pretty big acoustical footprint, for example.

Offline Flyaway

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Re: SR-72?
« Reply #314 on: October 14, 2017, 07:36:31 am »
One of the numerous articles I’ve seen about this seemed to think the engine in the FRV would be based on the F-135, has this been stated anywhere else?