Blackbird's thrust question
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Hi Brian,
The only way I see to get a copy of this is through the CIA. It is declassified and is listed as an article on their web site. If you are interested, I could go through the process to attempt to get a copy and see what it says.
It would be interesting to get hold of Brown, William H. “J58/SR-71 Propulsion Integration,” Studies in Intelligence 26:2 (Summer 1982), 15-23. Probably be able to shed some light.
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Hello Lyman,
I agree with your reasoning.
The increase in engine thrust at the afterburner nozzle (gross) is, I believe although not quoted, of the same order as the airflow increase. I guess the a/b temperature did not change significantly, otherwise the jet velocity contribution to the engine thrust would have had a more noticeable effect on the engine thrust.
Thanks for the stimulation.
I agree with your reasoning.
The increase in engine thrust at the afterburner nozzle (gross) is, I believe although not quoted, of the same order as the airflow increase. I guess the a/b temperature did not change significantly, otherwise the jet velocity contribution to the engine thrust would have had a more noticeable effect on the engine thrust.
Thanks for the stimulation.
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Disregard previous post (tongue-in-cheek or not) - this stuff's fascinating!
Ike - if you haven't worked it out yet, the so-called "old-timers" always have the best stories.
Ike - if you haven't worked it out yet, the so-called "old-timers" always have the best stories.
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Actually, most of the contributors to this thread tend to be the most self-effacing on PPRuNe. And in this case, they really do have the best stories.
I
you not - if you ignore this thread, you're missing out.
I
you not - if you ignore this thread, you're missing out.
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Originally Posted by DozyWannabe
Ike - if you haven't worked it out yet, the so-called "old-timers" always have the best stories
You seemed to be estonished when I wrote some months ago that the first AF447 threads were the best : Old-timers were the first who were able to analyse the few informations we had before the black boxes were found.
I am glad to read your last post
TNX, Rouli, we dinosaurs needed that!
I joined the old farts after the AF447 accident because I have always been interested in an accident involving a FBW aircraft. Being in the "charter members" of the first operational aircraft with full FBW, I felt I could both learn and contribute. I have my engineer diploma and then a lot of hours in real planes, and remember there's no such thing as a "dumb fighter pilot".
We may have to search the archives, but I suggested early on once the wreckage pattern was shown that it seemed the thing hit in a classic "deep stall". Turned out it wasn't quite that simple, but humans and not the aero characteristics of the jet caused the crash.
I continue to value the contributions and experience of the old farts when they post on these forums.
I joined the old farts after the AF447 accident because I have always been interested in an accident involving a FBW aircraft. Being in the "charter members" of the first operational aircraft with full FBW, I felt I could both learn and contribute. I have my engineer diploma and then a lot of hours in real planes, and remember there's no such thing as a "dumb fighter pilot".
We may have to search the archives, but I suggested early on once the wreckage pattern was shown that it seemed the thing hit in a classic "deep stall". Turned out it wasn't quite that simple, but humans and not the aero characteristics of the jet caused the crash.
I continue to value the contributions and experience of the old farts when they post on these forums.
multi-cycle motor
While we were examining Dr. Abernathy's neat way to keep the motor going above 3.0 M, GE was testing their new motor that implements some of the same concepts and reflects my view of the annular bypass.
"Superjet" variable cycle jet engine could power future fighter aircraft
Worth a look to see motor concepts of the next century compared with what the good Doctor did 50 years ago!
My own view is not to have an extra "fan" disk but use the outside duct as a true "ram jet" and same sorta inlet configuration the Blackbird had. CAUTION!! Don't get all excited, Lyman.
"Superjet" variable cycle jet engine could power future fighter aircraft
Worth a look to see motor concepts of the next century compared with what the good Doctor did 50 years ago!
My own view is not to have an extra "fan" disk but use the outside duct as a true "ram jet" and same sorta inlet configuration the Blackbird had. CAUTION!! Don't get all excited, Lyman.
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roulishollandais
I'd say about half the input turned out to be right in the early threads. The discussion started to go somewhere after the recovery of the flight recorders. I don't think the age of the contributors was as big a deal as it is in this thread though...
I'd say about half the input turned out to be right in the early threads. The discussion started to go somewhere after the recovery of the flight recorders. I don't think the age of the contributors was as big a deal as it is in this thread though...
Yes Doze, it's a sobering thought that the most rookie pilot or engineer ever involved in supersonic civil transport must be at least in his/her fifties. And roughly the same applies to Mach 3+ in the military?
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I hope he won't mind me saying this, but given that Clive - no rookie at the time - comes across as eternally engaged and excited by the subject (not to mention sprightly in general) and is clearly keeping abreast of things, it would appear that working on projects of that ilk can confer a certain extended "youthful" outlook. Long may it continue!
The M3+ military projects were effectively rendered obsolete much faster by the advent of the space programme. I'm sure that the engineers to come that are worth their salt will be smart enough to engage with their predecessors and their work. I barely understood half of the stuff in this thread and I'm still hooked!
The M3+ military projects were effectively rendered obsolete much faster by the advent of the space programme. I'm sure that the engineers to come that are worth their salt will be smart enough to engage with their predecessors and their work. I barely understood half of the stuff in this thread and I'm still hooked!
Last edited by DozyWannabe; 22nd Feb 2013 at 21:39.
Last SR-71 pilot I had dinner with was my age at the time - 40 years old when he lost an engine and landed at my base.. A student of mine 5 years younger flew the beast over Libya in 1986 ( El Dorado Canyon, I believe - Brian Shul), so would have been in late 30's.
Only the shuttle guys were lots older than the early days of NASA. My roomie flew first hop back in '87 or '88, and would have been in his late forties, but had been selected about 8 years earlier. He then flew on the MIR about 8 years after that, so figure it out.
Make no mistake, experience counts. However, that experience must involve a few instances of abnormal systems or situations. Our profession exposed us to many while we were very young, and they turned the keys over to us when we were 22 or 23 years old. Think about a troop in his late 20's flying a Raptor or Lightning that costs about as much as many airliners.
Only the shuttle guys were lots older than the early days of NASA. My roomie flew first hop back in '87 or '88, and would have been in his late forties, but had been selected about 8 years earlier. He then flew on the MIR about 8 years after that, so figure it out.
Make no mistake, experience counts. However, that experience must involve a few instances of abnormal systems or situations. Our profession exposed us to many while we were very young, and they turned the keys over to us when we were 22 or 23 years old. Think about a troop in his late 20's flying a Raptor or Lightning that costs about as much as many airliners.
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Wasn't that because they erred heavily on the side of caution regarding the effects of zero-G on health and fitness? I'm assuming that because Skylab gave them hard data to work with it became less of an issue by the time of STS-1.
Actually, Doze, the problem had to do with the snail's pace of the shuttle program and not physical condition.
Cooper in Mercury was 36 and White was 35 in the Gemini spacewalk. I knew White, as his brother was a classmate in my squad at USAFA and was the one that convinced me I could make it if I tried.
The Mercury, Gemini and Apollo guys moved ahead very quickly. From selection to first flight was three or four years at most. Shuttle was 7, 8 9 years.
My roomie was selected at age 40 and flew 9 years later! Of course, he had to stand down for two years due to the Challenger disaster.
but I digress......
Cooper in Mercury was 36 and White was 35 in the Gemini spacewalk. I knew White, as his brother was a classmate in my squad at USAFA and was the one that convinced me I could make it if I tried.
The Mercury, Gemini and Apollo guys moved ahead very quickly. From selection to first flight was three or four years at most. Shuttle was 7, 8 9 years.
My roomie was selected at age 40 and flew 9 years later! Of course, he had to stand down for two years due to the Challenger disaster.
but I digress......
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gums
Fascinating stuff, but when one reads the article it becomes clear that the engine is for military use. Cutting down the airflow to increase thrust at take-off is the last thing you want to do if your problem is airfield noise!
Dozy
Knock it off Joe, it is becoming embarrassing - besides, the spirit is willing but the flesh is weak
Worth a look to see motor concepts of the next century compared with what the good Doctor did 50 years ago!
Dozy
Knock it off Joe, it is becoming embarrassing - besides, the spirit is willing but the flesh is weak
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Well here's the Hollywood pitch:
PpruNe pensioners crowd-source a replica SR-71 from souvenir paper-weight components, a junk airframe and lashings of old-timer Skunk Works / Concorde physics. Having learned that a craven State Department is delaying vital surveillance of a rogue state nuclear programme, Gums battles his demons to eventually dust off his G-Suit for One Last Mission, sanctioned only by PPruNe, and to finally fly this historic marvel. Suspense builds, because the audience know that PpruNe thread-lurkers from Iran have just completed a YF-12 based on the same data.
Gums gets the crucial recon. pictures but, unarmed of course, finds the YF-12 on his tail. Just when all seems lost he gambles on the expertise of his PpruNe pals, and pulls a manoeuvre just beyond the stated structural limits of the airframe. The YF-12 has to pull the same manoeuvre to achieve missile-lock, and comes apart. Credits roll over a PpruNe guard of honour at the culmination of Gum's Presidential ticker tape parade.
In flashback, the young CliveL will be played by Simon Pegg, based on his performance as Scotty in the Star Trek reboot...
PpruNe pensioners crowd-source a replica SR-71 from souvenir paper-weight components, a junk airframe and lashings of old-timer Skunk Works / Concorde physics. Having learned that a craven State Department is delaying vital surveillance of a rogue state nuclear programme, Gums battles his demons to eventually dust off his G-Suit for One Last Mission, sanctioned only by PPruNe, and to finally fly this historic marvel. Suspense builds, because the audience know that PpruNe thread-lurkers from Iran have just completed a YF-12 based on the same data.
Gums gets the crucial recon. pictures but, unarmed of course, finds the YF-12 on his tail. Just when all seems lost he gambles on the expertise of his PpruNe pals, and pulls a manoeuvre just beyond the stated structural limits of the airframe. The YF-12 has to pull the same manoeuvre to achieve missile-lock, and comes apart. Credits roll over a PpruNe guard of honour at the culmination of Gum's Presidential ticker tape parade.
In flashback, the young CliveL will be played by Simon Pegg, based on his performance as Scotty in the Star Trek reboot...
Last edited by robdean; 23rd Feb 2013 at 12:10.
Good grief, Robs!
@ Clive: Yeah, and the ADVENT uses the extra air for a higher bypass ratio and not to help the burner. Seems to make it more like the TF-41, which gave the Sluf super range/loiter time compared to the Double Ugly, Thud, Hun, et al.
@ Clive: Yeah, and the ADVENT uses the extra air for a higher bypass ratio and not to help the burner. Seems to make it more like the TF-41, which gave the Sluf super range/loiter time compared to the Double Ugly, Thud, Hun, et al.
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gums
One thing I do know is that during the Apollo era, the late, great Alan Shepard was at the top extreme of what NASA would allow when he commanded Apollo 14 at 47 years of age. Because the surviving Mercury 7 tended to retire during the Apollo era in their early 40s I'd wager that he was actually probably over what they originally intended, but Deke Slayton didn't have the heart to deny him after fighting his way back to flight status following experimental surgery for Ménière's disease - which had until then left him grounded.
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Hi gums,
Thanks for the ADVENT video, it is indeed rather interesting. IMO, It is the wave of the future for military combat aircraft engines.
GE Aviation completed testing its engine core for the ADaptive Versatile ENgine Technology (ADVENT) program with the U.S. Air Force Research Laboratory on Feb. 6, achieving the highest combination of compressor and turbine temperatures ever recorded in aviation history.
The accomplishment is a result of GE's most advanced core propulsion technologies including lightweight, heat-resistant ceramic matrix composite (CMC) materials. These core technologies, along with an adaptive low pressure spool, result in a 25 percent improvement in fuel efficiency, a 30 percent increase in operating range and a five-to-10 percent improvement in thrust compared to today's fixed-cycle engines.
I do want to point out this technology is not new and has been in the works for a long time. Following initial studies by Gerhard Neumann in the 1960s, GE's YJ101 was the first full engine to demonstrate variable cycle capabilities in 1976 (see report below). The YJ101 was the forerunner of the F404 engine for the Navy's F-18 fighter.
Access forbidden!
The next engine to use the variable technology was the GE YF120 engine under a demonstration contract for the Advanced Tactical Fighter (ATF). An engine is on display at the USAF Museum and was one of two YF120 engines installed on the YF-23, Northrop-McDonnell Douglas' entry to what is the F-22 Raptor fighter. The contest was lost to Lockheed YF-22 and P&W's F119 engine.
The technology then carried over to the Joint Strike Fighter (JSF)(F-35) program where a collaboration between GE Aircraft Engines, Allison Advanced Development Company, and Rolls-Royce. Allison provided components and some technology for the engine core and low pressure turbine; Rolls-Royce designed and manufactured the fan module, but the overall design was based on the variable cycle YF-120 engine. Again though, P&W was awarded the engine contract using the F119 engine.
Thanks for the ADVENT video, it is indeed rather interesting. IMO, It is the wave of the future for military combat aircraft engines.
GE Aviation completed testing its engine core for the ADaptive Versatile ENgine Technology (ADVENT) program with the U.S. Air Force Research Laboratory on Feb. 6, achieving the highest combination of compressor and turbine temperatures ever recorded in aviation history.
The accomplishment is a result of GE's most advanced core propulsion technologies including lightweight, heat-resistant ceramic matrix composite (CMC) materials. These core technologies, along with an adaptive low pressure spool, result in a 25 percent improvement in fuel efficiency, a 30 percent increase in operating range and a five-to-10 percent improvement in thrust compared to today's fixed-cycle engines.
I do want to point out this technology is not new and has been in the works for a long time. Following initial studies by Gerhard Neumann in the 1960s, GE's YJ101 was the first full engine to demonstrate variable cycle capabilities in 1976 (see report below). The YJ101 was the forerunner of the F404 engine for the Navy's F-18 fighter.
Access forbidden!
The next engine to use the variable technology was the GE YF120 engine under a demonstration contract for the Advanced Tactical Fighter (ATF). An engine is on display at the USAF Museum and was one of two YF120 engines installed on the YF-23, Northrop-McDonnell Douglas' entry to what is the F-22 Raptor fighter. The contest was lost to Lockheed YF-22 and P&W's F119 engine.
The technology then carried over to the Joint Strike Fighter (JSF)(F-35) program where a collaboration between GE Aircraft Engines, Allison Advanced Development Company, and Rolls-Royce. Allison provided components and some technology for the engine core and low pressure turbine; Rolls-Royce designed and manufactured the fan module, but the overall design was based on the variable cycle YF-120 engine. Again though, P&W was awarded the engine contract using the F119 engine.