F-35 Cancelled, then what ?
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Originally Posted by GreenKnight121
...mainstay of a dozen nations' air power for decades, an extremely successful aircraft from carriers as well as land bases, rugged and dependable, easily upgradable through several decades, world-beating for its era, and listed by almost everyone as an all-time classic!
-RP
A funny thing, PhilipG, the F-35 fanatics are a little quiet at the moment. Equally good is the (so called) "antis" aren't trying to score points whilst the program is down. It's a pretty serious set back that's going to take a very long time to fix properly.
It's a time to wait and see. And take any early announcements with a huge pile of salt - so much money involved, there will be a lot of promises and lots of postings about how well the rest of the program's going.
Wait and see.
It's a time to wait and see. And take any early announcements with a huge pile of salt - so much money involved, there will be a lot of promises and lots of postings about how well the rest of the program's going.
Wait and see.
Also makes the 'you dont need a twin engined aircraft anymore because modern engineering is so advanced!' argument a little awkward.
Equally good is the (so called) "antis" aren't trying to score points whilst the program is down.
Never interrupt your enemy when he is making a mistake. - Napoleon (attrib.)
Never interrupt your enemy when he is making a mistake. - Napoleon (attrib.)
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Never interrupt your enemy when he is making a mistake. - Napoleon (attrib.)
If only...
GK121 - absolutely spot on there. No arguments from me on that. Pratt has a history of making reliable engines...oh hang on..
Quote:
Also makes the 'you dont need a twin engined aircraft anymore because modern engineering is so advanced!' argument a little awkward. It's a slightly different issue in this case. An F-35 powered by two F135 engines would just have double the potential for an engine failure, so paradoxically a single-engined F-35 actually is actually less likely to go tech right now...
Also makes the 'you dont need a twin engined aircraft anymore because modern engineering is so advanced!' argument a little awkward. It's a slightly different issue in this case. An F-35 powered by two F135 engines would just have double the potential for an engine failure, so paradoxically a single-engined F-35 actually is actually less likely to go tech right now...
Do a Hover - it avoids G
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Also makes the 'you dont need a twin engined aircraft anymore because modern engineering is so advanced!' argument a little awkward.
The engineering facts are that if you can fit a single engine that has enough thrust to meet the spec the aircraft will be safer (in respect of engine failure) than a twin design of the same total thrust.
It was appreciating this in the 70s that made the USN change from "our new trainer must have two engines" to "single engine designs are acceptable" and was one of the reasons why the single engine Hawk became the starting point for the T45 Goshawk.
BTW the first Alpha Jet, Tornado and Typhoon total losses all involved double engine failures.
Of course if you need two engines to get the total thrust that you need for the design you have no option but to put up with the various disadvantges that brings.
The fact is that you will have half as many engine failures with a single, other things being equal.
But they are not necessary equal. Engines don't scale geometrically and larger engines are more complex (more blades, for instance). Components such as disks may be more heavily loaded and damage to the airframe more severe. (QF32.)
That's also part of the reason that large engines may have a lower thrust/weight ratio than smaller engines (compare the F414/EJ200 with an F110, not to mention F135). Two engines are shorter (nice fit for a delta) and when you get to a single large engine, arranging all the systems around a hole the size of an L.A. storm drain is no fun at all.
And while some single-engine failures on a twin may be catastrophic (it sounds as though the most recent F135 failure was bad enough to do that), the great majority of power-loss events on a single-engine fighter will result in loss of aircraft.
But they are not necessary equal. Engines don't scale geometrically and larger engines are more complex (more blades, for instance). Components such as disks may be more heavily loaded and damage to the airframe more severe. (QF32.)
That's also part of the reason that large engines may have a lower thrust/weight ratio than smaller engines (compare the F414/EJ200 with an F110, not to mention F135). Two engines are shorter (nice fit for a delta) and when you get to a single large engine, arranging all the systems around a hole the size of an L.A. storm drain is no fun at all.
And while some single-engine failures on a twin may be catastrophic (it sounds as though the most recent F135 failure was bad enough to do that), the great majority of power-loss events on a single-engine fighter will result in loss of aircraft.
Last edited by LowObservable; 12th Aug 2014 at 17:32.
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O/T...
References please.
Wasn't the FIRST Tornado loss @ Manching where the aircraft looped too low?
Ref ASN Aircraft accident 16-APR-1980 Panavia Tornado MRCA 98+05
I remember this because, as part of the transfer from 1940's tech to 1970's tech, the RAF ground school, as part of their flight safety induction for us played the CVR of the crew after they realised it was endex, all the way down. A shocking thing for young Erks to listen to, very upsetting if I'm honest, BUT it rammed the flight safety message home and molded the techs attitudes.
Last edited by glad rag; 12th Aug 2014 at 17:08. Reason: Add picture
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The irony off course is that the F35B (MARINES) is factually a 2-engined (2 propulsion sources) equipped fighter in the most crucial phase of its flight (TO and LANDING both rolling and vertical), ironic even more that it is an added liability iso an extra safety because any failure of one of both power-sources (which are mechanically coupled= extra risk) leads to an immediate catastrophic failure.
The YAK-41 suffered from this shortfall too btw.
Also the notion that 2 engines or more don't provide an extra safety measure is just plain and simple wrong (and I cannot understand why anybody would say differently).
the US DoD, at the end of the millennium, did a widespread statistical study on engine related class-A mishaps and did indeed show a significant elevated risk for single engined aircraft, the F16 being the best performer for single engined fighters was still far behind one of the weaker performing twins like the F14.
That being said, I do think that , under most circumstances, nowadays a single engined fighter, trainer or other single or twin-seater , is a very viable option because of improved technological fidelity.
EDIT,
found a younger chart from 2014 (not as detailed as study mentioned before)
http://www.afsec.af.mil/shared/media...140729-015.pdf
Also both the ISRAELI air force ,and before the USAF (during VIETNAM), found a strong correlation between risk for single engined fighters performing ground support tasks (close air support) and multi engined fighters.
The F104 was very susceptible to ground fire , the F5 and F4 much less so (props are also better btw).
Pierre Sprey's remark concerning the survivability of the F35 against light ground weapons was actually valid.
The YAK-41 suffered from this shortfall too btw.
Also the notion that 2 engines or more don't provide an extra safety measure is just plain and simple wrong (and I cannot understand why anybody would say differently).
the US DoD, at the end of the millennium, did a widespread statistical study on engine related class-A mishaps and did indeed show a significant elevated risk for single engined aircraft, the F16 being the best performer for single engined fighters was still far behind one of the weaker performing twins like the F14.
That being said, I do think that , under most circumstances, nowadays a single engined fighter, trainer or other single or twin-seater , is a very viable option because of improved technological fidelity.
EDIT,
found a younger chart from 2014 (not as detailed as study mentioned before)
http://www.afsec.af.mil/shared/media...140729-015.pdf
Also both the ISRAELI air force ,and before the USAF (during VIETNAM), found a strong correlation between risk for single engined fighters performing ground support tasks (close air support) and multi engined fighters.
The F104 was very susceptible to ground fire , the F5 and F4 much less so (props are also better btw).
Pierre Sprey's remark concerning the survivability of the F35 against light ground weapons was actually valid.
Last edited by kbrockman; 12th Aug 2014 at 18:01. Reason: extra info
Do a Hover - it avoids G
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Sorry chaps
I should have said the first total losses due to technical failure.
I wouldn’t count poor Ludwig’s accident as a specific Tornado one.
As for open source references I don’t have any to hand but I believe they would not be hard to find. The Alpha Jet was in Egypt and the Typhoon of course in Spain.
More importantly, while I am no expert in all the reasons I have heard some very bright people talking about them and they revolve not just on the obvious two engines to fail but on the much more complicated installations involved with a twin when you have to be able to fly the aircraft on either engine (I believe the gearbox that links both engines on a Tornado for example absorbs some 300+ HP) plus the close proximity of the engines to each other where the bad donk can so easily damage the good one. (quite unlike the civvy twin case) .Since a lot of engine failures result from intake conditions a common intake for both engines can obviously lose you both (Spanish Typhoon).
Like I said there are lots of factors and I am sure I have not listed them all here.
In the case of the Harrier single engine installation we decided that the original very complex hydro-mechanical engine fuel control system was the single most likely cause of engine failure so a standby independent manual fuel system was incorporated (in the days before electronics and redundancy was available in that department).
The design of high performance military aircraft is not a simple matter with many compromises involved. The teams involved are not thick either. So those who pick simple holes in whatever issue is being discussed probably say more about themselves than the topic
I should have said the first total losses due to technical failure.
I wouldn’t count poor Ludwig’s accident as a specific Tornado one.
As for open source references I don’t have any to hand but I believe they would not be hard to find. The Alpha Jet was in Egypt and the Typhoon of course in Spain.
More importantly, while I am no expert in all the reasons I have heard some very bright people talking about them and they revolve not just on the obvious two engines to fail but on the much more complicated installations involved with a twin when you have to be able to fly the aircraft on either engine (I believe the gearbox that links both engines on a Tornado for example absorbs some 300+ HP) plus the close proximity of the engines to each other where the bad donk can so easily damage the good one. (quite unlike the civvy twin case) .Since a lot of engine failures result from intake conditions a common intake for both engines can obviously lose you both (Spanish Typhoon).
Like I said there are lots of factors and I am sure I have not listed them all here.
In the case of the Harrier single engine installation we decided that the original very complex hydro-mechanical engine fuel control system was the single most likely cause of engine failure so a standby independent manual fuel system was incorporated (in the days before electronics and redundancy was available in that department).
The design of high performance military aircraft is not a simple matter with many compromises involved. The teams involved are not thick either. So those who pick simple holes in whatever issue is being discussed probably say more about themselves than the topic
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I wouldn’t count poor Ludwig’s accident as a specific Tornado one.
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I believe the gearbox that links both engines on a Tornado for example absorbs some 300+ HP