F-35 Cancelled, then what ?
... is more reliable than the f-15 with 2 engines ...
So are we talking engines or aircraft?
No intention on mixing up with your interesting discussion, but allow me a comment from the pilots side.
As a pilot you do not care about the statistics of the engine system itself, but about the statistics in the specific airframe.
And there a double engine layout has a definite advantage over an single engine layout, in peacetime and when bad guys are starting to shoot at you.
See f.e. the following graphs:
Two-engine aircraft
Single engine aircraft
The J79 was contributing to 60 times more engine related class a mishaps in single engine aircraft (F104) than in dual engine aircraft (F4)
As the engines got more reliable over the years, that advantage got less important, but itīs still there. If you loose one engine, the other one can save the day.
As a pilot you do not care about the statistics of the engine system itself, but about the statistics in the specific airframe.
And there a double engine layout has a definite advantage over an single engine layout, in peacetime and when bad guys are starting to shoot at you.
See f.e. the following graphs:
Two-engine aircraft
Single engine aircraft
The J79 was contributing to 60 times more engine related class a mishaps in single engine aircraft (F104) than in dual engine aircraft (F4)
As the engines got more reliable over the years, that advantage got less important, but itīs still there. If you loose one engine, the other one can save the day.
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F110-GE-132 is the latest f-16 engine and about 10 years service and I don't recall the total units flying
edit... RetiredF4, thanks for putting up these charts, it jogged my memory, it was the F-16 F100-PW-229 with 299,368 EFH that was used in the one engine example great debate a few years ago and unless one of the 229 or 132 have engine crashed recently, it has a clean record
ORAC, also it would help if you wern't abusive especially when you are wrong and used an early f-16 engine
edit... RetiredF4, thanks for putting up these charts, it jogged my memory, it was the F-16 F100-PW-229 with 299,368 EFH that was used in the one engine example great debate a few years ago and unless one of the 229 or 132 have engine crashed recently, it has a clean record
ORAC, also it would help if you wern't abusive especially when you are wrong and used an early f-16 engine
Last edited by JSFfan; 9th Dec 2012 at 15:04.
JSFfan, I really wish you had taken all the hints. Now I wish you would just leave the forum.
Didn't think it was possible to annoy ORAC, but you managed it. Pat yourself on the back on find some other forum to bother.
Didn't think it was possible to annoy ORAC, but you managed it. Pat yourself on the back on find some other forum to bother.
Two engines. Greater probability of a technical, single engine failure. Some, but not huge, difference in probabilites of single and total power failure through FOD, birdstrike, combat damage, etc - although (again) double engine failure much less likely. Probaility of total power loss leading to loss of airframe, significantly less.
Single engine. Yep, smaller probability of a single engine failure, but when it happens the consequences are in a different league.
Why build single engined aircraft? Cost, weight, size. Fine for trainers or if you want larger numbers of airframes, but if you're building the country's new "do everything" fighter-bomber, logic dictates that two are better than one. It offers greater survivability and payload, although as soon as you go to vertical flying, you've already accepted that payload isn't near the top of your wishlist.
Single engine. Yep, smaller probability of a single engine failure, but when it happens the consequences are in a different league.
Why build single engined aircraft? Cost, weight, size. Fine for trainers or if you want larger numbers of airframes, but if you're building the country's new "do everything" fighter-bomber, logic dictates that two are better than one. It offers greater survivability and payload, although as soon as you go to vertical flying, you've already accepted that payload isn't near the top of your wishlist.
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Courtney - indeed, there's lots of cold water between Leuchars and 60N on the meridian. Just looking at the map made me shiver - and I never needed to fly the intercepts, I was always pleased that there were two RB199s for the crews.
JSFfan: Suggest you bin your military career aspirations and instead join either the JPO or apprentice yourself to some "leading" military thinkers - Air Power Australia or Lewis Page should be suitably impressed by your paranoid illogic. And feel free to apologise the ORAC, JTO et al on your way out, there's a good chap.
S41
JSFfan: Suggest you bin your military career aspirations and instead join either the JPO or apprentice yourself to some "leading" military thinkers - Air Power Australia or Lewis Page should be suitably impressed by your paranoid illogic. And feel free to apologise the ORAC, JTO et al on your way out, there's a good chap.
S41
Do a Hover - it avoids G
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Considering whether one or two engines is safer today not is not a simple common sense issue.
My memory may be letting me down but I seem to recall that the first total losses of a Tornado, Alphajet and Erofighter were all total power faiulures.
In my experience the most likely cause of engine failure in a single engine aircraft is an engine control system problem rather than the mechanical bits letting go. Which is why we fitted an additional emergency Manual Fuel System in later Harriers.
When the USN specified a twin engine aircraft for their new (now current) trainer (way back) a single engine solution based on the Hawk was clearly non-compliant. Kingston submiited the case as to why in the modern world and for this job one engine was safer when flying from a USN carrier and were able to convince the USN by engineering arguement that this was indeed so. So the single engined Goshawk was chosen over a real twin (Alphajet based) and several US industry based paper twins.
My memory may be letting me down but I seem to recall that the first total losses of a Tornado, Alphajet and Erofighter were all total power faiulures.
In my experience the most likely cause of engine failure in a single engine aircraft is an engine control system problem rather than the mechanical bits letting go. Which is why we fitted an additional emergency Manual Fuel System in later Harriers.
When the USN specified a twin engine aircraft for their new (now current) trainer (way back) a single engine solution based on the Hawk was clearly non-compliant. Kingston submiited the case as to why in the modern world and for this job one engine was safer when flying from a USN carrier and were able to convince the USN by engineering arguement that this was indeed so. So the single engined Goshawk was chosen over a real twin (Alphajet based) and several US industry based paper twins.
Last edited by John Farley; 9th Dec 2012 at 17:37.
Do a Hover - it avoids G
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S41
Just to let you know I have just ammended my post to read total power loss rather then double engine failure. Both may be the same to the pilot but the associated engineering causes can of course be very different.
JF
Just to let you know I have just ammended my post to read total power loss rather then double engine failure. Both may be the same to the pilot but the associated engineering causes can of course be very different.
JF
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Stats can prove whatever you want 
I seem to recall that the reason that Harriers weren't allowed to fly over London for fly pasts in recent years was that the risk of engine failure was too high given the chances of landing in a heavily populated area. Not helped by Harriers not gliding very well (JF feel free to comment as appropriate!) No such issues of course for Hawks.
Getting the lift fan/swivel nozzle mechanism to work with two engines would have been interesting.
To keep things common that probably drove the single engine design across all 3 variants.
LO - With partner nations involved at the Programme Office and the Development Test sites feeding back info to their respective governments at least they don't have to rely on media reports or LM press releases to make decisions on. (Whether they listen is another question!)
I seem to recall that the reason that Harriers weren't allowed to fly over London for fly pasts in recent years was that the risk of engine failure was too high given the chances of landing in a heavily populated area. Not helped by Harriers not gliding very well (JF feel free to comment as appropriate!) No such issues of course for Hawks.
Getting the lift fan/swivel nozzle mechanism to work with two engines would have been interesting.
To keep things common that probably drove the single engine design across all 3 variants. LO - With partner nations involved at the Programme Office and the Development Test sites feeding back info to their respective governments at least they don't have to rely on media reports or LM press releases to make decisions on. (Whether they listen is another question!)
Apart from a brief interlude flying the Jaguar for a year - a twin engined aircraft with the total thrust of a single engined aircraft!! - I spent my military career flying on one engine - Trainers various, Hunter, Harrier, A-4, A-7, F-16 - and I never had an engine failure!!
Lucky? - Maybe.
But let's get the onevtwovmany argument in perspective!!
Lucky? - Maybe.
But let's get the onevtwovmany argument in perspective!!
AFAIR from reading, there has not been an engine crash with the later engine which i recall is the f110?
this concern is unfounded statistically
glad rag, I don't know what better stats you want for the f-16/f110? than it hasn't had a engine crash yet and is more reliable than the f-15 with 2 engines as I recall
These are direct quotes of yours mate. You need to be more specific, because by not being specific you are looking pretty silly And probably stop with the AFAIR stuff aswell, because it has now been proven 2/2 that your recall has been at worst dead wrong, and at best non specific and vague.
Gladrag, Nice video. I'm sure what a hand cued IR video of a Raptor taken against a blue sky background at a slant range of probably no more than a mile is trying to prove, or better yet maybe you could show how a non LO aircraft in the same situation as LO has a lower risk of being hit?
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slant range of probably no more than a mile
non LO aircraft in the same situation as LO has a lower risk of being hit
By the way, a little extra on the 1v2 engine argument...
If you look at the T/W ratio of jet engines over the years, you will get the impression that there is a square-cube law at work in that the biggest military jet engines have lower T/Ws than smaller ones. I think the best of the F110/F100 group manage about 8, but the F414/EJ200 are at 9-9.2 and neither has been through an uprate.
I have also seen it argued (I think in discussion of early 1v2 arguments on Typhoon) that two engines are shorter and may pack in there better.
As for safety, it seems logical that singles are subject to an aircraft-loss mode (loss of power internal to one engine) that does not affect twins... and I have yet to see anyone advocate single-engine airliners.
If you look at the T/W ratio of jet engines over the years, you will get the impression that there is a square-cube law at work in that the biggest military jet engines have lower T/Ws than smaller ones. I think the best of the F110/F100 group manage about 8, but the F414/EJ200 are at 9-9.2 and neither has been through an uprate.
I have also seen it argued (I think in discussion of early 1v2 arguments on Typhoon) that two engines are shorter and may pack in there better.
As for safety, it seems logical that singles are subject to an aircraft-loss mode (loss of power internal to one engine) that does not affect twins... and I have yet to see anyone advocate single-engine airliners.