AlGa wrote:@Coati
Single/twin is perhaps not a problem for a peace time air force. But things change whenever an aircraft is threatened by IR seeking ground fire.
Furthermore, in Canada they have what they call the 'Goose factor': apparently many power losses are caused by birdstrikes. And when you have two air intakes and two engines instead of one, it makes a big difference if the pilot aims to get the airplane back to an airfield.
About politics and F-35, I'm not aware of any particular case ...
Here a nice read about 1 vs 2 engine fighters and the myth that 2 engines are a safety contingency and cause less losses (war and peace time):
And as counter-intuitive as it may sound, single-engined fighters have better combat survivability as well. Most modern Western fighters have engines so close together that any amount of damage taking out one engine is almost certain to take out another as well. Even if a twin-engined aircraft loses a single engine without another one getting taken out, it immediately looses 50% of the thrust and 81% of the performance, making it a sitting duck and easily killed by the opponent. One of reasons for that is large amount of assymetric thrust generated by only one working engine, and designs most likely to suffer loss of only one engine in combat are also ones that have widest engine spacing and thus greatest amount of assymetric thrust and roll inertia. Due to all above factors, twin-engined fighters are more likely to get hit in combat while not being any more likely to survive getting hit.
Twin engined designs do not necessarily have better peacetime survivability either. F-106, despite being single-engined, had 15 losses in first 90.000 hours, compared to 17 for the F-4. In the first 213.000 hours, it had 26 losses, compared to 44 for the F-4. It can be seen that the more complex F-4 had worse loss rate than the F-106 despite having two engines, and while F-106s loss rate improved, F-4s grew worse. Single-engined F-105 also had low peacetime loss rate.
Swedish JAS-39 has a better safety record than the F-18 despite having one engine less – 13% of Canada’s CF-18s have been lost in crashes compared to 2% of Gripens; a loss rate of 0,36% per year versus 0,08% per year for Gripens. Rafale suffered 4 crashes in 64.000 hours, 3 were due to the pilot error. F-16 fleet logged 11 million flight hours by 2004, with 493 losses. Comparing Gripen with Eurofighter Typhoon, Gripen suffered 5 crashes total in 203.000 flight hours. None were related to either engine or aerodynamic configuration of the aircraft: 2 were due to underdeveloped FCS, 2 were due to the pilot error and 1 was due to ejection seat issue. Typhoon suffered 3 crashes total in 240.000 flight hours. One was due to double engine flameout and two due to unexplained reasons. F-22 reached 100.000 flight hours on 11.9.2011., and by that time had 4 losses.
Overall, F-15 had a crash rate of 2,36 per 100.000 hours and F-16 of 4,48 per 100.000 hours. Less than quarter of the F-16 losses were due to the engine failure, with leading cause of losses being FCS issues and human mistake. On the other hand, most F-15s lost have experienced engine fires, meaning that engine-related loss rate is actually higher for the F-15 than for the F-16. F-18 crash rate is 3,6 per 100.000 hours, and Gripen’s is 2,46 per 100.000 hours, compared to 1,25 for Typhoon and 6,25 for Rafale. F-16s safety has improved over time, with cumulative loss rate with 11.000.000 hours being 4,48 losses per 100.000 hours, cumulative loss rate at 12.000.000 hours being 3,55 per 100.000 hours and non-cumulative loss rate at 12.000.000 hours being 1,59 per 100.000 hours. F-22s loss rate is 4 in first 100.000 hours. As already mentioned, however, most losses were not engine-related: engine-related loss rate is 0,00 per 100.000 hours for Gripen and 0,42 per 100.000 hours for Typhoon.
Overall, statistics show that single-role air superiority fighters tend to be safer than contemporary multirole fighters regardless of number of engines (ref. F-106 vs F-4, F-15 vs F-16, Typhoon vs Rafale vs Gripen). And while loss of engine in a single-engined fighter invariably means that the aircraft is lost, engine is not the leading cause of loss (especially today), and lesser reliability of some other systems can make survivability benefits of having a second engine irrelevant.
And while very rare, it is also very possible to land a single-engine fighter with engine out. More common are crashes of twin-engine aircraft due to a single-engine flameout.
https://defenseissues.net/2014/08/09/si ... -fighters/
and
http://bestfighter4canada.blogspot.co.u ... afety.html
Twin-engine aircraft are built as twin-engined aircraft. Both turbines work together to propel the aircraft as a single propulsion system. One engine does not work as a "spare" to the other. A catastrophic failure in one would result in a near-instantaneous sudden loss of power and an extremely ill-handling airplane. The malfunctioning engine would act as "dead weight", contributing to extra drag while adding power to the opposite engine to compensate would result in the aircraft rotating on its yaw axis.
On top of all this, there is the underlying cause of the engine malfunction to worry about. A fire or structural failure could easily spread to the remaining engine. As could a loss in fuel pressure. In some cases, the loss of one engine is simply a precursor to the second engine following suit
Indeed it has nothing to do with safety to put two engines in an aircraft (certainly not nowadays) but with thrust requirements, weight, payload etc. As I mentioned earlier I remember the same discussion being mentioned when I worked for the MoD about some people claiming the supposed unsafety of a single engine F-16. So a study was performed by an institute and back then the outcome was that one or two engines is not affecting flight safety (and as you saw combat survivability as well). The USN had the F-8 as its air defense fighter, A-4 and A-7 as its attack aircraft, RCAF had its F-104 and F-86, RAF has the F-35, has hunters etc etc. Especially about the claim I read many times that the USN would never allow single engine jets to operate from their carriers...quite a few of them were single engine aircraft (if you descent further in the past...).