Hi Smut,
>Indeed, while it was accepted that a jet engine was less survivable than a radial engine, the greater speed of the jet engined powered aircraft was seen as a way to offset this.
That's a good starting point if you mean to convince me. What are the details, and what are your sources?
>I thought this thread was about the 1944-45 era Me-262 and its engines, not aircraft that came 20 years later.
Currently, there are two statements under discussion:
1.) There was no principal difference in combat survivability between the Jumo 004B and other jet engines.
2.) Jet engines generally have a greater combat survivability than piston engines.
>I'm afraid I should tell you that, as a Reliability and Maintainability Senior Engineering Technician, I am quite familar with "basic statistic knowledge".
Afraid? No reason to, I think it's great! I'm looking forward to new contributions with a high level of professionalism then :-)
>There are many documented cases during WW2 where badly damaged radial engines continued to operate (although usually at less power) for extended periods of time. This is not a "limited sample".
Let me explain the concept of an arbitrarily limited sample again: Looking at engines that survived in spite of great damage and failing to look at damaged engines of aircraft that did not come back means that your sample is arbitrarily limited.
A numeric example: 1000 engines get hit in combat, 900 fail, 100 survive so that the aircraft comes back with heavy damage.
Looking at the engines that came back, you can analyze any level of damage just to arrive at the conclusion that 100% of the analyzed engines survived that damage.
Even better, if you find 50 engines with shot-out cylinders among the survivors, you can conclude that 100% of the analyzed engines survived even very heavy damage.
However, the interesting data is that about the 900 engines that were hit and didn't come back. For our example engine, you'd see that only 10% of the damaged engines survived.
An analysis of the 900 destroyed engines, if it had been possible, might have yielded the result that 450 of them had been destroyed by "shooting out" single cylinders. Again, we'd see that despite the high number of survivors for this level of damage, the chances of the engine actually surviving damage of this magnitude were only 10%.
So, there's really nothing to be gained from digging out documented examples of heavily-damaged engines that brought their aircraft back home as long as the number of engines damaged to the same degree that failed remains unknown.
As I already pointed out, actual loss ratios per missions would tell us much more about combat survivability than any number of cases of engines surviving battle damage. These ratios seem to be hard to get, and they still wouldn't tell us everything as they'd describe the survivability for the entire weapons system under specific threat conditions, but that's better than pure speculation anytime.
>How many of those 400 people were on jet powered aircraft, hmmm? You seem to have ignored that little factiod.
My point was the probability of the event actually occurring: Literally millions of flights were necessary until 400 people were killed by birdstrikes. Though the catastrophical consequences of bird strikes on jet engines are well known and often described, in reality bird strikes with catastropical consequences have a very low probability.
(To answer your question, I'd speculate that the majority of the bird strike victims were aboard jet aircraft. However, since piston-engined general aviation aircraft are much more numerous and spend a lot of time at low altitudes where they are more likely to encounter birds, I might be wrong. The main killing mechanism for GA aircraft could be injury to the pilot, not damage to the engine. However, I've got to emphasize that without further data, this is all pure speculation.)
Regards,
Henning (HoHun)
