Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Hristo on July 08, 2002, 12:36:22 AM
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What is your experience regarding 262's durability ?
IMO, it doesn't take much to blow up or lose parts. AFAIK, it was built using quite many steel components instead of aluminium.
Or is it flying tanks of gas syndrome ?
Any thoughts ?
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Me262 had armored front window glass and an armored seat back, so its more likely flying gas tank...
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In my experience, the 262 is as fragile as a small paper bag. One ping will take something off.
Yesterday I was in a 262 and a p51 got on my 6 about D 1.0 out. Naturally he was spraying like a madman, and I was constantly moving around to avoid being an easy target. I heard one ping, and I cant have been hit by that many bullets since I must have flown through his spray-stream of bullets. BAM, engine 1 & 2 oil gone. I could almost hear the P51 jock wet himself with excitement since I was now trailing black smoke from both engines. I managed to get away and land on one engine though (apparently the engines leak oil att different rates).
SO here is a big to the bish P51D pilot who was over A78 yesterday and pinged a knight 262. Better luck next time. :)
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You did bad. In 262 it is very easy to deny a shot to just about anybody.
j/k, of course. The ability to stay untouchable should not be an arbitrary factor to the 262 durability.
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"Apparently the engines leak oil att different rates."[/b]
This is not specific about the 262, but when you get an oil leak it is random from time to time, at what rate you are loosing oil. Find the oil pressure gauge and see how quickly it drops. Sometimes you can go on for several minutes, other times it's only a matter of seconds.
__________________
Ltn. Snefens
Lentolaivue 34 (http://www.muodos.fi/LLv34)
My AH homepage (http://home14.inet.tele.dk/snefens/index2.htm)
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AFAIK, the 262 was fairly vulnerable to gunfire. The engines were its Achilles Heel. We are talking about a piece of cutting edge equipment that was using rather embryonic engines made when there was a lack of proper resources available. If a bird getting sucked into a modern jet engine can cause catastrophic damage, what do you think a couple .50 cal bullets are going to do to the early jet engines of the mid 40's?
As far as other parts of the aircraft, I couldn't begin to say whether it was more or less likely to lose parts if hit.
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I think that the p51 was lucky. If im flyin a 262 and theres another plane on my 6 i just nose down and hit 500. have a few drinks then turn and stray his tail with some good oold 30mm rounds. and remember I only need a couple o shots.
HAHAHAHAHAHAHAHAHA
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Hi Hristo,
>AFAIK, it was built using quite many steel components instead of aluminium.
Good point: While the Me 109 consisted of 95% light alloys, the Me 262 had the precentage reduced to just 55%.
The Me 262 was well armoured, too: It was protected by 196 kg (432 lbs) of armour plate. For comparison: The P-38 - similar in being a twin-engined single-seat fighter - carried 330 lbs of armour.
Jet engines by design were much more resistant to battle damage than piston engines since they lacked extensive radiator and oil cooling systems that were the achilles heels of piston engines. They ran without the auxiliary systems (like the ignition gear) that were indispensable for piston engines, and the jet engine itself consisted of very few moving parts that were difficult to damage critically.
The Korean War demonstrated the high durability of jets very well. Though the USAF fighters' heavy machine guns were considerably improved over the WW2 versions, and though they had a ballistically ideal centre-line battery, the MiGs were capable of absorbing much more damage than the WW2 piston fighters could and still return home. As a consequence, the USAF battle-tested 20 mm cannon (Project GUNVAL) and generally adopted them for future fighters.
In short: The Me 262 had a durable structure with a large percentage of steel components, it was well armoured, and its jet engines were able to withstand battle damage better than piston engines could. On top of that, it had two of them :-)
Regards,
Henning (HoHun)
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It is a 'gameplay concession'.. I asked either Superfly or Hitech about why the wings and engines get damaged so easily, they said they were modelled that way on purpose.
I can only guess it is because the engine unreliability isn't modelled, so they felt they had to give it some sort of Achille's Heel. (other than the 200 point price tag I mean).
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The jet engines may have been "durable", but moreso than the Pratt & Whitney? No way. EDIT: In fact, the jet engines used in WWII were not more durable than anything... except maybe balsa wood. MiG and F86 jet engines differed greatly from those of the Arado and 262.
The turbines were easily destroyed on the 262, them lil blades fell off a good deal resulting in catastrophic engine failure.
It was the only spot on the 262 to aim for, most pilots reported hitting the engines with a quick burst, and they would immediately begin smoking and/or begin to burn.
-SW
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Originally posted by Mathman
If a bird getting sucked into a modern jet engine can cause catastrophic damage, what do you think a couple .50 cal bullets are going to do to the early jet engines of the mid 40's?
Hmm... how couple of 50cal bullets and bird relate to eatchother? I cant see any connection.
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Originally posted by Urchin
It is a 'gameplay concession'.. I asked either Superfly or Hitech about why the wings and engines get damaged so easily, they said they were modelled that way on purpose.
I can only guess it is because the engine unreliability isn't modelled, so they felt they had to give it some sort of Achille's Heel. (other than the 200 point price tag I mean).
Why don't they model planes as realistically as they can???
How about unrealiability in other planes, cannons etc? Is there also some "compensation"?? I fail to see how more unrealism compensates unrealism.
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Hi Akswulfe,
>The jet engines may have been "durable", but moreso than the Pratt & Whitney? No way.
Thanks for contributing another opinion. If you'd only spiced it up with a tiny little bit of fact ... but it's not too late for that yet.
Regards,
Henning (HoHun)
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Originally posted by Hristo
You did bad. In 262 it is very easy to deny a shot to just about anybody.
j/k, of course. The ability to stay untouchable should not be an arbitrary factor to the 262 durability.
Full story on how the P51 got my engines here (http://www.hitechcreations.com/forums/showthread.php?s=&threadid=58257)
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I did, or did you not understand those other characters I typed were words?
The turbines were easily destroyed on the 262, them lil blades fell off a good deal resulting in catastrophic engine failure.
It was the only spot on the 262 to aim for, most pilots reported hitting the engines with a quick burst, and they would immediately begin smoking and/or begin to burn.
-SW
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Hi Akswulfe,
>I did, or did you not understand those other characters I typed were words?
Did you really expect to be taken seriously after the "balsa wood" comment?
>The turbines were easily destroyed on the 262, them lil blades fell off a good deal resulting in catastrophic engine failure.
Turbine blades were lost due to engine faults, mostly caused by overspeeding due to failure of the engine controls. At 9000 rpm, the blades were perfectly safe, but at 11000 rpm things became dicey. Hitting a jet engine in a way to make it lose a turbine blade is highly difficult since the root of the blades are the innermost parts except for the turbine axis itself. It's much more likely that you'd manage to hit the actual turbine blade, causing some vibration that would force the pilot to throttle back the engine.
>It was the only spot on the 262 to aim for, most pilots reported hitting the engines with a quick burst, and they would immediately begin smoking and/or begin to burn.
Superficial damage to a jet engine's casing would cause the turbine gases which are under high pressure to stream out of the leak, but this would have have little relevance for the integrity or even the power output of the engine itself.
You'd have a much better reason to worry if the same amount of smoke would be coming from one of your Pratt & Whitney engines ...
Regards,
Henning (HoHun)
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I guess 262 engines simply falling apart on the runway before take off was the result of the engine being so durable it actually destroys itself.
The Jumo engines were by no means durable, reliable, or going to take much damage.
F86, and MiG-15 engines... sure, but those are like 6 generations later (in engine terms)....
Pratty & Whittney engines could still run after losing 1 or more cylinders. The "durable" Jumo engines would eat themselves apart if they lost a blade.
-SW
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The 262s engines had a service life of 10 to 20 hours. Also, the 262s engines were in a bad position, as they hanged below the aircraft.
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Hi Akswulfe,
>The Jumo engines were by no means durable, reliable, or going to take much damage.
You're confusing several things here. These are
- projected engine life
- engine reliability against random failures
- resistance to battle damage
Projected engine life of the Jumo engines was low. This was not much of a problem - they were being turned out at a high rate so replacement engines were available. (Fuel was a greater problem than engines.)
Engine reliability against random failures was initially low, but rose while the teething troubles were cured. The overall level remained inadquate, but since most of the early jet aircraft were twins, this wasn't a serious operational problem either.
Resistance to battle damage was unconnected to projected engine life or random failure probability. The poor quality of your high temperature alloys matter little if someone is shooting holes in your engine casing.
However, the Jumo engines had just the same undeniable advantages over piston engines as later generation engines: Few moving parts, few and well-protected critical components, no extensive glycol or oil cooling system, no critical external sytems like the piston engine's indispensable ignition system.
As the end result, a Jumo jet engine - like any jet engine - was quite a bit tougher than any piston engine. And the Me 262 actually had two of them for even greater survivability.
Regards,
Henning (HoHun)
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Everything that I have read indicates that the engines themselves, comparing the Jumo 004Bs to Merlins/Allisons/R-2800s/DB605s/Sakae 21s, were much, much softer targets. A .303 round is unlikely to do any damage if it strikes the engine block of a piston engine, however that same .303 round will cause catastrophic failure if it hits the Jumo 004B.
Remember, we are talking about the durability of the engine itself, not the engine + support systems.
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Hi Karnak,
>Everything that I have read indicates that the engines themselves, comparing the Jumo 004Bs to Merlins/Allisons/R-2800s/DB605s/Sakae 21s, were much, much softer targets.
How about posting some quotes then? I'd appreciate something more substantial than the "I hit them and they smoked" variety though.
>A .303 round is unlikely to do any damage if it strikes the engine block of a piston engine, however that same .303 round will cause catastrophic failure if it hits the Jumo 004B.
By which mechanism? A 7.7 mm round probably would be deflected by the engine casing anyway, but even if it penetrated, what could it do?
>Remember, we are talking about the durability of the engine itself, not the engine + support systems.
Remember that if you pierce the Mustang's radiator, hole the P-47's oil reservoir or disable a Spitfire's ignition system, the engine is just as dead as if you'd split the crankshaft.
It's a recognized fact that jet engines in general are a lot more resistant against battle damage, and the only question that's worth debating is if the Jumo 004 had any kind of untypical vulnerability to enemy fire that made it less resistant.
So far, I've not seen anything that hints in that direction.
Regards,
Henning (HoHun)
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A compressor blade falling off while spinning at a few thousand RPMS is unhealthy for a jet engine. (To put it mildly) Un-like a piston engine, a jet will have a tendancy to rip itself apart if something breaks off.
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(http://www.soton.ac.uk/~genesis/Pictures/Germany/Jumo4__4.gif)
EDIT: here's a better photo
(http://www.warbirdsresourcegroup.org/LRG/images/lrg0727.jpg)
You are telling me those compressor blades are more protected than an engine block?
The Jumo004 is one of the most compact engines, because they had to fit slung underneath a wing, where they are extremely vulnerable.
It may have less vulnerable systems than a piston engine, but the engine itself is vulnerable and would be easy to damage with .50 caliber MGs.
-SW
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Yes 50 cals are l337 tank busters too.
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In the end, a return to the standard rear attack was employed by the jet pilots. With the speed of the Me 262 , they could quickly overtake the bombers to get in close and fire their cannon and quickly dive away from the bomber's guns. Of course they would have to withstand the hail of fire from the bombers rear gun emplacements, something that the lightly armored and somewhat delicate Me 262 did not do well. In fact Steinhoff himself was of the opinion that the jets should be employed against the escorting fighters. The bombers could then be attacked by conventional prop fighters.
I managed to find this material here: http://www.luftwaffe-experten.com/aircraft/day/me262_text.html ,though it lacks detail. Couldn't find much in the way of battle damage, pro or con, for the Jumo 004. I have heard, anecdotally, that the large amount of fuel carried was a vulnerability.
I have also read accounts from Korea where pilots like Gabreski stated that the jets were hard to bring down. I could see the relatively small critical area of the compressor as helping make it harder to kill, but one .50 through the compressor would finish it quickly. Perhaps the Jumos were more exposed slung under the wings than an engine buried in the fuselage of a Mig-15, much like the exposed radiators on the P-51, Spit, Me-109 vs. the chin radiator on the P-40. Just a thought.
Charon
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Having seen first hand what a small steel bolt no larger than a 30cal bullet can do to a modern jet engine, I have no problem understanding how even a single armour-piercing 50cal round would be extremely hazardous to an engine's health.
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never mind a small steel bolt - have you seen what a frozen chicken can do to one?
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well my grate grandfather was in WWII he was just a infatry man but he went though d-day, battle of the bulge, and he was near the invasion of italy.....
he told me this story before.......... he and another private had been walking to scout out the area ahead and found a small air feild..........what was there but 5 262's on a small hidden air strip he ran back to where the fighting had just ended reported it to his sargent...........but as he was gettin toward the first trench he could hear one taking off......... he jumped in the trench grabed a light machine gun pointed it upwards where it would apear and shot at the 262 as it came over a clearing over head " i had only time to fire about 2-3 shots at the damn thing. i saw sparks fly off the undernigheth of the right eng. next thing i know that eng explodes..... then the cockpit burts wide open engulfing the left wing the whole flaming wreck comes down about 400 yrds behind me..........." he proceded to tell the sargent in charge...... they got to the air field and before they could capture it .............the germans started to fire back cuz they had spoted them .........the whole group ducked and fired back......................... ...eventually(skiping fighting part) destroying the 4 262's left and capturing what was left of the airfeild
note i edited a ton of that......... i really don't feel like typing a 5-6 page story right now just telling u the part about the 262's
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5 kills - that scouting party is an 'ace' - not bad for guys would couldn't get into flight school
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he didn't want to fly.......... he said he'd rather "die before i trust something that i can't work on by myself"
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HoHun,
There are numerous sources that refer to the frailty of the Jumo 004.
I was lucky enough over the past 20 years to develop a friendship with a Battle of Britain vet and Supermarine test pilot by the name of Clive Gosling.
His second operational tour was with 616 squadron when they converted to Meteors in 44. In May of 45 he and his CO went to Fassburg to get a couple of 262s and fly them back to Lubeck. One of the things emphasized to him was the frailty of the engines. He was briefed by a German pilot prior to his flight. Engine life was less then 25 hours and the chance of in flight fires was high. In fact when starting up the 262 with the help of a German ground crew, one of the engines did catch fire. Standard procedure was for the ground crew to douse the engine with a fire extinguisher before trying again. He got it going and flew it back to Lubeck, checking it out along the way.
He described its take off roll as longer then a Meteor. Single engine flying speed was about 180. At high speed he said it 'snaked' like a Meteor, but in general felt 'solid'.
And of course it had a weak nose gear as his CO found out on landing on Lubeck when he collapsed the nose gear.
I can type up the text of the letter he wrote me way back when if you want the actual word for word on the flight. It's a four page typed letter from the mid 80s.
Or if you come across Hugh Morgan's Me262 Stormbird Rising, there is a shorter version from Mr. Gosling in that book.
Dan
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Hi Guppy,
>There are numerous sources that refer to the frailty of the Jumo 004.
You post is appreciated, but again, it aims at the reliability problems during normal flight operations, not at its ability to withstand battle damage. Note that the Allies had worse problems with that than the Germans since often, the planes' records were destroyed so that they had no way of knowing whether a Me 262 had fresh engines or whether it was grounded for overhaul. (Eric Brown's "Wings of the Luftwaffe" is quite interesting in that respect.)
Regards,
Henning (HoHun)
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Hi Chunder,
>Having seen first hand what a small steel bolt no larger than a 30cal bullet can do to a modern jet engine, I have no problem understanding how even a single armour-piercing 50cal round would be extremely hazardous to an engine's health.
On the other hand, with some background in jet engines, you're probably aware that they are recognized to be more survivable than piston engines? The question is not what could happen, but what is going to happen with which probability - and that's were jet engines win.
Regards,
Henning (HoHun)
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Hi Charon,
>In fact Steinhoff himself was of the opinion that the jets should be employed against the escorting fighters. The bombers could then be attacked by conventional prop fighters.
There was a good tactical reason for this: The propeller-driven fighters were quite capable of taking on the bombers, but only the Me 262 had the performance to tackle vastly superior numbers of escort fighters with some chance of success. Calling the Me 262 "delicate" in that context sounds a lot like after-the-fact rationalization of Steinhoff's comment.
Regards,
Henning (HoHun)
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Hi Akswulfe,
>You are telling me those compressor blades are more protected than an engine block?
I'm telling you that it's more difficult to kill a Jumo 004 than a contemporary piston engine.
It's a recognized fact that generally jet engines are more battle resistant than piston engines. The Jumo pictures you posted show very nicely that it had a very modern axial compressor of the kind that has become standard decades ago. I'd appreciate it if you'd decide whether you don't believe in the jet engine's inherent superiority when it comes to battle resistance, of whether you can find any special weakness of the Jumo 004 that makes it more damage-vulnerable than the jets that were patterned after it.
>The Jumo004 is one of the most compact engines, because they had to fit slung underneath a wing
The Jumo 004 appears to be one of the "most compact engines" because it's an axial-flow turbojet. That's the layout that quickly prevailed over the radial-flow turbojets initially favoured by the Allies. It did not have to fit slung underneath the wing, as Willy Messerschmitt himself favoured a wing-integral installation as realized by the Gloster Meteor until the small dimensions of the Jumo 004 were ascertained.
Regards,
Henning (HoHun)
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Engine performance, in Aces High, does not degrade with damage. This is contrary to the *real* physical world, but is most likely a gameplay issue. I have seen a Lear 35 engine ingest a 3mm screw and the result was awful. One .50 caliber bullet would have a greater *impact*, I'm sure. :)
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Jet engines, during the Korean war and up to today, may be able to take more damage and keep on ticking than piston engines... but then again, inline engines were able to take more damage in WWII than they could in WWI.
The fact that Germany had to use sub-standard materials to put the engine together shows why the engine had such a short life before having to be overhauled. Which should tell you, that if it's so prone to failures.... certainly a .50 cal slug won't be shrugged off lightly.
All it needed was to be hit forward of the compressor blades, and a .50 cal slug would get sucked into them. At the very least, debri would be sucked into the compressor blades... and that's the end of the story for that engine.
Before you mentioned something about the F86 and MiG-15... you are right, they had some very good engines that were very durable... Jet technology was brand spankin' new in WWII, which would explain the random failures of all jet engines and the relatively short life they had. How many hours of life did the jet engines of the Korean war last? A good more than 20, and this all relates back to durability... sorry, but you keep saying there's a difference between taking damage and engine life... I beg to differ when the engine is capable of destroying itself well before the engine life expectency is up.
-SW
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The records on the 262 in question are fairly clear. It was flown along with four other surviving 262s from Zatec to Fassburg by Lt. Dorn of 3/JG7 on May 8, 1945 It was Yellow 17, Wk.Nm 500210.
The German pilot who briefed Gosling before his flight and mentioned the engine concerns was Hans Frohlich of 2/KG(J)51. He had flown one of the other 262s from Zatec to Fassburg. Those five were the last operational 262s that operated against the Soviets prior to the capitulation. They were flown West for obvious reasons.
The frailty of the engines would clearly be a hinderance in combat. Kinda like the problems facing the 8th AF P38 pilots over Europe.
Was it not a failed engine that cost Walter Nowotney his life in a 262?
You mentioned Eric Brown's book. In his Viewed from the cockpit series that was printed in Air Enthusiast in the early 70s he mentions Messerschmitt Research Test Pilot Gerd Von Lindner as the person who filled him in on flying the 262. He also mentions Von Lindner's 'mistrust' of the Jumo 004 engines.
If you are going to play it out within the game, the chance of an engine failing or the nose gear collapsing on a 262 should probably be part of the deal. The ability of the engine to sustain damaged doesn't seem to me a seperate issue if the thing is apt to give out on its own anyway.
Using the comparison of the reliabilty of the F86 and Mig 15 engines in Korea doesn't fit in this case as well. There was a lot of time between the wars to get the reliabilty up on those engines, not the same as the wartime demands placed on the folks trying to get the 262 into action.
Dan
Originally posted by HoHun
Hi Guppy,
>There are numerous sources that refer to the frailty of the Jumo 004.
You post is appreciated, but again, it aims at the reliability problems during normal flight operations, not at its ability to withstand battle damage. Note that the Allies had worse problems with that than the Germans since often, the planes' records were destroyed so that they had no way of knowing whether a Me 262 had fresh engines or whether it was grounded for overhaul. (Eric Brown's "Wings of the Luftwaffe" is quite interesting in that respect.)
Regards,
Henning (HoHun)
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Hi Guppy,
>The records on the 262 in question are fairly clear.
What I meant is just that the maintainance records for German planes often were destroyed before the capitulation so that British pilots couldn't judge the maintenance status of their prizes.
>The frailty of the engines would clearly be a hinderance in combat. Kinda like the problems facing the 8th AF P38 pilots over Europe.
I agree. But on the other hand, noone would call the Allison vulnerable to battle damage just because the USAAF had so many engine failures with the type.
>Was it not a failed engine that cost Walter Nowotney his life in a 262?
The cause of Nowotny's death was never finally resolved. Ethell and Price speculate that he was shot down by German AAA while being chased by two P-51s.
>Using the comparison of the reliabilty of the F86 and Mig 15 engines in Korea doesn't fit in this case as well. There was a lot of time between the wars to get the reliabilty up on those engines, not the same as the wartime demands placed on the folks trying to get the 262 into action.
The superiority of the jet engine to withstand battle damage is rooted in its operating principle. That's why Korea (actually, all jet combat experience) is a valid point of reference for WW2.
Battle damage has nothing to do with reliability against random failures, which is determined by production and materials quality. The Jumo 004 certainly was poor in that regard, but as the example of the P-38's turbo-supercharged Allison shows, it doesn't say anything about vulnerability against enemy fire.
Regards,
Henning (HoHun)
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Hi Akswulfe,
>Jet technology was brand spankin' new in WWII, which would explain the random failures of all jet engines and the relatively short life they had.
There's no reason to speculate about the reason for the short life of German WW2 jet turbines: They were designed to be short-lived.
The original Jumo 004A engines in fact were long-lived - but they used scarce resources that weren't available for mass production, so the Jumo 004B was conceived to achieve the same power on more readily available materials.
>Which should tell you, that if it's so prone to failures.... certainly a .50 cal slug won't be shrugged off lightly.
With regard to its mechanical properties, the alloy of the turbine blades was very close to that used in the long-lived (and reliable) prototypes. Naturally: This had been the design goal.
If the blades hadn't withstood the stress, the Jumo 004B wouldn't have delivered the power. The downside was that the blades were subject to long-term deformation - but I'd not count a projectile impact as a long-term effect.
In short, there's no reason to assume the Jumo 004B was any more vulnerable to enemy fire than any other jet engine.
>All it needed was to be hit forward of the compressor blades, and a .50 cal slug would get sucked into them.
That's true for any jet engine, and still they are very hard to kill.
Regards,
Henning (HoHun)
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Originally posted by NOD2000
he didn't want to fly.......... he said he'd rather "die before i trust something that i can't work on by myself"
no offense intended, just some friendly needling
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I saw on the history chan, it was an old ww2 german pilot talking about the 262.
one of the things i remember was him saying a simple powering down and quick powering up of the throtel would exsplode the engines..because they were to finiky.
And this was true...imagine dumping a crap load of fule into an empty chanmber..a highly flamable liqued..boom.
unlike a piston engi if you did that it would maby sputer a quick second..but them instantly get upto speed.
hell the f-86 sabre had problems like this also.
Also guys its for game play..that p-51 pilot as you put it was LUCKY to get a shot..and you wanna know why? its cause you were goin' fregin' 500mph...so for game play sakes the 262 HAD to be made weak..because if it was THAT strong..we would never down one unless the pilot flew stupidly into a hail of gun fire..and most head to head servers disable the 262.
for that reason..ever been hit with a 30mm round..even one hits your la-7's wing and its GONE.
So your fast..you hit hard...you die fast.
there slower..they hit softer..they die faster.
Id be pissed if a 262 could take as much pounding as a p-40 or la-7 "iv taken' so much dmg in that plane..left wing tip..bolth landing gear up front..engi blown...and half my left vertical stabalizer..and i think my flaps..and i belly landed it on my runway going about 130..Im comein' in..everyone move!..scraaaaaaaaaaaaaaaaape.
*ejects*..whew..all in a days work.
its all about the game play.
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Well regarding the History channel back in 1998 they used to show history programs with accurate accounts now they just play on the myths people seem to like to hear, I guess they were short on ratings. Though I wouldn't disregard the History channel program about 262 entirely but I wouldn't take it to heart either. They mix many things that are questionable and ommit them too.
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I pretty much dismiss everything I hear on the History Channel. I can find so many mistakes it thier stuff, and I'm only an amatuer historian with an unfinished BA in history.
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HoHun: you may like the LW stuff, but this is getting too far I think:D
I never heard or read before that the 262 engines were hard to destroy by gunfire. On the contrary, they were the soft spot of the aircraft. And engaging bombers from 6 o clock, where is the point of entry from the .50 cal bullets but into the front!!
Maybe that's why Steinhoff rather wanted to tackle the escorts?
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Hi Angus,
>HoHun: you may like the LW stuff, but this is getting too far I think:D
Well, you're invited to provide information that shows I'm wrong :-)
However, you can't judge the toughness of the plane by quotes like "I shot at it until the engine exploded." Shoot at any plane long enough, and some part will fail - a chain is only as strong as its weakest link. For each story like that, there might be many unpublished records saying "I shot at it with no result", or even "I shot at it and missed" though in fact the engine was hit without taking visible damage.
That's why to establish that the Jumo 004B was inferior in survibability, we'd need a precise reason for that. Lacking this reason, it's safe to assume it was a typical jet engine with regard to battle damage, and jet engines have proven to be very survivable.
Regards,
Henning (HoHun)
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HoHun,
It is the resposibility of the person claiming that things are not as perceived to provide the information to back up that claim.
The long standing belief is that the 262's engines were very fragile, therefore you need to provide information that counters this. You have not done so. Until you do, nobody will agree with you.
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Originally posted by Karnak
The long standing belief is that the 262's engines were very fragile
Actually...
Here you are making a claim yourself. And it is up to you to substantiate it.
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:rolleyes:
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Oh I see, the "It is the resposibility of the person claiming that things are not as perceived to provide the information to back up that claim. " -part only applies to others...When you post something, that should immideately be recognized as a fact?
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If we can agree that jet engines are more survivable than piston engines, then Ho-Hun has a very valid point. So far no one has come up with any bulletproof explanation on why Jumo's should be an exception and be more fragile than jet engines in general.
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Sure we have. The toejamty materials in the Jumo make it much more fragile. Slight damage stands a very good chance of prompting the Jumo to tear itself apart. The freakin' thing had a tendacy to do that on its own. Add some rapidly moving chunks of metal and it only worsens the Jumo's chances.
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They weren't "lovely materials" , karnak. The alloys used couldn't stand the prolonged wear and temperatures of a long running jet engine,so the components suffered a long run DEFORMATION (not a breaking of components) wich caused malfunction and/or fires.
That doesn't mean the engine was made of toejam, or paper. The alloys used were all metallic, and they were as durable against instantaneous shock damage (as a bullet hitting) as any other alloy which could have been used had germany had the proper resources.
So stop the "lovely materials" argument because is simply baseless to the point in discussion here.
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Let's not forget that great slave labor craftsmanship either...
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Actually I never heard of Jumos blowing up with acceleration, what did happend was them flaming out. This was a common problem for all early jets AFAIK.
In fact I have never heard of them "blowing up" at all but I have heard of their very short overhaul time of 10-20 hours.
Perhaps all this random blowing up stuff was based on a mixup of the Me262 with the Me163 which had this problem early on, but even that was resolved for the Me163 when in service.
Now I dont know if the jumo was any more succeptible to instantaneus damage than any other early jet engine. The "lovely materials" is always used in reference to long term longevity not instanteneus toughness.
I dont have enough expereience with the Me262 in Ah to say the engines are ok or not.
But I do think the airframe, wings tail etc are awfully fragile. I have never read anything to say Me262 had weak airframe except the collapsing nosewheel.
If you dont find that agreeable Karnak well go find counter info on Me262 airframe fragility. ;)
Anyway I hate flying Me262 in AH and feel I have better chance of getting kills and RTB in a Bf109G6. I just know it better. :D
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I think what Hohun is trying to say is the three issues concerning the Jumo004 - "Projected engine life" "Engine reliability against random failures" "Resistance to battle damage" - are all different things and should not be confused.
Karnak and Guppy keeps confusing the three, and Swulfe somehow naturally assumes since "Projected engine life" and "Engine reliability against random failures" sucked on the Jumo, the "Resistance to battle damage" part would suck, too.
I don't think Hohun is trying to say jet engines would survive a barrage of 8x.50s at 50 yards or something. Just that our natural assumption in the way "oh hey, a bullet gets sucked into the engine. It's gonna blow up" is misguided.
I wouldn't know, I'm a total layman. My first impression to this thread was - "hmm.. I've also heard the jet engines were pretty frail. And to think something would be sucked into those turbines.. that's gotta cause a huge damage, right?".
But come to think of it, I heard those things going around, but I can't specify any kind of source. I assume a bullet sucked into a turbine will kill it, but I don't know why... and so far, from what I have read in this thread, nobody disagreeing with Hohun came up with something enough that should answer to the big "why?".
This is very interesting read.. carry on guys!
ps) Since so many other people who have posted previously in these sort of threads have stated "pilot anecdotes" and "rare instances and claims" mean nothing, and objective chart, report, data, source is needed to confirm things, I think that sort of cancels out about 70% of arguments made here. Speaking objectively, that is.
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u know what a chart or writin record is?
its something that the pilots said and was written down............... that was made officail by a guy that had no clue cuz he wasn't there so a pilots story is just as valid as a peice of paper
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[LuftWhiner Mode On]
Nod2000, try saying that in some of the other simular type of threads - for example, the discussions concerning the power and trajectory of Hispano cannons in AH that happened way back. Or some discussions concerning how some planes like the Spit9 or N1K2 rarely feel serious torque in AH, and regained low speed maneuverability much too quick. It seemed awfully clear in those posts that "what the pilots say" don't count as "hard evidence".
:D
[LuftWhiner Mode Off]
Seriously though, I think what the pilots say should have some depth in these matters - but only as supplementary points. I've seen a lot of "pilot claims" that were refuted by careful analysis and research, and the general AH critics seem to agree on "don't believe all they say". Besides, I don't think pilots were exactly engineers and knew how a jet engine would work.
I think a pilot's stories are as much valid as they can afford to be - stories; some truths, some exaggerations, some lies.
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Are jet engines generally more resilient against a hail of gunfire than Piston engines, or not? I think they are not, however it is possibly easier to bury a jet engine behind armour than a Piston engine...hmm. Well, look at modern fighters, do they have externally mounted engines...hell, no, they really bury them within the central section. (Mind you that the reason why is probably more aerodynamic, bringing an armour possibility as a bonus).
So, Were the engines of the 262 armoured? Nope, not in any way, actually just the windscreen and the Pilot seat was armoured, since the main idea behind the design was that speed should keep this aircraft out of harms way.
So, we have a lightly armoured jet, with "naked" jet engines hanging under the wings. Good or bad service durability of engines, or genarally materials do not really matter, I still can't see how you can figure out that its durable at all
;)
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which kind of armor does the F16 carry around its engine? or a F15?
or the A10 (one of the thoughest planes flying today?).
well. All I say, is LOL ,angus ;)
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Well, Rram, they don't really. However......::D
A-10 has the engines mounted above the tailplane to shield them from enemy fire as well as making the engine exhaust a worse infra-red source from below. It can easily be flown on one engine, but damage/failiure to both engines will naturally bring it down, - for that it is designed to be a forgiving belly lander.
Now a brand new design, The SU-32:
"The crew¹s cabin has been designed in the shape of a single titanium bronze capsule, the construction of which was perfected on an Su-25 low-flying attack aircraft. There is defensive armour on the fuel tank, the engines and other vitally important parts of the aircraft. "
Speaking of SU's, the SU25 "Frogfoot" has engine armament and is known to have suvived hits from stinger missiles.
Now the F16 and the F15 are no close support aircraft, so a totally different design. They rarely return from a mission with bullet holes. In a dogfight however, they could be hit, presumably from the high 6, where the F15's entire wing section is over the engines, and the Fuselage of the F16.
hmmm, Rram, I don't know.:D
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Hi Angus,
>Speaking of SU's, the SU25 "Frogfoot" has engine armament and is known to have suvived hits from stinger missiles.
Actually, the decisive part of armour of the Sukhoi Su-25 is a shield between the engines so that catastrophic damage to one engine can't spread to the other one. This shield was added as the result of Afghanistan experience when damage from Stinger missiles could take out both engines even if only one was hit.
In short, protecting the engines against each other proved more important than protecting the engines against enemy fire.
Regards,
Henning (HoHun)
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yup HoHun.
That's because there is two of them.
(one as a backup):D
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I shot down a 262 once with the 2 &.62mm machine guns in the 109F. Took less time and ammo than I expected.
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In peace time jet engines are more reliable
It's a fine precion thing working under high revs
a litlle crack or a different composite alloy from the metal fins could do great damage to the engine and let it blow up easy
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Angus apparently you have not seen pics from F15Es returning from NOE missions over in Iraq in 1991 during the Gulf War.
You'd be surprised at the number of bullet holes the thing had when they landed.
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Some of you say that jet engines are durable some of you say they are not. Some of you say 262 was durable in RL, some of you say it was pretty fragile.
And even some of you say that 262s in AH are udermodeled (when talking about DM) knowingly and on purpose.
Well if the fragility of 262 in AH is intentional then I say: Cut the price of 262 to half and stop the whining
All of you know that when you fly 262 then every plane you meet starts spraying in your general direction hoping for random lucky hit that will most likely knock a piece of your plane off...
Good pilots will make kills in a undermodeled plane anyway and stupids will die as they do right now too. I think engine fragility in 262 we have is OK but I also think that the airframe is a bit too fragile... even few pings from .50 at distance over 1k knock wingtips airleons etc... But thats prolly because .50s are tank busting bullets (i still keep forgeting about this fact)
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I'm pretty surprised that no one has really disputed the "jet engines are more durable than piston engines in combat" claim yet. Guess there are no suck and blow techs in AH. :)
The late war radial engines were far, far more durable than any jet engine will ever be. Period. Many documented cases exist were radials continued to operate with entire pistons shot off, for example.
Jet engines still need oil to run, in fact because of the high RPM's and close clearances oil is critical.
Bullet holes in the engine casing aft of the turbines will cause hot air leakage that almost always will result in a fire (even in modern engines).
As many have pointed out, "FOD" (foreign object damage) is death to a jet engine, even today. Basically anything going down the intakes (bullets, shrapnel, birds, whatever) will result is serious, possibly catastrophic engine damage.
The only western jet that I am aware of that has “armored” engine bays is the A-10, which can withstand up to a 23mm hit if memory serves. Most modern jet engine cases are made from titanium, but that is more for high heat / low weight reasons, and certainly not intended as “armor”.
-Smut
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Hi Smut,
>The late war radial engines were far, far more durable than any jet engine will ever be. Period.
Hm, I think I'd like to see some evidence supporting that claim if you happen to have some.
The Korean war jets - both MiGs and Sabres alike - were very tough. In Vietnam, the Navy replaced the radial-engined Skyraiders that were flying in the highly dangerous ground-attack role were replaced by jet-engined Skyhawks. The Air Force replaced their radial-engined B-26 Invaders who were mainly threatened by ground fire as well with jet-engined B-57B Canberras. (One of the rare instances were Navy and Air Force agreed on something :-)
>Many documented cases exist were radials continued to operate with entire pistons shot off, for example.
Many documented cases exist where jet engines operated with no pistons at all ;-) I understand what you're aiming at, but I'm afraid damaged pistons are not a useful point of reference.
Regards,
Henning (HoHun)
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"""Many documented cases exist where jet engines operated with no pistons at all """
gee, i always thought if a jet lost it's pistons it was done for the day, shows how dumb i am.
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the Jumo's along with any other non titanium combustion cased Engine , along with balancing factors and air density's vs fuel flow vs internal temps (alias hot spots) made early jet engines very fragile. anything injested by the engine would create a failure, along with improper handling of the throttles.
There is also compressor stalls and shifts to think about to, and the fact that a cracked blade will most likely break and ruin the whole engine.
As for the Jet engine being more durable and withstanding hits then a piston engine . it is not ,
The jet is faster , the engines are a smaller target to hit .(from most angles of attack)
The piston engine can break a con rod, valve ,have a magnito fail , ect. and will still run for sometime.
btw the A-10 wasnt the only plane with armor plates around their engines. ( I've handled plenty of bullit riddled Armor on the T-64's engines in HH-53's when i was in the service)
One more point to add jet engine planes have not seen the type of combat as the WW2 planes saw . (how many times did B-52's get straffed by the masses ?)
so in closing here .. you can toss rocks at a piston engine ,but can you toss rocks at a jet engine ???? Do I need to Say more ?
Jet Engine mechanic U.S.A.F 1982-86
"If it wasnt for the jet we would never have to do F.O.D walks"
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Hi Roscoroo,
>anything injested by the engine would create a failure, along with improper handling of the throttles. There is also compressor stalls and shifts to think about to, [...]
Well, I think this is only very remotely connected to the question of survivability.
>and the fact that a cracked blade will most likely break and ruin the whole engine.
I just read about one (civilian) aircraft with the big radial engines which recently had a rod break, ruining the whole engine. Catastropic damage is always a possiblity.
>The jet is faster , the engines are a smaller target to hit .(from most angles of attack)
I think this is called susceptibilty, and it has an objective and direct influence on survivability.
>One more point to add jet engine planes have not seen the type of combat as the WW2 planes saw . (how many times did B-52's get straffed by the masses ?)
True for the B-52s, but aircraft like the A-4, the B-57 or even the F-100 in the FAC role had to deal with old-fashioned ground fire from projectile weapons mainly. And the MiGs in Korea certainly were strafed by WW2-type guns (only firing much faster and with a denser pattern) and still proved very tough.
Regards,
Henning (HoHun)
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sometimes i get alittle carried away ... the original question is ME 262's durability . in combat vs a prop job .
here is a cool jet engine sim program if you dare to create a Jumo type jet engine and test it , it has different alloy types for each section of the engine , and you can play to your hearts content..... its a fun program btw
http://www.grc.nasa.gov/WWW/K-12/airplane/ngnsim.html
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Hi Roscoroo,
>sometimes i get alittle carried away ... the original question is ME 262's durability . in combat vs a prop job .
Since it couldn't be established that the Jumo 004B was more vulnerable than an average jet engine, Smut raised the question whether jet engines in general do indeed compare favourably to piston engines.
I think this is a good approach, and as you were contributing to the investigation of this question, please don't think you got carried away :-)
Regards,
Henning (HoHun)
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Now I'm going to add the Stormbirds website to this discussion for All the Guys/Gals to Read . For they are the most knowledgeable People on the ME262 . (they are Building Real ME262's there but using General Electric J-85's instead of Jumo's)
http://www.stormbirds.com/project/technical/technical.htm
As For The Jumo being durable in combat . It just wasnt possiable at that time .The substandard of metals used in the Jumo's and a Life of 10-20 hours .providing they didnt shell out on start-up basically says volumnes about the quality/ reliability of the Jumo.
Also the Russian Mig Engines Pre 70's were not a very reliable either. (the non use of titanium gave them a very short life under Mil. throttle settings)
Todays Jet Engines get run tested befor installation on an aircraft. Your not going to hear about them shelling out because of this on aircraft .
the average jet engine usually gets overhauled at 10,000 hours,with the compressor section getting overhauled at 30,000 hrs ,
So if we compare todays jet engine to piston engines we find that yes it is way more reliable . But back in the 40's and early 50's the piston engine was way more reliable . as for in combat most of you never heard of how many jet engines were changed out after landing ( alot more then piston engines )
A vibration would be cause for removal of a jet engine , and in a piston engine a vibration ussually ment you needed to change a spark bolt.
Well I had a great post here until my 1 1/2 year old copilot came by and hit the reset button on my PC and I lost my chain of thought , but I find this discussion alot better them most of the garbage on these boards All
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Roscoroo, one of the points Ho Hun is trying to get across is that reliability and combat survivability of an engine are two separate things and not necessarily connected.
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SageFIN,
He's right in that they are not necessarily connected, but in the case of the 262 they are. He has yet to show one iota of data that the 262's engines were durable. He insists on ignoring the only data, admittedly of the personal account type, that we have and insists that his opinion, unsupported by data, is correct.
Frankly, he's coming off as a demagogue.
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Hell- I gave a freaking diagram of the engine.
It's obviously a very easy target to hit being underneath the wings, it has no armor around the engines, and a barrage of .50s cals ain't gonna be shrugged off lightly by an engine that DID have problems falling apart. Hint: the rotor blades were known to rip off.
So you get some foreign material in there (.50 cal), it pierces the engine, flies through the compression chamber forward of the compressor blades and you are gonna have a helluva lotta material getting sucked into those compressor blades.
It ain't no A-10 engine, which was designed to take crap like that, it's a first generation jet engine that's highly vulnerable to enemy gun fire.
-SW
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Frankly, he's coming off as a demagogue.
who is ????
I'll I have done is given all of you places to look, read,and experiment for yourselves . You can come to your own conclusions.
In my opinion based on the Facts I have read,and been taught. the Jumo engine in the ME262 is great piece of engineering that issued us into the jet age. But it is a substandard pile of junk with no reliability.
If the Germans would of kept using top grade metals and had more time for testing and quality control for the engines . these planes could of put a big dent in the Allied bombing raids, as they are, they were lucky to get off the ground make one straffing pass and land safely .
We must also look at the fact that these are turbo jet engines not turbo fans (like in the A-10 ) a turbo fan has a seperate turbine and the front fan section , and the big fan out front is used for thrust not for compressing air into the engine . in this configuration the fan can ingest foriegn objects and spit them out without near the damage that a turbo jet will go thru if even a single rock goes thru it.
I believe if there would of been more ME262s harrasing the Allied Buffs that we would have came out with a Shaff or shrapnel launching device (kinda like a defensive flak thing) that would of really put a stop to the ME262's abilitys. (why shoot bullits when all you have to do is toss used tin beer cans at it to ruin it ? )
HoHun is just trying to have a good Discussion going on here .
Oops getting carried away again :D
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Does anyone have any credible evidence of jet engines being better at taking damage than piston engines? There have been of engines exploding because of a single compressor blade cracking off, on modern jet engines. I seriously doubt that a jet engine will survive more than a radial piston engine.
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Hi Karnak,
>He's right in that they are not necessarily connected, but in the case of the 262 they are. He has yet to show one iota of data that the 262's engines were durable.
As I've already pointed out, the Jumo 004B was designed to deliver the same power as the Jumo 004A that used high-quality alloys. This means that the turbine blades from substitute alloys were able to take the same mechanical stresses as the high-quality blades. They did not have the same longevity, though, but damage resistance is mainly determined by the ability to take mechanical stress.
You can find an explanation of the cause of the Jumo 004B's short engine life at the site pointed out by Roscoroo:
http://www.stormbirds.com/project/technical/technical.htm
>He insists on ignoring the only data, admittedly of the personal account type, that we have and insists that his opinion, unsupported by data, is correct.
Battle survivability is a statistical process. Personal accounts of Me 262 kills aren't random samples that would enable us to determine Me 262 durability, not even for a rough estimate. To arrive at such an estimate, you'd have to include the unsuccessful attacks on jets for the same set of pilots and missions. That's a mathematical requirement I'm not responsible for :-)
>Frankly, he's coming off as a demagogue.
Which is a good example for a demagogical statement itself :-) This is a pretty ordinary forum discussion, no need to get overwhelmed by bad vibrations!
Regards,
Henning (HoHun)
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Hi Rocoroo,
>http://www.stormbirds.com/project/technical/technical.htm
Good link, thanks!
>So if we compare todays jet engine to piston engines we find that yes it is way more reliable . But back in the 40's and early 50's the piston engine was way more reliable .
As I pointed out repeatedly, reliability and survivability aren't necessarily connected. The answer for the reliability question is probably much easier to find, and we could open another thread for that if you like :-)
(You might have heard of the Lockheed Constellations being referred to as "the world's most beatiful trimotor" since it was quite common for the airliner to arrive at its destionation with one of the big radials off and its propeller feathered :-)
>Well I had a great post here until my 1 1/2 year old copilot came by and hit the reset button on my PC and I lost my chain of thought , but I find this discussion alot better them most of the garbage on these boards
Too bad about the reset! I think the standard mod consists of adding a master arm switch in the front seat to prevent accidental operation of the reset button by unqualified crewmembers ;-)
Regards,
Henning (HoHun)
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HOW RELIABLE IS AN ENGINE THAT HAD TO BE REPLACED AFTER 24 HRS FLIGHT TIME ????
:rolleyes:
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If were gonna discuss the reliability of jets vs prop planes then perhaps we need a time frame here such as 1940-52 /57
by 1958 is when most of the bugs of engineering were worked out of the jet engine.
we can do a 1958-70 comparison to ... just to have fun with it .
I 'd gladly drag up some more objective web sites . for im not biased either way when talking about this stuff .
And its a great way for everyone to learn . Go ahead start another thread if you want :)
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Embry-Riddle in daytona beach florida purchased 3 Jumo 004's (D or E model i think) many years ago. I talked with a professor that runs the turbine engines lab and teaches engine courses for pilots there. The first engine wouldnt run at all even though it appeared to be in good order. The second engine ran and was played with in one of the test cells for a while, until a carpenter walked a little too close in front of it while it was in operation. It sucked the roofing nails out of his tool pouch, damaging the compressor blades enough to render it inoperable. This engine is now on static display at the school, and is cutaway so that you can see the internals, and also the little dings on the compressor blades made by the nails. The 3rd engine was never run and donated to a museum some years later. I will try to supply pictures of the Jumo on display at the school. The little dings in the compressor blades were enough to stall the blades and cause catastrophic failure in a matter of seconds.
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Hi Flaps,
>Jumo 004 (fairly) recent experience story
Try that with any jet engine, and the results will be similar.
Ingestion of foreign objects is not the same as getting shot at.
It could be a concern in combat, and Me 262 tactics included passing over the top of bomber formations instead of diving below it to avoid ingestion of debris from damaged bombers. However, I don't think this is a reason to doubt the survivablity of the Jumo 004B engines.
Regards,
Henning (HoHun)
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Well I think survivability and combat reliability kind of go hand in hand here . say you have a engine (it doesnt matter what type) that will break easy under sudden high boost pressure ,prop overspeed,unable to withstand a spike in temperatures,in case of a jet engine a compressor shift when decreasing or increasing rotation speed. This all adds into how capable a aircraft can dogfight.
I would like to know how anyone could get that close to a running engine in a test cell to have nails endup ingested into it .
I could see it happening but it sounds more like a flight line- prop wash story to me. (its probly fod ingestion from the flightline or rubbing of the compressor blades)
I was stationed at a Depot level base and spent many hours (on boring Grave shift nights) hanging out with all the civilians (the evil "hearts" player types) that worked in the engine shop and over in the test cells during many run ins and tests. along with being engine run/trim qualified on WC-135B's w/ TF-33 's , I have also been within 2 - 3 feet of a Running prop on C-130's
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if anyone is interested there is an article titled 'flying the me262' (or something like that)written by a guy who did so in the sept 2002 Aviation History magaizine. the only unusual things mentioned about the engines, with regards to their performance, was the lack of fuel injection and the good possibility of an engine catching fire during the starting procedure. whenever the 262 was started a team of firefighters was close at hand
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Hi Roscoroo,
>This all adds into how capable a aircraft can dogfight.
In the case of the Me 262, the main limitation of the engine was that it would not take any quick throttle changes. However, jet tactics didn't call for quick throttle changes (or dogfighting), so this wasn't much of a tactical problem.
The cause of the limitation was the the engine control system, so it was not a question of mechanical reliability. Junkers had a better system eliminating the problem ready at the end of the war, but it didn't get into production.
In short, there's no connection to the engine's battle survivability.
Regards,
Henning (HoHun)
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Hi Whgates,
>whenever the 262 was started a team of firefighters was close at hand
This was standard operating procedure for piston engines as well. Nothing special about the Jumo ...
Regards,
Henning (HoHun)
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Originally posted by HoHun
Hi Smut,
>The late war radial engines were far, far more durable than any jet engine will ever be. Period.
Hm, I think I'd like to see some evidence supporting that claim if you happen to have some.
Sorry, I'm not going to dig through my references just because you don't believe me. Read virtually any combat account of the P-47, F4U, or F6F for examples.
Originally posted by HoHun
The Korean war jets - both MiGs and Sabres alike - were very tough. In Vietnam, the Navy replaced the radial-engined Skyraiders that were flying in the highly dangerous ground-attack role were replaced by jet-engined Skyhawks. The Air Force replaced their radial-engined B-26 Invaders who were mainly threatened by ground fire as well with jet-engined B-57B Canberras. (One of the rare instances were Navy and Air Force agreed on something :-)
The A-1's were replaced by A-4's not because they were less durable, but because they were slow and out of production. The same goes for the B-26...the problem wasn't the engines, it was metal fatigue (wing spars, as I recall).
Ground fire had nothing to do with it. AC-47's flew for most of the war, for example.
Originally posted by HoHun
>Many documented cases exist were radials continued to operate with entire pistons shot off, for example.
Many documented cases exist where jet engines operated with no pistons at all ;-) I understand what you're aiming at, but I'm afraid damaged pistons are not a useful point of reference.
You are being dense. The point is that there are documented cases where radial engines continued to operate even after suffering major damage. Take something as simple as a birdstrike. No big deal to a radial engine aircraft, however it can be deadly to a jet...and before you spout off "but that's not combat", I submit that it is an example of a jet engines inability to tolerate any type of internal damage.
On a related note, does the expression "Bleed air leak" mean anything to you?
-Smut
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I'm just going to add more sites here for your reading enjoyment . this way everyone can come up with there own conclusions . this will draw us into the jet age here more then the me 262 , Im trying to stick with goverment/ FAA/nasa,and manufactures web sites . so start reading . Tee Hee .
http://www.hq.nasa.gov/office/pao/History/SP-468/contents.htm
The B-45 and the B-47 here ....(the 1st production jet bombers)U.S.
http://www.hq.nasa.gov/office/pao/History/SP-468/ch12-2.htm
The B-58 my favorite jet .This plane was way ahead of its time.
http://www.hq.nasa.gov/office/pao/History/SP-468/ch12-4.htm
next i will compare the problems of early jet fighters and their relatively limited range and endurance as compared to their piston-engined predecessors.
What im trying to do here is to open the discussion up enough so everyone can read about the early problems with jet engines vs piston and the airframes ect. Then i'll go back to the reliabilty/combat discussion of the me262 vs props .
Im really bummed that we have to pay to see the online encyclopidia Brittanica online these days .
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Originally posted by Montezuma
Let's not forget that great slave labor craftsmanship either...
Yeah, jsut where was Bob Vila?
Originally posted by Karnak
Sure we have. The toejamty materials in the Jumo make it much more fragile...
Lol, great descriptive language
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I have to give some credit to you HoHun;)
You really know how to put up a fight
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Hi Smut,
>The A-1's were replaced by A-4's not because they were less durable, but because they were slow and out of production. The same goes for the B-26...the problem wasn't the engines, it was metal fatigue (wing spars, as I recall).
It remains a fact that both the Navy and the Air Force replaced radial-engined aircraft types that were employed in a role where ground fire was the main threat with aircraft types that relied on jet engines. Since both services cared very much about whether their pilots returned safely or got shot down, there was obviously little (if any) concern about the survivability of jet engines.
>You are being dense. The point is that there are documented cases where radial engines continued to operate even after suffering major damage.
I'm afraid I should have reminded you of some basic statistic knowledge: You don't get representative results from arbitrarily limited samples.
Anecdotal evidence does not tell you anything about survivability since it's only based on cases where the engine survived. To get a realistic number, you'll have to include the engines that took hits and died. A value like the loss ratio per fighter bomber sortie would be a (semi-)decent indicator for survivability, for example.
Any kind of engine can suffer catastrophic failure. For the question of survivability, the question is - what's the probability of the event that causes catastrophic failure? That's why listing single events like birdstrikes is not going to lead anywhere if you leave open the probability associated with them.
(The world is full of birds, and in the last 50 years, countless jet take-offs and landings have taken place. Still, in these 50 years only 400 people have died due to bird strikes worldwide, including those flying propeller planes. Pretty unconnected to combat operations, but as I coincidentally came across this number today, I thought I'd share it with you :-)
Regards,
Henning (HoHun)
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Originally posted by HoHun
This was standard operating procedure for piston engines as well. Nothing special about the Jumo ...
read p.12-14 of sept 2002 aviation history & i think you will realize that the reidel starter for the me262's jumo 004s was a quite a lot less safe than any WWII piston engine plane
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Hi Whgates,
>i think you will realize that the reidel starter for the me262's jumo 004s was a quite a lot less safe than any WWII piston engine plane
Actually, the Riedel starter was a WW2 piston engine; an opposed 2-cylinder 2-stroke engine of 270 cm^3 cubic volume delivering 10.5 HP.
The problem when starting the Jumo 004B was that an amount of unburnt fuel could be blown out of the rear of the engine during the starting process. (If you look at recent pictures of the Me 262 replica fitted with modern jet engines, you can see that the Jumo isn't unique in that regard; Flugzeug Classic published a poto showing the port GE J85 sending a one-metre flame out of the exhaust during start-up.)
The amount of fuel being ejected from the Jumo could be enough to start a fire on the runway, which then was put out by the groundcrewman with his fire extinguisher. The effect was a tactical limitation for the Me 262 as it meant it couldn't safely operate from grass fields routinely, but concrete runways were better for launching jets anyway.
Not that this has anything to do with battle survivability ...
Regards,
Henning (HoHun)
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Originally posted by HoHun
It remains a fact that both the Navy and the Air Force replaced radial-engined aircraft types that were employed in a role where ground fire was the main threat with aircraft types that relied on jet engines. Since both services cared very much about whether their pilots returned safely or got shot down, there was obviously little (if any) concern about the survivability of jet engines.
:rolleyes:
You are warping history to suit your own agenda.
1. Speed, not durability was one of the reasons the A-1 was replaced by the A-4. 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. Faster = less exposure to ground fire.
2. I thought this thread was about the 1944-45 era Me-262 and its engines, not aircraft that came 20 years later. Twenty years is a LONG time in aircraft engine evolution terms.
Originally posted by HoHun
I'm afraid I should have reminded you of some basic statistic knowledge: You don't get representative results from arbitrarily limited samples.
I'm afraid I should tell you that, as a Reliability and Maintainability Senior Engineering Technician, I am quite familar with "basic statistic knowledge".
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".
I should also tell you that while I am not a powerplant specialist, I have had enough aircraft combat system survivability training (and real world experience) to have a pretty good understanding of what can go wrong in a modern tactical jet aircraft.
Does the term "FOD" mean anything to you? FOD is death to a jet engine...modern or WW2 era. Considerable effort is expended every single day at every single airfield that operates jets to control FOD. I'm sure you will dismiss FOD as "not combat related" in which case you are only showing your lack of knowledge. The "F" in FOD stand for "foreign", as in "foreign object damage". A foreign object can be a bird, a screw, loose change, a bullet, shrapnel...whatever.
Such FOD control measures are not required at airfields that don't operate jets. Hmmm...
Originally posted by HoHun
(The world is full of birds, and in the last 50 years, countless jet take-offs and landings have taken place. Still, in these 50 years only 400 people have died due to bird strikes worldwide, including those flying propeller planes. Pretty unconnected to combat operations, but as I coincidentally came across this number today, I thought I'd share it with you :-)
1. How many of those 400 people were on jet powered aircraft, hmmm? You seem to have ignored that little factiod.
2. If you think that birdstrike damage is unconnected to combat operations, you don't have a good understanding of how aircraft are used in combat.
-Smut
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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)
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So Jet engines now eat birds with no problem whatsoever?
What next HoHun?
Well, it just so happens that most jets today are twin engined and easily fly on one engine. A bird into the engine of an airliner is quite a thing, and just a pebble into the engine of an F-15 can do some expensive damage. I recently visited a U.S. airbase, where the car I was in was stopped and the tires examined to eliminate the possibility of pebbles being carried onto the flightline!
In this thread there has been quite some discussion about the Jumo engine catching fire if the throttle was moved too quickly.
An old 262 pilot once explained this to me. It was simply a technical thing that could be cured with a mechanical device which today is called a regulator. The 262 just didn't have it.
Next time I hear from him I'll ask him about combat durability:D
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Hi Angus,
>So Jet engines now eat birds with no problem whatsoever?
If that's the impression you gained, I'm afraid my explanation wasn't as clear as I had hoped. It's obvious that bird strikes can have catastrophic consquences. However, the low number of lethal accidents shows that the probability of a bird strike with catastrophic consquences is very low.
>In this thread there has been quite some discussion about the Jumo engine catching fire if the throttle was moved too quickly.
An old 262 pilot once explained this to me. It was simply a technical thing that could be cured with a mechanical device which today is called a regulator. The 262 just didn't have it.
No doubt about that! Here's what I wrote on that topic earlier in this thread:
"In the case of the Me 262, the main limitation of the engine was that it would not take any quick throttle changes. However, jet tactics didn't call for quick throttle changes (or dogfighting), so this wasn't much of a tactical problem.
The cause of the limitation was the the engine control system, so it was not a question of mechanical reliability. Junkers had a better system eliminating the problem ready at the end of the war, but it didn't get into production."
>Next time I hear from him I'll ask him about combat durability:D
Make sure to post his answer here, I'd love to know it! :-)
Regards,
Henning (HoHun)