262 durability ?

[HoHun]

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)

[AKSWulfe]

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

[fdiron]

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.

[HoHun]

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)

[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.  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.

[HoHun]

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)

[Innominate]

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.

[AKSWulfe]

EDIT: here's a better photo



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

[Glasses]

Yes 50 cals are l337 tank busters too.

[Charon]

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

[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.

[whgates3]

never mind a small steel bolt - have you seen what a frozen chicken can do to one?

[NOD2000]

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

[whgates3]

5 kills - that scouting party is an 'ace' - not bad for guys would couldn't get into flight school

[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"