Dogfight: Me 262 vs. Meteor

[kool kitty89]

The meteor also suffered chronic problems with its armament when taking on V1s
from wiki
All other types combined added 158. The still-experimental jet-powered Gloster Meteor, which was rushed half-ready into service in July 1944 to fight the V-1s, had ample speed but suffered from unreliable armament and accounted for only 13.

That was with the Meteor Mk.I, I believe that problem was resolved with the F Mk.3, though structural issues still limited allowable aileron response (and roll rate accordingly) and the problematic short-chord nacelles remained in use on all the Meteor 3s actually fielded. (the first few also continued to use 1600 lbf Welland engines, leaving them underpowered, while the 2000 lbf Derwent I would have only closed the gap for the Me 262)

The Meteor 3s actually sent over Europe in 1945 would have been no match for the Me 262 in any sort of real air to air combat, though they should have been just as capable as other allied fighters at shooting them down on take-off/landing.

The Me 262's cannon may not have been ideal for dogfighting, but it was far from useless and not really worse than the MG-FF of the Bf 109E or Fw 190A-1 in that respect. (somewhat lower velocity but higher sectional density and better ballistics on the streamlined high-explosive-incendiary-tracer rounds along with a higher rate of fire per gun, higher ammunition capacity, centerline mounting, and 4 guns to the 109's 2)

 

[GrauGeist]

I recall seeing a clip from a Me262's gun camera footage where the 262 got in behind a P-51 and snapped off a volley. The fuselage and starboard wing on the P-51 were devastated.

Those Mk108s were not to be taken lightly.

 

[Juha]

The meteor also suffered chronic problems with its armament when taking on V1s
from wiki
All other types combined added 158. The still-experimental jet-powered Gloster Meteor, which was rushed half-ready into service in July 1944 to fight the V-1s, had ample speed but suffered from unreliable armament and accounted for only 13.

IIRC those gun problems were quickly corrected.

Juha

 

[thedab]

What get me,is why the Garmans didn't put dive brakes on the 262,as couple years before,they were putting dive brakes on anything with wings.

 

[GrauGeist]

What get me,is why the Garmans did put dive brakes on the 262,as couple years before,they were putting dive brakes on anything with wings.

Because speed was the Me262's best defense. The jet engines were slow to spool up and deploying dive-brakes could put the 262 into a dangerous situation.

 

[kool kitty89]

Because speed was the Me262's best defense. The jet engines were slow to spool up and deploying dive-brakes could put the 262 into a dangerous situation.

That's the very reason you'd want dive breaks: don't throttle the engines, keep them at/near full RPM and use breaks to slow down if needed. Using them to shorten landing runs would be useful too. (and assist with high speed dive recovery)

 

[FLYBOYJ]

That's the very reason you'd want dive breaks: don't throttle the engines, keep them at/near full RPM and use breaks to slow down if needed. Using them to shorten landing runs would be useful too. (and assist with high speed dive recovery)

That's a technique that could be used on later turbine fighters. You could not operate first generation jet fighters at full RPM for no more than 5 minutes.

 

[GrauGeist]

That's the very reason you'd want dive breaks: don't throttle the engines, keep them at/near full RPM and use breaks to slow down if needed. Using them to shorten landing runs would be useful too. (and assist with high speed dive recovery)

The Me262 had a high stall speed, anything beyond the flaps provided would most certainly shorten it's landing run - by several hundred feet...

 

[davparlr]

The T-37 used both speed brake and thrust attenuators (small speed brake extending into the engine exhaust flow) on final approach to keep RPMs higher allowing better performance for possible go around and touch and gos. Centrifugal flow engine accelerate poorly so if RPM on final was near idle, safe go arounds were problematic.

 

[FLYBOYJ]

The T-37 used both speed brake and thrust attenuators (small speed brake extending into the engine exhaust flow) on final approach to keep RPMs higher allowing better performance for possible go around and touch and gos. Centrifugal flow engine accelerate poorly so if RPM on final was near idle, safe go arounds were problematic.

When I flew the L29 (a centrifugal flow engine) I always came in a little hot and at a slightly highter rpm setting then the "recommended settings" just because of that. Shorter airfields could present a problem but most of my landings were on huge runways (Mojave, Point Mugu, El Centro, March) The speed brakes worked well as well as keeping the nose up during roll out for maximum aerodynamic braking.

 

[awack]

I believe air brakes would have been a plus, Galland has stated in his opinion that they would have not have been worth it, slowing down the 262 in a sky full of enemy fighters was not a good idea, but in my opinion, they could have saved a lot of lives, in my reading of 262 kills the majority were achieved during take off, landing and especially the long approach to the air field, where the 262 has to slow down well in advance of gears down. As every one knows, the me 262 could fly around all day long at full throttle, high command put a limit of 15 minutes for 2 reasons, one being engine life, and the other was fuel consumption, but as test pilots have said, they had flown for 20 minutes or more with no problems.. this of course gave it yet another huge tactical advantage it had over its enemies, every thing I can find regarding early centrifugal flow jets, like those of the Meteor, give a limit of 5 minutes.

The war time Meteors are of course not in the same league as the 262, but I always thought that an interceptor variant of the ar 234 b would have made a good comparison to the meteor mk3 with derwent engines, the ar 234 tested after the war in the UK and the US in clean configuration (no bomb/drop tank racks, no periscope and no parachute cable) gave it a top speed of between 475 mph and some where over 480 mph.

 

[GrauGeist]

Again, the problem with dive-brakes on the Me262 is building up speed once they've been deployed.

The high rate of closure to the bombers was actually to the Me262's advantage, as it minimized exposure to defensive fire, as all it took to destroy a jet engine, was a single .50 slug. Once the pilots learned to compensate for the speed of the Me262, they developed very effective tactics that were nearly impossible to defend against. There are several books authored by the 262's pilots that go into great detail of this.

Using anything other than landing flaps on the Me262 during the landing process would put the aircraft and pilot into jeopardy, as the Me262's stall speed was much higher (between 112/125 mph - 180/200 kph depending on fuel/weapon load condition) than a piston aircraft AND the Me262 did not have the benefit of the prop assisting in generating lift (although the leading-edge slats did deploy and assist in providing additional lift below speeds of 190mph/300kph) after the 262 has started it's approach. The safe approach speed was 155 mph (250kph).

 

[FLYBOYJ]

the me 262 could fly around all day long at full throttle, high command put a limit of 15 minutes for 2 reasons, one being engine life, and the other was fuel consumption, but as test pilots have said, they had flown for 20 minutes or more with no problems.

I'd like to know specific references for that. You cannot safely continually fly a turbine engine at 100%. The 262 had a limitation of 5 minutes at 100% for take off and had a "military' restriction of 10 minutes at 100% (8700 rpm). After that the aircraft was flown at 90%. These figures came straight from the original 262 operating instructions and were also transcribed in USAAF summary Report FSU-111-ND dated 15 July 1946. This document is basically the transcribed flight manual used by Wright Patterson AFB personnel to fly and test the Me 262.

For the record;

P-80C had a 100% RPM limitation for 30 minutes. Exceeding 100% RPM could result in an overspeed inspection or teardown in excess of 110%

A Meteor MK VII with a Derwent 8 or 9 had a 15 minute limitation at 100% (14,700 rpm)

As with the 262, those limitations are directly from the flight manual/ pilot notes.

 

[awack]

Yeah, you can find the pilots hand book document at zenos warbird videos page, the site also has a document called summary of debriefing of me 262 test pilot and flight instructor Hans Fay, he was told that 15 minutes was max, but had flown for 20 minutes with no problems, Fay mainly tested the 262 at very low altitudes, he never flew higher than 13000 ft, I think most testing took place at 3300 ft, and from my understanding, they didn't fill the aux fuel tanks for testing, so 20 min wouldn't be far off from max endurance in those conditions.

There are other documents that would take me fore ever to find. supposedly there is Russian info of the 262 flying at full throttle as long as the speed is kept above 320 or so mph, from my understanding, this has been incorporated into video games/flight sims, I don't play flight sims so I wouldn't know.

Early jets for me are from 1939 too 1946 I don't know a lot about them past that date, I didn't know that about the p80c and Meteor mk VII.

 

[FLYBOYJ]

Yeah, you can find the pilots hand book document at zenos warbird videos page, the site also has a document called summary of debriefing of me 262 test pilot and flight instructor Hans Fay, he was told that 15 minutes was max, but had flown for 20 minutes with no problems, Fay mainly tested the 262 at very low altitudes, he never flew higher than 13000 ft, I think most testing took place at 3300 ft, and from my understanding, they didn't fill the aux fuel tanks for testing, so 20 min wouldn't be far off from max endurance in those conditions.

There are other documents that would take me fore ever to find. supposedly there is Russian info of the 262 flying at full throttle as long as the speed is kept above 320 or so mph, from my understanding, this has been incorporated into video games/flight sims, I don't play flight sims so I wouldn't know.

Early jets for me are from 1939 too 1946 I don't know a lot about them past that date, I didn't know that about the p80c and Meteor mk VII.

Despite the fact that someone was dumb enough to fly a 262 at 100% 20 minutes or more doesn't mean it could be done continually, that's my point. The limitations were set because someone KNEW that continual full power operations will destroy a turbine engine and you could find limitations in early jets as well as second generation jet aircraft. It's not only the engine affected, you could overheat the tailpipe, adjacent structure, engine accessories and even set up airframe harmonics that will cause structural damage (depending on the aircraft).

Yea, I could see some gamers latching on to the belief that you could fly an Me 262 at 100% continually. I know we had some gamers around here who knew how a B-2 flew because they had the sim program downloaded on their home PC.

 

[Shortround6]

I have read one account of Pilots taking delivery of P-38s at the end of the war from the factory and essentially flying them at WEP settings from take-off to approach for landing. The planes were the last of the contract and were pretty much heading for the scrap yard. The engines seemed to stand up to it but then they weren't flown more than a few hours afterward if at all.
Point is that a few anecdotes do not really translate into operational capability.

 

[kool kitty89]

From what I understand of the Jumo 004B (or at least the B-3 and B-4), running at max RPM wasn't nearly as damaging to the engine as allowing overheating conditions and/or making numerous rapid throttle movements. RPM wasn't limited by mechanical stress considerations, but by vibration problems at higher RPM (solving those on the 004D allowed nominal RPM to be increased to 9000 and substantial overrev to also be possible). Running the 003E at overrev settings continuously would likely be more destructive as that was actually possible, the 004B could not overrev and I was under the impression that 100% throttle was also maximum continuous power so long as temperature remained within limits.

Mass pressure and flow also varies with altitude, so there may have been additional temperature and stress limits present at low altitude than higher up. (I'd imagine between the low intake temperature and pressure, engine temps at given RPM would be lower higher up than down low)

Specific fuel consumption also improves as RPM (and pressure ratio) increases, so cruising at max continuous power is usually most efficient. (still drag dependent)


Regardless of that, my original point was that the ideal regime for Me 262 engine operation would be maintaining maximum continuous RPM and making as few throttle changes as possible, with maneuvers (or hypotehtical air brakes) used to bleed of speed rather than throttle changes. Lack of a propeller also makes using throttle changes to slow down or reduce dive acceleration rather poor. In a steep dive, something close to 80% of the thrust comes from aircraft weight alone, so throttle near full or idle won't make that dramatic a difference while application of air brakes would make a very substantial difference. Throttling down rapidly should not have been harmful, but throttling up too rapidly would cause excess fuel to be injected before mass flow could catch up to compensate, causing the normally extremely lean mixture to become closer to stoichiometric and increase the temperature in the combustion chambers, turbine section, and exhaust. (potentially weakening the combustion chambers and leading to rupture and/or overheating the turbine blades and causing distortion, accelerated creep or even failure)

I'd think dive recovery flaps that not only added drag but also corrected pitch-down (and could operate within critical mach conditions) would be most useful. Like the P-38 and P-47, the elevator remained effective well into critical mach but became extremely stiff and if trim was applied (something possible even if the elevator was blanked thanks to the variable incidence tailplane) overstressing the tail to structural failure was very possible (as with the P-38 and P-47), thus making air brakes or recovery flaps located well forward of that high-stress area far more useful. (breaks mounted to the tail section of the fusalage akin to the F-86 may have been a bad idea)

 

[FLYBOYJ]

From what I understand of the Jumo 004B (or at least the B-3 and B-4), running at max RPM wasn't nearly as damaging to the engine as allowing overheating conditions and/or making numerous rapid throttle movements.

When you run at maximum RPM you are allowing "overheating conditions" and WILL eventually over heat, regardless of the engine. What no one is touching on is when you're operating at 100% + you'll eventually see the EGT start to rise and there's usually a max limit there (710c sticks in my mind)

RPM wasn't limited by mechanical stress considerations, but by vibration problems at higher RPM (solving those on the 004D allowed nominal RPM to be increased to 9000 and substantial overrev to also be possible). Running the 003E at overrev settings continuously would likely be more destructive as that was actually possible, the 004B could not overrev and I was under the impression that 100% throttle was also maximum continuous power so long as temperature remained within limits.

Mass pressure and flow also varies with altitude, so there may have been additional temperature and stress limits present at low altitude than higher up. (I'd imagine between the low intake temperature and pressure, engine temps at given RPM would be lower higher up than down low)

Specific fuel consumption also improves as RPM (and pressure ratio) increases, so cruising at max continuous power is usually most efficient. (still drag dependent)

Operating at maximum RPM limits is another turbine engine killer regardless of the make, as mentioned earlier, there are some engines that could be taken as high as 110% with no issues providing you don't exceed the manufacturer's limits.

Regardless of that, my original point was that the ideal regime for Me 262 engine operation would be maintaining maximum continuous RPM and making as few throttle changes as possible, with maneuvers (or hypotehtical air brakes) used to bleed of speed rather than throttle changes. Lack of a propeller also makes using throttle changes to slow down or reduce dive acceleration rather poor. In a steep dive, something close to 80% of the thrust comes from aircraft weight alone, so throttle near full or idle won't make that dramatic a difference while application of air brakes would make a very substantial difference. Throttling down rapidly should not have been harmful, but throttling up too rapidly would cause excess fuel to be injected before mass flow could catch up to compensate, causing the normally extremely lean mixture to become closer to stoichiometric and increase the temperature in the combustion chambers, turbine section, and exhaust. (potentially weakening the combustion chambers and leading to rupture and/or overheating the turbine blades and causing distortion, accelerated creep or even failure)

Between 80 - 90% is what you're normally operating at. You could go higher is you follow the indicated parameters, watching EGT and also watching your airspeed indicator insuring you're not over stressing the air frame.

stoichiometric? In my experience that term is normally associated with recips as the mixture can be controlled. An adverse stoichiometric fuel mixture in a turbine engine is something beyond operator control, and could tell you that most pilots don't even know what that is!

 

[GrauGeist]

I'd think dive recovery flaps that not only added drag but also corrected pitch-down (and could operate within critical mach conditions) would be most useful. Like the P-38 and P-47, the elevator remained effective well into critical mach but became extremely stiff and if trim was applied (something possible even if the elevator was blanked thanks to the variable incidence tailplane) overstressing the tail to structural failure was very possible (as with the P-38 and P-47), thus making air brakes or recovery flaps located well forward of that high-stress area far more useful. (breaks mounted to the tail section of the fusalage akin to the F-86 may have been a bad idea)

It's interesting that the general consensus is that the Me262 "needed" divebrakes/airbrakes.

Luftwaffe pilots were already familiar with a high rate of closure on the bombers from their head-on attacks done with the Bf109 and/or Fw190 interceptions. All the Me262 pilots needed to do, was adjust their method of attack to maximize the amount of time the Mk108s would be on target. This developed into a high-speed slashing attack from high above, crossing over the target in an angular dive, coming out the other side and start to climb and prepare for another pass.

At what point would divebrakes/airbrakes be necessary in the execution of this attack? Deploying divebrakes/airbrakes in the middle of a bomber stream would achieve two results:
1 - it would allow more exposure for the defensive gunners to put a round in your engine or other vital portion of the aircraft
2 - it would allow the escorts to gain closer ground to intercept you.

The Me262's best defense was speed. A diving Me262 could be caught, especially be a P-47, but the P-51 was very capable of catching a diving 262, also. Deploying "brakes" would also cost the Me262 precious time to build up speed again, robbing it's ability to climb up and away from harm.

Also touching again on the brakes for landing idea, the Me262's wings did not generate enough lift for it to land at low speeds, even with the leading-edge slats. The only time brakes would have been useful, is *if* they were deployed once the 262 had put all three on the runway, thus shortening it's rollout.

 

[BiffF15]

GrauGeist,

I could envision using dive brakes at the completion of a stern intercept to slow down the 262 as it entered weapons employment range to allow for longer aim and trigger time. Then the pilot would either climb away or execute a slight dive to get back to a desired speed / energy state then climb again. Using dive brakes would preclude using maneuvering to slow down meaning more controllable transition from high intercept speed to slower weapons employment / trigger speed.

As it returned to land the dive brakes would more quickly slow it from the safety of high speed flight to the tactically more dangerous pattern speeds. This would shorten its vulnerability time in a Mustang rich environment.

Cheers,
Biff