Mistakes in Aviation

[kool kitty89]

Where did i say the Meteor Mk.I was even close to the Me 262?

Well the Mk. I certainly had problems, but it did have one advantage over prop fighters, the top speed of ~410-420 mph was achieved at low level and thus gave it a good advantage there. (it would have been very successful against the V-1's if not for the jamming guns caused by flawed case ejection chutes) Granted the Me 262 in any operational for was greatly superior to the Mk I.

But remember the improvements in the Meteor III, the long chord nacelles (introduced after initial production, but also retrofitted) greatly improved compressibility problems and added ~75 mph to top speed even with the Welland (1,700 lbf) engines giving a top speed of ~495 mph, increased to ~520 mph with Derwent Mk. I engines. (and there were also Derwent II -2,200 lbf, and IV -2,450 lbf- but I don't know if they were used operationally)

Granted the Meteor III had the ailerons wired heavy to limit wing stresses and allow it to be cleared for aerobatics, resulting in a rather poor roll-rate.

The Meteor III was coming closer to the Me 262's performance, but still at a significant disadvantage in performance (except in a turn). And even in the F-4 meteor, the compressibility problems were significant, with bad snaking around .8 Mach and buffeting, exceeding the limiting Mach number (limited by the tail on these models) could result in violent shock-stalls sometimes with irrecoverable loss of control or structural failures. These were eventually addressed with a new tail on the F-8, allowing full control up to critical Mach with better characteristics when hitting crit Mach and a limit of ~.82 Mach.

The improvements to the Meteor came rater late in the war, but had there not been the problems from the horrible Rover arrangement the Meteor's development could have been nearly 2 years further along, and engine developments more so.

With either W.2/700 or Derwent IV engines (2,450 lbf) an improved Meteor should have been available much sooner, with improved airframe allowing full combat ability.(clipped and strengthened wings)

Not quite as the F-4 (with 2x 3,500 lbf engines) and still with Mach limitations of the tail, but probably somewhat lighter as well.

[i-kil-you]

i'd say the corsair because it was built for ww2, but was made just afterwards so it didn't get in.

[Haztoys]

Originally Posted by i-kil-you

i'd say the corsair because it was built for ww2, but was made just afterwards so it didn't get in.

...???...I "think' the Corsair was in WW11.. ..Or I'm reading this wrong....???

[kool kitty89]

??? You mean the F4U-5? Otherwise that makes no sense.

And the F2G "Super Corsair" turned out to be a failure.

[Haztoys]

I know one of the heels of the Me-262 was you could not spool up or down the engines very fast ...I can see were this would be a real problem in combat ... Could the Meteor engines be spooled up and down fast...

Or were all jet engines of the time that way...???

[buzzard]

Despite the avatar, I'll give him the benefit of the doubt. Maybe he meant the Bearcat.

As I understand it, ALL the early jet engines were very sensitive to throttle changes.

[Haztoys]

Originally Posted by kool kitty89

And the F2G "Super Corsair" turned out to be a failure.

KK....What makes you say it was a "said failure"...????...I was thinking do to the time it was made...It was just not needed and never put into production...Not saying your wrong ...I know dick ...Just wondering...

[kool kitty89]

Yes and no, in the case of the 262's Jumos, once you got above ~7,000 rpm rapid throttle movements weren't much of a problem. However basicly all early turbojets had rather slow throttle response and could suffer, flameout, compressor stall, or total failure. (sometimes with combustor rupture and engine fire) This is included on the Welland, Derwent I-IV, Goblin, J31, and J33 post war these were improved somewhat.

The Jumos and BMW 003's had fuel limiting devices to prevent dumping too much fuel at once, the problem was that at low speeds the 004B's wasn't yet functioning adequately, this was greatly improved on the 004D/E.

One additional problem with the German engines was since the turbines had to be air cooled, spooling up too rapidly had an additional problem: too much fuel entered the combustion chamber before the compressor had spooled up enough to supply the necessary cooling air and the combustors and turbine could overheat, and the turbine could be softened and warped.

[kool kitty89]

The Super Corsair's performance was no better than the F4U-5, and there were considerable control/stability problems iirc.


Back to the Jets:
Early jet engines

One problem with early engines was the control of injection of fuel and
temperature. In the Junkers Jumo 004B-4 the fuel flow was partialy
determined by a Barmag gear pump whose flow depended upon both engine
RPM. There was also a centrifugal governor that was set by the
throttle and that operated a fuel bypass valve so as to modulate the
fuel flow. Should the throttle be operated too rapidly too much fuel
could be injected before engine spool up and thus leading to the engine
shedding turbine blades or combustion chamber burnouts.

The early british engines suffered from this as well though not as
badly though it can be argued that the Welland at least lacked any
performance.

The Rival BMW 003 engine had a aneroid capsule across the compressor to
provide 'throttle limiting' thus spilling excess fuel untill it had
spooled up and was much easier to handle, something that was important
for the He 162 "Volksjaeger"/"Spatz" (Peoples
Fighter/Sparrow). Throttle limiting was under development inclusive
of a temperature probe to bypass excess fuel for the Junkers engine as
well.

There's a lot of interesting info on that thread.

and: Anselm Franz and the Jumo 004

[FLYBOYJ]

Originally Posted by kool kitty89

Yes and no, in the case of the 262's Jumos, once you got above ~7,000 rpm rapid throttle movements weren't much of a problem. However basicly all early turbojets had rather slow throttle response and could suffer, flameout, compressor stall, or total failure. (sometimes with combustor rupture and engine fire) This is included on the Welland, Derwent I-IV, Goblin, J31, and J33 post war these were improved somewhat.

The Jumos and BMW 003's had fuel limiting devices to prevent dumping too much fuel at once, the problem was that at low speeds the 004B's wasn't yet functioning adequately, this was greatly improved on the 004D/E.

One additional problem with the German engines was since the turbines had to be air cooled, spooling up too rapidly had an additional problem: too much fuel entered the combustion chamber before the compressor had spooled up enough to supply the necessary cooling air and the combustors and turbine could overheat, and the turbine could be softened and warped.

Combustors? Combustion cans or chambers perhaps?

One of the problems attributing to this were the design and construction of early fuel control units which had a series of bellows and diaphragms metering the fuel to the combustion chamber. Although brilliant in their design, some of the materials used in their construction were inferior, especially rubber seals and diaphragms. These components couldn't take rapid throttle movement and would sometimes split and tear within a few hours of operations. Additionally they also did not allow an accurate metered fuel flow to the combustion chamber, again contributing to flame outs. Early fuel controls were basically mechanical computers with kerosene running through them.

Another sore spot was during the start process where careful attention had to be given to ensure the turbine inlet temperature didn't exceed it's design limits. This was sometimes difficult during start as the only control of this in early jets were the already described inferior fuel control units. As far as i know in some early jets there was a "fuel c0ck" which metered fuel during the start process and was adjusted accordingly during the start process. One had to ensure there was enough fuel getting to the combustion chamber to ensure a "light" (and avoid a hung start) but at the same time control fuel flow enough so you didn't get an over temp.

[kool kitty89]

Combustor - Wikipedia, the free encyclopedia

Combustor - Burner

[FLYBOYJ]

Originally Posted by kool kitty89

Combustor - Wikipedia, the free encyclopedia

Combustor - Burner

Ask most A&Ps what a combustor is and they'll tell you it's part of their gas barbecue.

[kool kitty89]

And I guess "burner" would be even worse in that context.
(personally I've never heard a gas barbecue or stove burner referred to as a combustor though)

And that second link is a NASA page.

I guess the "combustor" term is used fairly extensively on the technical/developmental/experimental area of turbine engines. Results: combustor

(it also seems the term is used only for gas turbine engines' combustion chambers; interestingly the wikipedia Combustion chamber - Wikipedia, the free encyclopedia page doesn't even mention gas turbines)

[FLYBOYJ]

Originally Posted by kool kitty89

And I guess "burner" would be even worse in that context.
(personally I've never heard a gas barbecue or stove burner referred to as a combustor though)

The same way most people who actually worked on jet engines won't refer to the combustion chamber, cans, etc., as a combustor.

Originally Posted by kool kitty89

And that second link is a NASA page.

I guess the "combustor" term is used fairly extensively on the technical/developmental/experimental area of turbine engines. Results: combustor

(it also seems the term is used only for gas turbine engines' combustion chambers; interestingly the wikipedia Combustion chamber - Wikipedia, the free encyclopedia page doesn't even mention gas turbines)

Only a term an engineer or Wikipedia would endure - for the most part it's a combustion chamber, combustion can(s) or burner can(s) to those who have to maintain and repair these things...

[Kruska]

Originally Posted by kool kitty89

Where did i say the Meteor Mk.I was even close to the Me 262?

The improvements to the Meteor came rater late in the war, but had there not been the problems from the horrible Rover arrangement the Meteor's development could have been nearly 2 years further along, and engine developments more so.

Hello kk89,

Off course you never said that, neither did I

You wrote the Meteor was a good a/c, and I just forwarded that IMO the Meteor of 44, 45 wasn’t a good a/c, but started to develop into such in the 50th.

The reasons that delayed the Meteor are just as valid as those regarding the 262, but nevertheless IMO the 262 was far better in 44,45 then its opposite the Meteor. Imagine the German industry would not have been so extremely limited on precious resources-metals and would have possessed a more or less intact industry such as England, the technological gap between both a/c would have been even greater in 44/45 in favor for the 262 despite its almost 2 year delay.

If Germany would not have been so lacking on the above mentioned issues, probably in 1945 the adversary of the Meteor would not have just been a 262 but also a Me P1101.

Regards
Kruska