In article ,
"eunometic" writes:
"Peter Stickney" wrote in message
...
In article ,
(Eunometic) writes:
(ArtKramr) wrote in message
...
Nuff said.
The Me 262 seems to have shot down 150 aircraft for the loss of 100 of
their own. Mostly shot up on landing or takeoff when they were even
more vulnerable to this problem than piston enginer aircraft due to
their slow throttle response. (A problem partially solved by the
better control systems on latter engines like the Jumo 004D as opposed
to jumo 004B4.)

It has little to do with throttle responce, and a lot to do with the
Thrust/Power relationship. It's a bit too late for me to type it all
in again tonight - but please do some googling in r.a.m. on the
subject.

Yes ofcourse I understand; the T/W ratio was effectively low. The aircraft
was fast because its jet powerplant didn't drop of in 'thrust' at higher
speeds like a piston engined aircraft did.

Still a proper controll system should allow the pilot to slam the throttle
back (it went backward in german aircraft apparently) and the eingine should
spool up while the control system took care of fuel and nozzle postion so
that tubine temperature stayed constant.

It still wouldn't have made any difference. The spool-up times would
have been the same nontheless, whether it was teh pilot or teh fuel
control moving the feed valve. The spool-up time has a lot more to do
with the compressor/turbine spool's mass, and the turbine's ability to
turn hot gas into torque.

It ought to be noted here that you can't just jam the throttle open in
most high-powered recips at low speeds, either. The torque reaction
(Well, Torque, P-Factor, and gyroscopic precession) will snap you
right over, and if the speed's low enough, you'll stall one wing &
spin in.

This loss rate is a dismal record; it wasn't that the 262 wasn't a
good weapons system: it was simply outnumbered and heavily targeted by
the allies and also and quite a few losses were experienced on the
first missions due to the tactic of slowing down to take aim. It
wasn't untill tactics were worked out to solve this that effectiveness
improved.

And placed into service long before it should have been.

Erhard Milch wanted it on service by 1943. This was one of the few weapons
that could have changed the course of the war if it entered service early
enough.

What Milch wanted, and what teh German aircraft industry could
deliver, were two very different things. The German jet engines took
an incredibly long time to go from prototypes to something tht could
be marginally reliable enough to be placed on an airplane. Some of
this was due to the shortage of what would now be called Strategic
Materials, but a lot of it was trying to sort out the compressor,
combustor, and turbine aerodynamics. The materiels problems weren't
new - they'd been a factor in German industry since the mid 1930s.
The other problems were the sort of thig that happen when you're
trying to do R&D on something that's totally new. You don't know what
problems are going to pop up, and how long it'll take to fix them.
Of course, once they got the engines sorted out, they would have to
deal with the airframe. And they had big problems there, as well, suc
as the blanketing of the tailplane due to the choice of a conventional
landing gear. That required a redesigned wing structure, and a new
fuselage. The in-service date slipped nearly a year, despite the high
priority of the work being performed, and there was nothing that could
be done about it.


Some
problems, like poor asymmetric handling at low speeds (One Engine out)
were endemic to the design. But there were other problems - high
speed snaking, and some rather ugly transonic behavior that should
have been resolved before service pilots were turned loose in it.

They likely would have eventualy debugged these; both the Meteor and F80 had
problems upon entry into servive but I agree the Germans jumped this
aircraft into service more prematurly than the allies for obvious reaons
while the me 109 had to soldier on.

The appearence of the aircraft looks like it would snake however. It is my
understanding that the original location of the engines was mounted next to
the fuesleage under the wings and that this was changed when the dimensions
of the engine increased and presumably turbulence issues arose. There were
versions using the He S11 engine in this position (models availble as is to
be expected) Presumbly the fact that thrust was closer to the centerline
would have improved stability.

Also I recall a Quantas engineer telling me that the Beoing 707 had a
snaking motion and a damper was fitted to the trim tab on the rudder that on
the basis of an accelerometer (or possible gyro?) counter acted any snaking.
It was I believe an all mechanical/hydraulic system.

The snaking had to do more with flow separation on the vertical fin &
rudder, and the length of the nose destabilizing the airplane in yaw,
than anything else. It was a problem, to some degree or another, with
just about all of the early jets.
As for the 707, That wan't snaking, that ws Dutch Roll, and is a
result of the dihedral effect of a moderatly-highly swept wing. They
also added a ventral fin under the aft section of teh tailcone, as
well. It first cropped up on the B-47, BTW.


The Me 262 Pilot's Handbook has about 3 pages of handling
limitations. The F-80A Pilot's handbook has 2 flight limit entries.

I may have seen this handbook but I don't know if we are talking the same
thing. Most of the limitations from what I can see relate to engine
handling of the jumo 004B1 and Jumo 004B4. This was mostly caused by the
crude fuel delivery and metering system system (the BMW003 was better and
the Jumo 004D matched it). Also the use of J2 Diesel fuel (or K2 heavy fuel
in an emergency) for reasons of safety, economy and its ease of synthesis
meant that the engine was started on a parafinic gasoline and then switched
over to the J2 again complicating starting. finally starting consisted of a
small 2 stroke motor which itself had to be started and then only when the
air was thick enough at lower altitides. The lack of duples injectors mad
high altitude flameout easy and relights hard.

Better control systems and duplex injectors helped solve all of these so the
restriction may have enventually disappeared. As I understand Helmuth
Schelp began to favour a central generating faciltiy and individual electric
starters possibly to eovercome this and also for the larger jets like the
8000llb thrust BMW 009-016 a gas turbine starter so that a single fuel could
be used.

Many of teh entries are engine handling entries, certainly. But by
the same token, the U.S. and Brit jets don't have most of these
limitations. Or the limitations on flight. (No negative G flights,
etc.) Soem of this is due to the relative maturity of the
technologies - The P-80 and Meteor III wre using second-generation jet
engines, developed wit the lessons of the first engines in mind, and
already in production before the Germans had soerted out their first
generation jets. Part of that is systems design. The Me 262 should
have had better fuel, electric, pleumatic, adn hydraulic system than
it did.



You know, it's rather interesting that for all the work on high-speed
aerodynamics that the Germans actually did perform, they never seemed
to be able to translate it into the aircraft they built.

Lets face it they never got much outside the Me 109 in service and its was
to old to grow gracefully anymore though I presume the Ta 152C and Ta 152H
had good high speed handling.

109s could, and did, have compressibility problems. The Germans lost
a Rechlin Test Pilot in 1937-38 during high-speed dive tests, for
example. Fw 190-derived shapes also had problems. But there wasn't
much effort put into exploring these issues, and dealing with them.
As for the Fw190D and Ta-152 (Basically the same shape) Not really no.
No better than a Mustang, and certainly not as well as a Spitfire.

The German
Aviation Military/Industrial Complex's solution to
compressibility/controllability problems in their airplanes was to put
a Big Red "Thou Shalt Not..." notice in the Pilot's Handbook. Compare
this to the work done in the U.S and Britain to sort out the
transonic problems that were occurring - the developmetn of the DIve
Recovery Flap (Which isn't a Speed Brake), improved control surface
geometries, and, for that matter, the inclusion of Speed
Brakes.

Was this flap ever used?

Absolutely. It was a standard fit on late model P-38s, P-47s, and F8F
Bearcats that I know of. The P-51 didn't need one, and the jets had
Speed Brakes that could not only slow them below the critical speeds,
but could be rigged to give a nose-up pitching mement to help dive
recovery.

One of the nastier "Own Goal" Amicide incidents WW II was when a
Canadian Spitfire pilot mistook the C-54 carrying the first 200 Dive
Recovery Flap kits for ETO-based P-38s for an Fw 200 Kondor, and shot
it down.


In technolgy the Germans and allies were closely matched. Both sides
produced major breakthroughs and both sides had areas where they fell
embarrasingly far behined.

The Germans were perhaps forced to focus on Break throughs because
resources were massively against them after 42 but in the end the odds
were against them. I do suspect that the breakthroughs would have
broken up the superiority of the allies in some areas. Jet aircraft
gave them a fresh start that would have equalised them where the
allies ahd piston engined superiority in quantity and quality. Sure
the allies would also have had jets but their existing technolgy would
have had its value wiped out and would have made useless almost all
piston engined aircraft: B26,A26,P47, B17,B24,B25 etc but they never
got enough of their jets going in time.

It's not that simple. There were a lot of factors - the most telling
of which were evident in 1936, when the Luftwaffe, and the other
German Armed Forces, cut back on armament production because they
didn't have enough raw materiels to use the factory capacity they
already had.
One of the other things they should have done was build up a better
training organization. A big limit was the lack of properly skilled
pilots. By late 1944, there weren't enough fully capable pilots to
make a differece, even if they were flying Mr. Arndt's Disks and
herding around Reptilicus. There's no point in making jet airplanes
if you have nobody who can fly them.

They weren't intending to fight a long war of attrition which they would
eventually loose I suppose. This training issue, why was it mucked up?
They must have had their reasons? Or were those with sensible arguments
suppresed?

Call it a blind spot on the part of the German General Staff. (It was
around long before Hitler, and pervaded all of the Germans' Strategic
Thinking from 1871 on.)
They believed well and truly that they were the Jedi Knights, so
expert in, and devoted to the Art of War that nobody eith would stand
against them, or if they did, could stand against them for long.

The lesson that they learned from World War I was that they didn't try
hard enough, and that they didn't get the total support from teh
civilian side of the Kaiser's Government that they needed. (The whole
"Stab in the back thing. Of course, teh Civilians felt the same way,
which left a political climate ripe for a replay of teh War, to show
what they could really do. Stuff like Moltke the Younger's inability
to be, say, flexible enough to actaully follow the Kaiser's Orders to
not mobilize against France, and when mobilized to not automatically
attack France, (Through a neutral country) allowing the situation to
cool off, was sept under the rug.)

So, they got surprised when the war continued. They had no plans for
an extended conflict, for such a thing was unthinkable.
There were also significant shortfalls in the numbers of Flight
Instructors, and non-fighter or bomber pilots. This was a
double-edged blade (More like a toggle-head harpoon, actually) in the
trainig effort. When it became necessary to launch the airborne
invasion of Crete, and, later, to attempt the resupply of Stalingrad
and Tunisia, they stripped the flight schools of instructors to
provide the transport pilots. They suffered catastrophic losses in
these campaigns, and the training effort never recovered.
The policy of leaving pilots in units for the duration didn't help,
either. Combat pilots were never able to get any (relative) repite,
and pass the lessons that they'd learned on to the new trainees.
Instructors knew that they'd be instructing for their entire careers,
unless they got drafted off to be thrown into another set of failures.
That setup doesn't produce good pilots.
When you add in the fact that they had no training frounds that, after
mid 1943 weren't vulnerable to attack by Allied fighters, and teh
uncooperative German weather, there was no way that they'd be able to
produce anything like the number of Stick Actuators that they'd need.

I don't like the "Allies Invented Everyting" nor do I like the
"Germans Invented Everyting" attitude. Anyone who knows how
technology advances should realise what one man can do another will
replicate almost immediatly. One of the mistakes of the Germans in
the Radar war was to put so much secrecy on their radar vulnerability
that they failed to develop effective countermeasurews to windows
jamming becuase the requise people weren't involved.
It should have been obvious that the British, who were behined in
Radar at the time would soon catch up.

That is a rather good example of the German's arrogance about their
own technology, and their "Mirror-Imaging" of how a particular
technology would be used. In 1939, and 1940 the Germans had the best
high-frequency radar around. Their main thrust for it, however, was
to use it to bulwark existing systems, specifically Antiaircraft and
Naval Fire Control. And they did this well.Once they'd figured out
that the long-wave pulsed signals that they were receiving was some
sort of radar, they absolutely knew that they were far ahead of teh
British, and didn't need to worry about it. What they missed,
however, was that those primitive, inaccurate long-wave radars were
part of an integrated Cammand and Control system that allowed RAF
Fighter Command to concentrate their forces with an efficency not seen
in aerial warfare before that time.
That same blindness - that belief that the German stuff was superior
because it was German, effected them in all areas.

God bring me an arrogant enemy. (to be fair there are pleny of people on
these NGs who would underestimate an enemy)

An Integrated air defense system makes sense for the British on their
island. For the landlocked Germans, who had no channel, a philosophy of
avoiding a war of attrition and winning the frist battles so as to avoid
fighting on German soil prevailed. Very little was devoted to defense it
was thought best to devote it to attack and support of the Army and this
probably starved the development of such systems eg IFF. Also who would
run it? Kammhuber was regarded with suspicion for his large line of radar
defese stations.

Just so.


The over confidence was there, Georings rash statements prove it, but there
was more behined it I think.

As you said before, it was a reflection of their philosophy. They wer
the War Gods, and nobody could stand before them, so they didn't need
to work on defence.

Alexander the Great however with 50,000 men once defeated Darius's
army of 2-3 million with boldness and clever tactics.

Uhm, I don't think that ther were 2-3 million people in the entire
Persian Empire. Subsistance farming doesn't give you that sort of a
reserve.

It wasn't subsistance farming: they had huge cities.

A huge city then would have been about 30-40,000 people.
Even allowing for the exaggeration that occurs in the contemporary
accounts, that number is rediculaous. Armies travelled on their
stomachs, especially then, foraging for their food as they went. Even
if you had that number of troops, you couldn't feed them.

And think about it - how do you bring 50,000 men, with bows, spears &
swords, into contact with that large a number? You don't. If such
numbers were true, Darius would have angaved Alexander's army with a
paltry 250,000 or so troops, holding it in place (Even if the Greeks
slice them to fishbait) while the other 2,750,000 guys go take their
enemie's homelands.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster