German 'jet program' - how to do it? (1 Viewer)

[Acheron]

I would suspect that focusing on one aircraft would do little to help the Luftwaffe, from what I gathered from other posters, the main issue were jet-engines in general, especially their unreliability and short-life spans. It was a brand new technology that needed its kinks hammered out and that simply takes time.

Though by that logic, an earlier effort could make quite the difference. Now I wonder, if the jet engine had attracted a high-ranking patron, like the dive bomber did previously, could development been considerably sped up? How much development work did happen with this new technology historically and how much would realistically have happened if higher-ups had been excited about it?

 

[GrauGeist]

Most of the "higher ups" that yawned at the He178 and again, at the He280, were old-school WWI pilots with a narrow view when it came to new technology.

One of the key features of the HeS jet engines, is that they could operate on Kerosene, which left the much needed gasoline to the piston powered aircraft.

 

[Shortround6]

While the ability to run on Kerosene was a useful capability it wasn't a panacea for the Luftwaffe.

Kerosene was better in supply than high octane aviation fuel but it was by no means unlimited.

The Jets also used fair amount of Kerosene per flight.

The Germans were not going to be able to field hundreds (or thousands) of jet bombers like they did piston powered planes in 1940/41.

 

[tomo pauk]

The Jets also used fair amount of Kerosene per flight.

Fair? More as if they were dumping it overboard It took about 3 times more of any fuel in a jet-powered aircaft to equal the range of a similar piston-engine powered aircraft of similar size and weight. Me 262 flew with 2400-2600 L in internal tanks.

Huge consumption + low availability of engines (themselves with short TBO) = 2-engined jet fighters were not a cure for LW woes.

 

[Dimlee]

Hey, my favourite Ar 234 was built in hundreds!
OK, just two of them.

 

[tomo pauk]

Anyway - He 162 with longer, still straight wings at right vs. the 'normal' one at the left:

 

[Shortround6]

The jets might be a useful addition for some roles but it needs to pretty short range.
More jets would be better for defensive missions, but not for offensive missions.

Not just German jets but British and American jets were pretty dismal ranged planes at low level.
The Ar 234 held over 800 Imp gal gallons in the internal fuel. But at low level it have only 500-600 miles of range (not radius) and that is clean and not with one or two bombs.
Granted it is very difficult to shoot down.

At 25,000 to 30,000ft the range could be around double?

 

[tomo pauk]

The jets might be a useful addition for some roles but it needs to pretty short range.
More jets would be better for defensive missions, but not for offensive missions.

Jets were dearly needed for defensive missions, short range ones.

At 25,000 to 30,000ft the range could be around double?

Two Jumo 004 were using, depending on setting, 2900-4550 L/h at 2000 m. AT 8000m, 1390-2110 L/h; per manual for Me 262.

 

[Thumpalumpacus]

I think that while earlier German development of jet tach could have prolonged the war somewhat, the fact that it was up against three huge economies on two fronts meant that there was no easy answer.

 

[GrauGeist]

The Axis still would have failed, but if the Luftwaffe had jets operational and in force while they still held air superiority in the early stage of the war, it would have forced the Allies to up their game.

This in turn would have changed the face of the European air war and today, we wouldn't be discussing the fastest late-war piston fighter, but the fastest late-war jet.

The U.S. had several jet (and mixed power) projects (P-81, P-83, F15C, BTD-2, FD, FR and the B-42) in the works before war's end (not including the P-59 and P-80) and Britain had the Vampire.

So things would gave gotten quite interesting...

 

[Shortround6]

My personal problem is that the British and Americans struggled to solutions to jet problems through 1947 and 1948.
Like the Martin XB-48 that first flew in June of 1947 and went through 14 engines in 44 flights.

Some of the early J-35s and J-47s were good for 7 1/2 hours before inspected and another 7 1/2 hours before the engines were pulled for overhaul. Things got lot better (much much better) later on but it just a bit too good for the Germans to fix of their problems with a shooting war, materials shortages and so on and doing it 2-4 years before the allies can solve the problems.

 

[GrauGeist]

The He178 first flew a month before Poland was invaded - if (and this is a huge IF), the RLM had an epiphany and/or Der Fuhrer made it clear that the jet program was a priority, then the industry could have made progress far and beyond what it did.
The airframe development would have moved from the "get to it when we have time" stage to actual time and effort applied, the engine program would have changed from a political tool to a serious "make it happen" setting.
All at a time when resources were still at hand, the infrastructure was intact and factories weren't being pounded day and night.

 

[FLYBOYJ]

And to throw another "what if" in there - I think Germany "would have" had an easier time getting a turbine engine operational if they "would have" went with a centrifugal compressor. Smaller, simpler and less parts.

 

[GrauGeist]

The He280 flew remarkably well with it's HeS8 engines, even though it was intended to ultimately be equipped with the HeS30.

It's interesting that the HeS30 weighed less than 900 pounds, but produced a thrust to weight ratio of 2.20 while the Jumo 004 weighed close to 1,600 pounds and only produced a thrust to weight ratio of only 1.25

 

[tomo pauk]

And to throw another "what if" in there - I think Germany "would have" had an easier time getting a turbine engine operational if they "would have" went with a centrifugal compressor. Smaller, simpler and less parts.

Also far less weight.
HeS engines used centrifugal compressors, however they never became 'mainstream'.

 

[tomo pauk]

Some of the early J-35s and J-47s were good for 7 1/2 hours before inspected and another 7 1/2 hours before the engines were pulled for overhaul. Things got lot better (much much better) later on but it just a bit too good for the Germans to fix of their problems with a shooting war, materials shortages and so on and doing it 2-4 years before the allies can solve the problems.

Look at that from German perspective.
They need to find a way to reliably out-perform the best Anglo-Americans can throw at them between the fall of Italy and Overlord. Grafting a DB 603A or Jumo 213A on a Fw 190 does not solve that (even before we start talking about DB 603A having major reliability problems even in 1944, or that Jumo 213A is not available before Big Week or thereabout). The 2-stage versions of these engines are just been mooted.
So the only way available for them is to make jet-powered fighters, imperfect as they were. Looking at these US figures, the early German jet engines are bed of roses.

Piston-engined fighters are/were still useful on the Eastern front.

 

[Acheron]

Question though: I know the Me 262 mostly as an, admittedly very superb, bomber destroyer. I assume it's speed allowed it to get past the escorts and after the bombers?

1: To my knowledge, the M 262 appeared only in limited numbers and thus had a limited impact. More Me 262 = more impact BUT also more effort on the allied side to counter it. Assuming allied jet development to be too far behind, at least for the moment, what could, excellent, piston-enginged fighters do against it? Could the speed advantage for example have been negated by the pistoners flying high and diving after the Me 262? My understanding is that while it was fast, it wasn't very maneuverable.

2: How good would the Me 262 have been at shooting down enemy fighters? Assuming an earlier appearance in substantial numbers, it would surely still be outnumbered but maybe not to extremely so. Still, could the Me 262 just have used its superior speed to go after and waste an enemy an be away before its buddies shoot it down in turn? I am asking because evading enemy fighters to go after their bombers is all well and good, but if it cannot actually go after their fighters, it cannot protect its own bombers in turn.

 

[tomo pauk]

1: To my knowledge, the M 262 appeared only in limited numbers and thus had a limited impact. More Me 262 = more impact BUT also more effort on the allied side to counter it. Assuming allied jet development to be too far behind, at least for the moment, what could, excellent, piston-enginged fighters do against it? Could the speed advantage for example have been negated by the pistoners flying high and diving after the Me 262? My understanding is that while it was fast, it wasn't very maneuverable.

Have all the Western fighters have useful internal fuel tankage + drop tanks, so they can go aggresive over better part of what was pre-war Germany (and by default over Belgium, Netherlands and France). Mass the fighters. 'Visit' the LW air bases often. Dive-bomb air bases with P-47s from high altitude.
Problems for the Me 262 were it's low availability, short range, low-speed capabilities - RAF & USAF can use that to the advantage.

2: How good would the Me 262 have been at shooting down enemy fighters? Assuming an earlier appearance in substantial numbers, it would surely still be outnumbered but maybe not to extremely so. Still, could the Me 262 just have used its superior speed to go after and waste an enemy an be away before its buddies shoot it down in turn? I am asking because evading enemy fighters to go after their bombers is all well and good, but if it cannot actually go after their fighters, it cannot protect its own bombers in turn.

Boom and zoom - basically, it is a situation similar to that of P-51D vs. Zero or Oscar scenario.

 

[gruad]

The Jet fighter has to enter service a year earlier to stand a chance of making day superiority over Germany and retaining enough skilled pilots.

A single engined centrifugal compressor design with proper alloys is probably best for this something like the He 162.

The result might be the US bombing at night where this plane would not make a great nightfighter.

 

[nuuumannn]

The Axis still would have failed, but if the Luftwaffe had jets operational and in force while they still held air superiority in the early stage of the war, it would have forced the Allies to up their game.

This in turn would have changed the face of the European air war and today, we wouldn't be discussing the fastest late-war piston fighter, but the fastest late-war jet.

The U.S. had several jet (and mixed power) projects (P-81, P-83, F15C, BTD-2, FD, FR and the B-42) in the works before war's end (not including the P-59 and P-80) and Britain had the Vampire.

So things would gave gotten quite interesting...

I agree. British intelligence became aware that the Germans were investigating jet powered fighters in 1940 and even the name "He 280" appeared in intel supplied to the British that year. The Brits kept a close eye on German jet development, the Me 163 was the first "Jet" to be photographed and identified as such, in prototype form in 1942. This caused quite a bit of a stir and a year later following the discovery of the Me 262 in recon images the Brits began to fear masses of German jets in service. One 1943 intelligence summary quoted around 1,000 jet fighters becoming available to the Germans could cause a real problem, but thankfully the reality of the situation a year later meant that there were never anywhere near that number operational. The net result was the acceleration of Allied jet development and bombing of production facilities - the Jumo facility was bombed in 1944 causing a severe shortage of jet engines to the front.

Had the Germans developed jets sooner, the same thing would have happened, accelerated jet R&D and bombing of known production facilities.