WAllied jet aircraft timetable improvement

[GrauGeist]

The improved P-59B only reached a max. speed of 435mph, 100mph slower than the Me262A-1a, while their empty weights were comparable.
The Airacomet suffered from "snaking" like the early Meteors, but it's short-comings fall on the engines and the fact that Larry had no idea of the thrust value and pretty much designed the airframe as if it were a piston-powered ship (the weight of the M10 37mm cannon didn't help, either).
The J31 was simply not powerful enough - now if they had gone with the J33, then the P-59A may have had a chance...

 

[special ed]

Bell wasn't given dimensions and only approximate weight of the engines.

 

[GrauGeist]

It also didn't help that the Army insisted on stuffing the 37mm cannon in the nose.
That's over 200 pounds (not including ammo) that the airframe did not need.

 

[nuuumannn]

I figured on just skipping a bunch of lesser players and get right to it.

Yup, understand; I was adding historical context. It sounds plausible. Whittle contacted Arnold (I think) first, who got the ball rolling stateside. The jet engine was part of an information and technology exchange between the two countries. It's not implausible, but I think starting in Britain is gonna take priority if we want the timeline to go back a few steps.

Here's a wee summary of what happened in reality. Whittle met with George Carter of Gloster in April 1939 and despite Carter being Whittle's senior by 18 years the two got on really well. Carter got a team of guys together pretty quickly and had drawings made swiftly. The whole lot left the busyness (business?) of the Gloster hangars at Brockworth behind and the two prototype E.28/39s were built in non-descript garages in the suburbs of Cheltenham, out of the gaze of prying eyes.

On 15 May 1941, Gloster's Chief Test Pilot, Flight Lieutenant Gerry Sayer flew the aircraft under jet power for the first time from RAF Cranwell, near Sleaford in Lincolnshire, in a flight lasting 17 minutes.

The prototype first got airborne on 8 April 1941 during fast taxi trials at Brockworth on three separate occasions and these are unofficially recognised as Britain's first jet flight, but the 'official' first flight was at Cranwell. It all happened quite quickly, from Whittle's first meeting with Carter, the production of drawings, the design and building of two prototypes to its official first unveiling and flight at Cranwell in May 1941.

 

[nuuumannn]

The improved P-59B only reached a max. speed of 435mph, 100mph slower than the Me262A-1a, while their empty weights were comparable.
The Airacomet suffered from "snaking" like the early Meteors, but it's short-comings fall on the engines and the fact that Larry had no idea of the thrust value and pretty much designed the airframe as if it were a piston-powered ship (the weight of the M10 37mm cannon didn't help, either).
The J31 was simply not powerful enough - now if they had gone with the J33, then the P-59A may have had a chance...

It would have been interesting if the order to build America's first jet went to Lockheed instead of Bell... That's probably the better way of saving time in getting jet fighters into service faster from the US side of things, as has been suggested here earlier.

 

[SaparotRob]

It would have been interesting if the order to build America's first jet went to Lockheed instead of Bell... That's probably the better way of saving time in getting jet fighters into service faster from the US side of things, as has been suggested here earlier.

Any thoughts about going with the L-133 instead of the Lightning? No, I guess not. Bird in the hand, as it were.

 

[pbehn]

Fire up the Time Machine and go back to 1928. Give Whittle some money and access to a good engineering company. Make sure Whittle employs a young Adrian Lombard and let them build jet engines. By 1939 a decent working prototype can be air tested in a Wellington or similar.

Give him a passport and a ticket to the USA

 

[wuzak]

Fire up the Time Machine and go back to 1928. Give Whittle some money and access to a good engineering company. Make sure Whittle employs a young Adrian Lombard and let them build jet engines. By 1939 a decent working prototype can be air tested in a Wellington or similar.

I think the key is to go back an convince AA Griffith that jet engines do work. Then when he reviewed Whittle's calculations he would not have dismissed Whittle's engine as impractical and his own work on axial compressor turbines may have been directed towards jet engines rather than turboprops, potentially getting an axial flow turbojet to production status during the war.

With a positive review from Griffith the Air Ministry is more likely to financially back Whittle's developments and provide connections to engine manufacturers (like Rolls-Royce) earlier.

 

[wuzak]

Any thoughts about going with the L-133 instead of the Lightning? No, I guess not. Bird in the hand, as it were.

One had engines that worked.

And the other had engines that were in the earliest stages of development.

Which would you choose?

 

[GrauGeist]

The Lockheed L-133 looks fantastic, but it would require engines that did not exist in 1939/40 and bears a strong resemblance to the F-104 concept - which was clearly not a fighter in the 1940's sense.

If we're going to fire up Mr. Peabody's "way back" machine, then invite Von Ohain to work for General Electric before Heinkel grabbed him up...

 

[wuzak]

Yup, understand; I was adding historical context. It sounds plausible. Whittle contacted Arnold (I think) first, who got the ball rolling stateside. The jet engine was part of an information and technology exchange between the two countries. It's not implausible, but I think starting in Britain is gonna take priority if we want the timeline to go back a few steps.

Not sure that Whittle had any contact with Arnold.

The technology exchange was the Tizard Mission, which included plans for Whittle's engine as well as a cavity magnetron.

 

[SaparotRob]

One had engines that worked.

And the other had engines that were in the earliest stages of development.

Which would you choose?

As I was posing that thought, I answered my own question. Pretty much along those lines. I just don't know how to "unreply".

 

[GrauGeist]

As I was posing that thought, I answered my own question. Pretty much along those lines. I just don't know how to "unreply".

You can't undo a reply - you can edit the content, however.

Otherwise, the reply is there 'til the end of time!

 

[fastmongrel]

It's interesting that when Whittle, Obtain and Griffith were talking baby steps towards the gas turbine, powered flight was only a generation old. Turbines and internal combustion not much older.

Yet even though the technology of aviation was so new there was a lot of inertia to overcome for new ideas. When Whittle started his theoretical work aircraft almost universally were wooden with 2 wings and lots of wires. It must have been like Artificial intelligence is to us today. Exotic and a bit scary.

 

[fastmongrel]

You can't undo a reply - you can edit the content, however.

Otherwise, the reply is there 'til the end of time!

I find the stupider and more embarrassing the reply the longer it's lifespan.

 

[SaparotRob]

One had engines that worked.

And the other had engines that were in the earliest stages of development.

Which would you choose?

I'm surprised you didn't mention the lack of range that might keep the L-133 (super P-59?) from being as effective in the PTO as the P-38. That's what I thought as our "what if" planes always seem to have working engines.

 

[GrauGeist]

*technically* speaking, the L-133 would have been the "super P-80", as it was a Lockheed design.
The XP-83 might be a super version of the P-59A/B.

 

[Koopernic]

For the British:
1 Focus on Axial Flow Jet engines. The Secret of British success is the nimonic alloy and fir tree roots of the turbine blades not centrifugal compressors. The large diameter of the 2000lb thrust British engines created so many airframe integration issues at transonic speeds that the Meteor was greatly delayed. The Metropolitan-Vickers F.2/Beryl needs to be promoted.
2 If the British are not going to make Axial engines they need to make 4000lb thrust engines so they can hide their drag inside an airframe. In fact the nene was ready before the derwent IV
3 Build supersonic wind tunnels so they understand transonic and supersonic effects. The Germans revealed all at Musolinis Volta conference.

For the Americans:
1 Get NACA involved. Decision to not involve NACA meant the Bell XP59 was bound to be a failure because Bell lacked the knowledge to pick the correct wing profile.
Over at NACA Eastman Jacobs was developing a motor jet 550mph a transonic aircraft design called Jakes Jeep that used the excellent new NACA laminar profiles. Jakes Jeep became the Bell X-1 (ironically) but (Happ Arnold?) kept NACA out of the loop making the XP59 a lemon.
2 What is going on? The US has the alloys (Stellite/Hastelloy) and they have developed turbosuperchargers but can't put 2 & 2 together. Sanford Moss face palmed himself.
3 US of course realised British engines were too small which lead to the development of the nene.
4 Why does Lockheed J37/L1000 progress so slowly?

Note the Germans, British and US all shared the same problems.

The Germans should have adapted their piston fuel injections systems to meter fuel into their jet engines. It merely required pressure/flow measurement ahead of the jets combustion chamber instead of the inlet manifold. This in fact applies to all combatants. Fuel metering was poorly done by all.

 

[Zipper730]

I was thinking the problems we had were several...

1. NACA seemed mostly interested in speeds around 550 mph, and might not have seemed to have registered the degree to which they were inching up on transonic phenomena and the problems this would pose.
   • NACA had already developed wind-tunnels capable of producing supersonic speeds by the late 1920's (they reason they weren't useful was because, at best, the shockwave would bounce off the walls and invalidate everything downstream).
   • At some point in the 1930's (I think) there was a test done on an airplane model (DC-3?) as an intellectual exercise whereby the airflow was pushed up to speeds where one could see where the airflow would go transonic first: This was actually a useful exercise as it helped show what variables will lead to compressibility onset.
2. NACA seemed to have hitched much of their ride to high-speed flight on minimizing cooling drag and developing high-speed propeller aircraft, with the little bit left to Caproni-Campini-type motorjets.
   • Their motivations appeared to have been affected by the following
     • Edgar Buckingham's 1923 report which evaluated the idea of using a piston engine that would use all its exhaust to produce thrust, save a small amount for the supercharging systems. There were numerous flaws in the study, which seem as follows...
       • Buckingham's own statements indicated that there would be little to no systems aimed at maximizing the exhaust or inlet efficiency which would have eked more performance out of the design than his proposal described.
       • He factored in a presumed exhaust velocity of 5280 f/s, something that was well beyond what would be needed for some jet-designs (i.e. a gas-turbines).
       • He assumed a compression ratio of 15 atm would be needed as a bare minimum, and a point of diminishing returns would be reached at around 30 atm.
       • While he did note that ram compression would increase thrust at higher speeds, he only factored in speeds up to 250 miles per hour, and would produce efficiency figures approximately 25% that of a piston driven airplane and would be unsuitable to propulsion systems. This was something that ended up often being used as a cugdel to beat down anybody who proposed such a system.
       • To NACA's credit: There was a work order put in to evaluate such a system for higher speeds (i.e. around 550 mph), which appears to have been undertaken by Eastman N. Jacobs. Unfortunately, it was cancelled for reasons I'm unaware.
     • The Caproni-Campini jet was seen as having advantages at lower speeds as, it was effectively a ducted propeller. With cooling drag reduced sufficiently that it was felt to be acceptable (though, possibly not optimal) to a regular propeller-driven aircraft with the burner off. Of course, there were obvious flaws in this reasoning...
       • The speeds where the engine would be at its best would actually see higher fuel consumption than a gas-turbine because of the fact that, as I understand it: The propeller probably produced a lower pressure ratio than a properly designed centrifugal flow impeller and, you need combustion to drive the propeller/impeller, and combustion to produce the exhaust for high speed flight.
     • Gas turbines were felt to have numerous problems, mostly related to weight: It seemed that they were seen as being excessively heavy. With knowledge available based on turbosuperchargers, I am surprised nobody realized that industrial based gas-turbines were heavy only because they were huge and there was no need for them to be lightweight (there could have been the possible concern of scaling producing weight problems).

While Koopernick was banned: I have been somewhat fascinated by the L-1000/XJ37 & the L-133 fighter it was to power. It had two bright-sides.

1. It was an American built design
2. It produced a good amount of power on paper

It was, however highly overly complicated (both the aircraft and engine): I think I have some information on the engine that I found somewhere.

 

[SaparotRob]

Wasn't Kelly Johnson and his crew working on an after burner as well?