British Jet for BOB?

[bigZ]

Please raise a glass to the man who helped make the world a smaller place. On July of this year it was a centuary since Frank Whittle's birth. Over here he is very much a forgotten genius. Their is no airport named after him and even his original jet engine is not displayed as befits it status.

In fact history is being re-written. Most acknowledge him as the co-founder of the jet engine with Hans von Ohain. In fact although Hans von Ohain denied all knowledge of Whittle's design. His assistant readily admitted that copies of Whittle's patent formed the basis of the design and copies of it where available to all technical colleges throughout Germany.

 

[Sgt. Pappy]

heh I think the British are a little too caught up with the Spitfire to be concerned about the underrated Whittle.

He deserves much credit for his work.

 

[Soren]

As much as I repect Whittle for his work I don't believe Ohain violated any patents, he did after-all assist Whittle in his work. Ohain was also abit more futuristic with his designs, as illustrated with the HeS engines.

The worlds first Turbo-Jet aircraft, the He-178:

 

[red admiral]

I'm not quite sure why Von Ohain is credited with being the co-inventor of the jet engine when he received the full plans of Whittle's engine of 1930 from the German embassy in London. Von Ohain's engine is basically identical to Whittle's patent apart from the radial outflow turbine, adopted for heat considerations.

Considering that Whittle also invented a number of turbofans, reheat and the turbodrill he is far too much overlooked. The Whittle design turbojet went from 850lbf to 2500lbf in the W.2/700 with very little change in size and weight. For the M.52, the W.2/700 was to be developed into a duct-burning turbofan producing over 5000lbf. Not bad for something built in an outhouse on a shoestring.

 

[delcyros]

Frank Whittle deserves more credit. While it is true that v. Ohain thought about comparable lines quite as early, it should be mentioned that his later wors greatly benefitted from Whittle´s patent. The jet engines he developed are no copies but they were helped more than most are willing to accept.

 

[bigZ]

As much as I repect Whittle for his work I don't believe Ohain violated any patents, he did after-all assist Whittle in his work. Ohain was also abit more futuristic with his designs, as illustrated with the HeS engines.

The worlds first Turbo-Jet aircraft, the He-178:

No Ohain didn't violate any patenets as Whittle couldnt afford the £5 to renew them in 1935. Perhaps if the RAF had taken some intrest we might have had a jet in service much earlier and perhaps the Germans might had not had time to get theirs?

 

[magnocain]

Didnt Whittle also do the dam busters and the grandslam/tallboy?

 

[Gnomey]

That was Barnes-Wallis. Whittle is completely under recognised here, most people wouldn't know who he was which is a shame considering what he invented. Certainly deserves more recognition + the engine should be displayed in either the IWM (Duxford or London) or the RAF museum at the least.

 

[Graeme]

Perhaps if the RAF had taken some intrest we might have had a jet in service much earlier and perhaps the Germans might had not had time to get theirs?

Sir Frank Whittle was convinced that if he had been given adequate Government backing and the development resources of Rolls-Royce, the RAF "could" have had Meteors in 1942. He was also a firm believer that the Rolls-Royce was "superior in almost every respect to the Junkers Jumo 004."

 

[bigZ]

Sir Frank Whittle was convinced that if he had been given adequate Government backing and the development resources of Rolls-Royce, the RAF "could" have had Meteors in 1942. He was also a firm believer that the Rolls-Royce was "superior in almost every respect to the Junkers Jumo 004."

The Russians agreed with him, and used a Russian version of the RR Nene rather than any German alternative for the Mig 15.

 

[johnbr]

Yes it a shame that such a great man as him is all but forgotten.For he chained are world for ever.

 

[kool kitty89]

Ohain's designs were quite a bit different than Whittle's and if you look at Whittle's patent, it was far different than Whittles final design. Whittle's patent design used 2 axial impellers followed by a single-sided centrifugal compressor-Ohain may have borrowed the axial impeller idea but was still quite different, Whittle dropped the axial stages and switched to a 2-sided dual-intake centrifugal compressor.

Probably the biggest difference was the turbines and combustors. Whittle had always used flame-cans and axial-flow turbines, while Ohain had used annular combustors and radial-inflow turbines (Ohain's choice was troublesome for a production design since the combustor was difficult to service and assemble and the turbine was too large to use turbine alloys practically, so steel was a must, and what's worse is that this turbine can't be aircooled affectively)

Another thing to note is that Whittle was ahead in combustor design and fuel type. His W.U. engine burned Diesel fuel, while the HeS 1 (which had run just days earlier) could only burn Hydrogen gas. Even Ohain's first flight-engine the HeS-2 (same as the HeS-3 but only used Hydrogen) had to burn Hydrogen and was only used intrim for the HeS-3 to meet deadlines.

However, one thing Ohain has said is that, while he was aware of other efforts (he discovered only when he was denied a patent in 1930) he didn't think they were being pursued (particularly the Swedish ones he knew weren't being pursued) and he though Whittle's patent design was unstable.(Which in all likelihood, it was, though we don't know since it never progressed past a patent sketch)
See: The Jet Race and the Second World War - Google Book Search

Besides this Ohain had said that He preferred to come up with his own ideas and then see what others had done. Indeed, when Whittle Had first seen Ohain's design he was angered and thought Ohain had copied him and was claiming it as his own. Later Whittle had examined it more closely, and after speaking with Ohain, Whittle was convinced that the designs were both original.

Also the folding used on the Whittle's engine was quite different than that of the HeS-3b and HeS-6. This folding-forward of the combutoin chamber over the compressor was in fact a suggestion by Max Hahn, a suggestion Ohain encouraged him to patent.


And though the original Whittle Unit engine may not on display (as far as I know, if it even still exists) the W.1X that was sent to GE in the war is displayed in the jet gallery at the Smithsonian NASM. Where Whittle's contribution is expressed quite extensively.

Though probably the single most important component of Whittle's design, for the US, was the Shell combustor flame-can. Without this it would have taken far longer for the J35 and J30 axial designs to work reliably. (using annular chambers) As they switched to Whittle-style atomizing shell burners from the troublesome annular design. (which was proving to cause combustion instabillity)

 

[Soren]

The Russians agreed with him, and used a Russian version of the RR Nene rather than any German alternative for the Mig 15.

Thats incorrect bigZ. The Russians used the Whittle design for reliability reasons. The Jumo 004's axial flow design was inherently superior to Whittles centrifugal flow design.

Another reason for using the RR Nene design was for production reasons, as the most advanced German jet engines simply were beyond the capability of the Russian production industry.

 

[FLYBOYJ]

Thats incorrect bigZ. The Russians used the Whittle design for reliability reasons. The Jumo 004's axial flow design was inherently superior to Whittles centrifugal flow design.

Another reason for using the RR Nene design was for production reasons, as the most advanced German jet engines simply were beyond the capability of the Russian production industry.

Now there I have to agree Soren but at the same time if you have a superior engine and its not reliable, is it truly superior? Almost a "chicken or the egg" scenario.

 

[kool kitty89]

And remember the far lower thrust/weight of the Jumos. In fact the Russians did improve the 004 (RD-10) by using more high-temp alloys. They produced the 004D and 004E as the RD-10A and RD-10F iirc. The German designs that the Russians used just weren't powerful enough for medium-heavy sing-engined fighters. And the SFC, even in the 003 never went much below 1.4 lb/lbf/hr, while the Derwent V was ~1.12 and the Nene ~1.09 iirc.

The Russians did fail to develop some of the more advanced German designs, ie 004H, 012, 018. The 004H probably being the most reasonable for them, as it was the simplest and smallest and borrowed heavilly from the 004 design (adapted to a 012 2-spool mechanism). Fuel consumption was realitively low (~1.2 lb/lbf/hr) and performance, size, and weight were comperable to early J35 engines.(only slightly heavier and more powerful than the early 3750 lbf J35s)

But honestly I don't think the 004A/B/C/D/E was superior overall to the Derwent V or Nene (or J33). It was somewhat superior to the W.2 and Derwent, as low frontal-area per thrust it was better, though, reliabillity SFC, engine life, and thrust/weight were all lower. Even with the Alloys used in the Derwent the 004B would still be overweight and had vibration problems. Granted the 004D/E solved much of this But by then there was the Derwent IV of 2,400+ lbf and Whittle's 2,500 lbf W.2/700. (folled shortly by the Derwent V) The Goblin had similar advantages. And even the large area can be mitagated (in outboard engines) by mid-mounting them in the wings (to provide clearance without taller landing gear) and with good nacelle streamlining. The Meteor III with Derwent Is and long nacelles was capable of 520 mph with similar weight to the 262 (~14,400 lbs) and, thus similar thrust/weight. And this is with an obsolete/unadvanced (thick wing and tail) airframe.

Then again, the advanced 1,800 lbf Metrovick F.2/1 engines lost to the (technically inferior) Welland engine due to complexity, servicabillity, and reliabillity issues. It later even produced over 2,000 lbf at similar dementions to the 004B, but with weight ~1000 lbs. The 3,000-4,000 lbf Metrovick F.2/4 later outperformed the Derwint V (and later marks) but still never saw use. (except in the Saro Flying-boat fighter) It had similar overall performance to the J34 engine. (though though the J34 was somewhat thinner at 25 in diameter)

The real advantages of centrifugal engines is when they are used in single-engined fusalage mountings. The Vampire Mk I did ~540 mph with a 2,700 lbf Goblin I with a thrust/weight of only ~.26, though speed dropped to 531 mph in the Mk III due to weight increase (thrust/weight dropped to .25) despite the thrust increase of the Goblin II. The Vampire Mk II (trials only) outpaced even the P-80A and He-162A with its 4,500 lbf Nene at 570 mph and a thrust/weight of ~.41! And at lower SFC than the early goblin marks.

The P-80 was faster than the 262 with similar load and power with its fusalage-mounted J33.(and despite some loss of thrust due to a long jet-pipe) and range was much better due to the lower SFC of the J33.

And centrifugal engines are still produced, developed, and used today, not just in turobprops/shafts but in honest to godness jets, albeit only in the lower thrust range (<3500 lbf)

The only Class I engine that was clearly superior in overall design, reliabillity, producabillity, aerodynamic efficiency, fuel efficiency, thrust/weight, and practicality all weighed together would be the HeS-30 (109-006). (and possibly the 003, though it prooved difficult to produce within the timeframe, and was complex in construction) The HeS-30 had similar thrust to its contemporaries (860-910 kp, 1894-2004 lbf, with 2,400+ expected at 500mph) it weiged only ~860 lbs (about the same as the W.2) and was very small at ~24.4 in diameter ~107 in long. It was also somewhat simpler than the 004 and 003 with only a 5-stage compressor and 10 flame-cans, though it did use veriable exhaust guide-vanes. It also had SFC along the same lines of the HeS-011 and later 003s (~1.3 lb/lbf/hr) The only thing that was more complex or advanced compared to its competitors was the compressor design. The blades of the compressor had an aerofoil shape that allowed the rotors alone to do about half of the compression, the stators doing the other half.(opposed to other designs having stators do most). Such "high activity" compressor stages allowed the same air-flow and compression as 10 standars axial stages. The engine was developing rapidly in late '41 and was catching-up to the 003 and 004. In fact it may have beaten the 004B to production, and certainly the 003. But at the time the RLM, despite admitting the excelence of the design, thought the 004 and 003 were so far ahead that they simply didn't need another class I engine and canceled the project (along with the HeS-8 109-001) in favor of development of the class-II HeS-011. A decision that would proove to ve ironic in another 2 years...

Can you immagine an Me 262 with about the same power but 1450 lbs lighter with smaller, lighter, more fuel-efficient engines! Roll rate would increase considerably, as well as acceleration, top-speed, and range. Spool-up time was also markedly better and it needed less material to build.
Or a He 162 with 25% more thrust (not counting overrev) that weighed 380 lbs less! Assuming load stayed the same, the thrust/weight would go from ~.28 to ~.35 with some added range too due to reduced load and drag!

 

[Soren]

Koolkitty,

The Me-262A-1a was faster than the P-80A, even at its very conservative official figures of 870 km/h at alt. During British speed trials the Me-262 reached speeds of over 900 km/h in level flight.

Remember the early P-80A wasn't as fast as the later C model as I suspect you're under the impression that it was Koolkitty.

The Jumo 004B had an output of 8.8kN and weighed 719 kg, thats a power to weight ratio of 1.25 N/kg, and coupled with its much smaller aerodynamic drag this made it better than any contemporary Allied engine to make into operational use during WW2.

With the right metals the 004B could maintain 9.8kN for 10 hours, so the design was sound. The finished 720 kg 004C (Made with available metals) had a max output of 10kN.

If we are to look at designs which only just made it to be finished during the war then the HeS-011 is superior to all of them, with a output of 15.6kN while being very narrow and light it easily beats the heavier RR Nene engine which by then had a max output of 18.8kN.

 

[Crumpp]

Centrifugal compressors, which were used in the first jet engines, are still used on small turbojets and turboshaft engines and as pumps on rocket engines. Modern large turbojet and turbofan engines usually use axial compressors.

Why the change to axial compressors? An average, single-stage, centrifugal compressor can increase the pressure by a factor of 4. A similar single-stage axial compressor increases the pressure by only a factor of 1.2. But it is relatively easy to link together several stages and produce a multistage axial compressor. In the multistage compressor, the pressure is multiplied from row to row (8 stages at 1.2 per stage gives a factor of 4.3). It is much more difficult to produce an efficient multistage centrifugal compressor because the flow has to be ducted back to the axis at each stage. Because the flow is turned perpendicular to the axis, an engine with a centrifugal compressor tends to be wider (greater cross-sectional area) than a corresponding axial. This creates additional undesirable aircraft drag. Centrifugal compressors are also less efficient than axial compressors. For all of these reasons, most high compression jet engines use multi staged axial compressors. But, if only a moderate amount of compression is required, a centrifugal compressor is much simpler to use.

jet aircraft engine

All the best,

Crumpp

 

[kool kitty89]

But the HeS-011 was not practical for the time-frame. As I've said before, the 004 is by far not a bad design just not all that better overall than the best centrifugal designs of the time. Granted it was better for top-speed and low drag.

But the HeS-30 (109-006) is better than the 011 as well IMO. It could have entered service in the war (possibly before the 004B) and was more practical for the time-frame than the 011. It also had a higher thrust/weight and lower frontal area/thrust than the 004, 003, or 011. (though the advanced 003D was pushing it, but the 006 may have been even better by then)
With 900-910 kp (1984-2004 lbf) at only 390kg (859 lbs) weight ~24.4 in diameter ~107 in long it was far better than the 30+ in diameters of the 004 and 011 and still somewhat better than the 003. Comparing weight to thrust it's the clear winner 900-910kp/390kg (2.3+) compared to 900kp/720kg (~1.25) for the 004B, 1,300kp/~900kg (~1.44) for the 011A, and 800kp/562kg (1.42) for the 003A/E. These figures even beat the light-weight British and American centrifugal designs, until the Nene and Derwent V. Specific fuel consumption was some of the lowest of the German engines of the war (except the complex 2-spool and contra-rotating designs) at least as good as the 003 and 011 designs.
The 004A-E was actually slightly wider than the HeS-8 centrifugal design, though the 004's thrust output more than made up for this, though weight and fuel consumption was excessive.

The 1600 lbf J30 of 1945 (used on the Mc Donnell FH Phantom) was somewhat higher performing for size, weight, and SFC, but it came much later and the thrust was much lower. 19 in diameter ~690 lbs with <1.2 lb/lbf/hr sfc.

It wasn't beaten in overall thrust until the J34 was developed from the J30 (just after the war) to produce 3,000+ lbf at 25 in diameter, with ~1,160 lb weight with even lower SFC. The Metrovick F2/1 had beaten it in most catagories earlier but was as wide as the 004B. The F.2/4 produced around as much for a similar weight as the J34, but was still wider.
See: Westinghouse J34

I was using the figures for the P-80A which could do 556mph at SL with 492 mph at 40,000 ft. (slower at altitude due to wave-drag and higher parasitic drag and lower thrust iirc, maxing out around 10,000 ft) The P-80C was pushing 600 mph (~594 mph at SL and ~600 mph at 10,000 ft) as was the Meteor F8. The modified speed-record P-80B did 623+ mph near SL. The standard P-80B could do 577 mph The See: Lockheed P-80B Shooting Star

 

[davparlr]

Koolkitty,

The Me-262A-1a was faster than the P-80A, even at its very conservative official figures of 870 km/h at alt. During British speed trials the Me-262 reached speeds of over 900 km/h in level flight.

I think that more than a statement is required to justify this comment. The "conservative official" figure for the Me-262 is 541 mph (870 km/h) while the "conservative official" figure for the P-80A is 558 mph (898 km/h). You claim that the Me-262 achieved 559 mph (900 km/hr) during "speed trials". Speed trials indicate to me that modifications could be made to achieve max speed such as stripping down armament and armor, filling in cracks, flying with min fuel, etc. To accept this comment, I would like to see some documentation on configuration for the speed trial.


I don't know too much about the development of early jet engines or the plusses and minuses of centrifugal verses axial compressor during this era. I do know that, sense the axial compressor jet engine is the only fighter jet engine today, the centrifugal compressor was a dead-end street for this application (as was the Me-262 configuration a dead-end application for a fighter configuration). Also, it is apparent, that since the F-86 with its J-47, which was an axial design, and the Mig 15 with its VK-1 (really a Nene, a centrifugal design) were basically equal and this equality existed until the mid-50s, so too were the engines.

 

[AL Schlageter]

I don't know where Soren gets his info from but Mtt testing of the Me262 did not have the plane reach 900kph.