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Perhaps if he'd been paired with a larger/diversified team that split off to develop more conservative/practical derivatives of his concept it would have proceeded more quickly. (GE or pretty much any engine company probably could have handled that, particularly with the NACA experimental axtial compressor data published and available) Price's earlier centrifugal compressor driven steam turbine engine seemed to develop a lot more smoothly too, so a more direct followon to that design building on a similar compressor and turbine (rather than solely focusing on the incredibly complex, exotic, hybrid reciprocating, axial, intercooled L-1000 engine might have even paralleled Ohain and Whittle's work -in fact, given his paring with Lockheed, the arrangement would be very similar to Ohain's situation with jet engine experimentation at Heinkel in 1937-40 -prior to the Hirth merger in 1941).Nathan Prices work at Lockheed would probably have led to a workable and advanced axial jet.
Eastman Jacobs advanced aerodynamics for jakes jeep might have used it rather than a motor jet. It's a tragedy that Jacobs was keep out of the loop. The nazis often get accused of mismanagement but the U.S. Seems to have been more restrictive and Byzantine.
As a long-term research and development project it may have been interesting, but jumping straight into an extremely complex, ambitious design as the primary (and sole) focus is the problem there. Work on the simple, practical problems first and evolve from there. (likewise the L-133 transonic/supersonic fighter project was jumping headlong into an overly ambitious project without intermediate experimental or potential production designs) or Some of the more ambitious, exotic, and theoretically efficient german engine designs like BMW's 002 (or the many more ambitious designs brought over from Junkers with Wagner and Muller -the 5 stage reaction compressor design of the HeS 30 was noted as being the simplest and easiest to work with of Muller's various designs -and indeed, seems simpler than some of the test rigs built at Junkers before the consolidation with the Jumo project)The reheat between turbine stages is rather complex but Prices engine was extremely ambitious in terms of fuel efficiency and power to weight ratio and this is what had to be done within the constraints of available materials. The reheat between stages is perhaps over the top but no doubt someone has tried it and proven that it is possible and workable.
I was under the impression that there was still a great deal of secrecy as far as trade secrets, direct competition between firms, and relative lack of cooperation and exchange of information between said firms. Useful information may have been more widely published than in the US (after 1939) but perhaps somewhat worse (or just different?) than the likes of the NACA studies being shared pre-war.Secrecy in the US meant that the best aerodynamicists and reaction engine designers did not work together. This is something the Germans did very well.
The L-1000 ended up the J37 and continued development post-war for an extended period and never materialized a production design. The research probably contributed useful data and experience for later projects, but nothing directly came of the J37.Prices focus on fuel efficiency may have seen him come up with a winning engine that dominated the commercial market.
And many pre-war bombers were based on airliners, the two are generally interconnected and somewhat interchangeable, but also tend to be more efficient when expressly engineered for the task. As such, airliners likely would have been superior to the bomber derived ones used post-war.Post war civilian airliners were modified bombers, without that massive investment there would be no civilian airline industry and without a war jet engines would have taken years to get off the ground (literally). Whittles patents lapsed due to a lack of interest
Without the build up to world war two through the thirties maybe another 20 years to develop but without a war what would you use them in? Post war civilian airliners were modified bombers, without that massive investment there would be no civilian airline industry and without a war jet engines would have taken years to get off the ground (literally). Whittles patents lapsed due to a lack of interest
In my opinion, the most advance aircraft in 1938 (a non-war stimulated economy) was the DC-4, a big, fast aircraft and, with optional pressurization (never used), which also represented the first modern airliner (its basic design was used by the airlines well into the 60's).
The point I was making was how little interest there was until a war appeared. Whittles patents were filed in 1930 by an RAF employee, 10 years later the RAFs front line fighter was a piston engined plane with in many cases a wooden prop, but 4 years after that there were jet powered fighters coming into service.And many pre-war bombers were based on airliners, the two are generally interconnected and somewhat interchangeable, but also tend to be more efficient when expressly engineered for the task. As such, airliners likely would have been superior to the bomber derived ones used post-war.
Whittle's patents had already lapsed pre-war and his work had already inspired some others to make their own attempts (namely Halford with the Goblin). A.A. Grifith had already started his own turboprop developments independently and may have continued along that path without bothering with pure jets initially. (he may have skipped over inefficient turbojets entirely and gone for high speed prop fans when getting into transonic airliner requirements)
The problem is Whittle's military position, along with social status and luck/chance. Halford, Griffith, Price, and Ohain were all independent engineered that ended up having their research and development funded as private ventures. (I think Bramo, BMW, Junkers airframe division, and Jumo were developing engines as private ventures pre-war as well, or at least some of them were -I believe Bramo was working on preliminary jet engine development prior to the BMW merger)The point I was making was how little interest there was until a war appeared. Whittles patents were filed in 1930 by an RAF employee, 10 years later the RAFs front line fighter was a piston engined plane with in many cases a wooden prop, but 4 years after that there were jet powered fighters coming into service.
Indeed, the interest would be airliners and experimental aircraft. (and record breaking high speed flights) Heinkel at least was very much interested in funding such ventures.Since the world's economy was slowly pulling out of the depression, I do not think the military, due to pathetic funding, would have been the main pusher of advance aircraft design but rather the civilian airliner industry. In my opinion, the most advance aircraft in 1938 (a non-war stimulated economy) was the DC-4, a big, fast aircraft and, with optional pressurization (never used), which also represented the first modern airliner (its basic design was used by the airlines well into the 60's). Their new, burgeoning business would spur their desire for faster, larger, longer ranged, aircraft. As such I can see a real, although poorly funded, push toward a turboprop engine. U.S. manufacturers were very interested in maintaining their superiority in the passenger aircraft market so I think they would not have been far behind any competitor design.
In terms of mass production, I agree (even with the war, the mature versions of engines in any country didn't really arrive until 1945 -albeit with a good bit of mismanagement and material shortages), but in terms of experimental design work, it may have gone faster in some areas, slower in others.In general, I think, due to low funding, turbojet development worldwide would have been delayed at least five years with 1945 jet technology not occurring until 1950, and would have been quite competitive.
None of those engines are turbofans, though, and the J48 is more directly comparable to the J35, J47, Orenda, and maybe some models of the Avon. The J48/Tay compares very favorably in fuel consumption to all of those, better than some, only slightly worse in others, and managed more thrust at lower weight than the J35 or J47 without afterburning. (and much lower weight than the Avon) The Metrovik F.2 and Beryl are somewhat smaller but don't appear more complex than the likes of those axial engines. (and the turbofan and propfan derivatives put them closer to the thrust class as well, at even lower fuel consumption)The other problem with complicated engines is that the bar is always moving. A P&W JT-3C turbo jet used about 2/3 the fuel per pound of thrust as a P&W J48 (JT-7 or RR Tay) did. It also weighed about 3/4s as much per pound of thrust.
A very complicated engine designed to do much better than the Centrifugal turbo jets of the 40s might not show up well against the high pressure ratio (12:1 and higher) axial turbo jets of the 50s. Granted these high pressure ratio Axial engines were anything but simple in their own way. Two spools or variable stators. The heat exchanger idea seems to capture the fancy of idealists looking the best efficiency but it seldom, if ever, worked out in practice.
according to wiki
Not knocking your post but anything after 1936 in aviation was affected by the war.
Many post war airliners were based on the B 29, a civilian airline industry could not take the teething problems with the engines. Post war people were accustomed to the idea that you could fly thousands of miles safely over water.
None of those engines are turbofans, though, and the J48 is more directly comparable to the J35, J47, Orenda, and maybe some models of the Avon. The J48/Tay compares very favorably in fuel consumption to all of those, better than some, only slightly worse in others, and managed more thrust at lower weight than the J35 or J47 without afterburning. (and much lower weight than the Avon) The Metrovik F.2 and Beryl are somewhat smaller but don't appear more complex than the likes of those axial engines. (and the turbofan and propfan derivatives put them closer to the thrust class as well, at even lower fuel consumption)
The Ghost compares less favorably (as would the Goblin next to the Derwent V or 8 ) in terms of thrust to weight and diameter, though fuel consumption is similar and mechanical complexity is likely the lowest of the lot. (by extension, hypothetical turbofan derivatives of said engines would be the simplest of the lot, and likely also considerably simpler than any of the above axial turbojets as they are without fans)
Centrifugal engines are also so large in diameter, that little/no increase in maximum diameter would result from rear-fan turbofan implementations, though additional/larger air intakes would be required, obviously.
Agreed. Starting at the top with an extremely complex design really doesn't seem like a practical model. Scaling back to the simplest possible form (at last for experimental and proof of concept testing -as whittle and ohan did) and then moving on from there would be most sensible and logical. (and likely would have spurred more serious turbine engine development with other manufacturers in the US early on)People used the Wright Turbo-compound because they had to, it was not well liked. Several other similar engines in concept never made it out of the experimental shops.
If there's a genuine engineering reason bypass/augmentor fans weren't adopted sooner, I'd certainly like to find out what it is. I suppose it could simply be that the idea didn't occur to many engineers early on in development of turbine engines or testing/implementation of development programs for such devices were overlooked/delayed for various reasons unrelated to technical difficulties. (similar to the American engine industry as a whole starting turbojet/turboprop development en mass a bit late)I don't know what the problem was with turbo-fans but it seems to have take until the late 50s for them to catch on.
Going by Wilkinson's "Aircraft Engines of the World" which means what it announced to the "public" and not what is going on behind closed doors.
Somehow I missed this before, but the reasoning fits very much with what I said in post 19 above. It does still seem like DeHavilland is the odd one out that should have had more interested in turbofan development.Without digging into, my Kay books, I have a theory on the late fan development. Post WW2 and the cold war era engine development was pushed by military specifications rather than by commercial needs and, during this period, that meant higher and faster. With the advent of aerial refueling, even bombers pushed speed over efficiency. Speed and altitude meant turbojets. In the mid 50s things started to change. With the advent of new engines, J-57, J-79, J-75, with afterburners, the military had the engines capable of pushing warplanes, even bombers to the aerodynamic heating limit of aluminum, a realistic limit for the technology of the day (and today?). With that limit reached, efficiency and range became more important to the military, particularly the B-52, and fans appeared. I do not think the technology was imposing as P&W offered kits that could upgrade the J-57 to the JT3D in overhaul shops (per Kay, I did finally pull it out).