KJ_Lesnick
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I'm curious what would have happened if the US had developed gas-turbines or pursued high-speed flight earlier?
Overview: 1926-1931
There were a number of missed opportunities in the area of high-speed flight: The first would have obviously been in the 1926-1931 period. A few years earlier Edgar Buckingham had published some basic research on gas-turibnes and found them totally unsuitable for aircraft use based on the fact that while the size requirement and efficiency increased to a degree with speed, by 250 mph would still consume four times the amount of fuel as a piston driven aircraft flying at the same speed (I'm surprised he didn't consider the possibility aircraft would get faster than 250 mph when they had already gone from 30 mph with the Wright Flyer to around 233 by February of 1923). There were some scientists at NACA who actually wanted to test the concept out for real, and see if Buckingham's conclusions were valid, during the 1926-1927 period. For one reason or another, this proposal was rejected.
Meanwhile, on the other side of the Atlantic Ocean, in 1928, Frank Whittle had concluded that propeller aircraft were reaching the point of diminishing returns (not sure how he concluded this) and felt that a new powerplant was needed to achieve higher speeds. His initial proposal was a motor-jet (a piston engine driving a propeller, or fan, which fed an afterburner), and anticipated efficiency problems at low altitude would be compensated for in the thinner air at high altitudes, and projected speeds of 500 mph. He felt that over a sufficient range, the high altitude speed would effectively give it the ability to ultimately out-do a piston-driven aircraft. By the next year, he had decided to revamp the whole design into a gas-turbine. By 1930, the RAF seemed largely unenthused with Frank Whittle's gas-turbine proposal, and refused to pursue it, or make it a national secret. Because of this, his design was public knowledge, and was patented it. I'm not sure how long it takes to submit an idea for patenting, and when it's patented, or how assiduously other people in the engineering fields sift through patent proposals to find ideas.
Alternative-History Speculation
It would have been a hell of an interesting alternate history scenario if NACA got the go ahead to build a gas-turbine in the 1926-1927 era, or found Whittle's concept in a patent-search; then proceeded to develop the idea from that. In either case, we probably would have likely been the first nation to build a jet-engine.
Though I'm not sure if we had the aerodynamics to make such a design work existed back then, I assume that engineering would have met the challenge. Regardless, I'm not sure how long it would take, which raises a good question.
I'd assume that trans-sonic issues would have been more costly to work through than they were in 1939 as we'd have more primitive wind-tunnels to test them out. The problems would likely have been more bewildering, leaving us spending more time to figure out what the hell was happening to the planes at that time-period. I would assume that in addition to mach-tuck, one would also see various structural break-ups occurring with more regularity as it was more common to see aircraft made out of wood and fabric in that timeframe. I assume that wind-tunnel advancement would accelerate to match the challenge, though I'm not sure how long it would take.
Regardless, I'm curious in such a scenario if WWII would be fought largely with jet-powered aircraft or even using more novel propulsion systems?
Overview II: 1931-1940: High Speed Flight & Gas-Turbines
In the United States, there were numerous problems regarding NACA, and developments of novel power-plants. While early on, there were some people who did want to see if a gas-turbine could work; it seemed that after that point, there was an attitude among many that seemed to persist that the piston/propeller would always be the power-plant of aircraft. Some of this of course was the fact that engine manufacturers probably felt there was a lot of growth potential in piston-engines and propeller driven designs, as well as the fact that it kept the status quo in their favor (it's fundamentally easier to develop an existing concept, than do something totally new). NACA, as a result, put little research into the development of new power-plants and, instead focused on the subject of incremental advancement (I know some engineers came from industry, so I'm not sure if a revolving-door dynamic existed).
During the mid-to-late 1930's, it would appear that both gas-turbines, and an earlier pursuit of trans-sonic and supersonic flight existed: Starting in 1935, in Volta, Italy, there was a conference on a number of scientific fields, which included one entitled "High Velocities in Aviation". The subjects of compressibility and swept wings, as well as ramjets were mentioned. A variety of scientists were present, some from the US (Eastman Jacobs), the UK, others from Italy and Germany. While General Arnold forbid his personnel from attending, it's possible that some of the civilian scientists in the US Army Air Corps attended anyway as well. Regardless, information from NACA leaked into the US Army Air Corps.
During the 1930's (at the very latest in 1936), Eastman Jacobs became interested in the subject of creating supersonic wind-tunnels. It's not clear how effective his designs were, but he did observe Schlieren waves, which indicates at least some of the flow was indeed supersonic.
By 1939, the P-38 flew, and while some just believed it was a flutter problem, there were a few who knew better. Ezra Kotcher had concluded that what was going on appeared to be compressibility, and by August, 1939 (just before the start of WWII in Europe), sent a memo to General Arnold, discussing the problems with the P-38 relating to compressibility. He recommended a high-speed research program be instituted with either rockets or gas-turbines used for the purpose. For one reason or another it was ignored (it might have been the chaos involved in the start of war in Europe).
The obstacles were as follows
1. Since the late 1920's there was a pervasive attitude that pistons and propellers would remain as the aircraft power-plant forevermore (The fact that much of the propulsion industry had little interest in adopting new methods did not help). NACA had since the early 1920's vigorously defended itself as being THE authority on theoretical aviation research; the US Army and Navy's job with aviation was to be applied research. While, I cannot say I technically oppose this layout: It depends on NACA having done it's job, and because they had reduced budgetary funding on new propulsion methods, and focused on incremental advancement; they unwittingly shot themselves in the foot :
. Even in the 1940's they were still fixated on motor-jets while the UK and Germany were all developing gas-turbines.
2. There was a pervasive problem with the subject of multi-disciplinary research in the USAAC at the very least (the US Navy might very well have been more creative, particularly since the early/mid-1930's as they started seeing proposals for monoplane aircraft to operate off aircraft carriers), though this may very well have included NACA as well. We may have had scientists that were skilled within their discipline, but were a little rusty, more often than not, outside that discipline in many cases. There were, of course exceptions, such as Ezra Kotcher, who ran the Air Corps Engineering School (he might have been a civilian early on, but by 1942 he was definitely an officer). By the late 1930's (Kotcher was working for the Army by 1937) it would appear there were more enthusiasm for ideas of jet-powerplants (I'm not sure how many ideas revolved around motor-jets or gas-turbines) among scientists/engineers at least, as Kotcher jokingly said that you couldn't throw a bottle of booze out a window without hitting a scientist who had some idea revolving around this.
3. I don't think the US built too many proof of concept aircraft. In other words, an aircraft designed to evaluate a concept. England and Europe built them.
Alternate History Speculation/Ideas
Early Gas Turbine & Motorjet Designers: NACA was often fixated on incremental research in piston engines than new ideas in propulsion and may/may not have had issues with multi-disciplinary engineering skills (anybody able to verify/refute this?). Those who worked in the private sector were not as inhibited as governments were, and often by necessity, possessed multi-disciplinary skills. I do know of two designers: Cliff Garret, and Nathan Price, who both had proposals for gas-turbines. I know Price started up with his idea in 1938, and while Garrett came into existence in 1936, I don't know when his first proposals were. I'm not sure if any other designers had started looking into the idea (I've started to comb the propulsion forum) for either axial or centrifugal-flow ideas. If such a design had been conceptualized as either a turboprop or pure-jet and then submitted to NACA and caught the attention of somebody who saw the opportunity, it would have potentially had provided an earlier development potential for gas-turbines.
Those who knew of, or thought of motorjets were probably more numerous. Since Frank Whittle had thought of the idea originally, then substituted the idea into a gas-turbine. It would be an interesting point of contemplation if somebody else did something similar.
High-Subsonic and Supersonic Wind-Tunnels: In the mid-1930's, Eastman Jacobs started developing an interest in supersonic wind-tunnels (I'm not sure if the tunnel was subsonic with an object in the tunnel accelerating it over, or fully supersonic). In 1939, Ezra Kotcher knew about the fact that the P-38 was suffering from compressibility and suggested to General Arnold, the development of a high-speed wind-tunnel (speeds aimed at least just below Mach 1) and some form of jet-engine or rocket to test the concept out.
It would be interesting to contemplate what would happen Kotcher's request was granted either totally or to some extent. Frankly, I'm curious for example if we would have started developing fully supersonic tunnels, and exploded ahead like the Germans did in WWII, or if we would have proceeded along at a more leisurely clip.
Overview: 1926-1931
There were a number of missed opportunities in the area of high-speed flight: The first would have obviously been in the 1926-1931 period. A few years earlier Edgar Buckingham had published some basic research on gas-turibnes and found them totally unsuitable for aircraft use based on the fact that while the size requirement and efficiency increased to a degree with speed, by 250 mph would still consume four times the amount of fuel as a piston driven aircraft flying at the same speed (I'm surprised he didn't consider the possibility aircraft would get faster than 250 mph when they had already gone from 30 mph with the Wright Flyer to around 233 by February of 1923). There were some scientists at NACA who actually wanted to test the concept out for real, and see if Buckingham's conclusions were valid, during the 1926-1927 period. For one reason or another, this proposal was rejected.
Meanwhile, on the other side of the Atlantic Ocean, in 1928, Frank Whittle had concluded that propeller aircraft were reaching the point of diminishing returns (not sure how he concluded this) and felt that a new powerplant was needed to achieve higher speeds. His initial proposal was a motor-jet (a piston engine driving a propeller, or fan, which fed an afterburner), and anticipated efficiency problems at low altitude would be compensated for in the thinner air at high altitudes, and projected speeds of 500 mph. He felt that over a sufficient range, the high altitude speed would effectively give it the ability to ultimately out-do a piston-driven aircraft. By the next year, he had decided to revamp the whole design into a gas-turbine. By 1930, the RAF seemed largely unenthused with Frank Whittle's gas-turbine proposal, and refused to pursue it, or make it a national secret. Because of this, his design was public knowledge, and was patented it. I'm not sure how long it takes to submit an idea for patenting, and when it's patented, or how assiduously other people in the engineering fields sift through patent proposals to find ideas.
Alternative-History Speculation
It would have been a hell of an interesting alternate history scenario if NACA got the go ahead to build a gas-turbine in the 1926-1927 era, or found Whittle's concept in a patent-search; then proceeded to develop the idea from that. In either case, we probably would have likely been the first nation to build a jet-engine.
Though I'm not sure if we had the aerodynamics to make such a design work existed back then, I assume that engineering would have met the challenge. Regardless, I'm not sure how long it would take, which raises a good question.
I'd assume that trans-sonic issues would have been more costly to work through than they were in 1939 as we'd have more primitive wind-tunnels to test them out. The problems would likely have been more bewildering, leaving us spending more time to figure out what the hell was happening to the planes at that time-period. I would assume that in addition to mach-tuck, one would also see various structural break-ups occurring with more regularity as it was more common to see aircraft made out of wood and fabric in that timeframe. I assume that wind-tunnel advancement would accelerate to match the challenge, though I'm not sure how long it would take.
Regardless, I'm curious in such a scenario if WWII would be fought largely with jet-powered aircraft or even using more novel propulsion systems?
Overview II: 1931-1940: High Speed Flight & Gas-Turbines
In the United States, there were numerous problems regarding NACA, and developments of novel power-plants. While early on, there were some people who did want to see if a gas-turbine could work; it seemed that after that point, there was an attitude among many that seemed to persist that the piston/propeller would always be the power-plant of aircraft. Some of this of course was the fact that engine manufacturers probably felt there was a lot of growth potential in piston-engines and propeller driven designs, as well as the fact that it kept the status quo in their favor (it's fundamentally easier to develop an existing concept, than do something totally new). NACA, as a result, put little research into the development of new power-plants and, instead focused on the subject of incremental advancement (I know some engineers came from industry, so I'm not sure if a revolving-door dynamic existed).
During the mid-to-late 1930's, it would appear that both gas-turbines, and an earlier pursuit of trans-sonic and supersonic flight existed: Starting in 1935, in Volta, Italy, there was a conference on a number of scientific fields, which included one entitled "High Velocities in Aviation". The subjects of compressibility and swept wings, as well as ramjets were mentioned. A variety of scientists were present, some from the US (Eastman Jacobs), the UK, others from Italy and Germany. While General Arnold forbid his personnel from attending, it's possible that some of the civilian scientists in the US Army Air Corps attended anyway as well. Regardless, information from NACA leaked into the US Army Air Corps.
During the 1930's (at the very latest in 1936), Eastman Jacobs became interested in the subject of creating supersonic wind-tunnels. It's not clear how effective his designs were, but he did observe Schlieren waves, which indicates at least some of the flow was indeed supersonic.
By 1939, the P-38 flew, and while some just believed it was a flutter problem, there were a few who knew better. Ezra Kotcher had concluded that what was going on appeared to be compressibility, and by August, 1939 (just before the start of WWII in Europe), sent a memo to General Arnold, discussing the problems with the P-38 relating to compressibility. He recommended a high-speed research program be instituted with either rockets or gas-turbines used for the purpose. For one reason or another it was ignored (it might have been the chaos involved in the start of war in Europe).
The obstacles were as follows
1. Since the late 1920's there was a pervasive attitude that pistons and propellers would remain as the aircraft power-plant forevermore (The fact that much of the propulsion industry had little interest in adopting new methods did not help). NACA had since the early 1920's vigorously defended itself as being THE authority on theoretical aviation research; the US Army and Navy's job with aviation was to be applied research. While, I cannot say I technically oppose this layout: It depends on NACA having done it's job, and because they had reduced budgetary funding on new propulsion methods, and focused on incremental advancement; they unwittingly shot themselves in the foot :
. Even in the 1940's they were still fixated on motor-jets while the UK and Germany were all developing gas-turbines.2. There was a pervasive problem with the subject of multi-disciplinary research in the USAAC at the very least (the US Navy might very well have been more creative, particularly since the early/mid-1930's as they started seeing proposals for monoplane aircraft to operate off aircraft carriers), though this may very well have included NACA as well. We may have had scientists that were skilled within their discipline, but were a little rusty, more often than not, outside that discipline in many cases. There were, of course exceptions, such as Ezra Kotcher, who ran the Air Corps Engineering School (he might have been a civilian early on, but by 1942 he was definitely an officer). By the late 1930's (Kotcher was working for the Army by 1937) it would appear there were more enthusiasm for ideas of jet-powerplants (I'm not sure how many ideas revolved around motor-jets or gas-turbines) among scientists/engineers at least, as Kotcher jokingly said that you couldn't throw a bottle of booze out a window without hitting a scientist who had some idea revolving around this.
3. I don't think the US built too many proof of concept aircraft. In other words, an aircraft designed to evaluate a concept. England and Europe built them.
Alternate History Speculation/Ideas
Early Gas Turbine & Motorjet Designers: NACA was often fixated on incremental research in piston engines than new ideas in propulsion and may/may not have had issues with multi-disciplinary engineering skills (anybody able to verify/refute this?). Those who worked in the private sector were not as inhibited as governments were, and often by necessity, possessed multi-disciplinary skills. I do know of two designers: Cliff Garret, and Nathan Price, who both had proposals for gas-turbines. I know Price started up with his idea in 1938, and while Garrett came into existence in 1936, I don't know when his first proposals were. I'm not sure if any other designers had started looking into the idea (I've started to comb the propulsion forum) for either axial or centrifugal-flow ideas. If such a design had been conceptualized as either a turboprop or pure-jet and then submitted to NACA and caught the attention of somebody who saw the opportunity, it would have potentially had provided an earlier development potential for gas-turbines.
Those who knew of, or thought of motorjets were probably more numerous. Since Frank Whittle had thought of the idea originally, then substituted the idea into a gas-turbine. It would be an interesting point of contemplation if somebody else did something similar.
High-Subsonic and Supersonic Wind-Tunnels: In the mid-1930's, Eastman Jacobs started developing an interest in supersonic wind-tunnels (I'm not sure if the tunnel was subsonic with an object in the tunnel accelerating it over, or fully supersonic). In 1939, Ezra Kotcher knew about the fact that the P-38 was suffering from compressibility and suggested to General Arnold, the development of a high-speed wind-tunnel (speeds aimed at least just below Mach 1) and some form of jet-engine or rocket to test the concept out.
It would be interesting to contemplate what would happen Kotcher's request was granted either totally or to some extent. Frankly, I'm curious for example if we would have started developing fully supersonic tunnels, and exploded ahead like the Germans did in WWII, or if we would have proceeded along at a more leisurely clip.
