First Aircraft to Use a Symmetrical Airfoil
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Bearfoil
I'm sure you're right; I recall reading a similar story. However, to the best of my knowledge the DH Comet 1 was not designed ever to go intentionally supersonic, but I believe had a symmetrical aerofoil, although I have no idea whether it was also laminar. Does anyone know why, especially as it was quickly exposed as a major liability?
I want to say that the Bell X-1 wing was symmetrical.? The body had a purpose built shape of a .45 caliber bullet, the designers agreed that that projectile went super, and I think that is a true story.
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Iron Duck
deHavilland had some brilliant wins, and some misses too. Was it the swallow that took Geoffrey? I don't check anything I write, first of all, I think anyone can go wikigoogle and then write here, but why? Also, there are so many pedants and wiseacres here, I always find out what's what, and sometimes I throw in some goof, to tease. Bad Bear.
The Comet was star crossed, A beautiful expression of the Art, except the tail. It was some butt ugly tail feather, imo.
cheers bear
deHavilland had some brilliant wins, and some misses too. Was it the swallow that took Geoffrey? I don't check anything I write, first of all, I think anyone can go wikigoogle and then write here, but why? Also, there are so many pedants and wiseacres here, I always find out what's what, and sometimes I throw in some goof, to tease. Bad Bear.
The Comet was star crossed, A beautiful expression of the Art, except the tail. It was some butt ugly tail feather, imo.
cheers bear
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Bearfoil
Sure, but at the risk of sounding like a cracked record, why did it have a symmetrical aerofoil, if it did?
The Comet was star crossed, A beautiful expression of the Art, except the tail. It was some butt ugly tail feather, imo.
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MECHTA
You've got that a little backward Mechta. The turbocharger output is controlled by a WASTEGATE, a variable valve in the exhaust pipe ahead of the turbo that directs exhaust gas either through the turbo or bypass to atmosphere. At low altitude, where little boost is needed, the wastegate is mostly open, bypassing the turbo. As altitude increases, the wastegate gradually closes to direct more flow through the turbo & therefore increase its rpm & output up to the rpm limit of the turbocharger. Properly sized & controlled, the turbo can maintain sea level manifold pressure to any altitude.
The mechanical supercharger does loose with altitude & to overcome this, two speed & later two-stage (one blowing into another) supercharging were employed in later model Mustangs, Spitfires, etc to maintain power above thirty thousand feet.
Boosting air pressure, whether by mechanical or turbo, leads to greatly increased intake air temperature, which is not conducive to high power output. To counter this, complex intercooler & even aftercooler heat exchangers were employed in the intake downstream of the supercharger to reduce intake air temp & prevent detonation. Very high octane fuels had to be developed to work in these highly boosted engines at high altitude.
All of this development, done some 70 years ago during the emergency of a world war, is now beginning to show up in autos, where a tiny 2 liter four cylinder turbocharged & intercooled engine can produce the 300 horsepower of yesterdays V8 at a fraction of the fuel consumption.
The mechanical supercharger does loose with altitude & to overcome this, two speed & later two-stage (one blowing into another) supercharging were employed in later model Mustangs, Spitfires, etc to maintain power above thirty thousand feet.
Boosting air pressure, whether by mechanical or turbo, leads to greatly increased intake air temperature, which is not conducive to high power output. To counter this, complex intercooler & even aftercooler heat exchangers were employed in the intake downstream of the supercharger to reduce intake air temp & prevent detonation. Very high octane fuels had to be developed to work in these highly boosted engines at high altitude.
All of this development, done some 70 years ago during the emergency of a world war, is now beginning to show up in autos, where a tiny 2 liter four cylinder turbocharged & intercooled engine can produce the 300 horsepower of yesterdays V8 at a fraction of the fuel consumption.
Last edited by BobM2; 8th Jan 2011 at 01:12.
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bearfoil,
I know the P-38 had turbos, which had to do with the high-altitude requirement. Regardless, the USAAC didn't seem to believe that high altitude performance was very important in fighter-aircraft until around the time of WW2.
I didn't know that the P-38 had that feature, though I knew the Allison V-1710 was designed with the ability to turn the crankshaft clockwise or counter-clockwise
Yup, it was developed in 1938 as an interceptor. Truthfully the aircraft was technically a heavy-fighter/interceptor. At the time the Army felt that fighters should only be single engined and have no larger than 500 pounds of weapons; Two USAAC Lieutenants, Gordon Saville and Benjamin Kelsey decided to call the aircraft an interceptor to bypass the requirements. They wanted 1,000 pounds of bombs, and up to two engines.
barit1,
Well, the mid to late 1930's, they started using turbochargers on bombers, but they largely felt that most fighters didn't need high-altitude capability; the P-38, P-47, (and technically the P-51) featured turbochargers because they were classified as interceptors (which was simply used to get around inflexible Army Air Corps requirements concerning fighters); once WWII was underway, turbocharged designs became more common.
Actually, that was in 1918. I'm not sure why it took them until the mid 1930's before they started using them in aircraft though, regardless, the Army seemed to only see their use as being important in bombers and transports which were designed to fly at high-altitudes; they didn't feel high-altitudes were important in a fighter.
Brian Abraham,
Probably the P-51...
BobM2,
Actually, not every air-power advocate felt that way
* General Giulio Douhet did, especially by the time he wrote "Command of the Air".
* General Billy Mitchell did not, and stated that fighter escort was essential to a strategic bombing campaign
* The Bomber Mafia consisted of a number of people who held a variety of views
- Some were inspired by large gun-bristling bombers similar to the Caproni Ca.5. There were some who felt that they could simply fend for themselves provided they were fitted with loads of turrets and heavily armored and basically "the bomber would always get through".
- Most actually felt that maneuverable fighters were inherently useful (though the exact degree this was felt varied). Regardless, they failed to think up a design that would meet the range requirements while still retaining sufficient agility (and possibly dealing with various Army requirements for fighters), and as a result, they gave up on the idea of using fighters and went with the idea of building large, heavy, gun-bristling bombers instead.
I don't know the exact numbers, but if I recall, they were routinely losing 20% of their bombers. Most people don't really think of this, but while modern-day bombers have a crew of 2 to 4; back then bombers had crews of 10 (all the turret operators). When a bomber went down, you could lose up to 10 people.
Mechta,
Was the rotational velocity of the turbocharger supersonic on designs of that era?
The Lockheed "Lightning" or P-38, had turbocharging, each unit was aft of the Engine mounted on the Boom.
The engines were contra rotating (There was a Left, and a Right, problematic in the field).
This a/c was developed pre War, by Kelly Johnson, one of his first masterpieces.
barit1,
The Army Air Corps was NOT averse to turbos. Republic, Lockheed, and Curtiss all built prototypes using Army-specified turbos, and the P-47 and P-38 (both with innovative layouts) won production contracts. Likewise the B-17 and B-24.
In fact, the Army flight-tested a LaPere bipe with a GE-turbosupercharged Liberty engine in 1919, setting a new altitude record in the process.
Brian Abraham,
You sure you don't mean laminar airfoil and turbocharging barit? I know the answer to that one.
BobM2,
Of course, the pre-war AAC bomber boys thought their high-flying formations of B-17's & B-24's didn't need fighter escort.
* General Giulio Douhet did, especially by the time he wrote "Command of the Air".
* General Billy Mitchell did not, and stated that fighter escort was essential to a strategic bombing campaign
* The Bomber Mafia consisted of a number of people who held a variety of views
- Some were inspired by large gun-bristling bombers similar to the Caproni Ca.5. There were some who felt that they could simply fend for themselves provided they were fitted with loads of turrets and heavily armored and basically "the bomber would always get through".
- Most actually felt that maneuverable fighters were inherently useful (though the exact degree this was felt varied). Regardless, they failed to think up a design that would meet the range requirements while still retaining sufficient agility (and possibly dealing with various Army requirements for fighters), and as a result, they gave up on the idea of using fighters and went with the idea of building large, heavy, gun-bristling bombers instead.
They paid the price in Europe with greater losses than the Marines in the S. Pacific.
Mechta,
The advantage of the turbocharger is that its speed is determined by the density of the air it is compressing, to some extent independently of the engine rpm. This means as you fly higher, and the incoming air is less dense, it will rotate faster until the air exiting the compressor is at approximately the pressure it would be at a lower altitude.
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Jane-DoH
Perhaps this might help, an old reprinted article from 1943 from the folks that made the most in the USA at that time. In the old days they called them Turbosuperchargers, later, shortened to turbochargers.
The turbine blades (called buckets in those days) were made from Vitallium, an alloy of 60% cobalt, 20% chromium, 5% molybdenum, and a few other elements. The alloy was invented for use in dentistry and artificial joints, because of its light weight (at that time, not today) and resistance to corrosion. It was used for components of turbochargers because of its thermal resistance. Vitallium was developed by Albert W. Merrick for the Austenal Laboratories in 1932.
The Turbosupercharger and the Airplane Power Plant
Turbine D
Perhaps this might help, an old reprinted article from 1943 from the folks that made the most in the USA at that time. In the old days they called them Turbosuperchargers, later, shortened to turbochargers.
The turbine blades (called buckets in those days) were made from Vitallium, an alloy of 60% cobalt, 20% chromium, 5% molybdenum, and a few other elements. The alloy was invented for use in dentistry and artificial joints, because of its light weight (at that time, not today) and resistance to corrosion. It was used for components of turbochargers because of its thermal resistance. Vitallium was developed by Albert W. Merrick for the Austenal Laboratories in 1932.
The Turbosupercharger and the Airplane Power Plant
Turbine D
Last edited by Turbine D; 8th Jan 2011 at 01:34. Reason: Added material note
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Jane-DoH
I'm not sure why it took them until the mid 1930's before they started using them in aircraft though, regardless, the Army seemed to only see their use as being important in bombers and transports which were designed to fly at high-altitudes; they didn't feel high-altitudes were important in a fighter.
Well, the mid to late 1930's, they started using turbochargers on bombers, but they largely felt that most fighters didn't need high-altitude capability; the P-38, P-47, (and technically the P-51) featured turbochargers because they were classified as interceptors (which was simply used to get around inflexible Army Air Corps requirements concerning fighters)
Other thoughts:
No P-51 either Allison or Merlin ever had turbocharging
Billy Mitchell, the most forward-thinking General in army aviation, was canned by the "old guard" ground officers in the mid '20s, so had no influence on events of the '30s.
No turbo operates supersonically.
Turbine D has provided a great link.
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BobM2,
What aircraft were those?
I was under the impression that the Germans and British were ahead of us when it came to turbocharger development in fighters.
They weren't part of the equation because they couldn't think of a design that would meet the range-requirements to escort the bombers as well as maintain maneuverability, maybe funding might have been an issue too, but the Bomber Mafia did see value in fighters if they could have achieved the range to escort the bombers.
Really, I was always under the impression that the Merlin version did... if you're right, you learn something new every day
That I know, still he was a big proponent of using fighter escorts. He also was a big advocate of developing turbochargers, reliable gunsights, and aerial-torpedoes.
Fascinating to think of what would have happened had he succeeded
Just to be clear we're talking about the same thing, you mean a supersonic tip velocity due to rotational speed right?
Actually the AAC had a few turbocharged aircraft in the '20s but...the early turbos were expensive & not too reliable.
So far as I know, no other country, allied or axis, produced even one.
Offensive single engine single seat fighters were apparently not part of the equation
No P-51 either Allison or Merlin ever had turbocharging
Billy Mitchell, the most forward-thinking General in army aviation, was canned by the "old guard" ground officers in the mid '20s, so had no influence on events of the '30s.
Fascinating to think of what would have happened had he succeeded
No turbo operates supersonically.
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The only allied aircraft to use turbocharging (off the top of the head) during WWII were the the P-38, P-47, B-17 and B-24. The P-51 did not use turbocharging. The P-38 was a flop in the European theatre, the turbocharging being part of the problem. The 8th Air Force, being so dissatisfied with the aircraft, gave Rolls Royce a 38 to be fitted fitted with Merlins as a test to over come the short falls, but a stop was put to the exercise by Washington, presumably for political/industrial reasons ie leaving Allison without work. The 8th in any event got rid of the 38.
The Comet used a NACA 63A116 at the root and a NACA 63A112 at the tip. Hence not symmetrical, I'd be interested in any reference that says otherwise.
barit, re the turbocharging and laminar flow I put up the B-24. The Davis airfoil was adopted by Consolidated because of its advanced properties, but at the time they were not aware that those properties came because of its laminar flow. The P-51 generally takes the prize as the first laminar, but that may be qualified by being the first purpose designed laminar. Bit like Yeager being the first to crack the barrier, not really, George Welch in the F-86 beat him to it by two weeks. The difference was Welch did it in a dive whereas Yeager did it in level flight. Again politics were heavily involved in the claim that Yeager was first.
The Comet used a NACA 63A116 at the root and a NACA 63A112 at the tip. Hence not symmetrical, I'd be interested in any reference that says otherwise.
barit, re the turbocharging and laminar flow I put up the B-24. The Davis airfoil was adopted by Consolidated because of its advanced properties, but at the time they were not aware that those properties came because of its laminar flow. The P-51 generally takes the prize as the first laminar, but that may be qualified by being the first purpose designed laminar. Bit like Yeager being the first to crack the barrier, not really, George Welch in the F-86 beat him to it by two weeks. The difference was Welch did it in a dive whereas Yeager did it in level flight. Again politics were heavily involved in the claim that Yeager was first.
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The Comet used a NACA 63A116 at the root and a NACA 63A112 at the tip. Hence not symmetrical, I'd be interested in any reference that says otherwise.
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Serendipity
Brian Abraham:
Fascinating. Laminar flow via serendipity.
30s race pilot and designer Ben Howard observed a racing Monocoupe (from the wrong end, as he tells it) and deduced the reason for its efficiency and success - and capitalized on that observation when he built his hugely successful DGA-6.
Monocoupe, in the meantime proved Howard right and themselves wrong by diverging from their winning formula; their earlier design success was pure serendipity (no disturbances in the downwash from the wing upper surface).
The Davis airfoil was adopted by Consolidated because of its advanced properties, but at the time they were not aware that those properties came because of its laminar flow.
30s race pilot and designer Ben Howard observed a racing Monocoupe (from the wrong end, as he tells it) and deduced the reason for its efficiency and success - and capitalized on that observation when he built his hugely successful DGA-6.
Monocoupe, in the meantime proved Howard right and themselves wrong by diverging from their winning formula; their earlier design success was pure serendipity (no disturbances in the downwash from the wing upper surface).
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Brian
One rarely hears that story. I have been privileged to meet and speak with the General. Obviously, he takes no pleasure in discussing even Welch's grape juice, let alone the X86.
One believes The AAC could have found a more likable first M guy. Yeager is a caricature of himself, arrogant, dismissive and uncomfortable to be around. It is pretty cool to watch him take off in his friend Bart's Husky each Saturday morning, but really, not too many people like to be around him. He is in better mettle when he is paid to be nice. (He demands money to meet people). Then again, our encounter was free, perhaps that is why he was such an a*****e.
bear
One rarely hears that story. I have been privileged to meet and speak with the General. Obviously, he takes no pleasure in discussing even Welch's grape juice, let alone the X86.
One believes The AAC could have found a more likable first M guy. Yeager is a caricature of himself, arrogant, dismissive and uncomfortable to be around. It is pretty cool to watch him take off in his friend Bart's Husky each Saturday morning, but really, not too many people like to be around him. He is in better mettle when he is paid to be nice. (He demands money to meet people). Then again, our encounter was free, perhaps that is why he was such an a*****e.
bear
Barit1 & Brian
If you read your Fate is the Hunter, you will find all were not happy with the Davis wing. Gann reports it couldn't "carry enough ice to chill a highball" which was a problem for C-87 ops. It was a good airfoil for high altitude bombing and the like, though.
Bear--that is his unfortunate reputation within the AF. I thought his book for outrageous bollocks-self-referential to an extreme.
GF
If you read your Fate is the Hunter, you will find all were not happy with the Davis wing. Gann reports it couldn't "carry enough ice to chill a highball" which was a problem for C-87 ops. It was a good airfoil for high altitude bombing and the like, though.
Bear--that is his unfortunate reputation within the AF. I thought his book for outrageous bollocks-self-referential to an extreme.
GF
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Some faster airplanes had symmetrical wings, I'd guess the F-104 was one. Not sure about FD2, Bristol 188, Bristol 221. And aren't helicopter blades symmetrical?
edit - interesting to use barit1's list and search for 'biconvex', that finds quite a few more symmetricals
.
AerMacchi MC.72 - Schneider Trophy racing seaplane (1931)
AerMacchi M.67- Schneider Trophy racing seaplane (1929)
AIDC Ching-Kuo IDF - Indigenous Defence Fighter (1989)
Albert A-10 - Possibly (1926-33)
Breda 19 - Biplane Fighter (1928)
Bristol 188 - Stainless Steel twin (1982)
Canadair CL-201 CF-104
Canadair CL-90 CF-104
Focke Wulf A43 Falke - Light utility Monoplane (1932)
Handley Page HP.115 - High sweep delta (1961)
Helewan HA-300 - Egyptian fighter (1964)
Leduc O.21 - French ramjet (1947)
Lockheed 246 F-104 - (1954)
Lockheed XQ-5 - M4.3 drone (1951)
Lockheed X-27 Lancer - not flown
Lockheed X-7 - ramjet flying testbed (1951)
Miles Gillette Falcon - modified M3B (1946)
Miles M.52 - supersonic research aircraft (not flown)
Nord CT.41 PQM-56A - M3.1 target drone (1959)
Renard R.31 - Belgian parasol monoplane (1932)
Republic AN/USD-4 - not known, possibly drone
.
The Albert TE-1 dates from 1926 and the Albert A-20 is from 1933 so presumably the Albert A-10 is from the same era. The Breda 19 is contemporary and the Aermacchi Schneider Trophy planes a little later. Possibly other Schneider Trophy planes may also have symmetrical airfoils.
.
Our neighbour who was an eminent Bristol Engines man bought a car for his wife and occasionally drove it to work with a broad grin on his face. It was a little green Hillman Imp with the Bristol registration WHY188.
.
edit - interesting to use barit1's list and search for 'biconvex', that finds quite a few more symmetricals
.
AerMacchi MC.72 - Schneider Trophy racing seaplane (1931)
AerMacchi M.67- Schneider Trophy racing seaplane (1929)
AIDC Ching-Kuo IDF - Indigenous Defence Fighter (1989)
Albert A-10 - Possibly (1926-33)
Breda 19 - Biplane Fighter (1928)
Bristol 188 - Stainless Steel twin (1982)
Canadair CL-201 CF-104
Canadair CL-90 CF-104
Focke Wulf A43 Falke - Light utility Monoplane (1932)
Handley Page HP.115 - High sweep delta (1961)
Helewan HA-300 - Egyptian fighter (1964)
Leduc O.21 - French ramjet (1947)
Lockheed 246 F-104 - (1954)
Lockheed XQ-5 - M4.3 drone (1951)
Lockheed X-27 Lancer - not flown
Lockheed X-7 - ramjet flying testbed (1951)
Miles Gillette Falcon - modified M3B (1946)
Miles M.52 - supersonic research aircraft (not flown)
Nord CT.41 PQM-56A - M3.1 target drone (1959)
Renard R.31 - Belgian parasol monoplane (1932)
Republic AN/USD-4 - not known, possibly drone
.
The Albert TE-1 dates from 1926 and the Albert A-20 is from 1933 so presumably the Albert A-10 is from the same era. The Breda 19 is contemporary and the Aermacchi Schneider Trophy planes a little later. Possibly other Schneider Trophy planes may also have symmetrical airfoils.
.
Our neighbour who was an eminent Bristol Engines man bought a car for his wife and occasionally drove it to work with a broad grin on his face. It was a little green Hillman Imp with the Bristol registration WHY188.
.
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you will find all were not happy with the Davis wing
Iron Duck, the aerofoil was modified later with a leading edge droop following the accidents, but the base aerofoil was still asymmetrical.
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mike wsm
The F-104 is an odd duck. When looking down the wing tip, Tank removed, the wing shows a definite symmetry top/bottom. the deal is, it is shaped like a noodle. It is "S" shaped, a cuff-like (droop) leading edge, an up swoop, a down, then straight at the TE.
I have not researched this, I more or less think Kelly Johnson did no wrong. No one I know calls it a fighter, it is an interceptor, very big difference. Up Kill Down.
The F-104 is an odd duck. When looking down the wing tip, Tank removed, the wing shows a definite symmetry top/bottom. the deal is, it is shaped like a noodle. It is "S" shaped, a cuff-like (droop) leading edge, an up swoop, a down, then straight at the TE.
I have not researched this, I more or less think Kelly Johnson did no wrong. No one I know calls it a fighter, it is an interceptor, very big difference. Up Kill Down.
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Brian Abraham
Just to be clear, Consolidated didn't know, or did David R. Davis not know?
barit1
You mean he produced an airfoil similar to the p-51 (with the crest further aft than usual)?
bearfoil
Can you post a picture?
The Davis airfoil was adopted by Consolidated because of its advanced properties, but at the time they were not aware that those properties came because of its laminar flow.
barit1
30s race pilot and designer Ben Howard observed a racing Monocoupe (from the wrong end, as he tells it) and deduced the reason for its efficiency and success - and capitalized on that observation when he built his hugely successful DGA-6
bearfoil
The F-104 is an odd duck. When looking down the wing tip, Tank removed, the wing shows a definite symmetry top/bottom. the deal is, it is shaped like a noodle. It is "S" shaped, a cuff-like (droop) leading edge, an up swoop, a down, then straight at the TE.
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You mean he produced an airfoil similar to the p-51 (with the crest further aft than usual)?
The Howard DGA-6 was the only purpose-built racer to evolve into a successful series of commercial designs.