The Wright brothers just glided in 1903. They flew in 1908.
Not a problem with Maxim.
Spent a day in South Kensington in the Science Museum with Haraka Snr. in 1979 measuring and profiling up one of the props off of his machine.
Great fun, way up on ladders over the entrance to the aviation gallery, measuring up all the stations!
Spent a day in South Kensington in the Science Museum with Haraka Snr. in 1979 measuring and profiling up one of the props off of his machine.
Great fun, way up on ladders over the entrance to the aviation gallery, measuring up all the stations!
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I recall that the Science Museum in London was also involved in controversy over the Wright Brothers, but I cannot remember details. In those days the US Patent Office had VERY different standards and practices to what we would expect today, and Edison was one of many people who was able to exploit this to enormous personal gain.
I am naturally suspicious of any attempt to revise history and accepted wisdom, but I do have significant doubts about the the Wright Brothers claim.
I am naturally suspicious of any attempt to revise history and accepted wisdom, but I do have significant doubts about the the Wright Brothers claim.
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The much celebrated 66% efficiency of the 1903 propellers not confirmed by wind tunnel tests
http://www.wrightexperience.com/indepth/pdfs/props.pdf
A pity you don't understand what is written in the references you yourself use, which says
These data show that the 1903 Wright propeller had a maximum efficiency of 82 percent.
Based on Wilbur Wright's notes on the fourth flight of Dec. 17, 1903, the Flyer had an estimated forward speed of 31 mph during the steady flight portion of its path and the propellers were turning at 379 rpm, which yields an advance ratio of 0.85. Hence, the 1903 Wright propellers were operating at a mechanical efficiency of slightly over 75 percent during steady flight.
Based on Wilbur Wright's notes on the fourth flight of Dec. 17, 1903, the Flyer had an estimated forward speed of 31 mph during the steady flight portion of its path and the propellers were turning at 379 rpm, which yields an advance ratio of 0.85. Hence, the 1903 Wright propellers were operating at a mechanical efficiency of slightly over 75 percent during steady flight.
Last edited by Brian Abraham; 29th May 2014 at 09:50.
There are obviously many people around with a personal ax(e) to grind vis a vis the Wright Brothers.
I really do not think that the Wrights claimed to be first at anything,sure they filed patents and also probably made themselves unpopular with quite a few people with the legal wrangles - but I do not think there is much doubt about who tackled the question of powered flight in a structured and 'scientific' way.
I personally would not use journalistic articles as a primary source for anything - even after over 100 years of flight they still very rarely get anything correct.
As to 'proving' anything - I cannot do it from where I am at present - and I am always cautious about using internet articles as any Tom,Dick or Harry can write articles claiming it to be the 'truth' (as can be seen by the 2 main doubters on here !)
Were the Wrights perfect ? -No (who is?)
Were the Wrights liars ? ...... I doubt it !
I have been involved in aviation for over 40 years and I see no reason to doubt much about the Wrights 1903 or 1905 flights - they never tried to hide the damage caused during the landing in 1903 and also admitted that the aircraft was unstable in pitch...which is why they redesigned it for 1905...as I said previously - that is development !!
If one reads carefully - the dec 17 flights were on fairly flat ground and not as the op claimed 'glided'...sure they were a little short of power - and as to copying or looking at others engines - there is no reason to reinvent the wheel - technical details are 'copied' much of the time but in the wrights case they would have been dumb not to look at others engines if given the opportunity.Just to be able to design and build a fairly lightweight engine giving 12 hp in 1903 was clever enough !
I really do not think that the Wrights claimed to be first at anything,sure they filed patents and also probably made themselves unpopular with quite a few people with the legal wrangles - but I do not think there is much doubt about who tackled the question of powered flight in a structured and 'scientific' way.
I personally would not use journalistic articles as a primary source for anything - even after over 100 years of flight they still very rarely get anything correct.
As to 'proving' anything - I cannot do it from where I am at present - and I am always cautious about using internet articles as any Tom,Dick or Harry can write articles claiming it to be the 'truth' (as can be seen by the 2 main doubters on here !)
Were the Wrights perfect ? -No (who is?)
Were the Wrights liars ? ...... I doubt it !
I have been involved in aviation for over 40 years and I see no reason to doubt much about the Wrights 1903 or 1905 flights - they never tried to hide the damage caused during the landing in 1903 and also admitted that the aircraft was unstable in pitch...which is why they redesigned it for 1905...as I said previously - that is development !!
If one reads carefully - the dec 17 flights were on fairly flat ground and not as the op claimed 'glided'...sure they were a little short of power - and as to copying or looking at others engines - there is no reason to reinvent the wheel - technical details are 'copied' much of the time but in the wrights case they would have been dumb not to look at others engines if given the opportunity.Just to be able to design and build a fairly lightweight engine giving 12 hp in 1903 was clever enough !
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The case of Gustav Whitehead as the first man to fly a powered plane is hopeless. His propellers had an efficiency of 237%! Impossible!
By applying the well known relation:
Efficiency_propellers = Thrust_propellers * Speed_plane / Power_engine
to the particular parameters of Gustav Whitehead's alleged No. 22 airplane:
- max_Thrust_propellers = 508 pounds
- Speed_plane = 70 miles/hour
- Power_engine = 40 HP
(read the article "The Whitehead Flying Machine" (attached) )
the efficiency of the propellers results as being 237%. Impossible! Case closed!
Demonstration:
508pounds * 70miles/hour / 40HP = 237%
-----------------------------------------------------------------------------------------------
"American Inventor Magazine, 1 April 1902
The Whitehead Flying Machine
Has the End been Finally Attained, and is the Dirigible Balloon to Go?
Editor, American Inventor
Dear Sir: Replying to your recent letter, I take pleasure in sending you the following description of my flying machine No. 22, the latest that I have constructed:
This machine was built in four months with the aid of 14 skilled mechanics and cost about $1,700 to build. It is run by a 40 horse-power kerosene motor of my own design, especially constructed for strength, power and lightness, weighing but 120 pounds complete. It will run for a week at a time if required, without running hot, stopping, or in any possible manner troubling the operator. No electrical apparatus is required for ignition purposes. Ignition is accomplished by its own heat and compression; it runs about 800 revolutions per minute, has five cylinders and no fly-wheel is used. It requires a space 10 inches wide, 4 feet long and 10 inches high.
The flying machine proper is built like my machine No. 21. of which I send you photographs, only instead of using acetylene gas for driving purposes I use the kerosene motor described above. Machine No. 22 is made mostly of steel and aluminum. There is a body 10 feet long, 3-1/2 feet wide and 3-1/2 feet deep, shaped like a fish, and resting on four automobile wheels, 13 inches in diameter. While standing on the ground the two front wheels are connected to the kerosene motor and the rear wheels are used for steering. They can be easily moved by the aeronaut. The body is well stayed with steel tubing and braced with steel piano wire. It is covered with aluminum sheeting and made so it will float like a boat in the water. On either side are large wings or aeroplanes shaped like the wings of a flying fish or bat. The ribs are of steel tubing in No. 22 instead of bamboo as in No. 21 machine, and are covered with 450 square feet of the best silk obtainable. In front of the wings and across the body is a steel framework to which is connected the propellers for driving the machine through the air. The propellers are 6 feet in diameter and have a projecting blade-surface of 4 square feet each. They are made of wood and are covered with very thin aluminum sheeting. The propellers run about 600 revolutions per minute under full power and turn in opposite directions. When running at full speed they will exert a thrust of 508 pounds. I measured this thrust by attaching the machine to a post by means of a dynamometer and running the engines at full speed. There is a mast and a bowsprit braced something like a ship's rigging to hold all parts in their proper relations to each other. In the stern of the machine there is a 12-foot tail, something similar to a bird's tail, which, like the wings, can be folded up in half a minute and laid against the sides of the body. An automatic apparatus serves to keep the equilibrium in the air.
This is illustrated in the diagrams, in which similar letters refer to similar parts in both the top and side views. H is the body of the machine containing the motor (not shown), and the wheels, II, on which it rests on the ground and supporting the tail, K. F is the bowsprit on which is mounted the lever C, supporting the small aeroplane E. The lever C is connected by the rod G to the pendulum B, which has at its lower end the weight A. It is obvious that the weight A will tilt the aeroplane E if the machine drops her bow. The leverage gained from the end of the bowsprit to the center of the machine is so great that the least change in the position of the aeroplane is instantly effective. By means of the handle D, such changes are under the immediate control of the aeronaut. I have not shown the wings in these diagrams.
In order to start flying, the motor is set in motion, and then connected to the front wheels which drive the machine forward at fearful speed. When ready to go up, a spring is released which stretches the wings and the propellers are started by means of a lever which stops the ground wheels and turns the power into the propellers. It takes about 20 yards run with the extra weight of a man (about 180 pounds) before the machine leaves the ground.
This new machine has been tried twice, on January 17, 1902. It was intended to fly only short distances, but the machine behaved so well that at the first trial it covered nearly two miles over the water of Long Island Sound, and settled in the water without mishap to either machine or operator. It was then towed back to the starting place. On the second trial it started from the same place and sailed with myself on board across Long Island Sound. The machine kept on steadily in crossing the wind at a height of about 200 feet, when it came into my mind to try steering around in a circle. As soon as I turned the rudder and drove one propeller faster than the other the machine turned a bend and flew north with the wind at a frightful speed, but turned steadily around until I saw the starting place in the distance. I continued to turn but when near the land again, I slowed up the propellers and sank gently down on an even keel into the water, she readily floating like a boat. My men then pulled her out of the water, and as the day was at a close and the weather changing for the worse. I decided to take her home until Spring.
The length of flight on the first trial was about two miles, and on the second about seven miles. The last trial was a circling flight, and as I successfully returned to my starting place with a machine hitherto untried and heavier than the air, I consider the trip quite a success. To my knowledge it is the first of its kind. This matter has so far never been published.
I have no photographs taken yet of No. 22, but send you some of No. 21, as these machines are exactly alike, except the details mentioned. No. 21 has made four trips, the longest one and a half miles, on August 14. 1901. The wings of both machines measure 30 feet from tip to tip, and the length of the entire machine is 32 feet. It will run on the ground 50 miles an hour, and in air travel at about 70 miles. I believe that if wanted it would fly 100 miles an hour. The power carried is considerably more than necessary.
Believing with Maxim that the future of the air machine lies in an apparatus made without the gas bag, I have taken up the aeroplane, and will stick to it until I have succeeded completely or expire in the attempt of so doing.
As soon as I get my machine out this Spring I will let you know. To describe the feeling of flying is almost impossible, for. in fact, a man is more frightened than anything else.
Trusting this will interest your readers, I remain, Very truly yours,
Gustave Whitehead
Bridgeport, Conn.
The Editor, hardly able to credit the account above given that a man has actually succeeded in flying: in a machine heavier than air, wrote again to Mr. Whitehead for confirmation. Mr. Whitehead's reply follows.
Editor, American Inventor
Dear Sir: Yours of the 20th received. Yes, it was a full-sized flying machine, and I, myself, flew seven miles and returned to my starting point.
In both the flights described in my previous letter, I flew in the machine myself. This, of course, is new to the world at large, but I do not care much in being advertised except by a good paper like yours. Such accounts may help others along who are working in the same line. As soon as I can I shall try again. This coming spring I will have photographs made of machine No. 22 in the air and let you have pictures taken during its flight. If you can come up and get them yourself, so much the better. I attempted this before, but in the first trial the weather was bad, some little rain and a very cloudy sky, and the snapshots that were taken did not come out right. I cannot take any time exposures of the machine when in flight on account of its high speed.
I enclose a small sketch showing the course the machine made in her longest flight. January 17. 1902.
Trusting this will be satisfactory, I remain, yours truly.
GUSTAVE WHITEHEAD
Bridgeport, Conn.
Newspaper readers will remember several accounts of Mr. Whitehead's performances last summer. Probably most people put them down as fakes, but it seems as though the long-sought answer to the most difficult problem Nature ever put to man is gradually coming in sight. The Editor and the readers of these columns await with interest the promised photographs of the machine in the air. The similarity of this machine to Langley's experimental flying machine is well shown in the accompanying illustration, reprinted from a previous issue. Mr. Langley, it will be remembered, was the first to demonstrate the possibility of mechanical flight. Ed."
Source: Whitehead News Articles
Original article:
"The Whitehead Flying Machine", American Inventor Magazine, 1 April 1902
First page) http://www.wright-brothers.org/Histo...e-No-22-p1.jpg
Second page) http://www.wright-brothers.org/Histo...e-No-22-p2.jpg
By applying the well known relation:
Efficiency_propellers = Thrust_propellers * Speed_plane / Power_engine
to the particular parameters of Gustav Whitehead's alleged No. 22 airplane:
- max_Thrust_propellers = 508 pounds
- Speed_plane = 70 miles/hour
- Power_engine = 40 HP
(read the article "The Whitehead Flying Machine" (attached) )
the efficiency of the propellers results as being 237%. Impossible! Case closed!
Demonstration:
508pounds * 70miles/hour / 40HP = 237%
-----------------------------------------------------------------------------------------------
"American Inventor Magazine, 1 April 1902
The Whitehead Flying Machine
Has the End been Finally Attained, and is the Dirigible Balloon to Go?
Editor, American Inventor
Dear Sir: Replying to your recent letter, I take pleasure in sending you the following description of my flying machine No. 22, the latest that I have constructed:
This machine was built in four months with the aid of 14 skilled mechanics and cost about $1,700 to build. It is run by a 40 horse-power kerosene motor of my own design, especially constructed for strength, power and lightness, weighing but 120 pounds complete. It will run for a week at a time if required, without running hot, stopping, or in any possible manner troubling the operator. No electrical apparatus is required for ignition purposes. Ignition is accomplished by its own heat and compression; it runs about 800 revolutions per minute, has five cylinders and no fly-wheel is used. It requires a space 10 inches wide, 4 feet long and 10 inches high.
The flying machine proper is built like my machine No. 21. of which I send you photographs, only instead of using acetylene gas for driving purposes I use the kerosene motor described above. Machine No. 22 is made mostly of steel and aluminum. There is a body 10 feet long, 3-1/2 feet wide and 3-1/2 feet deep, shaped like a fish, and resting on four automobile wheels, 13 inches in diameter. While standing on the ground the two front wheels are connected to the kerosene motor and the rear wheels are used for steering. They can be easily moved by the aeronaut. The body is well stayed with steel tubing and braced with steel piano wire. It is covered with aluminum sheeting and made so it will float like a boat in the water. On either side are large wings or aeroplanes shaped like the wings of a flying fish or bat. The ribs are of steel tubing in No. 22 instead of bamboo as in No. 21 machine, and are covered with 450 square feet of the best silk obtainable. In front of the wings and across the body is a steel framework to which is connected the propellers for driving the machine through the air. The propellers are 6 feet in diameter and have a projecting blade-surface of 4 square feet each. They are made of wood and are covered with very thin aluminum sheeting. The propellers run about 600 revolutions per minute under full power and turn in opposite directions. When running at full speed they will exert a thrust of 508 pounds. I measured this thrust by attaching the machine to a post by means of a dynamometer and running the engines at full speed. There is a mast and a bowsprit braced something like a ship's rigging to hold all parts in their proper relations to each other. In the stern of the machine there is a 12-foot tail, something similar to a bird's tail, which, like the wings, can be folded up in half a minute and laid against the sides of the body. An automatic apparatus serves to keep the equilibrium in the air.
This is illustrated in the diagrams, in which similar letters refer to similar parts in both the top and side views. H is the body of the machine containing the motor (not shown), and the wheels, II, on which it rests on the ground and supporting the tail, K. F is the bowsprit on which is mounted the lever C, supporting the small aeroplane E. The lever C is connected by the rod G to the pendulum B, which has at its lower end the weight A. It is obvious that the weight A will tilt the aeroplane E if the machine drops her bow. The leverage gained from the end of the bowsprit to the center of the machine is so great that the least change in the position of the aeroplane is instantly effective. By means of the handle D, such changes are under the immediate control of the aeronaut. I have not shown the wings in these diagrams.
In order to start flying, the motor is set in motion, and then connected to the front wheels which drive the machine forward at fearful speed. When ready to go up, a spring is released which stretches the wings and the propellers are started by means of a lever which stops the ground wheels and turns the power into the propellers. It takes about 20 yards run with the extra weight of a man (about 180 pounds) before the machine leaves the ground.
This new machine has been tried twice, on January 17, 1902. It was intended to fly only short distances, but the machine behaved so well that at the first trial it covered nearly two miles over the water of Long Island Sound, and settled in the water without mishap to either machine or operator. It was then towed back to the starting place. On the second trial it started from the same place and sailed with myself on board across Long Island Sound. The machine kept on steadily in crossing the wind at a height of about 200 feet, when it came into my mind to try steering around in a circle. As soon as I turned the rudder and drove one propeller faster than the other the machine turned a bend and flew north with the wind at a frightful speed, but turned steadily around until I saw the starting place in the distance. I continued to turn but when near the land again, I slowed up the propellers and sank gently down on an even keel into the water, she readily floating like a boat. My men then pulled her out of the water, and as the day was at a close and the weather changing for the worse. I decided to take her home until Spring.
The length of flight on the first trial was about two miles, and on the second about seven miles. The last trial was a circling flight, and as I successfully returned to my starting place with a machine hitherto untried and heavier than the air, I consider the trip quite a success. To my knowledge it is the first of its kind. This matter has so far never been published.
I have no photographs taken yet of No. 22, but send you some of No. 21, as these machines are exactly alike, except the details mentioned. No. 21 has made four trips, the longest one and a half miles, on August 14. 1901. The wings of both machines measure 30 feet from tip to tip, and the length of the entire machine is 32 feet. It will run on the ground 50 miles an hour, and in air travel at about 70 miles. I believe that if wanted it would fly 100 miles an hour. The power carried is considerably more than necessary.
Believing with Maxim that the future of the air machine lies in an apparatus made without the gas bag, I have taken up the aeroplane, and will stick to it until I have succeeded completely or expire in the attempt of so doing.
As soon as I get my machine out this Spring I will let you know. To describe the feeling of flying is almost impossible, for. in fact, a man is more frightened than anything else.
Trusting this will interest your readers, I remain, Very truly yours,
Gustave Whitehead
Bridgeport, Conn.
The Editor, hardly able to credit the account above given that a man has actually succeeded in flying: in a machine heavier than air, wrote again to Mr. Whitehead for confirmation. Mr. Whitehead's reply follows.
Editor, American Inventor
Dear Sir: Yours of the 20th received. Yes, it was a full-sized flying machine, and I, myself, flew seven miles and returned to my starting point.
In both the flights described in my previous letter, I flew in the machine myself. This, of course, is new to the world at large, but I do not care much in being advertised except by a good paper like yours. Such accounts may help others along who are working in the same line. As soon as I can I shall try again. This coming spring I will have photographs made of machine No. 22 in the air and let you have pictures taken during its flight. If you can come up and get them yourself, so much the better. I attempted this before, but in the first trial the weather was bad, some little rain and a very cloudy sky, and the snapshots that were taken did not come out right. I cannot take any time exposures of the machine when in flight on account of its high speed.
I enclose a small sketch showing the course the machine made in her longest flight. January 17. 1902.
Trusting this will be satisfactory, I remain, yours truly.
GUSTAVE WHITEHEAD
Bridgeport, Conn.
Newspaper readers will remember several accounts of Mr. Whitehead's performances last summer. Probably most people put them down as fakes, but it seems as though the long-sought answer to the most difficult problem Nature ever put to man is gradually coming in sight. The Editor and the readers of these columns await with interest the promised photographs of the machine in the air. The similarity of this machine to Langley's experimental flying machine is well shown in the accompanying illustration, reprinted from a previous issue. Mr. Langley, it will be remembered, was the first to demonstrate the possibility of mechanical flight. Ed."
Source: Whitehead News Articles
Original article:
"The Whitehead Flying Machine", American Inventor Magazine, 1 April 1902
First page) http://www.wright-brothers.org/Histo...e-No-22-p1.jpg
Second page) http://www.wright-brothers.org/Histo...e-No-22-p2.jpg
Last edited by simplex1; 29th May 2014 at 10:52.
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In the article, Evolution of Wright Flyer Propellers between 1903 and 1912
By Robert L. Ash, Stanley J. Miley, Drew Landman (see http://www.wrightexperience.com/indepth/pdfs/props.pdf ), the authors, components of the Wright Experience team that replicated Flyer I 1903, wrote:
"However, their methodology is not even mentioned in contemporary literature, even though they (the Wright brothers) were achieving propeller performance levels by 1905 that were only achieved by others after World War I."
The citation is another argument the two brothers lied about the performance of their 1903 - 1905 propellers as long as after Aug. 8, 1908 their planes and propellers became known, they even started to sell them. Despite many plane builders being able to study these miraculous propellers nobody was able to replicate their claimed high efficiency till after WWI! This is ridiculous.
By Robert L. Ash, Stanley J. Miley, Drew Landman (see http://www.wrightexperience.com/indepth/pdfs/props.pdf ), the authors, components of the Wright Experience team that replicated Flyer I 1903, wrote:
"However, their methodology is not even mentioned in contemporary literature, even though they (the Wright brothers) were achieving propeller performance levels by 1905 that were only achieved by others after World War I."
The citation is another argument the two brothers lied about the performance of their 1903 - 1905 propellers as long as after Aug. 8, 1908 their planes and propellers became known, they even started to sell them. Despite many plane builders being able to study these miraculous propellers nobody was able to replicate their claimed high efficiency till after WWI! This is ridiculous.
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max_Thrust_propellers = 508 pounds
- Speed_plane = 70 miles/hour
- Power_engine = 40 HP
the efficiency of the propellers results as being 237%. Impossible! Case closed!
- Speed_plane = 70 miles/hour
- Power_engine = 40 HP
the efficiency of the propellers results as being 237%. Impossible! Case closed!
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Brian Abraham,
The propellers the Wright brothers said they had built in 1903 should have had an efficiency a bit over 75% to keep "Flyer I 1903" aloft during flight No. 4 on Dec. 17, 1903. This come in contradiction with the 66% efficient propellers the brothers claimed they had used in 1903. This is one discrepancy noticed by the team "Wright Experience"!
Another problem, I already mentioned, is that the efficiency obtained by the Wright Experience, for the alleged 1903 66% efficient propellers, varied between 75% and 82%. The team could not get that 66%.
"These data (the experiments done by the team Wright Experience) show that the 1903 Wright propeller had a maximum efficiency of 82 percent.
Based on Wilbur Wright's notes on the fourth flight of Dec. 17, 1903, the Flyer had an estimated forward speed of 31 mph during the steady flight portion of its path and the propellers were turning at 379 rpm, which yields an advance ratio of 0.85. Hence, the 1903 Wright propellers were operating at a mechanical efficiency of slightly over 75 percent during steady flight.
This was a remarkable feat, considering the state of propeller knowledge prior to World War I.
Since Wilbur estimated their propeller performance to be 66 percent in March of 1903, we found the results of our experimental tests to be quite surprising."
Source: (The Wright Experience; By Robert L. Ash, Colin P. Britcher, and Kenneth W. Hyde, Mechanical Engineering "100 Years of Flight" supplement, Dec. 2003 -- "Prop-Wrights," Feature Article )
The propellers the Wright brothers said they had built in 1903 should have had an efficiency a bit over 75% to keep "Flyer I 1903" aloft during flight No. 4 on Dec. 17, 1903. This come in contradiction with the 66% efficient propellers the brothers claimed they had used in 1903. This is one discrepancy noticed by the team "Wright Experience"!
Another problem, I already mentioned, is that the efficiency obtained by the Wright Experience, for the alleged 1903 66% efficient propellers, varied between 75% and 82%. The team could not get that 66%.
"These data (the experiments done by the team Wright Experience) show that the 1903 Wright propeller had a maximum efficiency of 82 percent.
Based on Wilbur Wright's notes on the fourth flight of Dec. 17, 1903, the Flyer had an estimated forward speed of 31 mph during the steady flight portion of its path and the propellers were turning at 379 rpm, which yields an advance ratio of 0.85. Hence, the 1903 Wright propellers were operating at a mechanical efficiency of slightly over 75 percent during steady flight.
This was a remarkable feat, considering the state of propeller knowledge prior to World War I.
Since Wilbur estimated their propeller performance to be 66 percent in March of 1903, we found the results of our experimental tests to be quite surprising."
Source: (The Wright Experience; By Robert L. Ash, Colin P. Britcher, and Kenneth W. Hyde, Mechanical Engineering "100 Years of Flight" supplement, Dec. 2003 -- "Prop-Wrights," Feature Article )
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is that the efficiency obtained by the Wright Experience, for the alleged 1903 66% efficient propellers, varied between 75% and 82%. The team could not get that 66%.
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"- max_Thrust_propellers = 508 pounds
- Speed_plane = 70 miles/hour
- Power_engine = 40 HP
the efficiency of the propellers results as being 237%. Impossible! Case closed!"
Comment by Brian Abraham,
You got those numbers so wrong as to be laughable, and I'm not giving you the correct figures. Hint - Attend a physics lesson and learn the correct formula.
- Speed_plane = 70 miles/hour
- Power_engine = 40 HP
the efficiency of the propellers results as being 237%. Impossible! Case closed!"
Comment by Brian Abraham,
You got those numbers so wrong as to be laughable, and I'm not giving you the correct figures. Hint - Attend a physics lesson and learn the correct formula.
My calculations are correct!
Here you find the formula I applied:
Propeller Performance: An introduction, by EPI Inc.
Of course I transformed the thrust from pounds to newtons, the speed from miles/hour to meters/second and the power from horsepower to watts. Of course I did not do 508*70/40 = 889! Because this is what you believe I did. You should have calculated first to convince yourself my 237% efficiency is correctly obtained, based exactly on the data provided by Gustave Whitehead, and it proves he lied about his flights on Jan. 17, 1902.
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What don't you understand? The Wrights figured 66%, yet the team achieved 75 - 82. When I did maths 75 - 82 was greater than 66. That is, the props were more efficient than the Wrights believed with their 66%.
In the article "The Wright Brothers' Aeroplane, O. and W. Wright, The Century Magazine, September 1908, pag. 648-649, The Wright Brothers' Aeroplane [Orville and Wilbur Wright, The Century Magazine, September 1908] | Library of Congress ", the Wright brothers wrote:
"Our first propellers, built entirely from calculations, gave in useful work 66 per cent. of the power expended. This was about one third more than had been secured by Maxim or Langley."
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simplex 1 said: The propellers the Wright brothers said they had built in 1903 should have had an efficiency a bit over 75% to keep "Flyer I 1903" aloft during flight No. 4 on Dec. 17, 1903. This come in contradiction with the 66% efficient propellers the brothers claimed they had used in 1903. This is one discrepancy noticed by the team "Wright Experience"!
Another problem, I already mentioned, is that the efficiency obtained by the Wright Experience, for the alleged 1903 66% efficient propellers, varied between 75% and 82%. The team could not get that 66%.
Another problem, I already mentioned, is that the efficiency obtained by the Wright Experience, for the alleged 1903 66% efficient propellers, varied between 75% and 82%. The team could not get that 66%.
Even if it's true that the Wright brothers estimated that their propellers are 66% efficient, when in fact they were 75% efficient, why doesn't this simply suggest that they were a little off on their 66% estimate or in any one of their underlying estimates re speed or RPMs.
With all due respect, this is evidence of your current bias, not evidence of anything sinister from 110 years ago.
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Efficiency_propellers = Thrust_propellers * Speed_plane / Power_engine
My calculations are correct!
Here you find the formula I applied:
Propeller Performance: An introduction, by EPI Inc.
Here you find the formula I applied:
Propeller Performance: An introduction, by EPI Inc.
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Even if it's true that the Wright brothers estimated that their propellers are 66% efficient, when in fact they were 75% efficient, why doesn't this simply suggest that they were a little off on their 66% estimate or in any one of their underlying estimates re speed or RPMs.
http://www.pprune.org/aviation-histo...ml#post8498210
Do I have to repeat 100 times that the Wright brothers claimed they had obtained 66% efficient propellers, they built them at this efficiency. They did not just estimate a 66% efficiency for their propellers!
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Your calculations are incorrect because you are not using the correct formula, even though your reference gives the correct information.
Unless you prove the propellers of Whitehead increased their thrust at least 2.37 times at 70 mile/hour as compared to the static thrust your accusations are baseless.
The dynamic thrust for the same engine power can increase a bit as the plane gain speed but not 237%.
"Static Thrust of Propellers
The thrust of a propeller is not constant for different flight speeds. Reducing the inflow velocity generally increases the thrust. A reduction of the aircraft speed down to zero tends to increase the thrust even further, but often a rapid loss of thrust can be observed in this regime."
Source: Static Thrust of Propellers
Why all this activity across different forums ?
Somebody writing a book ?
I am still laughing at the idea of putting a propeller under the aircraft to help it stay airborne
Somebody writing a book ?
I am still laughing at the idea of putting a propeller under the aircraft to help it stay airborne
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Please read again my post from here:
The Wright brothers just glided in 1903. They flew in 1908.
Do I have to repeat 100 times that the Wright brothers claimed they had obtained 66% efficient propellers, they built them at this efficiency. They did not just estimate a 66% efficiency for their propellers!
The Wright brothers just glided in 1903. They flew in 1908.
Do I have to repeat 100 times that the Wright brothers claimed they had obtained 66% efficient propellers, they built them at this efficiency. They did not just estimate a 66% efficiency for their propellers!
Quote
I am still laughing at the idea of putting a propeller under the aircraft to help it stay airborne
Almost as ridiculous as hanging the whole machine from a large propellor and leaving the wings off.
I was not going to get involved in this long and largely impossible thread, so I shall just say that if the OP really believes that propellor thrust does not vary with speed that is his/her own problem and we may as well give up trying to use engineering principles to counter his/her assertions.
But then, those who hide behind pseudonyms are bound to have to work harder to be taken seriously than those who post in their own names.
I am still laughing at the idea of putting a propeller under the aircraft to help it stay airborne
Almost as ridiculous as hanging the whole machine from a large propellor and leaving the wings off.
I was not going to get involved in this long and largely impossible thread, so I shall just say that if the OP really believes that propellor thrust does not vary with speed that is his/her own problem and we may as well give up trying to use engineering principles to counter his/her assertions.
But then, those who hide behind pseudonyms are bound to have to work harder to be taken seriously than those who post in their own names.