The thing was "control" was obviously 'easy' once it had been done but everyone had been looking in the wrong direction. Once pointed out...
Randy
Could the invention of heavier than flight be delayed?
- Thread starter GlebPro2004
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The thing was "control" was obviously 'easy' once it had been done but everyone had been looking in the wrong direction. Once pointed out...
Randy
I'm amazed that manned heavier than air flight took as long as it did to take place. The principles of stability were demonstrated by Penoud's Planophore in 1871, which lacked only wing dihedral angle to match the ability to maintain stable flight of the "free-flight" models of the 1920s. The requirement for developing differential lift which is held as required for manned flight, is unnecessary in an inherently stable (like an uncontrolled model) aircraft. Sufficient rudder and elevator authority for controlled flight has its precedent in boat rudders, tho there would be some adverse yaw in turning without ailerons, wing warping or-my favorite- spoilers. The "pilot" would be more like a yacht helmsman than a unicycle rider.
I believe that the propulsion problem was the gating issue. It appears that just about every attempt incorporated an engine(s) that could run for hours, rather than a lightweight device capable of a few minutes run. Clement Ader's 1890 hop was powered by a steam system which incorporated a heavy and drag producing condenser above the wing. Percy Pilcher and the Wrights used water cooled engines, etc. I would have investigated existing torpedo motors which were marvels of lightweight power for the time and ran 3 or 4 minutes. Alternatively a flash steam generator and all-loss system might attain 4 or 5 pounds per horsepower. After demonstrating controlled flight was time enough to go for endurance. Building on Penaud's configuration, manned flight could have been accomplished by 1890-latest.
Wish I could have been there.-- Dynasoar
I believe that the propulsion problem was the gating issue. It appears that just about every attempt incorporated an engine(s) that could run for hours, rather than a lightweight device capable of a few minutes run. Clement Ader's 1890 hop was powered by a steam system which incorporated a heavy and drag producing condenser above the wing. Percy Pilcher and the Wrights used water cooled engines, etc. I would have investigated existing torpedo motors which were marvels of lightweight power for the time and ran 3 or 4 minutes. Alternatively a flash steam generator and all-loss system might attain 4 or 5 pounds per horsepower. After demonstrating controlled flight was time enough to go for endurance. Building on Penaud's configuration, manned flight could have been accomplished by 1890-latest.
Wish I could have been there.-- Dynasoar
Picking up on my last post (with apologies for misspelling Alphonse Penaud's name earlier)-
In my opinion one of the Wright brother's contributions, copied by virtually all early air adventurers, held back the development of truly practical aircraft till at least 1918. The problem was their marvelous wind tunnel. In this device they were able to measure the lift and drag characteristics of many airfoils (wing cross sections). These measurements involved 4 to 6-inch chord test sections at a wind speed of about 40 MPH. Their results indicated that a thin curved airfoil, much like the cross section of a bird's wing provided the best lift/drag ratio. The early aircraft had to extensively brace the virtually sparless wings with tension wires. This continued until late 1917 when both Hugo Junkers and Fokker Aircraft's chief designer Reinhold Platz independently decided to try substantially thicker airfoils to enclose much deeper spars; Junkers in cantilever wing all metal aircraft and Platz to eliminate wire bracing for a new biplane fighter. Platz, in particular hoped that the elimination of the wires would compensate for the unusual thick wing. The thick wings were spectacularly successful and paved the way toward much better aircraft performance in the future.
In hindsight it was clear that the birdlike airfoils that emerged from the Wright bros. wind tunnel and dominated early aviation, were ideal for 6-inch wide wings flying at 40 MPH-just like birds and that airflow characteristics at 100 MPH with 6-foot wing chords were quite different. The parameter Reynolds Number, which considers the viscosity and inertial forces in fluid flow, in the Wrights' wind tunnel was dramatically smaller than encountered by real world airfoils.
Dynasoar.
l
In my opinion one of the Wright brother's contributions, copied by virtually all early air adventurers, held back the development of truly practical aircraft till at least 1918. The problem was their marvelous wind tunnel. In this device they were able to measure the lift and drag characteristics of many airfoils (wing cross sections). These measurements involved 4 to 6-inch chord test sections at a wind speed of about 40 MPH. Their results indicated that a thin curved airfoil, much like the cross section of a bird's wing provided the best lift/drag ratio. The early aircraft had to extensively brace the virtually sparless wings with tension wires. This continued until late 1917 when both Hugo Junkers and Fokker Aircraft's chief designer Reinhold Platz independently decided to try substantially thicker airfoils to enclose much deeper spars; Junkers in cantilever wing all metal aircraft and Platz to eliminate wire bracing for a new biplane fighter. Platz, in particular hoped that the elimination of the wires would compensate for the unusual thick wing. The thick wings were spectacularly successful and paved the way toward much better aircraft performance in the future.
In hindsight it was clear that the birdlike airfoils that emerged from the Wright bros. wind tunnel and dominated early aviation, were ideal for 6-inch wide wings flying at 40 MPH-just like birds and that airflow characteristics at 100 MPH with 6-foot wing chords were quite different. The parameter Reynolds Number, which considers the viscosity and inertial forces in fluid flow, in the Wrights' wind tunnel was dramatically smaller than encountered by real world airfoils.
Dynasoar.
l
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Hugo Junkers started building a wind tunnel in 1910, and produced the steel cantilever monoplane J-1 in 1915, subsequently witnessed and copied by Anthony Fokker through Reinhold Platz. Much of the art of aircraft design in the era was who you copied, along with some brilliant originality. Junkers kept much of his ideas unpublished for patent reasons. Boeing used a Junkers patent process in B-17 wing construction.
How early and disruptive of a PoD is allowed? Because short of generally retarding technology by 30 years I don't really see a way for this to happen.
Leo,
A few comments on Prof Junkers cantilever monoplanes- If you look a a picture of the steel J1 and compare it with his later aluminum monoplanes, the airfoil thickness has been substantially increased, to provide the nearly geometric increase in stiffness of a uniformly loaded cantilever beam. The J1 wing was constructed of high silicon electrical iron, as used in for laminations in electric motor stators. As shown in photos, this wing thinned substantially toward the tips due (probably) to the ability of the bottom flat steel wing skin not to deform under tension. Junkers later wing design utilized chordwise corrugated soft aluminum wing skins which would elongate freely in tension perpendicular to the corrugations. Consequently wing structural depth had to be increased to regain the stiffness lost. While I recognize that the Junkers wing employed a truss structure in place of spars, the disproportionate increase in stiffness that accompanies increase in section depth still applies. The increase in wing thickness of Junkers and Fokker were close to contemporary, but for different structural reasons.
I'm not familiar with Junker's wind tunnel. Did he consider Reynolds Number correction? At that time only Ludvig Prandtl seemed aware of its effect.
Dynasoar
A few comments on Prof Junkers cantilever monoplanes- If you look a a picture of the steel J1 and compare it with his later aluminum monoplanes, the airfoil thickness has been substantially increased, to provide the nearly geometric increase in stiffness of a uniformly loaded cantilever beam. The J1 wing was constructed of high silicon electrical iron, as used in for laminations in electric motor stators. As shown in photos, this wing thinned substantially toward the tips due (probably) to the ability of the bottom flat steel wing skin not to deform under tension. Junkers later wing design utilized chordwise corrugated soft aluminum wing skins which would elongate freely in tension perpendicular to the corrugations. Consequently wing structural depth had to be increased to regain the stiffness lost. While I recognize that the Junkers wing employed a truss structure in place of spars, the disproportionate increase in stiffness that accompanies increase in section depth still applies. The increase in wing thickness of Junkers and Fokker were close to contemporary, but for different structural reasons.
I'm not familiar with Junker's wind tunnel. Did he consider Reynolds Number correction? At that time only Ludvig Prandtl seemed aware of its effect.
Dynasoar
Kaze
Banned
The best route would actually be killing the Montgolfier Brothers before the first hot-air balloon fight. The flight of the hot air balloon does have some bearing on heavier than air flight - basically, it spurred inventors to their work to make something more maneuverable than what the Montgolfier brothers invented.
I don't know of any mention of Reynolds number correction, but he did rub shoulders with Theodore von Karman who also taught at TH Aachen, and inspected the wind tunnels of Eiffel and Gottingen, and consulted with others. In addition, he built a tunnel of 26.9 square feet at Dessau capable of 111 mph, and a further closed loop tunnel. I'm of the opinion that he paid due diligence to both turbulence and Reynolds number.
Von Karman called him a great teacher, industrialist and scientist. And he didn't like nazis. An all-around great guy.
along with Santos Dumont 'This one should work better' No.14
Having Santos Dumont make the first flight could actually speed up development since he refused to patent and made everything freely available.