Monday, April 19, 2021

The Wrong Wright Story Part I

The Wrong Wright Story

Part I: The Wright Brothers by Fred Kelly

A Critique by Joe Bullmer


 

This article, the first in a five-part series, addresses some of the discrepancies in Kelly’s 1943 book The Wright Brothers, (paperback reprint ISBN 0-486-26056-9) as compared to the Wrights’ original records and other well-established aviation history and scientific facts. Only his chapters IV through VIII are addressed since this material covers the period from 1899 through 1905 wherein the Wrights developed a powered controlled airplane (as discussed in chapters III and IV of my book, The WRight Story.)

On page 47 of the paperback edition of Kelly’s book, Orville gave him the impression that previous aviation experimenters such as Clément Ader, Hiram Maxim, Otto Lilienthal, Octave Chanute’s team and the Scottish experimenter Percy Pilcher had all accomplished very little. Actually, according to the French Aeronautical Society, Ader flew his first powered airplane smoothly for 165 feet (the length of his testing field) in 1890. Maxim’s powered vehicle, a result of his technical research, lifted off of its support rails for about 10 seconds and 400 feet in 1894. Lilienthal did over 2,000 controlled glides, some 1,000 feet long, during the mid-1890s, and Pilcher accomplished nearly 1,000 glides during the late 1890s.



From left to right: Clément Ader, Hiram Maxim, Octave Chanute, Otto Lilienthal, and Percy Pilcher.

In an 1895 letter, Pilcher warned of too much stability making a glider difficult to handle, something the Wrights are sometimes credited with discovering seven years later. In fact, Pilcher was creating an engine for powered flight in 1899 when he was killed attempting a gliding demonstration in foul weather to generate funds for his experiments. Lilienthal was also investigating power sources and more refined controls during the last couple years before he was killed.

By 1896, Octave Chanute’s group had accomplished around 1,500 glides. A member of his team of researchers, Augustus Herring, created a manned trussed biplane glider with smoothly cambered wings that was their most successful design. Its wing layout and structure were copied by the Wrights for their vehicles. In fact, in a letter written on December 21st, 1909, Wilbur wrote, “We have repeatedly acknowledged our indebtedness to the Chanute double-decker for our ideas regarding the best way of obtaining the strongest and lightest sustaining surfaces.” On November 30th, 1910, he penned, “we considered Chanute’s double-deck truss superior….and succeeded in adapting it to our own ideals and principles of control."  Human mo failed to use Herring’s wing shapes, which set them back a couple years until their wind tunnel showed them that they had to adopt wing camber curvatures and aspect ratios (wing length to width) similar to those used on the Chanute/Herring and Lilienthal gliders.

But even more unfortunate for the Wrights, they failed to adopt the aft surfaces that the Chanute/Herring vehicle used for control of pitch and yaw. The need for such controls had been illustrated by Sir George Cayley in a 1799 engraving, and documented in his November 1809 article "On Aerial Navigation" in Nicholson’s Journal of Natural Philosophy, Chemistry, and the Arts. In it, he stated that an aircraft needed an “up-and-down” rudder in addition to a “side-to-side” rudder, both located behind the main lifting wings. This had also been recognized by aviation experimenters since Cayley, including Jean-Marie LeBris in the 1850s, Alphonse Penaud in the 1870s, and of course Herring and Langley in the 1890s. Many of these experiments were discussed and illustrated in Chanute’s 1894 book Progress in Flying Machines, which the Wrights obtained in 1899 prior to their experiments. Ignoring or overlooking these features caused the Wrights great difficulty in developing their aircraft and, by the time they discarded the forward elevator in 1910, they were hopelessly behind other aircraft designers.

Sir George Cayley and his 1799 engraved silver disc, the first drawing of an airplane.

Evidently, not having researched aviation developments prior to the Wrights, Kelly was not aware of any of this. But even more egregious, subsequent historians and authors either did not bother to research flight experiments that preceded the Wrights, or they chose not to tarnish the Wright image established by Kelly a half century earlier. Thus evolved the myth of Wright “genius” in developing the configuration of their aircraft. In fact, aircraft layouts rapidly evolved to more closely resemble mid-19th century configurations of Cayley and LeBris than the early 20th century Wright Flyers. In any case, the impression Orville gave Kelly that previous experimenters had accomplished next to nothing is patently false.

Before leaving Herring, it should be mentioned that in 1898 he created an airplane that he claimed made a short powered flight into a stiff headwind in October of that year. Unfortunately it was destroyed in a storage shed fire before it could demonstrate its full potential.

On page 49, Orville claims that no one before them had thought of warping or bending wing extremities for lateral control. Actually, warping had been employed by LeBris in 1857, Richard Hart in 1870, John Montgomery during the 1880s, Clément Ader in 1890, Pierre Mouillard in 1896, and even Lilienthal in 1896. In fact, LeBris, Ader, and Mouillard had patented it. These controls could either yaw or roll a vehicle depending upon their degree of deflection. Slight deflections would tend to roll a vehicle away from the downward warped wing, while large deflections would yaw and roll the machine into the downward warped wing due to its disproportionately large drag increase slowing it down, actually reducing its lift. This control reversal perplexed the Wrights for a couple years until they came up with the moveable rudder to resist the yaw and force the vehicle to hold its heading while the wing warping returned it to level flight. 

 

Patent drawings by (l to r) LeBris, Ader, and Mouillard.

So the Wrights created their aft rudder not to yaw or turn, but to continue flying straight when correcting inadvertent rolls. In spite of their having explained this many times, even in their patent (see page four, lines 16 to 45), everyone who discusses the Wrights and their work always assumes their coordinated rudder was created to turn. Perhaps their lawyer, Harry Toulmin, described it most clearly in an explanation to the patent examiner, William Townsend, for their patent application based on the 1902 glider. Toulmin wrote “….the vertical rudder is in no sense a steering device, but is simply for correcting the increased resistance offered by one end [side] of the machine over the other arising from the different angles at which the ends of the planes [wings] are presented to the wind, and this it does automatically.” In fact, the Wrights’ records show that they couldn’t reliably accomplish turns with their aircraft until they disconnected their rudder from warping in 1905.

On page 53, Orville takes credit for devising the canard or forward-mounted elevator configuration of their early vehicles. In reality, Wilbur was the major designer of their early gliders. In a 13 May, 1900 letter to Octave Chanute, Wilbur stated that the 1900 glider would have an aft elevator similar to the kite they had tested the year before. But Wilbur changed his mind, and since he fabricated the machine at Kitty Hawk before Orville even arrived, it is clear Orville had little, if anything, to do with its configuration. The Wrights came to value the ability of the canard elevator to prevent stalls and avoid post-stall dives. Actually, considering the pitch instability their forward-mounted elevators created until they were abandoned in 1910, it seems odd that Orville would want to claim credit for that feature.

 


On Kelly’s page 54, Orville claims that Wilbur was the one responsible for misunderstanding the movement of a cambered wing’s center of lift with varying angle of attack, resulting in their aircraft’s instability in pitch.

On that same page, Orville makes the false statement that a positively loaded canard (one generating an up force at normal flight angles) results in pitch stability, a mistake often repeated to this day. The argument usually cited is that when an aircraft with a positively loaded canard surface is pitched up, the canard’s greater angle of attack will tend to stall it before the main wing does, thus allowing the angle of attack to drop avoiding stall of the main wings. While generally true, that is not what stability is about. Stability is concerned with how well an airplane avoids such unintentional pitch excursions to begin with. With a higher angle of attack, a positively loaded canard pulls a slightly pitched up aircraft farther up and away from a stable level attitude and toward a stall. That is unstable.

Discussing their test site on the next page, no credit is given to Chanute for recommending the Carolina and Georgia coasts, with their sand dunes and winds, as being excellent for gliding experiments. He did so in a letter to Wilbur on May 17th, 1900 while they were looking for a site.

Orville’s limited understanding, or perhaps recall, of technical issues is revealed in his discussion of the 1900 and 1901 vehicles’s glide performance on page 69. He blames the poor performance on improper maximum wing camber when in fact the poor performance was not due to the amount of maximum camber but rather to locating the maximum camber just aft of the wing’s leading edge with the rest of the wing flat or reflexed, and also to the low aspect ratio of the short stubby wings. Actually, maximum camber should occur from a third to halfway back in the wing, and aspect ratio should be at least twice what it was on those machines. Of course, Kelly could judge none of this.

 

The 1900 Wright Glider, designed primarily by Wilbur Wright.

Page 71 discusses the Wrights’ discovery of the true movements of their wings’ centers of pressure or lift without any mention of the fact that the visitors Chanute brought to Kitty Hawk, Dr. George Spratt and Edward Huffaker, had to inform the Wrights about it and suggest a test to prove it. The Wrights had thought that, just as on a flat plate, a cambered wing’s center of lift or pressure would gradually move from the leading edge to the midpoint as the angle of attack increased from zero to 90 degrees. However, on a cambered wing, at the low angles of attack used in flight, the center of lift actually moves forward as the angle increases. This is due to the more angled curvature accelerating and thinning the flow sooner along the forward upper surface of the wing. Also, any flow separation area on the aft upper surface expands forward from the trailing edge of the wing as the angle of attack increases, destroying lift there. 

Photo from Octave Chanute's 1901 visit to Kitty Hawk. (l to r: Octave Chanute, Orville Wright, Edward Huffaker, Wilbur Wright.)

Finally, during testing at Kitty Hawk in 1901, Spratt and Huffaker talked the Wrights into separating one wing from their glider and determining where it would balance in pitch at various angles of attack. This is another thing Orville had to admit under oath in his 1920 legal deposition for the Montgomery patent infringement case. He testified that “Dr. Spratt and Mr. Huffaker both suggested that there might be a rearward travel of the center of pressure on the curved surfaces at the small angles of incidence [as the angle is reduced]”. But before that, in his September 18, 1901 speech to the Western Society of Engineers, Wilbur said that “While the machine was building, Messrs. Huffaker and Spratt had suggested we would find this reversal of the center of pressure”.

Kelly recounts on page 73 that, according to Orville, in this same 1901 speech, Wilbur blamed their gliders’ poor performance on errors in the Lilienthal pressure table they had used to design the vehicles. Orville added that at the time he was not so sure that Lilienthal’s data was in error. Actually, while Wilbur only expressed uncertainty about Lilienthal’s data in that speech, I found no contemporary record of any dissension or position on the matter by Orville.

 

Otto Lilienthal's Table of Normal & Tangential Pressures

Apparently, Orville didn’t tell Kelly that a couple months later their wind tunnel actually showed there weren’t any errors in Lilienthal’s data. In fact, the errors resulted from the Wrights' poor camber shapes and aspect ratios. Wilbur clearly admitted this in letters to Octave Chanute on November 24th, 1902, stating that “[Lilienthal’s data] table is probably as near correct as it is possible”, and another on December 1st, 1902, “It is very evident….that a table based on one aspect [ratio] and [wing section] profile is worthless for a surface of different aspect and curvature. This no doubt explains why we have had so much trouble figuring all our machines from Lilienthal’s table.”

On the following two pages, Orville claims to have designed and built their first and second wind tunnels himself, and to have designed the balances in the tunnels that yielded lift and drag data. In twelve years I have found no record to support this. What I have found is a letter Wilbur sent to Chanute on October 16th, 1901 mentioning the wind tunnel photos Chanute showed them at Kitty Hawk, stating “The wind from the fan is rendered uniform in direction by the same means [as] in the photographs you showed us at Kitty Hawk”. Orville finally explained under oath in his 1920 deposition that they had gotten the design of the lift vs drag force balance from Dr. Spratt, writing, “This utilized an idea which had been suggested by Dr. Spratt.” Clearly, their guests at Kitty Hawk had familiarized the Wrights with the designs of some of the ten wind tunnels that had been built previously.

Then, on page 76, Orville claims that with their tunnel, they “discovered” the significance of wing aspect ratio - the ratio of a wing’s width or chord to its length or span. They may have, but this had already been discovered a century earlier by Sir George Cayley as documented in his November, 1809 article in Nicolson’s Journal, and by numerous experimenters throughout the 19th century such as Maxim, Lilienthal, and Langley. 

 

Sir George Cayley's glider, successfully flown with his coachman aboard in 1853.

Orville claims on the next page that “they were the first men in all the world” to compile wing design data with their tunnel that could be used to design an airplane. They were not the first. Other aviators had already compiled design data from their wind tunnels (Maxim, Zahm, Phillips, and Wenham), or by using whirling arm devices and natural winds (Lilienthal and Langley). In addition, Orville’s statement is misleading since, unlike many of their predecessors, the Wrights never published their data so it could be used for designing by anyone else.

On page 80, it’s claimed that the Wrights were the very first to know correct wing shapes by 1902. An incomplete list of experimenters that preceded the Wrights, and used camber and aspect ratio wing shapes far superior to those of the Wrights' 1900 and 1901 machines, includes George Cayley (1799), LeBris (1857), Wenham (1866), Penaud (1870), Goupil (1883), Phillips (1884), Montgomery (1885), Lilienthal (1889), Ader (1890), Langley (1890), Pilcher (1896), Herring (1896), and Whitehead (1901). All but a couple listed here actually created models or vehicles that flew. Most of this was covered in Chanute’s book, which the Wrights obtained in 1899.

l to r: Montgomery's 2nd Monoplane Glider; Langley's Aerodrome No. 5; Whitehead and his No. 21 aircraft

On page 81, Orville takes complete credit for figuring out the problem caused by the fixed vertical tails on the 1902 glider, and figuring out the solution of a moveable rudder. But Kelly takes the discussion too far by claiming that the Wrights’ system of ailerons (actually warping) and rudder deflection is used today (today = 1943?). Furthermore, the following paragraph explains that the Wrights connected them to move together automatically, a system since used briefly in only a very few aircraft and discontinued due to safety concerns. Even the Wrights found that the controls had to be disconnected and used at different times and with different deflections. For example, when correcting a roll, less rudder deflection is required to hold a heading than is used to swing the airplane into a coordinated turn. In fact, on an airplane with dihedral, the controls for roll and yaw are cross-controlled (i.e., one is reversed) to side slip in a crosswind landing. 

 

The flight crew for the 1902 Wright glider, from left to right: Octave Chanute, Orville Wright, Wilbur Wright, George Spratt, Augustus Herring, and Dan Tate.

 

Orville says on page 84 that they doubted that an engine of 20 pounds per horsepower was available, but Wilbur wrote his father on September 23rd, 1900 claiming that they would have no problem obtaining a suitable engine. Actually, engines of half that weight per horsepower existed at that time. It seems likely that the Wrights had their assistant Charlie Taylor build their engines simply because they didn’t want to spend the money for existing ones, particularly since they thought there was a good chance of destroying at least one of them in testing.

On page 89, Orville claims that they developed a better understanding of the proper design of a propeller than anyone else, but does not claim that they were the first to see the propeller as a spinning wing. The latter has been incorrectly implied or assumed, without research, by almost all historians and authors since Kelly. As reported in a previous article in this blog, in 1885 Sidney Hollands presented a paper to the Aeronautical Society of Great Britain explaining that a propeller should be cambered, twisted, and tapered toward the tips. This was reported in Chanute’s book, which, again, the Wrights had obtained in 1899. (Reverse taper, as used by the Wrights, puts unnecessary bending and twisting loads on the blades and exaggerates aerodynamic losses at the tips, much as reverse taper on wings would require heavier structure and degrade their efficiency.)

 

Page 101 presents the Wrights’ famous claim that on their fourth trial on December 17th, 1903 their aircraft flew 852 feet in 59 seconds, a feat not verified by any witnesses or by photography. At least four different analyses have determined that the photo claimed by Orville to portray the end of the fourth flight shows the vehicle to be stopped less than 280 feet from the launch rail. For a detailed mathematical analysis of the photo see the November, 2019 article on this site.

Kelly, on page 128, appears to give total credit to the Wrights for the idea and design of the falling weight catapult first used in 1904, as have authors and historians since. In actuality, the idea and design were given to them in a July 29th, 1902 letter from Chanute, who himself got the design from Albert Merrill, a New England gliding enthusiast. Chanute wrote “I have your letter of July 27th and enclose a letter from Merrill and some photos”, and farther along, “Merrill had written to me to get my endorsement for…..a method for imparting initial velocity for a glider through a falling weight”.

Page 133 contains an interesting claim by Orville that, although they had to disconnect the rudder from wing warping in 1905 in order to make turns, they reconnected it “several years later”, albeit with a device to alter rudder deflection to enable both roll corrections and turns. I have never found any contemporary record of this, but if true, it must have been temporary and prompted by some opponent in a patent suit pointing out that testing forced them to abandon the very control scheme they patented and were defending in court. The technical limitations of a warp/rudder interconnect were explained in previous comments about Kelly’s page 81.

These are the major discrepancies in Chapters IV through VIII of Kelly’s 19-chapter book. They contradict information in Wright letters and records made from 1899 through 1905, the years from the Wrights first experiments through to the development of a controllable airplane. Many of these differences could be said to have been fabricated, or at least exaggerated, by Orville to glorify his contribution. Others might ascribe them to forty years of fading memory. However, many other details were accurately recounted, and there are other examples of Orville, after Wilbur’s passing, having claimed credit for things that are not supported by their contemporary records.

It is evident that using Kelly’s book as a basis, a narrative of the Wrights’ development of the airplane could end up quite different from that derived from the far larger mass of contemporary records along with such material as Orville’s 1908 article in The Century and his 1920 legal deposition. This would be particularly true if someone only vaguely familiar with the science were to fill in numerous blanks with assumptions. Unfortunately, that’s what has happened over the intervening three quarters of a century. This will become obvious in subsequent articles here discussing other books and the latest TV documentary

In all fairness to Kelly, it should be pointed out that his book was published ten years before McFarland’s compilation of the actual Wright records. Without McFarland’s compilation, it would have taken years for Kelly to have fact checked Orville’s statements. And that’s if he had reason to suspect that Orville was sometimes spinning yarns. But the other books and program I will be reviewing do not have that excuse. These, and countless other books and documentaries, were created a half to two thirds of a century later and appear to be products of either poor research, technical inadequacy, or a desire to glorify the Wrights’ legacy.  

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 "The Wright Brothers A Biography by Fred C. Kelly, 1989, Dover Publications, Inc. 31 East 2nd Street Mineola, N.Y.11503

(First published by Harcourt, Brace and Company, New York, 1943 as The Wright Brothers: A Biography Authorized by Orville Wright)