Sunday, February 20, 2022

The Wrong Wright Story Series: Wings


The Wrong Wright Story 3

Tom Crouch's Wings: A History of Aviation from Kites to the Space Age

a critique by Joe Bullmer

This is the third article in a five-part series presenting critiques of four of the most popular books and the most prominent TV documentary produced concerning the Wright brothers’ development of a manned, powered, controllable airplane.  Previous reviews discussed Fred Kelly’s 1943 book The Wright Brothers, A Biography, and Peter Jakab’s 1990 book Visions of a Flying Machine. 

 


This article discusses Tom Crouch’s book Wings: A History of Aviation from Kites to the Space Age published in 2003 by the Smithsonian, ISBN 0-393-32620-9.  This 725-page book undertakes the monumental task of covering all airplane development from da Vinci to the 21st century.  In this review, a couple of the book’s comments on 19th century developments are addressed, along with its description of the Wrights’ work leading to the final version of their Flyer III aircraft in October of 1905. 

These critiques are being done by an aircraft design and performance engineer and author of The WRight Story, The True Story of the Wright Brothers’ Contribution to Early Aviation. That book contradicts much of the content of the books and videos reviewed in this series.  The author of these reviews has also published four reviews of technical papers presented in The Wright Flyer-An Engineering Perspective, and two articles concerning the Wrights’ testing at Kitty Hawk, all of which have appeared at this site over the past couple years.

Some explanations appearing in previous articles are repeated in this one. A number of the same mistakes are made in this book, and each of these articles is intended to stand on its own. Forbearance is appreciated. Technically competent comments on these articles, or The WRight Story, are welcomed.

Chapter 1 

Page 33:  The author, without citing a reference, claims here that Sir George Cayley, in his 1809 article in Nicholson’s Journal of Natural Philisophy, Chemistry, and the Arts, identified an area of low pressure on the upper surface of a cambered wing.  Actually, Cayley mentioned “a slight vacuity immediately behind the point of separation ….under the anterior [forward] edge of the surface.”  He envisioned this air trapped under a thin cambered wing moving back under the wing and eventually being forced downward by the aft portion of the cambered wing, thus imparting the upward force on the wing.

 

Sir George Cayley, aviation pioneer

 

On the same page, Crouch claims “Cayley had a lifelong preference for oars as propulsion.”  Actually, in spite of an early drawing showing oars, Cayley was well aware of the futility of such a scheme.  Over most of the second, third, and fourth decades of the 19th century, along with activities unrelated to aviation such as serving in Parliament, Cayley searched for a lightweight mechanical source of rotary power.  Unfortunately, by the middle of the 19th century studies of contained explosions of petro-chemicals were just beginning, so Cayley gave up his search for mechanical power and returned to gliders.

Page 36:  Orville Wright is quoted as saying “Henson, Stringfellow, and Marriott made no contributions to the art or science of aviation worth mentioning.”  But then Orville went on, “Every feature of Henson’s machine had been used or proposed previously.  His mere assemblage of old elements certainly did not constitute invention.”  I find it curious these statements were included in this otherwise complimentary book.  Except for their chain drive of propellers and interconnected rudder and warping, which soon had to be abandoned, Orville’s statement applies exactly to what he and his brother did.  In this one statement Orville’s judgement actually disqualifies himself and his brother as inventors.

 

William Henson and his Aerial Steam Carriage

Page 43:  Here Hiram Maxim’s huge 1893 flying machine is described as having a 180 hp steam engine driving one 18-foot propeller.  In fact, numerous photos show that it had two such engines driving two 18-foot propellers.  This is important since the engines were to be independently throttled to yaw the vehicle which, in conjunction with dihedral on the outer wings, was intended to enable turning.  The vehicle was never flown freely and this scheme was never validated.  It also was the only prominent vehicle prior to the Wrights to feature an adjustable horizontal forward surface or canard (which was also never used).

 

Chapter 2

Page 65:  The author credits the Wrights with the “genius” that was “never more apparent” than in devising their wind tunnel balance that, through a mysterious “cascading chain of forces”, could indicate the relative magnitudes of the lift and drag forces on a miniature test section of a wing.  In fact, the device, indicating lift versus drag, was simply a flexible parallelogram that was explained to them by Dr. George Spratt during his visit to their Kitty Hawk test site during the summer of 1901.  Wilbur admitted this in an October 16th, 1909 letter to Dr. Spratt, and Orville admitted it in his sworn deposition for the 1920 Montgomery case.

George Spratt's visit to Kitty Hawk, 1901

Wind blowing on the test wing would allow it to pull the parallelogram to an angle, the trigonometric tangent of which would yield the wing’s lift-to-drag ratio.  The Wrights modified this design to show the force on a test item versus the drag on flat plates perpendicular to the air flow.  It appears the whole idea of a wind tunnel was raised by Octave Chanute, Dr. Spratt, and Mr. Huffaker at Kitty Hawk during their visit in 1901.  There is no record of Orville or Wilbur even mentioning one before discussing it with Chanute and his cohorts that summer.  Chanute also showed them detailed photos of wind tunnel components during that visit.

On this same page the author claims the Wrights “discovered” the proper wing camber and aspect ratio with their wind tunnel.  What they discovered was that they had to abandon the totally inappropriate wing shapes they had been using for two years in an attempt to suppress the instability caused by their canard. Instead, to get sufficient lift they had to revert to the wing shapes that had been used previously by Lilienthal and many others.  They also admitted this in a November 24th, 1901 letter to Octave Chanute.

 

The Wrights' letter to Octave Chanute

Page 66:  Here it is claimed that the original 1902 glider “sport[ed] a rudder”.  In fact, it did not.  What it had were two fixed vertical stabilizers.  Only later, when it was found that this made the spin problems worse, was it changed to one moveable vertical rudder.  (A fixed aft surface is a stabilizer.  A moveable one is either a rudder or elevator.)  Deflection of that rudder kept the glider from spinning in when warping was used to correct an inadvertent roll.  (See The WRight Story, Chapter IV, or the discussion in the previous article concerning page 112 of the book “Visions of a Flying Machine” for more detail.)

The 1902 Wright glider.

Page 67:  It is claimed that the Wrights’ first engine developed 12 hp “after it had been running for a few minutes.”  Actually, with only convective water cooling and a poor oiling system, the first engine would overheat within little more than two minutes of running.

Page 70:  The ludicrous statement attributed to Orville Wright by the Dayton Journal in 1923 is presented, claiming that the 1903 “Flyer” could have flown for 20 minutes at 1,000 feet of altitude.  Not only would the engine have overheated and seized in little more than a couple minutes, but the vehicle only had enough power to climb about half way out of ground effect, i.e., only about 15 feet above the ground.  And this vehicle could not be effectively controlled!  It’s disturbing that the National Air and Space Museum’s Curator for Aeronautics would write a book without being aware of any of this.

Page 81:  The device that allowed the Wrights to accomplish a successful test program at Huffman Prairie in 1904 and 1905, their catapult, is mentioned, again without any credit whatsoever being given to Octave Chanute for introducing the concept and basic design to the Wrights.  This suppression, or ignorance, of Chanute’s contributions to the Wright’s efforts (as listed in the discussion in the previous article in this series regarding page 84 of the Jakab book) is universal with Wright authors, as is lack of recognition of Chanute’s and Spratt’s contributions to their wind tunnel.  These, and other such omissions, are used to build the myth of the Wrights’ legendary “genius” enabling them to see the solution to every problem they encountered completely on their own.

 

Further along on page 81, disconnecting the rudder from the warping control to enable maneuvers is mentioned.  Their 1903 aircraft couldn’t lift itself off of the ground on its own, couldn’t climb even half way out of ground effect, damaged itself in half of its landings, was totally unstable, couldn’t be controlled or turned, and had an engine that couldn’t run more than two minutes.  But by October of 1905 they had developed an airplane that could be catapulted into the air with no headwind, could climb out of ground effect with an engine that could run over a half hour until fuel depletion, was much less unstable and could be kept under control, could be turned at will, and could be landed without damage.  In this book this is all attributed to “growing experience in the air”.  Nothing is mentioned of having had to lengthen and strengthen the airframe, completely change the balance of the machine, changing wing anhedral to dihedral, changing size, location, loading, and pivoting of the canard, devising aerodynamic turning aids, also creating cooling, an oiling system, and the fuel feed and mixing systems of the engine, and going through numerous propeller designs.  To say nothing of numerous crashes, busting up airframes, wings, propellers, even engines, along with a few minor injuries to themselves. 

Left: Wilbur with the 1903 Wright Flyer; Right: the 1905 Wright Flyer III

I understand a book that purports to cover the entire evolution of flight up to the present day must take occasional shortcuts.  But two years of testing, modification, and results were just summarized here in one paragraph.

Page 124:  The erroneous and demeaning assertion is made that the Wrights “were far less interested in scientific theory or the fundamental physical principals underlying flight”.  The author of Visions made the same assertion in person, putting it more strongly by saying that “They were engineers, not scientists”.  Obviously, these history majors don’t appreciate what it takes to do competent professional aircraft design engineering.

The Wrights thought they understood the physical principles involved.  That is what distinguished them from most of their predecessors.  Unfortunately, in some cases they were wrong, including the physics principal most basic to their airplane: how a cambered wing generates lift.  This is verified by a number of their writings, including their major patent, giving erroneous explanations of lift.  And they paid dearly for that mistake, largely wasting their first two years of development work and testing, and adopting a configuration that soon put them behind their competition.

 

The Wright's 1908 patent designs

In the next two paragraphs the author goes even further into unfamiliar territory, claiming that engineers don’t agree on how a horizontal spinning cylinder generates lift.  He then goes on to settle this dispute for them by giving an explanation without mentioning boundary layers or stagnation points, key elements to understanding the phenomenon.  Perhaps the “engineers” advising him should go back to their first semester aerodynamic texts - if indeed any of them ever did study aerodynamics.

Pages 134 & 135:  The expenditures by various countries on aviation up to WWI are listed showing the United States ranked fourteenth behind such countries as Chile and Bulgaria.  But no mention is made of this largely being due to the Wrights stifling the development of aviation in the U.S. with their various patent suits and legal actions.  Much of this was enabled by judgements from the notoriously inept and corrupt New York District Judge John R. Hazel.  They were demanding 10 percent royalties from any airplane related incomes, including exhibitions, and 20 percent from their only real competitor, the Curtiss company.  Not only did the Wrights suppress aircraft production and development in the U.S., but even basic aviation research in academia was largely eliminated because of the resulting lack of industry interest or funding for such research.

 

Judge John R. Hazel
 

How ironic that the very guys that, up through 1908, had put the U.S. first in the world in aircraft development, managed in the next five years to drag the U.S. down to a handful of uncompetitive unserviceable military airplanes while the major European nations each had hundreds of modern capable combat aircraft.  In fact, the original Wright Company only lasted five years, and the second, the Dayton Wright Company, only survived WWI by building a faulty British design under license.

Page 147:  For some unstated reason the Wrights’ commercial failure is primarily attributed by this author to their pusher propeller designs having the propellers located behind the wings.  This is odd since the success of everything from the Republic Seabee to the Convair B-36, the U.S.’s first true intercontinental bomber, would indicate otherwise.  Hundreds of B-36’s were produced, constituting, along with B-47’s, the U.S. strategic nuclear deterrent from the late 1940’s through the 1950’s.  Obviously its six huge pusher propellers were no impediment to its success.

 

Republic Seavee and Convair B-36

No mention is made of early Wright aircraft’s lack of wheels complicating ground handling and requiring a rail and large catapult for launching, canard induced stability problems, warp-induced spins, no useful load capability, and a disproportionate share of crashes and crew deaths.  These deficiencies rendered Wright airplanes essentially useless for the military, the first large American user of aircraft.  By the time the Wrights eliminated these problems the rest of the aircraft industry had left them far behind.

Summary

Wings was an ambitious undertaking, attempting to cover over two centuries of aircraft development and production in 725 pages.  Over 100 contributors are listed in the Acknowledgments.  However, again, as with Visions, the last book reviewed, only very few of these contributors were ostensibly qualified to contribute any technical assistance, and these people apparently had woefully inadequate knowledge of the Wrights.

As would be expected in a Smithsonian book of this scope, many hundreds of notes were listed at the back.  However, only one of the comments made in this summary pertains to a passage in Wings supported by any of these references, that to an article in the Dayton Journal in 1923 quoting a universally discredited statement by Orville Wright.

It appears this author relied heavily upon the advice of the author of Visions of a Flying Machine since a number of the same exaggerations and errors appear in both books.  Also familiar is the technique of replacing research with assumptions and opinions.  One would expect more on such an important subject from the highest level of the Smithsonian’s National Air and Space Museum.

Any book of this scope would, of necessity, omit much detail.  But that does not excuse the inclusion of incorrect information, particularly on what is universally considered the origin of the entire technology and industry.  This is particularly unfortunate since so many “aviation historians” have relied on this material as the basis for their work.



Sunday, September 19, 2021

The Wrong Wright Story Series: Visions of a Flying Machine II (Part 2)

The Wrong Wright Story 2

Peter Jakab's Visions of a Flying Machine

Part II of a critique by Joe Bullmer

Introduction to Part II

The previous article in truthinaviationhistory discussed the first four chapters of the book Visions of a Flying Machine by Peter Jakab. In this article, the subsequent six chapters of that book are critiqued. The article begins with a listing of the largely overlooked, but well documented and vital contributions to the Wrights' efforts made by Octave Chanute. The damage done to the historical record by Visions is summarized at the end of this article.

Left: Peter Jakab’s Visions of a Flying Machine. Right: The Wrights’ mentor, Octave Chanute.
 
 Chapter 5: "Riding the Winds"

Page 84: The Wrights’ relationship with Octave Chanute is discussed by saying that “Chanute provided the Wrights with little genuine technical assistance and few if any useful theoretical ideas.” This egregious falsehood is exactly opposite of the truth. According to records of their correspondence, Chanute provided the Wrights with, or alerted them to:

  • His 1894 book that was the basis for their study of earlier works.
  • Realizing the biggest problem remaining to be solved was control.
  • The need to master control with gliders before adding power.
  • Trussed biplane wing construction.
  • First testing gliders unmanned with tethering lines.
  • The best gliding areas are the coasts of Georgia and the Carolinas.
  • His cohorts (Huffaker and Spratt) who showed the Wrights the reversal of the center of lift’s movement.
  • Doing tests with a wind tunnel to determine better wing shapes.
  • Photos of wind tunnels and the design of their lift balance.
  • The basic design of a falling weight catapult enabling testing near Dayton and flying for the next six years.

In fact, it is evident that without these inputs the Wrights may well not have succeeded. If they did it would have taken them far longer, which may well have denied them the reputation of being the first to accomplish powered, manned flight.


 Page 110: The claim is made that the wing tests at Kitty Hawk “confirmed their earlier assumption regarding the reversal of the center of pressure [lift].” As previously discussed in relation to page 65, the Wrights did not have an “earlier assumption regarding the reversal of the center of pressure”. They admitted that the Kitty Hawk tests suggested to them by Huffaker and Spratt in 1901 showing the reversal of center of pressure movement came as a complete surprise to them.
Left: Dr. George Spratt (photo from the Harold E. Morehouse Flying Pioneers Biographies collection in the NASA archives); Right: Edward Huffaker

Page 112: Here, the author’s shoddy research has led countless subsequent authors and historians into an unintended error. A discussion on the Wrights’ problem with wing warping drag is opened by saying “Wilbur took the next step and attempted to make an intentional turn with wing warping.” In fact, the Wrights, particularly Orville in his 1920 deposition, made it perfectly clear that they were not attempting turns at Kitty Hawk, but rather were simply trying to maintain heading and avoid spins while correcting inadvertent banking when they ran into the problem.

They had put anhedral or droop into their wings to facilitate traversing a hill without getting rolled and blown sideways into it. Unfortunately anhedral made their gliders unstable in roll since the higher wing would develop more lift than the low one. But when they used warping to bring the glider back level, the downward warp on the low wing gave that wing substantially more drag causing it to drag back and slow down so much that it actually lost lift. This made the vehicle spin and roll further into the bank rather than level out.

Describing this problem in his 1920 deposition, Orville testified that “Sometimes in warping the wings to restore lateral balance…” In another reference to roll control he stated “When the wings were warped in an attempt to recover lateral balance…” On page three of their 1906 patent, it says “…owing to various conditions of wind pressure and other causes, the body of the machine is apt to become unbalanced laterally…. The provision we have just described [wing warping with coordinated rudder] enables the operator to meet this difficulty and to preserve the lateral balance of the machine.” Nowhere does their 1906 patent address turning.

The Wrights also describe their glider spinning into the lower lagging wing and auguring it into the sand. The Wrights referred to this as “well digging”. Had they been trying to turn, the vehicle would have slipped straight toward the other side, which it didn’t.

Actually, with the rudder mechanically connected to the wing warping, and only deflecting enough to keep the 1902 vehicle going straight, both it and the 1903 Flyer couldn’t turn. In fact, the Wrights were only able to make turns after they disconnected the rudder from warping in 1905. However this error in the book, along with laziness and/or lack of understanding by subsequent authors and historians, has perpetrated to this day the myth of the Wrights practicing intentional turns at Kitty Hawk.

Chapter 6: "Seeking Answers: The Wrights Build a Wind Tunnel" 

A 1949 reproduction of the Wright Wind Tunnel by the National Cash Register company

Page 119: This chapter launches into a two-chapter discussion of what was supposedly wrong with Lilienthal’s lift data to cause the Wrights to have lifting problems in 1900 and 1901. Right away it erroneously states that they used Lilienthal’s incorrect value of Smeaton’s coefficient for both of these vehicles. This is obviously wrong since wing area is proportional to Smeaton’s, and the ’01 vehicle had twice the wing area of the ’00.

This two-chapter discussion of what was “wrong” with Lilienthal’s data and how the Wrights “corrected” it with their wind tunnel, includes a whole series of falsehoods that have been repeated ad infinitum by authors and “experts” for over 30 years. The first blunder is saying that Lilienthal used Smeaton’s coefficient to calculate his lift coefficients from the equation

This is absolutely wrong since, as evident in Lilienthal’s book, Birdflight as the Basis of Aviation, he simply compared the lift on his wing sections at various angles of attack to their drag at 90 degrees. Since, at that time, the drag coefficient of any plate at 90 degrees was taken to be 1.0, the ratio of the pressures was the lift coefficient directly.

Lilienthal's glider. Photo from britannica.com

The next blunder was spending pages on what was wrong with the whirling arm device used back then by many experimenters to calculate lifting data. As its name implies, a long arm went round and round with a test section on its tip. Obviously the test section was (without a breeze) continually passing through its own wake of turbulent air which could cause errors. Lilienthal did use a 25-foot diameter whirling arm to calculate some of his data. However he also did tests in steady natural wind with no turbulence. Both of these data were plotted as “Plates” at the back of Lilienthal’s book.

Lilienthal's whirling arm device.

Later Lilienthal took the tabular data of lift coefficients for one of these plots and published it in James Means’ Aeronautical Annual. Anyone willing to go through the trouble to compare all of the table entries to the corresponding points on the plots in the back of Lilienthal’s book can see that the tabular data, which is all the Wrights had, exactly corresponds only to the points on the plot for a natural steady straight smooth wind. So, contrary to assertions in the subject book, the data the Wrights used had nothing to do with a whirling arm, or Smeaton’s coefficient.
James Means' Aeronautical Annual

Along with a lengthy discussion of the Wrights’ wind tunnel (we’ll get to that in a moment) the author spends a substantial part of the next 30 pages trying to say what could cause errors in Lilienthal’s data without actually determining anything. He uses the terms “could have”, “might”, “if”, “could be misleading”, “problems”, and “may have’s” without ever reaching a conclusion. The author’s task is made worthless by the fact that the Wrights admitted in a November 24, 1901 addition to a letter to Chanute (originally dated November 22, 1901) that the errors causing poor lift were theirs, not Lilienthal’s, and that there was nothing really wrong with Lilienthal’s data.


Page 124: Near the bottom of this page we are told that “the Wrights’ wind tunnel work best demonstrates their brilliance as engineers”. No mention is made of the fact that the idea and design of the tunnel was discussed with the Wrights by Chanute and his cohorts, Huffaker and Spratt, at Kitty Hawk. In fact, the subject was probably brought up by the Wrights’ guests since there is no mention anywhere of a tunnel by either of the brothers before then. As previously mentioned, during the summer of 1901, Chanute showed the Wrights photos of existing wind tunnels, and Spratt gave them the design of their “ingenious” and “inventive” lift balance with which to take test measurements.
 
Visitors to Kitty Hawk: l-r Octave Chanute, Orville Wright, Edward C. Huffaker, and Wilbur Wright.

In a letter to Chanute from October 16th, 1901, Wilbur refers to the photos, and in a letter to Dr. Spratt from October 16th, 1909, he discussed Spratt’s lift balance and claims he will be sure to give Spratt his due credit for the idea in the future. Orville also mentioned that the lift balance was Spratt’s idea in his sworn deposition for the 1920 Montgomery court case.

Throughout just this one chapter he lavishes gushing adjectives and phrases on the Wrights, including “imaginative, clever, conceptualizing, genius, marvels, ingenious, incredibly impressive, amazing, sophistication, inventive, visualizing, think through a problem clearly, and technical skill.” He even, on page 135, gives the Wrights credit for devising the scheme of calculating lift coefficients from force ratios and thus avoiding the use of the controversial Smeaton’s coefficient, not realizing, as was just discussed, that is exactly how Lilienthal did it ten years earlier.

Page 144: Here the erroneous claim that Lilienthal’s lift coefficients were wrong is repeated. A blunder trifecta is completed by repeating his claims that Lilienthal used a whirling arm and an incorrect Smeaton’s coefficient to generate the lift coefficients the Wrights used

Page 146: A plot of the Lilienthal lift coefficients versus angle of attack is presented along with the Wright data for a similar wing. This clearly shows that the data are basically coincident at the angles used in flight, and that Lilienthal’s data are more consistent than are the Wrights’ data. Not questioning the validity of his previous claims, the author merely attributes this data agreement to coincidence.

Pages 147 & 148: Here the author goes completely off the rails again saying that “Lilienthal’s….table had an even greater drawback” in that it could only be used for one wing shape! This statement is nothing short of bizarre. That is the purpose of lift coefficients, to express the different performances of differently shaped wings of the same size at the same flight conditions. This statement is exactly equivalent to saying that Volkswagen wheels are no good since they won’t work on a dump truck, or the recipe book has a drawback in that it calls for different temperatures or baking times for different dishes.

Page 149: While he’s out of his element, the author calls the fact that Lilienthal’s lift coefficient data can only be used for one given airfoil or wing shape a “stumbling block” and a “pitfall”. But farther down the page he magnanimously forgives Lilienthal’s “mistakes” because of all his “contributions to the advancement of aeronautics.”

Page 150: Here, after having sung their praises in previous chapters, the author finally acknowledges that the 1900 and 1901 Wright gliders had inadequate lift.

Page 152: The subject of induced drag is raised and the author ascribes the improved efficiency of the 1902 wings to an improved camber or curvature shape. Although the Wrights’ camber change probably changed lift coefficient somewhat, the vast majority of the reduction in induced drag was due to their more than doubling the aspect ratio from 1901 to 1902.

Page 153: The Wrights’ discovery of the significance of aspect ratio is mentioned here with no recognition that this was known by George Cayley a century earlier, and by many aviators in between. The Wrights could have learned this, years earlier, simply by reading. He also fails to mention that, along with changing their wing camber shape to much like that used by their more successful predecessors, they also changed their wing’s aspect ratio from 3.1 to 6.5, exactly the value used by Lilienthal on his test wings.

Sir George Cayley

Page 156: Reprinted here is Orville’s boast about how their predecessors were so ignorant of camber that they all used highly inefficient shapes and none had developed good data. Orville wrote “we possessed in 1902 more data on cambered surfaces, a hundred times over, than all of our predecessors put together.” Unfortunately this author, and apparently all others, are unaware that although the Wrights may have had more data that any others, they totally failed to understand the basic aerodynamic principal that caused their data

But their predecessors, Augustus Herring, Horatio Phillips, and Otto Lilienthal, did understand lift. They all knew that the primary cause of lift on a cambered wing was lowered pressures on its upper surface. The Wrights thought it was all due to pressure on the bottom of a wing that met the flow at a positive angle. In fact, that’s why they always used the term “center of pressure” (on the bottom of the wing) instead of center of lift (on the top surface).

In their 1906 patent they stated that their aircraft were “…supported in the air by reason of the contact between the air and the under surface of one or more aeroplanes [wings], the contact surface being presented at a small angle of incidence to the air.” They thought the only purpose of camber was to allow the wind to impact the forward upper surface of the wing to keep it from flipping over backwards. They held this erroneous belief for years after creating their powered airplanes.

Chapter 8: "'We Now Hold All Records!'"

Page 175: The author claims that the moveable rudder “provide[s] another instance of the presence of visual thinking in the Wrights’ inventive method.” Unfortunately their “visual thinking” did not recognize the problem of warp induced yaw beforehand, and that the fixed rudder, which they tried first, would make the problem worse.

Chapter 9: "The Dream Fulfilled"

Page 184: Yet another example of careless research is the claim that, in the Wrights’ first patent granted in 1906 “No mention of power is made in the claims.” In fact on page 1, lines 12-15, the patent states “….[the] aeroplanes [wings] are moved through the air edgewise at a small angle of incidence either by theapplication of mechanical power or by the utilization of the force of gravity.”

Page 186: Another try at belittling Octave Chanute is made by claiming that his statement that three-axis control was “ancient and well known” showed “almost unfathomable ignorance on the part of Chanute.” This claim actually shows “unfathomable ignorance” of the history of flight by a Director of the Smithsonian’s National Air and Space Museum. The concept of three-axis control was evident in a few glider concepts and vehicles, including Professor John Montgomery’s in the 1880s and going as far back as Le Bris’ 1857 glider which had wing warping and moveable horizontal and vertical tail surfaces. Moreover, the argument can be made that the Wrights didn’t actually have three-axis control until 1905 since their earlier vehicles all had vertical rudders only as an adjunct to wing warping to make the roll control work as intended. Those vehicles could only erratically control pitch and recover from inadvertent rolls, but could not intentionally execute turns.

The 1857 flight patent by Jean-Marie Le Bris

Page 189: We are told how Wilbur and Orville “cleverly used their tables…and lift and drag equations to determine the ….power requirements for the aircraft.” Unfortunately they were only “clever” enough to do it for level ground skimming flight. They did not heed warnings going all the way back to Cayley a century earlier, that an airplane would need additional power for taking off and climbing away from the ground. As a result, their aircraft could not “raise itself by its own power into the air” as they so proudly claimed in their post-1903 statements. In fact, their airplanes could not climb out of ground effect until 1905, and could not achieve flight without the help of strong headwinds or a catapult until late 1910, long after numerous other aircraft were routinely doing so.

Pages 194-198: On these pages the Wrights are lauded for making the “intellectual leap” that a propeller was just a wing moving in a spiral pattern and thus needed to be made up of cambered sections twisted as they went out from the hub to account for their increasing speeds through the air. Actually, this exact concept was presented to the Aeronautical Society of Great Britain in 1885 by Sidney Hollands and published in the U.S. by Chanute in February, 1893. (See the previous article Propelled to Absurd Heights by Paul Jackson in the January 26th, 2020 posting of this blog.)

 
Sidney Hollands, pioneer of the modern propeller

In fact, Hollands went the Wrights one better by also pointing out that the blades should be tapered as they progressed out from the hub to minimize bending loads and aerodynamic tip losses. It was primarily the increasing blade widths of the Wrights’ propellers that limited their efficiencies to around 65 percent. It may well also be this excessive tip loading that contributed to one splitting and causing Orville to crash during a 1908 demonstration at Ft Myer, killing Lt. Tom Selfridge and braking Orville’s back.

Page 206: The assertion is made that the Wrights use of a 60-foot launching rail would “make it clear that the [1903] takeoff[s] had been unassisted, allaying any possible doubts that the Flyer had made a true flight.” However the author says nothing about the fact that at Kitty Hawk, on the morning of December 17th, 1903, the 27 mph headwind with gusts even higher, supplied at least 90 percent of the airspeed, and over 80 percent of the lift required to get the Flyer into the air. It was almost flying sitting still without the engine and propellers turning. In fact, later that day the unattended vehicle did just that, the wind raising it up and rolling it over, destroying it. It would seem this wind constituted an essential assist and could raise, in Jakab’s words, “doubts that the Flyer had made a true flight.”

Chapter 10: "The Meaning of Invention"

Page 213: Although previous chapters lauded the Wrights’ “three-axis control” as enabling their 1902 glider to make turns, here that is directly contradicted by stating that “Before marketing their invention was possible, they would have to be able to make turns”. The author correctly points out that this was the purpose of their testing in 1904 and 1905 at Huffman Prairie, seemingly oblivious to the fact that he has made yet another contradiction within his own book.

l to r: 1902 Wright glider, 1903 Wright flyer, 1905 Wright flyer

Page 217: After spending the whole book describing the Wrights’ fabulously inventive genius, the book winds up by saying on the last page that “with the exception of the propellers, there was nothing fundamentally original about the way in which the 1903 machine was designed”. But as a last treat, two paragraphs down the author yet again demonstrates a somewhat schizophrenic style by following that statement with “they invented a fundamentally new technology.”

Summary

At this point I am somewhat at a loss for words to conclude this review. Not only is this the most inaccurate and confused book on the Wrights I have ever read, it is also possibly the most inaccurate record of technological history. And it was written by an Associate Director of the World’s premier aviation museum along with the help of some supposedly qualified technical contributors. Possibly some pressing deadline was imposed on the book preventing any real research. Or perhaps the intent was to do America a service by deifying two of its favorite sons. But still, these would not explain the numerous contradictions.

The real shame is that so many of the errors in this book have become part of the accepted historical record, and been repeated many times over, for decades, in subsequent books and media. This book seems to be yet another example of authority trumping truth.

--Joe Bullmer

 


Sunday, June 27, 2021

The Wrong Wright Story Series - Visions of a Flying Machine I


The Wrong Wright Story 2

Peter Jakab's Visions of a Flying Machine

Part II of a critique by Joe Bullmer


Left: Peter L. Jakab of the Smithsonian Institution; Right: Jakab's book Visions of a Flying Machine

Introduction to the Wrong Wright Story series:

This is the second in a series of critical reviews of four books and a television documentary about the Wright brothers’ creation of an airplane. The books include a biography authorized by Orville Wright, and three more by senior officials of the Smithsonian’s National Air and Space Museum. This article refers to the paperback reissue of Visions ofa Flying Machine by Associate Director Peter Jakab, published in 1990 by the Smithsonian Press, ISBN 1-56098-748-0.

These books were chosen because they have been used as source material for dozens of other publications containing discussions of the Wright brothers’ work and accomplishments. The NOVA documentary Wright Brothers' Flying Machineis perhaps the most prominent of approximately a dozen produced since 2003 portraying the invention of the airplane.

These five accounts all contain numerous fabrications and false statements that contradict the Wright brothers’ original records, the records of other aviation researchers who preceded the Wrights, and even aviation science. Unfortunately, other authors have relied on these books as bases from which to launch into discussions of the Wrights’ work. As a result, nearly every source of information on the Wright brothers’ work is contaminated with some of these same falsehoods and errors.

This series of articles represents an attempt by this author to establish “truthinaviationhistory” concerning the work of the Wright brothers. With this goal in mind, any technically qualified rebuttal to these critiques, or criticism of The WRight Story, would be welcomed.

Visions of a Flying Machine: Overview

It may seem unlikely that a book with such an extensive list of contributors in its Acknowledgements section as Visions would contain so many errors. However, only three contributors are credited with technical qualifications. One of these made similar errors in his books, which subsequent articles in this series will reveal. The others have published only limited writings on the Wright brothers, indicating only limited research.

A couple years of researching thousands of pages of original records of the Wrights and their predecessors resulted in my publishing a book in 2009 titled The WRight Story. Reliable primary and secondary sources were consulted for historical events preceding the Wrights and those after 1905. However, only original Wright material was consulted for all descriptions of their work resulting in a successful airplane by October of 1905. Surviving authors and producers of the works discussed in these reviews were contacted in an effort to discuss and resolve differences, but none have expressed interest in pursuing a dialogue.

A first reading of the book being discussed in this article revealed over 160 exaggerations or errors. Just addressing the 43 listed here precluded citing complete sources for each comment. However, eliminating more would be an injustice to portraying the nature of the book.

Chapter 1: "Why Wilbur and Orville?"

Page 15: The author claims “The majority of the critical elements in the airplane were original to the Wrights.” Actually, Wilbur admitted that the truss biplane structure was copied from the Chanute/Herring glider, their successful post-1902 wing camber and aspect ratios were essentially those used by numerous predecessors, and wing warping had already been used and patented by at least three experimenters. Cambered twisted propellers had also been recommended by a few predecessors, and even the forward elevator was a feature of Maxim’s 1894 machine. The only feature “original to the Wrights”, opposable wing warping with a mechanically coordinated rudder, had to be abandoned by them in 1905 in order to make turns.

The Chanute/Herring glider

Page 16: Here he repeats, writing that “Much of what the Wrights accomplished was highly original.” These comments are the first examples of the author's frequent contradictions, since page 217 says that “with the exception of the propellers, there was nothing fundamentally original about the way in which (sic) 1903 machine was designed”. In a sort of double reverse, the next paragraph on 217 says “they invented a fundamentally new technology.”

Chapter 2: "Aeronautics before the Airplane"

Page 33: The author claims that “Using [Otto Lilienthal’s] data and tables, an experimenter could easily calculate the size wing required to support a given weight at a particular velocity.” Then on pages 143 to 149 he talks about how bad he thinks Lilienthal’s data was. This is another unresolved contradiction in the book.

Chapter 3: "'You Must Mount a Machine'"

Page 46: The author writes, “[Lilienthal] failed to see that [weight shifting] was a dead end as far as a large, powered aircraft was concerned.” Actually Lilienthal did not “fail to see that.” On page 284 of the current edition of his book Birdflight as the Basis of Aviation, Lilienthal pointed out that although wings twice as big would be more optimum for gliding, he felt he couldn’t safely handle gliders larger than about 160 square feet with just weight shifting. In the 1896 edition of James Means’ TheAeronautical Annual, Lilienthal reported that he was well aware aerodynamic methods would be necessary to control larger aircraft. In fact, he was collaborating with other German experimenters on the design of such controls and had begun experimenting with them. Some claim it was actually a failure of one of these devices, rather than a piloting mistake, that resulted in his fatal crash.

Left: Lilienthal's Birdflight as the Basis of Aviation; Right: Chanute's Progress in Flying Machines.

Page 48: Here the Wrights are given credit for being the first to realize that control was the most important problem to solve. But in his 1894 book Progress in Flying Machines, the Wrights’ principal research source, Chanute stated that experimenters should direct their attention to gliding or “soaring” flight, and that the “maintenance of equilibrium….was by far the most important aspect of flight yet to be solved”. Nonetheless, in the book under discussion, this author goes on to say that “The Wrights’ recognition of the centrality of control…was…the premier conceptual leap that set them apart from their predecessors and their contemporaries.” He apparently has no idea that they read it in Octave Chanute’s book.

In the next paragraph, Alphonse Penaud is given credit for developing dihedral for roll stability during the 1870s. Yet again a lack of research is evident. Sir George Cayley invented dihedral and reported on it in the November, 1809 issue of Nicholson’s Journal of Natural Philosophy, Chemistry, and the Arts.

Page 49: The careless claim is made that “proponents of inherent stability gave no thought whatsoever to controlling or steering their machines.” adding “Many reasoned that if simple straight-line flight was achieved, control could be easily dealt with later.” This completely misses the fact that that is precisely the approach the Wright brothers took, concentrating solely on achieving straight line flight until 1904, then beginning attempts at maneuvering and turning, finally accomplishing these by October, 1905. They stated this many times, even in their patent, wherein on page three, lines 78 to 87, they explained that their moveable coordinated rudder was invented to maintain straight and level flight.

Page 50: In the second paragraph a severe lack of knowledge of aircraft design is exhibited by the author. He states “The Wrights were the first to see that control was [for airplanes] the very essence of maintaining equilibrium.” Actually, until recently all airplanes have been designed such that, once trimmed, they maintain equilibrium completely by their aerodynamic design without any control movements whatsoever. This was true of airplanes immediately following the Wright Flyers, and is largely what caused the Wrights to eventually totally change their designs not long before going out of business.

Later in the paragraph the author's lack of knowledge is confirmed by saying “…just as a cyclist must make constant control movements to stay on two wheels, the airplane pilot must exercise similar authority over his craft to stay in the air.” Anyone who has ever flown in an airplane, or even seen a film of a pilot flying one, should know this is not true. Even more astounding is the number of “aviation historians” that have confidently parroted these absurd statements in their books and TV appearances.

Page 51: The Wrights’ experience of riding bicycles is given credit for the idea of banking an airplane in order to turn. This is another fallacy that has been picked up by countless authors and “aviation historians.” It’s quite likely that some cavemen, over 100,000 years ago, noticed that birds always bank when they turn.

Page 58: Here and on the next page indecision is expressed as to whether or not the Wrights copied the trussed biplane design of the Chanute/Herring glider of 1896. Again, lack of research glares out. The Wrights both said they did! In a December 21st, 1909 letter 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 [wings].” Explaining their design in his sworn deposition for the 1920 Montgomery case, Orville testified that “it was apparent that the wings of a Chanute double-deck type [of glider] could be warped.”

Octave Chanute and his 1896 "double-decker" (as the Wrights called it)

Chapter 4: "Learning the Art of Airplane Design"

In this chapter, the book’s author, a history and arts major, attempts to explain key aerodynamic and stability and control aspects of aircraft design. Only major errors are discussed here. There are many others.

Page 65: At the bottom of the page he writes, “Although the record shows little specific discussion of these issues by the Wrights before 1901, it is clear….that they had at least a basic understanding of the reversal of the center of pressure before building their first full-size machine.” (Although he cites two references in the Notes section of his book for this statement, examination of the references reveals no justification for such a statement.)

On the next page he reverts to his favorite theme of Wright perfection, saying “Just as their initial instincts…regarding control moved them well ahead of their contemporaries, so too did their beginning assumptions concerning aerodynamics.”

Actually, both brothers recorded statements directly admitting that their canards (forward elevators) were the result of their erroneous concept of the movement of the center of pressure on a wing. During his speech in Chicago in 1901 Wilbur stated, “Our peculiar plan of control by forward surfaces instead of tails was based on the assumption that the center of pressure would continue to move farther and farther forward as the angle [of attack] became less”, an assumption that proved to be false. In his legal deposition of 1920, Orville recalled their perplexity thus: “Our elevator was placed in front of the surfaces [wings] with the idea of producing inherent stability fore and aft, which it should have done had the travel of the center of pressure been forward [with decreasing angle of attack] as we had been led to believe.”

The author admits that he couldn’t find much about the Wrights’ knowledge of center of pressure movements before 1901. The reason is that they didn’t know how it moved until the summer of 1901 when Chanute’s cohorts Edward Huffaker and Dr. George Spratt demonstrated it to them through wing balance tests at Kitty Hawk. Wright statements reveal that the reversal of movement of the center of pressure came as quite a surprise to them. Evidently they had only seen data on flat surfaces and neglected to check cambered ones.

                         Visitors to Kitty Hawk. l to r: Huffaker, Chanute, Wilbur Wright, and Spratt.

This is a good spot to address the constantly repeated claims throughout the book that the Wright’s “intuition” or “instinct” about aerodynamics enabled them to “visualize” air flow correctly in their minds without actually seeing it. This ability is credited for their development of their 1900 and 1901 wing shapes which he repeatedly claims were very good. He later contradicts these statements by blaming Otto Lilienthal’s data for these two vehicles having totally inadequate lift.

In fact, these vehicles could barely fly, and the Wrights’ wind tunnel showed them they had to change wing camber and aspect ratio to something very similar to Lilienthal’s (and numerous other predecessors) which solved their lifting problems. In a November 24th, 1901 (i can't find this letter) letter to Octave Chanute, Wilbur admitted that “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.”

Other examples of the Wrights’ “instinct” for aerodynamics failing them, but not noted in this book, were not seeing

  • How cambered wings generate lift.
  • That an airplane needs tails to be easily controllable.
  • How wing warping would work in free flight.
  • That a fixed vertical tail wouldn't stop their warp-induced spins.
  • That stability and insensitivity to crosswinds were opposing goals.

Page 66: We are informed that when the center of pressure and center of gravity coincide, an airplane is at equilibrium. Instantaneously, yes. But practically, equilibrium implies stability at that point, i.e., the airplane should want to stay there. That requirement is something that eluded the Wrights, and evidently also the author of the book being discussed.

Page 67: Here he states that Horatio F. Phillips’ 1884 airfoil shapes set the precedent for the Wrights’ early airfoils. One can only conclude that he has never seen Phillips’ airfoils because some of them look quite modern, and all had maximum cambers at least a third of the way back, as opposed to those of the Wrights in which maximum camber was located immediately behind the leading edges.

Horatio F. Phillips' patented airfoil shapes

The author goes on to incorrectly discuss camber as if it was only “the [maximum] depth of the curvature” as opposed to the entire curvature of the wing from leading to trailing edges, including the critical location of maximum camber.

Page 68: Again, reality is contradicted here by saying that the Wrights’ early wings, with maximum camber right behind the leading edges were a “marked improvement in aerodynamic efficiency over the….wing used by Lilienthal and others” and “it also provided much more lift than the wings used by contemporary glider experimenters.” (Here again a source in his Notes section of the book is referenced that has nothing to do with his claim.) Contradicting this on pages 154 and 155 the author admits that their 1900 and 1901 wings were terrible and the wind tunnel showed that they had to move maximum camber much farther back and increase aspect ratio (more than doubling it to Lilienthal’s value) to obtain reasonable lift for their 1902 glider.

Page 69: He attempts to explain the “Penaud” method of achieving longitudinal stability but gets it exactly backwards by saying Penaud set his horizontal tails at a positive angle of attack. His explanation of how this would work is incoherent since it can’t work. In fact, Penaud set them at negative angles of attack to balance out the centers of gravity which were placed ahead of the centers of lift to achieve dynamic stability. With this, if the aircraft pitched nose up, Penaud’s negative tails would have a less negative angle to the wind and push down less, allowing the forward center of gravity to pull the nose back down. If the aircraft was pitched nose down, the tails would have a more negative angle, push down harder, and bring the nose of the vehicle back up.


                     Penaud's "aeronautical machines:" helicopter, planophore, and ornithopter.

And by the way, this author, like most all others, erroneously credits Penaud with originating this method of achieving stability. Sir George Cayley reported on using it for his unmanned gliders in Nicholson’s Journal in 1809.

Later on this page the author reveals the falseness of his assertion on page 65 that the Wrights knew about the reversal of movement of the center of lift (pressure) when they started. He says here that they “designed their forward rudder [canard] as if they were dealing with a wing having the properties of a flat plate,” i.e., no reversal of travel of the center of lift with angle of attack.

Page 70: Here he says “the Wrights’ scheme of a moveable elevator to keep pace with a constantly roving center of pressure was fundamentally sound, and it has been the method for pitch control on virtually every airplane since.” Yet again ignorance of aircraft design, and even flying, is revealed by not knowing that airplanes, once the horizontal stabilizer is trimmed out, do not need any help from an elevator to maintain longitudinal balance. A proper understanding of the “Penaud” technique would have revealed why.

Page 71: The author states that a canard stalls before the main wings because of its smaller size and thus avoids stalling of the wings which he implies is a stabilizing effect. Thus, two mistakes for the price of one. First, nothing stalls because of its size. It would stall first because of lack of camber or higher angle of attack, but not because it was smaller. Also, their canard is what made the airplane unstable and caused it to depart from level flight in the first place. It was therefore destabilizing.

Page 75: It’s asserted here that the Wrights didn’t put a vertical tail on their gliders for the first couple years because “it would complicate matters unnecessarily.” No, they didn’t think one was necessary because they were only trying to fly straight, and their aerodynamic “instinct” didn’t tell them about wing warping creating asymmetric drag which yawed their airplane. That’s why a rudder was required; to maintain the original heading.

In fact, in his speech in Chicago in 1901 Wilbur erroneously stated that “tails, both vertical and horizontal,..…may with safety be eliminated.” He then proceeded to design their next machines with vertical tails.

Page 78: Here the author explains the lift and drag equations as though lift and drag coefficients are the same for all wing shapes. Actually, until November of 1901 the Wrights thought so too.

Page 81: The bizarre tutorial on aerodynamics and airplane design is wound up by again admiring the Wrights’ supposed ability to mentally visualize aerodynamics, which, as previously noted, was often wrong. 

Conclusion - Part I: 

At this point the first four chapters of the book Visions of a Flying Machine have been discussed. Due to the length of this critique the remainder will be discussed in the second part appearing shortly in truthinaviationhistory. That part of the article will begin the discussion of Chapter 5 with a list of ten seldom noted, but well documented, significant contributions to the Wright effort by Octave Chanute, without which the brothers' achievement of success would have been problematic.