Wilbur Wright to Octave Chanute

Dayton, July 24, 1903

Your special delivery letter of 23rd inst. is at hand and I hasten to reply.

The vertical tail is operated by wires leading to the wires which connect with the wing tips. Thus the movement of the wing tips operates the rudder. This statement is not for publication, but merely to correct the misapprehension in your own mind. As the laws of France & Germany provide that patents will be held invalid if the matter claimed has been publicly printed we prefer to exercise reasonable caution about the details of our machine until the question of patents is settled. I only see three methods of dealing with this matter: (1) Tell the truth. (2) Tell nothing specific. (3) Tell something not true. I really cannot advise either the first or the third course. If the entire last sentence in the upper paragraph on page 14 is omitted no embarrassment would result so far as I can see.

There is another matter that possibly I should take up now, rather than later. You remember doubtless that Orville and I have always discouraged computations based on glides and that we have never offered any comparative computations of different machines. The comparisons that have been made have been on figures offered by Messrs. Huffaker, Herring, or yourself. We have considered it a dangerous topic and in our published papers have not made any comparisons except in the matter of size. We did not feel that it would be fair to attempt close comparisons of glides made under widely differing conditions. The chance of grave error is too great. To convince you of this, I will now offer a sample computation using, as nearly as I possibly can, the methods used by you in preparing the table at the close of your Revue article.

I will compare your "double decker" with our 1902 machine. As I understand it your figures for our machine are based on an average of our results, and the figures for your machine on the glide described by Mr. Herring (Aero. Annual. 1897, p. 69) when there was "merely a trace of wind from the northeast," the flight being to the north. I will accordingly take an average of the 4 glides given on page 42 (Aero. Annual. 1897) 2 using a wind speed of 22.3 miles (18.1 miles corrected) which is the amount which I find you have inserted in our book at that place. And for our machine will take the glide #24 which was made under conditions similar to those described by Mr. Herring, the wind being very light.

The results are as follows:

Lbs. per horsepower

If you will compare with the figures in the Revue article you will note a difference of more than "50 percent." Of course I do not claim that the figures here given are fair except in the same sense that the Revue figures are fair. I merely wish to impress the danger of attempting public comparisons with insufficient data, and different conditions of comparison. I steer clear of them.

Octave Chanute to Wilbur Wright, July 27, 1903