Repair Manuals And $10 - Wednesday, November 12, 1902
The History: Wilbur responded to Octave Chanute's letter of November 5th. In regards to Hargrave's question on steam motors, Wilbur replied neither he nor Orville had studied the subject. Unfortunately, the brothers do not feel they can supply Hargrave with any information or even recommend a book. One thought: perhaps the Locomobile Company publishes books on the repairs of their motors, which would provide Hargrave with a description of the motors or possibly furnish the information he seeks.
Wilbur informs Chanute that a few days before the brothers finished their Kitty Hawk experiments they received a telegram and then a letter from Samuel Langley. Langley asked if he could visit the camp and watch some of their gliding experiments. The brothers replied it would not be possible since they would be "breaking camp" and returning home very shortly. Wilbur mentions to Chanute that Langley did not mention his own flight experiments conducted on the Potomac River.
Wilbur includes some photos of their glides for Chanute.
Wilbur explains to Chanute, Orville "is at work on a new testing machine" [wind tunnel equipment to test wing shapes]. The brothers may decide to run additional tests similar to those conducted in 1901. He relays to Chanute: perhaps he should wait to do the computations on the old data.
Wilbur responds to a letter from their friend and fellow experimenter, George Spratt. Spratt had written to the brothers on November 7th, humorously telling them how he had to fight off bedbugs the night he spent at Dr. Cogswell's [of Kitty Hawk] guestroom on his return home.
Wilbur encourages Spratt to pursue his latest technical "bright idea". Wilbur feels that this could lead to some valuable information. If any of the information the Wrights have access to will help Spratt they would be happy to share it with him.
Wilbur describes their glides during the 3 days after Spratt left. They made 150 glides one day and about 100 the next. He recounts the same information on "gliding records" he described to Chanute.
Wilbur shares the brother's escapades traveling home. Leaving their campsite on Tuesday, Oct. 28th, they walked [4 miles] from Kill Devil Hills to Kitty Hawk in a "cold drizzling storm blowing over 30 miles per hour". They sailed on the schooner the Lou Willis but by dark had not traveled very far. Captain Midgett decided to turn back and anchor at Powell's Point for the night. The following day, the winds remained high and Captain Midgett elected not to sail that day. At noon, the Wrights transferred to another boat, the Ray. After what Wilbur referred to as a "very rough trip" they finally reached Elizabeth City at 8:45 PM. Wilbur calculated they had only traveled 1 mile per hour for the last 36 hours or 36 miles the distance from Kitty Hawk to Elizabeth City.
Map of the North Carolina Outer Banks
In his letter of November 7, Spratt had enclosed $10 to cover his camp expenses at Kitty Hawk. Wilbur relates to Spratt they did not accepted payment from the other camp visitors (their older brother, Lorin, Octave Chanute, Augustus Herring). Spratt's assistance at camp more than compensated for any board [daily meals]. Wilbur will return the check.
Wilbur enclosed tables of lift (charts of pressure [force per area] at right angles to the wind) - results of their 1901 wind tunnel tests. On the back of the tables Wilbur had placed descriptions of the airfoil surfaces tested in the wind tunnel. These were the results from their wind tunnel tests . Wilbur referred to the tests as "artificial blasts" [of air] moving at about 30-35 miles/hour. He promised to send Spratt "the resolutions of the forces and names of the forces" when he sketches them out.
Many years later this letter would be entered as evidence in a legal court case (Montgomery versus the United States) as proof of the Wrights' development of the airplane.
Although Wilbur conveyed to Spratt that wind tunnel speeds were in the range of 30-35 miles per hour. Today, some experts believe that the tunnel wind speed was less than this, perhaps only 20 miles per hour.
Understandably, early (1900) and modern aerodynamics differ. Today's aeronautical engineers have a century of successful tests, research and aircraft performance to support modern theory. During the early years of aviation, the term "lift" referred to a force going straight up and opposing gravity. Today, lift is defined as the force at right angles (perpendicular) to drag (or the incoming wind). Only in straight and level flight is lift straight up. The Wrights lift balance measured this force at right angles which was called "false lift" or the rectangular pressure. Wilbur has promised Spratt that he will provide him a description of these forces in future correspondence.
It is interesting to note the tone of the letters between the Wrights and George Spratt versus Octave Chanute. Wilbur's letters to Chanute are much more formal and prosaic, while letters to Spratt are light hearted; their friendship for Spratt is obvious.