'We are always pleased when you ask for information' - Wilbur Wright letter for sale

Addressed to one of America's great pilots, the text explains in detail how to use their plane

As we've reported, RR Auction's space sale (ending September 15) includes several top-notch pieces of memorabilia from mankind's steps towards the stars, notably a Neil Armstrong training glove and a lunar-landed microfilm bible.

It isn't strictly just collectors of space missions who will be excited by the auction however, but collectors of mankind's earlier quest to leave the ground at all. One classic item from this struggle is a letter from one of the Wright brothers: Wilbur Wright.

Specifically this is a typed letter, signed by Wright, spread across two pages with The Wright Company letterhead dated November 10, 1911. It is addressed to Lieutenant H. H. Arnold. An extract reads:

"Your letter of recent date seems to have disappeared and it is possible that it is lying at Kitty Hawk. I am answering the main points of the letter as I remember them.

"The screws on the 'B' machine should run inside a closed shed 425 turns per minute. With an old motor in good condition they have been run more than 440 turns per minute. If the result is below 410 the motor is palpably in need of attention.

"Each five turns per minute indicates a difference of one horse power, but as the screws may vary a trifle after they have been out a while, a variation of five is not abnormal. The motors gain in power as they become older if well cared for, the gain at the end of the year being about three horse power.

All the nuts and bolts - the Wilbur Wright letter

"It is very important that the motor should never be run without plenty of water in the radiator, and oil in the tank. If the motor overheats the cylinders warp a trifle and a month may elapse before the motor again comes up to the old mark."

Wright continues with more details before cordially signing off:

"I do not remember any other points upon which you wished information, but we are always pleased to have you ask for any needed information and to have you tell us from time to time what things about the machine you find unsatisfactory, or capable of being changed to afford better satisfaction."

The letter is highly desirable artifact linking 'Hap' Arnold, one of the Army's greatest pilots and Wilbur Wright, who would die from typhoid fever just six months later. Bids open at $1,000, but it will be the bargain of a lifetime for anyone who buys it around that price.

Items associated with both brothers or Wilbur in particular can be very valuable, such as the very first company cheque signed by them, which is currently available elsewhere on the markets.