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Lot #184
Ettore Bugatti Archive: Typed Letter Signed on 500-HP, 16-Cylinder Engine, with Photographs and Supplements

Important archive of Bugatti materials on his giant 500 horsepower, 16 cylinder engine—licensed to Duesenberg for American production

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Description

Important archive of Bugatti materials on his giant 500 horsepower, 16 cylinder engine—licensed to Duesenberg for American production

Italian-born French automobile designer and manufacturer (1881–1947) celebrated as the founder of Automobiles E. Bugatti. Archive of material by and related to Ettore Bugatti, highlighted by a four-page TLS in French to the director of Duesenberg in Elizabeth, New Jersey: TLS signed twice by Ettore Bugatti, and also initialed by him at the foot of the first two pages, four pages, 8 x 10.5, personal stationery, April 11, 1918, in part: "As regards the changes made to my engine, I regret that these were made without prior notice. I have no intention of calling into question the ability of the engineers who carried out these transformations, and I simply limit myself to giving my opinion.

I. The mixed lubrication under pressure and by centrifugal force of my engine has been eliminated by a lubrication under pressure. It is possible that you have a satisfactory result, but I consider my device as being more certain.

2. Transformation of water jackets: you will certainly have some difficulties with the autogenous welding process. I myself studied this device three years ago, and I had to abandon it.

3. The upper part of the cylinder, cast with the cylinder itself, is part of my construction of series cars, which I have been manufacturing for about ten years and which I have left for many reasons which are very difficult to communicate to you personally.

4. The modified water circulation device: in fact, the water enters from the propeller side into the cylinders; after cooling the first group of cylinders, it passes into the 2nd group and exits at the rear, on the water pump side. When the engine is put into the up position, you will have pockets of vapor that will form and that will completely disturb the water circulation, compromising the efficiency of the cooling.

To avoid this disadvantage, you could have the water enter the cylinders on the water pump side and leave it in the cylinders on the propeller side, because the front cylinders cool more than the rear cylinders in the machine…

5. You have rounded the corners of the cylinders. Please find enclosed a photograph of a car that I built about 10 years ago and it will be easy for you to see that the corners are rounded as you must have done and with fewer bolts for their attachment to the crankcase. Construction that I abandoned to replace it with the existing system on my engine. I was led to make this change, following long experiences.

6. The exhaust and intake sections are rounded. You must have seen that, for the same passage, you were obliged to raise the cylinder. As a result, an increase in weight. I am against the theory which admits that a gas passage must be round instead of being square. It is simply a matter of its opening being proportionate to the work that the engine must do, to have no difference in efficiency. I add, in parentheses, that the efficiency that I obtained with this engine is superior to anything that has been obtained, even with racing car engines, considering the number of revolutions, and the volume of the cylinders.

7. For the crankshaft, the rounding that you have done is a completely natural thing, but it was not done in Europe, because we are not able, here, during the war, to forge the parts as you forge in your factories. This rounding would have required an additional machining operation.

8. The carburetor piping heated by the water circulation will certainly give you trouble. The seal between the cylinder and the pipe is difficult to obtain, and it will happen, as a result, a suction of water into the intake valves. Which will cause you serious inconvenience.

9. The transformation that you were able to make to the piston must be considered as a very delicate thing, because the aluminum piston is unergonomic very difficult, and it was in my construction the object of long tests….

The central bearing on the crankshaft is the summary of long studies. I have always made engines with camshaft on top. Therefore, I studied all the means of fixing this bearing, and the one-piece bearing with the crankcase gave me very great difficulties. It is necessary to consider the support of the bearing in forged steel, as being of very great importance and a safety of operation

In principle, it is always possible to change, especially in its appearance, an engine, but it should not be overlooked that these engines, in 8 and 16 cylinders, have carried out their official 50-hour test, the results of which have been most satisfactory, and it is certainly imprudent to make changes, before having tried these modifications, on engines of the same type, built after the original.

The tests must be made with a propeller, and the power curve with a four-bladed reel. This reel must be made of several thicknesses of glued wood, to avoid unbalancing due to the difference in density of the wood used…A motor should never be tested with an electric brake; this would be to sacrifice this motor to a breakage, by making it support a work which is not appropriate for it, given that it must have a mass which serves as a flywheel identical to that which is mounted in an airplane, by the fact of its propeller. No test has ever been successful on an electric brake or on a hydraulic brake, unless proceeding with cooling of the crankcase and of all the artificial parts." He goes on to define his engine's power curve, which tops out at 527 horsepower.

On the last page, Bugatti continues: "During the winter, the oil will be heated before starting. During the summer, it is necessary to have a cooling of the oil. It is essential not to exceed 65 0 70 centigrade, at the outlet from the engine housing.

Carburetors and intake pipes: I have learned that the heating of the intake tube is being considered, not by heating as had been planned, but by water circulation. The greatest attention will be paid to the possibility of a leak inside the tubes.

Carburetors must be warmed up very vigorously. A temperature of 80 is a minimum. You can certainly get the same engine performance with a lower temperature, but cause gasoline condensation, which forms gasoline threads in the pipe, and consequently, leads to overheating of the internal parts of the cylinder, such as the spark plugs and valves: the exhaust valves would eventually become deformed."

Additionally includes two related unsigned pages on Bugatti's personal stationery, conveying some information about his engine with details on its cylinders, exhaust pipe, spark plugs, fuel lines, and oil circulation; the second page boasts original hand-drawn sketches of setups for the gasoline and oil filters.

Further accompaniments are a manuscript page in French on Duesenberg Motors Corp. letterhead pertaining to the "moteur 500 HP," a letter regarding the manufacture of the King-Bugatti engine, and eight original vintage glossy photographs, all about 2.5 x 4, one showing Ettore Bugatti as part of a group, and the others showing his 500 horsepower, 16 cylinder aviation engine. In overall fine condition.

These materials pertain to Bugatti's powerful piston aircraft engine, the Bugatti U-16, and its American-made successor. The Bugatti U-16 was a 16-cylinder water-cooled double-8 vertical in-line 'U engine' designed by Ettore Bugatti in 1915 to 1916 and built in France in small numbers. The Bolling Commission bought a license to build a version of the engine in the United States, with modifications made by Signal Corps aeronautical mechanical engineer Colonel Charles Brady King. Small numbers of this slightly revised version—approximately 40 engines—were built by the Duesenberg Motor Corporation as the King-Bugatti. About 40 of these King-Bugatti engines were made before the end of World War I caused building contracts to be canceled.

Auction Info

  • Auction Title: Fine Autograph and Artifacts
  • Dates: #701 - Ended October 16, 2024