CHAPTER VII
DEVELOPMENT OF THE LIBERTY AND OTHER MOTORS
DEBATE IN REGARD TO ORIGIN OF LIBERTY MOTOR—LIBERTY-ENGINE CONFERENCE, DESIGN, AND TEST—MAKERS OF PARTS—HISPANO-SUIZA MOTOR—ROLLS-ROYCE—OTHER MOTORS
Therehas been more discussion of the Liberty motor than any other motor made during the war. This was due to the publicity given to the motor by the publication of a romantic story of the motor, issued from Washington over the signature of Secretary of War Baker, to the effect that the motor was conceived in a few days, and built and perfected within a month. Of course every engineer knows that that could not be done, and it took at least six months before the Liberty engine was perfected, and this was long after the Creel Publicity Bureau in Washington issued its statement.
As we have pointed out elsewhere, if the Aircraft Production Board had taken the patterns of a standard motor like the Hispano-Suiza, which had been flown for nearly three years under all kinds of war conditions, and which was being built in this country, and if they had ordered gigs, dies, and tools, and when we entered the war had requested our engineers tofollow Chinese patterns in the making of the same, the dies, gigs, etc., could have been made at once instead of months later, and many American-made aircraft could have been operating over the lines when the Americans began to fight at Château-Thierry, and not months later, as was the case. Undoubtedly this delay cost the lives of thousands of American soldiers, and set back the Allied victory by just so much. The failure to deliver aircraft on schedule was the reason why General Pershing had to demand haste in the production of machines. Regardless of the fact that the aeroplane motor is radically different from the automobile motor, because it must be much lighter, nevertheless automobile men were called in by the Aircraft Production Board to design the Liberty motor, and many of the engine-building companies that had been constructing aeronautical motors were not consulted.
After the Liberty engine was completed a lively debate was instituted as to which of the two companies that was represented at the designing of the engine deserved the most credit for the job. One of the automobile companies advertised the fact that they were responsible for the Liberty motor, and the other company immediately replied, trying to prove that because they had built successful motors before the war that they were the real designers of the motor.
To be sure, no one would have objected to the construction of a Liberty motor on the side, but to delay the construction of motors in quantity until September, 1917, put the United States back just sixmonths in production, for a number of factories were already producing parts for Rolls-Royce engines, and the Wright-Martin Company had been building the Hispano-Suiza motor since January, 1916.
Be that as it may, the facts regarding the Liberty motor appear to be that General Squier, E. A. Deeds, Howard E. Coffin, S. D. Waldon, of the Aircraft Production Board, called in to consultation on May 29, 1918, E. J. Hall, chief engineer of the Hall-Scott Motor Company, builders of a number of 4, 6, 8, and 12 cylinder aeroplane engines, and Jesse G. Vincent, experimental engineer of the Packard Motor Car Company, who had just completed a design and an experimental aeroplane engine, which had never up to that time been in a plane.
Both these gentlemen were in Washington attempting to interest Signal Corps officials in the aeroplane engine each had designed.
Liberty-Engine Conference
A five-day conference between Mr. Hall and Mr. Vincent, called by Mr. Deeds and Mr. Waldon of the Aircraft Production Board to consider aeroplane-engine design and production, was held. The two engineers got together in designing a standardized, directly driven, five-bearing crank-shaft engine of 8 cylinders, and one of 12 cylinders, with a seven-bearing crank-shaft. After a session of twenty hours’ work in a room at the New Willard Hotel, in Washington, during which meals were served the two men,and both lived, worked, and slept in the apartments of Mr. Deeds, a new 8-cylinder 230 horse-power aeroplane engine was laid out, described, and drawings of transverse and longitudinal sections were made by Vincent and Hall themselves. This was the first Liberty motor designed.
On the morning of May 30, 1917, near the close of the designing session, Mr. Vincent dictated a joint report to the Aircraft Production Board. The salient points and a rough draft had been agreed upon the night before. It was dated May 31, 1917, and signed jointly by E. J. Hall and Jesse G. Vincent.
Washington, D. C., May 31, 1917.Aircraft Production Board,Washington, D. C.Gentlemen: At your request we have made a careful study of the aircraft motor situation and hasten to submit our report as follows:In order to get this report in your hands promptly we have condensed it as much as possible and have covered the essentials only.In view of the fact that there are a number of good motors for training-machines available, we have disregarded this type of motor and have confined our attention strictly to the high-efficiency, low-weight per horse-power type, such as is necessary at the front.In order that any motors that are built by this country may be of any value when received at the front, it is, of course, absolutely necessary that their efficiency be brought up to or a little beyond the best now available in Europe. This, of course, made it necessary for us to know just what has been accomplished in Europe. The French and English Commissionhas enabled us to obtain this information by answering our questions very clearly and completely.From information obtained from these gentlemen and from other sources, we believe that the Loraine Dietrich is the coming motor in Europe. This motor has not been built in large quantities as yet, but some thirty had been constructed and carefully tested out at sea-level and also at about 6,000 feet elevation. The important facts about this motor are as follows:Eight cylinders: 120 mm. bore by 170 mm. stroke.Cylinders made of steel with water-jackets welded on. Motor is direct-driven and develops 250 horse-power at 1,500 r. p. m., and 270 horse-power at 1,700 r. p. m. The weight of the bare motor is 240 kilos, or approximately 528 pounds, while the weight of the motor complete with radiator and water is 305 kilos, or 671 pounds. There seems to be a reasonable doubt regarding the exact weight of the bare motor, as while the French Commission gave us the figure of 528 pounds, information from other sources indicates a weight of 552 pounds; probably some intermediate figure is more nearly correct, but in any event the motor gives a horse-power for approximately two pounds of weight when figured at its maximum output of 270 horse-power.After obtaining this information and considering the matter very carefully, we next investigated the matter of testing such a motor, as we knew that a motor of this type could not be run at full power for long periods of time without developing serious trouble. Here again the French Commission gave us valuable information. They stated that in using a motor of this type it is only run at full power for short periods of time while climbing or fighting, and that all other times it is run at speeds 200 to 300 r. p. m. slower. In view of the fact that the motor is built to run under these conditions, it is, of course, necessary to test it under similar conditions, and they stated when trying out a new model of motor it is their practice to mount a propeller which will just hold the motor down to maximumspeed under full throttle. The motor is then run for fifty hours, in periods of six to eight hours each, but the motor is not run up to full speed for more than a total of ten hours during this entire period, nor is it run more than thirty minutes at any single time under this condition. The other forty hours’ running is under throttled conditions, turning the same propeller 200 to 300 r. p. m. less than maximum speed.This information is of the utmost importance, as it enables us to reduce all factors of safety and make possible the light-weight per horse-power now being obtained in Europe.After obtaining this information we immediately laid down a proposed motor which we believe can be produced promptly in large quantity in this country. Built carefully out of proper materials, this motor will have approximately the following characteristics and be as good, or a little better, than the Loraine Dietrich, which is not as yet really available abroad.In laying down this motor we have without reserve selected the best possible practice from both Europe and America. Practically all features of this motor have been absolutely proved out in America by experimental work and manufacturing experience in the Hall-Scott and Packard plants, and we are, therefore, willing to unhesitatingly stake our reputations on this design, providing we are allowed to see that our design and specifications are absolutely followed.The motor is to be of the eight-cylinder type, with cylinders set at an included angle of 45 degrees. The cylinders are of the individual type, made out of steel forgings with jackets welded on. The bore is five inches and the stroke seven inches, giving a piston displacement of 1,100 cubic inches. The crank-shaft is of the five-bearing type with all main bearings 2⅜ inches in diameter, and all crank-pin bearings 2¼ inches in diameter. The connecting-rods are of the I-beam straddle type. This motor is of the direct-driven type with a maximum speed of 1,700 r. p. m. This motor will have a maximum output of 275 horse-power at 1,700 r. p. m. It will weigh 525 to 550 pounds,but we feel very sure of the lower figure. It will have a gasoline economy of .50 pounds of fuel per horse-power hour or better; it will have an oil economy of .04 pounds of oil per horse-power hour or better. Complete with water and radiator, this motor will not weigh more than 675 pounds, if a properly constructed radiator is used and placed high above the motor.To obtain the above-mentioned weights it will be necessary to use the fixed type of propeller hub which has been thoroughly proved out by Hall-Scott practice. In order to obtain the above-mentioned weights it will also be necessary, as mentioned above, to use the very best material, workmanship, and heat treatment.Complete detail and assembly drawings, as well as parts list and material specifications, can be completed at the Packard factory under our direction in less than four weeks. We believe that a sample motor can also be completed in approximately six weeks if money is used without stint. As soon as the drawings, specifications, and sample motor have been finished, complete information would, of course, be available so that any high-grade manufacturer could either make parts for this motor or manufacture it complete.In laying down this design we have had in mind the extreme importance of interchangeability, as a well-laid, comprehensive programme which has for its base interchangeability of important parts, such as cylinders, will speed output and reduce ultimate cost to an astonishing extent. Europe is suffering right now from lack of uniformity of design, but it is too late for them to change their plan. We, however, can take a leaf out of their book and start right.In the design which we have laid down, the cylinder, for instance, can be used to make four, six, eight, and twelve cylinder motors. As this is the most intricate part to make, immense facilities could be provided to produce them in large quantities for the use of many concerns who could manufacture the balance of the motor. Nearly all small parts and numerous largeand important ones would also be interchangeable. This would not only speed up production but would be of the utmost importance in connection with repairs and replacements. A full line of motors made according to this plan would line up about as follows:TypeRatedHorse-powerMaximumHorse-powerWeightWeight perHorse-power41101353752.761652054902.382252755351.9123354107101.7Respectfully submitted,(Signed)J. G. Vincent.(Signed)E. J. Hall.
Washington, D. C., May 31, 1917.
Aircraft Production Board,
Washington, D. C.
Gentlemen: At your request we have made a careful study of the aircraft motor situation and hasten to submit our report as follows:
In order to get this report in your hands promptly we have condensed it as much as possible and have covered the essentials only.
In view of the fact that there are a number of good motors for training-machines available, we have disregarded this type of motor and have confined our attention strictly to the high-efficiency, low-weight per horse-power type, such as is necessary at the front.
In order that any motors that are built by this country may be of any value when received at the front, it is, of course, absolutely necessary that their efficiency be brought up to or a little beyond the best now available in Europe. This, of course, made it necessary for us to know just what has been accomplished in Europe. The French and English Commissionhas enabled us to obtain this information by answering our questions very clearly and completely.
From information obtained from these gentlemen and from other sources, we believe that the Loraine Dietrich is the coming motor in Europe. This motor has not been built in large quantities as yet, but some thirty had been constructed and carefully tested out at sea-level and also at about 6,000 feet elevation. The important facts about this motor are as follows:
Eight cylinders: 120 mm. bore by 170 mm. stroke.
Cylinders made of steel with water-jackets welded on. Motor is direct-driven and develops 250 horse-power at 1,500 r. p. m., and 270 horse-power at 1,700 r. p. m. The weight of the bare motor is 240 kilos, or approximately 528 pounds, while the weight of the motor complete with radiator and water is 305 kilos, or 671 pounds. There seems to be a reasonable doubt regarding the exact weight of the bare motor, as while the French Commission gave us the figure of 528 pounds, information from other sources indicates a weight of 552 pounds; probably some intermediate figure is more nearly correct, but in any event the motor gives a horse-power for approximately two pounds of weight when figured at its maximum output of 270 horse-power.
After obtaining this information and considering the matter very carefully, we next investigated the matter of testing such a motor, as we knew that a motor of this type could not be run at full power for long periods of time without developing serious trouble. Here again the French Commission gave us valuable information. They stated that in using a motor of this type it is only run at full power for short periods of time while climbing or fighting, and that all other times it is run at speeds 200 to 300 r. p. m. slower. In view of the fact that the motor is built to run under these conditions, it is, of course, necessary to test it under similar conditions, and they stated when trying out a new model of motor it is their practice to mount a propeller which will just hold the motor down to maximumspeed under full throttle. The motor is then run for fifty hours, in periods of six to eight hours each, but the motor is not run up to full speed for more than a total of ten hours during this entire period, nor is it run more than thirty minutes at any single time under this condition. The other forty hours’ running is under throttled conditions, turning the same propeller 200 to 300 r. p. m. less than maximum speed.
This information is of the utmost importance, as it enables us to reduce all factors of safety and make possible the light-weight per horse-power now being obtained in Europe.
After obtaining this information we immediately laid down a proposed motor which we believe can be produced promptly in large quantity in this country. Built carefully out of proper materials, this motor will have approximately the following characteristics and be as good, or a little better, than the Loraine Dietrich, which is not as yet really available abroad.
In laying down this motor we have without reserve selected the best possible practice from both Europe and America. Practically all features of this motor have been absolutely proved out in America by experimental work and manufacturing experience in the Hall-Scott and Packard plants, and we are, therefore, willing to unhesitatingly stake our reputations on this design, providing we are allowed to see that our design and specifications are absolutely followed.
The motor is to be of the eight-cylinder type, with cylinders set at an included angle of 45 degrees. The cylinders are of the individual type, made out of steel forgings with jackets welded on. The bore is five inches and the stroke seven inches, giving a piston displacement of 1,100 cubic inches. The crank-shaft is of the five-bearing type with all main bearings 2⅜ inches in diameter, and all crank-pin bearings 2¼ inches in diameter. The connecting-rods are of the I-beam straddle type. This motor is of the direct-driven type with a maximum speed of 1,700 r. p. m. This motor will have a maximum output of 275 horse-power at 1,700 r. p. m. It will weigh 525 to 550 pounds,but we feel very sure of the lower figure. It will have a gasoline economy of .50 pounds of fuel per horse-power hour or better; it will have an oil economy of .04 pounds of oil per horse-power hour or better. Complete with water and radiator, this motor will not weigh more than 675 pounds, if a properly constructed radiator is used and placed high above the motor.
To obtain the above-mentioned weights it will be necessary to use the fixed type of propeller hub which has been thoroughly proved out by Hall-Scott practice. In order to obtain the above-mentioned weights it will also be necessary, as mentioned above, to use the very best material, workmanship, and heat treatment.
Complete detail and assembly drawings, as well as parts list and material specifications, can be completed at the Packard factory under our direction in less than four weeks. We believe that a sample motor can also be completed in approximately six weeks if money is used without stint. As soon as the drawings, specifications, and sample motor have been finished, complete information would, of course, be available so that any high-grade manufacturer could either make parts for this motor or manufacture it complete.
In laying down this design we have had in mind the extreme importance of interchangeability, as a well-laid, comprehensive programme which has for its base interchangeability of important parts, such as cylinders, will speed output and reduce ultimate cost to an astonishing extent. Europe is suffering right now from lack of uniformity of design, but it is too late for them to change their plan. We, however, can take a leaf out of their book and start right.
In the design which we have laid down, the cylinder, for instance, can be used to make four, six, eight, and twelve cylinder motors. As this is the most intricate part to make, immense facilities could be provided to produce them in large quantities for the use of many concerns who could manufacture the balance of the motor. Nearly all small parts and numerous largeand important ones would also be interchangeable. This would not only speed up production but would be of the utmost importance in connection with repairs and replacements. A full line of motors made according to this plan would line up about as follows:
Respectfully submitted,
(Signed)J. G. Vincent.
(Signed)E. J. Hall.
On June 4 Hall and Vincent finished a layout of an 8-cylinder engine, and presented the drawings and received an order to build ten sample engines, and on June 8 the Packard Company arranged for pattern-making, production work, etc.
This motor after intensive work on detail drawings was put into preliminary production. The first one was delivered to Washington, July 3, 1917. In the making of the sample engine Mr. Vincent’s company placed its factory organization at the disposal of the government, and through Mr. Vincent’s untiring efforts and enthusiasm the first motor was completed within the sixty days.
The other companies which aided in the work of building this motor were:
The General Aluminum and Brass Manufacturing Company of Detroit made bronze-backed, babbitt-lined bearings and aluminum castings.
The Cadillac Motor Car Company of Detroit made the connecting-rods, connecting upper-end bushings, connecting-rod bolts, and rocker-arm assemblies. The Cadillac Company had perfected the design of connecting-rods of the forked or straddle type, and had been using them for several years in their 8-cylinder engines.
The Parke Drop Forge Company of Cleveland made the crank-shaft forgings. These forgings completely heat-treated were produced in three days, simply because Mr. Hall gave them permission to dig out the Hall-Scott dies which were used in making the first Liberty crank-shaft forgings.
Hall-Scott Motor Car Company of San Francisco supplied all the bevel-gears out of its stock for the standardized line of Hall-Scott 4, 6, 8, and 12 cylinder aeroplane engines.
The L. O. Gordon Company of Muskegon made the cam-shafts.
The Hess-Bright Manufacturing Company of Philadelphia made the ball-bearings.
The Burd High Compression Ring Company of Rockford, Ill., supplied the piston-rings out of stock made up for the Hall-Scott line of standardized aeroplane engines, for which it had perfected a piston-ring.
The Aluminum Castings Company of Cleveland supplied the die-cast alloy pistons, and machined them up to grinding, as they had been engaged in making them for several years for the Hall-Scott line of standardized aviation engines.
The Rich Tool Company made the valves.