CHAPTER III
THE CURTISS MOTOR AND FACTORY
The history of the Curtiss motor goes back to the early days at Hammondsport; it was the keynote of the development of the motorcycle, the airship, the aeroplane, and the hydro. From a crude single-cylinder engine used on an experimental bicycle, the motor has developed to an eight-cylinder engine giving over eighty horsepower, on which the reliability of the Curtiss aeroplane is dependent. Indeed, flight itself, in the history of the world, was delayed until the development of the gas engine made it possible to get a power that was applicable for this purpose, and one that was, at the same time, light enough.
To describe the motor intelligibly to one who has had no acquaintanceship whatever with gas engines would require many chapters, but to those who have ever examined automobile, marine, or other motors, the following technical data will give an idea of the distinctive feature of this aeroplane motor.
MOTOR DESIGN AND MATERIAL.
Crankshaft:
The crankshaft is supported in five bearings of more than ample size. It is extremely difficult, if not impossible, to design a shaft which will be light enough for aeronautical purposes, and still be sufficiently rigid without a special support. The propeller end of the shaft is supported in two places eleven and three-eighth inches apart, at one end in a plain bearing two and seven-sixteenth inches long and at the other in a combined radial and thrust ball bearing of ample size. This construction is stronger than is the case where the propeller is mounted immediately behind the last main bearing proper or even in some cases carried at a distance of several inches from the bearing without support. Any lack of mechanical or thrust balance is multiplied and transmitted directly to the last crank throw, the tremendous racking and twisting strain thus occasioned causing ultimate failure.
The crankshaft is made of imported Chrome-Nickel steel, properly heat treated. This steel, particularly after heat treatment, has an enormous tensile strength combined with a very high elastic limit and great resistance to fatigue and crystallisation.
Connecting Rods:
The connecting rods are machined from a solid Chrome-Nickel steel forging, heat treated. The body of the rod is tubular, which cross section gives a maximum strength with minimum weight. Rough forging weighs five pounds; finished weight one pound eight ounces.
Piston:
The piston is long enough to give sufficient bearing surface to sustain the side thrust from the connecting rod and at the same time weighs but two and one-half pounds. The domed head, with properly placed ribs, assures strength. The piston pin bearing is seven-eighth inches diameter by two and three-fourth inches long. Reversing common practice, the pin turns in the piston instead of the rod end, as considerable gain in bearing surface is thus made.
Engineers will appreciate that with a combined piston and rod weight of four and one-half pounds, the strains from twenty-two hundred reversals of motion per minute at normal speed are very slight.
It has three rings together with fourteen oil grooves aiding the rings in retaining compression and assisting the oiling. All pistons are rough turned and then thoroughly annealed before grinding, to insure against warping in service.
The piston rings are of clean springy iron, ground all over. As a ring must be tight on the sides as well as where it comes in contact with the cylinder, there must not be a variation in width of over a quarter thousandth of an inch.
Cylinder:
The cylinder is symmetrical in design, insuring even expansion without distortion.
Valve-in-the-head construction gives an efficient shape of combustion chamber; the compact charge fired in the centre giving quick, complete combustion, and the large valves give free ingress and egress for the gases.
The water jacket is brazed to the cylinder-casting autogenously, the metal being a composition of nickel and copper known as "Monel" metal, which is proof against corrosion.
Cylinders are bored, ground and finished by lapping, to get a glass smooth surface.
Water Circulation:
The water circulation is so carried out that all cylinders are cooled equally, the water pump being divided by a partition which passes water in equal quantities to each set of four, thus avoiding any possibility of a steam-trap on one side causing all the water to pass through the other side. The pump is driven from the crankshaft by a floating joint. The pump shaft is made of a carbon spindle steel.
A portion of the hot water is returned through the carburetor water jacket, which is essential with present day gasoline, particularly in cold weather or high altitudes.
Lubrication:
The lubrication is a combined circulating and splash oiling system. A gear driven oil pump submerged in the oil pan forces a constant stream of filtered oil through the hollow cam shaft bearing, thence to each individual cam shaft bearing, thence to the main crankshaft bearings whence it is forced through the hollow crankshaft and cheeks to the crank pins, the surplus replenishing the oil pan into which the rods dip, thus oiling the cylinder walls by splash and also filling oil pockets on each main bearing, as an additional insurance against their running dry.
The pump is driven off a bevel gear integral with the crankshaft and is of the gear type, being without valves or moving parts other than two simple spur gears. It is entirely enclosed in a fine mesh screen through which the oil must pass to reach the pump.
Valves:
The valves have cast-iron heads reinforced with a perforated steel disc embedded in the cast iron, the whole being electrically welded to a carbon steel stem. The cam shaft is hardened and ground and cams formed integral with the shaft. The cam contour is also ground, the valve timing being exactly the same in each cylinder.
[Illustration: CURTISS MOTORS]
(A) The first Curtiss aerial motor; used In Baldwin dirigible. (B) Motor used in both the "White Wing" and "Red Wing." (C) Motor of 1912.
[Illustration: AT THE AEROPLANE FACTORY, HAMMONDSPORT]
(A) Testing aeroplanes. Gravel on reversed planes tests strength; scale shows wire-strain. (B) Assembly room of factory.
Castings:
The majority of non-moving parts, including the crank case, are cast of special aluminum alloys. Recent laboratory tests have shown tensile strengths of as high as fifty thousand, five hundred pounds per square inch.
Weight:
The weight of model "A" motor alone is two hundred eighty-five pounds–three and eight-tenth pounds per horse-power. The weight of power plant including propeller, radiator, and necessary connections is three hundred forty-seven pounds.
Note that the forty horse-power cylinder motor weighs one hundred seventy-five pounds and gives a thrust of three hundred ten pounds when equipped with a seven foot diameter by six foot pitch propeller turning at nine hundred revolutions per minute. The pitch speed of the propeller at this rate is in excess of a mile a minute.
Gas-Consumption:
The consumption of gas is three-fourths pint per horse-power per hour. The engine can be throttled and consumption reduced in nearly direct ratio to the horse-power developed.
Consumption on full throttle per hour is seven and one-fourth gallons gasoline and one gallon of oil. The oil capacity of the small pan is four gallons; of the large pan, six gallons.
Testing and Power:
Each engine is given an extended run with propeller load. After giving the required standing thrust at the proper speed, the engine is completely torn down for inspection and carbon removed. After assembling, it is given a second test on a water dynamometer, which gives the horse-power developed.
Miscellaneous:
Few people realise that the aeronautical motor is subjected to usage equalled by few internal combustion engines. The average car engine is seldom run on full throttle for extended periods. The marine engine is ordinarily a very heavy, slow speed machine. The aeronautical motor, to run at the high speeds under full load demanded to-day, must of necessity be designed with this fact in mind, and particular attention paid to numerous weaknesses apt to develop under this treatment.
Adding to the above the necessity for minimum weight while still retaining a sufficient factor of safety in all parts, it is evident that an aeronautical motor must be designed as such and not be a modified edition of an automobile engine with a few pounds removed here and there.
PARTS OF CURTISS MOTOR–A COMPLETE LIST.
1-5, Breather Pipe Cap Screw & Flange, Collar, Cap & Clip; 6, Ball Bearing (Radial); 7-8, Crank Case, Upper Half & Lower Half; 9-10, Crank Case Bolt, Small & Large; 11, Crank Shaft.
12, Cam Shaft; 13-15, Cam Shaft Bearing, Front, Centre, & Rear; 16, Cam Shaft Bearing Sleeve, Rear; 17-18, Cam Shaft Gear & Retaining Screw; 19-20, Cam Shaft Bearing Clamping Screw, Centre, & Retaining Screw; 21, Cam Follower Guide Stud; 22, Cam Follower Guide Screw; 23, Cam Follower; 24-25, Cam Follower Guide & Plug.
26, Cylinder; 27, Cylinder Tie Down Yoke; 28-29, Cylinder Stud, Long & Short; 30, Cylinder Stud Nut; 31-32, Connecting Rod & Bolt; 33, Connecting Rod Bolt Nut; 34, Compression Tee for Oil Pipe; 35, Compression Coupling Sleeve; 36-37, Cable Holder & Screw; 38-39, Cable Tube & End; 40-41, Cable Tube Clip & Screw; 42, Carburetor Water Pipe Clip.
43, Exhaust & Inlet Valve; 44, Exhaust Valve Spring; 45, Felt Oil Retainer for Rear Thrust Bearing; 46, Felt Oil Retainer for Magneto Gear; 47, Gasket for Intake Manifold; 48-49, Gear Case Cover & Screw; 50, Gear Cover Packing Nut; 51, Half Time Gear; 52, Intake Pipe Elbow; 53, Intake Pipe with 2 Union Nuts; 54-56, Intake Pipe Y & Support Base & Cap; 57-62, Intake Manifold, & Bolt, Bolt Nut, Cap Screw, Union Nut, & Elbow Cap Screw; 63, Intake Valve Spring; 64, Magneto Bracket; 65, Magneto Gear; 66-67, Magneto Bracket Cap Screw, Large & Small; 68, Magneto Base Cap Screw.
69, Main Bearing Stud Nut; 70, Main Bearing Stud, New; 71-73, Main Bearing Cap, Front, Centre & Rear; 74-75, Main Bearing Babbitt, Front, Upper, & Lower; 76-77, Main Bearing Babbitt, Centre, Upper & Lower; 78-79, Main Bearing Babbitt, Rear, Upper, & Lower; 80, Main Bearing Babbitt Clamping Screw; 81, Main Bearing Liner, Front & Rear; 82, Main Bearing Liner Centre; 83, Main Bearing Liners.
84, Nipple for Oil Pump; 85-86, Oil Pump & Leader Gear Shaft; 87-94, Oil Pump Follower Gear, Cover, Drive Pinion, Screen, Support Bolt, Cover Screw, Follower Gear Bushing, & Shaft Bushing; 95, Oil Pipe for Pump; 96-97, Oil Pump Compression Coupling & Nut; 98-99, Oil Sight, Base & Glass; 100-101, Oil Sight Glass Guard & Cap; 102, Oil Splash Pan; 103, Oil Bleeder Pipe; 104, Oil Bleeder Pet Cock.
105-107, Piston, Pin & Ring; 108-109, Pump Packing Nut, Large & Small; 110-114, Push Rod, End Bearing Pin Lock Screw, Spring, Spring Support, Forked End, & End Bearing Pin; 115, Propeller Bolt; 116-121, Rocker Arm, Support, Bearing Pin Set Screw, Tappet Screw, Support Cap Screw, & Bearing Pin; 122-124, Spark Plug (Herz) Gasket,--& Wrench; 125-129, Thrust Bearing, End Clamp, Lock Ring, End Clamp Screw, End Clamp Bolt, End Thread Bolt Nut; 130, Valve Push Rod; 131, Valve Stem Washer; 132, Valve Stem Lock Washer.
133-135, Water Jacket, Inlet Nut, & Inlet; 136, Water Pump; 137-140, Water Pump Shaft, Support Stud, Impeller, & Driver; 141, Water Pump Friction Sleeve; 142-143, Water Pump Friction Washer, Front & Rear; 144-145, Water Pump Bushing, Front & Rear; 146, Water Pump Gasket; 147-149, Water Pump Universal Joint Member, Male, Female, & Spring; 150-151, Water Pipe, Right Hand, Bottom, & Left Hand, Bottom; 152, Water Pipe Outlet Elbow; 153-156, Water Outlet Top Pipes for Cylinders.
A VISIT TO THE FACTORY
A visit to the Curtiss factory is of interest to any one interested in machinery and there you will see the latest machines of all types, from powerful milling machines to a delicate modern "Printograph" that is almost human in its manner of getting out letters and printing, for it is a cross between a printing press and a typewriter. Another unique machine is one that carves out propellers from a laminated block of wood. One arm of this machine runs over a model, and the other, about two feet away, arranged to move exactly with it, and provided with a tool of cutting edge, forms the propeller blade with absolute accuracy, out of a block of wood placed parallel to the model. The cutting tool follows all the complex changes in the surface of the wooden propeller with the greatest ease and rapidity.
The brazing room, where the oxy-hydrogen torch is used to braze metal parts together, and the room where they weld the water jackets on to the cylinders, are places of special interest; the nickel plating room, japanning room, and the room where painting and drying are done, almost complete the tour of the various departments, but there still remain the wood-working shop, boat shop, assembling rooms, where the aeroplanes are put together and completely set up, and the motor testing room, where motors are run for whole days, ten hours at a time, driving an air propeller and showing on scales the amount of thrust given at all times.
Here you may also see a machine to make "brake tests" of the motors, by which is told how much horse-power the motors give. This machine consists of a large drum with a brake fixed against it and cooled by water so it will not get too hot. This brake absorbs the energy of the motor, which is measured by an arrangement of scales and lever arms.
There is a tremendous racket when the big motors are running at full speed in this small room, and the hillside rings with the roar of their fiery exhaust.
In the laboratory of the factory, where the designs and drawings are made, there is one of the most interesting pieces of apparatus in the whole plant. This is a "wind tunnel," where models of aeroplanes are tested and where experiments are tried to see what occurs in the stream of air. Here tests are made which assist in determining what the best form and shape of objects such as upright posts and exposed parts shall be and where a measure of their relative resistances may be made. The tunnel itself consists of a square box with a propeller or fan mounted at one end to create a draft or current of air which passes through a screen to cause it to assume uniform motion. There is a window in the tunnel through which the observer can see the action of the objects to be tested. Varying the speed of the fan varies the speed of the air current and its pressure, and in this manner the stream-lines of air under the varying conditions and the effect upon models of different forms and shapes may be studied to enable refinements to be made in the aeroplane's construction.
Down on the shore of Lake Keuka, about a half mile from the factory, are the aeroplane sheds and the flying field. Here is where the aviation school is situated, and where flyers are made. Over the smooth field, the pupils start with the four-cylinder "grass cutters," or machines hobbled so they cannot get but a little way off the ground. They hop, hop, hop, almost all day long, one after the other taking regular turns, and now and again varying the monotony by being called away by the flying instructor to take a real flight in the hydroaeroplane out over the lake to get accustomed to the upper air, and to the high speed of the big machine.
Later in his course of instruction, the student takes out an eight-cylinder machine and flies around in circles over the field until he is able to take the test for his Aero Club of America License, which requires him to make two series of figure eights around two pylons fifteen hundred feet apart, landing each time within one hundred and fifty feet of a mark and rising to an altitude greater than two hundred feet.
This is the goal of the novice, and after his test, the student is ready to fly as far and as fast as he likes. He has become the complete airman.
[1] It is interesting to note that Lieutenant Frank P. Lahm, the sole American entrant for the Gordon Bennett Balloon Cup in 1906; Mr. Edgar Mix, the only representative of America in the balloon contest in 1909, and Mr. Charles Weymann, the only entrant from America in the Gordon Bennett Aviation Cup race of 1911, held in England, all won.
[2] Tod Shriver, or "Slim" as he was known to all American aviators because he was very tall and slender, went to Rheims as a mechanic before taking up flying himself. He was successful as an aviator and accompanied Captain Thomas Baldwin to the Orient in the spring and summer of 1911. This trip created great excitement among the Chinese, who had never seen the "foreign devils" fly before. Captain Baldwin tells a story of the crowd that witnessed the flights in Tokyo, Japan, which he describes as numbering seven hundred thousand persons! In proof of this he states that advices received from Japan in the spring of 1912 report that the crowd had not entirely dispersed even at that time! "Tod" Shriver flew in many places in the United States and in the winter of 1911 met his death in Puerto Rico. He fell while flying at Ponce. His death was a shock to his many friends. [Note by AUGUSTUS POST.]
[3] NOTE BY AUGUSTUS POST While flying in the Chicago meet we had four machines in the air at once. I was a novice at flying then but entered the air while the other fellows were flying around. Circling the track I was just passing the grand stand when Willard swooped down in front of me having passed right over my head. I clung on to the steering post and held the wheel as firmly as I could while to my great consternation the machine rocked and swayed fearfully in the back draft from Willard's propeller. He kept doing the Dutch Roll and the Coney Island Dip right in front of me, which made it all the worse, as the wash of the propeller wake would strike above and below my machine as he pitched up and down in front of me. I stood it as best I could, hardly daring to breathe but holding my course and balancing with all my might, until Willard turned off, and then after a bit I made a good landing. When Willard came down he rushed up to me and grabbed me by the hand and said, "Oh, Post! will you ever forgive me for that? I ought to have known better than to back-wash you but you know I thought you were Ely, and I wanted to scare him!"–A. P.
[4] NOTE BY AUGUSTUS POST An interesting story is told of how the hydroaeroplane came to be invented. During the period when he was planning a new series of experiments, Mr. Curtiss, accompanied by Mrs. Curtiss, attended a New York theatre in which there was being presented a play much talked about just then. The curtain went up on the first act, and the noted aviator was apparently enjoying the show when, just as the scene was developing one of its most interesting climaxes, he turned to Mrs. Curtiss and said: "I've got it." On the theatre program he had sketched what ultimately became the design of the hydroaeroplane. This is like a time when Mr. Curtiss was standing one day by the side of one of his motorcycles talking with a customer. He kept turning one of the grips of the handle-bar with his fingers while talking and after finishing the conversation went into his office and developed the idea of a handle-control which had come to him while apparently absorbed in conversation.–A. P.
[5] The fame of the hydroaeroplane has reached the Orient and a demonstration was recently given at Tokyo, Japan, for the benefit of the Japanese Army and Navy officials by Mr. W. B. Atwater, of New York. Mr. and Mrs. Atwater are on a tour of the world, carrying with them two Curtiss hydroaeroplanes and giving demonstrations of a practical character before the military authorities of all the countries en route. On Saturday, May 11th, 1912, he made three flights at Tokyo, the first hydro flights ever seen in the Orient. There was a great gathering of military men to witness the flights, among them Prince Kwacho, representing the Japanese Imperial Family; Admiral Saito, Minister of the Imperial Navy, and Vice-Admiral Uryu. According to the statement of the Japan Advertiser the Japanese Navy has followed the example of Russia, and forwarded to America an order for four Curtiss hydroaeroplanes.–A. P.
[6] The first start from a roof-top was made on June 12, 1912, when Silas Christoferson in a Curtiss biplane rose from a platform built on the roof of the Hotel Multnomah, Portland, Ore., and flew safely away.–AUGUSTUS POST.
[7] A very important service was rendered only a short time ago by the hydroaeroplane which might easily have served to save a human life if the accident had been more serious than it actually was. Mr. Hugh Robinson the instructor of the Curtiss hydroaeroplane school was having Sunday dinner at the hotel in Hammondsport, where Dr. P. L. Alden, one of the well-known physicians of that place, was also eating dinner, when the doctor received a telephone message that Mr. Edwin Petrie's little son had fallen from the steps of the Urbana Wine Company at Urbana, five miles down the lake, and had a compound fracture of his thigh with a serious hemorrhage. It was a very serious injury and the little fellow was in intense pain, and Mr. Petrie asked the doctor to come as quickly as he possibly could. Dr. Alden realised the urgency of the situation and knew that delay might mean serious results from hemorrhage, so he went immediately over to Mr. Robinson and asked if he would take him across the lake in the hydroaeroplane right away. Mr. Robinson said, "I will be ready in five minutes; just as soon as you can get over to the field." Dr. Alden got his bandages and instruments and hurried down to the shed where Mr. Robinson had already gotten out the hydro; he jumped in and they were off without a moment's delay. They covered the five miles in five minutes, at times running on the surface of the lake because the wind was blowing so strong; as they ran up on the beach the doctor jumped out and hastened to his patient. The boy was so much interested in the fact that he was the first patient to be treated by a hydroaeroplane doctor, and so fascinated at hearing Dr. Alden tell about the trip, that he forgot for the moment the seriousness of his condition and allowed the doctor to reduce the fracture without an anesthetic. When all that could be done just then had been done, Dr. Alden and Mr. Robinson returned in the hydroaeroplane as rapidly as they had come on their errand of humanity, and at last accounts young Mr. Petrie was getting well as fast as he could so he could have a ride in the hydroaeroplane himself!–AUGUSTUS POST.
[8] In July, 1912, Captain Beck was granted by the War Department the title of "Military Aviator"; the first time that any American has been given this title, which implies finished skill in both aviation and military tactics, and for which all the army aviators are to qualify.–AUGUSTUS POST.
[9] Mr. Post is not only intimately connected with the development of the aeroplane but also one of the most capable practical balloon-pilots in the world. Mr. Post accompanied Mr. Allan R. Hawley in October, 1910, when the balloon "America II," representing the United States, broke the world's competition record and won the Gordon Bennett balloon cup by sailing one thousand one hundred seventy-two miles from St. Louis to Lake Tschotogama, in the wilds of Quebec. The trip took forty-six hours. This record still stands as American distance record. Mr. Post also holds, with Mr. Clifford B. Harmon, the American endurance record of forty-eight hours, twenty-six minutes.–THE PUBLISHERS.
[10] Ralph Johnstone said in a conversation about experiences while learning to fly, "I learned to fly all right but one day when I was up in the air pretty high I seemed to forget all about it and how to operate the controls. I tried them and tested how they worked and it seemed to me that I learned all over again, but it did seem funny to me for just a few minutes." Geo. W. Beatty said, "When I was flying at Chicago, in the contest for duration, when the weather was calm, and I had nothing else to do but sit and think while the machine flew on, round and round, lap after lap, I would look out at a wire and watch it as it vibrated and wonder if it was possible for it to break, while I realised that I could not get out to fix it. This worried me more than flying in a high wind. It seems more natural for me to fly than not to. I have been in the air on an average of two hours every day for over a year."
[11] To indicate the exact technical knowledge required in building an aeroplane, a matter quite apart from the obvious dash and daring of the aviator, nothing seems more adequate than to include the list of aeroplane and motor parts.–THE PUBLISHERS.