History Behind The Card: Maxim, 1890
Name: Sir Hiram Stevens Maxim, 1840 – 1916, Sangerville, Maine, United States of America
Sir Hiram Maxim is perhaps better known for his invention the Maxim Gun – the first portable, fully automatic machine gun – than he is for his aviation work – and despite what he accomplished, Wills’s card #30 states that by 1910, his contributions to aviation done in 1890 are almost forgotten. It is only somewhat correct. Wills’s remembered, many writers and aviators remembered, and this blog writer learned…
The back of the card (see below) erroneously states that he began his experiments in 1899—while the year 1890 is correct, which is why the card IS called Maxim, 1890.
For the record, I have a copy of a 1892 Cosmopolitan article (unlike the current style of that same name, Cosmo back then published articles on science as well as fiction). You can read the entire document written by Hiram Maxim HERE.
He began work in 1890 and completed one year later a 44.2-meter (145-feet) long vehicle with a wingspan of 33.53-meters (110-feet). Weighing a total of 3,556.16-kilograms (3.5-tons), the craft was powered by a pair of naptha fuel-powered steam engines that provided 180-horsepower each and turned a total of two pusher propellers of 5.33-meters (17.5-feet) in diameter.
This was his Maxim Bi-Plane… but… it wasn’t really meant to fly… at least not yet… it was his experimental air craft that he hoped would eventually lead to flight.
The plane was actually part of a larger structure that Maxim would use to tie down the plane in an effort to see if he could develop enough engine thrust to allow his plane to fly.
As for the structure of the ‘Maxim Bi-Plane Test-Rig’, on its lowest part it held a deck for the crew to stand, as well, it housed the boiler, steering wheel and tanks for water and gasoline. The two engines were placed 3.05-meters (10-feet) above the deck.
As per the Wills’s Card #30, there are five pairs of wings on the plane, but three of those wings are not always used—and at the time of its third trial (see below), they were not being utilized.
Both forward and aft of these wings are two steering planes that are connected by wire to a drum on the deck. By turning the drum, the steering planes can be adjusted up or down to direct the craft on an even path.
Since the ‘Maxim Bi-Plane Test-Rig’ was built solely as a test vehicle, it was held to a double set of rail track—one below and one above its running wheels—to prevent it from rising more than a couple of feet by a series of lifting and control surfaces (outriggers underneath and wooden safety rails overhead).
The safety track was made of squared pine logs 7.62-centimeters (3-inches) x 22.86-centimeters (9-inches) placed 60.96-centimeters (24-inches) above the steel way in a 9.14-meter (30-foot) gauge. Four other wheels were placed to the craft on outriggers and fitted to allow some lift.
During tests in 1894, the plane rode on 548.64-meters (1,800-feet) of rail. On the first trial, there was a 10.55-kilogram-force per square centimeter (150-pound-force per square inch) of steam pressure with no evidence of it leaving the steel track.
The second run utilized a 16.17-kilogram-force per square centimeter (230-pound-force per square inch) of steam pressure with a maximum of three outrigger wheels engaged simultaneously, but again there was no lift thanks to the steel rails.
On July 31, 1894 and fitted with a dynamometer, the ‘Maxim Bi-Plane Test-Rig’ had its engines and boilers with 272.16-kilograms (600-pounds) of water delivering a 21.8-kilogram-force per square centimeter (310-pound-force per square inch) of steam pressure and showed a total thrust of 2,164-pounds (981.6 kilograms). Satisfied, Maxim and three crew members sat about the craft and tried for a trial in motion.
Maxim describes the test: “The enormous screw-thrust started the engine so quickly that it nearly threw the engineers off their feet, and the machine bounded over the track at a great rate. Upon noticing a slight diminution in the steam pressure, I turned on more gas, when almost instantly the steam commenced to blow a steady blast from the small safety valve, showing that the pressure was at least 320 lbs. in the pipes supplying the engines with steam. Before starting on this run, the wheels that were to engage the upper track were painted, and it was the duty of one of my assistants to observe these wheels during the run, while another assistant watched the pressure gauges and dynagraphs. The first part of the track was up a slight incline, but the machine was lifted clear of the lower rails and all of the top wheels were fully engaged on the upper track when about 600 feet (91.44-meters) had been covered. The speed rapidly increased, and when 900 feet (274.32-meters) had been covered, one of the rear axle trees, which were of two-inch steel tubing, doubled up and set the rear end of the machine completely free. The pencils ran completely across the cylinders of the dynagraphs and caught on the underneath end. The rear end of the machine being set free, raised considerably above the track and swayed. At about 1,000 feet, the left forward wheel also got clear of the upper track, and shortly afterwards the right forward wheel tore up about 100 feet of the upper track. Steam was at once shut off and the machine sank directly to the earth, embedding the wheels in the soft turf without leaving any other marks, showing most conclusively that the machine was completely suspended in the air before it settled to the earth. In this accident, one of the pine timbers forming the upper track went completely through the lower framework of the machine and broke a number of the tubes, but no damage was done to the machinery except a slight injury to one of the screws.”
Maxim determined that when the plane exceeded 67.59-kilometers per hour (42-miles per hour), the whole structure lifted up into the air generating what was believed to be 4,535.92-kilograms (10,000-pounds) of lifting force which lifted it upwards with such force that it broke free of the upper restraining track and flew for 60.96-meters (200-feet) at an altitude of 0.61-meters to 0.91-meters (2- or 3-feet) generated before crashing.
From the September 15, 1894 edition of Scientific American, there is a thorough description of the feed heater used on the ‘Maxim Bi-Plane Test-Rig’: “The feed heater is constructed of steel tubes three-sixteenths inch bore and one-twelfth inch thick; the water is pumped through it at a pressure 30 lb. higher than the pressure in the boiler, and is delivered through an injector-like nozzle into the top of the downcomer pipe. The incoming water delivers its surplus energy to the surrounding liquid, creating a rapid and powerful current in the pipe, and consequently maintaining an active circulation in the small tubes in which the steam is generated. The feed pumps are placed on the deck beneath the engines, and are of variable stroke, so as to be adapted to the needs of the boiler. As they work at high speed, the valves are of large diameter-larger than that of the plungers. Pounding is prevented by a rubber bag on the suction and spring pistons on the discharge. The total quantity of water in the boiler only amounts to 200 lb., so that it is necessary that the amount of feed should be accurately adjusted. There is a very ingenious water level indicator. A small pipe is led in a loop from front to back and from back to front of the furnace. It is then taken to the steam and water drum, and led backward and forward through that in the same way, below the water line. The whole is filled with water, and forms a closed circuit having two loops-one in the furnace and one in the water. Now, so long as the upper loop is in the water the pressure does not rise greatly beyond that in the boiler, because the heat taken up in the furnace is conveyed, by the circulation, to the water in the drum. But if the water level falls in the drum, then there is no outlet for the heat; the pressure, consequently, rises most rapidly, and shows itself on a gauge attached to the pipe. By this most ingenious device an open-faced pressure gauge is substituted for the usual gauge glasses. The weight of the boiler, with casing, feed water heater, dome, and uptake, is 904 lb.; with burner and water it is 1,200 lb. The heating surface is about 800 square feet, and the flame surface 30 square feet.
The fuel burned in the boiler is gasoline, of a specific gravity of 72 degrees Baume. It is carried in a copper vessel on deck, and is pumped through a vaporizer into the furnace. The pipe from the pump is led into a vessel having a large gasoline burner beneath it. In this vessel the spirit attains a pressure of 50 lb. on the square inch, and a corresponding temperature, in which condition it is, of course, highly inflammable. The gas which it gives off is conducted by a pipe, passing through the furnace, to a jet, like that of a Bunsen burner, at the front of the furnace, and in rushing through it, induces a powerful draught of air, with which it mixes. The combined charge passes through hollow fire bars, pierced on the upper surfaces with fine holes, and burns in 7,650 separate flames. The arrangement is so powerful that the pressure in the boiler can be raised from 100 lb. to 200 lb. in a minute. The air supply can be regulated at will, while the expenditure of gasoline automatically adapts itself to the needs of the boiler. The pressure of the gasoline vapor acts on a ]ever, which is balanced by a spring. If the feed is greater than the consumption, the pressure on the ]ever puts a pawl in gear with a ratchet wheel, and, through intermediate mechanism, works a block along a slotted arm to reduce the throw of the gasoline feed pumps. If the feed is too small, the opposite effect is produced, and the throw of the pump increased.
There are two screws, each driven by a separate compound engine, having cylinders 5.05 inches and 8 inches in diameter by 12 inches stroke. The steam is distributed by means of piston valves having 3 inches stroke, and operated by eccentrics. The exhaust steam is delivered into the air, but Mr. Maxim informs us that he used successfully an air condenser. This seems to be a necessity, because the supply of water would prove a serious load. Even to drive 100 horse power would require some 2,500 lb. of water per hour, which would be a considerable addition to a lengthy trip, especially if undertaken for warlike purposes in a hostile country.
To supplement, or replace, the safety valve, by-passes are provided so as to allow live steam to pass directly to the low pressure cylinders. Instead of blowing off into the air, the steam is blown past the high pressure cylinders, and the fall in pressure is made to do work on the exhaust from the high pressure cylinders, drawing the steam from the high pressure cylinders and driving it into the low pressure cylinders. The boiler will make more steam than the engines can take in the usual way.
The boiler pressure, when running, is 320 lb. per square inch, giving in the high pressure cylinder a differential pressure of 195 lb. and in the low pressure cylinder 125 lb. The cut-offs are respectively 0.75 and 0.625 of the strokes. In the high pressure cylinder there is a very large clearance, designed to prevent injury from water in case the machine should pitch. The actual horse power delivered to the screws is 363 when the engines are running at 375 revolutions per minute. Of this, we are informed by Mr. Maxim, 150 horse power are expended in slip, 133 horse power in actual lift on the aeroplanes, and 80 horse power in driving the machine, with its frames and wires, through the air. The thrust of the screws, when the machine is moored, is 2,100 lb., and when it is running it is 2,000 lb. We give these figures as they were supplied to us, omitting decimals. The total lift is something over 10,000 lb. at a speed of forty miles an hour and with the aeroplanes making an angle of about 7.25 degrees with the horizontal.”
So, was this the first heavier-than-air flight done some nine years before the Wright Brothers? No. The “flight” was more of an out-of-control craft disintegrating as it traveled kind of flight. And, a successful flight includes a successful landing.
While Maxim did not attempt to fly the craft again, it did show that if a lighter and more powerful engine could be created—and that was limited by the technology of the day—that a major factor limiting flight could be overcome.