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Shooting the Catapult
(See page 545, April, 1933, Proceedings)
Maurice Prendergast.—Lieutenant Miller will not be surprised to see me on jjls track again! After he had contributed Covered Wagons of the Sea” (November, ^1, Proceedings), I followed him up by ^riting “Wings and Wheels: Wood and Wire” for the February, 1932, number of 'Ms journal. My essay gave the history of 'he British aircraft carriers of 1914—24, aUd when writing it, I found it necessary '° include a footnote reference to the U. S. Navy experiments with the Chambers 'ype of catapult in 1914. When I wrote hat note, I had a hope, a very faint hope, hat it might prompt some American offiCer to write the history of the aircraft cata- jMit. Lieutenant Miller has fulfilled my h^Pe and has exceeded my anticipations. Mis article, “Shooting the Catapult,” not °% contains a most interesting collection M authenticated historical facts and dates; lt reveals, to me at least, if not to others, Much that was hitherto unknown. My ig- Uorance about the early history of the catapult is perhaps excusable, because Many of the U. S. Navy experiments were Made in 1914-17, and during that period he European press had little space for anythingbut war news.
First of all, let us turn to the Lake N;euka experiments, made in 1911-12 by lieutenant T. G. Ellyson, U. S. Navy.
leutenant Miller describes how a steel r°peway 250 feet long was erected. One ®nd of the cable was secured to a tripod h feet high, and the other end to a pile
submerged below the surface of the lake. The cable, he says, had a falling gradient of about 10 per cent. Down this taut wire Ellyson slithered his airplane with the engine running at full power, and after sliding down the cable for 150 feet, his craft gradually took the air. Such, says Lieutenant Miller, was “the first naval catapult.”
But was this device really a catapult at all? Surely a catapult is an engine which, by means of stored-up energy, slings some heavy missle into flight. The Romans and Carthaginians slung chunks of rock with their catapults, and we sling off aircraft with ours. Take any aircraft catapult and what do you find? That it contains or is attached to a power generator of some kind, and such generator is entirely separate and independent from the power unit built into the structure of the airplane that is to be launched. This power, external to the plane, is used for the slinging forward of a vehicle to which the aircraft is initially locked.
In the Ellyson ropeway there was no external impelling power and no traveling carriage whatever. The airplane was not made captive to the cable during its glissade down the ropeway. Ellyson’s machine did not even get the extra impetus that was provided by the haul of the descending weight in the Wright Brothers’ primitive launching apparatus. Ellyson’s ropeway, therefore, seems to have been no better and no worse than the rails, troughs, and platforms with falling gradients, such as were used in the early efforts to fly aircraft off from the decks of ships.
Describing the 1915 catapult trials in the armored cruiser North Carolina, Lieutenant Miller tells us that it was found necessary to improvise a crane for the lifting inboard of the aircraft. This, he says, was done by the insertion of a temporary boom into one of the 10-inch guns in the cruiser’s after turret. If the upper of the two illustrations facing page 545 of the April Proceedings is examined, there on the left-hand side will be seen the improvised “turret crane.” My own notes say that later the boom was fixed to the foot of the gun shield. .
The Engineer (London) published on March 17, 1916, a note and illustration of the North Carolina catapult experiments. Brief as the description was, I was greatly impressed with the possibilities of the device, and therefore I sought and obtained permission from The Engineer to republish its close-up illustration of the catapult in Fighting Ships, of which naval annual I was then the editor. The 1916 edition of Jane (p. 138a) displays this illustration, showing a Curtiss type of flying boat (apparently without pilot) at the moment of delivery from the catapult.
On page 553 Lieutenant Miller refers to the mounting of the first turntable catapult “on the quarter-deck of a battleship” in 1922, but unfortunately he does not give us the name of the battleship. I cannot make good this deficiency of an interesting historical fact. My own notes merely contain a rather dubious entry that “the first U.S. Navy turntable catapult was built at the Philadelphia Navy Yard in 1921.” I also have a jotting to the effect that the annual report of the Bureau of Construction and Repair for 1923 said that a new type of catapult had been begun for the battleship New Mexico, but this catapult had not been completed and tested by the time the report was completed. Was this the first powder-impulse
catapult, assigned in 1924 to the Mississippi instead of to the New Mexico? After this entry, I have the note (taken from a summer 1925 issue of the Italian Rivista Marittima): “December 14, 1924: Mississippi successfully shot off plane with new powder-impulse catapult.” Was this the date of the first successful shot wfith a powder catapult mounted in a U.S. warship?
As regards British experiments with catapults, little can be said as yet, because information on their history has not, so far as I am aware, been released up to the present. The British Navy did, however, have a “special airplane catapult vessel’ in 1917, the .S7mger,ofwhich an illustration appeared on page 129 of Fighting Ships> 1919 edition. When the press censorship was lifted at the end of the World War, the Daily Mirror (London) published on February 8,1919, a photograph of the Stinger's catapult at work, launching a large glider (without pilot) into flight. The SlingM was not much of a success. After the war she was sold out, and when last heard of she was doing duty as a mud mopper in Greek waters.
What was the first British warship to mount a catapult? From what Lieutenant Miller says on page 554, one might conclude it was the cruiser Vindictive in 1925. When the Admiralty chooses to make its records known, I think it will be found that British warships were at sea, testing experimental catapults, long before 1925. And I think it will be then discovered that the British Navy, at one time and another, has mounted a catapult in every type of combatant war vessel, that is, in a battleship, a battle cruiser, an aircraft carrier, a cruiser, a destroyer, and a submarine.
The submarine was, of course, the ill' fated M-2 to which Lieutenant Miller alludes in his article. He thinks that the M-2 had to be given a catapult because her small seaplane had not power enough to
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1933]
Discussions
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take off from the normal swells encountered in the open sea.” Perhaps I maybe Permitted to say a word or two about the M-2. She was originally designed and built as a submarine carrying a single 12-inch 8Ulb and her conversion into an aircraftcarrying vessel was no more than an im- Provization out of existing material. The ]^ea in altering her is said to have been making of practical investigation into be possibilities of large and fast fleet submarines carrying small scouting seaplanes. 1 was argued that big surface aircraft carriers of 20,000 tons and more, would be ^Uch too valuable and vulnerable to be ^Pread by themselves on any scouting llle far in advance of the battle fleet. Fast eet submarines could, however, be safely to advanced positions from which hey could send away their aerial scouts. 1 the enemy should appear, the submarines could dive, and when he had Passed by they could return to the surface and recover their seaplanes. Such diving farriers would not be forced to retreat on mir main body for support. If, on the °ther hand, the submarines were detected, attacked, and kept under, their aircraft ^uld fly back and obtain a perch on the *8 surface carriers in company with the battle fleet.
bn the first (1927-28) tests with the converted M-2, the seaplane was extracted r°m its hangar, its wings extended, and epgine warmed up. It was then put over the ®|de by means of a crane and took off from e surface in the usual way. The tests ere quite successful, but the delivery of e plane into flight took too much time, ccordingly, it was decided in October, 8, to equip the M-2 with a fixed-struc- Urp compressed-air catapult. Electric gme and lubricating oil heaters were ted in the hangar, so that whilst the subfine was cruising submerged and re- rnipg to the surface, the preliminary embarked airplane. As soon as the
submarine surfaced, the hangar door was dropped, the seaplane trundled out, its wings extended, and engine started up. It was then shot off, and the whole operation was carried out with remarkable quickness. The catapult was rather short in length and remarkably powerful—so powerful in fact that it gave the pilot and observer of the seaplane rather a severe shaking at the moment of release, but it delivered the plane cleanly, without wobble or drop, into the air. This catapult was mounted only a few feet above the surface of the sea, and was in fact almost awash when M-2 ran head-to-wind at full speed. A very powerful impulse had to be given, to make sure that the seaplane should not lose an inch of height after it was shot off. The catapult, being mounted on the fore deck, was immersed every time the submarine dived, but none the less, functioned well.
One of the most interesting of recent innovations in the British Navy, of which particulars have been published, has been the mounting of a twin-catapult system in the cruiser Exeter. The two catapults, of the Forbes’s patent telescopic type, are fixed structures placed between the second funnel and mainmast of the cruiser. When telescoped down to their shortest lengths, the catapults have (in plan) a V-shape, their forward ends angling outboard and forward at an angle of about 45° to port and starboard of the center line. For shooting off a plane, it is only necessary to run out the fore-and-aft extensions of one catapult forming a side of the V, according to whether it has been decided to launch an airplane to port or starboard of the cruiser.
There was one point not touched on by Lieutenant Miller in his very interesting article. It was the positions in which aircraft catapults have been mounted. What is the most practical and serviceable location for the machine that slams the airplane into flight?