Flight, May 1923

THE MARTIN M.S.1 NAVY SHIPBOARD SCOUT

   SOME successful tests were recently completed on Lake Erie with a new type of seaplane designed by the United States Navy and developed by the Glenn L. Martin Co. of Cleveland., It is known as the M.S.1, and is a very small tractor biplane seaplane for shipboard use. This machine is of all-metal construction except for the covering. It has a span of 18 ft., is 17 ft. 6 ins. long and 7 ft. 6 ins. high from the water-line, and its actual weight is less than 650 lbs. Notwithstanding its small size, it handles and manoeuvres remarkably well, and has a performance comparing very favourably with larger, higher powered craft. Actual performance figures are not available, but it is stated that, considering it is a seaplane with but a 60 h.p. engine, its speed is quite high.
   The power plant is a Lawrence L.4S three-cylinder, 60 h.p., air-cooled engine driving a 6 ft. 6 ins. air-screw. The engine is mounted on a vertical bulkhead at the forward end of the rectangular section fuselage, which is built-up entirely of steel tubing. The method of assembling the fuselage is of interest. It is built up in a jig, the various members being held in position by special clamps until all the fittings have been made. This results in a perfectly rigid structure, which requires practically no truing up. The fittings themselves are quite simple, and are attached in place by rosette welding. This method of welding, which was developed at the Martin factory, consists of drilling holes through both the main members and the fittings and torch-welding the material around the radius of the holes. Tests on this type of fitting have shown exceptional strength for a minimum of weight.
   The pilot's cockpit, situated at the trailing edges of the wings, is roomy, and all the controls and instruments are readily accessible. Beyond radio equipment no military load is carried. The tail surfaces and wings are built up entirely of duralumin, channel sections being used largely for the bracing; while the ribs are stamped out of the material in one piece. Two-inch tubular duralumin is used for the wing spars, and the leading and trailing edges are of channel duralumin riveted to the ribs. The wings, tail surfaces and also the fuselage are covered with fabric.
   Interplane bracing is by one set of N-struts on each side, the flying and landing loads being taken by diagonal struts between the floats and the outside of the lower wing. The lower wings are attached to the lower longerons of the fuselage, while the upper wings are attached at the centre to a short cabane. The machine is easily dismantled or assembled, and stowed away in a small space.
   The construction of the floats is somewhat unusual. These are entirely of duralumin, the structure being built up of channel-section bracing with watertight bulkheads. The float fittings for the brace struts to the plane structure are aluminium-alloy castings. Sheet duralumin is used for the float covering; all joints are made watertight by the use of wicking, impregnated with marine glue, placed in the joints at the time of riveting. All interplane and float struts are streamlined with sheet duralumin. The petrol tank is of welded aluminium, and has a capacity of 12 gals. - or sufficient for a flight of two hours at full speed.

Flight, February 1927

AN AMERICAN SUBMARINE SEAPLANE-CARRIER

   IN the development of Naval aeronautics the problem of producing aircraft capable of storage in very confined spaces, to enable them to be carried for effective purposes to sea, has been widely considered by the leading Powers. In the case of aircraft carriers they have been successful; but the adaptability of aircraft for attachment and operation with submarines has presented many difficulties. In FLIGHT, June 14, 1923, we described in detail a German Seaplane, the Caspar U.I, which was specially designed, in spite of the restrictions enforced on Germany by the Allies, for submarine work.
   Recently the U.S. Bureau of Aeronautics pursuing their research into the question, produced a very promising scheme. A tube, into which a scout seaplane is neatly stowed away in parts, is lashed to the submarine - this tubular hangar in no way hindering the submarine in its movements at sea or diving. The scout, it is claimed, can be assembled, complete with floats, in five minutes, so that a reconnaissance flight can be carried out at a moment's notice. It is equipped with wireless, and can thus keep in touch with the submarine.
   If this scheme becomes practicable it will add considerably to the effectiveness of submarines both offensively and defensively. With their speed these scouts would sweep the scene of operations to report the presence of the enemy and guide the direction, observing meanwhile for the approach of aerial foes. Incidentally a much desired zest will be added to the monotony of sea patrol for flying-boats and seaplanes. The enemy may be more elusive than ever but it is quite possible that the submarine can put up aerial resistance. There may be decoy tactics to be aware of. From safe altitudes a scout may watch a seaplane sweeping after a submarine that is intentionally tearing along the surface in sight, and with all attention thus focussed the scout may descend unseen and attack the other seaplane. The S-1, which the Americans produced for this submarine work is a small single-seater tractor-fuselage biplane, with twin-floats, having a wing span of about 18 ft. It is largely of metal construction, the fuselage being built of welded steel tubing and the wings and tail unit of channel-section duralumin sheet. The tubular spars and ribs are one-piece stampings of the same material, and the covering for fuselage and wings is fabric. The floats are also of duralumin. There is single-bay wing bracing, by a set of N struts at each side. Quick assembly and dismantling have been essentially embodied in its design and when stowed away in its tube, as seen in the accompanying illustration, it occupies a remarkably small space.
   Fitted with a 60 h.p. Wright 3-cylinder radial engine, the S-1 has a speed range of 50-100 m.p.h. and a radius of action of 200 miles - although 500 miles has been claimed for it in some reports.
   It may be of interest to note in conclusion that France is carrying out experiments on exactly similar lines as above. The Besson company have just produced a small 2-seater twin-float mono-seaplane, fitted with a Salmson 120-h.p. engine, which can be packed away within its tubular hangar carried on the submarine's deck. This Besson seaplane was recently flown from the Melun works to Suresnes, prior to being sent to Brest where it is to be put into service with a submarine flotilla.