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A Novel Undercarriage

A Novel Undercarriage October, 1934 AIRCRAFT ENGINEERING 277 Th e Experimental Messier Monoplane with Tandem Whee l Retractable Landing Gear H E Société Francaise de Matériel d'Aviation, who manufacture aircraft accessories, such as brakes and oleo- pneumatic shock-absorbers, invented by the founder, the late Georges Messier, have recently built an experimental low wing monoplane fitted with an interesting tandem wheel retract­ able undercarriage embodying some of his ideas. The following description is illustrated mainly from various paten t specifications. The tande m wheel undercarriage is, of course, not new to modern aviation, and is at present used on large multi-engined machines, such as pilot to alter the attitude of the lever in flight. th e Junker s G.38, whose undercarriages are com­ The two wheels are hydraulically inter-con­ posed of two independent units, each supporting nected with a piston at each end of the bar. two wheels in tandem. The Hill Pterodactyl in The size of the shock absorbers is inversely England, now being tested for possible military proportional to their distance, d and d , from 1 2 service, is fitted with a fixed tandem wheel the centre of gravity. When the wheels are undercarriage, which is partially enclosed in the lowered the machine rests on the ground in fuselage. The Messier monoplane is, as far position for a take-off; that is, with the wing as is known, the first machine to be fitted with a t the correct angle of incidence. The front a completely retractal le tandem wheel under­ wheel, in conjunction with the rudder bar, is carriage. This new undercarriage offers possi­ used to control ground manoeuvres at slow bilities for adoption on large multi-engined speed. machines, as the tandem wheels could be Several advantages are claimed by the retracted into recesses in the engine nacelles, or manufacturers for this new undercarriage. into a low wing, by the same system. The retractable tandem wheel system is said t o eliminate nosing over on the ground, owing Single-Spar Wing t o the fact that the two wheels are symmetrical t o the aeroplane. For a vertical displacement The machine built for experimental purposes given by the wheel there is a displacement of is a low wing monoplane fitted with a six- half the size for the centre of oscillation. Since cylinder in-line Hispano-Suiza 250 h.p. water- the centre of oscillation is very near to the cooled engine. The monoplane is a single centre of gravity of the machine, the mono­ seater and is aerodynamically very clean. The plane has therefore very good suspension. cantilever wing has a very thin section and is The extreme forward position of the front built up around a single metal box spar, on wheel allows for sudden and full application lines which will be clear from Fig. 4. The ribs of the brakes without danger of nosing over. are of wood. Long narrow chord ailerons The position of the machine when at rest, or occupy nearly all the trailing edge. For when taxying, gives the pilot better visibility lateral stability on the ground there is a skid tha n in conventional types of machines, in fitted with a shock-absorber on cither side of which the tail rests on the ground. the fuselage, which is attached to the wing spar at mid-section. It is intended eventually to make the two skids retractable as well. Retracting the Gear The Messier undercarriage consists of two The system of raising and lowering the under­ wheels, of which the forward is the larger, carriage is effected by the use of a lever with mounted in tandem and supported by forks three stop s (Fig. 2). To raise the undercarriage, fitted with oleo-pneumatic shock absorbers. a n A.B. Boysson system pump is fitted to The wheels are suspended at each end of a th e engine. Liquid under pressure induces the lever, B (Fig. 3), round which the aeroplane is raising movement by causing the opening balanced, the lever oscillating about a point 0, The above diagrams are reproduced from drawings of a trap in the bottom of the fuselage, close to the centre of gravity of the machine. in specifications of patents taken out by M. which is normally closed to form a part of the A control, the balance spring R, enables the Messier under surface. The wheels rise through the action of a screw. The upper part of the piston of this screw forces oil into a tank during the raising, where it is compressed ; thus accumu­ lating the necessary energy for lowering the wheels. The wheels are held in the retracted position by a valve. When the undercarriage is raised the pump allows the pressure to escape by an exhaust valve. It suffices to place the lever a t the stop position to disengage the pump. The pressure reduction which results induces the closing of the trap in the bottom of the fuselage. To lower the undercarriage, the pilot opens the valve which holds the wheels in retracted position. The wheels descend, opening the trap . The locking into normal position for landing is effected by valves, which can only be opened by the action of pressure created by th e pump at the moment of raising. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

A Novel Undercarriage

Aircraft Engineering and Aerospace Technology , Volume 6 (10): 1 – Oct 1, 1934
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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0002-2667
DOI
10.1108/eb029862
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Abstract

October, 1934 AIRCRAFT ENGINEERING 277 Th e Experimental Messier Monoplane with Tandem Whee l Retractable Landing Gear H E Société Francaise de Matériel d'Aviation, who manufacture aircraft accessories, such as brakes and oleo- pneumatic shock-absorbers, invented by the founder, the late Georges Messier, have recently built an experimental low wing monoplane fitted with an interesting tandem wheel retract­ able undercarriage embodying some of his ideas. The following description is illustrated mainly from various paten t specifications. The tande m wheel undercarriage is, of course, not new to modern aviation, and is at present used on large multi-engined machines, such as pilot to alter the attitude of the lever in flight. th e Junker s G.38, whose undercarriages are com­ The two wheels are hydraulically inter-con­ posed of two independent units, each supporting nected with a piston at each end of the bar. two wheels in tandem. The Hill Pterodactyl in The size of the shock absorbers is inversely England, now being tested for possible military proportional to their distance, d and d , from 1 2 service, is fitted with a fixed tandem wheel the centre of gravity. When the wheels are undercarriage, which is partially enclosed in the lowered the machine rests on the ground in fuselage. The Messier monoplane is, as far position for a take-off; that is, with the wing as is known, the first machine to be fitted with a t the correct angle of incidence. The front a completely retractal le tandem wheel under­ wheel, in conjunction with the rudder bar, is carriage. This new undercarriage offers possi­ used to control ground manoeuvres at slow bilities for adoption on large multi-engined speed. machines, as the tandem wheels could be Several advantages are claimed by the retracted into recesses in the engine nacelles, or manufacturers for this new undercarriage. into a low wing, by the same system. The retractable tandem wheel system is said t o eliminate nosing over on the ground, owing Single-Spar Wing t o the fact that the two wheels are symmetrical t o the aeroplane. For a vertical displacement The machine built for experimental purposes given by the wheel there is a displacement of is a low wing monoplane fitted with a six- half the size for the centre of oscillation. Since cylinder in-line Hispano-Suiza 250 h.p. water- the centre of oscillation is very near to the cooled engine. The monoplane is a single centre of gravity of the machine, the mono­ seater and is aerodynamically very clean. The plane has therefore very good suspension. cantilever wing has a very thin section and is The extreme forward position of the front built up around a single metal box spar, on wheel allows for sudden and full application lines which will be clear from Fig. 4. The ribs of the brakes without danger of nosing over. are of wood. Long narrow chord ailerons The position of the machine when at rest, or occupy nearly all the trailing edge. For when taxying, gives the pilot better visibility lateral stability on the ground there is a skid tha n in conventional types of machines, in fitted with a shock-absorber on cither side of which the tail rests on the ground. the fuselage, which is attached to the wing spar at mid-section. It is intended eventually to make the two skids retractable as well. Retracting the Gear The Messier undercarriage consists of two The system of raising and lowering the under­ wheels, of which the forward is the larger, carriage is effected by the use of a lever with mounted in tandem and supported by forks three stop s (Fig. 2). To raise the undercarriage, fitted with oleo-pneumatic shock absorbers. a n A.B. Boysson system pump is fitted to The wheels are suspended at each end of a th e engine. Liquid under pressure induces the lever, B (Fig. 3), round which the aeroplane is raising movement by causing the opening balanced, the lever oscillating about a point 0, The above diagrams are reproduced from drawings of a trap in the bottom of the fuselage, close to the centre of gravity of the machine. in specifications of patents taken out by M. which is normally closed to form a part of the A control, the balance spring R, enables the Messier under surface. The wheels rise through the action of a screw. The upper part of the piston of this screw forces oil into a tank during the raising, where it is compressed ; thus accumu­ lating the necessary energy for lowering the wheels. The wheels are held in the retracted position by a valve. When the undercarriage is raised the pump allows the pressure to escape by an exhaust valve. It suffices to place the lever a t the stop position to disengage the pump. The pressure reduction which results induces the closing of the trap in the bottom of the fuselage. To lower the undercarriage, the pilot opens the valve which holds the wheels in retracted position. The wheels descend, opening the trap . The locking into normal position for landing is effected by valves, which can only be opened by the action of pressure created by th e pump at the moment of raising.

Journal

Aircraft Engineering and Aerospace Technology – Emerald Publishing

Published: Oct 1, 1934

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