Flight, August 1922
THE IRWIN "METEORPLANE"
THE Irwin Aircraft Co., of Sacramento, Cal., U.S.A., recently put on the market a small sporting biplane called the "Meteorplane" Model MT, which embodies several interesting features. We are indebted to our American
contemporary Aviation for the following brief particulars of this little machine.
It is a single-seater tractor biplane, and was designed to meet the demand for a small lightweight aeroplane of conventional design that the average aero enthusiast could afford to have and operate. The "Meteorplane" has a quick get away (160 ft. run), good climb, is speedy, yet at the same time has a very low landing speed, insuring the greatest degree of safety. In landing, it comes to rest after a run of 110 ft. Consistent with these qualities, the design and construction embrace very light weight, yet the factor of safety at any point of the whole machine is more than five. The power loading is 26 lbs., while the wing loading is only a little over 3 1/2 lbs./sq. ft.
The main planes are adjustable as regards their fore and aft position, provision being made for sliding them along the fuselage. This enables a perfect balance being obtained at all times. Hollow spruce spars are employed, and the rib webs and cap strips are of yellow pine and spruce respectively. The interplane struts, of which there are four, two being close up to the fuselage, are of I-form, and are built up of three-ply wood. Thus incidence wires are eliminated. Irwin No. 4 wing section is employed, the dynamical stability of which is almost the same as the Eiffel 32. Ailerons are fitted to the top plane only, and the lower plane, which is of shorter span than the top, is set at a dihedral angle.
Of good streamline form, the fuselage is of box-girder construction, with ash longerons and four three-ply panels holding the body in shape The whole framework is wire braced from engine panel to stern post, and the covering is sheet metal at the nose and doped fabric elsewhere.
The under-carriage is of novel, yet simple construction, and consists of two wide members forming an "A" - viewed from the front - which is attached to the fuselage at three points, the apex at the top of the fuselage, and the middle at the lower longerons. The lower extremities of these members are slotted to receive the rubber sprung axle, which carries two 20 in. by 3 in. wheels.
The empennage is composed of a non-lifting horizontal stabiliser, to which are hinged divided elevators, and a triangular vertical fin, to which is hinged a rudder. The latter is of sufficient area to insure complete control when handling the machine on the ground. Conventional stick and rudder bar control is used.
A two-cylinder air-cooled engine of 15 h.p. is mounted in the nose, and drives a 4 ft. 11 in. tractor screw of 3 ft. pitch at 1,900 r.p.m.
The principal characteristics of the "Meteorplane" are as follows :-
Span (upper) 19 ft. 10 ins.
Span (lower) 19 ft. 1 in.
Chord 3 ft. 1 in.
Gap 2 ft. 10 ins. to 3 ft. 2 3/4 ins.
Overall length 13 ft. 9 ins.
Overall height 5 ft. 10 1/2 ins.
Angle of incidence 2° 30'.
Dihedral (lower) 3°.
Area of main planes 105 sq. ft.
Area of tail plane 9 sq. ft.
Area of elevators 8 sq. ft.
Area of fin 1 1/2 sq. ft.
Area of rudder 5 sq. ft.
Weight of machine empty 240 lbs.
Weight loaded 396 lbs.
Weight /h.p. 26 lbs.
Weight/sq. ft. 3 3/4 lbs.
Speed range 32-56 m.p.h.
Climb in 15 mins. 2,500 ft.
Gliding angle 1 in 7.
Range 1 hr. 45 mins.