M.F.P. B 2
Flight, June 15, 1916.
THE M.F.P. TRACTOR BIPLANE.
SOME interesting and successful tests were carried out recently by Guy Gilpatric at Toronto, Canada, with a new tractor biplane that has been built in that city by the Poison Iron Works under the direction of Walter H. Phipps, who is responsible for its design. The M.F.P. biplane - the initials representing the names of Col. J. B. Miller, Walter L. Fairchild, and W. H. Phipps, the interested parties - is noteworthy on account of its steel construction. It differs from most other steel-constructed machines in that there is little or no welding, all parts and joints being made on jigs and assembled by bolting to special fittings. Most of the fittings are made, as far as possible, interchangeable, thus greatly facilitating repairs, and the number of spare parts is considerably reduced as the same fitting is used in many different places.
M.F.P. biplanes are designed in four styles, a fast single-seater scout, a two-seater scout (model D), a standard two-seater (model C), and a large-span two-seater (model B 2). With the exception of the first model, these machines differ only in the main planes, and they can be easily converted into seaplanes by the mounting of two single-step floats, which are attached to the same fittings that carry the land chassis. A factor of safety of 8 has been adopted in the design of all types. As the main characteristics of models B 2, C, and D are similar, the following description will be confined to the first-named, to which the accompanying scale drawings and photographs refer.
The main planes of a section tested at the Eiffel laboratory are of one-piece construction, very light and strong. They are built up with 3/4-inch grooved spruce battens nailed and glued to 3/16-inch hollowed, laminated birch and gumwood webs, assembled on two stout 2-inch tubular steel spars.
Each wing is trussed inside with four steel compression struts and strongly cross-braced, a construction which it is claimed adds materially to their rigidity. Top and bottom planes are separated on each side of the body by two pairs of streamline section struts, all of the same length and interchangeable on Models B 2 and C. The roots of the main spars fit into special drop-forged sockets, mounted on the fuselage for the lower plane and on the centre plane cellule for the top plane. These sockets are interchangeable, and are identical on both front and back spars. They are exceptionally light and strong, and have provision for double load wiring and front and back bracing, and, as in the case of the main spars and sockets, these struts have been subjected to most thorough tests for strength. All turnbuckles and wires have also been tested to insure the high factor of safety. The covering is Greeve's Irish aeroplane linen treated with four coats of dope.
The fuselage is rectangular in section, 30 ins. wide by 35 ins. deep in front, tapering to 14 ins. in a vertical knife edge at the rudder. The longitudinals are of steel tubing, very light, and braced with light steel tubes, joined with a special clamp, and then cross-wired. Throughout the construction of the whole machine the fuselage fittings are interchangeable. The third and fourth fuselage struts are extra large, and at the top they fit into plates which carry the extension struts to the upper plane cellule, while at the bottom they fit into simple clamps which carry the drop forgings forming lower plane attachments.
The top of the fuselage is streamlined off from the back of the pilot's seat to the tailplane by a turtle deck, which is readily detachable. Fabric is used for covering the fuselage aft of the engine portion, which is covered with sheet metal. On account of the narrow width of the fuselage - 30 inches - and the position of the passenger, well forward, with the pilot weir in back of the planes, both are afforded a good view both forward and downward.
Either a 130 h.p. Hall-Scott or the new 160 h.p. Bournonville is installed in models B 2 and C, but model D is equipped with a special 300 h.p. Duesenberg motor, fitted with electric starter. The engine is mounted on two stout laminated wood engine bearers, directly in front of the passenger and separated from him by a dash, through which a starting crank protrudes, enabling the engine to be started from the seat The petrol is fed to the engine from a large 60-gallon tank, which is sufficient for six hours' flight.
The landing chassis consists simply of two stout U frames of the same streamline section as the inter, plane struts, and cross-braced with a steel cross member of similar section. Two 26 x 4 in. disc wheels are mounted on a single axle, which is sprung on to the chassis frames by rubber shock absorbers and guided with radius rods. The tail skid is of ash, and is also sprung on with rubber shock absorbers.
With the seaplanes the two single step floats, which are of efficient design, are built up of spruce frames with mahogany planking and divided into five water-tight compartments.
The Dep. wheel and foot bar type of control is fitted, double-wired throughout with 5/32 in. steel cable.
The following are the complete specifications of all three models:-
Model B 2 Model C Model D.
No. of seats 2 2 (single or 2 (single or
double control) double control)
Top 45 ft 10 ins. 38 ft. 10 ins. 38 ft.
Bottom 34 ft 4 ins. 38 ft. 10 ins. 38 ft.
Chord 5 ft 3 ins. 5 ft. 6 ins. 5 ft. 6 ins.
Gap 5 ft 8 3/4 ins 5 ft. 8 3/4 ins 5 ft. 6 ins.
Area 410 sq. ft. 392 sq. ft. 380 sq. ft.
Length 26 ft. 6 ins. 20 ft. 6 ins. 26 ft. 10 ins.
(loaded) 48 to 90 m.p.h 49 to 95 m.p.h 60 to 130 m.p.h.
(empty) 1,370 lbs. 1,420 lbs. 1,000 lbs.
Useful load 900 lbs. 900 lbs. 220 lbs.