Flight, January 1931
THE PRUDDEN-WHITEHEAD MONOPLANE
An American All-Metal Commercial Machine
WE give this week some brief non-technical details of a recent all-metal monoplane produced by the Atlanta Aircraft Corporation, of Atlanta, U.S.A. - namely, the
Prudden-Whitehead commercial monoplane, the design of which was recently approved by the U.S. Department of Commerce.
The Prudden-Whitehead all-metal monoplane embodies several novel features, and while the unusual features to be noted can in no way be considered radical, it is their efficient application and execution of design that has produced very favourable impressions during its demonstrations in the eastern States of America.
This machine is all-metal throughout, of duralumin and duralumin alclad, and is of the low-wing type. The fuselage is one of the very rare, full monocoque types, the bulkheads being formed from sheet duralumin over which the corrugated alclad "skin" is laid.
The monoplane wing is of full cantilever construction, carrying three main spars of duralumin, with alclad covering. It is to be noted that the corrugated metal wing covering carries a portion of the stresses. Ailerons are inset, and the tail-surfaces conventional with balanced rudder.
Possibly the most notable of the novel features is the installation of the engine mount nacelles in the leading edge of the wing, carrying a modified N.A.C.A. cowling with collector ring in the leading edge.
The landing gear is of conventional split type, with an Aerol shock strut installation on the main wheels and oildraulic strut at the tail wheel, Bendix brakes, with high-pressure tyres are standard equipment.
In the appointments of the passenger cabin, every consideration has been given the comfort and safety of passengers. Colours are soft browns and green, pleasingly blended. Ventilation is furnished by specially-constructed adjustable ventilators at each seat, the plate glass windows being fixed. The pilot's cockpit windows carry shatterproof glass, two of which are movable. A remarkably broad range of visibility is to be had not only from the pilot's seat, but from the cabin as well. Seats are comfortably upholstered in soft chrome leather. Attention to detail is shown in the equipment of a wash room and toilet.
Everywhere attention to details which may promote safety has been given, in both the design and in construction as well. Power is furnished by three Wright J6-R760 motors, and the installation is so made that no factor can affect more than one motor at one time. Fuel, baggage compartment, and all weighty constructions are placed below the passenger cabin. Mail contractors have evidenced interest in the considerable load space, available without the use of the passenger compartment for this purpose.
The following is the P.M. monoplane specification of this machine :-
Span overall 66 ft. 6 in.
Length overall 44 ,, 10 ,,
Height 14 „ 7/8 „
Wing area 662-5 sq. ft.
Wheel tread 18 ft.
Width 5 ft. 0 in.
Aisle width 1 ,, 3 „
Seat width 1 ,, 6 ,,
Length, passenger cabin 10 „ 0 „
Height 6 ,, 10 ,,
Height (average) 5 ,, 5 ,,
Seats 8 to 10 ,,
High speed 145 m.p.h.
Cruising speed 124
Landing speed 55
Take-off (with full load) 7 seconds.
Take-off run 384 ft.
Climb, at sea level 1,220 ft. per min.
Absolute ceiling 17,000 ft.
Service ceiling 15,000 „
Altitude maintained with 2 motors 10,000 ,,
Net weight 5,200 lb.
Useful load 2,535 „
Gross weight 7,735 „
Pay load 1,330 ,,
Power plant (3 Wright J6-R760, 240 h.p.) 720 h.p.
Wing loading 12-25 lb. per sq.ft
Power loading, 3 motors 10-75 lb. per h.p.
Power loading, 2 motors 16-1
Gliding ratio 9-5 to 1
Fuel capacity 150 gals.
Fuel consumption per hour 30 „
Oil consumption per hour 1-37 „
Miles per gallon fuel at cruising speed 4-12.
Endurance 3 hours
Range 620 miles
Cleanness of design and workmanship, the effectiveness of the cowlings, and streamlining, have effected an efficiency which is responsible for very good performance characteristics of this machine.
The 'plane now produced is an eight-place job, designed for transport use, but the makers point out the fact that the design is elastic and may be applied to larger or smaller construction without material loss of efficiency.
The designer, Mr. George H. Prudden, has long been identified with the development of all-metal multi-motored aircraft, and to him has been accredited much of the advancement in that branch of the industry, having formerly been associated with Mr. William B. Stout during the development of the Stout metal aircraft. He may well be pleased with his latest accomplishment.
The sales activities of the company are under the direction of Mr. Edward Whitehead, who was formerly connected with a General Electric merchandising organization, and also headed a larger real estate development on the Pacific coast. Mr. Whitehead served with credit throughout the late world war, seeing active service on both the western and Italian fronts with the air forces.