P.Bowers Curtiss Aircraft 1907-1947 (Putnam)
Model MF (Model 18)
The MF was a greatly improved two-seat training flying-boat that was evolved from the Model F through the experimental BAT and BAP models. The designation stood for Modernized F. Structurally, the MF was more like the HS design than the F, but it was in the weight-power-size class of the F and was intended as a replacement for it.
A very prominent feature of the MF was the use of sponsons on each side of the forward hull as introduced on the America and used on many subsequent flying-boats. Initial powerplant was the 100 hp Curtiss OXX-3 but experimental installations were made with the 150 hp Wright-Hispano and the 150 hp Curtiss K-6, a new six-cylinder inline engine that was essentially half of the 400 hp K-12 developed for Curtiss by Charles Kirkham.
Curtiss built six MFs at Garden City on one Navy order and sixteen of 47 on a second order that was cancelled by the Armistice. The Navy built 80 more in the Naval Aircraft Factory at a cost of $5,821 each less engine for the first 20 and $3,771 each for the last 20. After the war, Curtiss continued limited production of the MF for the civil market under the name of Seagull and also converted former Naval MFs to Seagulls for civil use. Other Curtiss and Navy-built MFs that became surplus were acquired by the Cox-Klemin Aircraft Co of College Point, Long Island, which rebuilt them for the civil market in the early 1920s.
Trainer flying-boat. Two pilots. 100 hp Curtiss OXX-3.
Span 49 ft 9 in (15,16 m); length 28 ft 10 in (8,78 m); height 11 ft 7 in (3,53 m): wing area 402 sq ft (37,34 sq m).
Empty weight 1,850 lb (839 kg); gross weight 2,488 lb (1,128 kg).
Maximum speed 72 mph (115,87 km/h); climb 2.400 ft (731 m) in 10 min: service ceiling 4,100 ft (1,250 m); range 345 miles (555 km).
Model 18 - Seagull
This was a refurbished wartime MF Navy flying-boat sold commercially in 1920. In spite of such improvements as the 160 hp Curtiss C-6 engine, sales were poor, approximately 16, because of direct competition from surplus Navy models and from other firms that offered their own rebuilt versions of the MF. Technical data as for MF except:
Empty weight 1,191 lb (540 kg); gross weight 2,726 lb (1,236 kg). Maximum speed 76.5 mph (123.11 km/h); cruising speed 60 mph (96.55 km/h); climb 260 ft/min (1.32 m/sec); service ceiling 5,900 ft (1,798 m); range 288 miles (463 km).
G.Swanborough, P.Bowers United States Navy Aircraft Since 1911 (Putnam)
The Curtiss MF was an improved 1918 model flying-boat that was intended to replace the venerable F model that had been on hand since 1912. While the letters of the designation stood for Modified F there was no detail resemblance between the two other than the general configuration of a wooden-hulled pusher flying-boat. The MF drew upon the later design experience of the H-boats and the F-5Ls and used a flat-sided hull with additional forward buoyancy provided by sponsons added to the sides. The initial order to Curtiss was for six machines. This was followed by a production order for 47, but because of the Armistice, only the first 16 were delivered. An additional 80 were ordered into production at the Naval Aircraft Factory after the war.
Curtiss, meanwhile, quickly brought out a civil version of the MF under the name Seagull. Some of these, fitted with Wright-Hispano engines of 150 hp, or the new Curtiss K-6s of 150-160 hp were modified to carry as many as four people. Curtiss even tried an amphibious version in its quest to capture the sportsman-pilot market in the face of competition from cheap war-surplus machines, but the Seagull in its different versions was not a commercial success.
Navy interest in an amphibious version was reflected by a contract given to the Elias brothers aircraft company, Buffalo, NY, for the conversion of one of the NAF MFs (A5484) to an amphibian. As the MFs, both Curtiss and Navy-built, became surplus to the needs of the service, they were bought up by the Cox-Klemm Aircraft company College point, Long Island, and modified for civil use.
TECHNICAL DATA (MF-Boat)
Manufacturer: Curtiss Aeroplane and Motor Co, Inc, Garden City, LI, and Buffalo, NY; and Naval Aircraft Factory, Philadelphia, Pennsylvania.
Type: Flying-boat trainer.
Accommodation: Pilot and instructor side by side.
Power plant: One 100hp Curtiss OXX.
Dimensions: Span, 49 ft 9 in; length, 28 ft 10 in; height 11ft 7 in, wing area, 402 sq ft.
Weights: Empty, 1,850 lb; gross, 2,488 lb.
Performance: Max speed, 72 mph at sea level; initial climb, 10min to 2,400ft; service ceiling, 4,100 ft; range 345 st miles.
Serial numbers: A2345-A2350; A4403-A4449 (last 31 cancelled); A5483-A5562 (by NAF)