Lawrence (Larry) Matanski founded in 1980 Airmaster Inc. in Renton, Washington, to produce and market the Avalon 680 amphibian aircraft he was designing. The all-metal aircraft was powered by a single 750 shp Pratt & Whitney PT6A-135 turbine engine mounted atop the wing and cabin, driving a pusher propeller, which rotated between the twin-boom tail. The prototype N767LB flew for the first time in October 1983.
The six-seat cabin was unpressurized; the nose-wheel landing gear was retractable with the main wheels stored into the sponsons. The sponsons were attached to stubs and from these stubs two struts supported the wing where they connected at the twin-booms.
The production model would have a 24 in (0.56 m) fuselage stretch, additional cabin windows, optional pressurization, 62 sq.ft (5.76 sq.m) increase of wing area, sponsons moved 5 in (0.13 m) out, a 4 in (0.10 m) wider rear hull, fuel tanks in the stubs, and larger fins and rudder.
From land the Avalon needed 800 ft (244 m) to get airborne, from water this was 1,200 ft (366 m). Landing run on land was 650 ft (198 m), on water this was 700 ft (213 m). Maximum landing weight was 5,100 lb (2,313 kg), cruise speed was 200 mls (322 km)/h, stall speed 65 mls (105 km)/h.
An twin-engined Avalon Twin Star 800 was developed to be powered by two Allison 250-C20Bs providing a total of 820 shp would drive a single pusher propeller. Also an Avalon Twin Star 1000 and a military A-1200 Guardian have reportedly been designed, but except for the Avalon 680 prototype no further aircraft have flown.
Avalon 680 Larry Matanski Aviation Memorial Photo Tribute
Avalon 680: Avalon Twin Star 800: Avalon Twin Star 1000: A-1200 Guardian:
projected 7-seat twin-engined 820 shp version
projected 7-seat twin-engined 1,000 shp version
projected 1,200 shp military version
Specifications (Avalon 680)
Max T/O weight:
One 750 shp Pratt & Whitney PT6A-135 turbine engine
44 ft 0 in (13.41 m)
32 ft 0 in (9.75 m)
12 ft 6 in (3.81 m)
264 sq.ft (24.53 sq.m)
3,300 lb (2,404 kg)
5,300 lb (1,497 kg)
230 mph (370 km/h) at 16,000 ft (4,877 m)
2,200 ft (671 m)/min
900 mls (1,448 km)