Weslake engines are designed and developed by the company founded by Harry Weslake (1897-1978). The firm has been operated since 1981 as Weslake Air Services, Ltd. and is located in Hastings, Sussex, UK. The Weslake firm is best known in the US, probably, for designing and building the engines used in Dan Gurney's Formula One Eagle race cars in 1967, but they have been involved in engines for a variety of other usage. Harry Weslake was involved with Jaguar engines in the 1930s and was very active in engine design until his death.
Two separate product lines of engines for light aircraft, air-cushion vehicles (ACV), and remotely piloted vehicles (RPV) were pursued by Weslake in the 1970s through the 1990s. One product line, begun by Weslake Aeromarine Engines, Ltd. of Ashford, Kent, UK, developed two-stroke cycle engines for RPVs, with later production by Normalair-Garrett, Ltd. (NGL) of Yeovil, Somerset, UK, a part of the Westland Group of companies. The second product line, begun by Weslake & Co. of Rye Harbour, Sussex, UK, developed four-stroke cycle aircraft engines for ultralight aircraft, with production by Emdair, Ltd. of Hastings, E. Sussex, UK. Each of these engine lines is dealt with separately below.
Weslake Air Services continues to develop aircraft engines such as the two-cylinder, four-stroke cycle Weslake W50 (O-49) that is available as a direct drive or geared engine. The direct-drive version is built by Weslake and is described below among the Emdair engines as the Weslake W50 (O-49) since its technical features have evolved from the Weslake-designed, Emdair-built CF 077, CF 092, and CF 112. The geared version is manufactured, under license in the US, as the Hexadyne P60; see also the Hexadyne Website. Weslake also has participated recently in development of the Dieselair (UK) 100hp four-cylinder, opposed-piston two-stroke cycle diesel aircraft engine. For more information, see the Weslake Website.
Weslake Aeromarine, later Normalair-Garrett, Ltd. (NGL), aircraft engine development began in the early 1970s when the UK Ministry of Defence approached Weslake as a potential engine supplier for RPVs. NGL took over manufacture of this line of engines in May 1979 and continued development and production into the late 1980s. Most of the Weslake/NGL engines were two-stroke cycle HOAE. NGL later developed the WAEL 600N turbojet with 118# of static thrust for unmanned aircraft. The core of this gas turbine engine was common to a mass-produced diesel engine supercharger. Several two-stroke, two- and four-cylinder HOAE were developed in a displacement range from 4 to 93 cu. in. One four-stroke engine, the Weslake 1527 (O-93) was also developed as described below. The Weslake/NGL engines had type numbers and model numbers which referred to their displacement in cc.
O-4 (2-Stroke) -- {N/A / N/A / 3.7} / {N/A / N/A / 60}
2cyl; Weslake Type 060; 5hp@N/A rpm; 1978-1979; Wt = N/A.
Direct drive.
J78-79.
Applications: None found.
O-7 (2-Stroke) -- {1.811 / 1.378 / 7.1} / {46 / 35 / 116}
2cyl; Weslake Type 116; 8hp@6500rpm; 1978-1982; Wt = 10#.
Direct drive.
J78-79toJ81-82.
Applications: (UK) BAe Dynamics Stablileye Mk.2, Mk.3 RPVs.
O-12 (2-Stroke) -- {2.165 / 1.654 / 12.2} / {55 / 42 / 200}
2cyl; Weslake Type 200; 12hp@6500rpm; 1981-1982; Wt = 18#.
Direct drive.
J81-82.
Applications: (UK) BAe Dynamics Stabileye Mk.3 RPV.
O-17 (2-Stroke) -- {2.598 / 1.575 / 16.7} / {66 / 40 / 274}
Same bore and stroke as O-33.
Same bore as O-21, O-42.
2cyl; Weslake Type 274, NGL WAM 274; 18hp@6500rpm; 1978-1985; Wt = 16-17#.
Major production engine in different versions for RPV, ACV, and powered hang gliders; direct drive, single ignition.
J78-79toJ84-85.
Applications: (UK) Cranfield (Cranfield-Marconi) A2 Machan; Shorts Skeet target drone; Westland Wideye RPV helicopter.
O-21 (2-Stroke) -- {2.598 / 1.969 / 20.9} / {66 / 50 / 342}
Same bore and stroke as O-42.
Same bore as O-17, O-33.
2cyl; Weslake Type 342, NGL WAM 342, NGL WAEL 342; 26hp@6000rpm-30@8000 (TO); 1981-1988; Wt = 19-28#.
Major production engine in different versions for RPV and target drones; direct drive or geared to N/A.
BGP; Brinks; J81-82toJ87-88.
Applications: (UK) AEL Snipe Mk.IV; British Aerospace Stabileye RPV; GEC Avionics Phoenix, TTL Banshee.
O-26 (2-Stroke) -- {N/A / N/A / 26.2} / {N/A / N/A / 430}
Same bore and stroke as O-52.
2cyl; Weslake Type 430; 40hp@N/Arpm; 1978-1982; Wt = 25#.
Direct drive; single or dual ignition.
J78-79toJ81-82.
Applications: None found.
O-33 (2-Stroke) -- {2.598 / 1.575 / 33.4} / {66 / 40 / 547}
Same bore and stroke as O-17.
Same bore as O-21, O-42.
4cyl; Weslake Type 548; 36hp@N/A rpm; 1978-1982; Wt = 36#.
Direct drive.
J78-79toJ81-82.
Applications: None found.
O-42 (2-Stroke) -- {2.598 / 1.969 / 41.8} / {66 / 50 / 684}
Same bore and stroke as O-21.
Same bore as O-17, O-33.
4cyl; NGL WAM 684; N/A hp@N/A rpm; 1983-1984; Wt = N/A.
Direct drive.
J83-84.
Applications: None found.
O-52 (2-Stroke) -- {N/A / N/A / 52.5} / {N/A / N/A / 860}
Same bore and stroke as O-26.
4cyl; Weslake Type 860; N/A hp@N/A rpm; 1978-1982; Wt = N/A.
Direct drive; single or dual ignition.
J78-79toJ81-82.
Applications: None found.
O-93 -- {3.543 / 2.362 / 93.2} / {90 / 60 / 1527}
4cyl; Weslake Type 1527; 100hp@5500rpm; 1978-1982; Wt = 100#.
Four-stroke cycle engine based on well-proven Weslake production components; developed for RPV applications.
J78-79toJ81-82.
Applications: None found.
Weslake & Co., later Emdair, engine development began around 1980. Emdair took over manufacture of this line of engines in c.1984 and continued development and production into the mid 1990s. Recent Weslake four-stroke developments are the Weslake W50 (O-49) and the CF 122/E (O-122). All of the Weslake/Emdair engines are four-stroke cycle, two-cylinder HOAE. Several HOAE were developed in a displacement range from 73 to 150 cu. in. The Weslake/Emdair engines had model numbers which referred to their displacement in cu. in. The Emdair engines had dual electronic ignition systems. Some early Weslakes had carburetors, but many Emdairs had direct fuel injection.
O-49 -- {3.622 / 2.362 / 48.7} / {92 / 60 / 797}
2cyl; Weslake W50; 48hp@4800rpm; 1995-present; Wt = 98#.
Marketed in the US by Flite-Lite, Inc. [(707) 277-7442]; approximately 30 had been sold (KP4/05).
Air-cooled, electronically-controlled, single-ignition, direct-drive engine. An alternative, geared version is built under license in the US as the Hexadyne P60.
KP4/05; Weslake Website; Hexadyne Website.
Applications: (UK) BAe Phoenix UAV (updated developmental prototype of original NEC Avionics Phoenix).
O-73 -- {N/A / N/A / 72.7} / {N/A / N/A / 1192}
2cyl; Weslake W40/50-73-02; 40hp@2600rpm, 50@3400 (TO); 1982-1986; Wt = 85#.
Electronically-controlled ignition to assist in operation with as lean a fuel-air mixture as possible.
J82-83toJ85-86.
Applications: None found.
O-77 -- {3.740 / 3.500 / 76.9} / {95 / 88.9 / 1260}
Same stroke as O-92.
2cyl; Weslake W42/55, Emdair CF 077A; 45hp@3090rpm, 60@3600 (TO); 1984-1995; Wt = 104-110#.
Major production models. Direct-drive, four-valves per cylinder, direct fuel-injection, dual-ignition engine with FADEC system, alternator and electric starter.
BGP; J84-85toJ94-95.
Applications: None found.
2cyl; Emdair CF 077B; N/A hp@N/A rpm; 1987-1995; Wt = N/A.
As CF 077A, but geared to 0.722 with torsional damping.
BGP; J87-88toJ94-95.
Applications: None found.
O-92 -- {4.094 / 3.500 / 92.2} / {104 / 88.9 / 1510}
Same stroke as O-92.
2cyl; Emdair CF 092A; 52hp@3075rpm, 75@3400 (TO); 1988-1995; Wt = 112-115#.
Major production models. Direct-drive, four-valves per cylinder, direct fuel-injection, dual-ignition engine with FADEC system, alternator and electric starter.
BGP; J88-89toJ94-95.
Applications: None found.
2cyl; Emdair CF 092B; N/A hp@N/A rpm; 1991-1995; Wt = N/A.
As CF 092A, but geared to N/A with torsional damping.
BGP; J92-93toJ94-95.
Applications: (US) Verilite (DeVore) Model 100 Sunbird ultralight (originally planned to use CF 077B).
O-98 -- {4.000 / 3.902 / 98.1} / {101.6 / 99.1 / 1607}
2cyl; Emdair CF 100A; 62hp@2800rpm, 75@3400 (TO); 1986-1989; Wt = 115#.
Electronically-controlled ignition to assist in operation with as lean a fuel-air mixture as possible.
J86-87toJ88-89.
Applications: None found.
O-112 -- {4.350 / 3.780 / 112.4} / {110.5 / 96 / 1841}
2cyl; Emdair CF 112A; 64hp@3270rpm, 85@3600 (TO); 1988-1995; Wt = 128#.
Major production models. Direct-drive, four-valves per cylinder, direct fuel-injection, dual-ignition engine with FADEC system, alternator and electric starter.
J88-89toJ94-95.
Applications: None found.
2cyl; Emdair CF 112B; N/A hp@N/A rpm; 1991-1995; Wt = N/A.
As CF 112A, but geared to 0.694 (25/36) with an epicyclic gearbox and, presumably, torsional damping.
J91-92toJ94-95.
Applications: (US) Verilite (DeVore) Model 100 Sunbird ultralight.
O-118 -- {4.626 / 3.500 / 117.7} / {117.5 / 88.9 / 1928}
2cyl; Weslake W65/75-118-02, W65/80-118-02, W70/85-118-02; 50hp@2540rpm, 85@3500 (TO); 1981-1984; Wt = 130-145#.
Direct drive; first Weslake engine in this family (not developed further by Emdair).
J81-82toJ83-84.
Applications: (Romania) ICA-Brasov IS-28-M2A motorglider. (UK) Vinten-Wallis WA-116/W gyroplane.
O-122 -- {4.528 / 3.799 / 122.3} / {115 / 96.5 / 2005}
2cyl; Weslake CF 122/E; 80hp@3000 rpm, 85@3200 (TO); 1995-present; Wt = 145#.
Marketed in the US by Flite-Lite, Inc. [(707) 277-7442]; approximately 30 had been sold (KP4/05).
Direct-drive, four-valves per cylinder, direct fuel-injection, dual-ignition engine with FADEC system, alternator and electric starter.
KP4/00, 4/01, 4/02, 4/03, 4/05.
Applications: None found.
O-150 -- {4.921 / 3.937 / 149.8} / {125 / 100 / 2454}
2cyl; Emdair CF 150A; 95hp@2800rpm, 110@3400 (TO); 1985-1987; Wt = 130#.
Direct drive.
J85-86toJ86-87.
Applications: None found.