Writhe Whirl wind J5 1/4 semi scale model
9-cylinder air-cooled radial engine.
4-stroke engine, inverted vertical valves with 2 valves per cylinder. The valves are controlled via pushrods. Cylinderheads and rocker box made of die cast aluminum. (can be ordered from
us). The cylinders are made of aluminum with cast iron liner.
The pistons are made of aluminium, dimension 25mm, with two pistonrings made of cast iron.
Length of stroke 28 mm.
Cylinder volume 124 cc.
Crankcase made of aluminium.
Crankshaft made of steel
Connection rods - one master connecting rod with 8 biconnecting rods organized in a rim on the master connecting rod's big end, are made of key steel.
Carburettor of needletype with feeding throught fanblower.
Lubrication by dropplubrication built into separate oiltank.
Fuel: Petrol with 2-3% oil addition.
Firing order: 1,3,5,7,9,2,4,6,8
Ignitionsystem: mechanical breakersystem with 6 volt coil and accumulator.
Alternatively Runtronic electronic system. Plugs - 9 pieces of NGK type ME - 8 or similar.
The engines rotation speed: 1500-4000 r.p.m.
Thrust approx 10kg
The engines total weight: approximatey 5.5 kg.
Airscrew: 24 x 18" - 24 x 20"