The Specification

Self Launching Motor Glider

The system
Rear mounted folding propeller, connected to the engine via a set of drive shafts, with the engine mounted behind the wing.
The fin to be both dorsal and ventral so that the propeller can rotate when the aircraft is on the ground.

Desired Performance:
All-up mass, 454kg.
Take-off distance, 400m @ 1500m ASL.
Fuel capacity, 20 litre.
Fuel consumption per launch, 1 litre.
Cruise capability, 120kph @ 5 litre/hour.

Desired Characteristics:
Cost effective to make and fit to an ASW 20.
The engine must have reliable starting characteristics under all possible conditions.
The engine must be able to produce height-maintaining power immediately after cold start and climb power in a further 60 seconds.
The aircraft must still be able to be transported by trailer.
The engine operating procedures must be simple.
A failed start must not alter the aircraft’s glide angle.
Engine noise must be reduced as much as is practical.

The specifications have evolved to the following:

Single cylinder, reed valve, water cooled, fuel injected two stroke engine with net power of 30kW @ standard conditions.

Speed Reducer:
Poly v-belt drive.

Noise Reduction:
Engine compartment and cowl assembly are designed to achieve maximum silencing.
Engine exhaust and inlet system are designed to achieve maximum silencing.

Drive Shafts:
Four, 4130 steel shafts with flexible rubber couplings and self-aligning bearings.

The propeller blades are from Ivo-Prop USA and have ground adjustable pitch.
The folding hub has synchronous folding and centrifugal deployment with spring stops to absorb blade deployment shock.

Cooling System:
The cooling system consists of an aluminum heat exchanger cowled to an electric fan which runs when the engine is running.
The synthetic coolant reservoir is from VW.

The cockpit section of the ASW 20 forward of the canopy attaches to the space-frame of 4130 tubing.
The wings, undercart, mixing box, cooling system, engine, exhaust, drive-train and tail section are all mounted to the space-frame.

Space-Frame Cover:
A light composite cover gives this frame a glider-like shape and is easily removed for inspection and maintenance purposes.

Tail Section:
The tail section is made from composites and will bolt to the space-frame in front of the leading edge of the fin.
The stabilizer and elevator will be the same profile as the ASW 20 but the span will be 200mm more.
The fin and rudder will also have the same profile and area as the ASW 20 but will have a higher aspect ratio.

Fuel System:
An aluminum tank is fitted forward of the wings and has a 20 litre capacity.

Main Wheel:
The aircraft uses the same wheel and brake assembly as employed in the ASW 20.
The retract mechanism extends a further 200mm and has rubber shock absorbers,

Tail Wheel:
The tail wheel is non steerable and attaches to the ventral fin.