Motor glider
Another solution is the single-blade propeller that offers the advantage of a smaller opening in the fuselage to retract the engine.
The drawback of this arrangement is that engines fixed low in fuselages are more difficult to pre-flight and service, and highly stressed power transmission belts should not be bent or twisted.
The higher engine output power requires liquid cooling with a separate radiator mounted on the propeller mast.
Some TMGs are equipped with folding wings to allow them to fit in standard small airplane T-hangars.
Some TMGs, like the Europa or the Phoenix, can also be supplied with interchangeable wings or wingtips so that they can be flown as a standard touring aircraft as well as a TMG.
[6] The landing gear configuration on TMGs usually incorporates two fixed main wheels, allowing it to be taxied on the ground without a wing walker.
Since the additional drag of the stopped propeller and landing gear reduces their gliding performance, TMGs are seldom used in competition.
The retractable propeller is usually mounted on a mast that rotates up and forward out of the fuselage, aft of the cockpit and wing carry-through structure.
They have a single-axle retractable main wheel on the fuselage like most unpowered gliders, so they do require assistance during ground operations.
The S10-VT variant has a two-position variable-pitch propeller and a turbocharger on the engine, which allows the aircraft to cruise at altitudes up to 30,000 feet (9,000 m).
Although most motor gliders have gasoline-fueled internal combustion engines, a number of electric-powered self-launchers have been developed including the Lange Antares 20E and 23E, Schempp-Hirth Arcus E, Schleicher AS 34Me, Pipistrel Taurus Electro G2, Silent 2 Targa LE (Lithium Electric), and the closely related Air Energy AE1 Silent, Yuneec Apis 2, Yuneec EViva, Alpaero Exel, Aériane Swift, Electravia and Alatus AL12.
11 different types, from 7 manufacturers, such as the Alisport Silent 2 Electro, use the front electric sustainer (FES) system with a folding propeller in the nose.
The generally accepted practice is to get in position for landing at a suitable airport, or off-airport out-landing field, before extending the propeller and attempting an engine start.
Gliders without an engine are lighter and, as they do not need a safety margin for an engine-start, they can safely thermal at lower altitudes in weaker conditions.
An opposing view is that motor gliders are against the spirit of the sport, and, more importantly, that they sometimes give pilots a false sense of security.
If the trainee chooses an inappropriate field, or misjudges the approach, the instructor can apply power and climb away safely.
In South Africa, Touring Motor Glider (TMG) is an independent National Pilots License category under Recreation Aviation, Part 62, subpart 17.
