Editing Motor glider (section)

===Self-launching motor gliders===
[[File:WankelPP.jpg|thumb|Powerplant from a [[Schleicher ASH 26]]E self-launching motor glider, mounted on a test stand for maintenance at [[Alexander Schleicher GmbH & Co|Alexander Schleicher]] in [[Poppenhausen, Hesse|Poppenhausen]], Germany. Counter-clockwise from top left: propeller hub, mast with belt guide, radiator, Wankel engine, muffler shroud.]]
Self-launching retractable propeller motor gliders have sufficient thrust and initial climb rate to take off without assistance, or they may be launched as with a conventional glider. The engines also have a starter motor and a large battery to allow the engine to be started on the ground, and an alternator to recharge the battery. A two-blade propeller is typically coupled to the engine via a belt [[reduction drive]]. In older designs, the propeller alignment must be checked by the pilot using a mirror, before it is retracted into the fuselage; however in current production gliders, propeller alignment is fully automatic.

Another solution is the [[single-blade propeller]] that offers the advantage of a smaller opening in the fuselage to retract the engine.

Internal combustion engines can benefit from mounting in the fuselage, rather than on the propeller mast. This allows them to be connected to a larger muffler for reduced noise when operating, something which is mostly relevant to European operation. It also allows the belt tension to be relieved when the engine is retracted to extend the life of the belt and bearings. 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.

Self-launching engines are equipped with a throttle that allows the engine power to be adjusted for ground operations.  Self-launching engines are typically in the range of 50–60&nbsp;hp (38–45&nbsp;kW).  The higher engine output power requires liquid cooling with a separate radiator mounted on the propeller mast.  Engines commonly used are [[Two-stroke engine|two-stroke piston engines]], or [[Wankel rotary engine]]s.<ref>{{cite web|url= http://www.alexander-schleicher.de/englisch/produkte/ash26/e_ash26_main.htm |title= Alexander Schleicher GmbH & Co., ASH 26 E Information|access-date=24 November 2006|archive-url= https://web.archive.org/web/20061008125929/http://www.alexander-schleicher.de/englisch/produkte/ash26/e_ash26_main.htm |archive-date= 8 October 2006}}</ref>