Maintenance Manual STEMME S10-VT
Date of Issue: Jan. 01, 1998
Page 3-17
Amendment Nr. 14
Date: Nov. 30. 2007
A4011121_B23.doc
Doc. No. A40-11-121
3.4 Power Plant (Fig. 3.4.a)
3.4.1 Engine
Engine description:
See "Maintenance Manual (Heavy Maintenance) for ROTAX Engine Types
ROTAX 912 and 914 Series”, section 71
Upper Engine Attachment:
A tubular steel frame at the upper engine flanges, mounted in two vibration
absorbing elements in the upper lateral tube of the fuselage frame
Lower Engine Attachment:
A separate tubular steel frame at the lower engine flanges in two vibration
absorbing elements in the forward lateral framework junctions
Type:
ROTAX 914 F2/S1 (modified ROTAX 914 F Aircraft engine, propeller shaft
design with flange for fixed pitch propellers)
The ROTAX 914 F2/S1 is modified by STEMME and based on the type ROTAX 914 F2. The modification
was completed as a co-operation with ROTAX and with acceptance of ROTAX. The base engine ROTAX 914
F2 is certified according to JAR-E / FAR 33. It is turbocharged and has an electronic dual-ignition system.
The modified version ROTAX 914 F2/S1 was specially developed for the model S10-VT, a derivative of the
powered glider STEMME S10. The engine modifications are certified together with the S10-VT according to
JAR 22. The modified version ROTAX 914 F2/S1 has the STEMME (internal) production No. 11AM-M.
The ROTAX 914 F2/S1 is based on the Engine-Production No. 37.914.0120.06 (ROTAX 914 F2 without
mech. tachometer and without external generator) resp. on No.37.914.1120.06 (ROTAX 914 F2 without
mech. tachometer, but with external generator). The external generator is standard equipment for the
S10-VT. By definition, it is not considered as part of the engine but an accessory of the airframe.
Due to special requirements for installation in the central fuselage, the following modifications were made:
The most significant modification is the relocation of the turbocharger unit to the aft of the engine to stay
within the outlines of the S10-VT fuselage. The turbocharger unit is supported by five struts aft of the
engine. In between the turbocharger and the carburetors a supercharger intercooler is installed.
Relocation of the turbocharger unit required modifications of the exhaust system. The exhaust bends are
attached to the turbocharger by springs, positioning bends in spite of the high thermal stress.
It was also necessary to modify the layout of the oil pipes for the turbocharger.
The exhaust bends and the muffler are shrouded by temperature-resistant material, thus thermally
isolating the system from the engine bay. The turbocharger unit and the airbox are isolated by radiation
protective shields.
The original ROTAX engine mounting is not used. STEMME specially developed an engine mounting for a
centre installation, consisting of two upper and one lower supporting elements.
In the liquid cooling system, the combined function of the expansion reservoir and refill container was split
up in two separate containers, with the expansion reservoir located above the engine and the refill
container on the left side of the fire-wall.
The ignition unit is installed above of the engine slightly behind the original position.
The throttle levers on the carburetors have been slightly modified (modification does not affect the throttle
rigging of the original engine) and additional springs have been installed (pulling towards full-power
position) to compensate for friction due to the long control cables in between cockpit and engine bay.
Engine performance data of the ROTAX 914 F2/S1 are identical to those of the ROTAX 914 F:
T/O power
84.5 kW (113.2 hp)
Max continuos power:
73.4 kW (98.4 hp)
Max. T/O RPM:
5800 RPM
Max. continuos RPM:
5500 RPM
Reduction ratio (engine reduction gear):
1 : 2.43
Max. Propeller RPM:
2387 RPM
