This is the .70 SZ-H Ring Engine from O.S. designed with the
FAI F3C Pilot in mind.
FEATURES: Ringed for long life.
3-needle carb for ultimate tuning precision. (Settings are covered on
pages 14 & 15 of the manual)
High Speed: 2 turns OUT
Medium Speed: 1 tunn OUT
Idle Mixture: Refer to picture on page 14
Two extra mounting lugs on front allow modelers to mount engine
securely in helis.
Designed with the FAI F3C competitor in mind, allowing 3D pilots an
edge over the standard .60 size engine.
Throttle assembly reference marks make it easy to note and restore
finely tuned settings after maintenance.
Front and rear ball bearing-supported crankshaft reduces friction
Large heli cylinder head offers generous cooling fin area, with
increased webbing on crankcase front for heat dissipation.
Installs in the same space as a .61 engine.
INCLUDES: One .70SZ-H Ringed Helicopter engine
#8 OS Glow Plug and Decals
REQUIRES: Muffler & Fuel
SPECS: Displacement: 11.50cc (.702cu in)
Bore: 25.8mm (1.016in) Stroke: 22.0mm (.866")
Power Output: 2.5PS, 2.47 HP at 16,000 RPM Weight: 553.5g (19.5oz)
Practical RPM Range: 2,000 - 18,000 RPM
Crankshaft Thread Size: 5/16-24
Length: 81.3mm Backplate to the front of the crankcase
Width: 42.6mm width of engine neglecting the mounting flanges
25mm distance between mounting hole centers
60mm Distance from rear mount to front mount centers
52mm Side to side centers of rear mounting holes
42mm Side to side centers of foremost mounting holes
42mm distance between mounting holes for exhaust
Needle Settings: High Speed: 2 turns out from fully closed
Mixture Control (low speed) indentation on screw head
straight vertical (up and down)
Medium Range: 1 turn open
COMMENTS: Engine is shipped with the carb lightly fitted. Be sure to tighten
prior to use.
COMMENTS: This engine will fit in most .60 size helicopters, and should work
well without the need for gear changes.
updated rjm 8-19-02
updt lmm 4/14/09