VALACH VM 70S1-4T

Only 2.5 mm higher than the VM-60 
Swings big propellers with high efficiency in an reasonable RPM range
Exceptionally pleasing sound caused by big Honda valves and clever valve timing
Spontaneous throttle response and smooth mid-range transition
Small frontal section with the valve train, carburetor and exhaust behind the cylinder
Nickel-Silicon plated cylinder surfaces
Completely enclosed valve train
Only one camshaft
Three crank bearings
Valach microprocessor controlled ignition with auto advance and retard
Ignition is designed for a 2s LiPo battery
VM-Motors are designed using the latest tools and techniques

The carburettor is placed behind the engine, resulting in an very narrow engine which fits into nearly every cowling.

Being a four stroke with a large capacity produces a very realistic full-size aircraft sound. With a relatively small silencer the sound level is very low rather like a small saloon car.
 
The Valach VM-70 S1-4T is a four stroke OHV engine with two valves per cylinder, running on petrol/oil mixture. Valves and their seats are manufactured by Honda, ensuring a very high quality. The fully encapsulated valve train reduces sound as well as ensuring the rocker arms are well lubricated.
The Fiala propellers are very efficient, this being due to minimal blade thickness. They sound especially good on four stroke engines. Ideal Fiala two blade propeller sizes for the VM 70: 24x14", 26x10" and 26x12". 
The fuel consumption is approximately 50% compared to that of a two-stroke engine with the same displacement. A 300cc fuel tank lasts for about 15-20 minutes of flying time.