Valach Engines

VM 85 B2-FS

With the Valach VM 85B2-FS the legendary Valach “voice” and smooth running characteristics are now available also for your smaller sized models. The VM 85B2-FS is the perfect engine for our Sopwith Pup, our 33% scale Pitts Special S1-S, the 33% scale Piper L4 Grasshopper and the quarter scale Bücker Jungmeister from Paolo Severin. The VM 85B2-FS sounds just like the famous VM 120B2-4T, pleasing but powerful, and at a warm low frequency.

  • Nickel-Silicon plated cylinder surfaces
  • Completely encapsulated valve train
  • CNC milled crankcase
  • Sensational smooth running and high torque
  • Spontaneous throttle response and smooth midrange transition
  • Extremely low vibration throughout the RPM range because of the four stroke principle
  • Honda valves and valve seats
  • Walbro carburetor
  • Valach microprocessor controlled ignition with auto advance and retard
  • An ignition integrated voltage converter allows the use of two LiPo cells
  • VM-engines are now being produced with state of the art machines and methods
  • Rapid spares delivery and repair service from Germany by Toni Clark practical scale GmbH

The VM 85B2-FS is also available with a starter. With the current version of the VM 85B2-FS the starter can be retrofitted anytime.

Due to being a four stroke boxer twin, the low vibration is nothing but sensational, and torque is really high. The response to the throttle being opened is so smooth without the slightest attempt to surge, making the Valach VM 85B2-FS absolutely ideal not only for scale models but also for aerobatic models and glider towing.

Being a four stroke with a large capacity, it 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.

Image: The valve train of the VM 85B2-FS is fully encapsulated, improving rocker arm lubrication and the valve train runs quieter. The crankcase is manufactured from solid aluminum.

The Valach VM 85B2-FS is a four stroke OHV engine running on petrol/oil mixture. We have tried many oils and recommend Valvoline SynPower 2T oil. Our BEL-RAY H1R, although excellent for two strokes, is not ideal for four strokes, as it burns very well without deposit, therefore not much gets past the piston. With Valvoline Synpower 2T a lot more oil gets through to the crankcase. In Germany we recommend Aral Ultimate 102, as the smell is not so penetrating, it can be stored without deteriorating and it does not contain ethanol! If in your country petrol does not contain any ethanol, you can use any brand you like.

The fuel consumption is only approximately 50% compared to that of a two-stroke engine with the same displacement.

Valves and their seats are manufactured by Honda, ensuring a very high quality. The totally enclosed valve train reduces sound, as well as ensuring the rocker arms are well lubricated.

The processor controlled ignition allows easy starting and an exceptionally smooth running in all throttle settings.

The Valach engines VM 85B2-FS looks just like an original aero engine, only smaller, it runs smoothly like an original aero engine and above all it sounds like an original aero engine. The legendary perfectionist Henry Royce of Rolls Royce always insisted that an engineering construction to be right must look right. I defy anyone to tell me the Valach Twin does not look right.



85 cc


42 mm


32 mm


280 mm

Length from engine mount to prop hub

167 mm

Weight with prop washer and prop bolts

2,940 g

with Starter: 3,420 g

Weight - complete with ignition, prop washer and prop bolts

3,120 g

mit Starter: 3,540 g

Ignition voltage range

4.8 - 9 Volt

RPM range

1000 - 6000 1/min

Fiala Prop 2-blade


Fiala Prop 3-blade


Fuel: Valvoline SynPower 2T / Petrol

VM 85 B2-FS

More Information

Flight testing of the VM 85B2-FS took place in spring and summer 2016 in a Pitts Special S1-S built from our kit. Eddy Pot had lots of fun doing the tests, as you clearly see from the above picture. The combination of the wounderful Valach exhaust note with the tremendous power and outstanding flight characteristics due to the big, scale size 26×12″ prop is marvellous. There is no better engine for our Pitts!

This Y-fitting makes it easy to remove the unwanted oil from the pressure tube of the carburetor. Loop-in the two “branches” into the pressure tube and extend the “trunk” about 6-12 cm to lead it to the lower side of the cowling. Place the Y-fitting underneath the carburetor and the surplus oil will be gathered into the “drainage tube” and can be dumped from time to time, without removing the cowling.

Inside the Valach VM 85B2-FSIniside the Valach VM 85B2-FS

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