Home Up XF-40 HIRTH Electric

H35 (for Helicopters)

H35 is a NEW 2-cylinder inline two-cycle engine by Hirth of Germany. It has reed valve controlled with electronic fuel injection and Nikasil coated cylinders. It has been claimed as one of the highest power to weight ratio available on the 65 HP engine market designed specifically for light helicopters with electronic fuel injection and constant revolutions. Factory recommended TBO is rated at 500 hours at 75% power. The warranty of the crank shaft is 3 years. This is the one many have recommended.  If you are interested in this engine, please e-mail us, or contact Hirth of Germany directly.

Engine Type: 2 cylinder two cycle inline reed valve controlled helicopter engine  
Displacement: 625 cc  (38.1 cu in)
Horsepower: 47,8 kW (65 HP) at 6300 rpm 
Torque: 72,4 Nm (53.4 ft. lb) at 6300 rpm
Mixture formation: Multipoint fuel injection system
Cooling: Forced Fan Cooling
Ignition: CDI programmable
Fuel: Unleaded Auto Gas, min. 93 Octane
Starter: Electric, 12 Volt DC
Generator: 250W, 12 Volt DC
Lubrication: Auto lubrication with 6-way oil pump for 2-stroke oil.
Complete engine weight: 31,7 kg (69,7 lbs.)  incl., electric starter, exhaust
Time Between Overhaul: 500 Hours

Other Hirth Aircraft Engine Line

All Hirths have Al-Nikasil coated cylinders for superior performance and reliability. Al-Nikasil in simple terms is a nickel based material, applied in a paste form. When super heated it becomes part of the cylinder itself. Al-Nikasil provides for a super low coefficient of friction allowing Hirths not only to produce more hp than our nearest competitor but also to run with greater efficiency and reliability. Hirths crankshafts are 4130 chrome moly steel. Heads, rings, block casting, connecting rods and associated components are all of the highest grade alloys available today.

Hirth F23 Boxer Engine 50hp

If you prefer an opposed cylinder engine, then this one's for you. F-23 puts out an amazing 50hp at only 6000 rpm and provides 42ft/lbs. of torque. All with a total weight of only 87 lbs. This engine can handle any part 103 ultralight and most single seat experimentals. Now available with improved belt re-drive and exhaust system.

F-23 W/Electric Start & Diaphragm carburetor


F-23 W/Electric Start & Electronic fuel injection


Belt reduction drive





Dual 34mm slide or optional diaphragm carbs or optional electronic fuel injection

Engine Type:

Opposed - 2 cycle, two cylinder

Fuel Pump:

Optional auxiliary external pneumatic




Fuel mixed with oil @ 50:1 or optional oil injection




Counter clockwise, viewed from output end




12 volt electric, optional recoil
250 watt/20 amp alternator standard




Free air Cooled by prop blast

HP Output:

50hp @ 6150rpm


84lbs, including reduction unit, full exhaust, and electric start


42ft.lbs @ 6150rpm

Reduction Units:

Belt drive - 1.8:1, 2.2:1 and 2.5:1 ratios available


Dual CDI
(Capacitive digital Ignition.)

Drive Coupling:


Hirth F-30s 85/110hp

Flagship of the Hirth product line; the F-30s are available in two versions, the F-30 80hp and the awesome F-30/2c 110hp. The Hirth F-30s are the premiere power plants for the Experimental and Homebuilt industry.

F30 80 Hp shown with force fan air cooling and G-40 gearbox.

Free Air Electric Start


Free Air Electric Start G40 Gear Box


Fan Cooled Electric Start


Fan Cooled Electric Start G40 Gear Box


Optional Fuel Injection


F30ES fuel injected 110hp shown in free air version with fuel injection and G-40 gearbox.

Free Air-2 carb Electric Start


Free Air 2 carb Electric Start G40 Gear Box


Fan Cooled carb Electric Start

$ 9669.00

Fan Cooled carb Electric Start G40 Gear Box


Fuel Injection Option


All prices are subject to change without notice.