A lot has happened with ultralights over the past 30 years, one of those is an improvement with engines. Some engines from the early 80′s are still good options, such as the Rotax, Kawasaki, and Zenoah lines. However, improvements have occurred in regards to electronic ignition, reduction drives, dual ignition, fuel injection and overall weight. Simplex Aeroplanes is currently a dealer and offering Hirth engines for sale with our kits or packaged individually.
 Hirth F-33 --- 28 hp |
The Hirth F-33 is an excellent option to help ensure you meet Part 103 requirements for an Ultralight (less than 254 lbs). The engine with a recoil start and 2.5:1 reduction drive, muffler, and carb, weighs only 40 lbs! Adding electric start only adds 5 lbs more. That’s half the weight of a similar 28 hp Rotax 277. With ultralights, saving 40 lbs is a huge deal. Factory recommended TBO is rated at 1000 Hrs. @ 75% power. Standard equipment includes fuel pump, spark plugs, air filter, recoil starter, complete exhaust system and dual CDI ignition for added reliability. When ordered with optional electric start the starter solenoid and voltage rectifier/regulator are included. Standard mounting is plate type from bottom of engine.
Prices: F-33 with Electric start and 2.5:1 reduction – $3,427 |
| Model: | F-33 | Carburation: | Single 34mm slide or optional diaphragm type or optional fuel injection |
| Engine Type: | 2 cycle, single cylinder | Fuel Pump: | Auxiliary external pneumatic (12VDC electric pump when fuel injected) |
| Bore: | 76mm | Lubrication: | Fuel mixed with oil @ 50:1 |
| Stroke: | 69mm | Rotation: | Counter clockwise, viewed from output end |
| Displacement: | 313cc | Starter: | Recoil or optional electric start – Note: Electric start only available in conjunction with belt re-drive |
| Compression: | 9.5:1 | Cooling: | Free air Cooled by prop or slip stream (Optional fan cooling available on special order) |
| HP | 28hp @ 6500rpm | Weight: | 35lbs including exhaust sys. – 40lbs W/re-drive – 45lbs W/elec. start |
| Torque: | 25ft.lbs @ 6000rpm | Reduction Sys.: | 4V belt drive available 1.8:1, 2.2:1, & 2.5:1 ratios.(Up or down pos.) |
| Ignition: | Dual CDI | Drive Coupling | Optional centrifugal clutch available (can not be used with belt drive) |
 Hirth F-23 -- 50 HP |
Looking for more HP and the cool look of opposed cylinders? Maybe you want a smoother running engine than what a 1 cylinder 2 stroke can provide. The F-23 puts out an amazing 50hp at only 6150 rpm and provides 42ft/lbs. of torque. All with a total weight of only 84 Lbs. The same weight as a Rotax 447 or a half VW but more power than both! This engine can handle any part 103 ultralight, some two seat “ultralight like” experimentals and most single seat experimentals. Opposed pistons cancel out each others internal inertia forces resulting in an amazingly smooth running engine. |
PRICES:
F-23 W/Electric-Start, Slide carburetor, and 2.5:1 reduction —- $5,300
F-23 W/Electric-Start, Diaphram carburetor, and 2.5:1 reduction — $5,560
F-23 W/Electric Start, Electronic fuel injection and 2.5:1 reduction — $7,400
| Model: | F-23 | Carburation: | 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 |
| Bore: | 72mm | Lubrication: | Fuel mixed with oil @ 50:1 or optional oil injection |
| Stroke: | 64mm | Rotation: | Counter clockwise, viewed from output end |
| Displacement: | 521cc | Starter: Alternator: |
12 volt electric, optional recoil 250 watt/20 amp alternator standard |
| Compression: | 9.5:1 | Cooling: | Free air Cooled by prop blast |
| HP Output: | 50hp @ 6150rpm | Weight: | 78lbs, including reduction unit, full exhaust, and electric start or71lbs with recoil start reduction unit and full exhaust |
| Torque: | 42ft.lbs @ 6150rpm | Reduction Units: | Multi V Belt drive – 1.8:1, 2.2:1 and 2.5:1 ratios available |
| Ignition: | Dual CDI (Capacitive digital Ign.) |
Direct Drive coupling also Available | Reduces total weight by 10 lbs. |
