Hirth F-23

The Hirth F-23 is a twin cylinder, horizontally-opposed, two stroke, carburetted or optionally fuel injected aircraft engine designed for use on ultralight aircraft. It is manufactured by Hirth of Germany.

Development
The F-23 is intended to compete with the 50 hp Rotax 503 and is differentiated from the Rotax powerplant by offering a horizontally-opposed cylinder layout. The F-23 uses free air cooling and piston-ported induction, with dual Bing 34mm slide or optional diaphragm type carburetors. The cylinder walls are electrochemically coated with Nikasil. Standard starting is recoil start. A belt reduction drive system, fuel injection, tuned exhaust and electric start are optional.

The engine runs on a 50:1 pre-mix of unleaded 93 octane auto fuel and oil. Recommended time between overhauls is 1000 hours.

The F-23 produces 50 hp at 6150 rpm and 40 hp at 5500 rpm.

Applications
• Aeronix Airelle

• Air Sports AIRector 120

• Aurore MB 02-2 Mini Bulle

• DAR-23

• Fisher FP-303

• Monnett Moni - motorglider

• Rotorschmiede VA115

• Sadler Vampire

• Solid Air Diamant LP

• Spacek SD-1 Minisport

• TechProAviation Merlin 100

• Team Mini-Max AeroMax

• TeST TST-1 Alpin

• Wings of Freedom Phoenix 103