The Hirth F-23 is a twin cylinder,

horizontally-opposed A flat engine is a Internal combustion engine#Reciprocating engines, piston engine where the cylinders are located on either side of a central crankshaft. Flat engines are also known as horizontally opposed engines, however this is distinct fro ...

two stroke A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of t ...

, carburetted or optionally

fuel injected Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines. All compr ...

aircraft engine designed for use on

ultralight aircraft Ultralight aviation (called microlight aviation in some countries) is the flying of lightweight, 1- or 2-seat fixed-wing aircraft. Some countries differentiate between weight-shift control and conventional three-axis control aircraft with ailer ...

. It is manufactured by

Hirth Hirth Engines GmbH is an engine manufacturer based in Benningen, Germany. It is currently a part of the UMS Aero Group. Hirth began manufacturing aero engines in the 1920s, was taken over by Heinkel in WWII to develop the Heinkel-Hirth jet en ...

of Germany.Cliche, Andre: ''Ultralight Aircraft Shopper's Guide'' 8th Edition, page G-3 Cybair Limited Publishing, 2001. Purdy, Don: ''AeroCrafter - Homebuilt Aircraft Sourcebook'', page 72. BAI Communications.

Development

The F-23 is intended to compete with the

Rotax 503 The Rotax 503 is a , inline 2-cylinder, two-stroke aircraft engine, built by BRP-Rotax GmbH & Co. KG of Austria for use in ultralight aircraft.Raisner, William: ''LEAF catlog'', pages 6-105. Leading Edge Airfoils, 1995. As of 2011 the Ro ...

and is differentiated from the

Rotax Rotax is the brand name for a range of internal combustion engines developed and manufactured by the Austrian company BRP-Rotax GmbH & Co KG (until 2016 BRP-Powertrain GmbH & Co. KG), in turn owned by the Canadian Bombardier Recreational Product ...

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 Nikasil is a trademarked electrodeposited lipophilic nickel matrix silicon carbide coating for engine components, mainly piston engine cylinder liners. Development Nikasil was introduced by Mahle in 1967, and initially developed to allow Wankel ...

. Standard starting is

recoil start Rope start (also called pull start or ''rewind start'') is a method of starting an internal combustion engine, usually on small machines, such as lawn mowers, chainsaws, ultralight aircraft, small outboard motors and portable engine-generators. Al ...

. A belt reduction drive system,

fuel injection Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines. All comp ...

, 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 at 6150 rpm and at 5500 rpm.

Applications

Specifications (F-23)

References

External links

* {{Hirth aeroengines Hirth aircraft engines Air-cooled aircraft piston engines Two-stroke aircraft piston engines