Introduction
A wide selection of engines and engine kits are available in the market for use in General Aviation aircraft and other applications. Produced by US, European and other manufacturers, together with an extensive range of related parts and accessories, they intend to cover diverse application needs of their prospective users. Although most aviation engines today are piston engines (also commonly referred to as reciprocating engines as they use reciprocating pistons to convert pressure into a rotational motion) rotary engines are sometimes seen powering aircraft while (like their piston counterparts) they are also encountered in automobile, marine and other applications.
As part of our "one stop shop" philosophy, AviationEU Group companies have developed long-standing relations with widely but also less known manufacturers of aviation (aircraft) engines and their distributors. Engines from TEXTRON LYCOMING, CONTINENTAL AEROSPACE TECHNOLOGIES (formerly CONTINENTAL MOTORS), BPR ROTAX are commonly used to power modern General Aviation aircraft, but other engine builders are also manufacturing quality engines in pre-assembled or kit versions for home built / experimental, ultra lights and light sport aircraft (LSA). After all, a "good engine" is not necessarily related only to the reputation of the manufacturer but also has to do with how best this engine fulfils user project design and production needs.
Like most aviation parts, intended application certification requirements often serve as the first filter in selecting an engine.
In general, Certified aviation engines are considered those included in the '' Type Certificate'' of an aircraft model ensuring that both the aircraft and all its component parts (including propellers, engines, etc.) is compliant with all applicable airworthiness requirements and safety standards. Certified aviation engines are sourced from specific manufacturers holding respective approvals from their respective Civil Aviation Authorities (CAA) and respective authorities in other countries based on bilateral signed agreements.
Non-Certified aviation engines are those used in amateur-built aircraft such as airplanes, gliders, or rotorcraft built by individuals and used for non-commercial, recreational purposes. They are licensed by the U.S. Federal Aviation Administration (FAA) as “Experimental” or ultralights falling under the FAA’s FAR (Federal Aviation Regulation) Part 103. Similar regulations issued by the European Aviation Safety Agency (EASA) apply in the EU and other countries. This brief guide is intended to serve as a reference document for our existing and prospective aviation engine buyers focusing on applications where non-certified engines could be used. We have tried to create an aircraft piston engine collection that would cover the diverse needs of our customers, from aviation enthusiasts constructing their own aircraft to ultra-light and sport aircraft airframe builders looking for cost-effective powerplant solutions. These engines are offered in a diverse horsepower range from 60 hp to several hundred hp. Parts and accessories are also offered for each engine.
Although this guide is not intended to be an exhaustive presentation of every aviation engine available in the market, it aims to cover those non-certified engines, engine kits and related parts and accessories already listed in our Web Platform for Supplies (www.ecommerce.aviationeu.supplies) but also others not currently listed which can be supplied through our co-operations with the respective manufacturers and their distributors.
This guide is structured in 2 sections. The first provides general information on aircraft engines with explanations on commonly used terms describing their features while the second includes an overview of different engines for different ranges of delivered horsepower.
Content provided is FOR REFERENCE ONLY and it is based on published information by their manufacturers, our communications with them or other published material (articles, studies, etc.). Variations may apply to engine specifications due to their constant upgrading by the respective manufacturers. Our company cannot be held responsible for the validity and accuracy of such information. For further information, or clarifications please contact us or visit our visit AIRCRAFT ENGINES Section of our Web Platform for Supplies.
Section A: Aviation Engines at a Glance
Aviation engines come in various certified and non-certified models with different power outputs, number of cylinders, cylinder configurations, features and specifications (direct drive or with gearboxes, different fuel delivery and cooling systems, and so on) which makes the selection of the right engine a quite complicated process. In addition, different terms are used for describing engine features which may be well known to mechanics and airframe building companies but sometimes not very easily understood by light aircraft owners and experimental (home) aircraft builders. Below we provide a brief explanation of major terms used in engine presentations.
Piston vs Rotary Engines 
An aircraft piston engine, also commonly referred to as a reciprocating engine, is an internal combustion engine that uses reciprocating pistons to convert pressure into a rotational motion. The aircraft piston engine operates on the same principles as the engines found in most automobiles. In terms of their cylinder configuration, common aircraft piston engines can be classified as inline, V, flat or radial. Inline or “straight” engines have all their cylinders lined up in a row and usually found in 3, 4, 5, and 6-cylinder variations. V style engines have their cylinders configured in a V shape and typically found in engines with 8 or more cylinders. Flat horizontally opposed engines (also known as “boxer” engines) are arranged so that the cylinders are oriented horizontally, opposing each other when firing. Common cylinder variations include 4 and 6 cylinders. Radial engines (aka "star engines") have their cylinders arranged radially around a central crankcase. 
Rotary engines (not often used nowadays) look similar to radial, but they are attached to the airframe only by a crankshaft and the entire engine rotates with the propeller. They are essentially standard Otto cycle engines, with cylinders arranged radially around a central crankshaft (just like conventional radial engines), but instead of having a fixed cylinder block with rotating crankshaft, the crankshaft remains stationary, and the entire cylinder block rotates around it.
Ready to Fly vs Engine Kits
Ready to Fly engines are pre-assembled and test run by their manufacturers prior to their delivery. Engine kits are complete packages of engine components supplied by their manufacturers to be used for local assembly by the buyer as per manufacturer’s instructions.
Direct Drive vs Geared Engines
The terms “direct drive” or “geared”/gearbox” are also common in engine typology. In a direct drive aircraft engine, the propeller is directly connected to the crankshaft of the engine, without the use of a gearbox. This design simplifies the power transmission system and can result in reduced weight and mechanical complexity. Direct drive engines are commonly used in small general aviation aircraft and some light sport aircraft.
Avgas vs Mogas Fuel
In the past, most aviation reciprocating (piston) engines were typically designed to run on aviation gasoline (Avgas, the most common being 100LL) although Diesel aviation engines were also seen powering GA aircraft. Avgas has a higher-octane rating than automotive gasoline (Mogas) to allow higher compression ratios, power output, and efficiency at higher altitudes. STCs were used to allow certified aircraft to operate with Mogas. Nowadays, aviation engines can run on both Avgas and Mogas subject to their manufacturer’s specified limitations.
Certain manufacturers also offer JET-A and multi-fuel capable engine solutions.
Aircraft Engines vs Automobile Engine Conversions for Aircraft Use
Some aviation engines included in this guide have been exclusively designed and developed for aircraft like those of Lycoming, Continental, MwFly and others while other engines and engine kits are based on conversions of automobile (car) engines for aircraft installations. 
A notable example of such conversions is VW engines which have been used to power light aircraft since the Second World War. The commonly used VW is Type 1 although Type 4 and Wasserboxer (Water boxer) type are also used.
Type1 is the original Beetle engine made with a capacity of 1100 to 1600 cc. This is the engine most used today in aircraft. The crankcase is made of magnesium. Aircraft engines typically have a capacity of 1600 to 2400 cc and a power of 50 to 90 HP. Type 4 is a larger and heavier engine resulting as a new development of the air-cooled boxer concept with original capacity between 1700 and 2000 cc. The Wasserboxer is a development of the Type 1 engine with respective conversions featuring a displacement of 2000 to 2700 cc. VW Type 1 engine conversions are offered by AeroConversions (AeroVee engine kits), Great Plains (engine kits), Revmaster, Hummel and other engine makers while Type 4 engines are offered by Grob and Wasserboxer type by Sauer and Limbach respectively.
Apart from VW, other automobile engine conversions powering aircraft include Mitsubishi and Honda car engines used in Viking aircraft engines, Subaru in Stratus powerplants, etc.
Other Terms
Other terms are often encountered in the presentation of engine features like carbureted or fuel injected engines, air or liquid cooled, turbocharged, EFI (electronic fuel injection), PSRU (Propeller Reduction Gearbox), FADEC and others.
Carburetors house a float-type chamber, where fuel is collected and distributed to the induction system. Based on the Venturi principle, where air speeds up in the manifold due to a narrowing of the chamber, fuel is vaporized and mixed with air prior to entering the engine. The volume of air flowing through the induction system is the primary means of fuel metering. The throttle controls how much air goes into the engine, while the mixture controls how much fuel is mixed with the air.
Fuel injected systems use a fuel pump to push fuel through a metering system. Then, the fuel flows through injector lines to each cylinder. In fuel injected engines there is no air mixed with the fuel in the metering system. A servo regulator measures airflow entering the engine, and meters fuel accordingly for the proper mixture. The fuel is vaporized and mixed with air just before entering the cylinder. Fuel injected engines often have an electric fuel pump as a backup, to ensure fuel can be pushed through the metering system even if the engine driven pump fails.
Air-cooled engines are simpler in design, lighter, and generally more resistant to damage due to their fewer components. However, they can be less efficient at removing heat from the engine, which can lead to greater temperature variations and potential hot spots. Liquid-cooled engines are generally more complex and heavier but typically more efficient at heat removal allowing for a more consistent operating temperature and better overall engine performance and longevity.
A turbocharger is a turbine driven, forced induction device that is utilized in a piston engine to enable it to produce more power. In a normally aspirated piston engine, intake gases are drawn into the cylinder by the reduced pressure created by the downward stroke of the piston. The mass of the air drawn into the cylinder, in part, limits the power production of the engine, A turbocharger recovers waste energy from the engine exhaust stream and uses it to power a turbine which in turn drives a compressor. This compressor draws in ambient air, compresses it, and then feeds it into the engine intake resulting in a greater mass of air and, proportionally, a greater amount of fuel entering the cylinders on the intake stroke. This increase in air and fuel results in the turbocharged engine being more powerful and efficient than its naturally aspirated counterpart.
FADEC system consists of a digital computer, called an electronic engine controller (EEC) or engine control unit (ECU), and its related accessories that control all aspects of aircraft engine performance.
Section B: Overview of Aviation Engines
Engines with horsepower up to 85 hp
Aircraft engines in this power output category are manufactured by different manufacturers and include among others 
HKS 60 hp 700E horizontally opposed 2-cylinder, 4-stroke engine,
ROTAX® 65 hp UL DCDI MOD.99 65 hp 2 stroke, 2 liquid cooled cylinder engine as well as ROTAX® bestselling 912 UL 80 hp 4-stroke 4-cylinder engine.
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At the top side of this power category a worth considering option is Australian Jabiru 2200 four-cylinder engine rated at 85 hp (see engine presentation in the next power category section).
Automobile engines converted to aircraft use and related engine kits are also offered from HUMMEL ENGINES and GREAT PLAINS AVIATION SUPPLY providing VW-based engine kits in front drive-direct drive, flywheel drive and reduction-drive configurations.
Sonex Aircraft AEROCONVERSIONS 80 hp AeroVee 2.1 is yet another engine kit offered in this power category together with the 100 hp AeroVee Turbo engine kit mentioned in the next category.
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Engines with horsepower between 85 hp and 160 hp
Aircraft engines with power output in the 85 to 160 hp range can be supplied from various manufacturers with ROTAX® engines playing a significant role in this market segment. ROTAX® engines can be used in light, light sport, ultralight and homebuilt aircraft.
ROTAX® 912, 914 and newer 915/916 series of aircraft engines are relatively lightweight, compact engines with air-cooled cylinders and liquid-cooled cylinder heads. These engines have been designed for higher rpm than their Lycoming and Continental counterparts with a built-in propeller speed reduction unit (gearbox) to optimize propeller rpm. ROTAX® engine range includes their best-selling carbureted 80 hp 912 UL (mentioned above), the 100 hp 912 ULS as well as the turbocharged powerplants (the 914 and their newer powerplants 915 iS, with a 141 takeoff and 135 continuous horsepower up to 15,000 feet for excellent mid-altitude performance and 916 iS dynamic engine with best power-to-weight ratio.
Certified FAA and JAR/EASA versions models are also offered. Respective models include: ROTAX® 912 F, 912 S, 912 A, 912iSc2/912iSc3, 914 F2/914 F3, 915 iScA/ 915 iSc C24, 916 iScA/ 916 iSc C24.
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ROTAX® Engines’ Alternatives
Non-certified powerplants alternative to ROTAX® engines are also offered by different engine builders such as the Italian MWfly, developed specifically for use in light aircraft and other applications.
MWfly 4-cylinder horizontally opposed (boxer type) aeronautical engines feature 100% liquid cooled cylinders (compared to liquid and air-cooled cylinders of their ROTAX® counterparts) with electronic ignition and fuel injection with dual ECU computers as standard. Their two SPIRIT engine lines, SKYLINE and REDLINE include several direct or geared drive transmissions (depending on the model) developed respectively for touring and performance flying. They can be used in a wide range of LSA and experimental single-engine or twin-engine airplanes and other aircraft (STOL, helicopters, gyrocopters, hang gliders, seaplanes and drones).
SKYLINE engines deliver 100, 122, 135 & 140 hp while their REDLINE counterparts deliver 115, 135 & 160 hp. The 135 and 160-hp direct drive engines are high-rpm units for helicopter use only.
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Australian Jabiru engines are another option due to their light weight, simplicity, affordability and a significant power-to-weight ratio. Construction relies heavily on aluminum through the crankcase and cylinders—silicon carbide and nickel coated—for low weight and rapid heat transfer. Two engines are offered, the four-cylinder 2200 rated at 85 hp and the bestselling six-cylinder 3300 rated at 120 hp. The 132-pound 2200 is found in smaller Zenith and Sonex airframes, RV-12s and Titan Tornados while the more powerful 3300 is typically encountered in larger Zenith airframes and Arion, RANS and Sonex models. Both are simple engines in design and operation. A single Bing slide-type carburetor, mechanical fuel pump and inductive ignitions are used along with fixed-timing ignition distributors. Both the alternator and inductive ignition are integral to the engine designed to work as long as the engine is rotating.
AC Company (AC Aero) in Japan offers Combined Cycle Technology (CCT) Higgs Diesel engines operating on JET A, diesel and gaseous fuels such as hydrogen. Apart from aviation these engines can be used on drones, generators, compressors, marine or land vehicles, military and other space / weight single fuel restricted designated use applications. Their FALCON FL150 engine, weighing only 147lbs. (67 kgs) has a power output of 115 hp in naturally aspirated (NA) and up to 130 hp in fuel injection (FI) engine versions. With a service ceiling of 30,000′ the FL150 engine is ideal for LSA, kitplane builds, drones and other applications. Various other models of higher horsepower compete with engines of other manufacturers in the next category.
Belgian manufacturer D -Motor also offers 4-stroke side valve (flathead) boxer engines featuring multipoint fuel injection, electronic ignition, and liquid cooling. Their two models, the 4-cylinder LF26 and the 6-cylinder LF39 provide a maximum continuous power of 93.68 hp (58 Kgs) and 125 hp (78Kgs) at 3100 rpm respectively. Mostly used in helicopter and drone applications due to their light weight, low MoGas consumption, low rpm (low noise) and their nearly flat torque capabilities. These engines are sold to OEM aviation manufacturers only.
Lower priced automotive engine conversions for aircraft use can also be supplied either as pre-assembled engines or engine kits by US manufacturers within the ROTAX® engine power range. Noticeable examples include different engine models from US manufacturers Aero Momentum, Viking and Sonex AEROCONVERSIONS 100 hp AeroVee Turbo engine kit.
Aero Momentum engines are available in upright or low-profile configurations and feature a single overhead Cam, 4 valves per cylinder, FADEC system standard, sequential injection, knock sensor, 2.588:1 gearbox rated to 225 hp, liquid cooling, Helmholtz tuned cold air induction system, tuned stainless steel exhaust headers (Optional). TBO 2000 hours. Aero Momentum engine product portfolio includes:
- Aero Momentum 100 and 112 hp AM13 1.3 L SOHC 4-Cylinder,16-Valve engines, a cost-effective alternative to the ROTAX® 912, Continental O-200 and other similar aircraft engines.
- Aero Momentum 117 and 131 hp AM15 1.5 L SOHC 4-Cylinder,16-Valve engines,
Sonex Aircraft AEROCONVERSIONS 100 hp AeroVee Turbo is offered as a complete kit package and can be installed in any suitable homebuilt aircraft.
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Viking Aircraft engines are based on used automobile engines removed from cars that are uneconomical to repair. Their models come in multiple horsepower ranges, 90 hp (2022 - 2023 1.2 L Mitsubishi Mirage), 130 hp (2020 - 2021 1.5 L Honda Fit), 150 hp (2022 -2023 1.8 L Honda HRV) and 195T 195 hp (2022 - 2023 1.5 L Turbocharged Honda Accord). Features of their Honda based engines include liquid cooling, direct gasoline fuel injection system, 4 coil ignition system, lifetime chain camshaft drive, integral exhaust manifold cast into cylinder head, off-set crank shaft and friction reduction coating throughout the engine, variable valve lift and timing, Honda racing technology parts, 40 amp genuine Nippon Denso alternator, custom Mil-spec jacketed wire loom, 3 gear gearbox for Lycoming style propeller rotation and vertical engine orientation, forged, heat treated and ground helical gears, dual overhead camshafts, original Honda tuned intake system, 2.33/1 gearbox ratio.
Engines with horsepower over 160 hp
For power outputs exceeding 160 hp, Continental Titan and Lycoming Thunderbolt non-certified engines are popular among aircraft builders.
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Continental Titan engines with power ratings from 174 to 195 hp are offered as experimental derivatives of the four-cylinder Lycoming parallel-valve architecture engines in the popular 340 and 370 displacements but with numerous upgrades. For example, Titan sumps/intake manifolds are a magnesium version of the traditional “hot sump” casting, saving a meaningful 7 pounds. There is no forward-facing hot sump or rear-facing sump on Titan engines while they also feature steel insert crankshaft thrust washers. All Titan engines are statically and dynamically balanced, and they also use roller valve lifters. Continental’s nickel-carbide cylinder treatment (NiC3) is offered for a definite upgrade in durability and corrosion resistance allowing for a 5-year warranty against cylinder barrel rusting on all Titan engines along with their normal 2-year or TBO warranty on the rest of the engine assembly. Warranties begin when the engine is put in service, not exceeding one year after purchase. TBO is 2000 or 2400 hours. Finally, the Titan line also offers an extensive line of optional equipment.
LYCOMING non-certified engine solutions for experimental aircraft are also offered and include their standard experimental engine models and their premium Thunderbolt product lines, the company’s brand of high performance, built-to-order powerplants for these aircraft. Instead of being made on an assembly line, each Thunderbolt engine is hand-built. Also, most of these experimental-category engines contain performance-enhancing modifications such as high-compression pistons, cold-air induction, and electronic ignition designed to increase horsepower and flight efficiency. Each LYCOMING Thunderbolt engine is a non-TSO version of a genuine Lycoming engine model, factory built and tested which is further customized & personalized through the selection of several popular options of fuel systems, ignition systems, performance enhancements and finishing options. All Thunderbolt engines feature a balanced rotating system within 0.5 gram (connecting rods, pistons, piston pins), ported and polished cylinders, and customized paint options. Thunderbolt engines are offered in Signature, Extreme or Competition series and cover the full spectrum of Lycoming familiar O-235, 320, 360, 390, 540 and 580 cubic inch models, although the IO-390 and IO-580 are the most popular. Of the engines offered, all use parallel valve cylinders except the 390 and 580, which employ angle-valve cylinder heads. That makes them more efficient and powerful, but also heavier and more expensive.
Of the engines offered, all use parallel valve cylinders except the 390 and 580, which employ angle-valve cylinder heads. That makes them more efficient and powerful, but also heavier and more expensive.
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AC Aero Combined Cycle Technology (CCT) Higgs Diesel engines are offered in different models including:
- the HAWK V4 E330J/G Diesel, a clean sheet combined cycle, spark ignition, multi-fuel engine weighing only 306 lbs. /139 kgs with a power output of 350 hp in naturally aspirated (NA) and up to 500 hp in fuel injection (FI) engine versions,
- the EAGLE V8 E-660J/G (650 hp) and forced induction E-660J/G-T (800 hp) clean sheet design engines,
- the CONDOR V12 E-1000J/G (1000 hp) and forced induction E-1000J/G-T (1600 hp) clean sheet design engines weighing only 664 lbs. (302 kgs).
Other manufacturers, such as Viking or Aero Momentum also offer automobile converted engine models equivalent to or exceeding horsepower and performance characteristics of Continental Titan and Lycoming Thunderbolt engines but significantly lower priced.
Viking 195T Turbo engine is a 1.5 L, direct injected, 4-cylinder turbocharged Honda converted aircraft engine which delivers 195 hp @ 5400 rpm, weighting 260 lbs.
Aero Momentum AM20T 2.0-liter 16V DOHC automotive converted liquid cooled EFI engine delivers 260 hp @ 5800 rpm and is comparable in power and/or weight to Lycoming TIO-360, IO-390, IO-540 and Continental TSIO-360 and IO-520 engines.
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