Model Airplane Engines: Glow, Gas, Electric and Turbine
Model airplanes are powered by four kinds of engines: glow engines (methanol-based fuel with nitromethane, ignited by a glow plug; sizes like .46 or .91 cubic inches), petrol “gas” engines (spark ignition on unleaded petrol mixed with two-stroke oil; 10–250 cc), electric brushless motors with LiPo batteries, and miniature turbines on kerosene for jets. Electric is the default today; glow and gas remain popular for sound, long flights and large models. Here’s how each works, typical sizes and brands, and how to choose.
By Kyle HilsonUpdated: October 20264 min read
The four engine types
| Type | Fuel / energy | Typical sizes | Pros | Cons |
|---|---|---|---|---|
| Glow 2-stroke | Methanol + nitromethane + oil | .10–.91 cu in (1.6–15 cc) | High power for weight, simple | Oily exhaust residue, fuel cost, noise |
| Glow 4-stroke | Same glow fuel | .40–1.80 cu in and more | Scale sound, efficient, big props | Heavier, more complex, valve adjustment |
| Petrol (gas) 2-stroke | Unleaded petrol + 2-stroke oil | 10–250 cc | Cheap fuel, long runs, reliable | Heavy; needs ignition battery; vibration |
| Electric brushless | LiPo battery | Watts instead of cc | Clean, quiet, instant start, easy | Short flights, battery cost and care |
| Turbine | Kerosene (Jet A-1) + oil | Rated by thrust (kg/N) | Jet sound and speed | Expensive, waivers, fire risk |
Engine size vs plane size
| Plane | Glow | Petrol | Electric equivalent |
|---|---|---|---|
| 40-size trainer (about 1.5 m span) | .40–.46 2-stroke | – | about 600–800 W, 4S |
| 60-size sport (about 1.6–1.8 m) | .60–.91 2-stroke, .91 4-stroke | 15–20 cc | about 1000–1500 W, 5–6S |
| 30 % aerobatic (about 2.2 m) | – | 50–60 cc | about 2500–3500 W, 10–12S |
| 35–40 % aerobatic (2.6–3.4 m) | – | 100–170 cc | Large 12S+ setups (rare) |
| Scale jets | – | – | EDF; turbines for large jets |
Typical pairings; the kit manufacturer’s recommendation always comes first. Sizing electric power systems is explained in how to size an electric motor.
Well-known engine makers
- Glow: O.S. Engines (2- and 4-stroke), Saito (4-stroke), Evolution, ASP/Magnum.
- Petrol: DLE, DA (Desert Aircraft), 3W, Evolution gas, NGH, and converted Zenoah-based engines.
- Turbines: JetCat, Kingtech, Xicoy, Behotec, Jetcentral.
- Electric: many brands of outrunners matched by kV, size and watts.
Fuel: can a model engine run on regular unleaded?
Petrol model engines, yes: they run on regular unleaded petrol mixed with a quality two-stroke oil, commonly around 40:1 to 50:1 (follow the engine manual, which may ask for a richer mix during break-in). Glow engines, no: they need glow fuel with methanol, typically 10–15 % nitromethane and castor or synthetic oil. Some glow engines can be converted to petrol with a spark-ignition kit, but that’s a project in itself. More on petrol engines: gas engines for RC planes.
Which engine type should you choose?
| You want… | Choose |
|---|---|
| Easiest start, small to medium planes | Electric |
| Sound and the classic experience on a sport plane | Glow 4-stroke |
| Large aerobatic or scale planes with long flights | Petrol |
| Jets with real jet sound | Turbine (after experience with EDFs) |
Engine care basics
- Break in new engines per the manual (often rich runs on the ground or in gentle flights).
- Use the propeller sizes listed for the engine and balance them.
- Glow: run the engine dry at the end of the day and use after-run oil.
- Petrol: check ignition wiring and the kill switch; keep the ignition battery charged.
- Mount engines on a solid firewall with correct thrust angles; check screws for vibration loosening.
FAQ
What powers model jet airplanes?
Small and foam jets use electric ducted fans; large scale jets use model turbines running on kerosene.
What does .46 mean on a glow engine?
Displacement in cubic inches: .46 cu in is about 7.5 cc.
Are gas or glow engines better?
Petrol for large planes (cheap fuel, long runs); glow for smaller sport planes. Electric beats both for convenience.
Who makes the best model airplane engines?
O.S. and Saito are classic glow names; DLE and DA lead in petrol; JetCat and Kingtech in turbines.
More on this topic: the complete RC Airplanes guide covers the basics behind this article.
About 20 years in RC. Mostly boats in the NAVIGA Mini Eco Expert class, with many self-made parts; also a King Motor Baja 5B, a home-built electric plane, home-built nitro planes he has flown, and an RC helicopter. More about SwellRC
