For recreational aviation, you want a good lightweight engine that gives you power without taking away too much of the weight available on the frame of your aircraft.
For this reason, two-stroke engines are widely used in recreational planes. These engines are lightweight, durable, provide power, and are inexpensive.
The best two-stroke engine for recreational aircraft is the Rotax 503 engine.
The 503 engine from Rotax has enjoyed 25 years of popularity with part time aviators. While the company has recently discontinued the engine, it is still widely used in the field.
A more expensive, more powerful engine could certainly be purchased for your recreational plane, but there isn’t a need.
You’ll also find that these higher end engines don’t last as long as the Rotax 503 engine. This is because those higher end engines are designed to have a lot of hours put on them in a short time.
If you don’t fly very often, the engine will stop working due to age long before you hit the maximum hours it is supposed to be able to handle.
By contrast, the Rotax 503 is designed for long term durability with fewer hours put on in a longer amount of time.
This means that the chances you will have to repair or replace your engine with limited use much lower than with a more expensive and powerful engine.
The Rotax 503 engine gives you a lot of RPMs, but little torque. This is perfectly fine for small recreational aircraft. It means that you will have the power you need to get off the ground and keep pushing forward through the air.
It does mean, however, that you will need a proper system that works without the added torque. Still, this engine gives you more than enough power to get the job done.
When you have a small recreational plane that has a light frame, you are limited in how much weight the frame can handle.
If you have a 500-pound weight limit on your frame and your engine weighs more than 25 pounds, you may be compromising your ability to take a passenger.
The Rotax 503 engine is lightweight, and won’t take much away from your load capacity.
Even though they have been discontinued, you can still find Rotax 503 engines quickly. They are available online and in aviation outlets.
If you have trouble finding the 503, you can find similar Rotax models such as the Rotax 447 for sale. Rotax 447 comes with the same specifications as the 503 engine.
These have also been discontinued, but are similar to the 503 and with more limited use they can sometimes be found more quickly.
You will start having trouble finding parts for these engines shortly, within a few years. If you do purchase a Rotax 503 or 447, make sure you also buy special pistons and a crankshaft to put aside for your next overhaul.
Otherwise, you will find yourself buying another engine if that one needs repairs, so I hope you now know what to do.