Engine

The engine selection for our SportCruiser is not really a selection, as the corresponding hardware (engine mount, cowling) is currently only available for the Rotax 912. Non the less I had a look at the various types of engines before ordering the airframe kit, as I did not want to end up having to use an engine I am not happy with.

The engines I had a serious look at were the following:

Rotax 912 S / ULS

The Rotax 912 ULS is the engine I will finally end up with. It is the de-facto standard in today's 100 hp range kitplanes. Rotax has sold 125'000 aircraft engines, 18'000 of which are from the 912 family. They deliver engines in both certified and uncertified versions, which means they are not just an "experimental" company but are selling to manufacturers of certified aircraft, with their much higher requirements. Rotax is also producing engines for other uses, like for motorcycles, skidoos, small all terrain vehicles etc.

The Rotax 912 ULS is a 1352 cm³ water/air-cooled, horizontally opposed, four cylinder, naturally aspirated, carburated, reduction gear equipped engine that produces a maximum of 100 hp at 5800 rpm.

The Rotax differs from traditional aircraft engines by using water cooling and by running at a higher rpm than the propeller, thus requiring a reduction gear. At max engine rpm the propeller will turn with 2400 rpm, which is lower than with most other engines, and much lower than with the Jabiru.

We have a number of Rotax equipped planes at our airport, and from the feedback I hear the users are happy with them. In addition they are very quiet, which is a big argument today.

Cessna considered installing the Rotax 912 in their new LSA, but finally went for the Continental O-200 (see below). The fact that they used the Rotax 912 in their prototype non the less shows that even a company like Cessna considers the Rotax a viable alternative to their traditional suppliers.

The October edition of the AeroRevue, the Swiss Aero Club's monthly magazine, contains an article about the pollution produced by different aircraft engines. According to that article a Thielert Diesel produces about 100 times less pollution than a traditional Continental or Lycoming engine, the Rotax 912 more than 10 times less.

Jabiru 3300

The Jabiru 3300 is of a classical air cooled, horizontally opposed, 4 stroke, direct drive design. Different models with different numbers of cylinders are available, with the 6 cylinder 3300 (3300 cm³) with 120 hp the appropriate choice for a kitplane like the SportCruiser. The 2200 with 80 hp is a bit underpowered, in addition the engine runs at a relatively high rpm at full power (3300 rpm for both types). This will either lead to a relatively high noise level (which is a big issue for certification in Switzerland), or require operation below max RPM, meaning also below max power.

I do not know anybody who operates a Jabiru, so all information I have is from Internet forums. As that kind of information is often unreliable I won't repeat any of it here.

Teledyne Continental O-200

The O-200 is the classical low power engine that has been used in many planes like Piper Cub's, Cessna 150's etc. It is a development of the C90, which is a development of the A-65, which dates from 1939. This explains why it is very traditional, if not old fashioned.

The O-200 is a 3200 cm³ air-cooled, horizontally opposed, four cylinder, naturally aspirated, carburated, direct drive engine that produces a maximum of 100 hp at 2750 RPM.

Cessna is installing the newest version of the O-200, the O-200D in their SkyCatcher. Apart of some weight reduction measures this seems however to be the same engine.

Other engines

Of course I had a look at many more engines, here some that might be considered for future projects:

PBS TJ 100 C

A small turbojet from PBS with 110 kg of thrust, which has been tested on a Blanik glider. If I would add two of them in underwing pods on the SportCruiser, I would get a small version of the Me 262.

Hog-Air

Hog-Air is producing conversions of Harley-Davidson motorcycle engines for light aircraft. If you want an LSA with a warbird sound, that's the way to go. I saw that one on a Zenith in Oshkosh in 2004, but I haven't found any recent information about the company on the web.

Rotec Radial

Rotec has developed small radial engines for homebuilts. If you want a SportCruiser with a retro look that might be an alternative.

Innodyn 165TE

Whow. A Piper Super Cub with a propeller turbine. I have seen it in 2004 in Oshkosh. They will probably call it the Super Duper Cub. The company producing it is called Innodyn. The turbine is available in versions from 165 to 255 hp, so whoever is not happy with the cruise performance can just scale up a little. On the web page of Innodyn they have some videos of a Vans RV-4 as well as of the Super Cub. I am sure it would look great on the SportCruiser.