version with two carburetors on each bank. Strangely, these engines will develop less horsepower than the 110 hp engines at the rpm needed for a direct drive propeller. GM made a few Turbo charged Corvair engines rated at either 150 or 180 hp. They had different cam, heads, distributor and induction systems but they had the same crankshaft, connecting rods, pistons and cylinders as the 110 hp engines. Even though the last Corvair engines were made 35 years ago, about 1,700,000 of them were built and they are still quite easy to find. It is interesting to note that Lycoming has taken 50 years to produce 230,000 aircraft engines.
There are several myths about the Corvair. The engine is said to be a terrible oil leaker. That was true of the engines built by GM but when assembled with care and with modern O-rings and gaskets they are no worse than a regular aircraft engine. Some say it was General Motors’ answer to the VW but they had very different design goals. The VW was designed to be the cheapest car possible. The Corvair was an attempt to produce a small sporty car with the quality of the larger GM offerings. All Corvair engines have hydraulic lifters, six cylinders and oil filters. Most VWs did not have these features. And lastly, Ralph Nader did not kill the Corvair. By 1969 the Corvair sold for about the same price as the Nova but cost more to make so GM killed it for simple economic reasons.
So what does "conversion" mean? It is not a big deal to someone who can build an airframe and that is Wynne’s goal, to make it possible to get a good 100 hp engine that will be sufficiently reliable for a fun airplane that is used for day VFR, non-aerobatic flight and not cost so much as other engines. It also presents the opportunity to learn a lot about engines. When modified as Wynne directs, you end up with an engine about the size of a Jabiru 3300, (28 inches long and 28.5 inches wide). It will put out 100 hp at 3200 rpm and 90 hp continuous at 2800 rpm. The most powerful Corvair auto engines produced 180 hp at 5500 rpm so asking it to produce 90 hp at 2800 rpm is conservative. The prop will turn backwards by American standards (unless you buy a special cam and make a few other changes). It will have a standard SAE #1 prop flange and use a wood or Warp Drive prop of about 68 inch length. It will use any of a variety of standard aircraft carburetors or the Aero-Carb and can be set up for gravity feed or use a fuel pump. It will have an electric starter and a small alternator and when so equipped it will weigh 225 pounds. The distributor will be extensively modified and have two sets of points, either of which will run the engine. It will not have fully redundant dual ignition systems. It will have dual coils and points which have given good dependable service. It will have 9:1 compression and use 100 LL fuel. It will look like this.
