2021 Engine Buyer’s Guide


Aircraft Engine Buyer's Guide 2021

Azalea Aviation, LLC

Bill Clapp is a busy man, what with running a fixed-base operator (FBO) terminal, flight school, Saberwing aircraft and the Spyder Corvair engines. So we understand when Clapp says for 2021 there are no technical or price changes for his two-engine line of Corvair-based engines.

The naturally aspirated 100-hp unit is built from reconditioned GM parts reinforced by a steel front hub on the crankshaft, an added front main bearing, nitriding, a 30-amp rear-mounted alternator and plenty of new service parts. The 125-hp version gets its oomph from a brand-new, counterweighted, quarter-inch stroker crankshaft that takes it out to 3.1-liters displacement. This is without having to cut the case for overly large cylinders, thus preserving case integrity.

All Spyder Corvair engines are built to order, so a bit of lead time is expected. While waiting, customers can review a multitude of Corvair teardown, operation and other manuals on Clapp’s Azalea Aviation website. Locals and those willing to travel can also take advantage of builder-assist and tutorial programs Clapp puts on at his home base in Cook County, Georgia—pandemic allowing. Yet more Corvair support comes via cowlings, spinners, props and so on for Zenith and Sonex airframes, among other applications.

Not unexpectedly for a high-energy fellow, Clapp is working on multiple new projects. In the works is a turbo package that will likely be fuel injected with a constant-speed prop. Look for it in 2022 or so. Even further out could be a Saberwing twin, which is driving its own set of engine support pieces. So, it seems there is still plenty of life behind the Corvair engine.

Corvair flat-sixes offer an easy displacement increase over VW-based engines and are cost-competitive on a dollar-per-horsepower basis. They’re found in everything from Pietenpols to sleek Panthers and enjoy good support.

Sport Performance Aviation, LLC

Dan and Rachel Weseman own Sport Performance Aviation, maker of the Panther sport plane powered by Corvair engines. From the beginning, the Wesemans partnered with Corvair überguru William Wynne for their engine needs. They also functioned as distributors of Wynne’s engines for a couple of years while Wynne attended to other interests.

When Wynne returned to Corvairs full-time in 2020, Sport Performance Aviation happily returned all engine business to Wynne, save for offering the highly modified 3.0- and 3.3-liter unassembled Corvair kits. The 125-hp 3.0 uses big-bore cylinders on a set of bored-out heads and case, while the 125-plus-hp 3.3 adds a billet crankshaft to the big-bore kit. These are premium, higher-powered engines selling for more than the standard displacement engines from Wynne, but just the thing for hot rod sportsters.

Fly Corvair

William Wynne is the outspoken force at Fly Corvair, where he’s been building aviation Corvair engines for 34 years. His engine line begins with an economy-minded 100-hp 2700cc model, then moves to a 110-hp 2775cc upgrade and in practical terms tops out with the 110-hp 2850cc variant. The latter is a favorite, offering a good combination of power and economy.

Asked about pricing, Wynne says all his engines are $9500 because that’s the basic price of all of them, with every customer specifying whatever extras they might want. Wynne also builds the 3.0- and 3.3-liter Corvairs offered as engine kits by Sport Performance Aviation (see previous listing).

Aside from these well-developed engines, Wynne is the source of engine manuals, supporting pieces such as intake and exhaust manifolds, cowling parts and propellers, plus a surprising number of educational seminars. He also offers engine building and overhaul services, along with considerable support to the builder community.

Engine ModelDrive TypeHorsepowerWeightPrice
Azalea Aviation
Spyder 100direct100 hp210-215 lb wet with alternator$10,500
Spyder 125direct120 hp210-215 lb wet with alternator$12,900
Sport Performance Aviation LLC
3000cc (183ci)
direct120 hp @ 3300 rpm225 lb w/ starter, ignition, and alternator$13,495
3300cc (201ci)
direct119 hp @ 2800/125 hp @3300 rpm225 lb w/ starter, ignition, and alternator$16,395
Fly Corvair
2700cc (165ci)
direct100 hp @ 3000 rpm225 lb w/ starter, ignition, and alternator$9500
+ options
2775cc (169ci)
direct105 hp @ 3000 rpm225 lb w/ starter, ignition, and alternator$9500
+ options
2850cc (174ci)
direct110 hp @ 3000 rpm225 lb w/ starter, ignition, and alternator$9500
+ options
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Tom Wilson
Pumping avgas and waxing flight school airplanes got Tom into general aviation in 1973, but the lure of racing cars and motorcycles sent him down a motor journalism career heavy on engines and racing. Today he still writes for peanuts and flies for fun.



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