Rotary (Wankel)

2021 Engine Buyer’s Guide


Aircraft Engine Buyer's Guide 2021

American Rotary Engine

The very definition of an alternative engine. The reality is fully functional Experimental aircraft Wankel rotaries today are the work of two companies: American Rotary Engine and Auto PSRU’s (see next listing). The former builds the engines while the latter makes the propeller gearbox.

American Rotary Engine is the aviation sidebar to Atkins Rotary, a hot rod shop up to its neck in modifying and supporting Mazda Wankels for auto racers. It makes hopped-up parts and adapters for just about anything that moves and a Wankel fits in. As Mazda parts go out of production, American Rotary Engine keeps getting busier producing replacements, including such sophisticated bits as its own, upgraded rotor housing, timing covers and water pump housings.

For aviation, American Rotary Engine concentrates on the Mazda 13B engine. And while American jokes that customers all want a “500-hp engine that weighs 30 pounds,” it offers up to 200-hp, turbo normalized packages. American’s aviation-specific development is a spring-loaded pop-off valve set to 4 pounds to avoid over-boosting after descents or on go-arounds.

Big power from Chevy V-8s is the customer’s demand at AutoPSRU’s. The LS-3 engine is coupled to their SD550 gear reduction unit featuring a centrifugal clutch for reduced starter and other kickback loads.

Auto PSRU’s

Gearbox and engine-package specialist Auto PSRU’s likes to source its Mazda 13B naturally aspirated and turbo normalized engines from American Rotary Engine (see previous listing). Auto PSRU’s long-standing offering is a 200-hp firewall-forward fitment for the RV-7. Curiously, after a six-year drought, interest in Wankels picked up again in 2020, especially in the higher-powered 13B options.

Airshow coverage sponsor:
Engine ModelDrive TypeHorsepowerWeightPrice
American Rotary Engine
2 rotor 13Bgeared180 hp @ 6000 rpm320 lb wet w/ alternator, starter, ECU, EFI and EI$20,000
Mazda 13Bgeared180 hp @ 7600 rpm (centrifugal clutch) 2.778:1 ratio385 lb installed, typical, complete$34,100 FF
Mazda 13B Turbo Normalizedgeared200 hp @ 7600 rpm (centrifugal clutch) 2.778:1 ratio410 lb installed, typical, complete$42,700 FF


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