Hello Paul, what can you tell us about this old company,

Duncan Aviation(Comanche, Okla.) many years ago listed in their brochure a direct-drive single rotor Mazda RX-7 bridge-port aircraft engine. They machined the crank to accept a new main-bearing located on the front of the engine. The main-bearing was housed in an easily-machined circular housing. Propeller-boss was attached to the front of the re-machined crank.

Engine was rev-limited to 60hp at 4000 rpm. Engine could be fitted with a fixed-pitch prop, or cockpit-controlled variable-pitch prop( Warpdrive props makes a carbon-fibre one, and their website has a good tip-speed calculator). Duncan photo of this single-rotor engine shows it fitted with a 2-blade in-flight adjustable prop.

Thanks,

Steve Carlisle

I got the impression he was a scam artist. Something about him moving to Mexico
to avoid shipping product after accepting payment I think. Not sure. Long time
ago. Perhaps he was just technically incompetent.

Technically speaking 4000 RPM is not very useful for a direct drive aircraft engine.
The prop diameter needs to go way down to achieve 4000 RPM so the
prop is very inefficient.

Also a one rotor with cast iron end housing would be rather heavy for only 60 HP.

A one rotor with cast iron end housing with 100 HP is rather heavy. Especially when
one adds the gear box weight. The only reason people build bridge ports is p-ports
are out lawed in certain SCCA class's. That makes bridge ports irrelevant for aircraft use.

The only Mazda based one rotor that makes sense for aircraft use  is a p-ported  all
aluminum one rotor with a gear box.

Paul Lamar

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