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Propeller Challenge – Calling Jan Carlsson

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addaon

Well-Known Member
Supporting Member
Joined
Feb 24, 2008
Messages
3,976
Location
Kanab, UT
Jan, this is somewhat inspired by the "quiet props" thread, but also just a pragmatic question.

The HKS 700T engine is an 80 hp turbocharged engine (77 hp continuous) that produces peak power at 5300 rpm (4900 rpm continuous), and has an integrated 2.62:1 redrive, for a prop speed of ~2025 rpm (1870 rpm continuous).

The Sonex Onex is designed around the Aerovee engine, which produces its 80 hp at 3400 rpm, direct drive. It spins a 54" x 44" fixed-pitch propeller, giving a ground clearance of 8" (both taildragger and tricycle).

To stay within the 7" ground clearance requirement for a tricycle gear aircraft prescribed in Part 23, and assuming a similar thrust line between the HKS and Aerovee, the maximum prop diameter for the Onex would be 56". This leads to an HKS tip speed of 150 m/s (~0.44 Mach), which is, as expected, incredibly slow.

So, what does an HKS-driven Onex look like? Lots of blades, I assume. Noise level? Efficiency?
 
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