NAMBA October 2020 Web.pub
The Nitro Engine – Part 5 (Continued from page 8) PROPWASH 8 October 2020 “Propeller’s by Chris Hoffmann” Complete Propeller Service Sharpening, Balancing, and Modifying All Props in Stock! ABC — PropShop — Octura ABC and PropShop Dealer Nine Time NAMBA SAW Record Holder www.dasboata.com Contact Chris at dasboata@aol.com The best modern designs have a boost port about 11% of the bore wide with around a 55 to 60 degree up angle, a wide rear pair of transfers with about a 5 to 10 degree up angle and narrower front transfers with about a 24 to 28 degree up angle. The modern transfer port roof angles are more like 25/10/55. If you are after mid-range power, the ports should open around 125/128/129 degrees before bottom dead cen- ter of the front, rear, and boost ports respectively. The horizontal angles are as below. Note the hook in the rear transfer.
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