NMPRA

Being I can use a 9x6 prop for 424E ,can I use it in EF1?

Kevin,

The 2022-2023 rulebook clearly states, that for the AMA 427 class, the only prop allowed is the 8x8e.

e. Propeller
Propeller shall be the APC 8 x 8 Thin Electric Propeller, part number
LP08080E. The propeller shall be used in stock configuration except that
it may be balanced be by removing material from the face of the heavy
blade. Any twisting, bending or tampering of the stock propeller is
prohibited and will not be allowed.

Trey

This should have been the prop from day 1, Longer blade is great for takeoffs and the first turn

Probably lower torque effect too?

I hope you bring a lot of spare props. A 9" prop would be problematic with the current configuration on our planes. I'll try them next time I'm out compared to the current 8x8 I suspect DK already tried them out in his extensive testing.
Sparky

If I read correctly, for 424 electric, the prop is a 9X6E prop, not standard 9X6 nitro prop. I may have read that wrong, but I'm pretty sure there was an "E" at the end of the prop designation, just like for the 8X8E prop we use for EF1. Having said that, since they hand out props for both 424 and EF1, I would assume that at the races, the CD will need to be sure they are stocked with 9X6E props as well as the 9X6 nitro and 8X8E props.

edit: Just looked up the 424 Electric provisional rules and here is what it says for propellers:

b. Propeller
1) Material APC composite or a similar, commercially available composite.
2) Dimensions Minimum diameter nine (9) inches. Nominal pitch six (6) inches, as indicated by the manufacturer’s stamp or packaging.
a. IC propeller: LP09060 (9X6)
b. Electric propeller: LP09060E (9X6E)


Bob

Bob,

Yes, the "e" version of the 9x6 APC prop is the one called out for 424e.

As for the handing out of props, it is up to the CD to make that desicion to provide/not provide props for 424, 424e and 427/EF1. At the Nationals, I will provide the props. At my races at OJA, I allow pilots to use their own props.

Trey