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Propeller choice

Scott Hersha

Well Known Member
I'm ready to order a prop for my new RV8, and have decided to get the Hartzell blended airfoil C2YR-1BFP. The question I have for those with experience - is there any advantage/disadvantage of a 74" v.s. 72"? Vans website recommends the 72" for a taildragger RV8 for ground clearance, but I know several people running 74" Hartzells, both metal and the newer composite, and loosing 1" of ground clearance doesn't seem to be a concern. The 74" will weigh a little more, but is there a performance advantage? Does anybody here have any real comparative data? I have a Superior IO-360-M1B with 9:1 pistons-about 190hp.

Thanks
 
I struggled with this decision on my new RV-8 project as years ago I replaced a FP prop with the 74? BA prop on my RV-8A and wanted that same performace. After taking to people who know of this, I went with the 74?. My take is it seems the 74? is more popular for the RV-8 than the 72?. I wanted the longer blade as everything I read on props told me the longer blade would be more efficient (within reason of course).

Also tilting the scale was recent flight time in an RV-8 with a 76? prop. Measuring the tip to ground clearance, it still had more clearance than the Van?s recommended prop for the RV-10 (I note that RV-10 is a nose dragger - I get that).

If I routinely flew in and out of rough grass stripes I might want the 72? as you can hit a bump. I have no concern with the 74? blade on average grass strips. Considering I have been to a grass strip exactly twice in the last decade means (for me) this is not an issue.

Carl
 
Prop length for tail draggers

I've wondered about Van's recommendations for the TD vs training wheel airplanes for several years. Recently, a colleague (ATP, with considerable experience in everything) had a prop strike and expensive teardown on his -6.

Seems he bounced a little on landing and tried to recover. On the second touchdown, the gear squatted and the prop hit the runway.

I'm told that the -8 gear is enough stiffer than the -6 that this won't happen, but it might explain the recommendation.
 
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