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3 blade Hartzell in an RV8 with 0-360 A1A

raisbeck

Member
I've got the opportunity to buy a 3-blade Hartzell (C3YR-1RF) for the RV8 we're building. We've already purchased an Aerosport 0-360 A1A for the project, and I'm wondering if anyone else has tried such a combination.

In particular:
What about the effect on CG? I know that constant speed props tend to make some 8's a little nose heavy, and this is about 14 lbs heavier yet. We're still finishing the fuselage, so I don't have any guess where the CG is going to finally fall.
Are there any harmonic problems with this combination? Again, all I have is second or third hand anecdotal information about substituting 3 blades for 2 on other airframes and engines. FWIW - the prop was recently removed from an -8, and the combination is apparently approved on the Mooney M-20C.


Any first hand experience would be welcome.
 
I'm no expert and am sure someone will chime in with more tech stuff but one often hears 2 Blades are more efficient & of course cheaper to overhaul. The extra weight is obviously a concern as weight is the enemy of any aircraft especially a Vans if being used for Aero's. My 8 has the std IO360 CS & it's a sweet time tested proven combo.
About the only good thing I've heard about 3Blade is they are mostly smoother & look oh so sexy, if it's looks then 4 blade sounds about right:)
Looking fwd to hearing what the more experienced Vans drivers have to say:)
 
3 blades sound much better! :cool:

But - as mentioned, they're heavier, more expensive to overhaul. The weight and larger spinning mass would be a concern to me, personally.

As for harmonics as related to that specific prop and engine combo, that's way beyond trusting an answer on an internet discussion board. Get the TCDS for the prop and examine. Then call Hartzell and discuss. They are, or used to be, very helpful discussing this issue.
 
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I guess at the end of the day look at what everyone else is doing, most Vans are 2 blades & popularity in numbers must mean something:)
 
1 more thing

the only other thing to consider is that 3 blade is harder to get cowl on and off. But there are folks doing it.
 
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