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-   -   Weight difference: alum vs comp props (https://vansairforce.net/community/showthread.php?t=148778)

SabreFlyr 04-19-2017 09:11 AM

Weight difference: alum vs comp props
 
Planning on using the Hartzell blended airfoil 74" aluminum prop on my -14. However, I would like to consider a composite prop but want to make sure that I don't create a CG problem. Where can can I find the weights of the aluminum Hartzell and the Whirlwind and Hartzell composite props? I'm planning on moving the ELT to just behind the aft baggage bulkhead but not sure how much more I'd have to move (or what) to maintain the same CG. I seriously doubt the ELT move will come close to matching the CG shift caused by the prop change.

Nova RV 04-19-2017 09:14 AM

I think the aluminum Hartzell vs the Whirlwind is something like 55 vs 42 lbs. I know there are a few 14s out there already flying with the composite Hartzell and Whirlwind props.

Lamepilot 04-21-2017 09:08 PM

Props
 
We love our Hartzell composite prop, and I have flown many other ones before we decided on it. It is very smooth, the climb is fantastic and the CG could not have worked out any better if we planned it. The spinner that you need for it is beautiful, long and sleek. The only downside I can think of is the cost. You get what you pay for. Buy it, you will be pleased. Good Luck

olyolson 04-22-2017 07:09 AM

Prop weights
 
Ray,

I have been exchanging e-mails with Matt Van Voorhis at Hartzell about prop weights. Here is some info I received recently from him in an e-mail:

"The most common 2 blade blended airfoil prop is the F7497 blade model. That propeller weighs about 58 pounds. The most common Van's composite propeller would be either the N7605 blade or the NC8301 blade. Those propellers weigh 43 and 41 pounds respectively."

Matt's e-mail is: mvanvoorhis@hartzellprop.com

SabreFlyr 04-22-2017 07:27 AM

Carl, Oly, thanks for the information. Very useful in my planning.

Carl, you mentioned the spinner. I found it curious that the second-hand QB kit that I bought included a spinner but I didn't ask about it. I would have presumed that would have come with the firewall forward kit. I only have empennage, wings and tail. Did you buy your spinner from Hartzell?

RV6_flyer 04-22-2017 09:48 AM

Quote:

Originally Posted by olyolson (Post 1167477)
Ray,

I have been exchanging e-mails with Matt Van Voorhis at Hartzell about prop weights. Here is some info I received recently from him in an e-mail:

"The most common 2 blade blended airfoil prop is the F7497 blade model. That propeller weighs about 58 pounds. The most common Van's composite propeller would be either the N7605 blade or the NC8301 blade. Those propellers weigh 43 and 41 pounds respectively."

Matt's e-mail is: mvanvoorhis@hartzellprop.com

What concerns me other than PRICE on the Hartzell composite prop is that Van's website says "Extended hub composite 2-blade".

It they mean extended hub like the old Twin Comanche, that would be a deal breaker for me. If it is the hub that works on Van's standard cowl, then that works for me.

Av8rRob 04-22-2017 10:37 AM

Carl, on your great website you have your w&b posted prior to paint. Any chance you can update us on what you paint job has done to the cg and weight of your plane?

Thanks

SabreFlyr 04-22-2017 11:04 AM

Quote:

Originally Posted by RV6_flyer (Post 1167493)
What concerns me other than PRICE on the Hartzell composite prop is that Van's website says "Extended hub composite 2-blade".

Thanks for pointing that out, Gary. Definitely needs to be checked out.

RV6_flyer 04-22-2017 11:41 AM

Quote:

Originally Posted by SabreFlyr (Post 1167502)
Thanks for pointing that out, Gary. Definitely needs to be checked out.

Ray:

I did email Matt to ask about the extended hub. Will report back if I learn anything.

It appears that the hub listed on Van's website has the same Type Certificate Data Sheet. P-920.

The confusing part is that C in the hub model: "Identifies basic design ? C denotes no integral shaft extension" on the above linked TCDS.

That is why I emailed Matt to learn more.

MED 04-22-2017 02:29 PM

I am currently planning to follow Carl and Rafael's lead with the Hartzell composite prop. What is the concern about the extended shaft? Doesn't a Twin Oomanche have O-320 engines?


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