New Hartzell Prop STC

[EricJ]

3 minutes ago, MikeOH said:

How does one deal with nicks, and such, in a carbon fiber prop?  I wouldn't think filing the edge is an approved method

Same as other composite props, like MT or wood or whatever.   They usually have a leading edge that is nickel or stainless or something.

[TheMooneyAnomaly]

22 hours ago, MikeOH said:

Can you verify the price is nearly $25,000?

I believe that is about correct.

[TheMooneyAnomaly]

21 hours ago, EricJ said:

There's not a lot more efficiency that can be squeezed out of modern propeller designs, so most of the innovations now are on reducing weight and reducing noise.   Don't expect anything to give you a significant increase in speed without somehow putting more power into it.

Well put.  Prop airfoil designs have been mighty efficient for a while. I have some adjustments to make before flying the test profiles again to have solid numbers to share.

[TaildraggerPilot]

25 Large for a two blade Mooney prop. Nah…..

[TheMooneyAnomaly]

On 7/3/2025 at 1:01 PM, ProtoFly said:

No biggie.  Just remove the Gill/Concorde Lead-acid battery and replace with an EarthX.  Between the prop and the battery, you'd pick up somewhere near 40 lbs useful load....

I transitioned to an EarthX in the rear empennage in anticipation of this change.  I would still like to move more weight forward and am interested in finding details on moving the battery to the avionics compartment.

[MikeOH]

18 minutes ago, EricJ said:

Same as other composite props, like MT or wood or whatever.   They usually have a leading edge that is nickel or stainless or something.

So, on the rare instance of damage to the face of the blade, the prop is trashed?  Or, is there an approved repair process?

[EricJ]

32 minutes ago, MikeOH said:

So, on the rare instance of damage to the face of the blade, the prop is trashed?  Or, is there an approved repair process?

Those are the details you learn in the manuals for the individual props.   Most composites have repair methods and repair limits.   Metal props do, too.

[MikeOH]

4 minutes ago, EricJ said:

Those are the details you learn in the manuals for the individual props.   Most composites have repair methods and repair limits.   Metal props do, too.

OK.  My question was based on thinking once the composite fibers were compromised (i.e. shredded) the integrity of the blade was destroyed.  Glad to hear there is some method to 'patch' a hole in the blade of a composite prop.

[StevenL757]

26 minutes ago, MikeOH said:

OK.  My question was based on thinking once the composite fibers were compromised (i.e. shredded) the integrity of the blade was destroyed.  Glad to hear there is some method to 'patch' a hole in the blade of a composite prop.

From the former head of Hartzell's Top Prop division - repair instances are unlimited, versus their life-limited metal counterparts.  In other words, there's only so much you can grind away from a metal prop before it's no longer serviceable.  Composite props are able to be machined and repaired to new standards over and over...essentially yielding a new prop with each successive repair.  Largely, for this reason, the $24k+ price is what it is.

[jetdriven]

5 hours ago, TheMooneyAnomaly said:

I transitioned to an EarthX in the rear empennage in anticipation of this change.  I would still like to move more weight forward and am interested in finding details on moving the battery to the avionics compartment.

So have you seen any increase in cruise speed or other performance with this prop? And were you compensated in any way or given a discount on this propeller to market it?

[Aerodon]

17 hours ago, StevenL757 said:

From the former head of Hartzell's Top Prop division - repair instances are unlimited, versus their life-limited metal counterparts.  In other words, there's only so much you can grind away from a metal prop before it's no longer serviceable.  Composite props are able to be machined and repaired to new standards over and over...essentially yielding a new prop with each successive repair.  Largely, for this reason, the $24k+ price is what it is.

MT  Propeller bragged about this too, but it turns out that their props are infinitely repairable as long as you bring infinite amounts of money to completely replace anything that might look like it is thinking of wearing out.

Aerodon

 

[jetdriven]

Yup it’s like George Washington’s axe. Replaced the blades twice and the hub once.  Still has 4000 hours since new.  

[Pinecone]

On 7/4/2025 at 10:31 AM, jetdriven said:

Not to mention the amp-hour capacity is half that of the standard rg35 battery.  

And they were on MS for a while and a number of us asked form them to make a bigger one. Double amp hours and still a good bit lighter.  But their answer was they knew better than us. 

Hmm Potential customers say make X and I will but it and they say nope you don’t know what you want.  Dumb

[PeterRus]

1 hour ago, Pinecone said:

And they were on MS for a while and a number of us asked form them to make a bigger one. Double amp hours and still a good bit lighter.  But their answer was they knew better than us. 

Hmm Potential customers say make X and I will but it and they say nope you don’t know what you want.  Dumb

To double amps just put two of these in parallel. 

[jetdriven]

49 minutes ago, PeterRus said:

To double amps just put two of these in parallel. 

STC doesn’t allow for that. 

[Hank]

58 minutes ago, PeterRus said:

To double amps just put two of these in parallel. 

 

8 minutes ago, jetdriven said:

STC doesn’t allow for that. 

And there's no physical space in my Mooney for another battery on my firewall.