Prop Restrictions with Mag/Pmag

[Brantel]

I am soon going to be installing a Hartzell C2YR-1BF/F74972 and I contacted Les
@ Hartzell to talk about any restrictions that may apply to my setup.

I have a carbed 180hp O-360 with a Mag/Pmag. The Pmag is set to run on the B curve.

Les mentioned that the C2YR-1BF/F74972 does not have any restrictions on an 180hp O-360 with Mags and I got the default answer that they have not tested the prop with Pmags or other electronic ignitions that have timing advance and therefore he recommend that I follow the 200hp restrictions.

Here are the 200hp restrictions:
"Continuous operation is prohibited above 24? manifold pressure between 2350-2550 RPM."

My questions...

Does anyone have a similar setup and if so what if any restrictions do you limit your aircraft to?

Is the 200hp restriction above really an issue in normal use with an RV7?

Do you have any other comments regarding this topic that would be good to know/consider?

[Sig600]

Opted for the Whirlwind for this very reason.

The only question is 200RV or the new one?

[DanH]

Originally Posted by Brantel

Do you have any other comments regarding this topic that would be good to know/consider?

Les has measured stress data from formal vibration surveys to guide his opinion, so I'd take the recommendation seriously. The prohibited power settings don't seem like something you would really miss anyway.

Originally Posted by Sig600

Opted for the Whirlwind for this very reason.

Because you can describe the blade modes?

[Sig600]

Originally Posted by DanH

Les has measured stress data from formal vibration surveys to guide his opinion, so I'd take the recommendation seriously. The prohibited power settings don't seem like something you would really miss anyway.



Because you can describe the blade modes?

Because of Hartzells operating restrictions that WW does not have, and the performance.

[PCHunt]

IINM, (if I'm not mistaken), the aluminum blades of the Hartzell are subject to harmonic vibration and the resultant fatigue, whereas the composite blades of the Whirlwind are not.

Correct me if I am wrong on this.

[rzbill]

Originally Posted by PCHunt

IINM, (if I'm not mistaken), the aluminum blades of the Hartzell are subject to harmonic vibration and the resultant fatigue, whereas the composite blades of the Whirlwind are not.

Correct me if I am wrong on this.

Does anybody have any evidence that whirlwind has actually instrumented and tested their props as hartzell does? For me, the lack of this and the early hub problems took whirlwind off the list at the time I needed to make the choice. Lack of testing does not mean a product is automatically better.

[Captain_John]

Originally Posted by rzbill

Does anybody have any evidence that whirlwind has actually instrumented and tested their props as hartzell does? For me, the lack of this and the early hub problems took whirlwind off the list at the time I needed to make the choice. Lack of testing does not mean a product is automatically better.

Amen, Bill.

I didn't care for the WW hub problems that they had early on and the CG was better for the -7 with the weight up front... that is why I chose Hartzell.

Les is a great guy and he knows his product very well.

Brian, i will be in a similar situation as you, as I have the G3i electronic ignition. Now, i don't have any way of analyzing engine pulses and how it subsequently resonates through the blade, but I will have the ability to shut off the ei from the pilot seat. Though, I think that I would prefer to leave it on and respect the Hartzell admonition about power setting, as it really isn't hard to respect.

I wish Hartzell would run our setup through testing, as it is a common RV setup nowadays.

CJ

[Brantel]

Originally Posted by DanH

Les has measured stress data from formal vibration surveys to guide his opinion, so I'd take the recommendation seriously. The prohibited power settings don't seem like something you would really miss anyway.

Dan, Trust me, I will trust Les's advice. Last thing I ever want is a blade departing my airplane!

I get confused however in the info that is out there. He said they have not tested the 1 mag/1 EI with advance...but have they?

On row 4 & 6 of this document: http://www.vansairforce.net/download..._Approvals.xls

It states that "Combination not tested - similar to Std. Mags." so this would leave me to believe that it would be OK to run with no restrictions.

Here is Les's personal response to my query:

"If you use the electronic ignition with fixed timing, then you should be Ok with no restrictions.

If you use the variable timing feature, you might want to follow the 200 Hp engine limitations just in case."


Other questions that come to mind are related to the fact that the PMag also uses manifold pressure to control the advance and under high manifold pressures, it reduces the amount of advance basically back to normal mag timing.

I know I can either live with the restrictions or I can use the software for the Pmag to limit the advance back to regular mag values.

Just want to fully understand all I can about this subject before I do something stupid.

[DanH]

Originally Posted by Sig600

Because of Hartzells operating restrictions that WW does not have, and the performance.

From the Whirlwind 200RV manual:

Originally Posted by Brantel

Here is Les's personal response to my query:

"If you use the electronic ignition with fixed timing, then you should be Ok with no restrictions.

If you use the variable timing feature, you might want to follow the 200 Hp engine limitations just in case."

Sounds sensible to me.

[RV7ator]

Brian,

I adhered to the mp/rpm limitation on ship #1 before Hartzell lifted it for 180hp. It's easy to live with. Full power, no problem. Cruise, no problem, lots of power setting choices.

Now I'm running 200+ hp parallel valve engines, BA prop, dual EI, 9.5:1, and wondering just what we're afraid of. I can't complain about Hartzell's willingness to supply some test info, but to frame a limitation as "constant" raises the question of what is "constant". Some period of time is o.k; how long is that before it becomes "constant"? Engine limitations I've encountered state measurable limits, e.g., <5 minutes @ full power.

So we're into crowd-sourcing data!! As for me, I tend to avoid Les' sensitive region simply because it is easily avoided without operational hindrance.

John Siebold