Whirlwind vs Hartzell- Vibration survey, testing and operational limitations

jj_jetmech · #1 12-21-2014, 05:07 PM

I have ended up with a IO360 A1A. I had planned a p-valve 360 but an option came my way and I'm moving this direction now. Plus there's things I like about the angle valve engine... Knowing this engine is 20-25lbs heavier per the TCDS I'm gravitating towards the WW 74 or 200... As it is 10lbs lighter than the BA..

Clearly there are greater considerations than just the actual weight of the propeller..

These other considerations have taken me exactly where many of you have already gone... I had knee surgery on Thursday so I'm stuck on the sofa and have spent no fewer than 10 hours reading about Tosional Vibration, Power Pulses, Inertia etc... Including but not limited to previous VAF threads and P&W's document about development of the R-2800.. Not trying to start that debate but based on what I have learned I have questions.

WW states the following in their manual:

Recommended Non-Continuous Operating Ranges

Whirl Wind follows historical industry standards and recommends that continuous operation between 2,050 - 2,300 RPM and 2,600 - 2,700 RPM be avoided when used on Lycoming and similar four cylinder aircraft engines. (Take off and climb out is not considered continuous operation.)

This seems to be a blanket statement. Is this based on real data or vibration surveys by WW? Why is there no mention of M.P. Limitations? Hartzell has provided data and limitations specific to each model Lycoming as they operate in the certified world and apparently have done real testing..

I'm going to call Lycoming, Hartzel and WW tomorrow. In the mean time can anyone provide further detail or links to previous discussions that address this question...

I get the feeling the testing has been done by the customers. I've heard great things about WW props but need just a little more info before also becoming a customer..

Thanks,

ColoRv · #2 12-21-2014, 05:42 PM

I have an angle valve, non-counterweighted, 10:1, Pmags and a whirlwind. I follow their recommendations but those ranges are not something I would typically cruise in anyway. I think you will find similar restrictions on metal props, with additional queasiness about high compression and electronic ignition if you have any interest I such things.

As for CG, I can't get into the forward 10% no matter how I load whereas going off the aft end is pretty easy. Some more weight up forward wouldn't hurt my feelings.

jj_jetmech · #3 12-21-2014, 05:49 PM

Quote:

Originally Posted by ColoRv

I have an angle valve, non-counterweighted, 10:1, Pmags and a whirlwind. I follow their recommendations but those ranges are not something I would typically cruise in anyway. I think you will find similar restrictions on metal props, with additional queasiness about high compression and electronic ignition if you have any interest I such things.

As for CG, I can't get into the forward 10% no matter how I load whereas going off the aft end is pretty easy. Some more weight up forward wouldn't hurt my feelings.

Your just the guy I was looking for! Which WW... What is your BEW?

Thanks

jj_jetmech · #4 12-21-2014, 05:59 PM

I think you will find similar restrictions on metal props, with additional queasiness about high compression and electronic ignition if you have any interest I such things.

Yes, interested in both area's... The Side effects of both especially with a metal prop have driven me to this research or gathering of data...

How many hous on your combination?

BillL · #5 12-21-2014, 06:23 PM

I think you will find that there is no operating limitation on the Hartzell composite prop. An answer from Hartzell is needed for action.

jj_jetmech · #6 12-21-2014, 06:29 PM

Quote:

Originally Posted by BillL

I think you will find that there is no operating limitation on the Hartzell composite prop. An answer from Hartzell is needed for action.

That's correct. $12,250

schristo@mac.com · #7 12-21-2014, 06:35 PM

I have and angle valve 390 with a WW200 and wondered the same thing several years ago and called the company... talked with a tech / engineer who said that they did not test specific combinations but defaulted to other published testing.

I was mostly interested in pursuing higher speeds for SARL racing at the time. My memory of the call was that they were not patricianly concerned about the lower range.

I have tested quite a bit for the best RPM and speed combination for top speed and found that 2650 was about it for me and have run races around that target.

With more than 1,050 hours so far I continue to fiddle with the knobs whenever I am cruising along and have tried just about every combination.

I default to 2350-2400 RPM for most flights as the best overall smoothness / performance / sound.

hydroguy2 · #8 12-21-2014, 06:40 PM

EDIT: i see stephen already reported

Talk to Stephen Christopher. He has a WW200 on his IO-390 angle valve motored RV-7. I think over 1000hrs with lots of Acro, formation and racing.

I like my WW200, but only have 270hrs and a parallel valve 360 with 9:1 comp. & dual Pmags. I cruise at 2300-2500 depending on where I'm going. and limit RPM to 2600 during races. No issues so far.

jj_jetmech · #9 12-21-2014, 07:19 PM

[quote=schristo@mac.com;943600]I have and angle valve 390 with a WW200 and wondered the same thing several years ago and called the company... talked with a tech / engineer who said that they did not test specific combinations but defaulted to other published testing.

Your 390 is with counterweights right?

A IO360 A1A is without, this changes everything I think?

rvbuilder2002 · #10 12-21-2014, 11:41 PM

I have worked with Hartzell engineering doing dynamic propeller testing.

It requires a lot of special equipment, and sometimes a lot of time investment to complete a test program.

I do not know a lot about the specifics, but one take away I have is that small changes to a propeller can induce large changes in the dynamic interaction between a propeller and an engine.

In simpler terms, setting RPM limitations on a particular propeller, based on the test results of a totally different propeller is a total WAG.

It is entirely possible that the different propeller wouldn't need any RPM limitations on it at all, or that they should actually be more restrictive. Without doing the testing it is pure guessing.

The proof of that for me has been being involved in prototype propeller tests (designed using all of the knowledge and experience Hartzell has) and seeing them totally surprised by the results. But hey, that is why they do the testing.