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Balance on my Prop! WOW!

PerfTech

PerfTech

Well Known Member
... I finely decided to get my Whirlwind C/S prop balanced. As it turns out I should have done this a long time ago. The difference is fanominal. It literally feels like another airplane. Smoother, quieter and it seem to even perform better, as if it is running more freely. My prop is a variation on the RV-200 style and is a vary high quality product that we installed one year ago. I now have 265 hrs. on it and always thought it was fine. Now I am perturbed with myself for not doing this sooner. I would highly recommend the dynamic balance and feel it is money well spent. Thanks, Allan ... :D
 
Yea, it is one of those things that until you do it, you have know way of knowing whether you need to.
Some are already pretty good and it doesn't help a noticeable amount, but most have at least some level of improvement where you can at least tell a slight improvement, and sometimes it is significant.
 
When I had my prop balanced

I really could not feel much of a difference, but after it was balanced, when we ran another test, my static max RPM increased by 53 RPMs so as you said it does seem to improve performance. RV-8a. 0-360 FP Sensenich
 
Obviously if your system is out of static balance ...

Glad it worked for you. I found no improvement at all.

Bob Axsom
 
Geico266 said:
The human body can only detect a certain level of vibration. Rest assured your avionics and air frame knows the difference.
Click to expand...

It's not just the level but the frequency of the vibration. Humans are mainly sensitive to low frequencies when it comes to 'feel' which to a large extent is the 1/2 (half prop speed) and 1st order (prop) vibrations (20-40 HZ).

However reducing the first order prop vibration will result in a lower higer order vibrations. These higher order vibrations are also what cause cracking and other related fatigue failures.

I have also observed that most folks won't 'feel' much improvement going from moderate (0.2 IPS) to very low levels (0.05 IPS) but they can always feel it when going from high (0.5 IPS or higher) to moderate levels. So even though you may not always 'feel' a significant improvement, that doesn't mean it didn't do anything, just that you personally couldn't feel it.

Here's an example of a spectrum analysis showing the the full range of frequencies, you can only 'feel' the prop crankshaft speed and below:

RV8%2520Dalham1.jpg
 
Hi Guys,

When I did my dynamic propeller balance with the help if a friend, we started with 0.42 ips and ended up with 0.07 ips.

There is a noticeable reduction in airframe vibration /stick vibration.

Does anyone know how much difference it would make to the overall balancing exercise by not being able to achieve cruse RPM?

My RV7 has an YIO-360-M1B with fixed pitch Sensenich prop, static rpm is 2300rpm.

Cheers
 
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eddieseve said:
Hi Guys,

Does anyone know how much difference it would make to the overall balancing exercise by not being able to achieve cruse RPM?

My RV7 has an YIO-360-M1B with fixed pitch Sensenich prop, static rpm is 2300rpm.

Cheers
Click to expand...

I have found there is generally a very minimal difference in vib level between 2200-2500 rpm.
 
Vans currently ships the YIO-540 with dual groove flywheel (for Brazilian AC support). But the flywheel is solid and does not include any machine or relief holes that I understand are often used to hold balancing weights determined in a prop balance. Can you still balance the prop if the flywheel is solid?
 
Huge deal

Yes it is a huge deal to get the prop balanced. I also have a WW RV200 and had it balanced in Mesa AZ. He got it to a 0.00!!! The 200 is already smooth but when balanced, it is amazing.

Plus, WW recommends getting it balanced within the first 10 hours of operation. I know that it can be impractical but should be done ASAP. Don't know if warranty would be affected but why chance it.
 
What's wrong with DynaVibe?

Hey Walt, would you care to elaborate? I am sure the system you are using is better, I am not questioning that one bit. I am asking for some education on why the system you use is better than the DynaVibe. Or limitations / issues you see with the DynaVibe system.

Full disclosure: I do not own, but have used the DynaVibe to balance my Hartzell prop. Was easy to use and noticed a considerable difference. I believe my IPS final reading was 0.05

Thanks,

Dan
 
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Omega232Devils said:
Hey Walt, would you care to elaborate? I am sure the system you are using is better, I am not questioning that one bit. I am asking for some education on why the system you use is better than the DynaVibe. Or limitations / issues you see with the DynaVibe system.

Full disclosure: I have used the DynaVibe to balance my Hartzell prop. Was easy to use and noticed a considerable difference. I believe my IPS final reading was 0.05

Thanks,

Dan
Click to expand...

Merely an observation, the only '0.00' vibration numbers I've ever seen/heard of were obtained using the DV. I know the resolution is less (.00 vs .000) but I also suspect the sensor sensitivity and filtering is what results in the lower resolution. I'm sure the unit does a good job perhaps with a bit less accuracy is all.

The vibration sensor I use costs half as much as their entire unit.
 
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Nope!!

Walt said:
Let me guess, he was using a DynaVib....
Click to expand...

No Walt, he uses Aces equipment. Here's a piece of recent email to our AZ RV list when someone inquired about balancing. His name is Andy Elliot. Very professional and reasonably priced.

"I do dynamic propeller balancing at Falcon using ACES professional
equipment. I guarantee a final level of max 0.07 IPS RMS, but usually do
much better than that on RVs. Getting a dynamic balance prior to leaving on
that long trip to Oshkosh will save wear and tear on both the plane and the
crew." Andy Elliot
 
Balancing cost in the USA

Walt and others

Would you guys mind telling me the average cost you normally pay to get your prop balance in the USA. For a 3 bladded prop for example??

That will give me a benchmark to compare with what is available north of the border..

Anyone doing balancing during Oshkosh?? I wouldn't mind getting mine balance if I could..

Thanks

Bruno
[email protected]
 
I still charge $175 for experimentals and $225 for most certified aircraft.

I would love to do some balancing at Osh but the politics/logistics of that is more than I am willing to deal with plus the added weight of equipment would be a problem.
 
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Should have minimal effect as long as EVERTHING goes back on exactly as it came off.
 
Propeller Balancer

Now I have to make a propeller balancer because my propeller has some vibration to it also. There is a fellow RV flyer up by Minneapolis that made a wheel balancer so I copied his great idea to make a flywheel balancer. By the way it works great and the balancer was easy to build..
 
balancing ww200rv

I haven't had my ww200rv prop balanced yet, but wondering where and how do you attach the balance weights?
 
On a lycoming I use the flywheel holes, this is an approved location for adding balance weights.
 
Thanks Walt. I was surprised to see my friend's Mooney has balance weights on the spinner backing plate. Seems like that would be a rather weak spot to add an asymmetric force.
 
The spinner bulkhead is an approved location to mount weights and this is where I put them on most certified aircraft because the flywheel holes are not available (used to mount the spinner). Continentals have no flywheel so they are always are mounted on the spinner bulkhead.
 
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