RV-8 Prop Balance Results

Walt · #1 12-31-2011, 05:08 PM

Just thought you'all may be interested in today's prop balance. John brought this over for a vib check today as he has noticed a "slight" vibration, turns out it was more than 2X the upper limit! We improved it from 0.414 IPS down to an amazing low 0.016 IPS

Needless to say John is very happy.

Plot of balance Run: 1) 0.414, Run 2) 0.170, Run 3) 0.016

Spectrum Analysis: Good looking engine inside and running smooth.

Happy New year!

Geico266 · #2 12-31-2011, 05:25 PM

Nice work Walt.

It was a pleasure meeting you n the RV -1 project. Thanks for taking the lead with the avionics and wiring. You da man!

SmilingJack · #3 12-31-2011, 05:32 PM

Walt, again, nice work and I have a question for you.

My guy was able to get my vibes down to .008, yes I feel lucky and do feel the difference by completing aprons balance,

So, here is my question: on my RV-8 I have 2 mirrors mounted on the roll bar. Why is the right hand mirror rock solid clear with zero vibration noticed while the left hand mirror is not clear and vibrates?

Is it because of the prop rotation?

Any suggestions on reducing the vibrations in it?

Thanks,

Walt · #4 12-31-2011, 05:38 PM

Same here Larry, great meeting you.

I really enjoy doing avionics work, it's always been good therapy for me. My RV1 design philosphy is "how simple can I make this thing" so from that perspective it's a bit of a challenge.

I think I have it down to 1 relay, 2 switches and about a dozen wires, pretty good for a airplane with a starter, alternator, transponder and com radio. I'm really keeping this one "light and simple", just like our founding father would have liked it

Geico266 · #5 12-31-2011, 05:40 PM

Quote:

Originally Posted by Walt

Same here Larry, great meeting you.

I really enjoy doing avionics work, it's always been good therapy for me. My RV1 design philosphy is "how simple can I make this thing" so from that perspective it's a bit of a challenge.

I think I have it down to 1 relay, 2 switches and about a dozen wires, pretty good for a airplane with a starter, alternator, transponder and com radio. I'm really keeping this one "light and simple", just like our founding father would have liked it

Can't wait to see it. Simple is good because I understand it!

Walt · #6 12-31-2011, 05:46 PM

Quote:

Originally Posted by SmilingJack

Walt, again, nice work and I have a question for you.

My guy was able to get my vibes down to .008, yes I feel lucky and do feel the difference by completing aprons balance,

So, here is my question: on my RV-8 I have 2 mirrors mounted on the roll bar. Why is the right hand mirror rock solid clear with zero vibration noticed while the left hand mirror is not clear and vibrates?

Is it because of the prop rotation?

Any suggestions on reducing the vibrations in it?

Thanks,

As far as the Mirror I really have no idea why one would be so much different than the other unless the mount is not exactly the same. The 8 rollbar is so small and the distance between the 2 mirrors is quite minimal so it does seem strange they would be different.

PS: I'd be curious to know what machine he is using just for reference.

odens_14 · #7 12-31-2011, 05:55 PM

does anyone know someone who does this in the "RV range" of vermillion, SD. I think I have a fair amount of vibration in my rv and would love to smooth it out.

Bubblehead · #8 12-31-2011, 07:55 PM

Just a note to say thanks to Walt for excellent work and a pleasant visit too. Walt did the leak test on my static system and a W&B a month or so ago, and so I wanted to use him for the balancing act too. My 8 always vibrated a little especially when throttling up to about 2000 rpm to cycle the prop. That vibration went away after Walt added the first trial weight.

The smoothness was very noticable even on runup and the engine felt wonderful climbing out from 52f to go back to Hicks. 5 minutes into the flight home I was smiling and enjoying the new sense of confidence that having a smoother running engine brings. Of all I've spent on this plane, this was the best bang for the buck.

pierre smith · #9 01-01-2012, 05:45 AM

We balanced my 110" prop on the Air Tractor to almost no numbers and it is really, really smooth.

Nevertheless, the engine has very high pitched resonance and even the trim tab pushrod bushings wear yearly.....amazing. The compressor section typically operates at 92-95% of 37,500 RPM..no typo! Double checked.

On the -10, we balanced it carefully and you'll be amazed at how little maintenance a balancing job provides. Exhaust pipes and welds not cracking, alternator mounts not loosening or cracking, etc....the benefits to balancing are too many too name.

Best,

RV10inOz · #10 01-01-2012, 03:48 PM

Balancer might not be as fancy as Walts, but we got this result on the -10 and she felt like a turbine.

http://s849.photobucket.com/albums/a...filter=noflash

This tells you one thing...... You need more decimal places!