Walt

Walt

Well Known Member
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 :D

Needless to say John is very happy.

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

RV8%252520Dalham2.png.jpg



Spectrum Analysis: Good looking engine inside and running smooth.

RV8%252520Dalham1.jpg


Happy New year!
 
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!
 
Mirror vibration question...

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,
 
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 :D
 
Walt said:
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 :D
Click to expand...

Can't wait to see it. Simple is good because I understand it! ;)
 
SmilingJack said:
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,
Click to expand...

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.
 
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.
 
Smooooooooth

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.
 
Resonance.

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

jaba430


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

One of these days, I'm going to have to bring the RV-8 down to you to get its prop balanced. It's not bad, but I definitely know it could be made much smoother. Do you have a good way to tie the tail down to something solid to anchor it for the runup? Way back when we had just finished building the thing and were working on calibrating the fuel injection system and had it tied to a pickup truck's trailer hitch, under high power it felt like it was trying to pull the truck down the taxiway :eek: It also wanted to try to lift the tail up, requiring someone to stand back at the tail and help hold it down.
 
I was worried about the same thing. Walt had me put the flaps up, and the tailwheel was off the edge of the concrete pads plus we had chocks under the mains. For the first runup I brought it up slowly and held full up while feeling for the tail to start feeling light. It never did. Walt had me run it up to my normal cruise RPM (2300). Everything felt safe and worked fine.

I've got an 8 too so you should not have a problem.
 
I've done plenty of 8's and never had any issues. It helps to have a full load of fuel so fill it up before you come or when you get here and we can also throw some ballast in the back seat if it makes you feel more comfortable. Either way it will be fine, I alway remind folks to put flaps up and keep full aft stick to help keep the tail planted.
 
Walt said:
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.
Click to expand...

Walt, he used a Microvib. Not sure which Model.
 
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