C-FAH Q

C-FAH Q

Well Known Member
I am thinking of having my prop balanced and have a few questions.
1. What RPM do you do the Balance at ?
2. How is the airplane secured while doing the run up to the specified rpm? I can imagine. My plane wanting to sit still ontheground at 2400 rpm.
3. Is it best to tie the tailwheel down?
4. Any pictures of the sensor installation?

Thanks
 
C-FAH Q said:
I am thinking of having my prop balanced and have a few questions.
1. What RPM do you do the Balance at ?
2. How is the airplane secured while doing the run up to the specified rpm? I can imagine. My plane wanting to sit still ontheground at 2400 rpm.
3. Is it best to tie the tailwheel down?
4. Any pictures of the sensor installation?

Thanks
Click to expand...

1) I've done quite a few RV7's at 2400 RPM, this is normal cruise RPM for many folks.
2) A good load of fuel helps, flaps up, chocks and full aft stick on tail draggers.
3) You can tie off the tail wheel if it make you feel better, but not necessary.
4) Here is a LINK to a slideshow I have on my website showing sensor installation.
 
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Your claim in the signature block made me check my records.

I knew your airplane was fast but I had to check (it's an OCD thing). Good luck with the prop balancing. I had ours done at 2400.

Bob Axsom

Top end of records in SARL RV Blue Class.

209 AirVenture Cup 2008 7/27/08 RV Blue RV-8 Huft, John 217.17 249.91
1350 AirVenture Cup 2012 7/22/12 RV Blue RV-4 Travis, Brent 208.33 239.74
47 AirVenture Cup 2007 7/23/07 RV Blue RV-8 Huft, John 204.56 235.40
213 AirVenture Cup 2008 7/27/08 RV Blue RV-8 Ross, Jon 202.59 233.14
1353 AirVenture Cup 2012 7/22/12 RV Blue RV-8 Carroll, Alan 202.56 233.10
446 Grace Flight 2009 10/4/09 RV Blue RV-8 Huft, John 201.71 232.12
309 Taylor 100 2009 3/16/09 RV Blue RV-8 Huft, John 201.29 231.64
176 Colorado 150, 2008 6/29/08 RV Blue RV-8 Huft, John 199.27 229.31
429 Pagosa Springs 100 2009 9/27/09 RV Blue RV-8 Huft, John 199.38 229.29
296 Rocket 100 2008 11/23/08 RV Blue RV-8 Huft, John 197.43 227.20
1357 AirVenture Cup 2012 7/22/12 RV Blue RV-6 Barnes, Jeff 196.51 226.14
1286 GNAR III, Ephrata, WA 6/16/12 RV Blue RV-4 Travis, Brent 195.69 225.20
779 Rocket 100, 2010 11/20/10 RV Blue RV-8 Rovey, Jason 195.44 224.90
1358 AirVenture Cup 2012 7/22/12 RV Blue RV-6A Axsom, Bob 195.26 224.70
1311 BSAR II, Three Forks, MT 7/7/12 RV Blue RV-4 Travis, Brent 194.96 224.36
116 Rocket 100, 2007 11/18/07 RV Blue RV-8 Huft, John 194.78 224.15
217 AirVenture Cup 2008 7/27/08 RV Blue RV-6A Axsom, Bob & Jeanine 194.56 223.89
218 AirVenture Cup 2008 7/27/08 RV Blue RV-8 Carroll, Alan 193.76 222.97
781 Rocket 100, 2010 11/20/10 RV Blue RV-7 Wilcox, Gary 193.72 222.92
 
Balance complete

I did my prop balance today with a dyna vibe. First I had to make some brackets to hold the sensors. Here are the numbers for start and finish, won't bother with the four other runs in between.

Run # 1
2200 rpm. .28 ips. 114*
2300 rpm. .23 ips. 101*
2400 rpm. .18 ips. 55*

Final run # 6
2200 rpm. .05 ips. 59*
2300 rpm. .06 ips. 25*
2400 rpm. .05 ips. 008*

What seemed to work best was a An4-9 bolt, three washers and a metal lock nut
On the fly wheel at the 180* position. I had to put the bolt in from the rear of the flywheel or the bolt would contact the belt as it went past.

I am very happy with the results on the ground. Without a doubt, it was smoother during the ground runs between start and finish. I spent 4.5 hours from start to finish including making brackets and reading the manual about 4 times. 3 hours would be easily achievable after doing a couple more balances.
 
I need my prop re-balanced. I know a person can't tell the difference from 100 to 55....but mine seems rougher than a year ago. And after my exhaust failure, i wonder if something has shifted as it was shaking badly.

Also i really wished I would have run in the AVC this year, so I could claim Fastest RV-7 Blue class. ;)
 
Opportunity Lost

HAHAHAHAHAHAHAHAHA I liked that last part. It was the opportunity of a life time You, Bob Mills and I'm sure several others felt the same way but at least you two guys chose the higher ground and were where you should have been. Well OK, I'm not so sure about you Brian, couldn't you have told your wife that Mitchell was Oshkosh - she hadn't been there before, just another airport, right...

Seriously, i tried to talk a guy visiting from Yankton in his RV-9 with a Subaru engine into flying in the RV Red Class. It had ZERO entries. He would have gotten a 1st Place Trophy, set a new class record and he would have been famous forever with his name passed from RV builder/pilot to RV builder/pilot with great reverence. I could see in his eyes that he was seriously going through the "what will I lose if I do this thought process" as his tall good looking female companion (wife?) walked up but alas he chose the path traveled by many.

I wish you, Bob Mills, Garry Wilcox, Tom Martin, Wayne Hadath, Bill Beaton, Jason Rovey, Jerry Hajek, Gary Shelley, Ken Krebaum, Mark Fredick, Mike Thompson, James Redmon, Bobby Bennett, Ann Elise Bennett, Alan Crawford, Dennis Collins, Red Hamilton, Marilyn Boese, Terry Hines, Harry Hinckley, Tom Moore, Chris Murphy, James Porter, Rhea Sherwood, Duncan Southerland, Ernie Sutter, Bob Vasey and the rest of the usual suspects could have been there. It was the absolute best opportunity to fly fast that I have ever seen - God it was great! Eric Whyte and his teamed pulled triumph out of chaos. Sorry you all missed it.

Bob Axsom
 
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Walt - this is probably a dumb question but here goes.

How do you test run at 2400rpm ?

With my old prop (Aymar Demuth) my static was 2300 rpm (2200 in the winter).
With my new prop (testing a Catto) my static is 2050 rpm.

Unless I fly out to Colorado or something, I don't think I'll ever see 2400 rpm on the ground.
 
See, I feel SOOOO dumb. I should have seen that one coming.

I assume a fixed pitch prop is balanced at max static rpm ?
 
The above is correct, only the CS prop can be done that high. We do fixed pitch at max static RPM which is generally in the 2100-2200 range.

From experience I can tell you that there is very little vibration difference between 2100 and 2400.
 
As always, thanks for the info Walt. Wish I were closer to TX but I have found a Virginia shop that comes recomended for prop balancing. As soon as I install the Catto "for the last time" I'll get it alanced :)
 
humptybump said:
As always, thanks for the info Walt. Wish I were closer to TX but I have found a Virginia shop that comes recomended for prop balancing. As soon as I install the Catto "for the last time" I'll get it alanced :)
Click to expand...

And where is that shop Glen? I am interested. Maybe we can get a group discount? :)
 
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