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  #61  
Old 04-13-2023, 03:11 PM
Tacco Tacco is offline
 
Join Date: Jan 2017
Location: White Salmon, WA
Posts: 261
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I think everyone is overthinking this. It's simple. Buy one of these, ~$50. Spin it by hand and let it settle. Use those sticky auto weights on the inside race of the rim. NEVER place anything inside the tire where it could puncture the tube. I check the nose wheel every annual whether or not I've felt vibration. It's super easy.

There is really no need to balance the mains unless they're really gross. Bearing drag will stop them from rotating shortly after takeoff.

See this video if you don't believe me.

https://youtu.be/P5N8C4_f8eE
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RV-12 N12SM
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  #62  
Old 04-13-2023, 03:22 PM
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Draker Draker is offline
 
Join Date: Jun 2016
Location: Cameron Park, CA
Posts: 913
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Nice thread. I am chasing an intermittent vibration issue on my -7A, and I would not have thought to suspect gear legs or wheels.
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RV-7A (N12VD): Flying RV in Phase 1
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  #63  
Old 04-20-2023, 06:29 AM
Reilly Reilly is offline
 
Join Date: Oct 2008
Location: South Africa
Posts: 70
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Thought I would share my vibration issue. I have a original 12 with AM15 engine.
Also have experienced a shudder after lift off for a few seconds on every takeoff.
After reading this thread I checked my nose wheel and found it to be out of round and unbalanced. Fitted with a Vans supplied Aero Classic.

Not sure if it's a manufacture fault or from standing prolonged on the same spot during build.

I did not want to try balancing it like that so bought a new Goodyear.
Lined the valve up with the red dot and it was in perfect balance.

Test flight today with no vibration and shudder at all

Also found that the RHS fairing bracket had cracked due to this as well.
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  #64  
Old 05-19-2023, 12:34 PM
Hotscam Hotscam is offline
 
Join Date: Mar 2011
Location: Bosschenhoofd, Netherlands
Posts: 174
Default noting works

Bougth a new tyre (Michelin) which is even better quality than Aero Classic.
Balanced it dynamically up to about 3000 rpm. Perfect
Nothing changed. Bad vibration in take off and every time you climb.

The only thing that works is taking the pant off. All gone.

My guess
it seems like the wheel spins very fast with the pant and just the lower half sticking out to excite it.
Without the pant both upper and lower side get the same airflow which stops or reduces the spin.
To prove this I fitted a rubber flap rubbing against the tyre to add drag, which proved this point. The flap is gone after one flight so no permanent solution.
Not so easy to brake this wheel in a safe way

regards

Jack
Netherlanda
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PH-SEP and PH-SES

RV12 #120519 and #120790
Hobbs 700+ hours and 400+ hours
Dual SV1000 Skyview 15, Pocket FMS and Powerflarm 6.0 (ADSB)

RV10 PH-USN Hobbs 350 hours
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  #65  
Old 05-19-2023, 01:11 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 10,199
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Quote:
Originally Posted by Hotscam View Post
Bougth a new tyre (Michelin) which is even better quality than Aero Classic.
Balanced it dynamically up to about 3000 rpm. Perfect
Nothing changed. Bad vibration in take off and every time you climb.

The only thing that works is taking the pant off. All gone.

My guess
it seems like the wheel spins very fast with the pant and just the lower half sticking out to excite it.
Without the pant both upper and lower side get the same airflow which stops or reduces the spin.
To prove this I fitted a rubber flap rubbing against the tyre to add drag, which proved this point. The flap is gone after one flight so no permanent solution.
Not so easy to brake this wheel in a safe way

regards

Jack
Netherlanda
Jack
I think the fact that others have totally resolved a vibration problem by balancing the nose wheel assembly of their RV-12, and since you have proven that your nose wheel rotating is causing your vibration, it proves that even though you say yours has been balanced, that it actually is not (unless your airplane has some amazing mods that allows to fly at Mach .9 or some other crazy fast speed )
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Scott McDaniels
Hubbard, Oregon
Formerly of Van's Aircraft Engineering Prototype Shop
FAA/DAR, A&P, EAA Technical Councelor
RV-6A (aka "Junkyard Special ")
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  #66  
Old 05-31-2023, 06:36 AM
FitzRX7 FitzRX7 is offline
 
Join Date: Jan 2013
Location: FL
Posts: 117
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Posting this to multiple balance threads so people don't go on the wild goose chase I just did:

Harbor Freight/Amazon cones (1 1/8") no longer fit the either with bearings (not best option) or even close to bearing races. According to another VAF'r if you purchase the "DC42 Parts" from here (http://www.marcparnes.com/Ducati_Mot...ancer.htm#DU42) for $50 shipped you'll be able to use the $50 balancer. $100.

Another option which I wish I had seen before assembling the HF one is from Desser, $100 for a bubble balancer style desktop unit that doesn't have bearings that will rust out. (https://shop.desser.com/desser-ga-05...detail/324692/). Another bonus is you don't have to pull out bearings to get a decent balance like you do with the HF type.

YMMV, hopefully not as many miles as I had.
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  #67  
Old 05-31-2023, 11:01 AM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 10,199
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Quote:
Originally Posted by FitzRX7 View Post
Another bonus is you don't have to pull out bearings to get a decent balance like you do with the HF type.
I have always balanced with the bearings still in place. They have enough friction from the rubber seal that they don't rotate. The cones included with the HF balancer fit in the bearings fine.

What is the reason for balancing with the bearings removed?
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Opinions, information, and comments, are my own unless stated otherwise.
You are personally responsible for determining the suitability of any tips, ideas, etc. obtained from any post I have made in this forum.


Scott McDaniels
Hubbard, Oregon
Formerly of Van's Aircraft Engineering Prototype Shop
FAA/DAR, A&P, EAA Technical Councelor
RV-6A (aka "Junkyard Special ")
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  #68  
Old 06-01-2023, 12:00 AM
Hotscam Hotscam is offline
 
Join Date: Mar 2011
Location: Bosschenhoofd, Netherlands
Posts: 174
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Quote:
Originally Posted by rvbuilder2002 View Post
Jack
I think the fact that others have totally resolved a vibration problem by balancing the nose wheel assembly of their RV-12, and since you have proven that your nose wheel rotating is causing your vibration, it proves that even though you say yours has been balanced, that it actually is not (unless your airplane has some amazing mods that allows to fly at Mach .9 or some other crazy fast speed )
Scot

That might be the case and will try again, but does mot explain to me why the old nose leg and fork did not have this problem at all
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Jack Netherlands

PH-SEP and PH-SES

RV12 #120519 and #120790
Hobbs 700+ hours and 400+ hours
Dual SV1000 Skyview 15, Pocket FMS and Powerflarm 6.0 (ADSB)

RV10 PH-USN Hobbs 350 hours
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  #69  
Old 06-01-2023, 05:35 AM
BillL's Avatar
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 7,109
Default Maybe expand the possible list?

Quote:
Originally Posted by Hotscam View Post
Scot

That might be the case and will try again, but does mot explain to me why the old nose leg and fork did not have this problem at all
Jack, I don't know much about the 12, but I was flying with a friend and noticed his front gear was vibrating and the wheel turning in flight. He was happy to know as he was sorting an inflight vibration. Also, after sitting, my tires will have a flat spot and that affects the balance.
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RV-7
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  #70  
Old 06-02-2023, 05:58 AM
Piper J3's Avatar
Piper J3 Piper J3 is offline
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,930
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I installed a new nose wheel tire and Michelin AirStop ($150) during Annual Condition Inspection back in March. I did the wheel balance with the wheel installed on the nose fork and Iím not happy with outcome. I now balanced on a Harbour Frt balancer and had to add 2 oz more to get good balance.

Tire is 5.00x5 Aero Classic LSA. The tire did not have a painted dot to indicate light portion of tire. Normally the dot is placed to offset the weight of the valve stem and things work out pretty well. I now have 14 pcs of ľ ounce lead weights placed inside the wheel hub and packed around the valve stem. This is wild... I used some Gorilla Glue to prevent weights from shaking loose when wheel spins up suddenly. I plan a test flight tomorrow.
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Jim Stricker - EAA #499867
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Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 850

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