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Nosewheel vibration update

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jhnstniii(at)AOL.COM
Guest

Posted: Sun Aug 30, 2009 10:44 am Post subject: Nosewheel vibration update

Listers--Promised I would report on our efforts to stop the vertical vibration of our nosewheel/pant assembly. We started with the tire. We bought a motorcycle wheel balancer (simple rod rolling on ball bearing supports type) and immediately noticed the tire was quite out of round and out of balance. We thought "problem solved" and bought a new tire. This one was round. We added weights until it was balanced, and during taxi testing were surprised to find there was no improvement.  We then tried different combinations of tire pressure and bearing torque (within the required limits). The best was with very low tire pressure and medium torque, but we still had the problem at 20 mph or more.  So then we glassed a piece of wood (with four layers of medium weight glass) on to the leg from the bend at the bottom up to where it enters the cowling, hoping to change the vibration characteristics. No improvement!  I wonde  r if a little lead in the nose or tail of the pant might help (the pant is balanced fore and aft right now so doing this would actually unbalance it). We are running out of ideas. One of our hangar buddies was up at OSH watching the RVs taxi by for takeoff and he said many of them had vibrating nosewheels. We have the new type nosewheel fork. Don't know if there is a vibrational difference between this type and the old type. Any ideas? Thanks. LeRoy Johnston and David White RV-6A N176LD Esperanza 200+ hours flying.                  [quote][b]

Painless

Joined: 10 Jan 2006
Posts: 40
Location: Peshtigo, Wisconsin

Posted: Sun Aug 30, 2009 11:43 am Post subject: Nosewheel vibration update

This may seem rather rudimentary, but are you sure it is your nosewheel that is shimmying?  I thought I had a nosewheel shake as well until a local pilot saw me land while waiting at the hold short line and reported that my left main was the culprit.  I suspect uneven tire wear, but balancing out the wheel/tire resulted in some improvement.  I plan to replace the main tires/tubes at next conditional inspection.



Just a thought.  





Regards,

Jeff Orear

RV6A  N782P

Peshtigo, WI



On Aug 30, 2009, at 1:21 PM, jhnstniii(at)aol.com (jhnstniii(at)aol.com) wrote:

[quote]Listers--Promised I would report on our efforts to stop the vertical vibration of our nosewheel/pant assembly. We started with the tire. We bought a motorcycle wheel balancer (simple rod rolling on ball bearing supports type) and immediately noticed the tire was quite out of round and out of balance. We thought "problem solved" and bought a new tire. This one was round. We added weights until it was balanced, and during taxi testing were surprised to find there was no improvement.  We then tried different combinations of tire pressure and bearing torque (within the required limits). The best was with very low tire pressure and medium torque, but we still had the problem at 20 mph or more.  So then we glassed a piece of wood (with four layers of medium weight glass) on to the leg from the bend at the bottom up to where it enters the cowling, hoping to change the vibration characteristics. No improvement!  I wonde r if a little lead in the nose or tail of the pant might help (the pant is balanced fore and aft right now so doing this would actually unbalance it). We are running out of ideas. One of our hangar buddies was up at OSH watching the RVs taxi by for takeoff and he said many of them had vibrating nosewheels. We have the new type nosewheel fork. Don't know if there is a vibrational difference between this type and the old type. Any ideas? Thanks. LeRoy Johnston and David White RV-6A N176LD Esperanza 200+ hours flying.                  	  Quote: 	
		  

href="http://www.matronics.com/Navigator?RV-List">http://www.matronics.com/Navigator?RV-List

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[b]

_________________
Jeff Orear
RV6A N782P
Peshtigo, WI

dave.gribble(at)mchsi.com
Guest

Posted: Sun Aug 30, 2009 1:54 pm Post subject: Nosewheel vibration update

Some people have installed a $40 Matco axle that reduces rolling friction... and some people have changed to a $300 Grove nosewheel with conventional felt seals (instead of rubber seals) to reduce rolling friction.   What setup are you running? 

-------------- Original message ----------------------

From: jhnstniii(at)aol.com

 	  Quote: 	
		  

 Listers--Promised I would report on our efforts to stop the vertical vibration 

 of our nosewheel/pant assembly. We started with the tire. We bought a motorcycle 

 wheel balancer (simple rod rolling on ball bearing supports type) and 

 immediately noticed the tire was quite out of round and out of balance.?We 

 thought "problem solved" and bought a new tire.?This one was round.?We added 

 weights until it was balanced, and?during taxi testing were surprised to find 

 there was no improvement.? We then tried different combinations of tire pressure 

 and bearing torque (within the required limits).?The best was with very low tire 

 pressure and medium torque, but we still had the problem at?20 mph or more.? 

 So?then we glassed?a piece of wood (with four layers of medium weight glass) on 

 to the leg from the bend at the bottom up to where it enters the cowling, hoping 

 to change the vibration characteristics.?No improvement!? I wonder if a little 

 lead in the nose or tail of the pant might help (th

  e pant is balanced fore and aft right now so doing this would 

 actually?unbalance it). We are running out of ideas. One of our hangar buddies 

 was up at OSH watching the RVs taxi by for takeoff and he said many of them had 

 vibrating nosewheels. We have the new type nosewheel fork. Don't know if there 

 is a vibrational difference between this type and the old type. Any ideas? 

 Thanks. LeRoy Johnston and David White RV-6A N176LD Esperanza 200+ hours 

 flying.????????????????

carl.froehlich(at)verizon
Guest

Posted: Sun Aug 30, 2009 2:23 pm Post subject: Nosewheel vibration update

Two things to try:  

<![if !supportLists]>1.      <![endif]>Install the MATCO nose wheel axle.  Here is the link: http://www.matcomfg.com/AXLEASSEMBLYA24125INCH-idv-3657-1.html  This allows for the axle bolt to be fully tighten without too much pre-load on the bearings.  This help my 8A nose gear problem.  

<![if !supportLists]>2.      <![endif]>Do the same balance on the main gear that you did on the nose gear.  I noted a significant improvement on the nose gear shimmy after I replace my main gear.  

   

Carl Froehlich  

RV-8A (525 hrs)  

RV-10 (fuselage)  

   

       

From: owner-rv-list-server(at)matronics.com [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of Jeff Orear

 Sent: Sunday, August 30, 2009 3:31 PM

 To: rv-list(at)matronics.com

 Subject: Re: Nosewheel vibration update  

  

  

   

This may seem rather rudimentary, but are you sure it is your nosewheel that is shimmying?  I thought I had a nosewheel shake as well until a local pilot saw me land while waiting at the hold short line and reported that my left main was the culprit.  I suspect uneven tire wear, but balancing out the wheel/tire resulted in some improvement.  I plan to replace the main tires/tubes at next conditional inspection.    

   

    

Just a thought.    

    

   

    

   

    

Regards,  

    

   

    

Jeff Orear  

    

RV6A  N782P  

    

Peshtigo, WI  

    

   

    

       

On Aug 30, 2009, at 1:21 PM, jhnstniii(at)aol.com (jhnstniii(at)aol.com) wrote:  

  



 

   

Listers--Promised I would report on our efforts to stop the vertical vibration of our nosewheel/pant assembly. We started with the tire. We bought a motorcycle wheel balancer (simple rod rolling on ball bearing supports type) and immediately noticed the tire was quite out of round and out of balance. We thought "problem solved" and bought a new tire. This one was round. We added weights until it was balanced, and during taxi testing were surprised to find there was no improvement.  We then tried different combinations of tire pressure and bearing torque (within the required limits). The best was with very low tire pressure and medium torque, but we still had the problem at 20 mph or more.  So then we glassed a piece of wood (with four layers of medium weight glass) on to the leg from the bend at the bottom up to where it enters the cowling, hoping to change the vibration characteristics. No improvement!  I wonde r if a little lead in the nose or tail of the pant might help (the pant is balanced fore and aft right now so doing this would actually unbalance it). We are running out of ideas. One of our hangar buddies was up at OSH watching the RVs taxi by for takeoff and he said many of them had vibrating nosewheels. We have the new type nosewheel fork. Don't know if there is a vibrational difference between this type and the old type. Any ideas? Thanks. LeRoy Johnston and David White RV-6A N176LD Esperanza 200+ hours flying.                    	  Quote: 	
		   href="http://www.matronics.com/Navigator?RV-List">http://www.matronics.com/Navigator?RV-Listhref="http://forums.matronics.com">http://forums.matronics.comhref="http://www.matronics.com/contribution">http://www.matronics.com/contribution 	


  

   

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        [quote][b]

jhnstniii(at)AOL.COM
Guest

Posted: Sun Aug 30, 2009 3:24 pm Post subject: Nosewheel vibration update

We balanced the mains and they are round--no improvement. They don't vibrate.  It is very obviously the nose wheel because we've taxied by with one of us as observer at various speeds and with the stick in various positions.  The pant/wheel assembly is going up and down and you can feel it in the cockpit. We have the bearing with the rubber seals that has to be torqued to spec. Will check out the MATCO axle. Thanks.    

 

 

 --

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Sun Aug 30, 2009 3:45 pm Post subject: Nosewheel vibration update

Also balance the wheel pant. Lead shot can be glassed in to accomplish 

this, so the wheel pant is balanced about the axle.



jhnstniii(at)aol.com wrote:

[quote] We balanced the mains and they are round--no improvement. They don't 

 vibrate.  It is very obviously the nose wheel because we've taxied by 

 with one of us as observer at various speeds and with the stick in 

 various positions.  The pant/wheel assembly is going up and down and you 

 can feel it in the cockpit. We have the bearing with the rubber seals 

 that has to be torqued to spec. Will check out the MATCO axle. Thanks.    

 

 

 --

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

carl.froehlich(at)verizon
Guest

Posted: Sun Aug 30, 2009 4:09 pm Post subject: Nosewheel vibration update

Ok.  

   

When you get the MATCO axle, set it up so the wheel spins easily – just tight enough so there is no bearing slop.  

   

Carl  

     

From: owner-rv-list-server(at)matronics.com [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of jhnstniii(at)aol.com

 Sent: Sunday, August 30, 2009 7:24 PM

 To: rv-list(at)matronics.com

 Subject: Re: Nosewheel vibration update  

  

   

We balanced the mains and they are round--no improvement. They don't vibrate.  It is very obviously the nose wheel because we've taxied by with one of us as observer at various speeds and with the stick in various positions.  The pant/wheel assembly is going up and down and you can feel it in the cockpit. We have the bearing with the rubber seals that has to be torqued to spec. Will check out the MATCO axle. Thanks.    

 

 

 --

lifeofreiley2003(at)yahoo
Guest

Posted: Sun Aug 30, 2009 5:26 pm Post subject: Nosewheel vibration update

OMG... I've heard it all now  

--- On Sun, 8/30/09, Kelly McMullen <kellym(at)aviating.com> wrote:

[quote] From: Kelly McMullen <kellym(at)aviating.com>

 Subject: Re: Nosewheel vibration update

 To: rv-list(at)matronics.com

 Date: Sunday, August 30, 2009, 6:43 PM

 Kelly McMullen <kellym(at)aviating.com>

 Also balance the wheel pant. Lead shot can be glassed in to

 accomplish this, so the wheel pant is balanced about the

 axle.

 jhnstniii(at)aol.com

 wrote:

 > We balanced the mains and they are round--no

 improvement. They don't vibrate.  It is very obviously

 the nose wheel because we've taxied by with one of us as

 observer at various speeds and with the stick in various

 positions.  The pant/wheel assembly is going up and

 down and you can feel it in the cockpit. We have the bearing

 with the rubber seals that has to be torqued to spec. Will

 check out the MATCO axle. Thanks.    

 > 

 > --

Ed Anderson

Joined: 10 Jan 2006
Posts: 475

Posted: Mon Aug 31, 2009 3:43 am Post subject: Nosewheel vibration update

David, I have not gone back to the beginning of the thread, so don’t know what you have tried.  However, When I replaced the nose gear on my 98 RV-6A for the beefier version Van offered back almost a decade ago,  I notice a strange vibration – it did not feel like a side to side shimmy, but a back and forth type vibration.  An observer noted the nose wheel appear to be tucking rearward and then popping forward in small magnitude cycles.  That is what it felt like in the cockpit.  

   

I placed wood stiffeners around the nose rod and fiberglass them in – immediate this “tucking” sensation stopped.    

My $0.02  

Ed Anderson  

Rv-6A N494BW Rotary Powered  

Matthews, NC  

eanderson(at)carolina.rr.com  

http://www.andersonee.com  

http://www.dmack.net/mazda/index.html  

http://www.flyrotary.com/  

http://members.cox.net/rogersda/rotary/configs.htm#N494BW  

http://www.rotaryaviation.com/Rotorhead%20Truth.htm[url=http://www.dmack.net/mazda/index.html][/url]  

        

  

From: owner-rv-list-server(at)matronics.com [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of jhnstniii(at)aol.com

 Sent: Sunday, August 30, 2009 7:24 PM

 To: rv-list(at)matronics.com

 Subject: Re: Nosewheel vibration update  

  

   

We balanced the mains and they are round--no improvement. They don't vibrate.  It is very obviously the nose wheel because we've taxied by with one of us as observer at various speeds and with the stick in various positions.  The pant/wheel assembly is going up and down and you can feel it in the cockpit. We have the bearing with the rubber seals that has to be torqued to spec. Will check out the MATCO axle. Thanks.    

 

 

 --

_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com

bmeyette

Joined: 14 Mar 2007
Posts: 72
Location: Cornish, NH

Posted: Mon Aug 31, 2009 7:09 am Post subject: Nosewheel vibration update

I saw a video somewhere that showed major nosewheel vibrations  due the the harmonics of the leg flexing.   I believe he had put a  camera so it focused on the nose gear and the flex and vibration was  considerable.   It may have been on u-tube.  Seems your idea with  the wood would have helped with that, though.

   From: owner-rv-list-server(at)matronics.com  [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of  jhnstniii(at)aol.com

Sent: Sunday, August 30, 2009 2:21  PM

To: rv-list(at)matronics.com

Subject: Nosewheel  vibration update

Listers--Promised I would report on our efforts to stop the  vertical vibration of our nosewheel/pant assembly. We started with the tire. We  bought a motorcycle wheel balancer (simple rod rolling on ball bearing supports  type) and immediately noticed the tire was quite out of round and out of  balance. We thought "problem solved" and bought a new tire. This one  was round. We added weights until it was balanced, and during taxi  testing were surprised to find there was no improvement.  We then tried  different combinations of tire pressure and bearing torque (within the required  limits). The best was with very low tire pressure and medium torque, but we  still had the problem at 20 mph or more.  So then we  glassed a piece of wood (with four layers of medium weight glass) on to the  leg from the bend at the bottom up to where it enters the cowling, hoping to  change the vibration characteristics. No improvement!  I wonde r if a  little lead in the nose or tail of the pant might help (the pant is balanced  fore and aft right now so doing this would actually unbalance it). We are  running out of ideas. One of our hangar buddies was up at OSH watching the RVs  taxi by for takeoff and he said many of them had vibrating nosewheels. We have  the new type nosewheel fork. Don't know if there is a vibrational difference  between this type and the old type. Any ideas? Thanks. LeRoy Johnston and David  White RV-6A N176LD Esperanza 200+ hours  flying.                   	  Quote: 	

href="http://www.matronics.com/Navigator?RV-List">http://www.matronics.com/Navigator?RV-List

href="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c

No virus found in this incoming message.

Checked  270.13.71/2334 -  Release Date: 08/30/09 06:36:00

   [quote][b]

_________________
Brian Meyette, Cornish, NH

RV-7A QB tipup, supercharged Subaru STi engine, MT CS prop, all glass day/night/IFR panel, being built with solar and wind power

N432MM

http://brian76.mystarband.net/RV-7Ahome.htm

Jess
Guest

Posted: Mon Aug 31, 2009 8:13 am Post subject: Nosewheel vibration update

We had the same problem and converted to a 6 still the  problem, no one could give us the heat treat specs. sort of dodge around. Our  solution is quite easy, determine where you would install the wood stiffiners.  Order aluminum tubing from Spruce that has the ID of the tube that closely  matches your gear OD. Anneal the aluminum tube, slide it over the gear leg. Form  it into a streamline shape, determine where it will align with your gear  fairings. Mix MetlWeld also from Spruce and pour it into the aluminum (now  streamlined) tube. Turn it over a few times to make sure you have epoxy all the  way in contact with the main strut.  Align it to where you want it, install  a fiberglass arrow shaft in the void, pour the rest with MetlWeld tape off the  bottom so it will not run out. Let it cure, if on the mains it was recommend to  us by Van's to have the weight off of the gear. We have had no problem since and  it is quite light and strong. 

  

  In a message dated 8/31/2009 8:11:14 A.M. Pacific Daylight Time,  bmeyette(at)gmail.com writes:

  	  Quote: 	
		     I saw a video somewhere that showed major nosewheel    vibrations due the the harmonics of the leg flexing.   I believe he    had put a camera so it focused on the nose gear and the flex and    vibration was considerable.   It may have been on u-tube.     Seems your idea with the wood would have helped with that,    though.



         From: owner-rv-list-server(at)matronics.com    [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of    jhnstniii(at)aol.com

Sent: Sunday, August 30, 2009 2:21    PM

To: rv-list(at)matronics.com

Subject: Nosewheel    vibration update

   

Listers--Promised I would report on our efforts to stop the    vertical vibration of our nosewheel/pant assembly. We started with the tire.    We bought a motorcycle wheel balancer (simple rod rolling on ball bearing    supports type) and immediately noticed the tire was quite out of round and out    of balance. We thought "problem solved" and bought a new tire. This    one was round. We added weights until it was balanced, and during    taxi testing were surprised to find there was no improvement.  We then    tried different combinations of tire pressure and bearing torque (within the    required limits). The best was with very low tire pressure and medium    torque, but we still had the problem at 20 mph or more.     So then we glassed a piece of wood (with four layers of medium    weight glass) on to the leg from the bend at the bottom up to where it enters    the cowling, hoping to change the vibration characteristics. No    improvement!  I wonde r if a little lead in the nose or tail of the pant    might help (the pant is balanced fore and aft right now so doing this would    actually unbalance it). We are running out of ideas. One of our hangar    buddies was up at OSH watching the RVs taxi by for takeoff and he said many of    them had vibrating nosewheels. We have the new type nosewheel fork. Don't know    if there is a vibrational difference between this type and the old type. Any    ideas? Thanks. LeRoy Johnston and David White RV-6A N176LD Esperanza 200+    hours    flying.                   	  Quote: 	
		  



href="http://www.matronics.com/Navigator?RV-List">http://www.matronics.com/Navigator?RV-List

href="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c

	
 BR>Checked    270.13.71/2334 - Release Date: 08/30/09 06:36:00

 	  Quote: 	
		  



====================================

="http://www.matronics.com/Navigator?RV-List">http://www.matronics.com/Navigator?RV-List

====================================

ms.matronics.com/">http://forums.matronics.com

====================================

tp://www.matronics.com/contribution">http://www.matronics.com/contribution

====================================



	
	


 

  [quote][b]

jhnstniii(at)aol.com
Guest

Posted: Thu Sep 10, 2009 6:19 pm Post subject: Nosewheel vibration update

Carl--Thank you!  We installed the MATCO nosewheel axle yesterday, carefully re-balanced the wheel/tire, and the vibration is gone. Why it works I don't know but it does.  The list rules! 

   --LeRoy Johnston and David White RV-6A "Esperanza" (204 hours)

 

 

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