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Maintenance Tips

Main Gear vibration during flight
Author Last Post
The Snider speed kit did not alleviate the vibration on my 180H.  I think the promotional material claimed to do so and thereby achieve the increase of plus five knots of cruise speed.  

   Douglas Isern
  
   303 279 4567
   P.O. Box 276
   Golden, Colorado 80402

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On Fri, Dec 22, 2017 at 3:16 PM, hilltop180 (hilltop180@hotmail.com) <mailer@mail2.clubexpress.com> wrote:
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Gear shake is common to the 170, 180, and 185. I have seen it on all three types. My 170 has 6.00-6 tires, wheel pants, and cruises at 105mph indicated, the gear shakes. My 180 has 8.50-10 tires with 10" wheel adapters, cruises at 150mph with a P-Ponk 520, the gear shakes, my 185 on 8.50-10 with 10" wheel adapters did the same.

All three planes have the shims properly tapped into place and the gear is not loose. The gear has a positive angle of incidence of its own and the buffet is probably the gear stalling all the time and/or it could be a vortex-shedding issue that might go away with Snider full length gear fairings but I have no experience with those.

 
Gear shake is common to the 170, 180, and 185. I have seen it on all three types. My 170 has 6.00-6 tires, wheel pants, and cruises at 105mph indicated, the gear shakes. My 180 has 8.50-10 tires with 10" wheel adapters, cruises at 150mph with a P-Ponk 520, the gear shakes, my 185 on 8.50-10 with 10" wheel adapters did the same.

All three planes have the shims properly tapped into place and the gear is not loose. The gear has a positive angle of incidence of its own and the buffet is probably the gear stalling all the time and/or it could be a vortex-shedding issue that might go away with Snider full length gear fairings but I have no experience with those.
 
I have noticed that on my 58 180 years ago and switched from 8.50 to 8.00 tires and it was reduces considerable.
I now have a 185 with 8.00 and yes the wheel oscillates slightly at about 1Hz. I think its just a function of the larger tires. 
 
 Start with....Check/balance prop to engine.....change tire size....check engine mounts....look for cowl wear or other odd broken clamps that would suggest a vibration somking rivits etc....add hub cap and inner wheel fairing.....make sure gear bolts are tight....

      The vibration could be coming from somewhere else to....

On Tue, Dec 19, 2017 at 8:33 AM, Grant Wittenborn (Grant.Wittenborn@gmail.com) <mailer@mail2.clubexpress.com> wrote:
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I thought I'd resurrect this thread from 2006 in case any new information has come up. 

I've got 8.50 x 10 tires/wheels installed on a newly acquired 185.  I noticed that in smooth air in cruise I have an airframe vibration at about 1 HZ with an amplitude large enough I can feel it in my seat and see it moving the instrument panel.  I look out the window and the gear is moving at the same frequency.

I'm suspecting an aerodynamic influence (vortex shedding) on the tires that is generating this movement.  Couple that with the large mass of the tire/wheel combination, the long arm of the gear leg, and it's easy to see how a shake can develop.

One suggestion I've seen is to put a hub cap on the wheel to smooth the airflow around the cylindrical wheel. Any other ideas besides checking the wedges on the gear attach points?


 
I thought I'd resurrect this thread from 2006 in case any new information has come up. 

I've got 8.50 x 10 tires/wheels installed on a newly acquired 185.  I noticed that in smooth air in cruise I have an airframe vibration at about 1 HZ with an amplitude large enough I can feel it in my seat and see it moving the instrument panel.  I look out the window and the gear is moving at the same frequency.

I'm suspecting an aerodynamic influence (vortex shedding) on the tires that is generating this movement.  Couple that with the large mass of the tire/wheel combination, the long arm of the gear leg, and it's easy to see how a shake can develop.

One suggestion I've seen is to put a hub cap on the wheel to smooth the airflow around the cylindrical wheel. Any other ideas besides checking the wedges on the gear attach points?

 
All you people with vibration in flight try checking the security of your wedges,the most important ingredient of the recipe for a 180/185.
 
I've flown my plane with 8.00's, 8.50's, 26's, 29's, Airglas 3000 straight skis, and Fluidyne 3600 hydraulic skis w/ 8.50's, and never felt any vibration of the main gear in flight. In my experience, with regard to main gear equipment, size doesn't matter.

Stewart
 
Ive noticed that the bigger the tires, the more wobbly the gear gets during flights.
 
i developed a vibration after installing 8.50's
did not have it with 8.00's
 
Was wondering if anyone notices main gear vibration during flight? I notice mine shaking every once in a while sometimes more than other times. Anyway to cure this?

Dave
 
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