REFLECTOR: Shimmy Damper Settings

Thu Sep 19 14:40:42 CDT 2013

Glad it works for you  so many ways to fix the Challenges. Mine is a FG 
so my settings are not going to be the same for sure.
I agree balanced wheel is a absolute must.  Found that out early on in 
Phase 1.  Damper maybe over kill as I have not tried
lower front wheel settings and have not put in the new bumper.

The big down side for me with the damper is my fairing no longer fits 
and I can not just push the plane out of the hanger
with out being careful of the nose wheel trying to spin 180. :(

Ron

On 9/19/2013 12:48 PM, Bob Jackson (Jax Tech) wrote:
>
> Ron,
>
> We use an old fashioned bathroom 'spring' scale, turn it vertical, 
> reset the zero, and then push it against the back outside/inside edge 
> of the nosewheel tire for the friction settings I described below.  
> Ours is an XL/RG and we fly it about 500 pounds heavier than most XL's 
> -- that may account for some of our use of higher friction settings.  
> We have no trouble taxiing it with the Belleville's set for a breakout 
> friction of ~35 lbs, and very little, if any braking at the start of 
> the take-off run to keep it aligned on the runway.
>
> Using the above spring scales, like I said, I don't see that the 
> damper provides more than 5 lbs of turning friction, and at least with 
> my hand, I can't feel much resistance even to 'impulse hits' with the 
> High Speed setting in CW essentially all the way.  Maybe you just 
> can't apply fast and hard enough of an impulse with your hand to test 
> it...  Still, the damper does provide some turning resistance and 
> we've kept ours set with both Low & High Speed knobs at ~1 turn back 
> from full CW.  No issues with shimmy so far with more than 25 landings.
>
> Bob
>
> ------------------------------------------------------------------------
>
> *From:*reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] 
> *On Behalf Of *Ron N VelocityXLFG
> *Sent:* Thursday, September 19, 2013 8:18 AM
> *To:* Velocity Aircraft Owners and Builders list
> *Subject:* Re: REFLECTOR: Shimmy Damper Settings
>
> When I flew with just the belleville springs I had my front wheel set 
> with 14-16 lbs of pull at the back of the wheel. Were are you measuring
> 35 lbs of pull? Now with the steering dampener I have the springs set 
> to 8lbs of pull . This so far allows me to steer with the winglets on 
> take off.
> That was my main goal for the dampener. Brakes on take of make the 
> take off roll last to long:(
>
> Ron
>
> On 9/18/2013 10:14 PM, Bob Jackson wrote:
>
>> Thanks for the steer, Patrick!
>>
>> I found and read Andy's excellent VOBA article.  Andy did a great job 
>> on the article.  It was very informative and included his 
>> modifications and settings:
>>
>>   * Replace the shear pin with the much stronger one Jorge Bujanda
>>     found (from McMaster Carr and described in Andy's VOBA article)
>>   * Set the damper Low Speed valve -- 1 1/2 turns back from full CW
>>     'Hard'
>>   * Set the damper High Speed valve -- 1 turn back from full CW 'Most
>>     Sensitive'
>>
>> But what Andy didn't discuss was the relationship between his 
>> settings of the Scott's Damper and the old Belleville washers.  When 
>> I measured the nosewheel 'break-out' force required to just begin to 
>> turn the nosewheel (with no Belleville washer tension) and the Damper 
>> set as Andy describes above -- the 'break-out' force was only 5-10 lbs.
>>
>> Prior to adding the Damper, we used to set our Belleville washer 
>> tension so that the nosewheel break-out resistance to wheel turn was 
>> about 35 lbs.  I know Andy said that the value of the Damper was in 
>> it's resistance to high speed or 'impulse' shocks, but I'm skeptical 
>> that the Damper alone will provide enough resistance and damping to 
>> prevent shimmy from these impulses.  My inclination would be to 
>> continue to use the Belleville washers, still tensioned to provide 
>> something very close to the 35 lbs break-out force resistance, along 
>> with the Damper as in Andy setup, or even a little 'harder' and 'more 
>> sensitive'.
>>
>> -- Andy -- if you're monitoring the Reflector -- could you please 
>> comment on my conclusions above, and also describe how you're setting 
>> up the Belleville washer tension in conjunction with your Damper 
>> settings.
>>
>> Thanks,
>>
>> Bob Jackson
>> N2XF
>>
>> ------------------------------------------------------------------------
>>
>> *From:*reflector-bounces at tvbf.org <mailto:reflector-bounces at tvbf.org> 
>> [mailto:reflector-bounces at tvbf.org] *On Behalf Of *Patrick Sieders
>> *Sent:* Friday, September 13, 2013 4:00 PM
>> *To:* 'Velocity Aircraft Owners and Builders list'
>> *Subject:* Re: REFLECTOR: Shimmy Damper Settings
>>
>> There was an excellent write up on the shimmy dampener on the VOBA 
>> newsletter written by Andy Millin.
>>
>> Great article !
>>
>> Patrick
>>
>> Patrick & Dana Sieders
>>
>> 7244 Sugarloaf Drive
>>
>> NashvilleTN 37211
>>
>> Tel. 615-250-2304
>>
>> Cell P. 615-918-2698
>>
>> Email. Js3201 at comcast.net <mailto:Js3201 at comcast.net>
>>
>> Http://www.sieders.com/sieders
>>
>>
>>
>>
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