REFLECTOR: For Your Information -- Velocity Gear Fork

[Velocity Aircraft Owners and Builders list]

  A welded Fork Might be in order for safety.

Ron

On 6/20/2014 7:33 AM, Velocity Aircraft Owners and Builders list wrote:
>
> This topic was posted to the VOBA forum earlier this week with a lot 
> of discussion. It's important enough to re-post on the Reflector for 
> those who may not be VOBA members.
>
> Note: at the end of this message Andy is looking for other owners who 
> may want to buy a stronger nose wheel fork. By ordering them at the 
> same time, we can save a lot of production cost.
>
> *Reiff Lorenz, Dayton, OH*
>
> Velocity XL-RG, 59% complete
>
> Currently working on: Mounting the electric fuel pump.
>
> *Sent:*Wednesday, June 18, 2014 1:02 PM
> *To:* Main Forum
> *Subject:* [VOBA Forum] For Your Information -- Velocity Gear Fork
>
> In the interest of sharing information within the Velocity community, 
> I want to make builders and owners of flying Velocities aware of two 
> recent nose gear fork failures experienced by me and by John 
> Youngblood.  We are both back flying with replacements of the current 
> nose gear fork design, but want to apprise the community of the 
> potential development of a new, upgraded nose gear fork.  First, a 
> description of the two nose gear fork failures:
>
> *Gear Fork Failure N114MV -- Andy Mllin XL/FG*
>
> **
>
> **
>
> August 7th, 2013; shortly after Oshkosh.  A routine flight was 
> completed, the landing was normal;  touch down on the mains, rolled 
> for a bit and let the nose down.  When it touched it didn't feel 
> right.  It was mushy and the nose started to wobble.  It did not feel 
> like shimmy.  It wobbled a couple times, and then veered to the left.  
> The right brake was applied to compensate.  The nose dropped six 
> inches with an audible crunch.  The plane skidded down the runway.  
> The brakes were applied hard and the airplane was kept close to the 
> centerline.
>
> The gear fork failed catastrophically.  It was broken into three 
> pieces. The wheel was captured by the wheel pant.  It did not go 
> through the prop.
>
> The primary failure was through the thickest part of the casting.  The 
> crack did not follow any visible stress riser.  It did not intersect 
> the gear strut hole.  There was no obvious origin point for the break.
>
> This fork was previously installed on the factory trainer.  It was 
> used during the development and testing of the hydraulic shimmy 
> damper.  When the development and testing was complete, the trainer 
> fork was sent to me along with his damper already installed.  The 
> complete setup was installed on N114MV.  It was on the plane for the 
> first flight.
>
> The plane was flown for 8 months without a nose wheel pant.  On the 
> first flight with a wheel pant, the damper pin sheared resulting in a 
> shimmy.  A new, harder, pin was installed and the plane was flown for 
> another five months without a wheel pant.  The wheel pant was 
> reinstalled and the fork accumulated 30 takeoffs and landings before 
> it failed.
>
> In the 16 months the fork was used on N114MV it did not experience a 
> "nose first" or other notably hard landing.
>
> *Gear Fork Failure N568Y -- John Youngblood XL/RG*
>
> March 10, 2014. While attempting to land in variable wind conditions 
> in Arizona (AWOS reported 6 kt gusts), the canard stalled over the 
> runway and the nose of the airplane dropped.  When the nose wheel 
> struck the fork split in two places.
>
>  The splits were on either side of the main boss on top of the fork. 
> The fork arms and nose wheel departed the airplane.  The plane came to 
> a skidding stop on the bare nose gear strut.  Ground observation of 
> wind gusts was 0 - 20 kts.
>
> Five years prior, while landing at Sun-N-Fun, the aircraft suffered a 
> violent shimmy (nose landing gear fiber lock nut was loose after 
> tightening two flight segments prior).  The aircraft was inspected by 
> the factory people and no crack or problem was found.  On the trip 
> home John made a stop in Missouri.  During roll out in Joplin, the 
> gear leg failed.  The gear leg was replaced and the plane was flown home.
>
> The new gear leg and original fork have been in use since.
>
> The surface of the gear fork had been polished.
>
> Both forks had years of use.  One was FG one was RG. Both forks had 
> experienced shimmy.  Both failures were sudden and without warning.  
> Both pilots feel fortunate there were no injuries and damage was 
> localized to the landing gear.
>
> These are the only known Velocity XL gear fork failures in the fleet. 
> Both failures have been discussed with Scott Swing.
>
> The pieces from my fork were shipped to the factory for inspection. 
> This information has also been shared with other Velocity owners and 
> builders.
>
> Scott Swing has been very helpful.  Both forks had experienced shimmy 
> and at least one very hard landing.  Scott is confident in the current 
> fork.  He understands the failures are personal for John and me and he 
> appreciates our desire to have an even stronger fork.
>
> Richard Cano is flying with a fork milled from billet.  In general, a 
> billet fork will be stronger than a cast fork. Scott Swing suggested 
> 7075 alloy be used.  We are in the process of developing a replacement 
> milled from billet.
>
> When we get closer to producing a fork, we may open the purchase to 
> the community. It would be helpful to have an idea of how many 
> builders and owners would be interested in purchasing the upgraded 
> fork as that would likely impact the cost.
>
> The Velocity factory is not recommending you replace your fork.  I am 
> not recommending you replace your fork.  This has been provided only 
> for your information and consideration.  If you have experienced a 
> shimmy or have a concern about your fork, Scott has indicated he will 
> be available to answer questions.
>
> /Andy Millin /
>
> /amillin at sbcglobal.net 
> <mailto:amillin at sbcglobal.net?subject=re:For%20Your%20Information%20--%20Velocity%20Gear%20Fork>/
>
>
>
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