WD-1230 Nose Fork cracks

Before I begin this thread let's look back at another thread call, "Flying Technique". The thread discussed suggested takeoff techniques and took off like a rocket with lots of debate over the lifting the nose of the RV12 as soon as possible for better control in a cross wind. Well I'm going to show you another reason for using what I like to call the, "Modified softfield takeoff and softfield landing Technique". Lower maintenance and less stress on the WD-1230 Nose Fork and the tubular Nose Strut.
The Scenario!
RV12 First Flight June 2010. Total time airframe 558 hours. Plane used extensively in transition training. Hundreds of takeoffs and landings. Vans has been notified and has seen the pics.
Observations!
IMHO there is no flaw in the design, just what you would find in a training environment. The info posted here is for other RV12 pilots to think about and watch for if they let their nose wheel plop down over many many landings versus holding the nose off as in a SoftField landing and continuing to hold the nose wheel off as long as possible until Horizontal Stab lift is loss due to low airspeed on roll out. Again this technique for both Takeoffs and Landings will make for less stress and lower maintenance over the life of the Aircraft. Also think of the damage that would occur to the Aircraft if this had not been found prior to complete failure. Furthermore I recognize that in certain weather conditions that this technique may not be feasible.
You make the Call
Front top right side of nose fork.

Lower front right side of Nose Fork. Ruler included in pics for scale.

Any particularly hard landings you recall, or do you think this was cumulative? Glad you caught it early, could have been a nasty surprise on the landing roll! Another item to add to the CI checklist. Thanks for sharing.

A rut caught while taxiing might cause this. Thanks for posting John.

Hard landing

BigJohn said:

Any particularly hard landings you recall, or do you think this was cumulative? Glad you caught it early, could have been a nasty surprise on the landing roll! Another item to add to the CI checklist. Thanks for sharing.

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I'm afraid I remember one harder landing than desired, during transition training with John in January. ... sorry John I really hope it wasn't a result of our couple of days flying.

PilotBrent said:

I'm afraid I remember one harder landing than desired, during transition training with John in January. ... sorry John I really hope it wasn't a result of our couple of days flying.

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Not to worry my friends this is cumulative over many many cycles in a training environment. I do lots of extra inspections on my gear on a regular bases. Thats why I went with the sealed bearings mod on my main gear to reduce maintenance. Just wanted to make everyone aware of the long term things to look out for. The cost of the new fork is $196.00 which is not bad if kept in perspective compared to a factory built airplane. And the labor is only about 2 hour to remove and install the new one. Could you imagine what that part would cost for a DA20.

Good info John. Thanks for posting.

Definitely a specific item on my annual list now. Thanks for posting the info.

From the pictures It looks like there are two cracks at different locations correct?

In the bottom photo, right where the crack is, it looks like the metal wasn't radiused to match the rest of that edge. A stress riser situation? Or maybe the crack tweaked the metal out so it just appears that way?

WingedFrog said:

From the pictures It looks like there are two cracks at different locations correct?

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Correct, there are two cracks. One on the lower right side of the fork. The other one is above that lower crack in the upper edge weld.

rightrudder said:

In the bottom photo, right where the crack is, it looks like the metal wasn't radiused to match the rest of that edge. A stress riser situation? Or maybe the crack tweaked the metal out so it just appears that way?

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The new part will be here late next week. When I remove the old fork Ill post some more Pics and Ill check on the Radius.

Sorry to hear about your troubles since I probably know of a couple pilots that contributed to the issue.

We thoroughly checked-out ours today and see no issues.

Wondering if variations in tire pressure could help lessen the potential for such issues. Maybe just unavoidable if the welds just aren't perfect from the factory.

In any event, good luck with your repairs.

WD-1230 Nose Fork Failure

On 4/15/16 I used my tow bar to hangar my RV-12. I noticed that the tow bar was tilted as I chocked the wheel. I removed the wheel pant and saw large cracks in the same locations on the right fork as Jetguy's postings. My cracks were so large that the top of the tire was rotated several degrees to the pilot's side of the aircraft. Is it a coincidence that all of the cracks that have been reported (that I am aware of) are in the right fork welds of the nose fork assembly? I haven't had my structures guru look at failure but will post his opinions later.

Bob Kibby, RV-12 N712BK 291 hrs 478 Lndgs