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  #61  
Old 07-03-2007, 10:44 PM
Bryan Wood's Avatar
Bryan Wood Bryan Wood is offline
 
Join Date: Jan 2005
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Having just re-read the study I'm sitting here in amazement. The results are exactly in line with what my father-in-law and two of his friends described when I had my parking incident. Folks the NTSB nailed this! One of the things that stood out to me when looking at the report was that the tire pressure was unknown on my plane. Well the fact of the matter is that the old wheel pant mounting brackets were such a pain in the @$$ that the nosewheel had to be pulled in order to put air into the nosewheel tire. Pulling the cap off of the front of the nosegear fairing didn't allow enough room to check or add air and I hadn't drilled a large hole in the rear half of the pant to allow easy access. Because of this when I would finally go thru with this process the pressure was usually down around the 20psi range. I'd be willing to concede that the pressure was most likely in this range when I hit the tie down. Another thing that is noteworthy is my nose gear leg fairing was snapped at the top! This wasn't mentioned in the report possibly because they didn't know about it. I hadn't posted pictures of this broken item. Right where the gear leg fairing exited the intersection fairing on the bottom of the cowl the the gear leg fairing snapped from the bending way up at the top. This has been sitting in my hanger for a year and a half but just got tossed a couple of weeks ago. I wish I still had it so that a couple of more pictures could be shared. Another thing that seems crazy is the lack of any drop of the nose when my gear flexed back. From inside the airplane there was no indication that the trailing edge of my wheel pant almost hit the bottom of the cowl. There was a noise, but again no sensation that would indicate what had happened.

So now that some time has passed and the plane is back in form I guess having this happen was actually a positive experience. While it wasn't fun to have to upgrade to the new fork and mounting brackets for the wheel pant the plane is now better and safer for having done it. It also looks like posting the details helped at some level to get to the bottom of all of this.

Oh yea, I love my RV and I still land on grass.

Regards,
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  #62  
Old 07-03-2007, 11:47 PM
chunt0 chunt0 is offline
 
Join Date: Oct 2005
Location: Canton, MI
Posts: 76
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Bryan, thanks for having the courage to tell us your tire pressure was probably low. That's one problem all concerned can fix immediately. Yes, I know it's theoretically possible for a tire to deflate after preflight, but low pressure is a risk factor we can largely control.
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  #63  
Old 07-05-2007, 12:33 AM
koda2 koda2 is offline
 
Join Date: Mar 2007
Location: West Texas
Posts: 282
Default Finally, some science

Craig, thanks for posting the NTSB results.
If you filter out all the emotional bravado, and the negative comments made on this thread, there is some really helpful info here on a number of things including good pilot technique. Also, finally some science and a real look at this issue.
I agree that the NTSB deserves strong commendation for their report. What they did took some hard work and analysis. It also clearly underscores a couple of things.
One, as is the case in a number of scientific disciplines, the experience of one individual, no matter how extensive (4000 landings on 2000 grass strips, etc.), may not always provide the correct information. You have to systematically look at a number of mishaps or events.
Two, this study definitely shows that there is a tendency, under certain conditions for the Van's designed nose gear to act in a seemingly predictable, negative way (notice I didn't use the word "problem"). Obviously, more analysis, and maybe finding other cases to examine, is needed, but hopefully, we can step away refusing to admit there is something going on with the -A nose gears and stop dismissing it as a lot of unskilled pilots out there. Perhaps the changes Vans has already made or the modifications suggested by other builders are all that is needed to make grass or unimproved strips more safe.
Dave A.
RV-6A QB
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  #64  
Old 07-05-2007, 07:43 AM
justinmg justinmg is offline
 
Join Date: Mar 2007
Location: UK
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Quote:
Originally Posted by whirlpool
Bob has posted: the new series gear has not failed- where is the data to support this? Did I miss it?O.K. just my .02 please no flames needed!! ED
The discussion continues thread after thread, but this is the real issue.....Has a mark II fork had an incident yet? I have asked the question repeatedly, with no one having knowledge of a confirmed incident.

It is difficult to produce data for the apparent absence of an event.

However I consider no news to be most definitely good news.

Until that point, complaining about the old (and clearly sub-optimal) design is pointless. Unless I am missing the point .
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  #65  
Old 07-05-2007, 08:36 AM
AlexPeterson's Avatar
AlexPeterson AlexPeterson is offline
 
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Location: Maple Grove, MN
Posts: 2,334
Default New Fork design

I would guess that there are only a few percent of RV trikes with the new fork design.
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  #66  
Old 07-05-2007, 09:09 PM
Captain Avgas Captain Avgas is offline
 
Join Date: Oct 2005
Location: Melbourne, Australia
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Default Amost certainly 100% record.....to date!!!

Quote:
Originally Posted by justinmg
The discussion continues thread after thread, but this is the real issue.....Has a mark II fork had an incident yet? I have asked the question repeatedly, with no one having knowledge of a confirmed incident.
Justin, of course it's a very salient question.

It is thought that Vans designed the new MK2 fork (increased rake and clearance) in late 2004 and issued a bulletin on March 10, 2005, declaring that it was being shipped in Finishing Kits.

It might be expected therefore that there will be a reasonable number of RVs (presumably mostly QBs) that are now flying with the MK2 fork. A number of other flying pilots have chosen to retrofit it.

I have been monitoring the RVA nosegear collapse saga very closely for a number of years. Specifically I have monitored virtually all of the major RV forums including the RV Aircraft Builders Group, RVSQN (UK), VansAirforce, Matronics RV Group, RVs_in_Aus (Australia) and Rivetbangers.

To the best of my knowledge there has not been one report of a gear failure involving the MK2 nosegear. Many of the failures reported resulted in photos being published.....again, every published photo has been of a MK1 (old fork rake) nosegear.

The recent (famous for it's pix and video) Croft Farm accident was certainly a MK1 nosegear.

And all of the identifiable nosegears in the photos provided with the recent NTSB report are also MK1.

I would be confident at this stage that no MK2 nosegear has collapsed to date. I would be further confident that it will become public knowledge IMMEDIATELY that one DOES fail.....given the publicity surrounding this issue.

It is too early to draw firm conclusions on the improved action of the new fork, but the early indications are promising. Although there only a modest number out there, you can't do better than 100% success at this time. After all, as the NTSB report has clearly identified....ground clearance is the name of the game....and the MK2 has more of it....so it is logical that it should produce less 'dig-in' failures over time.

My only question is: Why didn't Dick VanG increase the rake, and therefore the ground clearance, even more than he did. After all, many free castoring designs have a significantly higher rake than the Vans MK2. I suspect he could have easily put at least another inch of clearance under the front nut without any problems. Actually, subsequent to the NTSB analysis, I suspect that he might now be thinking that too.
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RV7A

Last edited by Captain Avgas : 07-05-2007 at 09:23 PM.
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  #67  
Old 07-06-2007, 08:02 PM
mgaffney mgaffney is offline
 
Join Date: Jul 2007
Location: xxxxxxxx
Posts: 5
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First flight was 7/14/02 on my RV6A. It was also the first RV that I had ever flown in (not smart but unbelievable fun). On my second landing I over flared and basically stalled it some distance above the runway. After it was all said and done the G meter read 4 and the top of my head hurt but I was still standing on three legs. I've spent a lot of time on short grass strips and have had to use the breaks hard. I've had to fix my front wheel pant because I hit a shallow drainage ditch that the owner of a grass strip forgot to tell me about. I?ve land on very soft fields where it took ? power just to get it to start rolling after I stopped (looked ok from the air). I even landed with a flat tire (zero pressure) on the nose wheel. This was on concrete and I could tell something was not right. It did not pull to either side so I just gave it some power and drove it on the mains until I got as close to the turn off as I could. I now have 578 hours on the plane and based on my experiences as long as you don't bury the nose wheel in a whole to the point where the fork impacts the ground it's going to stay up.
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  #68  
Old 07-07-2007, 08:16 AM
BrickPilot BrickPilot is offline
 
Join Date: Jul 2006
Location: Lehi, UT
Posts: 90
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Quote:
Originally Posted by mgaffney
First flight was 7/14/02 on my RV6A. It was also the first RV that I had ever flown in (not smart but unbelievable fun). On my second landing I over flared and basically stalled it some distance above the runway. After it was all said and done the G meter read 4 and the top of my head hurt but I was still standing on three legs. I've spent a lot of time on short grass strips and have had to use the breaks hard. I've had to fix my front wheel pant because I hit a shallow drainage ditch that the owner of a grass strip forgot to tell me about. I?ve land on very soft fields where it took ? power just to get it to start rolling after I stopped (looked ok from the air). I even landed with a flat tire (zero pressure) on the nose wheel. This was on concrete and I could tell something was not right. It did not pull to either side so I just gave it some power and drove it on the mains until I got as close to the turn off as I could. I now have 578 hours on the plane and based on my experiences as long as you don't bury the nose wheel in a whole to the point where the fork impacts the ground it's going to stay up.
Sounds like you've been extremely lucky, but I wouldn't bank on that continuing if you push the odds like you've been.
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  #69  
Old 07-07-2007, 12:24 PM
apatti apatti is offline
 
Join Date: Dec 2005
Location: Middle Georgia
Posts: 654
Default PLEASE...

I am really enjoying the discussion about potential modifications to the nose gear design that might improve safety margin. Can we please reserve this thread for that purpose??? I would really hate to see it morph into yet another "taste great, less filling" debate about pilot error vs. design problem. So, PLEASE, if you want to argue that point, use one of the other umpteen threads or create your own new one.


Thanks,
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RV8A
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Warner Robins, GA
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  #70  
Old 07-10-2007, 02:14 PM
DSmith DSmith is offline
 
Join Date: Feb 2006
Location: Panama City Beach, FL
Posts: 129
Default Van at Oshkosh & the A Model Study

Will some of you lucky folks going to Oshkosh see if you can find out if Van is looking at any changes to the nose gear since this NTSB study is now out? I have the original 7A gear and plan to go to the new current setup but I think I'll wait a few months to see if anyone finds the golden fix or Van makes another change! I'm working on my windshield and will be hanging the engine on it soon. Wiring and avionics are finished so it's starting to look like an airplane! Yahoo!

Danny
N625DB
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