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09-04-2012, 12:44 PM
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Join Date: Aug 2010
Location: Marshall TX (KASL)
Posts: 1,783
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I am understanding why grass strips will be more bumpy and have more vertical loading potential. I am not understanding why braking on grass vs paved is different and would create more fore-and-aft flexing in the gear. Can someone explain? I am putting in a (short) grass strip for use next year.
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09-04-2012, 12:48 PM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Quote:
Originally Posted by Mich48041
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And page 17-1 details the process.
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09-04-2012, 01:22 PM
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Join Date: Oct 2010
Location: La Feria Texas
Posts: 3,822
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I have come to pretty much the same conclusions with the little information we have so far.
Of note however, one plane with the cracks in the center channel, has never once landed on a grass strip!
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09-04-2012, 01:46 PM
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Join Date: Dec 2005
Location: San Pedro
Posts: 1,013
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OK - a request
I am not any kind of engineer not have I slept in any hotel or motel for a few year or so - but it is clear to me that there needs to be an improvement made to the fuselage structure of the RV-12.
I would like Van's to take a proactive approach to this obvious problem. Surely someone at the Van's engineering department could figure out a fix for this 'problem'. Maybe an internal doubler?
As one who has not yet built the fuselage, I would like to see Van's offer me some sort of beef-up for the main landing gear area that I can install as I build my fuselage or do ?????
And leaving those who have experienced this type of bent skins are currently left to their own devices to try to 'fix' the damage. No matter how the fuselages were 'bent', it would be good if Van's could suggest ways to 'fix' the damage.
I think that it is a safe bet that there are other RV-12s out there that are flying that have suffered the same result of some sort of landing or breaking 'incident'. Not all RV-12 owners have ever heard of the VAF and many have not ever pulled their wings off for whatever reason.
I am not a better pilot than those who have suffered this type of damage so I need a 'fix' that I can include into my build.
This is a plea for Van's to make the RV-12 better and safer. This, I hope, will happen before the 'regulators' ground the RV-12 fleet.
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09-04-2012, 03:04 PM
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Join Date: Jan 2005
Location: Sherwood, Oregon
Posts: 981
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Quote:
Originally Posted by E. D. Eliot
This is a plea for Van's to make the RV-12 better and safer. This, I hope, will happen before the 'regulators' ground the RV-12 fleet.
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Let's don't assume that Van's "officially" monitors this forum just because one of their employees does. Best to ask that kind of question directly to them. A registered letter might be more effective than email in getting their attention.
I've heard more than one of Van's people referring to VAF as "chatter". In a perfect world I would think it would be helpful to Van's and us if they would monitor VAF as a source of their customers' thoughts and/or concerns, we all might learn something.
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__________________
Jerry Cochran
Sherwood, Oregon
RV-7a 707DD Bot from David Domeier 12/01/11
Lycoming IO-360 Catto 3 blade Panel upgrade in progress
RV6a 18XP 1st flite 03/21/07 sold to Dale Walter 10/22/2011
Superior IO-360, Hartzell Blended, GRT/Dynon
Happily "autopaying" DR
"Suppose you were an idiot, and suppose you were a member of Congress; but I repeat myself."
Mark Twain
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09-04-2012, 04:14 PM
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Join Date: Jan 2005
Location: Arlington, TX (DFW)
Posts: 1,164
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Quote:
Originally Posted by E. D. Eliot
I am not any kind of engineer not have I slept in any hotel or motel for a few year or so - but it is clear to me that there needs to be an improvement made to the fuselage structure of the RV-12.
I would like Van's to take a proactive approach to this obvious problem. Surely someone at the Van's engineering department could figure out a fix for this 'problem'. Maybe an internal doubler?
As one who has not yet built the fuselage, I would like to see Van's offer me some sort of beef-up for the main landing gear area that I can install as I build my fuselage or do ?????
And leaving those who have experienced this type of bent skins are currently left to their own devices to try to 'fix' the damage. No matter how the fuselages were 'bent', it would be good if Van's could suggest ways to 'fix' the damage.
I think that it is a safe bet that there are other RV-12s out there that are flying that have suffered the same result of some sort of landing or breaking 'incident'. Not all RV-12 owners have ever heard of the VAF and many have not ever pulled their wings off for whatever reason.
I am not a better pilot than those who have suffered this type of damage so I need a 'fix' that I can include into my build.
This is a plea for Van's to make the RV-12 better and safer. This, I hope, will happen before the 'regulators' ground the RV-12 fleet.
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Amen! There are too many instances of this problem that we now have documented, to simply say 'there isn't really a problem'. There obviously is something going on. Whether the damages have shown up on the factory demonstrator or not, that proves nothing. We are seeing photgraphic proof that there is indeed an issue that should be addressed. To everyone who has had these issues, PLEASE send in the forms to Van's as suggested earlier. I am about to start on my fuselage and would like to be able to build in the fix (if Van's suggests one). I could see us (or Vans, for that matter) shrug off one or two incidents as bad landings, etc. But to have this many documented cases already showing up? Not good. And ya'll are right...there are certainly a LOT of -12 drivers out there that probably don't even know this forum exists. As an example, I met a customer of mine last week, who lives in Dallas. He's a pilot for SWA and has an RV-4 and an RV-8. He had no idea what I was talking about when I mentioned the VAF forums.
PLEASE send in your documentation forms to Vans!!!! This issue isn't going to fix itself, and my goodness, replacing those bad areas of the fuselage? That looks like a major major project.
Thanks-
__________________
Gary Robertson
Arlington, TX
RV-12 Built / Sold / Flying
Currently Flying: Cessna Skyhawk 172
Rebuilding a true barn find J-3 Cub
Last edited by txaviator : 09-04-2012 at 04:16 PM.
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09-04-2012, 10:07 PM
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Join Date: Jun 2008
Location: Byron Bay, NSW
Posts: 104
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Dont hold your breath
I have followed a number of issues that vans has taken action on and there is a pattern , to me anyway.
In the ruptured fuel tank saga, nothing official was heard from vans for months. People reported encouraging comments made in conversations with vans staff. Eventually they came out with a fix, that is optional by my reading of the information
In the Creeping throttle problem, Vans to my knowledge issued no official fix. But I talked to staff at McFarlanes and they reported that Vans worked with them to design weaker springs that are now available from Mc Farlanes if you ask for them.
With the loose engine mounting bolts fault, Vans responded in record time with a mandatory official fix.
The pattern I see is Vans admitting nothing officially; leaking a few encouraging comments; at the same time beavering away as fast as possible to diagnose, design and test a fix; then announcing it in a way to have the least adverse affect on the product reputation
The only objection I have to that is we dont know if they are listening. Surely every report of an issue deserves acknowledgement of its receipt. Do they acknowledge?
In todays letigious world, I see Vans response as reasonable in most respects. The are not going to acknowledge a problem without a clear path to the next steps required.
So the best we can do is make sure damage to aircraft is formally reported. That report will help you too when it comes to who is to pay up for repairs from a faulty design
My hope is that Vans engineers are rapidly acquiring a -12 fuse to do load tests on, and sort out if it is the brakes, the bending moment over the MLG channel or whatever
Rod
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09-05-2012, 06:11 AM
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Join Date: Nov 2008
Location: Gloversville, NY
Posts: 1,587
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I have been away from aviation for a few days to address some unrelated issues. Yesterday I got to my hangar long enough to inspect my airplane. Thankfully, no cracks, no buckled skins, no crimped brake lines. 130 hours, no hard landings, no hard braking, some grass fields.
Having reported that, let me say that I am encouraged by the change in tone of this thread. Most contributors now seem to be saying what I tried to say in my (perhaps poorly worded) post of a few days ago, and that is that the most effective way for the community to encourage Van’s to address these incidents is to notify them directly via official channels, and not depend on one of their employees reading this thread on VAF.
I fervently hope all nine, or whatever the number is, of folks who have experienced skin wrinkles or gear mount bolt hole cracks have submitted the official reports with as much factual detail as possible. How else can Van’s engineering staff analyze the situation and engineer a fix?
My thanks to all who are trying to contribute in a constructive way. Without diminishing their efforts, I must point out that there is a risk of the forum being perceived as an official reporting source, which would bypass the direct contact with Van’s. Everyone who has seen this problem, or something similar, should be encouraged to make direct contact with Van’s engineering department via the channel that has been provided us.
__________________
John Peck, CFII, A&P, EAA Tech Counselor, Flight Advisor.
?Master Pilot? Award, UFO Member.
RV-12 N37JP 120176 Flying since 2012.
One Week Wonder Build Team, OSH 2018.
VAF paid through 10/2019.
Last edited by BigJohn : 09-05-2012 at 06:31 PM.
Reason: Added statistics.
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09-05-2012, 06:35 AM
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Join Date: Mar 2008
Location: Texas
Posts: 1,378
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Of course every RV12 driver/builder does not read VAF but I do. One of the reasons I do is this very issue...I get to hear about potential problems before the factory sends me a letter. I would almost bet we all ran out and checked our own channel after seeing several pics. I do not have the cracks or wrinkles and I seriously doubt if it comes from grass (why would it?). I am not talented enough to avoid making a mistake now and then but one thing I do consistently is to land the plane as slow as it will allow...which is pretty darn slow. It not only minimizes the energy transfer at impact, it allows for some outstanding crosswind landings...by the time you touch town (whatever the wind) you are all but walking. We all know a 600ft/min impact will pull the channel back like a sardine can and that a 40 knot touchdown is barely noticeable. Until there is a definitive answer, which there will be, I would practice my full flap, coordinated stalls at altitude (a real stall, not just a horn) and find a comfortable touchdown speed that is well below 60 or 70 knots.
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09-05-2012, 06:57 AM
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Join Date: Feb 2005
Location: Huskerland, USA
Posts: 5,862
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Quote:
Originally Posted by Peterk
Of course every RV12 driver/builder does not read VAF but I do. One of the reasons I do is this very issue...I get to hear about potential problems before the factory sends me a letter. I would almost bet we all ran out and checked our own channel after seeing several pics. I do not have the cracks or wrinkles and I seriously doubt if it comes from grass (why would it?). I am not talented enough to avoid making a mistake now and then but one thing I do consistently is to land the plane as slow as it will allow...which is pretty darn slow. It not only minimizes the energy transfer at impact, it allows for some outstanding crosswind landings...by the time you touch town (whatever the wind) you are all but walking. We all know a 600ft/min impact will pull the channel back like a sardine can and that a 40 knot touchdown is barely noticeable. Until there is a definitive answer, which there will be, I would practice my full flap, coordinated stalls at altitude (a real stall, not just a horn) and find a comfortable touchdown speed that is well below 60 or 70 knots.
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And lay off the hard braking. 
__________________
RV-7 : In the hangar
RV-10 : In the hangar
RV-12 : Built and sold
RV-44 : 4 place helicopter on order.
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