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  #101  
Old 09-03-2012, 02:24 PM
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RDOG RDOG is offline
 
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Default Shadowy Figures

Quote:
Originally Posted by DonFromTX View Post
Good questions John.
How I got in the center of this starts with Ron Russ noting his damage after hearing noises when landing he could not identify. He had grown quite hostile about the mud slinging when something like this is mentioned on VAF, does not do photos, and asked me to post his misfortune for others to ponder. At that time it seemed like a single incident he caused by a hard landing. I did that for him, and for what I considered a favor for other owners who might encounter the same fate. I never wished to become a "clearing house" for this or any other problem. For some reason I don't understand, I then became a "wailing wall" for those who had the same damage and did not wish to post it on VAF (probably for the same reasons that show up in this thread, you will get accused of all sorts of things just for bringing it up, and as you might have noticed, many people have no idea how to post photos on the forum). I never resort to name calling, but those you call "shadowy figures" will have to speak for themselves.
After at least two people tried to bring it to the attention of Vans, and were rebuffed with the old story that the plane is just fine since it met some alphabet standards, it is poor pilots that are causing the problem, and in each case were told "this is the first we heard of this" which was not entirely true, it caused someone to say to me what I quoted as their response. I never said it was MY opinion, I still think the RV12 is the finest LSA out there, bar none - and even if it turns out that the landing gear needs a little stiffener or something. Good grief fellows, did you not know it is an EXPERIMENTAL aircraft?
I never intended this thread to be some statistical refined definition of the problem with readily available solutions, but simply a FORUM where others with similar problems or suggested solutions can communicate. I just don't agree with many that feel that ANY criticism of the RV12 should be swept under the carpet and never ever mentioned publicly. The reporting system that Scott mentioned is perfectly proper for reporting these things to Vans, but it appears it is not widely used, or is not effective in informing other owners. Vans DOES study problems for a solution, we have the fuel tank mod and the nose wheel pant fix as examples. We should be thankful that these solutions are carefully studied and proven before we are informed of a fix. I respectfully disagree that such problems should be kept secret from the rest of the owners as you suggest you will do John, but I can however respect your decision to do it that way.
So, I don't feel I deserve a spanking for sharing information that I felt other owners should be aware of. From some of the responses, one would think I was selling a fix for the problem and promoting the problem. I am selling NOTHING, and if you don't like to hear about a problem, I suggest you not read the posts...
Hey Don don't bring us shadowy figures in to this.
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  #102  
Old 09-03-2012, 02:26 PM
sf3543 sf3543 is offline
 
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Location: San Antonio, TX
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Default Need More Data

In reading this entire thread, it is obvious that there is not enough information presented to begin to make any logical conclusions as to cause.
Don't blast VAN's for not responding until they have the data they need.
Also, VAN's may choose not to even address problems encountered by RV12s built as EAB with different engine, avionics, fuel and loading configurations.
Following are some of my observations, based on information from this thread, plus my own personal observations from my RV12, both before and after the rebuild.
Some of the affected RV12s are EABs with Viking engines installed. (I think I read that the Viking engine weighs 60 lbs more and provides 110 HP, vs the 100 HP provided by VAN's Rotax.)
How are each of the damamged planes configured? (Weight and operation have a definite effect on how a plane holds up.)
Are they ELSA or EAB?
What power plant is installed?
Any other modifications to the airframe?
What was the weight of the plane at the time of the incident? (It is easy to over gross the RV12 with a couple of hefty guys, not to mention a larger engine, extra avionics, etc., that could contribute to an over gross condition.)
Pilot technique. (Pilot competence is a subjective thing, but I have seen pilots slam down their A model RVs so hard I thought something surely had to break and later bragged about their wonderful landing techniques. Just saying!)
Building technique. (As a tech counselor, I have seen a lot of builds. Everything from beautiful to down right unsafe. Some builders don't even debur anything and expect to win awards. So, the quality of the build is an issue that should be considered, especially in critical areas.)
There are probably a few other items that need to be looked at and studied but these are a few.
I really am interested to see the ratio of RV12 ELSA vs RV12 EAB planes that have been damaged and how modifications have played a part, if at all.
I personally believe that the RV12 is designed to be what it is and shouldn't be modified, if you expect it to hold up reasonably well, but that's me. They are EXPERIMENTALs after all, but if you purposely, or accidentally, exceed the manufacturer's design limits, you will likely have problems. However, you can easily exceed design limits by rough handling, as in very hard landings or consistent rough use, as well as by changing equipment. It happens all the time to all kinds of planes.
At any rate, I am interested to see more data, if the owners are willing to provide it, and maybe a little less bickering. Eventually, we will find out what is causing these issues so they can be overcome. Petitioning the owners to fill out their forms for VAN's is probably the best way to get to the bottom of it.
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  #103  
Old 09-03-2012, 02:27 PM
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DonFromTX DonFromTX is offline
 
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Thanks for that contribution, yours is the ninth that I am aware of now. I am sure you will find that in order to go so far back to kink the brake line, when you remove the wings you will see how it got that far back, at least that seems to have been others experience. For others enlightenment posting photos of what you find would be valuable.
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  #104  
Old 09-03-2012, 02:51 PM
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DonFromTX DonFromTX is offline
 
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Very well stated and logical Steve. Only one, the very first example, has the Viking engine installed, all others appear to be Rotax powered to the best of my knowledge (Your indication was plural, but there is only one Viking powered 12 flying in the USA. Well, WAS flying, now grounded for repairs). The elusive thing to this list of information, is that virtually none can trace back to exactly when it happened! At best some recall an unusually difficult landing way back in time, but not a specific incident. The apparent fatigue cracks in the channel were PROBABLY not caused by one incident anyway based on my looking at the cracks. The damaged planes vary from those who only landed on grass, to those that NEVER landed on grass. Getting someone to admit they regularly overloaded their plane is difficult at best.
Quote:
Originally Posted by sf3543 View Post
In reading this entire thread, it is obvious that there is not enough information presented to begin to make any logical conclusions as to cause.
Don't blast VAN's for not responding until they have the data they need.
Also, VAN's may choose not to even address problems encountered by RV12s built as EAB with different engine, avionics, fuel and loading configurations.
Following are some of my observations, based on information from this thread, plus my own personal observations from my RV12, both before and after the rebuild.
Some of the affected RV12s are EABs with Viking engines installed. (I think I read that the Viking engine weighs 60 lbs more and provides 110 HP, vs the 100 HP provided by VAN's Rotax.)
How are each of the damamged planes configured? (Weight and operation have a definite effect on how a plane holds up.)
Are they ELSA or EAB?
What power plant is installed?
Any other modifications to the airframe?
What was the weight of the plane at the time of the incident? (It is easy to over gross the RV12 with a couple of hefty guys, not to mention a larger engine, extra avionics, etc., that could contribute to an over gross condition.)
Pilot technique. (Pilot competence is a subjective thing, but I have seen pilots slam down their A model RVs so hard I thought something surely had to break and later bragged about their wonderful landing techniques. Just saying!)
Building technique. (As a tech counselor, I have seen a lot of builds. Everything from beautiful to down right unsafe. Some builders don't even debur anything and expect to win awards. So, the quality of the build is an issue that should be considered, especially in critical areas.)
There are probably a few other items that need to be looked at and studied but these are a few.
I really am interested to see the ratio of RV12 ELSA vs RV12 EAB planes that have been damaged and how modifications have played a part, if at all.
I personally believe that the RV12 is designed to be what it is and shouldn't be modified, if you expect it to hold up reasonably well, but that's me. They are EXPERIMENTALs after all, but if you purposely, or accidentally, exceed the manufacturer's design limits, you will likely have problems. However, you can easily exceed design limits by rough handling, as in very hard landings or consistent rough use, as well as by changing equipment. It happens all the time to all kinds of planes.
At any rate, I am interested to see more data, if the owners are willing to provide it, and maybe a little less bickering. Eventually, we will find out what is causing these issues so they can be overcome. Petitioning the owners to fill out their forms for VAN's is probably the best way to get to the bottom of it.
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  #105  
Old 09-03-2012, 03:00 PM
dick seiders dick seiders is offline
 
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I have already said what I had to say , but would just like to add that we're all on the same team here gang, and are making progress in spite of us. Maybe we need to lighten up on one another and remember that while we may have small differences in how we contribute we all contribute to moving along to the best conclusion.
Dick Seiders
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  #106  
Old 09-03-2012, 03:09 PM
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DonFromTX DonFromTX is offline
 
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Well rats, there goes my transition training, you will NEVER let me fly yours for fear of breaking something expensive now
Quote:
Originally Posted by RDOG View Post
Hey Don don't bring us shadowy figures in to this.
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  #107  
Old 09-03-2012, 03:58 PM
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Geico266 Geico266 is offline
 
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Default

Just inspected my plane. Let's call her "Geico".

265 hours TT, E-LSA
Removed the wings, no deformation on side skins.
Inspected the gear bolt nuts, no cracks visible.
Inspected brake lines, no deformation.

No "hard" landings, several cross wind landings exceeding 15 MPH. I dip one wing until that wheel touches to stop drift. Doesn't seem to mind side loading.

I would say moderate braking once in a while to make a taxi way. Never wheel hop or skidding, just solid braking in a straight line using both brakes evenly.

Rarely fly off grass.
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Last edited by Geico266 : 09-04-2012 at 06:04 AM.
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  #108  
Old 09-03-2012, 08:34 PM
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DonFromTX DonFromTX is offline
 
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Default One More

I had posted photos of two of the three cracked center channels, here is the third one:
[IMG][/IMG]
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  #109  
Old 09-03-2012, 08:43 PM
mcems mcems is offline
 
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Don

I sent you a private message




Brad Stiefvater
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  #110  
Old 09-04-2012, 06:37 AM
rgmwa rgmwa is offline
 
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Location: Perth, Western Australia
Posts: 1,647
Default Coincidence?

Looking back over the admittedly few reports and photos in this thread it seems that the buckled skin/crushed brake line compression damage has all occurred on the right side of the aircraft.

Have there been any reports of this particular combination occuring on the left side? If not, then it might be reasonable to add the load from a tank of fuel sitting on the right baggage floor to the possible list of contributing factors that others have already mentioned.

One other possible factor in all this is additional back-stick aerodynamic down load on the stabilator early in the landing run. Add in some bounce from a rough surface and some heavy braking and I'm guessing there could be some significant stresses generated on the airframe in that area.

Just some thoughts.
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