NEW V/S Modification video Anti-Splat-Aero - Page 3

Snowflake · #21 11-13-2012, 12:48 AM

Quote:

Originally Posted by PerfTech

...We were well aware of this accident and as stated before, this tail didn't fall off. It was sheered in half from surface flutter caused by balance issues and over speed. This plane was seeing speeds well over 280 MPH and recorded dives in excess 12,000 FPM. This is far and away beyond the design limits of this airplane and the outcome is predictable and pretty much what Vans cautions can happen. This failure is in no way even related to the subject of the V/S mounting bracket or the modification we are offering. Thanks , Allan...l

While I don't disagree with your conclusions regarding the accident, to say that "the tail didn't fall off" and the failure is "no way related" is quite a stretch.

The photos of the wreckage (not included in the initial TSB report but are included in the other reports that are available if you ask the TSB for them) show that the stock forward bracket held very securely despite the punishing forces that it was subjected to during the course of the accident. In fact, the forward spar failed before any of the stock mounting bracket did.

That leads me to conclude that the stock mounting arrangement *is* strong enough, when properly installed. As an aside, looking at the photos of the mounting bracket in the C-GNDY accident, there's some hinky rivet pattern going on there, that doesn't use all of the rivet holes... No idea why. Still, the part didn't fail.

Here is the relevant page from the more in-depth document:
http://www.b4.ca/temp/output.pdf

As your modification merely strengthens this existing bracket, doesn't it just reinforce the stress concentration that already exists at the end of the bracket?

PerfTech · #22 11-13-2012, 09:35 AM

...This thread seems to be wondering off from our original intention. We saw a problem with this original bracket and in our estimation have solved this problem. If it is your opinion that the original is adequate for your purposes then do not change it. Many people appear to feel as we do and have elected to do this simple modification. We are currently setting up our laser to do a second run of these parts, as the first fifty of the nines were sold in twenty four hours. We currently have orders for even more of the seven and eight modification brackets that will be available soon. I made a mistake commenting on the incident in Canada and it is irreverent to what we are trying to do with this mod. That failure obviously was not caused or effected by this bracket so it is of no issue here. Thanks, Allan..

pmccoy · #23 11-13-2012, 01:23 PM

Alan-

Interesting product. I had not seen any of the post regarding the possible cracks forming on this bracket.

Can you or some one else post a link to one of the older post please. I would like to see what the guys are saying who have seen this issues. Thanks.

Red Five · #24 11-13-2012, 01:43 PM

Quote:

Originally Posted by pmccoy

Alan-

Interesting product. I had not seen any of the post regarding the possible cracks forming on this bracket.

Can you or some one else post a link to one of the older post please. I would like to see what the guys are saying who have seen this issues. Thanks.

Try this one...
http://www.vansairforce.com/communit...ad.php?t=89848

FlyingArcher · #25 11-13-2012, 01:46 PM

http://www.vansairforce.com/communit...ad.php?t=87124

PerfTech · #26 11-14-2012, 11:12 AM

Quote:

Originally Posted by MS19087

You will note that the VANs instructions to install this bracket allows the builder to place the bracket in the back OR the front of the spar depending what fits best. Mine in fact is in the back where I believe it is not subjected to the point pressure that those mounted on the front experience. That said, will this new brace work irrespective of how your bracket is currently installed FRONT or BACK??

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....We want to let you guys know that we have finished the form die and tooling to make the mod for the assemblies that are mounted on the opposite side of the vertical spar. We have had several requests for this one and it seems about 15 % are on the back side. Please be sure to specify when ordering if you require this change (front or rear).
....We would like to say thank you for the fabulous response on this new product. We really appreciate this and all the kind words as well. Regards all, Allan...

snoop9erdog · #27 11-14-2012, 11:57 AM

Allan,

What is your recomendation to coat the new bracket with to avoid any dissimilar metal issues between the AL and SS? Is there a specific reason you went with 301 SS rather than a Chromoly application? Just curious. Thx.

PerfTech · #28 11-14-2012, 10:50 PM

Quote:

Originally Posted by snoop9erdog

Allan,

What is your recomendation to coat the new bracket with to avoid any dissimilar metal issues between the AL and SS? Is there a specific reason you went with 301 SS rather than a Chromoly application? Just curious. Thx.

...This material is a very desirable grade for this type of part. It is very corrosion resistant, very strong, very tough and requires no heat treating to achieve the strength (unlike 4130). If you are concerned about the dissimilar metals, for a little added protection you can apply a thin film of dielectric grease between the two surfaces. I have included below a basic spec. sheet that outlines the general information on this material. It is very widely used in aviation for high stress parts. Thanks for the question. Allan...

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170 driver · #29 11-15-2012, 06:00 AM

The OEM I worked for used this material in structural repairs quite often, the engineering requirements for protective coatings were one coat of epoxy primer and 2 coats of solvent resistant white epoxy paint after drilling and fitting. As far as I know, there were never any corrosion problems with it with this treatment. I'm not sure what treatment I will give the parts I ordered from Allen, but they will be coated. Hopefully I can find some of this primer and paint in small enough quantities to make this happen.

PerfTech · #30 11-28-2012, 10:35 PM

....We now have the V/S mods finished for the RV9s with the mounting brackets attached to the rear of the vertical spar as well as the standard front mounting. Please be sure when ordering to specify the one you need. We will be offering this bracket in both configurations for the 9, 8, & 7s perhaps the 6s if the demand in there Thanks, Allan...