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New Firewall Stiffening Kit

T

todehnal

Well Known Member
Anybody installed the new firewall stiffener kit??
Looks like there may be a little touch up painting to do on finished birds.
Is it worth the trouble to install it??

Tom
 
Receivied the kit - -

and yes, there will be some rivets to touchup after this mod. The ones under the wing just don't show much, but these will for sure. I am going to do it when the next oil change is due, which won't be too long.
 
I installed it a few weeks ago on New Blue while I was doing the landing gear SB. It's pretty easy to do, but will require a bit of touch up paint on painted airplanes.
 
Just curious, but I assume this is about PN# 12 STIFFENER KIT? If so then isn't it just a piece of angle that gets riveted to the firewall and out of sight? I'm having trouble figuring out what paint would need to be touched up. I haven't been able to find this kit listed for sale on Van's website yet, but I assume some have been able to order it? On the other hand if this is about something else, just ignore me :confused:
 
Hey Robert - -

there are 4 pieces provided, and rivets. If you have ribs stamped in the lower firewall, you will use 2 of the pieces there. The other 2 go inside under the deck and back along the side skin. Several new holes will be required there. Nothing real hard, but will be drilling and riveting several holes.
 
Ah right! Thanks John. I guess I'd better warm up the old pedal wireless and send Vans an order then. :D
 
Van's will send

The 'kit' free of charge - I got mine a few weeks ago. I didn't have to ask for it - it just came in the mail - a small package about 8" by 5" by 1".

If you need it right away then let Van's know otherwise they just send it to you apparently by lowest kit number first, etc.
 
ED - -

this is a different kit. This one stiffens the right lower firewall. The oil tank mounting is a free kit. This one is $25, and not required. For those of us who have not enjoyed the 'rumbling' noise, it should be a good fix.
 
rgmwa said:
Just curious, but I assume this is about PN# 12 STIFFENER KIT? If so then isn't it just a piece of angle that gets riveted to the firewall and out of sight? I'm having trouble figuring out what paint would need to be touched up. I haven't been able to find this kit listed for sale on Van's website yet, but I assume some have been able to order it? On the other hand if this is about something else, just ignore me :confused:
Click to expand...

I can't seem to find this kit in the web store. How did you guys order this? Phone/email?
 
More than just the firewall stiffener is included...

i-nSjjxg5-M.jpg
 
Partial Install

I did the firewall stiffener today. It was quick and easy. I'm thinking about not doing the two little side wall stiffeners. I have a nice Imron paint job that I just hate to disturb. Since it is an optional mod anyway, I am planning to shelf those parts until a later date. Any Comments??.........Tom
 
Just ordered my firewall stiffening kit from Van's. The lady that took my order chuckled and said "wow, someone must have posted something online recently. Our phones are going crazy with orders for these". :D

Yep, $25 plus nominal freight.
 
txaviator said:
Just ordered my firewall stiffening kit from Van's. The lady that took my order chuckled and said "wow, someone must have posted something online recently. Our phones are going crazy with orders for these". :D

Yep, $25 plus nominal freight.
Click to expand...

Ditto - just called :D
 
Thanks, John

Thanks for the correction, John - and for all or the other posts! I do appreciate your contributions. Would you recommend that I order this kit and incorporate it into my build? I am inclined to do that. Might save having to do it later.
 
Is this just for noise reduction or is there some structural or fatigue issue related to it. The reason I ask is I'm inclined to not mess with my paint unless there is a safety issue.
 
Yes - -

the Stiffener kit is for noise reduction. The other is for possible tank mounting bracket issues.
 
While JB is correct that there is a firewall stiffener in the kit, there is also a pair of reinforcement members for the fuse sides. I believe these members are to beef up that area for landing gear (nose) stresses.
 
Regarding these stiffeners - I wonder to what extent the stiffening is accomplished if the angle (or perhaps a slightly wider piece of thicker angle) is simply attached using pro-seal rather than riveting? I bet for simple oil-canning that would do the job. If I had the issue, I would try that first, at least, before messing up my paint job.
 
Stiffener Mod

I went ahead with the whole mod. It really wasn't that big of a deal. I used a sharpened piece of small tubing, that just fit over and LP4 head, to cut the pant, rather than for it to rip from a spinning rivet head. They all came out clean. So, all I have are some shiny rivet heads showing on my painted side skins, near the front. A little touch up paint with fix that later. I guess that shows my faith in the folks at Van's. Somebody there decided that this was a good idea, so I went with it. I'll sleep better anyway.

Tom
 
Ordered

Mine last week - I have often wondered why Van's doesn't make this and others like it available thru their regular parts order - ie 'on line'? So, I guess that I got the answer when I called and the whole transaction took only about 30 seconds with a real person! That lady is efficient!!!:cool:
 
Jersey and Dave12,

I see you doubt the mod is only for noise, but wouldn't it be a service bulletin per the LSA regs if it was meant to be more than optional? Do you have a reason behind your doubts?

This is not a rhetorical question because I don't intend doing it based on noise.

Rich
 
Vibration and fatigue

I hope that all of us can agree that noise can be a result of vibration. Remember the vibrating forks in high school science class.

Although not all vibration is destructive...it depends on the harmonic characteristics, amplitude and frequency of the item that is vibrating. I remember a photo of a crack, on this forum, near the area that is now receiving the additional stiffening.

Mitigating vibration is good. I would install the kit. Go to:

http://en.wikipedia.org/wiki/Vibration_fatigue
 
Jersey,

Look at your N/S curves. There is a thing called the endurance limit where cumulative usage factor is zero.

Rich
 
S/N Curves

The N/S curves mentioned is more commonly known as the S/N Curves. The S being the amplitude of deflection and the N being the number of cycles. Without measuring the amplitude (S) of each component of the structure it would be impossible to predict that the fatigue life of a structure is infinite (ELC of 0). The endurance limit curve predicts Cf (Cycles to Failure) and plots exponentially with amplitude. The amplitude can be driven by a number of souces including propellar and engine imbalance and or the composite of the two (resonation).

Jersey
 
I've started working on the stiffener kit. It is so official, that it even received a shiny new section number - 54.
It appears that Van's changed the dimpling on the firewall in the area where one of the stiffeners is installed as the retrofit uses a spacer to clear the existing dimples but the instruction tell you not to install it if the dimples are missing.
The retrofit on the FW is quite easy but requires removal of the lower cowl and possibly removal of the gascolator bowl (I will see if I can avoid that).
Lots of pictures in my blog.
I should get to the side skin stiffeners by Sunday, at the latest.
 
Jersey,

You seem well versed in fatigue theory, so why would you assume the oil canning stress cycle would be severe enough to initiate a crack without evidence? My conclusion is that Vans has the data and if they thought it was a structural issue they would issue an SB. If I was still building I'd probably put it in, but I don't see any compelling reason to screw up my paint again (the MLG mod had to be done).

Rich
 
New Design

Howdy Rich,

Please forgive my paranoia....this is a new design with relatively few hours. Not questioning your premise. I hope your spot on. Time will tell.

Regards,

Gary
 
Jersey,

If this does come back as a structural issue I would think Vans would have a lot of egg on its face for not making this an SB when it was identified for redesign. So far they've done a good job on product support, so I trust their judgement absent evidence to the contrary.

Most of my experience in the fatigue arena has been with thermal cycling in power plants as opposed to vibration induced fatigue. We usually didn't worry about it unless we could see movement. There were usually other issues at stake like bearing wear that trumped vibration induced fatigue. The exceptions to that were few but memorable!

Rich
 
Dave12 said:
The Gascolator Bowl has to be removed, that's all.
Click to expand...
Yep, Dave is right. A closer look revealed that there is no clean way to get to that rivet without removing the bowl or at least the plug. As you will need a bit more room for clecoing, removing the bowl is a must.
 
MacPara said:
Yep, Dave is right. A closer look revealed that there is no clean way to get to that rivet without removing the bowl or at least the plug. As you will need a bit more room for clecoing, removing the bowl is a must.
Click to expand...

Well then, that makes the decision easy for me! Not gonna happen until either it becomes an SB, or next year's condition inspection, whichever comes first. ;)
 
Gascolator Bowl

So, what's the big deal about taking off the bowl. With the fuel shut off, and 4 screws, you're there! Am I missing something here. I had mine off in about two minute...........Tom
 
Sorry!

Sorry, it does take longer to put it back on and to safety it. Not major, but a bit more time consuming.

When I first installed the gascolator, I noted the difficulty in getting at the left rear screw for the bowl. I understand the need to remove the bowl and to clean it out occasionally, so I did a no-no. I drilled a small 3/16" hole in the nose gear plate, right under that screw. Now, I can get straight on it and feel much better about doing the job. It still need safetied though.
 
My nose gear came with a hole already drilled in the plate, however it was on the wrong side so I did as you, I just drilled a matching hole on the other side.
 
Some of the early shipped finish kits did not have the screw access hole (or it was on the incorrect side).

For quite a while it has been included in the part, but there was also a plans revision that provided dimensions for where to add the hole if it was not already there.
 
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