149 replies to this topic

[Wallowa]

Ted, thank you.  I too believe this problem will continue on some campers until the builder changes how the roof is constructed.  What I don’t understand is why the “fix” is left to the owners, or why the owners are willing to accept this.

 

Concur...but honestly if FWC does not, will not step up, how would I or any FWC owner induce them to:

 

#1 Acknowledge there is a problem with the design, material or installation of the single piece top sheets and;

 

#2 Remedy the oil canning issue through repair or replacement of the top sheet once the exact nature of the deficiency is determine.

 

Most recently I have closely examined  the top sheet on my Hawk with low angle back lighting and the waves or slack is prevalent in all areas of the sheet.  Also I can tension that slack by putting pressure on adjacent area on either side of a roof stringer/strut; however to stop sections from flexing up and down direct pressure is required over the distorted areas.

 

Basically I believe any material placed over the slacked areas will attenuate the up and down oscillation of the top sheet that produces the oil canning racket.  This material must have sufficient mass to eliminate or slow down the flexing in these slack areas enough to stop the sound produced by the up and down flexing of the tops sheet aluminum.  I have experimented with different materials in lieu of the aluminum bars I have purchased and wood strips will also dampen the movement and noise.

 

My 3 " wide and .313 " thick aluminum flat bars could have been .250" thick and been adequate; BUT the reality is that the entire top sheet has slack and I certainly can't cover all the waves in the tops sheet to lessen or stop the noise.

 

Lastly....Adding thicker insulating foam between the top frame member MIGHT lessen or stop the distorted areas from flexing up and down...issues with that approach would be how thick does the foam need to be to work in all areas, how can that foam be inserted/attached and would the thicker top insulation and reduced inside headliner height inside allow the end boards to function and still have sufficient space to sleep in overhang area.

 

Still experimenting with external means to stop the flexing of distorted wavey top sheet....will post if I have a break through...don't hold your breath!

 

Phil

 

Ps...STAN...I know you are not the person who has the clout to prompt FWC to get off the dime and take this issue on...but please bring it to the attention of the "Powers-That-Be"...ignoring this defect will only hurt sales and confidence in FWC.

Edited by Wallowa, 08 July 2023 - 08:05 PM.

[Wallowa]

This has been an interesting thread just to learn so much from the engineers and see the brainstorming for solutions evolve. Vic asked if we have confirmed that the roof needs to be detached for the oil canning to occur. I would say the answer is no. In my case and that of Wandering Sagebrush we had this problem from the start with new campers. I also know my roof was attached as FWC did take my roof apart and Stan stated they had to chisel the aluminum from the frame. And these being new campers also would indicate that the aluminum does not have to be stretched from snow load, vibration, or anything else. And since it was still attached to the rafters, I don't see how adding screws would help.

It appears a solution or two may be at hand, whether adding aluminum pieces as Phil is doing or arcing the roof by pushing it up from the inside. Hopefully those with this problem will soon be able to sleep well in their campers. Why only some campers are experiencing this is a mystery. But, IMO, the smooth aluminum will still be a problem for new campers yet to be built until FWC replaces it with a different product, such as the diamond stamped door a few pages back.

 

 

Ted you said "FWC did take my roof apart " was that to address an oil canning problem?  What did FWC do when they removed the top sheet? Whatever the issue did they fix it?

 

Thanks...Phil

[Vic Harder]

Ted said that they chisled the roof sheet off of the roof rafters, so the VHB was still working AND it was still oil canning.  Bummer.  That means screwing it down won't fix it.

 

It had been suggested earlier that using sound dampening, like Dynamat or similar would help.  Maybe.  You could try a bit of that in some areas and test.  If that works, I'd be tempted to remove the headliner (BIG job) and insulation and add that from underneath before reassembling.  It would add a LOT of weight to the roof though.

[Wallowa]

Ted said that they chisled the roof sheet off of the roof rafters, so the VHB was still working AND it was still oil canning.  Bummer.  That means screwing it down won't fix it.

 

It had been suggested earlier that using sound dampening, like Dynamat or similar would help.  Maybe.  You could try a bit of that in some areas and test.  If that works, I'd be tempted to remove the headliner (BIG job) and insulation and add that from underneath before reassembling.  It would add a LOT of weight to the roof though.

 

 

Respectfully I do not believe any amount of sound dampening / sound proofing material would stop the loud oil canning booming racket from being heard ....I believe you must stop the movement of the distorted and slack areas in the top sheet to eliminate the oil canning noise..thicker foam board that FWC used under the top sheet that pushes up against the under side of the top sheet MIGHT stop or lessen the up and down vertical movement and oil canning noise...thicker rigid foam would not add a significant amount of weight... 

 

But hey, I could be wrong

Edited by Wallowa, 08 July 2023 - 11:39 PM.

[JaSAn]

Respectfully I do not believe any amount of sound dampening / sound proofing material would stop the loud oil canning booming racket from being heard ....I believe you must stop the movement of the distorted and slack areas in the top sheet to eliminate the oil canning noise..

 

 

There are four ways to reduce/change vibrations (oil canning is a simple vibration).

Add mass: lowers natural frequency and lowers amplitude (takes more energy to move)

Add stiffness: raises natural frequency and lowers amplitude (same reason)

Add dampening: converts energy to heat (vehicle shock absorbers)

Add deadening: vibration looses energy navigating through layers (blankets and soft foams)

 

Mass is the best for low frequencies (1 to 250 hz).

Stiffness works well at low and mid range frequencies (250 to 2000 hz).

Damping materials work best in the mid range.  

Deadening works best at high frequencies and very poorly at low and mid range frequencies (needs too much thickness to be practical).

 

I am surprised that no one has contacted acoustic engineers that do this.  This problem should have been solved.  I've been retired for 12 years and have forgotten a lot.

[ckent323]

JSan,

 

Good comments.

As I wrote in an earlier comment,  I think CLD (Constrained Layer Damper) tiles may help.  I used them to stop the noises from the roof and the doors skins of my truck.  They are peel and stick.  They are cheap enough to try and are easily cut to fit.  They do not cover an entire surface area they are spread out to cover about 25% or the area.

 

Source:

https://resonixsound...ound-deadening/
 

I recommend contacting the folks at Resonix and explaining the problem.  I suspect they can help.

 

 

I hope this is helpful info,

 

 

 

Craig

Edited by ckent323, 09 July 2023 - 07:09 AM.

[kmcintyre]

After reading many of the comments (but not all) here's my take, views, options, concerns, etc......

 

If the original roof design (with screws) didn't have this issue AND the new model has the same roof structure, then the problem is the adhesive.

 

If the original roof design (with screws) didn't have this issue AND the roof structure is different, it's not clear to me what the issue is but it's either the engineering design and/or adhesive.

 

If the original roof design HAD this issue, I never heard of it and mine didn't have the issue.

 

So, in my opinion, FWC could address this in a few ways:

a) find a "donor" FWC that has the issue and take the roof off and find out if the adhesive failed AND/OR the roof design needs to change

somehow resolve the issue (an example would be like what VW did with their diesel enigine issue albeit that was a completely different case)

  1) compensate owners

  2) do a massive recall (not sure how they'd do that) and replace the adhesive

  3) purchase units back

 

The question I think (for any lawyers out there) is what FWC's liability is and if they are subject to a class action suit.  I haven't seen much discussion/input from FWC except early on and have to wonder if they are looking into the issue, ignorning the issue, don't want to comment due to potential lawsuits or some other reason. 

 

I'm not advocating a lawsuit but I've seen those come up for many of these types of issues.

Edited by kmcintyre, 09 July 2023 - 11:43 AM.

[Wallowa]

There are four ways to reduce/change vibrations (oil canning is a simple vibration).

Add mass: lowers natural frequency and lowers amplitude (takes more energy to move)

Add stiffness: raises natural frequency and lowers amplitude (same reason)

Add dampening: converts energy to heat (vehicle shock absorbers)

Add deadening: vibration looses energy navigating through layers (blankets and soft foams)

 

Mass is the best for low frequencies (1 to 250 hz).

Stiffness works well at low and mid range frequencies (250 to 2000 hz).

Damping materials work best in the mid range.  

Deadening works best at high frequencies and very poorly at low and mid range frequencies (needs too much thickness to be practical).

 

I am surprised that no one has contacted acoustic engineers that do this.  This problem should have been solved.  I've been retired for 12 years and have forgotten a lot.

 

Obviously...I am not an acoustic engineer...but I have arrived at the same conclusions as I have stated in my posts....I am not addressing a re-design of the top sheet; that is not within my purview or ability.  However, of the four potential remedies listed above only adding mass/stiffness to the distorted areas [slack areas that vibrate/flex up and down to produce the oil canning boom] is a viable option for me.  I am working with aluminum or other materials in direct contact with the top of the sheet that will have sufficient mass and stiffness to slow down or stop the flexing of the top sheet enough to stop the booming.

 

"Stiffness' would require a new top sheet of difference design and or thickness.

 

"Dampening" material must be in contact with the slack areas and I only have access to the top of the top sheet.  CLD as I read it must be inside and not exposed; if it would work, it would need to be adhered to the underside of the top sheet.

 

"Deadening" is a non-starter for frequency range and necessary thickness to abate the sound.

 

Not beating a dead horse, but engineering solutions, actually any solution, must be real world tested to verify effectiveness.  I work in my shop and not a lab.  It can start with theoretical but must end with empirical proof of the hypothesis.   In short the proof of the pudding is in the eating.

 

Yes...FWC is in my opinion on the hook for the distorted and oil canning top sheets; regardless of the cause.  Has anyone directly contacted FWC about this issue or has FWC examined their top sheet to determine why the sheet has distorted?  FWC is the party who should contact an acoustical engineer to address this problem.

 

Phil

Edited by Wallowa, 09 July 2023 - 01:23 PM.

[Rocklobster]

Class Action anybody?

[kmcintyre]

Class Action anybody?

 

Realistically, if people want FWC to resolve this, that's probably the only recourse.  Whether or not people want to litigate is another question.  If there was an easy answer, I do think FWC would have addressed it.  It's not an easy fix as each unit would have to have the roof removed (assuming the fix isn't to put screws in the roof) and each unit would have to be taken to a dealer (if not the factory).  The factory probably doesn't have the resources to take in all these units and wonder if the cost to repair would cause them to go into Chapter 11 bankruptcy.

 

Personally, I'm overall happy with my 2 FWC's I've owned and they've been great to deal with.  I have the issue like others and I guess it's about how important it is to each individual and distress it causes you as to whether or not you want to persue a fix.

Edited by kmcintyre, 14 August 2023 - 02:17 PM.