Front end shake as if driving over a washboard/rumble strip

[Concourse]

Mine has no noise..........

[Concourse]

Which is why I was asking. A previous owner had this mod done and I got the RV this way so other than rebuilding the Fantastic Fan (gearbox) plus wondering why there was no locking arm (replaced) I've not experienced wind noise. There was some noise from the back side before I got a working dome lid lock but that's gone. I figured that since someone made the effort to fabricate the aluminum wind deflector and mounting frame it was warranted.

[Blue~Go]

Aha! And it worked! That's good to know. Is it aluminum? Formed and tucked under the flange of the vent? I may have to just copy that - great to know it works.

And yep, without it it sounds just like you have an open hole in the roof, with all the wind noise you can imagine from that. Yet when I wrapped the dome/curb seam with THREE rounds of duct tape (to see if there was an air leak).... no change whatsoever.

I don't know why, but I didn't even think of just putting it under the flange. I want to re-bed the vent anyway.

[Concourse]

Now I get it. So the aerodynamic front of these Chinooks is great for mpg and such but the FF gets the wind. The mod is a simple aluminum deflector and sits in front of the dome and it's flange/mount. There is a bracket that uses a couple of the dome to coach mounting screws but they are on top of the flange.

[Blue~Go]

Thanks for the detail - I see now how it is attached (I copied your photo into my viewer and zoomed in). This gives me some good ideas. Oh I can't wait for that particular wind noise to be GONE.

And yes, that is apparently the issue. They said there are some specific models of Winnebago, etc (i.e higher volume RV's that they are more familiar with) that tended to have the problem, due to vent placement near the front, shape of front/roof, etc.

[1998chinook]

Thanks Concourse, that gives me some hope that I'll be able to eliminate that wind noise.

[Concourse]

No problem. Always trying to share and help. The construction looks to be ........Tthe aluminum deflector is just a simple angle bend plus the top corners have been folder probably so nobody gets hurt. The frame looks to be steel as it's oxidized. It is made from three pieces of some sort of steel flat stock. The two short pieces that use the FF front corner screws to attach to the coach are welded to the long bar that runs parallel to the front of the FF. The deflector is slid underneath the steel frame and stops when it hits the FF surround. I can't tell how the deflector is attached to the frame and being that that are different metals I doubt they are welded together. There is some sealant squirting out from between the frame and deflector so maybe a combination of down pressure of the frame, tight tolerance, and a bonding sealant?

[caconcourse]

After reading about the Fantastic Fan Noise and shroud "solution", here is a possible cheap fix.

I happened to come across a bunch of "MaxxAir" fan vent covers in our local dumpster (what are the odds?). I took some home and modified one by cutting off all of the upper layers, which left a nice air deflector with mounting holes, sized to exactly enclose the fantastic fan. You can buy these vent covers anywhere for about $25. I can't report on the effectiveness yet, since we haven't gone anywhere yet, but it looks better and hopefully will deflect the offending wind.


Here are some pictures of the vent cover before modification, and the installed shroud:

[Blue~Go]

Ooh, please do report back! I was thinking of fabbing something from fiberglass, but if a ready-made (or "readily made") off the shelf item exists... why not.

[1998chinook]

Thanks for the tip.

Have you thought about cutting the back half or back third off to allow water to escape? Any concerns about water getting trapped?