Wind Deflector

[MikeJinCO]

I'm going to put a wind deflector on the truck overhang of our Host Mammoth. Does anyone know if it is a Azdel of luan panel? Do I need to predrill the fiberglass oversize to prevent the fiberglass panel cracking? I'm using panels of fiberglass about 1/8" thick that I laid up as not a lot of plastic sheeting is available around here.

[notsobigjoe]

All the way to the bottom of the the first link.
https://www.truckcampermagazine.com/off-road/extreme-rigs/alaskan-dream-machine/
I wonder if this would tuck in under the cab over so you wouldn't have to drill anything into your camper? Click on quick view.
https://www.icondirect.com/categories/RV-Towing-Products/Wind-Deflectors/AeroShield/
Sleepy's old rig and others. Sleepy had his camper overhauled a couple of years back and that thread is on LOA. You'll have to be a member to see it.
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/25642689/print/true.cfm
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/17575645/srt/pa/pging/1/page/1

[HMS_Beagle]

notsobigjoe wrote:
https://www.truckcampermagazine.com/camper-mods/projects/4-camper-air-dams-and-wind-deflectors/

Thanks for pointing out that link. The guy who used a molded valence was brilliant.

[HMS_Beagle]

To fasten it, why not some VHB tape? Or 5200 or Sikaflex? Those would removable (with some effort...) and would not create leaks. Should be plenty strong enough, but does depend on the skin being solid or fastened to something solid. That is how I intend to mount one if I do anything.

JimK-NY wrote:
I would expect Zero improvement. The gap between the truck and camper seems to be a total dead zone. I have never seen bugs, dirt or water enter that area regardless of speed or conditions.

I have little or no significant wind noise due to my camper. If you have wind noise, I would look elsewhere. Start with protrusions and irregular areas. I would look at the gutters, running lights, vents, and similar.

On your camper. Not mine. I have quite a harvest of bugs mainly on the outside edges of the camper but extending in and even all the way across up high (over the cab). There is also a nice pattern of bugs under the overhang somewhat defining the shape of the cab. There is definitely more wind noise with the camper on that with it off. Every situation is going to be different. I have a supercab, not a crew cab truck, so the camper overhang extends some distance ahead of the windshield. The camper overhang sits pretty low, maybe only 6" above the cab roof. The Bigfoot has no sharp corners or irregular protrusions. The airflow around the truck and camper has got to be pretty complex, not easy to visualize without a wind tunnel. I've thought about tufting it and photographing the flow, and might do that prior to and mods.

pianotuna wrote:


Consider Air Tabs?

I've looked as them, and could see the possibility of filling in the low pressure behind the camper. Less sure about the area underneath the overhang. Back when Sleepy was describing his, someone did pop up who had tried the on the front of his camper - put them underneath the overhang if I remember - and said they reduced the wind noise. If they were cheap I might try that, actually it would only cost about $70 so might be worth a try.

[pianotuna]

I have air tabs. They do reduce drag from big trucks. They don't appear to improve mileage--except when I have a tail wind--then they increase mileage more than when I did not have them.

My RV was fairly stable to begin with.

I placed them on the trailing edge of the air conditioner cover, and at the rear of the vehicle.

[Grit_dog]

Evidently different truck/tc combos have different airflow patterns.
While I agree with jimk that this is likely of no practical benefit, our campers were plastered with bugs directly behind the cab.

[notsobigjoe]

https://www.truckcampermagazine.com/camper-mods/projects/4-camper-air-dams-and-wind-deflectors/

[StirCrazy]

pianotuna wrote:

HMS Beagle wrote:
I'd not be expecting much difference in mileage, but would be looking for a reduction in wind noise in the cab, and maybe a reduction in bug count.

None of the videos by Blair seem address the truck cab/camper gap, other deflector on other type RVs.

Consider Air Tabs?

Have you used them Don, I have been wondering about them for both the back of my camper and the 5th wheel ro get rid of the drag zone behind the unit.

Steve

[pianotuna]

HMS Beagle wrote:
I'd not be expecting much difference in mileage, but would be looking for a reduction in wind noise in the cab, and maybe a reduction in bug count.

None of the videos by Blair seem address the truck cab/camper gap, other deflector on other type RVs.

Consider Air Tabs?

[MikeJinCO]

And the winner is HMS Beagle. When you have a fiberglass shell with a wood backing and you want to put a screw into the backing an oversize hole should be drilled thru the fiber glass only because the higher temperature expansion rate of the steel than the fiberglass will cause the fiberglass to split. So the question is wll the same thing occur with these composite skins?

Many years ago we had a member named Sleepy who figured out how to do these wind deflectors out of plastic gutter covers. They worked quite well to prevent the air steam from hitting and flexing the front of the camper shell quieting down the ride in the cab and also deflecting the insects that get almost embedded to the camper wall. The holes in the gutter cover also prevent a low pressure area forming behind the wall which can be an issue.

When driving a barn door down the road, the only thing that I know of that helps fuel mileage is keeping your foot out of the turbo. The closest "big" town is 12 miles away and with a road that appears almost flat is 1300 feet lower and when the road west of the driveway heads up 3000ft to Monarch Pass. Staying out of the turbo is impossible. On the other hand when I roll 4000 ft down hill toward Canon City my fuel range drops by about 6-8 miles in 60 miles.

The design is really quite simple. Following Sleepy's concept my front panel will be 16" wide fastened in the center to the front bottom seam of the overhanging bed then taper back about 18-20 inches to the edge fastened up to the underside of the camper. The panels are pop riveted to some 1x1 LW aluminun angle then fastened to the camper with VRB tape and #8 screws. I'll leave the panels about 2" clearance from the cab of the truck to prevent any interference problem due to either movement of the camper or flexing of the truck.

[JimK-NY]

I would expect Zero improvement. The gap between the truck and camper seems to be a total dead zone. I have never seen bugs, dirt or water enter that area regardless of speed or conditions.

I have little or no significant wind noise due to my camper. If you have wind noise, I would look elsewhere. Start with protrusions and irregular areas. I would look at the gutters, running lights, vents, and similar.

[HMS_Beagle]

I'd not be expecting much difference in mileage, but would be looking for a reduction in wind noise in the cab, and maybe a reduction in bug count.

None of the videos by Blair seem address the truck cab/camper gap, other deflector on other type RVs.

[bgum]

Azdel should have a sticker announcing same near your door.

[JimK-NY]

Before you bother, you might want to check some studies to see if it is likely to make even a slight improvement in mileage. The only results I have seen were on YouTube and the deflector made no detectable improvement in mileage. (The YouTube video was from Marion Blair.)

[TxGearhead]

Assuming you are looking for better fuel mileage?
I don't know of a way to calculate the stress you will put on the camper.
Just my opinion but the small gain would not be worth the possibility of doing expensive damage to the camper.
edit add...I'm not understanding the oversized predrilled holes. Will you be pulling off the interior wall covering to put washers & nuts on the interior sides of the bolts? If so, making the holes oversized would reduce the holding power of the bolts. Or, are you thinking of just screws with no nuts?
If I was going to do something, I would think about a spoiler mounted on the rear of the roof to reduce the negative pressure behind the camper. Maybe bolted to a luggage rack, not screwed in the roof.

[HMS_Beagle]

Don't know the answer but am interested in seeing a picture of the result, as well and any impressions on what it changed. Been thinking of this myself.