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Posted by: Randal Feb 27 2010, 12:28 PM

I just bought an air deflector that is 64" by 34" and will be bolting it to my trailer in front of the tire rack. You've seen these deflectors on big diesel trucks, kind of looks like a big snow board.

I might have to move the tire rack back 6 inches to get the rake I want, but here is my question?

Is it better to mount it low or high?

I can mount it on the trailer A frame, directly behind the triangle aluminum box, but I'd have to move the tire rack back at least 6".

I can mount it next to the back lip (cover) of the aluminum box but will still have to move the tire rack.

In any event, where will I get the best air flow to help mileage?

Posted by: Randal Feb 27 2010, 02:59 PM

Here is a picture of the (dirty) deflector. This is the angle I think will work, but I'll need to move the tire rack back 6".

Right height?

Posted by: Randal Feb 27 2010, 03:00 PM

One more picture:

Posted by: koozy Feb 27 2010, 04:31 PM

I think it will work just fine. Is it fiberglass or aluminum?

Posted by: Randal Feb 27 2010, 04:37 PM

Fiberglass. It will look good when repainted. Structurally perfect

One can only guess how many miles it has seen.

Posted by: URY914 Feb 27 2010, 04:43 PM

Looks cool and should work well.

Posted by: URY914 Feb 27 2010, 04:46 PM

Higher would be better as it will smooth out the air over the top of the car.

Posted by: Randal Feb 28 2010, 12:08 PM

I'll mount it high as you suggested and also leaning back as in the picture. Think moving the tire rack back 6 inches would be just about right. Of course I'd still have to figure out where to put the tank. Maybe weld the rings to the front cross bar of the trailer. Yea, that might work, but it would be hell to get the (heavy and awkward) tank into the rings without any real flat surfaces except the top 2" of the cross bar.

Or I could get rid of the trailer box, which would be the easiest of all solutions.

Or i could mount the deflector right where it is shown in the picture, then use removable pins on the bottom so I can just lift it out of the way when I need to get into the box.

Posted by: URY914 Feb 28 2010, 01:22 PM

Maybe you could somehow hinge the deflector to flip it up for access to the box. Removing it each time doesn't sound like much work now but it will soon become a PITA when you need to get it the box for one little thing.

Posted by: Randal Feb 28 2010, 01:42 PM

I think that idea might work, the question being how high it will lift before hitting the tires.

The cool thing about the deflector is the attachment points. That together with the U channel (previously attached to the top of the truck) which is drilled so you have any combination of angles to work with.

Here is the back side of the deflector.

Posted by: koozy Feb 28 2010, 02:28 PM

Ah, I think I got it... Make it so the thing is hinged at the top. It goes over the edge of the box when in driving position and when you need something in the box, the bottom drops so the deflector is vertical.

Posted by: koozy Feb 28 2010, 02:29 PM

Then it doesn't hinder tire removal either

Posted by: Randal Feb 28 2010, 03:07 PM

Given the rake I want, i.e., the picture with the AD over the box, not behind it, I think the AD will lift up when the pin is removed. My only question is whether it will lift enough to open and get stuff out of the aluminum box.

It will be easy to figure it out when I can get back to the trailer again.

Here is a picture. Imagine all the red bars as being behind the deflector.

Here's to good mileage.

Posted by: URY914 Feb 28 2010, 04:37 PM

Happy motoring!

Posted by: Randal Mar 1 2010, 02:16 PM

I went back and looked at the air deflector again today. Installation is going to be easy.

I just have to bolt the U channel to the front uprights on the tire rack.

Then move the four attachment points on the air deflector out about two inches

The top attachment points will then bolt right into the top hole of the U channel, the bottom will be attached using existing L channel.

The bottom attachment will be easily accessible, so with a 1/2 pin and keeper, that can be pulled out, the air deflector will go up about 15 inches allowing the lid on the aluminum box to open.

Posted by: URY914 Mar 1 2010, 02:32 PM

Don't you love it when a plan comes together.

Posted by: Randal Mar 1 2010, 02:36 PM

Yea. Can't wait to test the mileage.

Posted by: grantsfo Mar 1 2010, 11:43 PM

My trailering MPG went up when I put shell on my truck.

Posted by: camaroz1985 Mar 2 2010, 07:42 AM

Also will help keep those little stones and stuff from being kicked up onto your car, though I guess you had the tires there before.

Posted by: ChrisNPDrider Mar 2 2010, 10:53 AM

Does this mean we will see Randal and 222 at a GGR AX this year?

Posted by: grantsfo Mar 2 2010, 01:45 PM

Wow that would be cool! Havent seen 222 forever!

Posted by: RobW Mar 2 2010, 02:10 PM

Posted by: Randal Mar 7 2010, 03:43 PM

Well I have all the mechanicals worked out and test fitted the air deflector on the trailer. It's going to be cool looking and my aluminum box is accessible by just pulling two pins.

Now I'm fixing the body work stuff and will shortly paint it.

I had forgotten how resin smelled.

Can't decide which color to paint the deflector, i.e, white, silver or dark blue (like the letters 222).

Finished pictures sometime next week.

Posted by: Randal Mar 10 2010, 03:39 PM

Uggg...

I sanded then primed my air deflector, after fixing the big holes I had to fill with fiberglass and resin and low and behold, hundred of little holes from miles on the road, a-top a semi.

I've just covered all the holes with puddy and will sand with 80 grit, then primer again to see if I missed any.

Wish I had some heavy (fill type) primer in the garage.

Posted by: URY914 Mar 10 2010, 05:20 PM

Perfection always takes time......

Posted by: Randal Mar 26 2010, 12:12 PM

Progress:

Posted by: Randal Mar 26 2010, 12:14 PM

And another:

Posted by: Randal Mar 26 2010, 12:17 PM

What I learned.

I used Rustoleum from the local hardware store. A proper automotive paint would have been better.

To get the paint to flow out of the gun I had to thin it about 25%, which made it run very easily.

Between coats I let it dry for a day, then wet sanded out the runs.

I still have one small run, but it isn't bad. One more cycle and it'll good to go.

Posted by: grantsfo Mar 26 2010, 01:25 PM

Looking good Randal. I looking at building something similar to this.

Posted by: URY914 Mar 26 2010, 02:20 PM

Looks good. BTW, don't call the "runs" call them "sags". The pro do and it makes you sound like you know what you're talking about, even....

Posted by: Randal Mar 26 2010, 09:20 PM

Actually I didn't "sag" as many as I thought. The one sag that did show up was a bad blocking job by me .

One more cycle and I think it'll look presentable.

Next I need to re-paint the trailer.

Posted by: Randal Apr 1 2010, 03:03 PM

Finally got the final coats on, without any sags. I wasn't going to paint them today as it's cold for California and we had lots of clouds. But the clouds parted, my part got warm and I went ahead and shot it.

Didn't come out bad and I was using a paint (Rustoleum) that runs easily, especially when thinned to shoot out of a gun.

Learned a lot during this process.

Today:



Finished at last:

Posted by: URY914 Apr 1 2010, 04:12 PM

Very nice!

Posted by: Phoenix 914-6GT Apr 1 2010, 04:52 PM

Nice work Randal.

Posted by: Randal Apr 8 2010, 11:21 AM

Thanks.

All done now.

Posted by: Randal Apr 8 2010, 11:23 AM

And another:

Posted by: Randal Apr 8 2010, 11:24 AM

Last one:

Posted by: 6freak Apr 8 2010, 12:16 PM

Nice work ..but Ill bet you just created more drag then you started with ...JMO...you where going for better mileage correct!

Posted by: URY914 Apr 8 2010, 02:58 PM

You need three lights aross the top like the big rigs have.

Looks great!

Posted by: Randal Apr 8 2010, 04:07 PM

That could very well be, but we'll find out when I tow the car next. Yes, mileage was the objective.

Posted by: Randal Apr 8 2010, 04:08 PM

Now lights would be cool!

Posted by: Phoenix 914-6GT Apr 8 2010, 04:55 PM

Looks awesome I would bet it will help protect whatever you are looking to tow as well.

Posted by: Randal Apr 8 2010, 09:28 PM

Paul, maybe someone else as well, said it would better mounted higher to get air flow over the car, so that is what I did.

It's adjustable, so I just have to try different settings.

Posted by: Randal Apr 9 2010, 07:18 AM

Should do a good job of that, given the height.

Thinking about what you said brought up an interesting idea. What makes the white fog like they use in wind tunnels to view air flow?

It would be pretty easy to video it at speed as long as you could figure out something allowing you to visualize the air flow.

Posted by: Phoenix 914-6GT Apr 9 2010, 04:02 PM

I think they actually use a machine that is similar to the party fog machines. That would be a cool test to conduct

Posted by: DanT Apr 9 2010, 10:36 PM

Randal, your tires on your tire rack give you more drag than the car does...IMHO
Once you move the air over the tires it should continue right over the car.
Other than keeping rocks and debris off the front of your car, I doubt you will see much difference in MPGs...of your truck...
and remember the air coming off the back of your truck with the tailgate up actually forms a vacuum in that area.

Posted by: Randal Apr 10 2010, 08:48 AM

I wonder how much the vacuum is reduced given that I have a complete cover over the bed of my truck?

Posted by: DanT Apr 10 2010, 09:21 AM

the cover just keeps the wind out of the box. You still have two areas that create vacuum. the back of the actual cab, and then the back of the box at the tail gate.
your car sits so low and the tire rack is even pretty low...so I am not sure there will be a huge difference, but you will definitely keep some debris off the front of 222.
I am probably completely wrong

Posted by: URY914 Apr 10 2010, 04:48 PM

It gives the rig a clean look. That's what counts.

Posted by: blabla914 Jun 17 2010, 11:10 AM

Thinking about what you said brought up an interesting idea. What makes the white fog like they use in wind tunnels to view air flow?


Have somebody video your rig driving in a light rain or just a wet road. The spray will show you a lot. Cheap and easy to do, but difficult to get the timing down. You have to have your rig all set to go and somebody lined up to video when it's raining. Naturally it can't be raining too hard as the rain will obscure what the spray is doing.

I see a consistent 1-2 mpg gain on my crew cab gas chevy using a tonneau cover when I'm not pulling a trailer. I'm not sure it has the same effect dragging the trailer. I just haven't done enough driving with/without tonneau and the trailer. That said I have to agree, even your tires aren't that high relative to the top of the tail gate

In the end, I have to agree....Most of the benefit will be keeping the crud off your car.

Kelly