Big project-F250 pulling 20x8.5 enclosed trailer

[5.0 Junkie]

Holy Sh!t. That is sweet. Any mileage testing? More pics?

Originally Posted by botsapper

My aero mods on the trailer package. Must first address the truck fairing. There is a retractable hinged top to serve as a bow fairing. Many truck cab designs use this retracting fairing combination. To seal off as much gap between the trailer & fairing, there is another cone fairing/storage on the top front on the trailer. An adaptation of Don-Bur teardrop profile is added on top of the flat trailer top. And at the end there are hinged foldaway panels that extend the trailer for your on road long-tail configuration. Front & rear spats for the bogeys, and wheel covers compliment the whole package.

Take your pick or add all of the aero treatments.

[Christ]

To attach the rear pieces, you can just attach them to the door and break the angle out a little more. It won't be as much of a help, but the area that gets lost in there is minimal.

That will make it so you don't have to get plexi or worry about blocking the lights, but you should put reflective tape on the trailing edges of your additions to draw attention to their depth. The upper one can be attached like an awning to the top of the trailer, and won't interfere with the door opening downward. The parts on either side that attach to the doors can be hinged to fold into the face of the door when it needs to be opened, and can have bolt locks on them to lock into the upper part when the door is closed and they're open.

A single screw-on plate across both tires on both sides of sheet metal or even coroplast will work fine for the wheel covers, and is easily removable in case of tire service.

The trailer sits kind of high, I think. If it doesn't have suspension, you can disregard this, but if it has springs, you could lower it's height and put air-helpers in there for when you need more clearance. The lower the trailer is, the less topper you need, and less frontal area you have to deal with.

If it doesn't have suspension, you can just add some semi-flexible skirts (conveyor belt material works great) to the length of the sides to keep excess air from getting under there.

[bondo]

Originally Posted by botsapper

My aero mods on the trailer package. Must first address the truck fairing. There is a retractable hinged top to serve as a bow fairing. Many truck cab designs use this retracting fairing combination. To seal off as much gap between the trailer & fairing, there is another cone fairing/storage on the top front on the trailer. An adaptation of Don-Bur teardrop profile is added on top of the flat trailer top. And at the end there are hinged foldaway panels that extend the trailer for your on road long-tail configuration. Front & rear spats for the bogeys, and wheel covers compliment the whole package.

Take your pick or add all of the aero treatments.

(Conceptual ideas only)

If you ever decide to build it, if I can be of any help, let me know. You may want to look at getting a patent and then approach some trailer manufacturers.

Again, great concept!

Bondo

[MetroMPG]

HOLY COW! Botsapper strikes again with a killer photochop. Thanks!

Originally Posted by Christ

Looks like they found that rear side panel accounts for the largest reduction in drag... I wonder how that scales down to our sizes?

Having seen the pics of 5.0 Junkie's trailer, he's already very low to the ground. Probably not much to be gained, percentage-wise, by adding skirts. The main benefit on tractor trailers is they keep airflow away from the rear wheel truck. Not an issue for Junkie.

Originally Posted by 5.0 Junkie

I was trying to think of a way to put the "wings" on the back of the trailer.

If you're referring to the angled panels on the sides & top of the trailer at the very rear, let's call them a "partial boattail" instead of "wings" - terminology's important!

On the wheels, will just a flat skirt on them suffice, or do I need some moon caps too?

I think a flat panel would be the largest gain. Moonies wouldn't help much if covered. You could also add some material (carved foam) to taper/blend the fender & skirt area backward into the trailer side.

I'm likely going to break down and buy one of the extended height camper shells to help there.

I think that shell is going to help a lot, particularly if you can put a deflector on top, or add a "bubble" to the upper forward face of the trailer (as in Botsappers picture) if you don't.

I noticed the corners from the face to the top & sides are hard. If they were radiused, you'd have cleaner flow along the tops and sides as well.

[MetroMPG]

Originally Posted by 5.0 Junkie

Holy Sh!t. That is sweet. Any mileage testing? More pics?

Botsapper is our resident illusionist.

That's a digitally retouched photo. (I think!! )

[MetroMPG]

Oh - also - what's that on top of your trailer, Junkie? A/C unit? Does it run while you're on the road? Do you use it?

If you don't need it, take it off. You'll reduce both frontal area (A) and drag coefficient (Cd).

If you don't need it to run while you're driving, you could fab a removable aerodynamic cover for it: round the leading edges, then on the rear taper the shape to blend it back into the trailer roof. That way you at least reduce Cd if not A.

EDIT: PS This is fun - I love managing other people's projects. Easier than actually completing my own!!

[5.0 Junkie]

Sorry on the terminology. A/c unit doesn't run during drives, but I start it to get the unit warm or cool as I have to do product demonstrations in there. It is somewhat aero, but I can likely improve a bit.

I think camper shell first and deflector on it if needed. Skirts on side fenders and possibly deflectors in front and rear of tires. How would I "smooth" the corners/top of the trailer? I'm also going to evaluate a boattail style rear on the trailer somehow.

[Christ]

Originally Posted by 5.0 Junkie

Sorry on the terminology. A/c unit doesn't run during drives, but I start it to get the unit warm or cool as I have to do product demonstrations in there. It is somewhat aero, but I can likely improve a bit.

I think camper shell first and deflector on it if needed. Skirts on side fenders and possibly deflectors in front and rear of tires. How would I "smooth" the corners/top of the trailer? I'm also going to evaluate a boattail style rear on the trailer somehow.

Boat tail nose as well. But, if you can get the topper and side spats worked out, it probably won't be so much of a problem. The idea is to keep the flow as straight as possible, so it's not "ramming" into things. If you can divert the flow so that it can make a basically straight path between the truck and the trailer, that's all you really need.

[aerohead]

I really like what botsapper put together.That would be the dream list for sure!
The trailer's front desperately needs some radius'ed edges all around,top/sides.bottom.If mine,short of a NoseCone,I get some "large" Schedule-20 PVC pipe,split in half on table saw or with a router,and attach.'
And you're saying "parachute"! Nope! Dr.Paul MacCready patented such a thing and it would help for sure.
I'd go after the gap between truck back/trailer face.Even a single vertical panel at centerline to block crossflow has been demonstrated to cut drag.
Fender skirts would be good or full wheelcovers with vents for the electric brakes.
Fairings behind all the wheels would be good but major job to fab.
MetroMPG mentioned the Coleman rooftop AC.That thing would cost 2-mpg on a car.If mine,I'd make a simple removable tapered fairing from foam insulation board and a layer of fiberglass,which tapers back to nothing,top and sides at 10-12 degrees.( carry a step ladder with you!)
With the trailer as tall as it is,you could also do an over-cab-roof shell on the truck.Thing is,match the two frontal areas as best you can.
The more gentle the curvature the better.No abrupt "eruptions".
? Does the trailer have an open ladder-type frame underneath? If so,this is another area that could save bucks if done light so as not to affect your overall gross weight.
Renault has an semi with a lower Cd than today's hybrids by covering all these areas.

[Christ]

Where's that Mercedes bubble thing Semi truck? The odd one w/ the huge glass spherical cab...