Bus roof raise aero

[oil pan 4]

I say go big it's not like your driving it to work every day.

[freebeard]

This is from my Christmas card in the 1980s



That's a sliding security grating at the bottom of the steps, there was to be an oak entry door at the top.

edit:
Wait a minute! I just realized Randy Grubb stole the Type II over White 300 design for his Deco-liner. Since it's all a fantasy, the engine is a flathead flat 12 amidships under the living-room floor.

[Keller]

Originally Posted by Piotrsko

Do you already have the bus? If not you may consider the round top bluebirds which generally went further between refuels than the flat nosed dittos that I drove.

Yes. 40' international, dt466 pusher.

Can't lower the floor. Will be adding side skirts.

[Keller]

I have allready stripped the windows out and working on stripping the interior.

I can't lower the floor. Actually the floor is getting thicker because of the insulation.

I will be adding side skirts and sloping the roof in the rear. Just dont know what to do with the front.

[freebeard]

Can't lower the floor. Will be adding side skirts.

Given the tow vehicle status does it make more sense to raise or lower it? Air bags? It would be cool to be able to lay frame in a school bus.

But whatever, ditch that fiberglass end cap with the red and yellow lights for something that sweeps back from the windshield. There is a smallish radius on the front edges, look to European trucks for their aero add-ons. Review bluebunny's thread here: canard for bluff bodied box

The rear view mirrors project forward which is good. Ditch the bumper mirror.

"95 metro 3cly 5speed 45mpg"

[ennored]

The degree of rounding the front needs is actually quite small. A radius equal 4% of the width has been mentioned before. That's a 4" radius on a 100" wide vehicle. Just need to get the air to flow smoothly to the sides and top.

Add some rear taper and you're about as good as you can get. Look at a Monaco Vesta, or Vixen motorhome. Both were designed in a wind tunnel. The Vesta had LOTS of resources behind it, way more than you have I assume, and it really doesn't have an unusual shape or features. You probably shouldn't either.

Oh yeah. Slow down.

[aerohead]

Originally Posted by Keller

I'm doing a bus build and I am raising the roof about 22"

Now the first image is what most people ha e been going to here lately. And leaving the back a strait up lift. I'm thinking I like the second strait up blunt raise for the front and will slope and transition the rear over my bed room. Or would sloping both front and rear be beneficial?

As I take it the rear would be much more important than the front. A blunt raise would alow my to mount a big screen TV above the driver head. But if its beneficial I could slope the front as well and live with a small screen.

Thoughts?

* With no leading edge radii a bus will be Cd 0.88.
* With leading edge radii equal to 5% of the square-root of the frontal area, the drag will be Cd 0.36.
* With the 'Stromform' front, Cd 0.34. And the most difficult and expensive build.
-----------------------------------------------------------------------------------
* Test data exist for buses with 5-degree boat-tailing, at top, sides, and bottom. The further back, the lower the drag. Diminishing returns at some length.
* If 'soft' edges are incorporated into the tail, you can kill off any potential vortex drag.
* If boat-tailing is done as an 'add-on', the legal limit is 60-inches of added length.

[aerohead]

Originally Posted by kach22i

See the attached rough concept.

If this is for an RV, have you studied or given thought to gutting the raised floor system?

I'm not sure how all the working parts are organized under there besides dedicated luggage areas between the wheelbase, but it seems lowering the floor could be just as labor intensive as raising the roof, plus the "A" in CdA is the same or lower should you taper off the back as shown in concept sketch.

In between the wheels the lower half of the coach interior would be "U-shaped" in cross section but the rest of the time it should just be a rectangle.

Don't think of this as removing the floor, think of it as lowering the floor.

I'm guessing that you are running electrical and plumbing under there for your new layout, leave a service utility cavity but instead of 36" make it 12".

Drive shaft and exhaust pan tunnel raises will be the immovable fixtures to work around.

The rough concept is NASA-esque. The air would like that.

[kach22i]

Originally Posted by aerohead

The rough concept is NASA-esque. The air would like that.

Keeping the area low would probably do just as much as improving aerodynamics, yes?

https://www.pinterest.com/pin/745768.../?d=t&mt=login


EDIT:

Attached a second concept where the roof is tilted back. Same original roof, just tilted because side windows are removed.

Mattress near floor, with enough room to sit up in bed, but not stand or jump on bed at about 5 foot ceiling.

Shower just enough headroom a +6 foot (allowed in building code at one time), dining area at 7 foot, living area at 8 foot proper.

Think like a yacht designer.

The thing that ruins it for RV's is all the junk they put on the roof like air-conditioners etc.

Stuff the A/C unit in lower part between the wheelbase in a well ventilated chamber, louvers or mesh screen panel covering.

I like the box-cavity rear porch area Freebeard mused about, would totally work. Heck, put a yacht-like balcony in there like a train car.

https://www.pinterest.com/pin/440226932301129829/

[cRiPpLe_rOoStEr]

I guess you would want to take a look at the current generation of Marcopolo urban transit buses in order to get some inspiration for aero mods.

Hotsite - Comienzo - MP 60 BRS - Marcopolo Ônibus