Foamie aerodynamics.

[mezmo]

Hi Bogo,

Check these links out:

http://www.goldbrand.info/
http://www.goldbrand.info/motorcykelhusvagn2.html

Almost Deja Vu ?

Cheers,
Norm/mezmo

[DriverOne]

I have two questions.

1- Would a wing that was a raised copy of the surface providing downward force at the airflow break-off point in the tapering curve of a teardrop do better to assist airflow in continuing along the surface of the teardrop, or would the blade act more like a parachute?

2- Would this application prove beneficial on the underside of the trailer?

[wagondude]

As to question 1, downforce is aditional drag. A wing to smooth and help prevent flow separation might help, but would be difficult for tha average person to get right.

for question 2, a belly pan would help, but probably not enough unless you panned the TV also. A number of big trucks are using wedges to direct the airflow under the axles of the trailers with good results. You could also get a similar effect with skirting on both vehicles, but it would do little good to do the trailer by itself. The entire combination has to be considered to get maximum bennefit for the effort required.

http://www.truckpartsandservice.com/fil ... edSled.jpg

[Wobbly Wheels]

1- Would a wing that was a raised copy of the surface providing downward force at the airflow break-off point in the tapering curve of a teardrop do better to assist airflow in continuing along the surface of the teardrop, or would the blade act more like a parachute?

If you recall, SUVs and minivans had them for a while. Were the mileage increased significantly enough for people to notice, you can bet that we'd still see them....despite the trend toward rounder jelly-bean bodies overall.

[Bogo]

2- Would this application prove beneficial on the underside of the trailer?

That's not just a belly pan. It is also a diffuser. It too is designed to generate down force and thus would increase drag. There is no need for one on a trailer.

[Bogo]

http://www.goldbrand.info/
http://www.goldbrand.info/motorcykelhusvagn2.html

Interesting. It's allot lighter construction than I was thinking of using. I've been planning on 2" thick foam walls because the double pane window units I want to use have a nearly 2" deep frame depth. Because they go on the top lifting part, the window frame can't protrude inside. I'm also expecting to use some wood or metal framing in the top and bottom. Going to making my own windows and using integrated frames is a possibility, but I'd need to have a way for them to open enough to stick a big camera lens out. That way I can use the trailer as a camera blind.

The 2" thick foam walls will provide allot of insulation., but I need to have a bit less window area to interior volume than my house has. I made a very air tight super insulated house with a large south facing window set, and an east facing sliding glass door. My house will easily gain 15F on a sunny winter day. Then at night it only bothers to loose 1/2 degree an hour.

[GPW]

Insulation is the Big benefit of Foamies ... used as much as possible ...Allowing generous rounding /carving/smoothing which eliminates the sharp drag producing edges...

While you’re chasing down Drag .... much to be considered about those two wheels sticking out ... Very draggy, more air to displace ... Problem solved on early airplanes by the use of "wheel pants" (later retractable landing gear , not practical on trailers
Makes one think of those full fiberglass fenders (with fender skirts) that wrap around the wheel ,much as wheel pants, probably doing much to smooth the flow ...
Many little drag producing things to consider .. sometimes just a compromise in the end between a really Good idea , and the ability to build it ...

[rowerwet]

another trick used on electric/solar racers was to go with very thin high pressure tires, as sidewall flex is also drag, and the aero foot print of the tire/fender is much less. it would be interesting to see how skinny of a tire would support a trailer.
of course that would take a really great spring package to make up for the tire hardness.

[GPW]

... and maybe some add on shocks on my street (er, dirt road) Thin tires ? What’s the thinnest trailer tire you could get ? Foamies are Light !!! It’s the Beer that’s so Heavy !!!

[DriverOne]

I've seen motorcycle trailers with what looked like bicycle wheels. I bet you could use them on a teardrop.

[wagondude]

For an unbraked trailer, you could use spindle mount dragster front wheels. But I doubt you would find any DOT legal tires for them. Custom wheels could be made to fit any conventional hub that would use motorcycle tires, but cost would be the issue there.

[Bogo]

For thin tires I'd look at motorcycle side car tires. The issue then becomes finding wheels to suit. If a motorcycle side car wheel was used, check it's weight loading capacity. Motorcycle tires are not made for side loading, but the sidecar tires are.

I'd look at some of the really small cars and use the same tire. That way spares are relatively easy to locate. Check to make sure you can get wheels that have bolt circles that are compatible with trailer hubs.

One of the tires I've thought of using is the Prius tire and wheel, but finding compatible hubs for trailer axles has so far eluded me. I see it listed as using a 5x100mm bolt circle which is slightly off (1.6mm) the 5x4" bolt circle I see listed for trailer hubs. Are they different, or did Toyota just call it 5x100mm when it really is 5x98.4mm?

[Wobbly Wheels]

One of the tires I've thought of using is the Prius tire and wheel, but finding compatible hubs for trailer axles has so far eluded me.

Why not use the Prius trailing axle:

This one's from an eBay listing for $400 - not much more than you would probably pay for an axle, hubs, and brakes. The beam itself appears to be a sheet metal tube, so shortening (narrowing) it shouldn't be a deal breaker. The geometry suggests it might incorporate a sway bar inside...but I'm guessing not.
Priuses (Priii ?) have been around long enough and there are enough of them out there that they must be plenty in the wreckers' yards by now.
I worked in a yard when I was younger and we used to sell Caravan/Voyager ones to trailer builders all the time (though they were leaf springs).

[Bogo]

Using a Prius axle would also require using most of the rest of the Prius's rear suspension geometry, and it's hydraulic braking, not electric.

[Wobbly Wheels]

Not if you use surge brakes.
The suspension depends entirely on your fab skills.
If it's worth it to you to use Prius wheels, it's a doable project. After all, it's just a trailing axle.