Funny little trailers

[angib]

I would build it so the bottom was enclosed for aero purposes

I'm not sure if that would be a big benefit - sure, it must be better than a load of cross-members sticking down, but if the tow vehicle doesn't have a smooth bottom, then I think there must be a limited benefit from doing it to the trailer.

Andrew

[Arne]

Andrew, could be. I'm taking my lead from race cars with long skirts that almost touch the ground. since that isn't practical with a tear, I figured the best thing was to enclose it. Any tear will detract from mpg as it will always add drag. The thing is to keep it to a minimum.

I've even thought about the bottom of my current tear. enclosing the bottom would be tedious, but putting a piece of 1/8, say 10 inches long, in front of each xmember would be pretty easy. the piece would be flat to the floor bottom and curve down to end under the xmember, screwed in front and held in place at the back by it's own springyness..... that would ease the standing static air down and under each xmember and might be a minor help at 65 mph....

The airflow coming off the tow vehicle and under the tear has to be quite aero-dirty and anything that would smooth the flow would be better than adding more turbulence.

[Gage]

Andrew, they used to make a single wheeled trailer with a double hitch on the bumper, one hitch on each end..... you might be onto the world's first single wheel tear, with the wheel between you and your sig. other.. and you wouldn't be able to open the tow vehicle hatch.... and it might fall over when you disconnect it.... minor design problems to be overcome....

but i think it would cut down considerably on the wind resistance with just one wheel..

................. ................

[Chris C]

The only problem with single wheel trailers is: If they are too long, it is like a Black Lab Retriever's tail back there behind you. When turning in constricted areas you can literally sweep things out of your way like a bull in a china shop.

[asianflava]

- The trailer should not be too 'awkward' a shape - remember that even the closed tailgate of a pickup affects drag and that's a long way inside the wake of the cab.

Not meaning to hijack this thread but:

I've heard that the tailgate thing is a myth. SCCA used to race trucks a while back. I was watching a race where they asked the Archer brothers why they run with the tailgate up. They said that it made no difference, I figured that they ran with it up so they didn't loose some advertiser real estate on the truck.

One year, I tried an experiment when I drove home for Christmas. I drove from Durham NC to Central FL (a 700 mile trip) with the tailgate up then back the with it down. There was no change in milage. When I got a tonneau cover I did notice a chance.

A while back, one of my magazines (I don't remember which) did wind tunnel experiments that confirmed my findings. They found that aerodynamics were worse with it down. I just did a search and found it:
http://www.popularmechanics.com/automotive/auto_technology/1266911.html?page=5&c=y

Also found this:
http://www.awtrucks.com/tailgateup.htm

[angib]

Asian,

Thanks, those are interesting links. That'll teach me to use an example from another country. So now if I edit my previous post to replace the tailgate example with your tonneau cover example, your post will then not make sense. So I'll leave it as it is!

Andrew

[R Keller]

- The trailer shoud not stick out beyond the wake of the tow vehicle. Note this includes the underside of the tow vehicle - the trailer should ideally not go below that.

Oh no Andrew! Now you'll just convince a lot of us on this side of the pond that we need huge tow vehicles to tow our small trailers so as to hide the trailer in the wake of the vehicle!

Am I right or am I lost??? IF i'm right then wouldn't the rounded and sloped rear of a traditional treardrop be very efficient?

I'm no expert either, but I don't think a rounded or sloped rear is necessarily more efficient aerodynamically. Unless you're getting in the range of a 20-degree slope back there ("fastback"). Koenig-Fachsenfel and Kamm showed in the 1930's that many times a blunt "cut-off" tail is more efficient than a tapered one. Something to do with keeping the airflow attached better (less turbulence). A cutoff shape can mimic the effect of a full gradual taper by leaving a small low pressure area and good laminar flow at the boundaries. I'm sure Andrew can enlighten us further...

Plus, for teardrop trailers, we're just talking about the curve looking from the side. Most (all?) of them have flat sides that do not taper at all from front to back, so offer no aerodynamic advantage in that regard.

Rik

[jay]

"One year, I tried an experiment when I drove home for Christmas. I drove from Durham NC to Central FL (a 700 mile trip) with the tailgate up then back the with it down. There was no change in milage. When I got a tonneau cover I did notice a chance."

but isn't florida to north carolina uphill...?

[donreby]

And don't forget head winds. Christmas headed north into a north wind!

[donreby]

And don't forget head winds. Christmas headed north into a north wind!

[asianflava]

And don't forget head winds. Christmas headed north into a north wind!

Oh yeah I used the heater more on one trip. My spark plugs and oil were older on the second trip add to that NC sold "Oxygenated" gas in the winter. The air temp had changed during that week so my mass air flow sensor told the computer to send a different mixture to the engine, and I had to plow my truck thru denser air.

It wasn't a perfectly controlled experiment I never claimed it was. I just did it for my own edification. You could say it was the geek in me. Even then, there was no difference in mileage.

Sheesh you guys.

[cracker39]

If you can't stand in it, it's a teardrop. If it's shaped like a Grasshopper, it's just not a traditional teardrop but it's still considered a teardrop. Some people here on the left coast get real sticky about what a teardrop is and still let a grasshopper 'style' teardrop in Teardrop 'only' gatherings.

WOW...what technical terms I see here "Aerodynamics, thermodynamics, coefficient of rolling friction, estimated Cd range, reverse-engineered, Supercallifragilistic-expialidacious, and the angle of the dangle and square of the root."

Boy, did this thread go off on a tangent. What I want to know, is that if I show up at a TD gathering in my TTT, will I be ostracized just because we want to be able to stand up in it? Or, can I park in another loop and walk over to visit? I just wanna be friends...

(music playing) :M:M:M
We can't play this game anymore
But can we still be friends
Things just can't go on like before
But can we still be friends

Oh well, I still like you guys even if I don't have a TD.