Which Trailer shape is better??

[freebeard]

Stitch-and-glue monocoque on an Harbor Freight chassis:

https://www.youtube.com/watch?v=Ref_JnT8QVY

If the kayaks made pontoons to float the cabin, that would be cool.

[aerohead]

Originally Posted by evtower

Slowmover, thanks for your post and for sharing your viewpoint. You wrote, "From my end one can see the utility of a pickup." I absolutely can see the utility and obviously an EV tow vehicle cannot possibly tow a 9,000 lb trailer that is used a primary residence. Which sounds fantastic.

But some people do live in the 17 ft lightweight trailer I plan to buy. See The Path to Less Stuff

That person is towing it with a Subaru Outback, but as I pointed out earlier it can be readily towed with a Tesla EV https://teslaxcanada.com/

My wife and I have no intention of living in our trailer. We love our house. Our trailer will be a recreational "toy" (and I understand you did not apply that term in a deragtory way .

Looks from your links that the combo 'works' and is successful on the road.
Kamm tested an automobile which had a body quite like that of the Alto,which was reported at Cd 0.45.Until such tests are done and published,we have no idea what the drag of the tow vehicle/trailer combo is.
Hope you can loosely track your kW-hr consumption on the trips,which will help us reverse-engineer some of the performance.
The EVs have 'engine' efficiencies on the order of BSFC 0.138-lbs/bhp-hr, and we may be able to correlate the EV values with that of ICE RV rigs.
I sure like the stow-able roof on Alto,which shaves off so much frontal area when towing.
ROAD & TRACK ' raced' a Tesla S and reported that the car will protect itself from motor overheat automatically,so even if you 'dog' the rig,you probably wouldn't be able to hurt it if you were trying.
This is a glimpse of zero-carbon-potential RV'ing.I sure like that!

[dancam]

Hi, this kinda goes back to the trailer shape this thread was about, but reading this thread got me excited again
So, one guy here mentioned a box over a box a few times, thats what im building. A pop-up. Except its more of a heave-up, not sure i can actually lift the top on my own. Spent 3 months on it last summer, spending 7 months on the tow vehicle and i need to be done it by the end of april. Then im back on the trailer. These photos show where i got. Im flipping the axle on the trailer so the roofline is the same as the tv. It unfortunatly ended up being 3 inches wider than the tv due to a design change miscalculation.
I need fenders for the tires. I need to move the axle ahead for better weight balance, need to build something on the front for aerodynamics. The rear was the best i could come up with at the time.
Ive been thinking for months of a good way to connect the tv to the trailer so there would be no gap but havent come up with one.
The car in the photos is not the tv but similar.
Trailer cube is 10ft long, 2 foot overhang at rear making it 12ft. Width is 5ft 3in iirc. I would have to look back in my notes at sidewall hight but closed hight off ground is 4ft9in an open hight is 7ft 10in.
Anyway, suggestions for making this more aerodynamic from where i already am would be appreciated!
Oh, this will see a 3 month 20k mile road trip in 2018.

[freebeard]

Anyway, suggestions for making this more aerodynamic from where i already am would be appreciated!

Thanks for asking, now. Slather a thin layer of aerodynamics over a brick? You're looking at the techniques applied to commercial big rigs.



One thing not included above — and possibly you best bet — is plasma actuators.

[Hersbird]

Looking good. How about just tapering that rear overhang? I see wheel pants off airplanes on ebay, they might fit those little trailer tires you would think the average expensive airplane with almost any damage to the skirts would about give the wrecked ones away. Airplane people seem to want everything perfect or its worthless to them.
I still want to redo the top on my Hi-lo but because of braces, home repairs, a new puppy, etc I probably need to sell it and my motorcycle to pay down some debt.
I'll try and convince myself I can just do better starting from scratch like you are doing.

[slowmover]

Shape is important, and I'll leave that to others better versed. Height is the highway mpg killer, before all others. After that is the need for radiused wall joins. Rolled. Top & bottom. Enclosed undercarriage. (This done, don't worry about adding Coleman Mach 8 roof air and/or Fantastic Fans).

Go have a long look at the UHaul 12'x6'x6' trailer. Great utilitarian shape. Great towing manners with tandem axle. Wide spread axle (roll center problems minimized as leaf springs are joined to axles beneath or outboard of side walls). Low ground clearance.

I used this behind my truck on two 700-mile round trips. Four legs. Two each loaded and empty. Same load. Same road and conditions. Truck is 8k solo, and combined rig was 13k. Solo mpg was always 24 (up to 27). Trailer empty was 19-mpg. Trailer loaded was 18-mpg. Always at 58-mph and never a tailwind. Gulf Coast Texas. And always traversing Houston.

About a 25-30% penalty. Doesn't get better than that. But it might with help from this crowd. Truck has cab height topper and trailer roof was same height.

I'd pretty much copy that trailer, but give it a rounded bullet nose. And an EM approved swing away tail. I'd also change to torsion axles (wheel face is now equivalent to leaf join at axle per roll center). A Towtector to build an interface upon.

And Polymetal. Somewhere. (I ain't ragging you, Freedom-of-the-Beard)

.

[freebeard]

...torsion axles (wheel face is now equivalent to leaf join at axle per roll center). A Towtector to build an interface upon.

Eh?

How did you know I was going to post this picture again? I should go out and get another scrap and try the braked edge again. Had it been scored or rabbeted on the backside it wouldn't have ruptured the outer skin:

[dancam]

I clicked to get email notifications but didnt recieve any, i thought no one had replied yet.

Originally Posted by freebeard

Thanks for asking, now. Slather a thin layer of aerodynamics over a brick? You're looking at the techniques applied to commercial big rigs.



One thing not included above — and possibly you best bet — is plasma actuators.

I did ask before i started. Based on the comment on the thread i started and what i saw elsewhere here i decided to go to a trailer building forum instead at the time. I have towed a lot but never built a trailer and needed to see a lot of other peoples builds and get help from trailer builders.
This thread here looked like it was about making bricks aerodynamic to me, so i asked.

Plasma actuators. Never heard of that before today, looks like a good idea but quite new. Thanks!
I just realized i need to keep my attention focused on finishing up my tow vehicle. It should be done in 5-6 weeks and then ill be looking into plasma actuators and everything else i need to to finish this trailer and make it as easy to pull as i can while still being functional/cheap.

Originally Posted by Hersbird

Looking good. How about just tapering that rear overhang? I see wheel pants off airplanes on ebay, they might fit those little trailer tires you would think the average expensive airplane with almost any damage to the skirts would about give the wrecked ones away. Airplane people seem to want everything perfect or its worthless to them.
I still want to redo the top on my Hi-lo but because of braces, home repairs, a new puppy, etc I probably need to sell it and my motorcycle to pay down some debt.
I'll try and convince myself I can just do better starting from scratch like you are doing.

I had wanted to taper the rear overhang like they do on semi trailers, thats where the idea came from. But as i was building i realized it wasnt practical. Thats an area to put your shoes on/do things while its raining and stay dry. When the trailer is down its already ackward to get in there without it tapered.
Also with my build materiels it wouldnt have been very strong.
Thanks for the fender idea! I was going to try and convince a sheet metal guy i barely know to make me some in that style, but hadnt thought of just buying them.

[dancam]

Originally Posted by slowmover

Shape is important, and I'll leave that to others better versed. Height is the highway mpg killer, before all others. After that is the need for radiused wall joins. Rolled. Top & bottom. Enclosed undercarriage. (This done, don't worry about adding Coleman Mach 8 roof air and/or Fantastic Fans).

Go have a long look at the UHaul 12'x6'x6' trailer. Great utilitarian shape. Great towing manners with tandem axle. Wide spread axle (roll center problems minimized as leaf springs are joined to axles beneath or outboard of side walls). Low ground clearance.

I used this behind my truck on two 700-mile round trips. Four legs. Two each loaded and empty. Same load. Same road and conditions. Truck is 8k solo, and combined rig was 13k. Solo mpg was always 24 (up to 27). Trailer empty was 19-mpg. Trailer loaded was 18-mpg. Always at 58-mph and never a tailwind. Gulf Coast Texas. And always traversing Houston.

About a 25-30% penalty. Doesn't get better than that. But it might with help from this crowd. Truck has cab height topper and trailer roof was same height.

I'd pretty much copy that trailer, but give it a rounded bullet nose. And an EM approved swing away tail. I'd also change to torsion axles (wheel face is now equivalent to leaf join at axle per roll center). A Towtector to build an interface upon.

And Polymetal. Somewhere. (I ain't ragging you, Freedom-of-the-Beard)

.

Yes, hight is a killer, thats why i decided on a pop-up instead of a one piece.
With the radiuses that was my second biggest mistake. I used 2x4's to build the frame and intended to router a radius onto all sides. I completely forgot and cant go back and do it now. Quite unbelievable really...
I am going to have to try to think of a way to round those without changing whats built.
Was planning to make side skirts, the bottoms of them should be rounded too?

With the undercarriage i was thinking cloroplast or something light to smooth it out. However i really want/don's want to put a big water tank and a spare tire under the trailer. We need a fair bit of water for our trip, i want to keep the weight low, it needs to be by the axle and i have other things i also want by the axle inside the trailer. With the spare tire too... dont want anything under there catching wind but i have to be real careful how i load my trailer to keep the tongue weight right and keep it from being a see-saw.

Thanks for the tip on the u-haul! There is a location close to me, i will go have a look at them.
I towed a 5x5x8 u-haul before i started to see if this style of car could do it. It weighed 900 pounds empty which was about as much as i wanted to pull with the hitch i had on the car. I put an extra 500 pounds in the car and headed for the biggest hills i could find. Its like a parachute but i got 25 usmpg pushing the car real hard trying to keep it at 60-70mph or whatever 5500rpm would get me to on hills. Iirc 50mph was the most i slowed down to on the biggest hill.
That was to see if the car would overheat, what my worst possible fuel milage would be, and how it handled. It handled suprisingly well considering how light the tongue weight was (only 50 pounds!) And i slowed down on an empty strech of road, went to the middle and started swinging it. Trailer was very stable and immediatly went straight when i stopped moving the wheel. I was very impressed with the u-haul!
Not so impressed with my '02 civic though. I towed the u-haul home on flat ground with it only 50km. Oil temps went super high immediatly and it blew the head gasket. I thought there was no way the little car would do it and almost didnt even bother trying. but it stayed cool that day and even stopped the trailer as fast or faster than the civic!




With the axle style- i made a hurried choice and cant return this one now.
This was a 2000 pound trailer, i plan for its final loaded weight to be 1700 pounds max. I intend to drive it like you would an otr semi at 130,000 pounds. I like that, however i dont want to be going down big hills at 20mph. I installed front brakes on the car that are nearly twice as big as oem and i bought a 3500 pound braked axle and installed it on the trailer. The axle was on sale cheap. I didnt find out about tortion axles being better till after i had installed it... Im going to stick with this axle i think. Leaf springs seem to ride fairly well when loaded near their max weight and all my weight in the trailer will be very low down. Nothing at all higher than 2ft above the floor.

Thanks for the towtector tip. I had been considering something stretchy to go from the bottom of the car bumper to the underside of the trailer to help airflow and to deflect rocks. Is that a good or bad idea?

Originally Posted by freebeard

Eh?

How did you know I was going to post this picture again? I should go out and get another scrap and try the braked edge again. Had it been scored or rabbeted on the backside it wouldn't have ruptured the outer skin:

I saw that before when i was on this forum almost a year ago, what is it? I cant remember. Can you send me a link to the thread where you talked about it?

[freebeard]

http://ecomodder.com/forum/showthrea...tml#post482424 Brought to you by the search terms 'roll' 'brake' and 'shear'.

I towed the u-haul home on flat ground with it only 50km. Oil temps went super high immediatly and it blew the head gasket.

I feels your pain. I paid top dollar for a Westfallia utility trailer; and rather than have a bad experience with it on the Interstate I rented a similar-sized open top trailer to put it in. My Squareback VW made the trip but it was never the same until an engine rebuild. Shoulda gone with a dolly.

Rather than worrying about water under the bridge, move forward and make notes for the next one you build. Torsion bars etc. From where you are now, fix the front by following this lead: http://ecomodder.com/forum/member-he...117-154543.jpg Search term 'jukebox.

If you had started the thread before the trailer, I'd have posted this (copypasta from the Permalink):



It confirms that Thee Template (this is a low resolution facsimile) is a harsh mistress.

Edit: Almost forgot: You haven't started the top yet? Squircles!