Trailer thread! Teardrop builders wanted.
 

Were I to build this myself, it would necessarily come after the full Coanda-effect kit on my panel van and turning my '58 Beetle into a redwood Zeppelin. So I release this under Creative Commons Attribution 3.0 Unported* for anyone who wants to build a teardrop, but doesn't know how to get outside the 'box'.

What defines a teardrop? I would suggest
•simple-curved aerodynamic shape
•one-sheet floor
•no standing room
•side hatch entry
•body narrower than the wheels
•rear kitchen

What I propose
•simple-curved approximation of The Template
•since I'm cutting the sheet, I cheat with a 4x12 or 5x10 sheet
•I propose to stretch the template in the Yth direction — 150 to 200%
•move the entry to the truncated boattail
•tandem wheels on a single axle
•5 out of 6 ain't bad, integrated water storage

I've worked with geodesic domes so I'm used to approximating curves with straight lines. The template could be rendered as a low frequency triangular faceted asymmetrical dome, as I did with the wooden motorhome design. In this case I start with a hexagon base and curved vertical edges. The 60° angles become 45° in front to accommodate jack-knifing and 22.5° in the rear to give a good closing angle. The tail is truncated to the size of the door. The various possible [straight or] curved edges mean the shape goes all wiggly-wobbly compared to a geodesic shape. Straight edges result in a Template semicircular arc, a 5' wide body would have 2 1/2' of headroom. A deep curve would result in a Conestoga-like wide body.
http://ecomodder.com/forum/member-fr...17-trdrp1a.jpg

One thing I once owned that went down the road to an hopeful new owner was a 1952 Silver Streak Clipper. I don't have the trailer today, but I do have a measured drawing.
http://ecomodder.com/forum/member-fr...iler-show0.png
The quarter-spherical end caps use tightly gored material, narrow strips in simple curves and lots of seams. The thing I like about the construction of that trailer was that the frame was a 5" diameter center spine with 6" C-channel crossmembers. And that was it—each crossmember terminated in a carriage bolt through the plywood deck An aluminum C-channel the same thickness as the skin material was screwed to the upper surface of the deck to carry the inner and outer wall skins. The outer skin was aluminum and the inner was steel.

http://ecomodder.com/forum/member-fr...iler-show1.png
A second influence is the Bowlus Papoose. I saw a 20-footer when I was in college, and they sell 35-foot Bowlus Road Chief replicas for $100,000 (or try to). The Papoose is 16 feet long, that's getting into teardrop territory. It's one of those cases where it would go faster backward. :)

Another influence is these pictures I found of a trailer called The Roswell.
http://i.imgur.com/hWpF9Be.jpghttp://i.imgur.com/tkf9WWk.jpg

What this suggests to me is to use the hexagonal-pod construction (a design that goes back at least to Domebook 1, if your interested) to get a low-resolution highly-streamlined shape that because it uses the simple curves and has one flat wall is IMHO technically a teardrop!

So using the construction of the Silverstreak frame and extrapolating from the single-trailing-arm suspension on my Westphalia utility trailer, this design extends the Roswell concept in three ways:
•The door and it's associated framing is moved from the thin-walled side, to a flat truncation of the Template shape.
•The Stretched hexagon plan of the Roswell is made asymmetrical. The front angle is 90° to allow jack-knifing, and the rear angle is 45° to get the 22 1/2° optimum taper in the rear. The profile is level from the center [skylight] to the top of the door.
•The suspension consists of a dog-bone arm (sort of like a double-ended front motorcycle fork) that pivots on an axle stub and carries a wheel and tire on each side. The design scales from a 4x8 on 4ea 8" wheels to a 5x10 on 10" wheels or even a 5x16 on 12" wheels.

Small versions might be unsprung. More advanced version would have rubber in torsion and disk brakes or kinetic recovery that dampens the ride by charging a battery.
http://ecomodder.com/forum/member-fr...-trdrp-frm.jpg

The center tube could double as a water tank, with the weight carried low in the center. 3 to 14 gallons by my calculation. The back of the Buck-Rogers-fin-like flat Trophenwagen-style fender top would flip out into a seat on either side of the door or a bench along the side. The rear bumper folds down into a step beneath the door. Kitchen (if any) would be over the hitch, the reverse of normal teardrop practice.

Cross section could be anything from the 5x2.5 aerodynamic optimum to 4x4 or as big as 5x6, and it could be squircular! I think once you widen the body and enclose the wheels it's not really a teardrop, although 4/5x6 would look something like an horse trailer. If the wheels were at the center section, half wheelwells could fit in pretty neatly, making shelves in the interior.

This leaves a lot unsaid, construction materials (PolyMetal vs corrugated vs burlap/hoops), center of balance, central skylight bubble vs trolley roof, & etc,. & etc. I choose to stop here.

'What do you think, Sirs?'



*This work is licensed under a Creative Commons Attribution 3.0 Unported License. Creative Commons — Attribution 3.0 Unported — CC BY 3.0

think
 

I'd like to see a road-going version trekking down the highway for a real-life experience.It would ask the RV'er for less sacrifice than some of the stuff I'm cobbling together.
The upper curvature looks real yummy after seeing You-Tube of square-edged travel trailers blowing completely over in a crosswind!:thumbup:

aerohead! Tag, you're it. :rolleyes: As you say you have a history with this sort of thing. I have a history of having trouble getting other people to build my ideas.

On that first model the edges are 4', 3' and 5' front to back. I started with the center section 3' long and the center at 18" to get the 135°/2 and 157.5°/2 angles to the center. The result is a short 'thorax' and a long 'abdomen'.

I'm currently making a 2nd model, same scale, same 10' length but on a 4x10 sheet. The edge lengths will be arbitrarily 4',4', and 4'. Also the wheels were pushed back so they could be tucked inside the max width; but I think teardrops are like that because of the weight of the kitchen in back. So the new model has the wheels in the (newly longer) center section with semi-enclosed wheelwells and half-fender/spats. And it will be skinned with corrugated material.

If someone was building one, I might go back to the 3D modeling and compare squircles at 45° to each other.

If I did build one myself, it probably would be based on my Westy utility trailer. I have a source for the (thoroughly thrashed) suspension parts via thesamba.com. It's a 4'x3'x1.5 box. Some redwood bows with temp bracing, with burlap shrunk to fit and sprayed with clear polyurethane would get me in the game. :cool:

Have you thrown together a model WITH the tow vehicle to look at airflow? Maybe you could fit in more interior space on the front if it's within the template. Of course you'd want to accomodate about 15* of yaw in the air flow as well.

I was imagining a boat hull type construction with longitudinal wood slats. That would look fantastic.

http://www.woodenboathouse.com/_images/design_long.png

Another thing to think about would be integrating the wheel pods into the body. I was thinking you make the standard 40's style wheel and skirt, but then extrude it into the body. Kind of like this Topolino dragster I saw a couple years ago, but with skirts.

It would eliminate the aero uncertainty of the "tunnel" between wheel and body. Of course, you'd want to make a legitimate teardrop instead of this stylized mud guard.

http://farm7.staticflickr.com/6089/6...f534925956.jpg

Thanks for thinking about it. I basically threw together a few ideas—the shell, the frame and the suspension—that are really independent. Hanging two wheels on a single suspended pivot is probably the least viable. It's intended to reduce the frontal area for the wheel and tire, and *might* work retrofitted on any teardrop.

Likewise the Silver Streak frame detail could be applied to any teardrop.

The compound curve wood strip construction is optimal, but I was trying to work within the stated teardrop parameters. Your suggestion could work on this frame and suspension.

Here's how Bowlus handled the fenders:
http://ecomodder.com/forum/member-fr...iler-show2.png
But I like the idea of a flat-topped fender that folds out into a bench or table.

I'm back from a road trip so maybe I'll make progress on the 2nd iteration. On the other hand, I have a design for a teardrop that would scale down to bicycle or motorcycle size that is the traditional flat-sided shape. I'm not sure where people's interests lie.

Pimp
Subscribed

dremd -- Darn—now I gots to get off my butt.

I didn't address this. It intended to be generic, but it's 1"=1". I'll look for a Barbie doll. :)

The three straight segments are distributed along the teardrop curve. That's really low resolution. Overlaid in 2D the two corners overlap about as much as a circle overlaps a square of equal perimeter. The Classical problem; squaring the circle, via eyeball engineering.

Adjusting the relative side lengths changes the angles.It happens that with ~3, 4, and 5ft sides the front angle is ~45° and the middle side are parallel. If you sharpen the nose the middle sides taper to the rear, for instance.

Cross section at yaw angles is less, is it not? OMG

I've thought of similar, starting with a ~$200 cheapo 4 X 8 open flatbed trailer from Northern Tools or Harbor Freight, the kind that folds and stands on end to take up less garage space.

Replace the cheap Chinese bearings and wheels/tires on day one, because they're worthless.Use Coroplast for the Conestoga wagon sides and roof, to act as wheel skirts and partly enclose the wheels for better streamlining. No point in wasting that space and having the wheels make extra drag. Insert fiberglass or aluminum tent poles into the flutes for stiffness. Extend the floor forwards to cover the folding tongue of the trailer, no reason to waste that space. Extend the floor aft to act as a loading ramp and to be the base floor for the teardrop tail. Use Coroplast for all skins, essentially shaped per your model shown above. Make a fairing to cover the axle below, turning it into essentially an airfoil shape to reduce drag.

This would be a sorta mini-horse trailer, with teardrop rear. Great for hauling motorcycles, and/or as a camper trailer.

Could probably do this project for less than ~$500 if all new stuff, considerably less if you can find the basic trailer on Craigslist or similar.

Otto -- Thanks for taking the time.*

...but, I've thought about all that, like you, and I'm trying to move beyond that. For instance:

•the frame. A central spine and a few crossmembers, one doubled up to make an axle inside the shell, incorporating a water tank and step/bumper. It's a sub-frame inside a monocoque shell. Added windows would be like in Burt Rutan's airplanes.

•aerodynamics of the wheels? I choose to reduce the frontal area of the wheel/tire and create a low frontal area dual-use fender. The tandem wheels could have a connecting fillet and Moon disks.

•Coroplast. I was intentionally vague. Alumacorr is aluminum skinned coroplast, but it still doesn't take abrasion as well as PolyMetal, for similar weight. Grimco MaxMetal has thicker skins. (Links on request)

Hey, plywood ribs, stringers and cedar shingles laid longitudinally and lapped vertically, with the ends bandsawed like fish scales. :thumbup:

In coroplast's favor, the stiffen ribs could also pin the curved sections together. Welding rod tack welded end to end 12' long and bent twice.

If/when I get back to model #2 it will be 3-3.5' tall with a 'trolley top' of 8-10" to get away from that horse-trailer look.

*Had I gotten vanity plates for my Notchback Type III, they would have read OTTOBON. :)

I have had one of the 1720# HF trailers for 10 years without bearing failure hauling all sorts of things. I DO repack the bearings at the beginning of each season. I also had one of the lighter 4x8 trailers with 10" wheels for 25+ years with no failures there either.

BB

Possibly you're responding to http://ecomodder.com/forum/showthrea...tml#post385716 at permalink 211?

Tag you're it
 

Years ago I was 'gifted' a 21-foot fiberglass sailboat by Lake Dallas Marina.All I had to do was get it to my place,where it's languished longer than I'd like to admit.
Reversed,inverted,and raised a bit,she''l be a somewhat heavy,but robust gooseneck trailer shell for a tandem axle subframe.
It will be like a larger 'Papoose',with fully-integrated wheels.
The existing prow makes for an ideal boat tail.The transom is extremely robust and will facilitate attachment of the hitch mechanism.The Lincoln stick-welder is waiting on me for materials to construct the rotisserie she'll be mounted to for the buildout.
If we can have 'boat car' art-cars,we can have boat-trailer RVs.:)

Which comes first, the rotisserie or the pre-preg carbon-fiber body kit?

__________________
I posted this at http://ecomodder.com/forum/showthrea...tml#post372117
http://ecomodder.com/forum/member-fr...18-1-28-50.png

At #15-#18 Frank Lee and I discussed an upside down transom-first single-wheel trailer. Could you hold the single wheel back [forward] toward the middle to improve maneuverability? Maybe an electric in-hub motor?
__________________

Edit: Now that I think on it, castering and propulsion would be A-B switched. :eek:
__________________
Edit the 2nd: If the hinge line is at mid-transom, the excursions would be minimized and you could suck up closer to the tow vehicle.

first/wheel
 

*The rotisserie comes first.
*On my 1-wheeler,I went for tongue weight as a guide for wheel location and it ended up about centered under the body.It's awkward utility wise,but it was just a proof of concept project.
*And now that the CRX is back in service I'm eyeing the 1-wheeler a bit harder.I never got to complete it or testing.
*I saw 48-mpg average through three states at speeds as high as 80 mph.
*The carburetor had a vacuum line completely breached and she ran rich enough to leave soot down the side.
*With vacuum restored and gap-fillers,I think I'd see some tasty numbers.
*With your trailer as you and Frank have created it,I think you'd really like it.

What I've been thinking about for the last day or so is this:

The distance across the middle of a VW Beetle windshield is about the same as center to center on the tail-lights. If I took a roof clip from a Beetle (cut 27" down from the crown, I measured) and pie cut it so the back window and vents are gone, it would make a teardrop the height of the rear fenders. Ultracapacitors to the rear, a caster wheel with hub motor on a bulkhead built off the old door frame, and the space between the old door windows could be a cargo compartment. The electronics would be sized to capture and expend kinetic energy, probably controlled via wi-fi.

teardrop
 

Your Sawsall/plasma cutter/welder would have a good time!

More like the Lasso and Shear tools in Photoshop, But I do have a SawZall. :thumbup:

I still want to put the solar collector on the roof of the trailer I'm in before the weather turns. But then I think it's time to move on.

40' insulated aluminum shipping container, $7800 delivered in the local area. Cut the middle 32' out (to qualify for a Recreational trailer license) and pie cut the floor and roof leaving a lip in the wall that can be spot welded after the cut and shut. 1 foot radius on the front with a 6' picture window. 6' pie cuts in back, truncated with a 4' sliding patio door set, with 4' barn doors on 2' 4-bar links that store along the sides but swing back to complete the boattail.

It would be as much space as I have now, but with 8' ceiling and no rotten plywood floor. I going to scout out the dealer tomorrow, but I'd probably have to find work to finance it.

Bucky Fuller
 

This would be kind of a new slant on Dymaxion House!
Delivered by derigible? No road or runway necessary!:D

When I was on Long Binh Post, there was a field full of double-wide trailers between my hooch and the motor pool. Every once in a while, a Chinook would fly over and jerk one of them into the sky. :eek:

Or maybe put it on needle shaped catamaran hulls, like his racing shell?
http://www.modavivendi.com/wp-conten...-needles-w.jpg
If the needles were submerged you'd have a SWATH hull.

When I went to Google Images for a picture of the catamaran, I found this:
http://klaustoon.files.wordpress.com...ham1.jpg?w=545
It has Reyner Banham's bubble house in the upper left, Bucky's Dymaxion front and center and Smurfs in the lower right. There's a whole series that gets off topic, e.g. Banham Syle/Gangnam Style parody.

Poor neglected thread. :(

Well, I got a scanner/fax/inkjet for $16 (before the discount). My first print shows it needs only one of the five colors and my first scan shows an anomaly on the right side. It will be fine for Kodachrome prints.

http://ecomodder.com/forum/member-fr...d-image-1.jpeg

I mentioned this back at Permalink #5:

The top bows are based on the design of an old Model T touring top, with the three top bows supporting a waterproof or even inflatable top. Everything below that could be multiple layers that roll up: rain-fly or mosquito netting. Straps would allow rolling up both/all layers to open it up in nice weather.

The cabinet (or shelf) that folds out can create a platform as long as the bed of the trailer. Scalable from bicycle-size on up, it could be flat sided or curve sided to the point the top would be like 1/3 of a torus. The hinge line is far up the back enough that the top/floor lies on the 'transom' to take stress off the piano hinge.

This is more of a 'travel' trailer than a 'camping' trailer. I figure if you can get gas you can get food.

Two years later and I still don't have a trailer hitch.

So are you still gonna go in the direction of a single swivel wheel setup? ;)

I'm just trying to get a coat of paint on my roof rack. I'm thinking lately instead of waiting until I have a trailer hitch, I should just refurbish the frame of my Westfalia trailer (needs to be done, anyway) and replace the box with a 3x6ft piece of swingdoor material. A teardrop would fall together pretty easily at that point. I can always borrow a tow vehicle. Right?

Here's the corner of the next page in the sketchbook:

http://ecomodder.com/forum/member-fr...13-9-20-42.png

A Beetle is 48" across at the base of the windshield, but it doesn't have enough taper so it would have to be pie-cut. It's shown with a half-door with a quarter circular basket on one side and a slide out bin with a porthole on the other. The old windshield area is concave so it can snuggle up close.

It would have a Vespa front fork machined to turn in complete circles. If it sticks through the top that would be a perfect excuse for a tail fin or shark fin.