Teardrop Trailer

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mrjoshm
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Teardrop Trailer

Post by mrjoshm »

hello,
i'm not sure if any of you have ever built one of these but i want to build one. it seems like a lot of people take the easy way out and buy a 4'x8' harbor freight utility trailer for their frame..they weigh 250-300 pounds with the 8" and 12" wheels and finished teardrops are between 1000-2000lbs. i am not familiar with trailers but i want to make my teardrop as light as possible. i am not going to add cupboards or drawers or anything that adds weight, i'm going to keep it as simple as possible. i'd like the finished product to weigh 750lbs at the most and ideally 500lbs. i'd also like to use full size wheels since i will be putting a lot of miles on this thing but maybe my lack of knowledge here is wrong and the dinky 8" wheels are suited fine to 1000 mile trips at highway speeds, but general logic leads me to think they wouldn't be. it would also be nice to utilize all of the spare MK2/MK3 VW parts i have laying around like stub axles or even aircooled stuff since i have a spare torsion bar front end... i'm not sure if any of that will equate into light weight or is practical and if it is just impractical then i'll buy an appropriate axle. i just wanted to ask if any one here had any insight or advice. i have a lot of 1.25" square x 1/16" wall ERW tubing too that i am using to build my locost frame but i wasn't sure if it would be appropriate to use since most guys that build their own frames are using 2" x 1/8" wall tubing but they aren't going for light weight since their finished product is 1500lbs+.

any help would be great

thanks
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Warren Nethercote
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Re: Teardrop Trailer

Post by Warren Nethercote »

If you want to keep it light you may need to avoid recycled suspension, such as your left-over VW front end. A tube-frame, stressed skin teardrop body should be much better than the usual 'house on a ready-made trailer frame'. I would use torsion suspension to allow low ground clearance and a clean interior, not to mention lighter weight.

Princess Auto (a Canadian source, by way of example only: http://www.princessauto.com/truck-trail ... n-axle-end ) is one poossibility. I'm sure JC Whitney or even the ubiquitous Harbour Freight has them, although British sources would have 'lighter duty' ones that would be even more suitable.
ted andkilde
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Re: Teardrop Trailer

Post by ted andkilde »

Can't give any real-life advice but I like the look of teardrops as well. Seems like they would make a good "companion" project to make the seven more practical for road trips to the track and whatnot. Good place to toss a toolbox, a tent, a set of R-compounds and a jack.

I'd try to fit wheels with the same rolling diameter and bolt pattern as the car so you could share a spare.

You could probably build lighter than a typical utility trailer as long as you weren't planning to haul any significant weight around. You might need some strategic beefing up where the leaf springs and hitch point mount up.

Perhaps hang your hitch off some "shock tabs" on the chassis so you could make it removable with a few pip-pins.

t

Just as a side note, anyone know why trailers never seem to have shock absorbers fitted? I've always thought they would tow better if they didn't bounce around as much, but I've got nothing other than supposition to base that on.
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jdgar0649
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Re: Teardrop Trailer

Post by jdgar0649 »

I've admired for a long time check this out:

http://www.teardrops.net/index.html
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maxlessca
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Re: Teardrop Trailer

Post by maxlessca »

The final weight with will depend on a lot of things. Don't expect to have a useful camping trailer that weighs 500lbs, unless you use an inflatable mattress with helium in it for the bed, and you don't have much else in the trailer. What are you going to make the body out of? Wood or aluminum? If weight is a concern, use actual trailer parts for the axle and suspension, as oppose to the VW parts. They are light, and very easy to put together. The easiest way is to buy a Harbor freight trailer and use its components.

It is a good idea to have the larger tires. I've had a couple of 8" tires blow out on me at highway speed, and since then, I've avoided using them.

If you do decide to build this, keep us posted on how it goes. I know that I would be very interested in seeing your progress.

A good source for trailer parts is http://www.northerntool.com/webapp/wcs/stores/servlet/category_6970_166839 They have everything you need to build a trailer, except the steel. There are other places, such as Harbor freight, but northern tool is a good starting point.


Good luck!
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SportsCarDesigner
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Re: Teardrop Trailer

Post by SportsCarDesigner »

ted andkilde wrote:Just as a side note, anyone know why trailers never seem to have shock absorbers fitted? I've always thought they would tow better if they didn't bounce around as much, but I've got nothing other than supposition to base that on.


Cost. And nobody on board to get seasick :lol:

But the rubber torsion axles use the rubber as both a spring and a friction damper if I'm not mistaken. And you can clock some of them such that the frame can ride low like the early teardrops.

Image

Traditional teardrops are heavy 'cause they use a ton of 3/4" plywood, then cover with aluminum sheet. Build frame and shell Locost style with thin tubing and bond/rivet aluminum skin on.... should be able to keep it 1/3rd weight of your Locost?
.
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dodgedartgt
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Re: Teardrop Trailer

Post by dodgedartgt »

I have also paid a lot of attention over the years to TD trailers.
I'll second the previous opinions about using trailer specific torsion axles. I haul my zero-turn riding mower around on what used to be a 60's-70's vintage StarCraft brand pop-up tent trailer. The stripped frame only weighs about 250 with wheels before I started to add the decking.
In my case, the hubs are 4 x 4". I have 4.80 x 12" tires, but Vega/Sunfire/etc use 13" x 4.5" have the same bolt pattern. With a deck surface of 75" x 80" and a single piece torsion axle assembly, it would make a great basis for a build.
Mike
mcteardrops
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Re: Teardrop Trailer

Post by mcteardrops »

check out http://www.mikenchell.com/forums/
From my bucket list:
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a.moore
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Re: Teardrop Trailer

Post by a.moore »

When I was buying my HF trailer, I found a bunch of site related to the teardrop trailers and thought it would be a cool project someday. I haven't made it that far yet but apparently great Locosting minds think alike.
KB58
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Re: Teardrop Trailer

Post by KB58 »

Actually the teardrop shape generates all sorts of lift. If it were simply inverted... if anyone cares.
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dodgedartgt
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Re: Teardrop Trailer

Post by dodgedartgt »

KB58 wrote:Actually the teardrop shape generates all sorts of lift. If it were simply inverted... if anyone cares.


Hmmmm... Less tire wear. :lol:

Mike
zetec7

Re: Teardrop Trailer

Post by zetec7 »

Want less weight AND less tire wear? Don't fill 'em with air! Use helium... (I know, I know...just kidding! :roll: )
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aero_bro
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Re: Teardrop Trailer

Post by aero_bro »

KB58 wrote:Actually the teardrop shape generates all sorts of lift. If it were simply inverted... if anyone cares.


I was thinking the same thing. At highway speeds a trailer that shape would generate enough lift to become rather unstable. Flipping it and making it generate downforce would be better for stability, but would also generate massive drag and increase fuel consumption and tire wear.

Now if one were to make it actually "teardrop" or airfoil shape, or even with just with an upturn at the back, the aerodynamics would improve significantly. It's a trade off between stability & safety or gas mileage.

Ken
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mrjoshm
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Re: Teardrop Trailer

Post by mrjoshm »

how stable, how much drag, would there be a difference... if the tear drop had a 2' kamm tail at about 22° with a 2" lip at the end of the fast back like my CAD™ drawling?

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egoman
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Re: Teardrop Trailer

Post by egoman »

Say that the 2 inch spoiler worked. You have a adequate amount of tounge weight and the trailer is towing nicely . As the speed increases the spoiler starts to add a little down force and because the down force is added behind the axle centerline the trailer gets light on the tounge. As the trailer starts to sway allmost uncontrollably we accelerate to get it back in line, but the affect of the spoiler makes it get worse and you are in a hellacious wreck.
By the way accelerating out of the sway condition has been the solution for many years. Works the same for a speed wobble on a bike.
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