Building a Wooden Trailer

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Re: Building a Wooden Trailer

Postby tony.latham » Fri Sep 07, 2018 5:07 pm

I think it's doable. But I'd diagram out what it looks like canted 45º and hitched to your car. I understand why you want to close the gap but I too think the tongue is too short.

What if you sell your Civic and buy a C-RV in three years? Will there be room for the hatch to open?

I would cover the underside and sides with PMF to reduce the likelihood of water getting into the frame as I don't want it to rot.


Epoxy would do a better job of sealing. As long as you don't live in the jungle, "the mix" would work fine too.

Tony

p.s. Here's my 'drop running in a wind tunnel of sorts. Note there is no dust boiling out between my Tacoma and the cabin. A gap of about 54".

Image

I would think if I had air burbling and adding drag between my truck's bed (and camper shell) I'd see dust in front of the cabin.
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Re: Building a Wooden Trailer

Postby QueticoBill » Fri Sep 07, 2018 7:10 pm

I think this will work fine and be strong enough, as it should be.

I suggest you look at the Am Plywood Association design manuals on stressed skin.

The one thing I'd research a lot is the steel to wood fasteners.

I wonder if the C3X3.5 seems possibly oversize.
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Re: Building a Wooden Trailer

Postby timm » Fri Sep 07, 2018 11:08 pm

Here's what it looks like rotated by 70 degrees.

Image

The yellow line is where the ball of the hitch will most likely be. Even if the ball is a little closer to the car I should be fine.

Image

I won't be switching vehicles any time soon, but there probably wouldn't be room for the hatch to open. There is enough room for the car's trunk to open though.

What is "the mix"? Epoxy would be nice but it's expensive.

I haven't done any simulations with a Tacoma model, but here's a simulation of a normal teardrop and a Civic. There's 34" of separation between the trailer and car.

Image

There isn't a huge amount of swirling air, but there is a pretty large increase in drag force. Just the car is 265 N whereas with the teardrop the drag is 707 N (about 2.65 times the drag). I'd imagine the increase is smaller with the truck as the roof is much closer to the roof of the teardrop.

Thanks for the tip on the stressed skin manuals. I'll take a close look at those later but they look to be helpful.

I've run some stress tests on the channel, yep it's a bit too much. I can swap it out for a 1.5 x 1/16" square tube. Here's the simulation if you guys are interested. 6 different types of beams, simulated with ASTM A36 steel and a 600 N (about 135 lbs) load applied. I'm guessing the tongue weight will be about 115 lbs max so a safety factor of a little over 2 should be fine.

Image

Weights of the beams:
a - 6.34 lbs.
b - 5.85 lbs.
c - 5.24 lbs.
d - 11.69 lbs.
e - 15.94 lbs.
f - 12.13 lbs.
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Re: Building a Wooden Trailer

Postby swoody126 » Sat Sep 08, 2018 7:46 am

:MLAS
Last edited by swoody126 on Sat Sep 08, 2018 1:14 pm, edited 1 time in total.
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Re: Building a Wooden Trailer

Postby Ottsville » Sat Sep 08, 2018 8:43 am

I think your tongue should provide enough strength on the front of your spring mount angle, I would move the crossmember from just behind the tongue to the backside of your spring mount angle iron.

On your tongue metal, are your stress test simulations only assuming load in one direction?
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Re: Building a Wooden Trailer

Postby tony.latham » Sat Sep 08, 2018 11:29 am

Here's what it looks like rotated by 70 degrees.


I know you can make this work.

:thumbsup:

Planning.

Tony
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Re: Building a Wooden Trailer

Postby timm » Sat Sep 08, 2018 12:23 pm

I'm not 100% set on building a wooden trailer, I'm just not seeing any problems that can't be fixed. I don't think it's fair to compare what can be done with modern construction techniques to a horse-drawn wagon. I can look for old bed rails or try and scrounge up some steel but then I have no idea what kind of steel it is, I don't want to weld my trailer together only to discover that the steel I found wasn't good enough.

A used trailer is an option, but then I'm likely going to be extending the frame with wood anyway. I also don't need a 2000# capacity trailer for a teardrop that isn't even going to weigh half of that.

I could move the angle to the rear of the spring mount angle pieces. I wasn't sure where would be the best spot for it.

That stress test was only downward, but I've run others in a variety of directions with very similar results.

Thanks Tony
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