No Chassis Build

[Creamcracker]

I've seen a number of plans for sale where the teardrop is built without any metal chassis. Basically it looks like the wheels are bolted directly to the wooden floor. Just wanted some feedback on this method of construction. I searched the archives but see nothing that addresses that construction method.
Philip

[asianflava]

You must have not searched that hard. This is a hotly debated topic. Put "frameless" in the search bar and you'll find plenty.

[Creamcracker]

Thanks "Frameless" was not a word I would have tried!

[PaulC]

Mike was doing an ultralight that I seem to have lost track of. His idea was to build it in the way you describe.
Cheers
Paul

[angib]

Yep, 'frameless' or 'ultralight' should find the all-wood discussion.

However I would say that building an all-wood trailer should not be considered if you think it will be less work than building a steel frame - actually it will be a lot more work, as many of the joints need to be much stronger than if there is a frame underneath.

This does not mean that I think a full steel frame is necessary. In fact there are only two metal components that I think are important:

1) The tongue or A-frame. You can build these in wood, but it's very difficult and you need at least the skills of, say, a boatbuilder. Trying to do it without using epoxy for the joints strikes me as dangerous.

2) The axle mounts - an axle, whether torsion or leaf-spring, produces point loads that wood is not the best thing to handle. Again, it can be done in wood, but really it's much easier to put in a small amount of metal. All that's needed is a couple of feet of angle or tube under each sidewall. With a leaf-spring axle, some transverse strength is also required, but with a torsion axle it isn't.

If you draw out a sensible arrangement of A-frame and axle mounts, they very nearly meet in the middle - you might as well extend them until they do meet and then you get a basic chassis. Mixing the 'all-wood' discussion with another historic 'bolt-together frame' discussion, we might even be able to bolt this frame together.

A first thought (not a build recommendation) looks like this:



Anyone want to comment/shoot down/laugh?

Andrew

[dwgriff1]

Mine is built with a pan and no frame. The axle is bolted diretly to the pan. It has about a 650 miles on it so far and it works wonderful. I am a SOB, but I think a steel frame is redundant.

Bear in mind what Andrew says. It won't save time, and it might not save much weight, but it is a fun challenge.

In spite of this being the minority opinion, I think there is a great future for this style of construction.

Besides the tongue considerations, remember to provide plenty of meat where the axls will bolt.

dave

[Jiminsav]

Did mine without a frame, just used some 2X3 1/8 inch steel for the tongue and for two cross pieces that bolt to the ribs on the bottom, thusly.


also used a piece of 2X10 Oak timber to bolt the axles too..ain't budged yet.

[del]

Andrew

this is what i had in mind for my simple frame (to bad i did not find this then). would i need cross member(s) to use a leaf spring?

[angib]

would i need cross member(s) to use a leaf spring?

Probably not. But that is not quite the same thing as definitely not!

I'm not concerned about any loads tending to push the red frame pieces apart - it's twisting of these pieces from a sideways load on the axle that I'm thinking about.

If the two red frame pieces were securely bolted thorough both the floor and the wall, so that they couldn't twist, then I doubt a cross-member is needed.

Andrew

[mikeschn]

A strong wind came up and blew my little Ultralight over...



But more importantly than that, look at the tongue that the light of the day revealed... looks kinda familar eh?

Mike...

[angib]

A strong wind came up and blew my little Ultralight over...

And now you're going to have to get your widest chisel really sharp to get those pads off the bottom where the single tongue was going to go.......

What? You say this is only a simulation?

Andrew