Ultralight Design?

[PaulC]

Hi Mike, any possibility of making this thread a sticky. This has got me off the weekender and I can see some awesome possibilities with this.

If i get it stuck somewhere 2 people should be able to manhandle it out, up or down
Cheers
Paul

[mikeschn]

Sure thing...

and here's where I'm at, modeling wise...



Mike...

[weasel]

Mike are usin' a springs? If so why not build a axle out of 2'' tubing and buy new hubs or use rear hubs off a front wheel drive GM. I was gonna build mine till I got one for $50. My axle weighs 75#, one out of 2'' with hubs should be lighter and as strong. But if the body is light it don't need a 1500-2000#axle. One more opinion, still think I run 1'' tubing around the bottom to tie axle and springs to keep from flex. Light and strong.

[mikeschn]

You bring up another good question... The 3 ply springs that I got with the 1175# trailers are going to be too stiff for a 400# trailer.

So what would you guys do, remove 1 leaf or two?

Mike...

[Mitheral]

You bring up another good question... The 3 ply springs that I got with the 1175# trailers are going to be too stiff for a 400# trailer.

So what would you guys do, remove 1 leaf or two?

Mike...

Seems resonable. I'm concerned about what is going to happen when I get two adults plus a two year old and all their clothes, say 350-400 lbs, in a trailer sprung for 400 lbs.

Jacks of some sort might be required.

[MeelisV]

like mine

these brackets are standard for trailer like these.
http://www.bestnet.ee/haagised/?lisa=hi ... gis&jutt=2
from there i bought mine axel and those brackets too. easy mount your axel with frame.

[bg]

You bring up another good question... The 3 ply springs that I got with the 1175# trailers are going to be too stiff for a 400# trailer.

So what would you guys do, remove 1 leaf or two?

Mike...

I'd start by removing one. I'll be removing two, but then again I'm starting with a pair of 3500 lb springs(4 Leafs).

[mikeschn]

I got the wheels on, and realized the fender didn't do a very good job covering the wheels. So I moved the fenders out. They now bolt up to the wood framing.

Of the two tongue methods that Andrew presented, I like the straight tongue better. Yes, the tabs are going to have to be welded to the tongue, but any muffler shop can do that.

Here's what it's looking like...



And since I know some of you are itching to spin this thing around in space, here is a wrl.

http://www.mikenchell.com/Ultralight/ul ... light4.wrl

All you need to view this file is a free Internet Explorer/Firefox plugin called "Cortona". You can get it here... http://www.parallelgraphics.com/products/cortona/

Have fun...

Mike...

[angib]

For anyone who's a bit flummoxed by the x,y coordinates, I've done a profile pdf for the Ultralight in my usual format. It contains the ellipse and arc geometry as well as the profile in traditional 'squared paper' format:



One note of warning: the door opening is not identical to Mike's - the top is the same (3" offset from the roof), but the bottom frame is shown at 3 1/2" high.

Andrew

[mikeschn]

Thanks for doing that Andrew... that's a big help...

Weight... are you wondering how much an ultralight weighs? I am too, that's why I am modeling like crazy...

Here's what I have so far...

2 side walls with fenders = 88#
1 torsion box floor = 21#
1 axle and 2 springs = 31#
2 angle asms = 18#
1 tongue with bar stock = 20#
2 wheels with tires = 46#

so far the running total is: 224#

[alaska teardrop]

I got the wheels on, and realized the fender didn't do a very good job covering the wheels. Mike...

A pair of smooth aluminum round fenders sure would look nice.

[mikeschn]

Fred,

It would be easy enough to do...

The builder just has to add round framing around the fender, and attach to that.

I can see many variations of the ultralight...

framing inside instead of outside
painted instead of a woody
aluminum instead of a woody
modernistic fenders
homemade modernistic fenders
round fenders
diamond plate fenders
torsion axle instead of leaf spring axle

and the list goes on and on...

Mike...

[GregB]

Mike and Andrew,

I have been following the Ultralight development with great interest, but primarily for information regarding the frame design. Do you think that this latest frame design with the tongue not attached to the axle structure is robust enough for a full weight, (i.e., 1000 lbs. dry) trailer? I plan on using torsion box construction for floor, sides and ceiling which, once joined, should make effectively a monocoque body.

After rereading Andrew's posts, I am led to believe that this frame may be adequate for most of the tears on this board, since all it really has to do is transfer the force from tow hitch to wheels and keep the body over the wheels. Sorry if this is a digression, but the Minibago wants to know.


GB

[mikeschn]

Greg,

I'm going to let Andrew chip in here, as he has a better feeling for this stuff than I do.

But I will say that working with Andrew the last few days has been very revealing...

The biggest thing I learned is that the axle supports need to be attached to the side walls, not the floor. Andrew showed me a t-molding arangement that did that very nicely. If I can find the pictures, I'll share that with you.

The other thing I learned is that only the front most and the rear most tongue bolts are effective. All the bolts in the middle don't do a thing. So Andrews's design welds a plate onto the front of the tongue and the rear of the tongue. So now we have two bolts instead of one, at the most critical locations. And any muffler shop can weld those plates on.

I think I need a little more wood where the tongue connects to the torsion box, but I would feel pretty good about any trailer less than 1000#, as long as you have a piece of bar stock on the inside of the cabin... shown here in red...



Mike...

[bg]

Mike, If Chell liked my first picture, She'll love this one.



Yup, that's my axle and modifed springs, on my old dining table.

Axle is 40 lbs, springs are 4 lbs each.

Welp, the steel supply opens at 8, I'll call in my order and head over there.