Theater Trailer

Hello, dear forum frequenters

I'm an amateur builder in need of your expertise.

I want to build a charriot that opens up into a stage, something like what is seen in The Imaginarium of Doctor Parnassus but smaller. I would like to join an itinerant street theater company next year and I will build a tricycle to pull this trailer around. The bike will be operated by two people pedaling and one person steering. I'm comfortable working with steel and bike parts, so no help required on that regard, but when it comes to the trailer...

I would like to make it as light as possible. I am thinking about using aluminum, a metal I've never worked with before. I know welding is out of the question, but I reckon bolts will make strong enough connections. The idea is to build a metal frame and then use the thinnest plywood, methacrylate and cardboard for the walls and ceiling, and thickest plywood for the floor. The size being 3m by 1.5m, 2.4m height.

I'm mostly worried about the flooring. The idea is to have two surfaces to walk on, the floor of the trailer and a wall that will be pulled down when the trailer is stationary. I'll just use big ass hinges and three to four unfolding legs for the later one.

Here is my question? What size of aluminum tube would you use and how much can I space them? I assume round tubing beats square tubing, but I might be wrong. And the maximum spacing is affected by the thickness of the plywood sheets, which I'm also ignorant about.

Any help regarding this questions will be mostly appreciated,

Looking forward to start working on this foolish dream and sharing the process with you :)

A rough sketch of what you intend to make would help, as it's not clear what load the floor has to carry, and over what span.

In general a square or rectangular profile is more efficient as a beam than a tube, so depending on load and span, you could use 50x25 RHS on 450 or 600 centres with the spacing dependent on the thickness of the ply, and how much flex you're prepared to accept.

Is your theatre going to be part of the pedal bike or as a trailer?

As a basic design you'll need to construct something like a cube.
Because you're "trailer's" going to be 3 metres long, I'd use something like 75X50 thickness possibly 1.6mm to keep the weight down, 75mm being the vertical. For the cross members I'd go for 50X25, depending on the thickness of your board (10/12mm??) spacing could be 400mm centres.
Your outside frame, the one that opens, again I'd use the 75X50X1.6, with mitred corners to gain maximum strength. The rear frame, make it out of 50X25X1.6, as it will be plenty strong enough with the cladding. Use 25X25X1.6mm for the cross pieces to tie the front and rear together.
Your other floor that hinges down, you could use 50X25X1.6 on its edge, and 25 or 30 square 1.6mm for the cross members. The legs will probably need to be adjustable, as footpaths, kerbs etc, are never level. Depending on how much your budget is, you could use a couple of screw scissor jacks, or go for the smaller quick release adjustable leg.
HTH.
Kryn

Your description of this project as a "Foolish Dream" is probably correct as I doubt that this human powered contraption would be allowed on any road in Australia, if in fact you are in Australia, because your location does not give any hint of where in the world you are exactly.

Welcome to the forum.

As mentioned above if you are in Australia there are pages of regulations and laws you need to comply with, you need to start with at the least a rough drawing
and then there is the issue of insurance

I would forget the methylacrylate as it's too brittle and will eventually break in this application. A substitute could be polycarbonate (PC) which is more UV resistant and much tougher enabling thinner sheets to be used. Rolls of PC can be bought from Bunnings ($140 for a 5 x 1m x 0.8mm roll), it's not cheap but it will outlast acrylic by a long way

What I do know is a fold up stage would be quite heavy. Theres the supporting framework then the flooring you stand on to begin with.

Made a marquee roof to suit a larger stage than what you propose. (foldup unit that is trailer mounted). From memory was at least 5mtr x 5mtr when unfolded. If I find the fotos on PC then will upload.

Setup was heavy as.

Film makers have occasionally been known to 'visually mislead' (that is, cheat). For a stage to pivot down like that, in real life there would probably need to be a counterweight on the on stage side to keep things stable.

Michael

Hi Krokanti,

Firstly let me welcome you to our Metalwork Forum. There are a great bunch of people here and willing to help where they can.

While, it is not my intention to chase you away on your first post with us but to be honest, you have made it a bit difficult for members to address your inquiries.

Location is really important in helping frame a response to questions asked as some regulation often applies.

The Lookup to your ISP number indicates you are in or near Switzerland.

There are lots here on the forum well versed in trailer building but I doubt many can advise on European road trailers towed by a bicycle and regulations pertaining to them.

Here in Australia a non commercially built trailer requires inspection before it is allowed on the road.What applies to your location is unknown to us.

May I suggest that you make inquiries with the pertinent authority for your location as I think there will be much they can tell you which will impact on your intended build.
From there the blokes here will be able to help more with the nuts and bolts issues.

Again, welcome to the forum.

Grahame