Thread: Help needed to design a...

righteyo, fire away!

Quick buggar aintcha!!

so first problem is the width... to wide mate come down to about 8ft 2in I think thats pretty much the standard width before she would need to get a permit in each state to tow it

Next the length 30ft??? strewth!! I was working on 20 maybe 24ft take into account the length of the winnibango mate and youve created a bloody semi trailer rig! this could then create another licensing issue for her in that some galah in one state or another would make her sit her semi license to drive the thing

mmmm okay height? mmm I reckon your about right there given the height of a winnibango

Keep at it me ol china yer doin well

1. Use the space above the car bonnet for a storage mini-loft.
2. Add a door on the driver's side of the trailer to accommodate the open door of the car; otherwise you either have to push the car in, or climb out the window and then slither through the trailer to the back.
3. I think even small cars are more than 10ft long.

Joe

what about this then for overall dimensions?

What is going to be towing it?

You would only need 6' internal height. You are working outside most of the time.
Take the walls out to the outside of the wheel arches, gives more storage area.
Put a nose cone on the front, another storage area as long as it is light gear because when they check they go by the ball weight.

Having driven the car in the box how do you open the door to get out.

Originally Posted by martrix

what about this then for overall dimensions?

What is going to be towing it?

Im not sure but I think the overall width is around 8ft 4in? including wheels and wheel arches... as I said Im not sure but think thats the way its done

A winnibango

Id imagine one of them all in one units... dont know the motor size as she didnt say... an mate Im only tryin to get things rolling here.. I'll give her a hoi an see what she reckons when she reads the thread

Joe I'll go measure the missus proton "beast" an get back to you... not sure shes got a proton but hey its a small car eh!

For the vehicle widths, the max width allowed is 2.5m (8ft 4in) as per the australian vehicle standards bulletin

There is also a maximum length of 12.5m but that incorporates the towbar length as well.

sell the car and buy one of those double decker buses, kit it out, and precilla queen of the woodchucks here we come.....simple

A lot of the snowbirds we see around here have the motor yacht towing the car. Don't know the brand, but they use a nifty tow bar that folds back against the front bumper; doesn't have to be removed.

Joe

Does it really need to be a fully enclosed trailer? That's a lot of extra framing and sheetmetal (= weight) plus mucking around building doors etc. On something that size the frame will wrack a lot against the doors which don't and you get stress cracks in the framing, chafing of metal against metal with resultant ugly rust marks.

I reckon that an open car trailer with a box on the front, shaped for air flow would be the go. The box can house all the "toys" and will protect the vehicle from stone chips and should deflect most of the diesel haze around it.

The starting point of the design exercise should be the what the maximum weight of ther trailer can be. The tow vehicle will have a maximum allowable tow weight, plus a maximum GCM (Gross Combination Mass). You'll need to know what the gross weight of the mobile home will be when fully loaded (fuel, water, food etc etc) to see how much of the GCM is left to play with, because with some vehicles Gross Vehicle Mass + Towing Capacity is greater than GCM. ie, you can have a fully loaded trailer or truck, but not both. Next thing, have either of the drivers had much/any experience driving a combo of the length and weight we're looking at here? Do they want to go to the trouble of getting the appropriate licenses? Do they want to drive a heavy combination around the countryside? It's a lot more tiring than driving a car, requires more concentration, room to maeuver, space to stop and park, fuel, registration, etc etc etc.

Once you've gone through all of that and you knwo how much your trailer can weigh and how much the run around will weigh you'll need to look at appropriate axles, springs and brakes and the weight thereof. For the dimensions, the first thing you need to know is what size the vehicle will be. It's going to be aq very different trailer if you want a Suzuki Jimny as a run around as opposed to a Pajero.

I would look at paring down, as much as possible what's considered a must have to bring along. I'd try to fit it all in the tow vehicle and just have a small run around riding on a two wheel dolly trailer and a protective "car bra" fitted to the runaround to minimise stone chips etc.

A large heavy trailer is no fun to tow. It's not for nothing that trailers with rigid draw bars are referred to as "pig trailer" in the transport industry. Trailers with drawbars that swivel the front axle(s) are called "dog trailers" because, like a good dog they'll faithfully follow you. Towing a heavy pig trailer is like trying to take a pig for a walk on a lead, it's hard work and the pig wants to go its own way.

Actually, I'd look at whether a ruanaround was strictly neccesary. Think about push bikes, motorbikes or even motorised push bikes.

Mick

Originally Posted by journeyman Mick

Does it really need to be a fully enclosed trailer? That's a lot of extra framing and sheetmetal (= weight) plus mucking around building doors etc. On something that size the frame will wrack a lot against the doors which don't and you get stress cracks in the framing, chafing of metal against metal with resultant ugly rust marks.

The answer to the racking and general skin movement on the frame is glue. I have just built a second enclosed trailer which has very little framing except around the dorr entries and mid length along the sides, though it is smaller than the one proposed. The first one showed signs of cracking around the rear door and was not rigid enough, the second was bonded with Sikaflex and it is rigid. We glued everything including the floor to the chassis and it is far better than mechanical fixings of which some were used but not many. All the panels were made in a CNC controlled sheet metal factory including the chassis members which we folded ourselves. Just remember it must be complianced before registration so I would tackle that issue first as we had to get ours inspected by a certifying engineer before the registration authorities would look at it.
As to the woodworking part of it, don't forget to allow for exhaust extraction, this will need it as the air will be stalled in a very small area with the same amount of dust as in a larger shed. It is going to weigh A LOT and I would be sitting down and carefully working out if the finished trailer was towable legally with the intended vehicle. There are small and large Winnebagos and it will have to be one of the larger ones to have a trailer of this size. I drive trucks for a living and don't think I would like to drive around Australia towing a trailer of this size if it were me. I wonder if there is a legal allowable length limit on something like this?

If it were me I would talk to the manufacturer, Winnebago, they should know the GCM etc.
There are quite a few of them towing trailers and would be able to advise where to start.

As an ex-trucky the best advice I can give is that this must be made by an engineer, one who knows what he's all about in the trailer world.

The old 8 feet and 2 inches wide was the absolute maximum allowed for the drivers side mirrors. If the trailer is that wide, the mirrors will not mirror the road behind your trailer. This unit will be daunting to drag along, especially if these people are inexperienced tow drivers. For a load of tools and stuff, the construction will need to be stronger than a caravan. A cross-wind, or one from either front corner will test the drivers skill.

In any case, recent trailer law changes have been made in most states, and if you visit your local State Transport Department website, you can find all of the info required. Don't forget your licence, does it caover the wieght and combination?

Something like this will involve special tow bars, full braking system and the overall length of both tow vehicle and trailer as well as weight, both laden and unladen . . .blah blah blah. After all, it is the Government who has all the say in this matter. After them comes the insurance man.