Thread: Enclosed Trailer design

Hello all,
I have decided to have a crack at designing and building an enclosed trailer for carrying our UAV's and incorporate a built in GCS . This will be my first time at building a trailer so it would be much appreciated if you provide me with some advise.
The trailer will be 4.7m x 2.1m x 2m, dual axles with brakes on one set only.
I have designed the chassis with the following materials;
Draw bar RHS 100x50x3 and the chassis 70x50x2.
The enclosure will be made from SHS 25x25x2 and covered with 4mm aluminum composite panels.

I'm not sure if I have the wheels in the correct location and have put them with a 60/40 ball weight.

TIA

What is a UAV and a GCS.

Dual wheel brakes would be better, I had brakes on one set and they were not bad but since puting them on both sets they really help pull up the ute better and keep everything nice and straight. Dont cost much more to do it now.

Sorry Jim for the acronyms, UAV - unmanned aerial vehicle and GCS - Ground control station.

Thanks for the advice on the extra brakes and I will get a quote for them as well. I haven't purchased any of the materials yet.

Originally Posted by Jim Carroll

What is a UAV and a GCS.

Dual wheel brakes would be better, I had brakes on one set and they were not bad but since puting them on both sets they really help pull up the ute better and keep everything nice and straight. Dont cost much more to do it now.

Originally Posted by Jim Carroll

What is a UAV and a GCS.

I'm assuming that UAV is an Unmanned Aerial Vehicle and GCS is a Ground Control Satellite or System?

If this is the case, you could probably reduce the 75x50 to 50x50, as the rest of the frame will provide the strength and rigidity required.

a wild guess: Unmanned Arial Vehicles and Ground Control Systems?

Thanks for the replys to the uneducated. still trying to get my head around LOL etc.

If I were designing it I'd try and treat the whole thing like as a monocoque.

Rely on the sides of the body to provide stiffness to the chassis and hence keep weight down.

If you sheeted the sides up and welded or glued the panels to the frame you would end up with a very stiff but light structure.

I'd guess your finished design is going to weigh around 800k/900g empty.

Originally Posted by zuffen

If I were designing it I'd try and treat the whole thing like as a monocoque.

Rely on the sides of the body to provide stiffness to the chassis and hence keep weight down.

If you sheeted the sides up and welded or glued the panels to the frame you would end up with a very stiff but light structure.

I'd guess your finished design is going to weigh around 800k/900g empty.

With all that framework, it's going to be like a monocoque anyway, but the difference with a trailer is that with all the weight being supported around the middle, the stresses on the frame will want to tear it apart from the top, whereas a car with a monocoque chassis, the weight is supported at the ends so the stresses are in compression.
Have alook at most Caravans. These days quite a few companies are building them with an aluminium skeletal frame, but they still use two hefty chassis rails.

If you do lessen the chassis rails, It will be more critical for you to tie the drawbar back to the spring hangers. You dont need the centre drawbar either... ever seen a Caravan with one?

As for the brakes, the average 10" Electric brake is good for 1600Kg, and this is the upper limit of its capacity, so while it's legal to have only one axle braked at 2000Kg ATM, you'll find it seriously lacking when it comes to a hard stop. If you cant stretch the budget to brakes on both axles straight away, then at least order the axle with the mounts fitted. This way, the second set will bolt straight up.

Originally Posted by Yonnee

With all that framework, it's going to be like a monocoque anyway, but the difference with a trailer is that with all the weight being supported around the middle, the stresses on the frame will want to tear it apart from the top, whereas a car with a monocoque chassis, the weight is supported at the ends so the stresses are in compression.
Have alook at most Caravans. These days quite a few companies are building them with an aluminium skeletal frame, but they still use two hefty chassis rails.

If you do lessen the chassis rails, It will be more critical for you to tie the drawbar back to the spring hangers. You dont need the centre drawbar either... ever seen a Caravan with one?

As for the brakes, the average 10" Electric brake is good for 1600Kg, and this is the upper limit of its capacity, so while it's legal to have only one axle braked at 2000Kg ATM, you'll find it seriously lacking when it comes to a hard stop. If you cant stretch the budget to brakes on both axles straight away, then at least order the axle with the mounts fitted. This way, the second set will bolt straight up.

Seems to me that triangulation in the framework could be applied to this design.

Does that UAV get Hellfire missiles, too? I'd mount them somewhere safe in the trailer for transport.....

Do you think my chassis rails are too small, do I need to increase them?
I will also look at putting brakes on all wheels.

I am also having some trouble designing the doors so they are weather proof, do any of you guys have any pictures on how this is done. Thanks for the advise so far.

And no the UAV doesn't carry hellfire. If you are interested in seeing our UAV have a look here,
[ame=http://www.youtube.com/watch?v=3WtDcAAOZjo]Avitus Petrel UAS.mp4 - YouTube[/ame]

Originally Posted by Yonnee

With all that framework, it's going to be like a monocoque anyway, but the difference with a trailer is that with all the weight being supported around the middle, the stresses on the frame will want to tear it apart from the top, whereas a car with a monocoque chassis, the weight is supported at the ends so the stresses are in compression.
Have alook at most Caravans. These days quite a few companies are building them with an aluminium skeletal frame, but they still use two hefty chassis rails.

If you do lessen the chassis rails, It will be more critical for you to tie the drawbar back to the spring hangers. You dont need the centre drawbar either... ever seen a Caravan with one?

As for the brakes, the average 10" Electric brake is good for 1600Kg, and this is the upper limit of its capacity, so while it's legal to have only one axle braked at 2000Kg ATM, you'll find it seriously lacking when it comes to a hard stop. If you cant stretch the budget to brakes on both axles straight away, then at least order the axle with the mounts fitted. This way, the second set will bolt straight up.

I found some extruded aluminum channel and 20mm composite panel today which would completely remove all the 25x25 frame work. Have any of you guys used this stuff before?
The only problem is the price, the panel is $90 /m2 and the extrude is expensive.
This is the stuff I found;
http://www.uesint.com/upload/pdf/Alu...Extrusions.pdf

Do you know of other suppliers of the stuff?

years a go I saw refridgerated meat trucks that used a sprayed fiberglass over the matting for the sides and roof no frame just the fiberglass and they had 10 ton of meat hanging from the roof plus the cooler unit on the front and had no problems with the sides cracking and the door seals were air tight

Try Universal Engineers Supplies at Regency Park for all the components you need to do dust/water sealing hinges locks etc.
Kryn

Originally Posted by Avitus

I found some extruded aluminum channel and 20mm composite panel today which would completely remove all the 25x25 frame work. Have any of you guys used this stuff before?
The only problem is the price, the panel is $90 /m2 and the extrude is expensive.
This is the stuff I found;
http://www.uesint.com/upload/pdf/Alu...Extrusions.pdf

Do you know of other suppliers of the stuff?

Yes I have made a trailer from the stuff UES sell. It is very exxy and it can be a pain in the behind to work with. Trailer looks good in the end but the biggest drawback is the sizes of the panel at 1200mm wide.

UES get it direct off the importer so I doubt anyone else will have it. All the extrusions fit together nicely and look good, but lotsa $$.

There is different products around but none that look as good as that