Gas Struts on C/T

Hi atoyot
Why not try Aussie Swag for advice? We have been very happy with their after sales service and I am sure Noel, Julia and James would be happy to talk to you.
I also know that they are always glad to hear from older model owners.
email them at ausinfo@aussieswag.com.au
Rusty

I have built a camper trailer. Its aluminium roof lifts up from both sides with gas strutts which I purchased from Ovesco in Sandgate Newcastle NSW. They sell just about everything for trailers boats etc. including gas strutts and are very helpful. They will work out exactly what you need and how to fit them (angles etc.) With their help mine work very successfully. They have a web site with contact details but I am not sure if they have branches in other parts of the country www.ovesco.com.au

Thanks for that; I'll check them out. It's great to here about companies that give good, helpful service these days.

Shouldn't be that hard to work out.

You should have a good clue from the research you have done.

1. Work out your closed and open gas strut lengths by propping up the top ot the postion you can still reach when open. (:-)). Not much point in it going so high you can't reach it. While you have it open check the angle. 10 deg, 20 deg?

2. Measure the load closed, this will be the heaviest load. Tuck some bathroom scales under one edge. They should be in the range of the weight, 20kg to 600kg.
I will assume 100kg for the total weight of bed and canvas. Since you are measuring one side, the scales should show 50kg.
If 50kg for one side, and say you would like to lift the lot with a 15kg effort, you need the gas strut to supply 35kg of upward effort to assist.

3. Work out the mounting points of the strut. The end fixed to the the trailer needs to be lower than the end fastened to the bed. Check the angle by measuring of the floor of the trailer and using some basic trig. Rise divided by horizontal width = tan of the angle. 50mm/1000mm = 0.05 = tan of 2.86 degrees.
Lets assume it is 2 degrees.
Also double check the closed length of the strut. may be about 1000mm.

Therefore the closed effort of the strut needs to be 35kg divided by the sine of 2 degrees. 35/sin 2 = 1002 kg. Larger the angle, less strength required in the strut, and less load on the pivot points too. Try it. 4 degrees = 501kg.

4. Do the same calculation for when open. But this time you will want the top to stay open unless you pull down with a load of 10 to 15kg. See what load other campers use.
Say it stays open at 20 degrees. Check the angle of the strut in the open position, it may be about 22 degrees.
So load for the strut when open is 50kg plus 10kg = 60kg.
60/sin 22 = 160kg.
Check the length of the strut open, may be about 1400mm.

So you need a pair of struts that are half of these loads.

closed - 1000mmm and 501kg for 2 degrees.
open - 1400mm and 80kg.

I would try and fix up a lower mount that you can move a little for trial and error.
Doing this every day, the trailer manufacturers work it out right befor ethey start manufacturing trailers.
You can see the difference 1 degree makes for the opening load.
Try a lower plate with say three holes and work the calcs on the middle hole.

Hope this helps.

Hi Andrew
Read oldplotters post great info
Don't know where you are located ??
I am in VIC, when I built my camper trailer I had invaluable help from
Struts Australia, John Bell, Ph 0393698113
John was fantastic in solving my problem with gas struts to operate my boat rack
It was something out of the ordinary but John went out of his way to make sure I was happy with the operation
AND NO THERE IS NO ASSOCIATION just a happy customer
Good Luck Barry

I am in Brisbane, so not too close to help :-).

You may find that since a gas strut generally puts out a reasonably constant force, it may not give a lot of assistance in first lifting the bed. But then since this is at a lower point, you can put in more effort yourself.
Like a boot on a car, you really want the strut holding the bed open, just. So this is your first calculation.
The assistance you can achieve in the initial lift from the strut is a bonus. That 2 or 4 degree angle makes a big difference here.
Of course your problem is that you don't want the strut hanging down inside the trailer to block access, which results from a lower mounting point.
So maybe the front strut (one closest to the draw bar) inside mount point could be lower so the front strut gives more help with the initial lift? Just thought of it last night, but I havn't seen it down this way and wonder why. Maybe being in the trailer just behind the front wall of the trailer it may still get damaged by something moving around on a bumpy road.

Good luck. And the strut people are very helpful. I always check with them before finalising a design I do in the office.

PS - one little trick mounting struts. Always mount them upside down so that the rod is down and strut body up. That way the oil in the strut stays against the seal and keeps it in a good condition. The strut people should tell you that.