Considering a camper trailer

^ I already have a lot of detail shots uploaded to my web site. I will have another look at them and see what's missing. Shouldn't be too many that I've missed, but there will be some when looked at from your perspective.

Your trailer is also going to be different as a result of ending up under a different kind of tent.

Correct me if I'm wrong, but as I now understand it, your RTT folds out to the side and you sleep crosswise, i.e. at right angles to the length of the car/trailer. If so, this will also govern the design of the trailer.

Which side does it fold out to, D/S or P/S?

[EDIT]

Most are already uploaded. Just need to duplicate the relevant ones into a coherent set in another album.

Need to take a few detail shots of the chassis and springs from underneath.

I have been thinking about how to lift your RTT to an appropriate height. Perhaps either a scissor lift ( X ) or an elbow lift ( < > ) with slide locks over the pivot points. The lift process could be assisted by 4 appropriate and appropriately placed gas struts. The pressure, length and placement of these needs very careful consideration. It took three goes and re-gassing to get mine right!

Any method of doing this requires that you can seal off the trailer tub from both the elements and casual thievery! So I suggest that you keep the two design aspects (relatively) separate. The lid can also serve as table space when camped. Perhaps simple drop-down canvas sides that are attached to the underside of the base board of the RTT would fulfill this requirement. These could be in 3 (or 4) separate sections, joined as desired with broad Velcro stripping. This is how the main annex roof is joined to my CT tent body, and the entire sun room annex has 3 individual walls, a trailer rear infill panel and a floor that can be assembled like Lego as required or desired.

[end edit]

Thanks for the spreadsheet RB.

My RTT folds out on the drivers side currently as I like having the awning on the passenger side (that way I never hit MY head on it). When the RTT is on the trailer I will spin it 180 so that it folds out on the passenger side also to make a more compact camping unit.

I hadn't considered the need to protect the trailer tub from the elements once the tent is raised, one for the next design revision.

The Tent will have to be raised 650 - 700mm from its traveling height to its deployed height - I have a few designs but nothing I am sold on. Keep the suggestions coming, I hadn't even considered gas struts.

Gidday ST

I found the other photos I mentioned ...

stilson said:

Thanks for the spreadsheet RB.

Click to expand...

No worries, mate. My pleasure.

My RTT folds out on the drivers side currently as I like having the awning on the passenger side (that way I never hit MY head on it). When the RTT is on the trailer I will spin it 180 so that it folds out on the passenger side also to make a more compact camping unit.

Click to expand...

IMO, this makes for a safer arrangement if one has to camp anywhere near a roadside for whatever reason.

One reason I chose the CT tent I did was because my trailer lid already opened on the D/S (i.e. hinge pins are on the P/S), and the Oztrail Camper 6 opens on the P/S. This allows the trailer lid (complete with tent) to be opened for access to the trailer bed whether the tent is stowed or erected.

With your setup, RTT instead of camper trailer tent, you might want to consider hinging the tub lid down the centre.
There are many other permutations and combinations of allowing access to the trailer tub even when the tent is in the stowed position.
One idea is that you could hinge the base board off the trailer top, but this would be impossible once the tent is erected. Also impossible to raise the RTT ... DOH!
Another way is how the base board on mine is configured. The entire base board lifts when the trailer top is opened, regardless of whether the tent is stowed or erected, but the base board and separate trailer lid both have holes in them now. The mating surfaces are weather and dust sealed. The tent base board has a fairly big hatch that allows access to much of the tub when the tent is erected, without opening the trailer lid. This access is from inside the tent - i.e. under cover.

When the trailer lid is shut and locked, one cannot remove either of the Jerry cans ... :iconwink: :biggrin:. Designed that way about half way through the process!

I hadn't considered the need to protect the trailer tub from the elements once the tent is raised, one for the next design revision.

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It's these 'little' things that you do need to get as right as possible during the design phase. By good luck or accidental good management, I didn't get too many things wrong. All were or are fixable at minimal expense.

My biggest problem was the mis-match between the CT tent and my trailer. Like yours, there was about a 200-300 mm hiatus that wasn't covered. This bothered me for months. Then I worked out the solution. It cost me some extra weight (but stronger ... ) and about $300 to fix it properly.

The Tent will have to be raised 650 - 700mm from its traveling height to its deployed height - I have a few designs but nothing I am sold on. Keep the suggestions coming, I hadn't even considered gas struts.

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The gas struts on mine started out at 700 N, but have been re-gassed to 1,000 N after several changes of position ... The top can now be lifted pretty easily by just myself. Most importantly, I can also pull it down shut! I use a box section safety strut when it is open, even if just for a short time. Having been king-hit by the Camry's bonnet once has made me very wary about relying on gas struts, no matter how convenient they may be.

I will try to duplicate the relevant photos into a single album later today.

Appreciated, I've read every page of your trailer thread(s) but trying to locate certain relevant images would send me mad!

^ I know exactly what you mean!

Inside track of my Fox is 1240, tub width will be 1200 or slightly less to give clearance. I've decided to reduce length to 1400. I am now using a 4% load space axle back spacing - 60mm.

The rear frame crossmember will be a C section that will house the number plate and tail lights and protect them from impacts.

Could I get away with 1.2mm floor and sides if I pressed contours in them for rigidity?

What is the distance from the front of the drawbar to the McHitch pivot point?

^ The tub really has to be 1220-1225 wide.

Shortening the tub it will not really solve your problem.

Has your RTT got any protrusions below the base board? If not, then the trailer lid poses very few problems.
Mine was so bloody difficult because of the various 18-20 mm protrusions on the underside of the tent base board ... .

[EDIT]

The ability to get into the trailer bed without either raising or erecting your RTT can't be stressed too highly. It is all but impossible to load or retrieve items through the rear gate, and mostly there will be a toolbox in front of your front gate.

Another option for your RTT is to mount it sideways, at the very rear of the trailer top, with the opening part facing rearwards. It is 1400 mm wide in this orientation. My CT tent is nominally 1500 mm wide, but bulges out a few inches at the sides, It is still well within the overall width of the trailer guards.

Just a couple more thoughts. Getting it right for your envisaged usage is very important at this stage, as I'm sure you are only too well aware.

[end edit]

1.2 mm is too thin. By the time you realise you have a little rust nodule, it will already have penetrated. After 10-15 years, the 16 ga (1.6 mm) galvanised tub 'insert' is still as good as the day it was installed. Even the tub sides have turned into lace panties at the bottom after 30 years. Jimi welded some 16 ga over these bits. I sealed along the upper edges, then painted them.

The rearrangement of my web albums has had to wait, as backing up my Gallery DB is proving problematic. Wasted a good deal of yesterday afternoon on that!

Stilson,

I have a different view to Ratbag re the 1.2mm Steel. In my experience if you are building it yourself send it off and get it hot dip galvanised. 1.2mm will be plenty thick enough and save a couple of kg over 1.6mm. If you galvanise it you may get away with 0.9mm depending how much framing and bending you use.

To paint it properly you should get it blasted then spray prime, within 2 hours so you effectively have to have it blasted and sprayed and then top coat. By the time you have done all of that the galvanising won't be much more expensive and will give longer lasting protection and get into all the corners that get missed when painting.

Clearly you are going to tour with this thing the paint will be chipped before you even get to the gravel. At lest with hot dip there is some-self healing properties to the galvanising once paint is gone it is rusting.

I camp with a trailer that weights about 500kg loaded I would not take mine of anything but good gravel if there was any sand on the track I would stop as I don't know I would get through coming out of Honeymoon Pool at Wellington dam with it fully loaded on wet gravel track would be interesting. The difference in 500kg and 400kg it is about 0.2l/100km so there is a fair change is resistance difference with the extra weigh. Weight matters do everything you can to reduce it.

I wish I had hot dipped mine while I had it in bits, paint is a constant battle. I has stone chips before I made it home from the workshop in Henderson to South Perth after I rebuilt and painted mine.


Just an alternative view -

Crazydave

Gidday Dave

Not so different, mate ... :iconwink: .

I totally agree about the galvanising vs painting. It is a far more durable finish. Witness the condition of my replacement tub floor after some 12-15 years - still like new. Sometimes it has sat for months full of rubbish, and my trailer has only very rarely been parked under cover during its entire life.

Also agree about weight. However, for all that my trailer is very strong and rigid (the latter keeps the seals where they should be, etc), it still weighs less than 500 Kgs fully loaded, including the 115-120 Kgs of my CT tent and fully floored and enclosed annex.

However, I have to disagree about sacrificing strength for a tiny decrease in weight. Mine is reinforced everywhere and built or rebuilt using very heavy materials for a trailer of its size, weight and GVM. I got a lot of opinions from trailer builders and parts supply companies, and they all said the same thing - for any kind of off-bitumen or off-road use make it stronger than necessary, rather than the minimum strength it needs to be.

Having done exactly that, I have still ended up with a light weight trailer, notwithstanding the 3 mm structural steel and 16 ga sheet all round. Galvanising will probably add around 25-50 Kgs to the weight if done properly, but I would still recommend doing it.

Weight (mass, inertia) really only matters when accelerating. Once cruising, frontal area (drag) is the most important factor. Dragging my trailer with tent and load around the suburbs shoots up my fuel economy badly. However, I know from experience that it doesn't make anywhere near such a difference on the open road.

When towing it empty, I would usually remove the rear gate because it acted like a parachute and made it very hard for my asthmatic Impreza and tiny engined Colt. It also killed the economy for both.

Gidday ST

stilson said:

What is the distance from the front of the drawbar to the McHitch pivot point?

Click to expand...

Sorry for the delay in answering, I have to unlock the security cable to measure this.

It's about 190 mm from the front of the coupling mounting plate welded to the A bar to the centre of the pin receptacle.

The 2,000 Kg McHitch comes in two versions - 3 stud (2 front, 1 rear) and 4 stud. For a new trailer, I would choose the 4 stud version. It is more strongly attached and more rigid. Consider it extra insurance for this most important component.

Ratbag,

I agree regarding strength my trailer is not dissimilar to yours in terms of age and construction -

My point is you don't need thick steel for the panels if you galvanise it. The sheet work is not the source of strength. KG matter in both how far you can go on a tank and where you can go with the power of a subaru. The more weight in the trailer means more weigh in cans of fuel you will need to carry. There will be a balance - I think thinner sheet steel has no downside if you galvanise.

On a side note have you put your trailer on a weighbridge fully loaded? - your quoted weights seem low to me - my trailer with spare wheel (mazda 15"steel) weights just on 200kg + tent, beds, kitchen gear, a couple of 30kg canoes and a push bike for a kid and you have 450+++kg - if you have water, gas bottles, fuel I don't know what the weight will be. I do know that in most cases people underestimate weigh of trailers by a lot eg the father in law was out by 400kg on a 18ft caravan and that was after he put it on a weight loss program where he weighed the stuff he put in - a cumulative underestimate of bathroom scales could not have helped.

Sorry for the semi hijack Stilson I think the consensus is galvanise I have used Hartways in naval base before they did a good job for me.

crazydave said:

Ratbag,

On a side note have you put your trailer on a weighbridge fully loaded? - your quoted weights seem low to me - my trailer with spare wheel (mazda 15"steel) weights just on 200kg + tent, beds, kitchen gear, a couple of 30kg canoes and a push bike for a kid and you have 450+++kg - if you have water, gas bottles, fuel I don't know what the weight will be. I do know that in most cases people underestimate weigh of trailers by a lot eg the father in law was out by 400kg on a 18ft caravan and that was after he put it on a weight loss program where he weighed the stuff he put in - a cumulative underestimate of bathroom scales could not have helped.

Click to expand...

The tare weight with almost all the new stuff, including 215/60 16 steel wheels and tyres x3, trailer lid, toolbox, gas bottle and fuel/water panniers, was 140 Kgs. Weighed at a VicRoads certified weighbridge. The CT tent and annexe have a shipping weight, including packaging, of 113 Kgs. I have allowed about 5-10 Kgs for extra pegs and two extra poles.

Everything else has been weighed on a mechanical bathroom scale that weighs 1.2 Kgs less than our torsion bar digital scales in 79.2 Kgs. This level of inaccuracy (-1.5%) is not going to lead to any great discrepancies.

One needs to add the weight of the gas struts, lid reinforcing, spare wheel pole reinforcing and the weight of the McHitch over the 50 mm ball coupling. The McHitch is roughly twice the weight. The only significant increase is the extra 20x20 lid reinforcing.

When all is finalised (which it now is), I will unload the trailer of all removable items with the exception of the spare wheel and re-weigh. This will give an accurate baseline figure to work from. At $37 to weigh it, it's not something I want to do every week!

BTW, IMHO 0.9 mm is not physically strong enough to withstand normal wear and tear that any trailer gets from both above and below. IMO this gauge will bend and ding far too easily.

1.2 mm is probably adequate for some sheet work. "Adequate" being the operative word.

IMO, the sheet steel work needs to be strong enough to assist the chassis from distorting due to forces in all directions - vertical, lateral and torsional. For this to work it needs to be adequately strongly welded to the chassis members - particularly to the perimeter frame, but also to the ladder frame. IMO, 1.2 mm is too light for these welds to perform adequately. 2.5 mm checker plate is overkill, but 1.6 mm sheet is ideal. Also a good compromise between strength and weight.

On the latter subject, where have you got these weights from, ST?

I downloaded the excel file from here. https://www.atlassteels.com.au/site/pages/product-weight-calculator.php

RB you will enjoy this Im sure!

I've decided to put the planning to one side for now and borrow my friends 6x4 and take my RTT for a camp. I have enough scrap steel stock to make a bolt together frame and have someone help me lift the tent on to it when we set up camp.

IMO its the best way of guaging what I really want out of it.

Thanks for the tip on the galvanising CD, agree re: weight.

Thanks for the Mchitch measurement, I've found them for sale here: https://www.trailerparts.net.au/online_shop

I will up spec one of their trailer kits with Soob hubs, shackle springs, Mchitch and LEDs. The later I will prolly omit and supply my own.

^ Good thinking, mate ... .

You can buy the McHitch direct from the company for about $30 less, including Oz wide postage.

I came across the Atlas Steel calculator. If it's giving the figures you are getting, it seems odd. Since my trailer uses most of these sections, is fully kitted out with wheels and such like luxuries, plus the lid, etc and has been weighed on a VicRoads certified weighbridge, something's wrong somewhere!

The downside to (hot-dip) galvanising is the distortion that results. I've seen really rigid-framed products go in, and come back reminiscent of a propeller. Unless you have the facility to correct this distortion, I'd be cautious\\\\\\\\\apprehensive.

^ I have also heard that, but didn't realise the distortion could be as bad as that .

If I build the whole thing out of patio tube I should be able to straighten it more easily.

I'm honestly considering aluminium. As long as I can insulate it from the steel spring hangers and hitch to avoid electrolysis.

^ Not sure that ordinary drawn aluminium can be made strong enough at any kind of reasonable price.

IMHO far too much is being made about the weight.
I completely agree that one should avoid over-engineering it to a ridiculous degree. I have eye-balled $56,000 worth of unbelievably over-engineered junk.

I have towed my trailer tens of thousands of kilometres behind seriously underpowered cars (Impreza and even more so, our Mitsubishi Colts). Even they managed to tow it perfectly well and easily. With Roo2, I barely even notice the trailer being there, even when fully loaded.

Towing onroad is one thing, any weight that I have to drag up sand dunes is another altogether! Reversing down a sand dune can be difficult, reversing down a sand dune with a trailer even more so. The lighter the trailer is the better chance I have of not needing to reverse, and if I do jackknife will be easier to manhandle down by itself.

I agree about towing up sand dunes, ST. Madness with any trailer/vehicle. Probably why all trailers are banned from the Simpson Desert NP, IIRC.

My strategy will always be to lock down the trailer in (hopefully) some reputable/safe place, then do 'touring' around the area sans trailer. No way am I intending to go sand groping with a trailer as an ornament proclaiming my stupidity to the world at large. I am pretty comfortable towing it anywhere with almost anything other than deep sand, however. Basically any reasonably firm or hard surface is fine in my books.

IME, the N/A EJ-253 has more than sufficient grunt to tow even a 750 kg trailer most sensible places. However simple reason dictates that if you want to plough through knee deep mud for hours at a time, regardless of trailer or no, a Subaru is not the right vehicle to be doing it in ...