Trailer Tent for a small car - home build

[St.Jude]

2 hours ago, Bfg said:

Since then I've taught myself other practical skills  ..most usually motivated by my wanting something but not being able to afford to buy it already made, so I've had to make do with whatever I might cobble together.

This, all the day long. I know everyone feels like they can't do it but you can. We all learnt to walk, we all learnt to talk, so nothing is beyond anyone who's willing to learn.

I'm properly impressed with all of this. I hope to study all of it over the weekend to catch up. It's inspiring stuff!

[Mally]

I've mentioned this in my own topic, but I unknowingly copied Pete's Falcon all those years ago.

My effort was very 'Square box' in comparison to his. He may find a photo of his for comparison.

I was also a failed trainee draughtsman. My oily Motor bike fingers damaged the drawings.

[Bfg]

Today's effort  ..started by finishing off the sanding.  It only needed to be of a decent shape, and not scratch-free smooth, because I was yet to fibreglass over it.. and that of course would leave a rough and fibrous surface ..again   ..So coarse grit sandpaper on a 1/4" thick flat (but slightly flexible) board was used for most of that shaping.

^ Fibreglassing over the top of all that shaping ..started off with a thin layer of glass 220mm wide (because that's what materials I had left) over the corners and down the flange.. This was a hot mix (twice the usual amount of catalyst added to the resin) so that the resin would gel quickly, rather than draining away off the vertical flanges.  I show this picture because the first dabs of resin on the glass-fibre does look S..T  ..but bare with it, and roll the bubbles out and in due course it comes out looking OK.  If I could learn how do it as a typically dumb n' spotty 15 year old, I'm sure you could !

This is one I prepared earlier . . .

^ hot mix, cured quickly enough. That was the first layer and I sanded the high spots off that fibreglass (even though the not fully cured resin clogged the sandpaper) in preparation of the overall covering..

^ I'm all but out of glass-fibre mat.  This is the last piece of the thicker (600g/sq.m) I had, so although I'd have preferred it to go to the corners and right to the ends, I made do.  The wrinkles are from it being the end of a roll, and having been too tightly wrapped. It's less than desirable but they will smooth when its wetted out with resin.  

 

Before wetting it out I peeled half the thickness from the first couple of inches, all around the edge. This was to help feathering those edges (prevent such a hard edge).  

Now the work really started.  Although just for two-hours, the top layers had to be done quickly and there's absolutely no break  . .

 

^ That top layer of thicker glass-fibre was applied and then another light-weight layer (250mm wide) applied over the edge of that and down the sides again (more or less aligned with the bottom of the flange).  The different widths between layers were to help minimise hard edges of the fibreglass being evident through the final finish. 

Those layers each had to be carefully laminated with most all the air bubbles removed, which takes a great deal of care when the amount of resin is being kept to the minimum (which is lighter and yet stronger).  And then over this, while still wet, I stretched- a top layer of finely-woven glass.  If the underlying shape is half decent, this fabric gives a much better finish for finishing than the roughness of the chopped strand mat. 

As you can see from the background by the time I finished this evening, it was quarter-to-nine ..and dark. The finishing touches and cleaning of the brush and roller were literally by torch light.

^ a close up detail of one of the corners (sorry not very clear because of the flash photography), and perhaps further confused because of the colours of filler seen through the semi-translucent (still liquid) resin and the glass.  Perhaps you can make out the fine texture of the woven cloth in the reflections..  

Using glass-cloth has a great advantage, in-so-much as it can be pulled taught across the flat expanses and over the corners, and like stockings over less attractive legs and knobbly knees, that stretch is ultimately flatter and smoother than what's held to shape underneath, especially when that might be hairy ! (glass-fibres) 

That's all for tonight, but tomorrow I'll try to take clearer piccies.

Bidding you a good evening,

Pete. 

 

[Bfg]

 

On 8/6/2021 at 11:41 PM, Bfg said:

Perhaps you can make out the fine texture of the woven cloth in the reflections..  

Using glass-cloth has a great advantage, in-so-much as it can be pulled taught across the flat expanses and over the corners, and like stockings over less attractive legs and knobbly knees, that stretch is ultimately flatter and smoother than what's held to shape underneath, especially when that might be hairy ! (glass-fibres) 

That's all for tonight, but tomorrow I'll try to take clearer piccies.

as promised,  clearer pictures . . .

   

^ some small air bubbles on a corner or two, where the resin was squeezed out as I pulled the fabric / woven glass down.  That's not a big deal but I'll see if a little fresh resin will rub into them.   The cloth's texture is very apparent, but when compared with the lumpy and fibrous finish of chopped strand mat - it's brilliant

^ different reflectiveness, of where there's slightly more resin (wet) in places, makes it look patchy - but the final shape is now defined. As expected the (0.5mm high ?) step, of the edges of the grp layer applied to wrap over the sides, is apparent ..but all-in-all it'll now not be too daunting a task to skim a little body filler over this lid and to fair it smooth enough ..for a box trailer mostly made from scrap !

Does anyone have experience of body wrapping on vehicles.? I'm thinking of having this lid covered ..if that finish is then durable enough to sit outside in all weathers, and of course is cost effective.? 

Thanks, Pete

p.s. it keeps peeing with rain today, so I'll take the day off manual work and draw up a cutting list for the (revised yet again) chassis instead.  In the meantime the fibreglass resin (which is still a bit tacky) will have a another day or two to harden. That will be evident by a slight change in colour from the bluish hues to more like Autoshite beige.  

[Bfg]

Just a little more progress today ..aside from a major clear-out of the back of my Chrysler (it's been a shed for fibreglass materials and bits of wood, tools & fastenings, etc).. And otherwise inbetween rain showers, telephone calls and very nice people stopping by for a chat . . .

^ Mostly 40 x 2mm shs (square hollow section) for the camping trailer's chassis. But some 25 x 1.5mm shs too (which is all I had otherwise I would have used more of that to save weight).  Also, still in the postal wrapping, is 1190mm (odd length to me but that what was being sold on ebay) of 35 x2mm shs. This will be used inside the 40x40 as its telescopic leg.

^ First six parts tack welded together, using the bigger off-cut piece of 3/4" plywood as a set square and flat surface, as I tacked it together ..because the paving slabs are not at all flat.   As an indication of scale, those paving slabs are 24" square, so this frame / this trailer isn't very big.

^ The 'outriggers' are all welded up and attached to the central spine, and I've just tacked the axle cross-beam in.  I'm pleased to say it's all surprisingly flat and I've managed to avoid twist ..by tacking before welding.   As said, I would have preferred to use lighter-weight steel for the outriggers but that would have meant my spending even more money.. and for what ? ..to save a couple of kilogram in weight.

As it is this weighs 10 kg, so it'll be close to 15kg, when it's done, plus 30kg for the wheels n' suspension and a towing hitch. I also have in the back of my mind - to have the camping box removal, to be replaced with a crude 3/4" plywood open box, for box-trailer-to-the-dump duties. And this chassis is plenty strong enough for that purpose.!

Rain stopped play again, and so after just a few hours.. I called it a day.  Still it's nice to be getting close to putting wheels on the chariot. 

Pete.

[catsinthewelder]

Wouldn't be a bad idea to make it removable if it's not too much trouble.  If it's getting more use you'll have less issue with things seizing up and it gives you more chance of finding indoor storage for it.  What about a way to carry a motorbike too?

[Bfg]

^ too short for a motorcycle ..well one of mine anyway, as it's only 4ft long, but yes the more useful it is ..in whatever guise the better it would be for the chassis. 

 

Today's update :

Starting off with.,  cleaning up the new suspension units ..so that I can get bolts through the holes !

   

^ galvanising part filling some of the holes had to be drilled out, and the blobs on the top face ground away so that bolts and their washers would sit flat.

^ the time consuming part was how to hold the suspension unit and wheel in place, square to the trailer and upright, and of course the right position fore & aft and sideways.. all the made more difficult because I wanted the chassis / trailer low and so the suspension unit both sits on top of the chassis (inside the box, and is mounted at an angle (about 54 degrees according to my drawing..   With the chassis set square to a spirit level, 18mm plywood packing was used between the tyre and the chassis rail for the width, and to keep it (tracking) aligned to the chassis rail.  An 11mm was used under the suspension arm for height and to set the angle. and then the tyre sits on another block and is wedged there to stand upright (again to the spirit level).  

Then I measured the angle with an adjustable set square (a woodworking tool) and transferred that to two posts which are to sit under the pre-drilled mounting plate (kindly supplied in the kit of suspension unit, hubs, wheels, bolts and even a pot of grease). As seen in this photo the two posts are just loosely positioned (not even tack welded in place). 

   

                       "two wheels on my wagon..,  and I'm just rolling along"    or summit like that ! ?

Tacked in place and free standing. the balance is a just little to the tail end,  which is good at this stage and why I fitted suspension units behind the axle.   You can see that the (leading) arms are almost square to the ground (actually just slightly tilted down a few degrees) and that's because this trailer is intended to be 100-120kg unladen, perhaps 150-170 kg loaded  ..and when horizontal the suspension will be more responsive  In other words.. if the suspension units were at 45 degrees, as quite commonly installed, they would have an effectively shorter lever arm ..and so the suspension would be stiffer. That's not good for this the trailer, because it's too light (and will never be laden to their 350kg capacity).  I'm 110kg (yeah I know ! ) and with me standing on the central-cross-bar the suspension arms are only just about level to the horizontal (it they rotated just a few degrees.

And then the suspension units came off again, so that I could finish welding those posts in  . . .

   

^ posts welded in and the suspension mounting are securely fixed. This photo shows the chassis inverted as I added another little plate (3mm thick so in tension it would carry over 10 tonne !) which is a brace against the upward twisting forces of the suspension.   The cross beam itself is presently only tacked in place, because I expect to have to move it (..forward a bit) after I trial fit the body - so that I get the nose weight (on the towing-hitch) I'd like. 

The box with its lid is slightly heavier (partly because of using recycled materials, but also because of the flattening-out issues I had with the lid), and then - I've also altered the trailer's design by turning the body around ..and moving the split line / door, oh, and also the hinging of the lid, oh yeah and I've . . . .     ...Nothing too radical then Pete ! ? 

Back to work.. next, I moved to the front end of the chassis to make the swan neck, from the low chassis bed up to the height of the towing hitch . . .

    

^ the bottom corner of the swan-neck is the most stressed part of the whole chassis, and because it will sit tight to the trailer's body - there's no room for a triangular (gusset) plate.  So I'm using hidden reinforcing within.  This little box-section angle is made from 35x35x2 tube and naturally fits inside the corner. Once fitted inside, the outside box section (40x40x2mm) corner is deliberately left a little open, so that the weld penetrates and therefore also joins this inside support.  

^ the outside corner was also ground away to expose the inside support and then I welded up the corner.  You'll also note a couple more welds 45mm down the edge.  I used an angle grinder to cut through the outside box sections and into the inside support angle ..and then plug-welded those holes up again.  That securely ties the inside support to the outside chassis members in four more places.  I reckon you'd need a 40T press to break this corner open !!   ..but once the weld is cleaned up, it will be a neat and compact structure.

Next.. the telescopic extension . . .

   

^ first though some more ground holes in the corners ! ?    second photo showing a length of 35x35x2 inserted into the chassis tube ready to be plug welded in place.  six either side using full penetration welding.. to neatly join one tube to the next. 

^ The previous welding was by the right hand clamp, and again with the chassis inverted the swan neck is seen down-turned. The clamps are simply holding another temporary length of box-section-tube flat to the sides of the central spine ..to keep that straight and true, as the first front outrigger with body mount is positioned and welded into place.

So there we have it ..  and the chassis is finally taking shape . . .

^ the telescopic leg (yes I changed the originall design which had two, to now just have one telescopic tube ..which is plenty strong enough for towing, and I hope  will also work well enough for deploying the telescopic camping trailer.  Only testing will prove the design A-OK ..or else crappy !

All up chassis weight so far is 15.5kg.

Btw., the head of the swan neck is not determined yet because I don't know the height of the ball hitch on the car ..and I've not made the towing bracket yet.   Nor do I have the car (Triumph sports car if you recall) back yet from having its chassis swapped, so that detail and the towing hitch will just have to wait.

in the meantime . . .

^ back to having two wheels on my.. chariot.?   Each paving slab being 24" sq provides a dimensional scale, but although I've not added stops or locks yet - the telescopic extension is 700mm. The trailer's chassis isn't designed to be towed when extended, this is just for when the camper is open.  Drop down support legs will prevent the central tube from bending and twisting when I clamber around inside ! 

^ contracted, the telescopic part will be pinned for towing.  As you can see the present nose weight (without towing hitch or body) is being measured. . .

^ outrageously heavy at 1lb (1/2 kg).  I' pleased with that. 

That's it for today..  I hope to loosely drop the body tub on tomorrow, so that I can assess and perhaps adjust for nose weight. 

Hope this thread is still interesting for y'all to follow. 

Pete.

[Bfg]

a Quick update  before supper..

^ Transferring the designed footprint of the tyre onto the underside of the body tub..  measure and pencil mark,  stand back, check.  Measure again before cutting.  It's like doing rounded-off mental arithmetic in your head to see if thing are in the right ball-park.  At some time or another, we all make mistakes (..well perhaps not you ! ).  In this particular case I started off from measuring from the wrong end of the body tub !     But, having stood back to check before cutting  (..to see an overview rather than the detail) I caught the error. So, no harm done ..but for an extra pencil line  

^ cut to as small a, tyre profile, size as might work

Body tub sitting on the chassis for the first time, albeit on blocks 98mm higher than it will be (to sit over the suspension arms) and no wheel-arch clearance between the tyres and their holes.

^ lid on before I checked the balance (nose weight)  . . .

^ in the right ball park ...which is encouraging

With the weight of body and lid on, the suspension has moved a couple of degrees. the bottom edge of the arm was set up to be parallel with the chassis rail.  That degree of movement is just fine. 

The body is resting on 4 blocks, and so I need to mark the floor to then cut it so that the suspension also goes inside the body tub. This is all part of my wanting to keep the trailer low down, both for seeing out of the sports-car's rear view mirror and also to keep its centre-of-gravity low down.

* marked and cut, adjusted a few times for clearance and ready to drop back onto the chassis again .. this time without the blocks to hold it up.

Anyone remembering the original design, might recall that the narrow width of the body was to the front.  As I said in my last post, I've now turned the body around so the widest part is forward of the wheels and, like the car itself, the trailer tapers to be narrower at the back. 

^ top as it was originally, below with the trailer body reversed.  The axle moved and the track has also narrowed because I was keen to keep the angle between the towing hitch and the tyre patch much the same. my target was less than 23-degrees to centre-line.  Originally I had 22.4 degrees and the reversed body is 22.8 degrees, so not quite as good as it was, but I don't think such a small difference will be noticeable either in tracking or when reversing.       

Anyway back to the build . . .

^ that works.  Naturally there will be inner mudguards and a low-level boxing-in over the suspension units to thereafter keep the inside of the box dry of road spray.   The load space behind the wheel's axle line / balance axis (..which is in this case further forward than the suspension arm's axis) is still ample to balance the loaded trailer's nose-weight. 

^ looking very low ground clearance, in fact it's 115mm (4-1/2") and the bottom edge is yet to be trimmed off.  The top corner of the lid is presently 745mm (29-3/8") but the lid is sitting low on the body at the moment. The target height was to be less-than-800mm ..which is just a little lower than my cars rear wing line, and so I'm on line to achieve that.

So there we are, the body is now sitting down and in the right place on its chassis frame.

Pete 

[dean36014]

Great work, going to look very retro and match the triumph well. What are the plans for the living accommodation?

[Bfg]

^ a bean bag and to curl up like a big softy dog..    no ? 

Oh, I thought that would be easiest and probably most comfortable too. 

In which case, back to plan A..  which was a camping bed with a 1-1/2" thick mattress on it  + camping cooker and the basic essentials for camping rather than caravaning.

I've reviewed the canopy, numerous times now, and generally keep coming back to very similar to what I started with in the first post of this topic, aside from it being a little taller for headroom as I go in and out.   That compromise between "spacious" accommodation and a neat little camping trailer is something I'm still trying to improve.

I was looking at it again today, and also the trailer's nose weight (which is critical to a good handling trailer).  I discovered * ; if I move the axle by 20mm it makes 19g difference to the nose weight, so even if I moved it 100mm the nose weight would only be a kilogram different ..I decided to leave it where it is.  Naturally this had to be finalised before I cut the wheel arches and make the inner arches.   

Pete.   

 

Edit ;  

*  Oops. Time to 'fess up ..   I miscalculated, insomuch as what I wrote above is correct when changing of the lever-arm-length to the ball hitch, and again for adding / subtracting other weights ..but only for the existing balance condition.  And that condition changes when the axle is moved.  I'll look at this again, because my estimation (..thinking in bed last night) is that if I move the axle forward by 20mm then the weight on the towing hitch should be almost 5kg less.  And, in anticipation of what else is yet to be built-in and also how the load spaces are likely to be used - I'd rather like to have 5kg less on the scales right now.

Still, the reason the axle beams are only tacked in place at this stage is so that I can easily change its position.  My subconscious must be smarter than my conscious mind

Pete

 

[Bfg]

Ok, this camping-trailer's concept and the accommodation is essentially unchanged, but pretty much everything else has evolved . . .

 

 

          ^ The three elevations (profile, plan, and end view) on the right  are what I showed at the beginning of this thread, with the narrower end of the body facing forward, and the suspension units with trailing arm are in front of the axle.  When deployed for camping - the grp lid is opened with a three-sided canopy attached. The tail end of the trailer is pulled / extends out by 750mm, to give ample length to stretch out as I sleep. The extension is facilitated by the chassis-frame having two telescopic legs.  Rear steadying legs are dropped to  

Mostly good, but the two telescopic chassis legs would be a nuisance, insomuch as they are where I want to put my feet down beside the bed. There was lack of load space behind the axle to adjust towing nose weight, and the headroom was a little too claustrophobic.   

          ^ The views on the left   are the latest design evolution, now with the wider end of the body facing forward, and the suspension is configured as leading arm (..those heavy suspension units now sit behind the axle for better weight distribution).  Hitched to the car when deployed for camping - the grp lid is opened (with a three-sided canopy attached) and the forward / outboard steadying legs are dropped. Then the main body of the trailer is rolled (its weight on its own wheels) to extend the overall length. This gives ample length for me to stretch out when I sleep.  The chassis-frame now has a single / central spine telescopic leg, and the camping-trailer's doors have moved to the near the front.

Improvements..  just one telescopic chassis leg is less of a nuisance when entering, leaving the camper.  2. Very likely just one will be a smoother action than two telescopic tubes. 3. There is now a little better storage / load space behind the axle , should I need to balance the nose-weight.  4. The top of the hood (fabric) is shorter which should be better / less sag in the rain. 5.  the headroom, above where I'll be sitting to cook) is noticeably better.  6. The doorway(s) are taller ..and perhaps with their being further forward are somehow more logical.. as they are closer to the car and its boot.

I had originally just drawn an arbitrary towing hitch, and this was revised ..when I got around to measuring their height on other cars. The swan-neck structure of the chassis was revised so that the body tub might easily lift off ..so the chassis might otherwise be used for other duties ie., for taking 'stuff' to the skip.  The new swan-neck runs vertically up the front for additional high up attachment to the body tub.

- - -

Moving on  and hopefully another step closer . . .

        The most recent design evolution achieves something I wanted, but previously couldn't figure out how to make work  ...and that is for the lid to hinge from the short part of the body tub, like this (below left)  . . . 

        

^ The new (left) is with the trailer's lid now hinged from the front (towing-hitch end) of the short body section, versus (right) the lid being hinged from the back / longer body tub.  I've shown the manikin in the same place relative to the cooking station, but with the lid opened to just a little steeper angle - the interior volume suddenly appears somehow much bigger.

Hinging the grp lid from the short part of the body tub, positions it closer to the door way, which in turn sets the tent's maximum headroom where I most need it.. over the doors. The canopy's door zip is a smoother curve and 10" shorter, which will be more convenient and less saggy. 

Sitting to cook, facing forward under the grp lid, has good headroom and the tent canopy over the bed can now be lower = less wind buffeting and steeper angles for rain water to run off.  As a bonus the hood frame, which supports the lower / bed end of the enclosure is a much smaller (tube) loop.

It seems intuitive to pull up and where possible to park the car facing into the wind.  I'm thinking this lid configuration might also be easier to deploy.  ie. open the lid (possibly on gas rams ?) and place the props to hold it up. Then, pull the chassis pin and roll the main body backwards on its own wheels. The rear hood stay is automatically pulled up to the right angle.  Lock the telescopic chassis tube (fit the pin) and press stud the cover around the trailer.  Job done, tent is pitched.. put the kettle on. 

However.., up until now, I just couldn't figure out, when hinging the lid off the short section, how to keep the stays (props holding the grp lid up) from not being in the way of the doors.  Surely they either need to be sufficiently angled or strong enough mountings to be solid against gusty winds .?   But now, I think, I've devised a workable solution...  What if the stays (one on either side) of the lid are not skinny props from the body, but instead are sturdy 'door posts' ..able to withstand bending loads ? 

As drawn, these door-posts also serve as the steadying legs for the front of the trailer. Because they go to the ground ..as strong winds buffet the lid - the stays are braced against the ground, like compression posts. The door posts would be latched just inside the trailer sides. As shown in this illustration, the door posts are just 1300mm long, and a couple of those would neatly fit inside the closed box for transit. 

I had previously tried (in design drawings) to use braces taken back to the trailer's main body, but rejected the layout because those props would have been in the way of the doors.  I think the vertical door posts will work if they are strong enough not to bend backwards. 

I'll sleep on it tonight and have a fresh look at the drawing again tomorrow ..but I'm encouraged by what I see.

Bidding you a good evening,

Pete.

 

[barefoot]

The Dormabile roof on my bay is supported on each side by two tubes running one inside the other & a little ball that pops out when it's fully extended. It feels strong enough to withstand some pretty high winds and it's much bigger & heavier than yours. Here's a crap picture.

 

[Bfg]

Sunday..

Saturday this weekend was cancelled, and so on Sunday afternoon I did a little two step.. two steps back to move one step forwards . . .

^ Body off, suspension units off, cut the cross beam's tack welds and remove the mount,  put the suspension unit back onto the mount, level the chassis on blocks, realign the wheel to the chassis some 21mm further forward and 5mm lower, re-tack in place before welding solid.  Repeat on t'other side.

or in other words..  move the axle forward a little, so that the body tub's centre-of-gravity is further back and closer to the axle's axis. 

Reason ? ..to lessen the nose weight just a little.   

Consequence ?  ..not as much as I had hoped for..  in fact just 1-3/4 to 2 kg off the towing-hitch nose weight.

Anyway., the decision was made and I now need to move forward with this trailer. 

Btw., the 5mm drop in suspension unit height was just to improve the ground clearance a little.  My design was for 5" ground clearance, but I forgot to allow for the trailer's weight settling on the suspension  ..oops    It's now back to 4-3/4"  ...so not too far off.

- - -

While the chassis was exposed, I also added some body mounts. . .

^ same 40x40x2 box section cut off at 45 degrees.  The block & clamps are only there to hold it in place (level with the top of the chassis) while I tack it in place.

Monday..

^ Today I added some inside-corner gusset-plate body-mounts down the central spine, (again using off-cuts of steel I happened to have), and then also drilled the brackets to take 6mm bolts.

        

^ sod it..  I just realised that I often shuffle a trailer around by lifting its tail across ..so at some time I'll add another pair at the back corner of the central spine

 

Anyway, now with the body dropped back in place . .

  

^ with the simulated towing hitch (a piece of wood clamped square to the swan neck) loaded with the hitch and jockey wheel (roughly in place ! ) and measured 316mm (as per my design) from the body to an edge on the scales.. the nose weight is now about 12-1/2 kg.  That's better than the 15kg it was nudging to before I  moved the axle forward.

Next, I'll drill the body mounting holes through the plywood, and then, with that position firmly defined, I can mark to cut the wheel arches  

..about time too !

Pete

 

[mintwth]

Just a thought but don't you need a steadying leg or 2 of some kind at the rear of the trailer to stop the trailer pivoting around the axle's axis and lifting the hitch/jockey wheel off the ground when you're camping in the trailer? If the grp lid is hinged at the front, then any wind blowing on it will tend to tip the back end of the trailer down.

As you now seem to be sleeping with your feet towards the hitch, any steadying legs on the back wouldn't get in the way any more.

 

A leg or two at the back could also be useful if/when you want to change out the camping box for an open top/tip run box . The jockey wheel/being hitched can keep the front end up but unless you leave the trailer hitched to a vehicle there's nothing to stop the back end from tipping down when you're loading/unloading stuff into/out of the trailer.

[Bfg]

^ Thanks mintwth..  

Tbh I cannot say for certain. 

With the axle moved forward from the original design I had thought about the camping trailer's stability when opened up  ..This was in terms of where my own body weight might be centred + whatever is loaded into the back end of the trailer.  And I had wondered about the trailer 'sailing away' with me chasing after it   ..if parked with only the jockey wheel down (three wheeler, no brakes ..and no steering wheel !),  but I'd not thought about the wind tipping it over end over.   Definitely worth considering. . . 

 

       

^ so, looking at the drawing ;  there looks to be a 45 degree angle between where the props fasten to the lid (the point of reaction against the wind force) and the footprint of the tyre (which if chocked is the tripping point).  And the lid itself is at a 54 degree angle ..so like a car windscreen, the winds will mostly flow over & around it. As with any tent, or caravan, I'll have to accept that buffeting will be felt in strong gusty winds.  

I don't yet know where the centre-of-gravity will be ..when the trailer is extended out, but if I were to consider just the 15kg towing-hitch nose-weight plus the 20kg weight of the lid, hinged and so pushing down on the front edge of the body tub   ..it is the same as having it on the end of a 1500mm lever arm (to the rotational axis).  The wind force would have to apply a horizontal force of 41kg against the props fastenings (1267mm above the ground) to tilt / to counter the trailer's extended-forward centre of gravity.  Disregarding the 54 degree angle of the lid and the rounded corners of the body tub and lid, the frontal area of the trailer and opened lid is 1.93 sq m. And so an average of 21 kg per sq.m wind-force. This equates to 58mph winds.

if you want a more accurate figure then < this > calculation may help.   

I've seen many sailing dinghies lifted away and smashed by the wind (that is aside from those capsizes on the water), and there are roundabouts on the A1 in Bedfordshire (near where I once lived) which are infamous for the number of trucks and caravans turned over by the wind, so I respect its power.  I think for the time being I'll just have to suck it and see how stable this trailer is in normal blustery conditions, and for the time being concede that that this trailer is not to be uncoupled from the car and opened up, in wide open spaces, if the wind is gusting more than say 30mph.

And of course I can always use temporary blocks / bricks under the tail end of the trailer if I haven't fitted rear legs.

Pete.

[barefoot]

Or you could screw in a ground anchor and ratchet strap the towing hitch to it.

Fifteen quid fron eBay, my dog goes no-where without he asks me first!

[Bfg]

^  I like that, as it's a brake too   ..which if screwed down in the extended section might distract some mischievous / fun loving friends taking me for a ride !

[Bfg]

This afternoon's tasks ..

and then.., sharp intake of breath before . . .

^ with both sides cut, giving me the marks to work from - I marked the underside floor,  and cut it . . .

^ turned back upright I need to cut the seat-level board, but of course I couldn't get in from the side with the jig saw..  Wanting a neat cut I started it by hand, using a hacksaw blade drawn along a steel edge.  It's a bit like digging a hole out of prison with a teaspoon (..or so I imagine !) as it's not quick ..but it does work, in this case very neatly.   Once I could get a blade in.. I went back to using electrical power . . .

 

..this interesting moment, was totally undramatic, because it was supported all around on blocks. 

^ for the camera please ..smile 

oh, OK then . . .

 

^ back on the chassis, with corner bolts holding it in place.  The chassis is extended out by 700mm to give 2020mm interior length x 1100mm width. 

 

^ and shortened again.

^ showing how the seat edge will be supported and the front of the storage space under it closed in.  I'd like the front flap to hinge down (perhaps in two halves) for quick n' easy access to the storage space within, as there will usually be cushions and bedding on top. 

^ the working end..  Together with a small camping stove and plastic bowl, this end shelf is sufficiently deep to work well enough as a galley worktop / built-in table.  The lower floor is to be fitted with a deep fiddle ..so as to create a useful storage rack, which I'll probably fit out with plastic bins for everyday upper-kitchen-cupboard essentials like chocolate biscuits, tea, coffee, etc.  ..and otherwise breakfast and lunch things. ie., generally lightweight and most often used stuff.   Most of the counter top will have to be cleared at night because it'll also be the support for the end of the bed. 

So there you are.. the design concept looking as if it might actually happen !   ..and might sorta work too ! !

That's it for today, but the big cut  was made ..and it turned out OK.  The usable space within this little / one man camping trailer is now clearly defined.  It's not a huge camper ..but then it's also not that much smaller than the back of my Chrysler Voyager ..which I have used and enjoyed for camping. 

Tomorrow I'm off to see what the good folk in Wolverhampton have done to my TRiumph..  

So, more on this trailer on Friday  ..I hope.

Bidding you a very good evening.

Pete.  

 

[808 Estate]

It would be worthwhile getting some thin stainless sheeting to line the kitchen end with. Easy to keep clean and heat/fire resistant. Might also reflect some heat back inside if its truly crap weather.

[barefoot]

When we visited the bakelite museum they had a tiny caravan.

It's like every other pod caravan except; if you look closely, there's a panel that drops down from the floor onto the grass, it's protected by bellows, but it provides more foot room. I don't think it's brilliant, but you could appropriate the idea, and expand upon it. For fair weather camping you might have a removable panel - that doubles up as a table!

[Bfg]

Almost September already.. must summer go so soon ?  ..

Since I last posted, some 11 days ago I've been mostly too lazy to get on with the job, but also suffering from back ..and front pains, still some steps forward have and are happening. .

^ The additional body mount tabs have been added in the middle of the back rail (to help the strain when I lift and slid the back end of the trailer around), and then as you can see I've painted the frame with POR-15.

^ while the suspension was off - I greased the bearings and adjusted them for final assembly.

After the paint had dried and all was reassembled again, I thought it about time to make a final decision on the towing hitch length. This was an important dimension because, within reason.. the longer the lever (towing hitch length) - the lighter the weight on the ball hitch (the calculation is the same as for Torque = force x distance ..but here we might substitute the term with ;  nose weight = trailer's weight imbalance x distance from the axle's axis to the ball socket on the hitch).  That's a useful one to remember if you have a trailer or caravan that's always been too nose heavy  ..just extend the towing hitch length (strongly !) to lighten it. 

I had at one time used 400mm as the dimension from body tub to ball,  but when looking at what little was required to achieve a 45-degree trailer to car (jack-knife) angle, I brought it down to 316mm (for trailer compactness). This then was then the dimension I've been using in my drawings ..and indeed for when I measured the trailer's nose-weight using the bathroom scales. The last was recorded at 12-1/2kg (..subsequent to my moving the axle forward 21mm) and although the design objective was an arbitrary 15kg ..when I actually felt it - I realised that was still pretty heavy.  Since then I've been systematically trying to bring it down. In final pursuit of this.. I've chosen to increase that tow-hitch length, just a little, from 316 to 350mm. It's a balance of compromises between nose weight (lever length) and overall trailer compactness.   

    

^ having cut a piece of tube to length, and drilled it for the towing hitch bracket, I decided to add a couple of compression posts, to prevent the tube from being crushed in when I bolted the hitch in place.  I happened to have some 6mm dia. galvanised steel rod ..not so long ago plucked from the skip, and so with a couple of through holes these were positioned and plug welded in place.

 

^ with the plug welding linished flat, I next added a 45-deg diagonal brace, of the 1" box section (bed frame) tube I had left over.  As you can see, some welds are not as neat as others but overall it's strong enough (..and then some some) for the loads it'll be asked to take. The tail end of this diagonal was then marked with a set square, and cut to fit flat against the chassis's swan neck. 

^ although I drawn it up in Autocad with a bolted bracket, I decided to position and weld it in place using the 420mm height of the towing hitch on my Chrysler to position it.  I just hope it'll also be suitable for the Triumph ..otherwise I'll have to chop it off again to move it.  For the time being I just wanted to get on with the job, with least amount of work and in the neatest way.   Btw., the diagonal brace is to double-up as an attachment loop for a towing safety-wire strop.

   

^ welded up, assembled ..and back on the scales again .. now reading 11kg nose weight.  I'm now happy with that.  So, to recall - extending the towing hitch length by just 34mm has reduced the nose weight by 1-1/2kg.  And it also gave a little more length for the jockey-wheel's bracket. 

As you can see the jockey wheel is close to the body, and so has to be dropped before it can swivel around.  This again it was a design compromise ..this time between compactness and easiest convenience. My personal criteria is for a compact trailer-tent, and that inconvenience is small in the bigger picture of camping !   Again the 2ft paving slabs give you a reference scale.

^ although only 3'-6" wide by 4'-6" it still looks big. Perhaps that's in part because many other box trailers are said to be of a similar dimension but their figures exclude the width of wheels and mudguards, or else the body is sitting over those ?    Nevertheless it is what it is. I cannot change that size now !

 

^ although the trailer will have lights and a number plate, it's reassuring to know that the tow-vehicle's lights will also be clearly seen. Of course the trailer cannot be seen in any of the rear-view mirrors so I'll have to arrange to fit flag poles in each corner of its lid. 

Next up will be..  hinging the lid..

Pete

[Bfg]

Hinging the lid.. easy huh !?  .. You just try holding something of this size and weighing 20 kg in the air with one hand while you fit the screws and tiny little nuts with the other. 

hey ho, needs what may. . .

^ recycled stainless steel hinges from a boat hatch.  Positioned drilled and attached to the body tub on both sides.  then the fun began . . .

^ Thankfully the gazebo / car port I'd put up has a central beam, of a convenient height, which I could loop a rope over.  And then with a clamp and block of wood attached.. the trailer's lid could be suspend in mid air.  The trailer itself was of course easy to roll into position under that.

^ pre-drilled by positioning the lid, closed and in place, and then drilling the screw holes through the hinge, the lid and the body.  All I had to do was to fit the screws and their little nuts  ..another one of those 2 minute jobs that takes half an hour !  

^ now hinged on both sides.  Inside the tub you'll note two lengths of timber, which I'd cut to length for stays. . .

^ stay's clamped in place, the lid is now uncoupled from the overhead, and is hinged and free standing.

Evening draws the proceedings to an end. 

 

..until morning at least . . .

^ The lid props double up as legs to the ground, for those corners of the trailer, and nicely steadies everything up.  I'm pleased with how solid it feels, even without brakes on the trailer's three wheels.

With a piece of string, diagonal to the trailer's back corner, to indicate the canvas enclosure (albeit without a hood stay or tent poles at the rear) I then had a fair indication as to the space I'd created (from mostly reclaimed timber ) ..and also the door opening. The question was..  would I fit in ? 

The tape measure indicates a height of 1700mm, and the telescopic extension (..and therefore the door width, up to thigh-height) is 700mm. Yep even I can get through that without issue (and it's certainly very much easier than the crawl-space opening of my last tent).  Step in and sit down, onto a seat which is 470mm above the paving slabs. That too is good for me.  There's no step, sill nor footwell intrusion until the central telescopic-rail, and that's low enough to easily step over.   I'm pleased. 

^ From the seat, the shelves are self evident in their adaptability to be used as a camping galley. 

^ with off-cuts of 1/2" plywood laid down to simulate a berth, I now had a true indication of how the dimensions on a drawing converted to practical reality. . .

^ a little over 2m in length accommodates my 6'-5" well enough  ..and I won't be wearing my size 12 's in bed

 

^ "whose been sleeping in my bed ?"  ..Santa Claus goes camping ?

^ with the bed still in place ; the remaining footwell isn't huge, but I think just about sufficient for the essentials of getting dressed and shoes on ..at least until part of the bed is folded away.  

So there we have it.. the envelope defined in 3d.  The cardboard on the outside represents a fabric lower door, that is likely to be fitted with press-studs.  Again the diagonal strings are just to indicate the hood enclosure and door opening.  

Out of interest (..or perhaps not) the ball-hitch nose weight with the lid up (but legs off the ground) is 21kg.

Next to be addressed were the wheel arches . . .

Pete

 

[Bfg]

Cutting the wheel arches. .

Although I quite like the look of the enclosed sides, the wheels cannot be removed should I get a puncture.  Although wheel spats would reclaim its style ..to do them neatly would take a whole lot more work, so for the time being I've just cut out the shape..   As a touch of retro art-deco style,  I'm keeping the cut tight and also not having vertical ends to the cutouts.  Instead they're basic geometry of a part circle.  Of course if I then don't like the look,  I'll then have the option to cut more away.  

^ marking out

^ cut

^ and dusted off

Next was to add a little shape to the rear corners, in line with what I had on my drawings . . .

^ back corner marked and being cut

^ and so we now have the first-cut of the back corner shape.   The chassis box section is exposed when seen from a low down point of view, but as hoped it fades into the shadows even when sitting on a bench 8ft away. 

I think its looking more like a trailer now, rather than a hot tub ..so first impressions are favourable.  Before it looked as if the back end of the trailer would ground over every hump or speed bump but now, although the ramp-angle hasn't actually changed, it looks more sensible.  Whether the back panel will need to be trimmed straight.. remains to be seen.  Of course the lid's shape and adding rear lights will make more difference, as perhaps to a lesser extent will be similar trimming off of the bottom of the front corners.   In the end there won't be many straight edges to the outside shape of this trailer.

That's it for now.  I bid you a pleasant bank holiday weekend.

Pete 

 

[Surface Rust]

I saw this for sale and immediately thought of this thread:

https://www.ebay.co.uk/itm/Vintage-Classic-Folding-Camper-Dethleffs-1959-/284463499897?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=710-127635-2958-0

Not quite as petite as your design though, and it probably weighs a lot more than it looks!

[Landy Mann]

Just read through the thread, great build and really well thought out

 

 

[Minimad5]

Some brilliant skills on display here !

Would it be worth adding a gas strut or two, to the lid ? 

[anonymous user]

On 8/21/2021 at 8:30 AM, barefoot said:

When we visited the bakelite museum they had a tiny caravan.

It's like every other pod caravan except; if you look closely, there's a panel that drops down from the floor onto the grass, it's protected by bellows, but it provides more foot room. I don't think it's brilliant, but you could appropriate the idea, and expand upon it. For fair weather camping you might have a removable panel - that doubles up as a table!

The dropping floor was also a feature in the 1950s Berkeley Caravette.

This one was owned by a friend, the original owner had toured the continent with it. Subsequent to my friend's ownership it spent a period as a dog kennel at the local hawking centre and then after another owner ended up with someone else that I know.

[Crackers]

This is a really enjoyable read! Lots of nice engineering and design touches in here, clearly a lot of thought going into it. Top work, looking forward to more! 

[fraser.innes.3]

I love the thought that is going into this.


Sent from my EML-L29 using Tapatalk

[Sir Chocolate Teapot]

This is a fantastic build, looking forward to the "in use" review asap.