Miranda the Expander

[NJV6]

Last winter I was busy working away on a bit of a project, the story starts with the wife. She likes camping but doesn't like the cold. And uncomfortable beds. I bet this is sounding familiar. And I like doing silly things like camping in winter


I like building shit so it seemed obvious. Spurred on my a mates post viewtopic.php?f=18&t=41755 it began.

Trade Me time. This little gem came up for sale. We bought it sight unseen, and drove 1600km return to collect it off the Ferry. This was our first sighting


Once we got off the Ferry, time for a closer look. It is NZ made, a 1979 Liteweight Expander, basically a pop top with solid sides.



On the way home the name came to us, Miranda. Miranda the Expander.
Set up on the Lawn



My wife quickly get set too cleaning it and giving a bit of paint here and there, some pictures of the inside with the squabs out






I took a look underneath and saw a bit of the dreaded rust in the floor... so looked the other way and we then went away for the weekend to the beach



It looked a bit silly behind the wee Paj, and the rust was bothering me so it was time to get the grinder out. 1st take the wheels off, hard job to do with no wheel arches. So I made some




It needed bigger wheels. Of course it needed bigger wheels.
To fit something like this, the floor had to be cut so out came the wheel arch and a bit of the floor



Couldn't get the wheel arch out of the otherside without stripping the entire sides of Miranda so just cut the back of it instead


Drilled out loads of pop rivets to pull the sides away to get at the rusty bits



This is the rust I was talking about


About now I decided to go all out , so I ordered some airbags from the states for suspension and decided the dump duratorques it currently used, it was just going to bob along the road otherwise. So with a heavier duty suspension the chassis was going to need laminated as it is only C section. 7 inches of travel will mean I can level Miranda on a non-flat camp site.


New chassis time





Then I fed the sheep


Lowering the chassis off the caravan


Rolling it out



Hover van

[stealth]

I like where this is going!

[Clint]

Cool! Some friends got one of those a few months back & brought it camping... The boys did a bit of standing around it, beer in hand, discussing how it could be a pretty good starting point for an offroad camper

Cheers
Clint

[NJV6]

Hey Clint.

Yea I liked it as it is hardly any wider than the vehicle, unlike most. It makes it a bit harder for me to sleep in (over 6 foot) though!

[NJV6]

Now it was suspension time for chassis, Airbags need something to hold the axle in place, do I use some very light leaf springs for placement or use some suspension arms, I decided on the latter as it seemed like fun. I got some LandCruiser 80 suspension arms and used them as my lower links. About now I got some suitable wheels and tyres to use, I have some std hilux rims on 205x16's, may go a smaller tyre size or 3 yet, depending on final height.


and made the top link myself using the bushes from the original top landcruiser links




Caravan Flex


Ugly as anything but no one will see it! And it works! the axle sits nicely in place and does not rotate when lifting and lowering so the airbag remains stable. There is a bit of bracing to go on to it yet but I can't see much force going onto the top arm, maybe a little when braking but how effective are brakes going to be on a 800kg caravan anyway??

[NJV6]

So I had the airbags and wanted to get them mounted,
Upper chassis mount


And the lower mount on the axle


I then thought mounting it so far behind the axle may create a bit much leverage than id like. I had made them like that so I could mount them as low as possible and get the chassis to sit right down on the axle when not in motion to aid getting in and out.

Then farming got in the way again and I needed the woolshed for shearing so rolled the old chassis back under and took it for a drive to another shed


Back to it
Cut the old mounts i had just made (duh) in half and mounted airbags



And the the mig ran out of wire Grrr

Then fizzed them to the chassis




I have ordered a new water tank to go right behind the axle, as you can see from screenshot below, you can pretty much get anything you want! I got 47 litre, 2nd from top.


Then I started on the floor of Miranda, the reason all this started! So after lifting her off the chassis (again) I got a new rear sub frame made up then ran out of CO2 in the welder! Grrr
Here it is sticking out the side so I can weld the top of the joins.

[MihiT]

Watching with interest. I've acquired an old ford transit camper (WIDE body) that I need to trailerise as the cab/front of chassis is rusted to hell.
Just wondering, why airbags rather than coils or leafies?

[NJV6]

A few reasons. 1, I can level the camper when not on a flat site which is often, 2, I can lower it to make access easy when parked yet have heaps of clearance when I require, 3, for a very soft and wobbly ride to make sure it handles the bumps and doesn't wreck everything inside. Hope that helps, for me it was the only option.

[mudlva]

Yep i can understand the airbag concept.

But still a bit lost on why so much articulation?
Vehicles require it due to have two axles spaced apart. 1 wheel travels as the other 3 carry load.
On a single axle wouldnt the whole wheel and body just follow the ground contour.
Up travel may be absorbed but down travel not at all??

Just asking

[tweake]

On a single axle wouldnt the whole wheel and body just follow the ground contour.

thats exactly what you do not want. you want the wheels to follow the contour but not the body.
most trailers had such little suspension travel that they just pound the crap out of your load.

[tweake]

looks like thats going to be braked. it would pay to have another suspension rod fitted on the top of the axle to stop the axle turning when under braking. (assuming its beam axle and not independent)
chuck in a set of trailer shocks and it will be sweet.

[mudlva]

On a single axle wouldnt the whole wheel and body just follow the ground contour.

thats exactly what you do not want. you want the wheels to follow the contour but not the body.
most trailers had such little suspension travel that they just pound the crap out of your load.

But thats the question..
How does it articulate when it hasnt got a second axle taking the load as the off loaded wheel travels down into the rut or hole etc.
I can understand the concept of air suspention as it will absorb upwards directed loads.
But on drop off loads the complete trailor will just follow the wheel downwards.
Granted that the will be absorbtion as the wheel strikes the otherside and starts the travel upwards again.
That said i can understand up travel shock absorbtion but cant see how down travel would be of any assistance when crossing holes and ruts etc as wouldnt the the complete unit just drop into it as well??

Only asking.

Thinking of replacing the chassis on my caravan and wanting it to travel better on the gravel roads etc so following this discussion with passionate interest

[mudlva]

looks like thats going to be braked. it would pay to have another suspension rod fitted on the top of the axle to stop the axle turning when under braking. (assuming its beam axle and not independent)
chuck in a set of trailer shocks and it will be sweet.

He has. Its got a"A" arm top link show in photos previous.
Should take any twisting forces and keep it sitting in place quite nicely

[ChurchurDan]

I have been reading a lot of this sort of stuff as I want to build an off road poptop caravan. The general consensus from all the different sites is that a trailer will not articulate as it will rotate on the coupling, this gets worse when you have a trig style coupling that cant rotate freely.
Most of the better (more expensive) aussie offroad campers and trailers use independent with airbags to get the smoothest possible ride when towing over corrugations and rough roads for a long time. If you watch any videos of them being towed over rough terrain the wheels don't move much and the trailer follows the ground contour, which is often in the complete opposite direction of what the tow vehicle is doing.

[tweake]

looks like thats going to be braked. it would pay to have another suspension rod fitted on the top of the axle to stop the axle turning when under braking. (assuming its beam axle and not independent)
chuck in a set of trailer shocks and it will be sweet.

He has. Its got a"A" arm top link show in photos previous.
Should take any twisting forces and keep it sitting in place quite nicely

opps i missed that.
that will work a treat.

tho what about panhard or do you think A arm will be enough for sideways ?

[tweake]

.
But on drop off loads the complete trailor will just follow the wheel downwards.

Thinking of replacing the chassis on my caravan and wanting it to travel better on the gravel roads etc so following this discussion with passionate interest

i don't know exactly how the bags act as a spring. a normal spring will simply push the wheel down due to its preload, but thats also relative to trailer weight.
with load sharing duals the 2nd axle doesn't hold it up, the trailer still drops. how much depends on a few things. with non-load sharing dual axles then it will stay level but also all the load is transferred to that one wheel which is not what you want for quite a few reasons.

to me the whole point of having longer travel is to get better shock absorption and reduce the impact on the trailer itself. its not going to change how it goes through holes etc as such when your going slow enough that the suspension doesn't move. thats going to be down to ground clearances. longer travel can mean higher trailer with more ground clearance.

this is something i'm interested in as we do a fair bit of farm driving with trailers.

[mudlva]

Need to make sure we stay on topic here as NJV6 is doing an awesome report

A arms in buggys work well no reason why it will not work on a trailer set up.

Clearance is all to do with either independant suspension set up or tyre size lifting the axle.

"Ind susp" to me is a lot more complex than what NJV6 is doing altho it will give more clearance than solid im picking thats not been the total aim to his project. Its all to do with upgrading from the little mini biscuits to something a lot more durable for off road traveling.

Imho he will need some form of shock set up as any down travel with the wheel will tear the air bags apart.
Shocks will limit this issue completely

[NJV6]

Cool, got talking going! Mudlva, your last post sums it up. The 'upper arm' of the rear suspension is fine for this application.

This poptop is actually finished and works very well, more than I had hoped for, I just haven't finished the write up!

It does have shocks and I never intended it to have flex, just like good for the pic!

Glen

[ChurchurDan]

Then hurry up we want to see how it turned out
Where did you get your airbags from as I need a set?

[NJV6]

We shot to Wellington for the weekend to see the Military Tattoo so now I can reply properly.

Then hurry up we want to see how it turned out
Where did you get your airbags from as I need a set?

Airbags came from the States and are a Slam Specialities bag, usually used for bouncing cars and I got them from switch suspension as they posted to NZ. 6 inch airbag with something like 7 inches travel with internal bumpstops.

I have been reading a lot of this sort of stuff as I want to build an off road poptop caravan. The general consensus from all the different sites is that a trailer will not articulate as it will rotate on the coupling, this gets worse when you have a trig style coupling that cant rotate freely.
Most of the better (more expensive) aussie offroad campers and trailers use independent with airbags to get the smoothest possible ride when towing over corrugations and rough roads for a long time. If you watch any videos of them being towed over rough terrain the wheels don't move much and the trailer follows the ground contour, which is often in the complete opposite direction of what the tow vehicle is doing.

I thought long and hard about doing an independant setup but in the end figured I am not going hardcore off roading fast, I just wanted something that rode nicely as to not destroy the poptop as it is lightly built and that is why I liked it, it weighs about 800kg with water, gas the lot, yet is solid in the wind and completly dry in the rain. I also figured to do an independant setup I would struggle to get it to track as well without building some camber/toe adjustment into it.

When towing this it does follow the contour as you say yet the suspension still absorbs any holes etc, most unlike most trailer springs!

[NJV6]

So I got busy with the water tank frame, I wanted it removeable to be able to fully drain it for the winter frosts. Here you can see the 1st top link i just made from bits of scrap while I was waiting for steel.



New mudguard frame so I could pop rivet exterior back into place nice and strong


Rear bumper and strengthening (not that it needed it!)




Finally got the Frame painted!


Stub axles welded on, pissed me off a bit as the engineer took 1mm too much off the stubs so they were hard to centre in the axle but hopefully it is close enough. Put the new chassis under the caravan and made up some shock absorber mounts


Mounted shock absorber. In this pic you can also see how much of the floor I cut back to be able to fit larger wheels.


Cut the front of the drawbar off to make a mount for tow hitch


Hitch mount


And here is Miranda sitting under her own weight on 205R16 tyres with about 2 inches of air in the airbags, so it can go lower and another 5 inches higher


HOWEVER
Not content with all this, (and it was still a month until lambing!) it was still eating away at my insides that there was still the rusty floor in the front to deal with as I had planned to do that next winter. But thought what the heck, out with the grinder. 1st a tidy up


Had to strip interior draws at the front and unscrew/drill out/beat out old stuff, what a job! But got there eventually



Lowered chassis away from top (AGAIN!)



Done - happy now, no rust! Reassemble time
New mudguards

[tweake]

looking good

[NJV6]

Side access panel. This houses anything I want to access with the lid down, air compressor for springs, battery & isolating switch, blocks etc




Brakes plumbed, airlines done



Rear stabilisers, obviously the wind down normal type were going to need a 4 inch block of wood to be effective so redesign


This is in its travel position, it sits about 2 inches proud of the roof and is going to be a kayak mount which will run the length of Miranda


Ready for the 1st trip

[NJV6]

Water tank mounted and finished with new filler



Put the 12v switches in



Storage box and gas bottle


Spare wheel mounted

[DieselBoy]

Very cool

When you bringing it up north behind the NJ??

[NJV6]

DB, I'd need a fuel tanker on the back!

[NJV6]

We have been away in Miranda quite a few times now

Works a treat. Perfect for us, only need to grab some food, sleeping bags and pillows, check battery charged and full up water tank.

East Matukituki, Omarama Saddle.




Got some strange looks from others travelling to the top of this pass



Small enough to fit into some cool spots



Anyone been to Lake Mavora mid summer will know how bad the dust on the road is 45km gravel road. Needless to say dust ingress was a problem, it wasn't finished and there was still a few holes not filled in the floor..... a brush & shovel got added to the draws and upholstery now gets turned upside down. Having said that it was much better on the omarama trip with holes filled!


And some inside shots, my wife loves decorating so really enjoyed doing the inside.

[Clint]

Cool!

Best you get a coat of paint on the outside to keep up with the missus's styley work on the interior. I reckon zebra stripes would be awesome

Cheers
Clint

[wjw]

Cool!

Best you get a coat of paint on the outside to keep up with the missus's styley work on the interior. I reckon zebra stripes would be awesome

Cheers
Clint

[NJV6]

Guys Guys, settle down I'll talk to her but I'm not sure about the chances....... The leash is pretty long but that might be pushing it....