Building My Home Made Caravan by JR

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Re: Building My Home Made Caravan by JR

Post by petern1 » Tue Aug 07, 2012 1:45 pm

That is a very professional job and the van looks like it
has been made by a big name manufacturer
PB Challenger
Cormal Excel 511

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Re: Building My Home Made Caravan by JR

Post by muzz_on_line » Tue Aug 07, 2012 8:03 pm

Well done John,

You have absolutely blown me away with your workmanship, and attention to details.

You think so far ahead when you are doing things. I can tell this is just not from experience, but from an ability to thoroughly think through everything. I know you have back tracked a few things, but your analysis of every requirement is astounding.

I salute you for an excellent job so well done and documented.

You set the bar, now it is Bussy's turn to set it higher.
Muzz and Colette

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Re: Building My Home Made Caravan by JR

Post by awill4x4 » Wed Aug 08, 2012 12:20 am

John, how happy have you been with the SugarGlider suspension on you van?
My "on road" 17' single axle Galaxy poptop has just been retrofitted with the SugarGlider suspension and I am due to pick it up from Neville Withers this Saturday.
I've gone for coils and single Koni shocks at the moment but Neville has set it up so I can use 2 shocks per wheel if I feel I need to go that way.
A friend has also retrofitted the same suspension to his 14' Goldstream Explorer and is very happy with the results so I thought I'd ask you if you are still happy going down the SugarGlider path.
I looked at the Vehicle components system and the Control Rider from G&S but I thought that the SugarGlider is more robust than any other available.
Regards Andrew.

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Re: Building My Home Made Caravan by JR

Post by J.REEVES » Wed Aug 08, 2012 9:24 am

Thank you everyone, I hope you enjoyed the thread.

Muzz & Collete,
A lot of use have been caravanning a long time you also may be in that category and have learnt a few things from mistakes and that is a big advantage when building a van so not that smart at times just tried to eliminate the short falls I have experienced over the years.
Yes Buzzy is going to another level well more than one level.

I am very satisfied with the Sugar Glider suspension and Neville was so helpful, I hope he is going OK as he was not well last time I spoke to his company (2 years ago).
I was moving down the Control Rider path to start with because you had the ability to remove the entire suspension in one piece but at the time G&S was not interested in selling the suspension only and was not interested in upping the load rating.

G&S is a copy of Whithers Sugar Glider or that is the way it appeared. At the time I found a van with the Control Rider fitted so I got under it and measured everything, exactly the same dimensions as the standard Sugar Glider.
I said to Neville you know that G&S has a suspension almost the same and he replied yes that is my first generation design the one you are getting is a better design. I asked about patent rights and Neville just said I never bothered with that kind of thing.

I used two shocks simply because of my vans weight, the air bag also needs a lot of control and the location of the shock is such with the air bag that it loses a lot of mechanical advantage but is well protected. As you are doing I would try one shock first and best to get the adjustable type if you can. Can’t go wrong with Koni.

By using coils you eliminate all the extra auxiliaries required to support the air bag requirements also save money. The coils would have to be a much more long lasting option.
I have just sent a letter to Firestone questioning the life expectancy of an air bag but from some internet sites I would think 5 to10 years is it. At $400 plus each an expensive replacement cost.
As I have said before a soft controlled suspension is better on those bad roads and helps save the entire van from fatigue and coils should do the job.

Anyway the Sugar Glider has been faultless for me and the ride is superb and the ability to level the van on an uneven camp site is a very big positive that was not considered at the time when fitting.


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Re: Building My Home Made Caravan by JR

Post by awill4x4 » Wed Aug 08, 2012 11:44 pm

Thanks for your detailed reply John.
I'm really looking forward to picking it up this Saturday so I can continue fitting the water tanks and drop down legs so at least I can use the van.
On the way home I'll drop by a friends place where we will re weigh the van so we have an accurate idea of what the weight difference is going from a solid 50mm square axle with slipper springs versus the new SugarGlider suspension.
Regards Andrew.

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Re: Building My Home Made Caravan by JR

Post by darrens » Wed Aug 15, 2012 4:17 pm

Fantastic job. That applies to both the van build and this thread. Very inspirational.

You talked about working out axle locations etc (and having to calculate moments). Can that data also provide a weight breakdown? I'm keen to see exactly where all the mass has ended up (chassis, body, furniture, appliances, miscellaneous plumbing etc).



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Re: Building My Home Made Caravan by JR

Post by J.REEVES » Wed Aug 15, 2012 10:03 pm

Hi Darren,
Yes the data can give a weight breakdown but would need to look at each item one by one to see where the weight is.

Every item was weighed and its centre of gravity was measured in relation to the left and right wheel and the tow ball coupling. This meant I did a moment calculation on every item from one side of the van to the other and a second calc from the front to rear. The total of all these calculations was simple for XL.
Using Microsoft XL made the entire process very easy to do calculations as I could move the wheel location forward or back by changing one value and all 300 plus inputs would immediately update for the new wheel position.

Example: the wheels at their final location gave a tow ball weight of 275Kgs if the wheels are moved 50mm forward the tow ball weight changed to a 184Kgs, note this is for this van.

Another example of how the 29.5Kg awning affects your weight on each wheel and the tow ball.
29.5Kg awning weight distribution: Tow ball =2.65Kgs LH wheel=32.92Kgs RH wheel = -6.07Kgs
Note how we end up with the LH wheel having more weight on it than the actual awning weight and the RH wheel is actually losing weight, this is because the awning is mounted outside the LH wheel centre.

My 46Kg fridge is mounted 1.439mtrs behind the centre (my reference point) of the van floor area and is 0.121mtrs in from the RH wheel centre.
Tow ball = -6.69Kgs LH wheel = 6.32Kgs RH wheel = 46.37Kgs

Some items that had a large effect on tow ball weight.
90Kgs load in Front Boot = +58Kgs
42Kgs two gas bottles full = +33Kgs
50Kg Front Bed mattress = +25.7Kgs
28Kg Draw bar = +21kgs
35Kg rear air con condenser = -13.5Kgs
36.5Kg rear spare tyre = -18Kgs
24kg rear shower glass screen = -7.7Kgs

Walls and chassis almost balance out it is items that are getting towards the back or front that have the biggest effect as you would expect anyway.
The LHS wall frame was 33Kgs and the RHS was 31Kgs, this was one weight that I was out in my calc by about 30% as trying to estimate the weight of miranti timber is difficult as one length of miranti can be half the weight of another length. Even though my weight was out the centre of gravity was close to centre so had very little effect on the tow ball.

Is that explanation as clear as mud.


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Re: Building My Home Made Caravan by JR

Post by darrens » Thu Aug 16, 2012 9:27 am

Thanks for that. Makes sense.

Your CoG must be very near the axle line for 50mm to make such a large difference in towball weight. I'm guessing it's about 150mm.

Did you do any moment of inertia calculations (sum(weight x radius^2), where radius is measured relative to centre of rotation - probably between axles I think). That's one variable that is interesting in terms of the vans overall stability. That, in conjunction with position of the CoG relative to that same radius point can tell a lot about the relative characteristics of a layout.

The other thing I gathered (which is what I was hoping to tease out), is that if you are aiming for a low weight van, the choice of what goes into it is very important. I was concerned about fridges and stoves etc, but hadn't really considered that the choices of things like shower doors, mattresses etc all can add a few hundred Kg quickly. Then you have to beef up the chassis to match (when the chassis is the primary structural member supporting the weight).

What I'm hoping to achieve is a very lightweight shell, that is structurally not dependent on a chassis for its load carrying ability (the shell replaces the chassis, and the chassis is just reduced to the A-Frame and the attachment points of the suspension), just like a boat hull - exactly like a boat hull in fact, with it's trailer permanently attached. To do that, I'm obviously going to have to be careful about minimizing any parasitic weight increases by choosing light alternatives if they exist. By Parasitic, I mean things that need to be there, but can take away from carrying stuff (like food and water - the GVM vs tare stuff)). It should be just as tough as the heavier build, but only if I keep the weight down.

Thanks again for the response, and an excellent insight into the construction process.



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Re: Building My Home Made Caravan by JR

Post by J.REEVES » Thu Aug 16, 2012 7:53 pm

Hi again Darren,
The example I gave on axle location was wrong, wrong, wrong!

Example: the wheels at their final location gave a tow ball weight of 275Kgs if the wheels are moved 50mm forward the tow ball weight changed to a 184Kgs, note this is for this van.

For some reason I entered a change of 200mm instead of 50mm. So moving the axle 50mm forward changed the tow ball weight from 275Kgs to 253Kgs not 184Kgs.

No I did not do any inertia calculations probably stretching my ability to do so, just tried to keep as many heavy items towards the centre but that is not always that practical so went for a heavy tow ball of about 10 to 12%.

I must say that the van is extremely stable behind the Landcruiser. I did get some body sway (not tail sway) on my first test run but that was eliminated with one adjustment of the shock absorber settings.

The van floor is 5.4mts long so the centre is 2.7mtrs from front or back, the actual centre of gravity is 200mm back from the floor centre. I have set the wheels 760mm back from the floor centre to obtain 275Kg ball weight.

The mattress weight is not the normal as we fitted a latex/wood mattress which is much heavier than a normal mattress.

Sounds like you are using a chassis like the old Airolite or known as an AlKo chassis, could be an interesting project.

If you are interested, the following is a list of items and weights, I have extracted it from the XL file so may look a bit messy, the very last number on each line is the weight in Kgs. Some of the weights were generated from calcs so have a few decimal points.

Bed frame and drawer frame 25
LG bed side tops 5.743008
Bed Mattress 1960x1370x250 49
Bed Mattress Platform 17.8
Bedhead 7.1

Arch 4.3

Under bed contents 20
Front cupboard & draws 12
Front cupboard & draws/cont 20
Front boot content LHS 62
Front boot content RHS 28.4
Air compressor and receiver 14.7
TV Arial 3
Front Top Cupboard 5.5
Front Top Cupboard content 6

Gas Bottle brackets approx 2kgs 2
Draw bar 100x50x3 27.8124
Front main cross rail 100x50x3 15.1404
Draw Bar strengtheners 8.4kgs x 2 16.8
Draw Bar extension down chase rail 5.0184
Draw Bar extension attach plate 4.71
Towing coupling plate 12mm 7.19688
Safety Chain & D-Shackle 4.5
Draw Bar extend to chase attach plate 4.71
LHF Outer support 100x50x2 5.1975
RHF outer support 100x50x2 3.465
Font inner cross beams 100x50x2 12.33
Front Support stringers 50x25x2 13.22895
Front support stringer 50 x 3 flat bar 3.05599
Front Support jack 5.5Kgs 2off 500 to 740 11
Gas Bottle support 100x50x2 3.8241
Door step plate 2x0.43m2 6.912
Steps & mount frame 13
welding wire 28

Drawbar items
Stone gaurd approx weight 6kgs 6
Tow coupling 6
Jockey Wheel in boot See cell A68
Gas bottle LH 12
Gas Bottle content 9
Gas bottle RH 12
Gas Bottle content 9
Body Frame
Wood frame LHS 24.16565 33.2
Wood frame RHS 19.70183 30.6
Wood frame Ceiling 45.1945 25.1
Wood frame Ceiling Front 7.6
Wood frame Front Top 5.1
Wood frame Front bottom 13.85082 4.5
Wood frame Rear 16.2032 13.7
Wood frame WC wall 5.5104 11.5

Wall & ceiling interior ply & aquatile
LHS wall (not bathroom) 9.0216 8.8
RHS wall 11.256 11.2
Ceiling 17.9424 17
Ceiling Front 3.8
Front top wall 6.132 2.4
Front bottom wall 2.3
WC wall kitchen side 5.712
WC wall bathroom side 2.7552
Rear wall 4.536 1.1
Shower front wall (ceramilite) 5.92704
Shower rear wall (ceramilite) 5.92704
Shower side wall (ceramilite) 5.92704

Ply floor
Floor ply = 12.361m2 76.449425

Aluminium clading
LHS cladded area 11.4816
RHS cladded area 15.1008
Rear Cladding 7.6128
Front Cladding 6.006
Roof cladding 11
Alum cover on front curve 1.2
Alum Cover on top front curve 1.2

Aluminium Edge seal 7.2

Radio 1.5
TV 1.5
Battery see A309
Battery charger 2
Control Panel 5
Solar Cell 120Watt 11.9
Lights and power points 15

Compressor & Receiver see A69

Windows, Doors & Vents
Front Window 4.4064 3.8
Front Window protect cover (remington) 2.8
Front LHS 380x762 (double 1)3.098016 4.5
Mid LHS 656x1175 5.52195 4.7
Front RHS 380x914 (double 1)3.579552 7
Front RHS 550x914 Double 2) 4.44492
Kitchen RHS 3
Rear RHS (toilet) 1.787256 1.4
Main Door 15.1

Porch Light & assist bar 3
Boot door LHS 5
Boot Door RHS 5
Battery Door LHS 3
Front Skylight 11
Kitchen Ceiling skylight thermo fan assisted 5

Floor covering carpet 7.7
Floor covering Vinyl 11.5874234

Cupboard Door & Draw fronts (12mm vinyl covered)
Kitchen RHS Top doors swing up 4.41286272
Kitchen LHS Top doors swing up 3.36218112
Kitchen RHS draws (4 off) 3.4724352
Kitchen RHS draw under fridge 1.02865032
Bed Side doors (2 off) 6.00010944
Bed Side draws (2 off) 1.18864128
Under Bed draws (2 off) 2.50760544
Kitchen RHS Cupboard doors (pantry) 1.43557632
Kitchen RHS Cupboard doors (under sink) 1.76456256
Kitchen RHS Cupboard doors (under stove) 2.55497136
Bathroom Vanity doors (2 off) 4.45506048
Bathroom cupboard 3.28602624

Glue Screws Nails and Staples 58.96
Piping & Valves 28

Calculations for weights behind caravan centre point 'C Note: when T = negative towball will lift

1st Water tank 5.5kgs 5.5
1st Water tank contents 82ltrs water 82
2nd Water tank 5.5kgs 5.5
2nd Water tank contents 82ltrs water 82
Grey water tank 10.7
Grey water tank contents 5

Air Conditioner
AC Air handler 5
AC Condenser 35

Cupboard frame 10
Vanity LG tops 2.0408544
Vanity LG splash back 2.70135
Vanity LG splash back sides 1.39725
Bathroom sink 8
bathroom contents 15
Toilet 6
Toilet 10Lts wast 10
Bathroom vent fans 2off 8
Shower base 15
Shower screen 24
Bathroom door including track 11
Mirror 3.3
Water Pump 2off 1.5Kgs ea 3
Accumulator 0.5
Vanity tap 1
Shower tap & nozzel 2
Hot water tank 14.2
Hot water tank door 1.7
Hot water tank contents 22.6

Stove 13
Stove exhaust hood 5

Kitchen table stand & base 29.3
Microwave 12
LG bench top 6.1
LG bench top Splash back rear 4.68234
LG bench top Splash back side 1.692225
12mm Ply beside fridge 7.8
12mm Ply at front end of kitchen 7.1536736
Pantry steel roll out frame 4.8
Kitchen sink 5
RHS Kitchen 4 draw set 12.2
RHS Kitchen frame

RHS kitchen cupboards/cont 30
RHS Fridge cupboard 10.628

RHS top cupboard less doors 6.5447
RHS top cupboards/cont 15

LHS top cupboard less doors 5.55123
LHS top cupboard /con 15
Air con cupboard 3.58445

LHS side seat cushion & frame 15
LHS back seat cushion & frame 15

Fridge 46
Fridge content 23Kgs on 23/08/2009 28

Main Chase rails 2off 66.9636
Main Rail strengtheners 4off 25.415
Rear main cross rail 100x50x2 10.323
LHR rear outer support 100x50x2 3.465
LHR outer support 100x50x2 3.465
RHR outer supports 100x50x2 3.465
RHR rear outer support 100x50x2 1.7325
Rear Inner cross beams 100x50x2 6.165
Air bag mounting plate 6.36792
Air bag & diagonal support beam 6.129
Diagonal supports 6.341
Diagonal support strengthener plates 3.69264
Air bag to chase support beam 9.24
Shocks support beam 100x50x3 8.91
Rear support stringers 50x25x2 19.29195
Rear support stringer 50 x 3 flat bar 3.27204
Chase suspension strength plates 6mm 35.796
Suspension Mounting beam 100x50x6 17.688
Sock absorber mounting brackets 4off 6
Rear Support jack 5.5Kgs 2off 500 to 740 11

Bumper Parts
Bumper 10.53
Bumper bracket to tyre 2.3808
Bumper tyre mount round plate bracket 5.1975
Bumper support brackets 100x50x2 5.805
Plates on chase & supports 1.65
Rear skid plates 2off 2.6
Mud Guards 7Kgs each 14
1st water tank shield and brackets 15
2nd water tank shield and brackets 15
Rear Grey Water Tank shield 12.5

Suspension, Tyres & Rims
{A} Spare Tyre under front 36.5Kgs
{B} Spare Tyre at rear on bumper 36.5Kgs 36.5
Sugar Glider suspension brakes and hubs 143
Wheels two off 36.5Kgs ea (tyre & rim) 73
Shocks 4off 8.8
Air Bags 2off 6

Battery 120AH 28.4
Battery Mount/slide 4.5
Awning LHS 29.5

Roof insulation Tontine TSB 5 8
Walls insulation polysyrene 8.3

Paint approx 8lts 5

Diesel Heater Tank 8.8
Diesel Fuel 15
Diesel Heater 6


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