YorkshaDave
New member
Hi Folks.
I'm in the process of building a demountable habitation box for the back of an ex military DAF T244. I'm building it in a demountable way as it will offer flexibility for lifting during construction and also maintenance, not for shipping purposes. Box construction will be steel frame, similar I suppose to the Bliss box's.
I did consider using the exisiting vehicle load bed as it's already proven in taking a composite box as per Steve W's truck but rightly or wrongly I've decided to remove it to get rid of all the Tupperware that is attached to it, help reduce overall height and add an extra element of cushioning and torsion relief. I should point out at this point that I do not have plans to travel the world in our truck, whilst that may or may not happen in the future, the project was started as something to keep me occupied during a period of rehabilitation, provide overspill accommodation for guests and also to try and convert my wife to the joys of UK camping without having to subject her to a tent. I'm hoping underfloor heating, a decent bed and a shower should help!
I've spent ages reading about subframes and their relative pro's and cons and spoken to a few vehicle owners and come to the following conclusions for my truck:
3 and 4 point pivoting systems are out due to localised stress loading, road handling and the fact that my truck was designed and built to tackle off-road situations without them.
With that in mind I'm down to 2 possibilities.
Option1) Build a simple ladder type rail on rail sprung system utilising the existing 8 mounting areas on the chassis to locate the spring mounts. I will have to fabricate new mounts as the OE mounts sit slightly outboard of the chassis rails as per the attached pic. The existing mounting points are all located close to chassis crossmembers and I can use the holes in the chassis webs that the current mounts utilise. Construction of this subframe would be box section main rails and cross members with cross rails sat atop. Three sprung mounts down each side, a lateral locator plate at each side at the front and solid mounting plate at the rear. Cushioning between the chassis and subframe would be either HDPE or Balata.
The pro's of this option are simplicity/ ease of construction, strength and the fact that the habitation box mass is distributed evenly along the full length of the chassis rails and well cushioned and it seems to be a well proven method.
Option2) Build a ladder subframe using 100mmx50mmx5mm C section main rails as per the OE bed. The rails would then be attached to the OE mounts which means they would not sit on the chassis rails but be suspended above it as per the OE bed. C Section cross members would sit atop those rails as per the OE bed. se attached pics showing where the OE rails sat against the mounts approx 75mm above the chassis rails. I would add springs to the mounts to allow an element of torsion relief as per option1.
Pro's of this system are that it would be lighter. Cons, it's uncharted territory and the mass of the habitaion box is sat on 8 mounts and not distributed along the chassis.
I'm a grown up, I appreciate this is not an exact science and if there are issues down the line then it's on me but I'm a firm believer in experience trumps theory so would love to hear other folks thoughts if you've had, seen or built similar
I'm in the process of building a demountable habitation box for the back of an ex military DAF T244. I'm building it in a demountable way as it will offer flexibility for lifting during construction and also maintenance, not for shipping purposes. Box construction will be steel frame, similar I suppose to the Bliss box's.
I did consider using the exisiting vehicle load bed as it's already proven in taking a composite box as per Steve W's truck but rightly or wrongly I've decided to remove it to get rid of all the Tupperware that is attached to it, help reduce overall height and add an extra element of cushioning and torsion relief. I should point out at this point that I do not have plans to travel the world in our truck, whilst that may or may not happen in the future, the project was started as something to keep me occupied during a period of rehabilitation, provide overspill accommodation for guests and also to try and convert my wife to the joys of UK camping without having to subject her to a tent. I'm hoping underfloor heating, a decent bed and a shower should help!
I've spent ages reading about subframes and their relative pro's and cons and spoken to a few vehicle owners and come to the following conclusions for my truck:
3 and 4 point pivoting systems are out due to localised stress loading, road handling and the fact that my truck was designed and built to tackle off-road situations without them.
With that in mind I'm down to 2 possibilities.
Option1) Build a simple ladder type rail on rail sprung system utilising the existing 8 mounting areas on the chassis to locate the spring mounts. I will have to fabricate new mounts as the OE mounts sit slightly outboard of the chassis rails as per the attached pic. The existing mounting points are all located close to chassis crossmembers and I can use the holes in the chassis webs that the current mounts utilise. Construction of this subframe would be box section main rails and cross members with cross rails sat atop. Three sprung mounts down each side, a lateral locator plate at each side at the front and solid mounting plate at the rear. Cushioning between the chassis and subframe would be either HDPE or Balata.
The pro's of this option are simplicity/ ease of construction, strength and the fact that the habitation box mass is distributed evenly along the full length of the chassis rails and well cushioned and it seems to be a well proven method.
Option2) Build a ladder subframe using 100mmx50mmx5mm C section main rails as per the OE bed. The rails would then be attached to the OE mounts which means they would not sit on the chassis rails but be suspended above it as per the OE bed. C Section cross members would sit atop those rails as per the OE bed. se attached pics showing where the OE rails sat against the mounts approx 75mm above the chassis rails. I would add springs to the mounts to allow an element of torsion relief as per option1.
Pro's of this system are that it would be lighter. Cons, it's uncharted territory and the mass of the habitaion box is sat on 8 mounts and not distributed along the chassis.
I'm a grown up, I appreciate this is not an exact science and if there are issues down the line then it's on me but I'm a firm believer in experience trumps theory so would love to hear other folks thoughts if you've had, seen or built similar
