I have been investigating many different methods & materials to build the drop down platform. I haven’t decided which way to go yet, but I do know which way other camper manufacturers construct their drop down platforms.
First off, as you’d expect, most of them use aluminium. As far as the construction goes, this is usually an outside box frame with 4 or 5 internal supports, all made from 40mm aluminium box tube. Cover the frame with aluminium sheeting (tread plate or normal) at around 3mm thick, to act as the floor, you then have a sturdy platform to walk on. This seems like the common construction method and if you didn’t want to spend too much time figuring out the various load spans & ratings of other materials, I would recommend going with this approach.However, if you wanted to dig a little deeper into the engineering sides of things, I think there may be some improvements to be made here. According to my rough calculations, a box frame & sheet described as above would weigh around 35kg. That’s not terribly heavy, but if you were planning to manually lower & raise the platform yourself (like I am), plus have a storage box attached to the back, you may start to wonder whether you’ll need assistance from another person just to lower or raise it (not ideal in my opinion!). The box frame and aluminum sheet would both weigh around 15kg+ each. So I’ve looked at alternative flooring materials to compare the weight and performance (e.g. load spans) to that of aluminium sheet. Composite materials are of course available (at a price) but do offer many advantages (i.e. thermal breaks, etc). Some of the sheet/panels I’ve researched had high enough load ratings that you wouldn’t even need as much support underneath, which would save us considerable weight in the box frame itself also.
Here are a few of the flooring panels I’ve come across so far:
- Duflex Panel (foam core, honeycomb, end grain balsa)
- FRP Grating (frp, pultruded grating)
- Grating (aluminium)
- Expanded (aluminium)
- Honeycomb Panel (aluminium, polypropylene)
I’m currently still reviewing viable options & costs for the platform flooring material. If anyone has experience in this area or ideas that could help with the design & construction of this platform, please leave a comment!