I built this generator box about 6-7 years ago and had it on a former TT. So, the new TT came into the yard and I extended the bumper using 2 1.4x2 1/4x1/8" angle with 'bed frame cross pieces. Foremost in my mind was 'save weight' but make it strong... Between the 'box' and the TT I put a piece of sheet metal to keep the air/water from blowing up behind the TT. The box had to be pretty far back because of the TT back angle. The 'box' was built for a Boiley inverter generator to be placed in the center compartment. It had good air flow and I piped the exhaust out the rear. I put a door in the side to operate all the controls. It was very economical and 'light' at 75lbs, but the inverter stopped 'inverting' and I bought a Honda 3000si inverter generator..
Now the weight became a factor with the Honda weighing in at 140lbs. The Honda is really a good generator and economical, but there is no 'tailpipe'. So, I had to use one 'side' compartment for the exhaust and duct it through that and out the bottom. I tried to buy 'shock absorbers' insulate the vibration but they were too expensive for the number I needed (livin' in poverty pocket you get creative). I used a 2" hole saw to cut shock rubbers from a 'horse stall' foam pad from Tractor Supply. After cutting a few I decided to cut holes in the pad to place under the generator to save weight. I have yet to put the generator in the box (I used it 2 years with the other TT) since I rebuilt the 'rack' and vibration insulators. That post will come soon...
this compartment is the exhaust
I need to put the cover back on the 'bare wires'...
To explain the construction of the 'box' the bottom is a 'cargo carrier', the top was cut from a Ford Ranger size tool box, the sides were a 4'x8' sheet of aluminum cut to 20" wide and was bent at a friends sheet metal shop, a few pieces of 1/2" in aluminum angle about a 'thousand' pop rivets, some wire screen from C-band satelite dish, some cans of gray primer for the inside, a few cans of brown for the outside color, insulated for sound mostly as the exhaust temp on the 'uninsulated' box is about(measured) 140 degrees. I was going to take out the insulation but it only weighs about 3-4lbs..