rad progress

After over-thinking the whole radiator / cooling design, I'm back to what I started with last Fall. Back then, the design was simple: hang a radiator (TDI Jetta rad w/ AC condenser removed) below the belly of the bus at a slight angle. Build a cowling around it to help guide air up into the fins. To better control the temps, have a thermo-switch / manual override in parallel so the water temp would fire up the fans or I could switch it on from the driver's seat if the sensor failed.

I passed that design around to a few people, and I got lots of feedback. First, there was concern that debris could get into the cowling and damage the radiator. Of course, there was a "security mesh" at the opening, but little things could get through. Then there was concern about paper, rags, whatever blocking the opening. What if you hit something and the cowling/rad get smashed? Could you make it so the radiator angle could be cable-driven, so the angle could be changed from the driver seat? Will enough air get in there? Will it really go up through the rad and not around the cowling? Etc. I started working through a much more involved plan, but, in the end, its just too much. I'm back to the original, simple design.

Straight cowl around a rad hanging 5" below the belly of the bus with a manual fan-speed switch.

In the end, that design should work. The folks in Australia hang a rad under their buses at 0* angle, drive them around their deserts, and have no problems. They have big monster fans on theirs, obviously, but I think the stock fans with some angle into the airflow will work.

From Plan to Progress
I got a bunch of galvanized steel from the HVAC section of Home Despot. There were 4 reasons for this. 1 - my welding abilities are nearly nil. 2 - I wanted the cowling to be as light as can be. 3 - galvanized steel is already rust treated. 4 - its strong enough for a first cut (maybe as the permanent). I cut the 2 angled sides from galvanized sheet and started drilling and metal screwing it (m8 sheet metal screws) together. Remember, a triangle is much stronger than a square/rectangle, so if you think about doing a similar thing, think in terms of triangles, not squares. I have the 2 angled sides framed and sided. I have the pieces cut for the rear and front bottom pieces and the top front. I may not have a top rear; it may be strong enough without it, and any bar across the top-rear would interrupt the exhaust air flow. Anyway, I'll be screwing the rest of it together this week (if I don't have to work one of these nights).
I was also able to get the radiator test-hung from the under-belly of the bus as a test fit. While it didn't stay there very long, it gave me an opportunity to test the measurements and chalk in where I'll need to cut the belly pan to make room for the water lines.

Next: finish the cowling. Then, re-fit the rad in position to confirm cut marks. Make belly pan cuts. Hang the radiator, mount cowling, route water lines. Hopefully, I can be that far along before the middle of February.