I don't want to hijack my own thread, if this discussion carries on maybe we should start an <Impact protection> thread--I must admit it's an interesting subject.
Better yet is that a side inpact bar incorporated into the roll bar could be run down the side in the pod and not even show.
Show us a sketch, Dale, I'm not getting it.
I agree with you re structural foam and the temp changes it would experience in the exhaust-side pod.
jamnz6, there's a diminishing returns thing goin' on there for sure, but trading off <some> weight for <some> side protection may be worth doing. Nothing we can do will protect the driver from a Hummer hitting the left side of the car at 30mph, unless we're willing to change the personality of the car significantly. That's not a dealbreaker to me; the same is true of every bike on the road. But a standard Locost is probably not survivable if the Hummer t-bones it at 15mph either--I think a Hummer is high enough and heavy enough it'll get in the cockpit with you at 15. But at 5mph, there's a good chance a side impact from a Hummer (or Suburban or the neighbor kid's Toyota Tundra with the lift kit) would merely push you into the passenger and terrify you.
Point is, someplace between 5 and 15mph, it would be good to have pontoons. "Almost nothing" is, after all, something.
BTW, the pontoons in steel weigh a smidgen less than 15 pounds per as is.
Locost builder and adventurer, and owner/operator of http://www.kineticvehicles.com