Originally Posted by Flying Squirrel
Can you provide a link online to bolster this statement ?
Happy to help, Flying Squirrel. The 20% assumes that the majority of particulates are caused by diesel emissions which oxidation catalysts are designed to remove (Tier 4 / Euro 4 emission requirements). In practice this figure will be lower, although there is a general drive towards lower particulate emissions from all engines. It is still cause for concern.
BBC Horizon: Global Dimming
SlowRotor,
I came to the same conclusion about fuel cells and hydrogen, which is why i chose not to further my studies at that time (agreed about the safety of hydrogen too). Eventually the chemistry will allow direct conversion of hydrocarbons to electrical power, then they will "take off". Methanol fuel cells use copper as a catalyst, and i even have my own concept for heavier HCs (but this isn't really the time or place to expand on that).
Regarding Ultracapacitors, they were pinoeered by Toyota (from memory) to expand the performance of their hybrid vehicles. Toyota have played around with some clever hybrid shunt transmissions for many years. Honda chose to stick with LiMH for their hybrids, and for my money offer a better solution.
The real constraint to your guy's project is going to be keeping the cost of batteries and motor down. For this reason alone you are better sticking with LiMH technology, since it is an already mature technology. You will need to get an arrangement of cells that deliver the best power/weight, by keeping cell resistance at least as low as motor resistance. Don't forget to allow cooling of the cells, since they will get warm on take-off power. Once airborn the guy can just thermal, and in fact weight is actually an advantage on a strong thermic day (faster average speeds).
Mart