I'm also working on the design for an eight seater recumbent protest mobile, since Evan seems to like the idea. I like the idea of something large and fast. Mostly fast, but I don't imagine that this will actually be fast. Still, it should be fun. Evan wants to have a protest vehicle, and also is thinking of doing long rides (like this) without a support vehicle. So having eight riders and real luggage carrying capacity would be one way to get there.
I'm thinking of two people in front, facing forwards. One to manage gear changes (clutch and gear lever(s)), one to steer and brake. The gears will possibly not be simple, but mostly it's the hassle of having to get clutch, gears, steering, brakes all into hand controls that can be used by one rider that bothers me. So I've decided that one person will not be able to ride this beastie alone. Not unreasonable, since the weight is likely to be over 300kg empty. We will also have as much as 2kW of power going through the system, so I'm thinking of a car or motorbike gearbox. The problem is that they usually shift with a clutch, and people don't like sudden changes in load. So if there is a clutch it will have to maintain the loading somehow, by shifting seamlessly to a braked mode. Or perhaps we just need to co-ordinate gear shifts with the riders. That would remove the clutch, saving weight and complexity.
Here are two versions of the seating, and rough idea of how the driver will work. Red for shaft drive, green for chain drive, blue for steering and black for the car. The red lump is the gearbox, possibly. Having a car gearbox will give us reverse, which will be essential.
The simplicity of the transmission when everyone faces inwards is offset by the difficulty of getting in and out, and the lack of a view for the participants. It's also not too safe to have the back of your head exposed like that, either in a collision or simply in a parade. But having people face forward will make the vehicle longer I think. It's more sociable, and the view is better though. Depending on space we may be able to fit a third person up the front. Seating is semi- recumbent, as in the Bike-E and so on to reduce the transition change for people, and make it more rideable without toe clips (8 sets of SPD pedals is expensive, and lots of people still lack SPD shoes).
I think that basing the transmission and possibly steering, suspension and brakes on a 4wd motorbike might save a lot of hassle. That would get us 5 or 6 gears in the box, front wheel drive components with suspension and brakes. Motorbike gear should be able to handle the power, it's only torque that may be a problem. The plan is to give each rider at least 7 gears using a derailleur system, and their own freewheel. We may go to 14 or more gears depending on what range we get out of the gearbox. But the derailleur also steps the shaft speed up, which will help interface to the gearbox (and bring to torque down, reducing shaft sizes). So it may be a case of using the biggest chainrings we can find, and the smallest clusters. Initially probably scrounge bits, and try for old 10 speeds with 50T chainrings.
The hassle will be how much we have to gear it up. Motorbike engines typically rev from 3-8krpm, and cyclists at 60-120rpm. So we need to gear up about 50x to get the same speed as the motorbike crankshaft. With any luck the motorbike will gear down a fair bit into the gearbox, because even at highest we only get about a 4x gear up from derailleur gears. But we can gear up again using industrial chain to go into the gearbox, but possibly we will need to gear down after the output because the motorbike box may not be rated to haul 1Mg of gear up a hill (300kg of vehicle, plus 8x80kg people). But then, you do see those 4wd farm bikes pulling trailers, so who knows. Perhaps we need to get the gear and build a bike to see what happens.
Possibly turn it into bike wheels by simply drilling spoke holes in the motorbike rims, and use larger spoked motorbike rims and tyres to get load carrying capacity. At the back I think non-driven wheels but probably we will want steering. I suspect that steering of the back could be done by the left hand driver, because it will be slow speed stuff only. Just having 20 degrees or so of turn will help a lot in tight spaces. This is the main use of the vehicle, I think - walking protests, a way to carry a lot of banner etc using pedal power. It may be worth building it heavy so we can put a platform on the roof and use it as a float.
We will need lights and indicators etc, so some solar panels and a couple of old car batteries might be needed. The batteries for sure, the panels if we can get them. Running everything on 12V and using 20/50W halogen rally lights as headlights should do the front end, and LED stop lights could perhaps be used as indicators too. Even using six or eight of them wouldn't be too bad at only 3W a pop. We could even have one person powering a generator if required :-)
Possibly get something like Evan's Suziki van to start with and just fill it with cyclists to see how we go. Be heavy, but it should take the weight and torque with no hassles. That does raise the other issue though - where are we going to store it? It will need a car-type garage, and I don't want to pay $50/wk to get one if I can avoid it. Perhaps the Black Rose in Sydney might take it? Hmm. It will be light and low enough that perhaps we can put it on its side somewhere. Rough dimensions at this stage are 2m wide, 5m long and about 1.2m high.
We will need ground clearance though, to be able to go up 20cm curbs even when loaded, so perhaps 30cm unloaded clearance. And FWD will hopefully help get up the curbs, but I think a lot of the time it will be a matter of getting out and lifting it up. I'd like to see a petrol van do that :-)
The major obstacles are getting bits (technical), and finding riders (social). It will cost real money, and I'm not sure how easy it will be to get sponsors for the relevant parts. Getting Shimano on board would solve much of the hassle, as we need 10x bike transmissions, which is pricey no matter who's buying. Since we don't care too much, maybe we can get old stock from someone. Wide range would be nice, as would 10 identical sets, but whatever.
Another question is which way people face. If we make the back more a lounge area with the middle three facing backwards it may be easier to design, but people might not like travelling backwards. If each seat is 600mm wide, that's a bit more space for most people. Perhaps start with a 5 or 6 seater as the first version, then build a bigger one if that works?
This is what took much of the first day in Karajini! I rested, wandered round, but mostly had time out on something enjoyable - thinking about building things.
For light relief I rang Tech Rentals from Tom Price to ask about hiring a computer rather than buying one. For a machine with a film scanner, CD burner and a 17" monitor they wanted $1300/month, or $650/wk. Plus 9% for insurance, 1.5% for stamp duty, and $30 for shipping each way. To give you some idea, I can buy (in Sydney) a basic machine with 128MB RAM for about $900, bring it up to a 17" monitor for $100, add a cheap CD Burner for $400 and a decent film scanner for about $500. So all up to buy it is $2000, but then I could resell it after a couple of weeks for probably $1000. Tech Rentals buy more expensive machines to start with, but the film scanner they offered me is about $500. Not exactly what I wanted. Back in Sydney I'm tossing up buying a cheap machine as above simply to save a bit of hassle. But then I'd have to carry it round and that's hassle by itself.