[pilferage]

The basic idea is that we use an engine like this and mount it in a very low slung, aerodynamic trike. The engine uses ~190g/hp*h from 2-3.5k rpm, so lets try and figure out what kind of mileage this thing can get assuming we're traveling at 55mph, diesel fuel has a specific weight of 3336g/gal, and the engine uses 190g/hp*h.

(190g/hp*h)((1/3336)gal/g)=.057gal/hp*h, (17.5hp*h/gal)(55m/h)=962hp*m/gal

So, if we use 1hp (I wish) at 55mph, we'll get 962mpg, 2hp is ~481mpg, 3hp ~321mpg, 4hp ~240mpg. So, can we design something for a single ocupant that needs less than or equal to four hp at 55mph?
I think so (thanks to an lj'er in the gearheads community)...

(stolen from lj'er, credit goes to him)
Drag is D=Cd*A*.5pV^2, Cd is the coefficient of drag, A is the frontal area, P is rho (constant, mas o menos), V is velocity. Lets use SI for this and work backwards (so to speak).
55mph=25m/s, 3hp=2235w, so we're looking at ~90N of drag at 55mph.
At sea level p=1.225 kg/m3, let S=Dp/(.5pV^2), then S=.24m^2.

Assuming a Cd of .2, then D(S*Cd)=A, or .24/.2=1.18m^2 of area.
So, if we assume half that to compensate for driveline, cooling, and wheel drag we'll have .6m^2 of frontal area. More if we assume 4hp.

So, about 2.65ftx2.5ft (it'll probably be taller and skinnier). Now, I'm thinking the trike's body would be fiberglass, the frame would probably be off of a 80's cb650 motorcycle, the engine would be mounted up front to counterbalance the rider who would probably need to lean back significantly. The easiest transmission might be some kind of friction sifting setup, with gears attached to the driveshaft, which is directly connected via chain to the drive wheel. I was thinking about using two very strong mtb wheels with solid tires (no blowouts). If they can take 20 foot drops they can take highway driving... maybe.

Anyhoo... I'm looking for suggestions regarding the driveline/wheel combo, and the aerodynamics of the body. Also, don't hesitate to correct any of my calcs... it is 3am after all, who knows what I could've mussed up.

[MD]

Your 55 mph dream is likely just that, a dream. Great exercise though, I am sure you could attain very high mileage.

[WisJim]

Some high schools and colleges participate in a "high mileage vehicle" contest. The vehicles that they build to compete may give you some ideas. They typically use bicycle components, are 3 wheeled (2 in front that steer, one in rear to drive), may use a 2hp B&S engine, and get 200 to 400 mpg on gasoline traveling at 15 to 25 mph.
Some other sites that might help you figure things out have been mentioned here on one of the other PO forums. Look around a bit, and you should find links to human powered vehicles with electrical supplemental power, another good source of info.
Some others of interest:
VWs 1liter car:http://www.canadiandriver.com/articles/gw/vw1litre.htm
using a small diesel to power a Geo Metro:http://www.utterpower.com/10hp_chevy.htm
I think that Googling for high mileage vehicles would find other stuff of interest.
I think it is an area with lots of potential--I want a VW 1 liter car myself. Too bad they decided not to build them.

[Aedo]

Think it is a great idea!!! Couple of thoughts:

$this->bbcode_second_pass_quote('pilferage', 'T')he easiest transmission might be some kind of friction sifting setup, with gears attached to the driveshaft, which is directly connected via chain to the drive wheel.

[Googolplex]

Id be even more interested if it was a true electric hybrid, where the diesel is used solely to generate electicity in a small light and super efficient gas turbine, and the drive wheel has an electric motor directly connected. The drive train and gearbox can be left out completely, and the weight saved with that, plus the weight saved with having the lighter turbine for burning fuel, would leave plenty for the batteries and a charger.

This would not only be even more efficient, but has the added benefit of being able to directly power it off of nearly any liquid fuel (turbines aren't picky) instead of just diesel or just gas, and/or power it off a source of electricity.

[Aedo]

$this->bbcode_second_pass_quote('Googolplex', 'I')d be even more interested if it was a true electric hybrid, where the diesel is used solely to generate electicity in a small light and super efficient gas turbine

[strider3700]

I've been thinking of the diesel electric hybrid for awhile now. Small diesel generators putting out in the 5 kw range are not insanely expensive or anything. Toecutter should jump in and correct me but I think that 4 or 5kw should be enough to push a car down the road at speed if you are careful with the peddle. Size the generator large enough to provide extra electricity and push that into a battery pack to be used for extra power when needed. This way the battery pack doesn't need to be 1/4 to 1/2 the weight of the car and you get the benefits of running off of pure diesel. I'd size the battery pack for 30 km of travel giving me enough power to get too and from work on pure electric and the generator can kick in otherwise.

I'm way too tired to do the math on this to see if it's even feasible tonight though.

[The_Toecutter]

A few members sent me some PMs asking about electric faring covered bikes, and other things. I know it's been a while since they arrived, but I'm still typing up the responses. Between college and the fact that I have no way to finance college(dad incapable of working, scholarships pay most of my tuition but it is a $28k a year school) and took out a loan that's pending using a credit card to pay it in the meantime(When the loan comes, the credit card will be paid.), and the fact that I'm trying to keep up with this hurricane and show people workable solutions to the crisis facing this country(not lilely to be implemented, oilies want a crisis for $$$), I've not had much time to respond.

[gg3]

Second try posting this...

Toecutter and others who are serious about working in this field, see my post on the first page of the "Why not switch to electric cars?" topic, there's news.

In summary: I know a guy who's started a company to produce a high-spec electric vehicle. Has prototype working to specs. Has appropriate capitalization and business infrastructure, as well as engineering capability, new patent applications included. Has jobs available, with real paychecks, contact me for details. This is for-real, no BS, no pie-in-the-sky. When you hear about what he's doing, you'll be more than slightly excited.

Re. DIY diesel trike: (the following is a city-car, and has nothing to do with the high-spec EV above)

The diesel you have there is 211 cc. In the 1950s, Messerschmitt made a 2-seater 2-wheeler using a 200 cc gasoline engine, that got 90 mpg and had a top speed of 65 mph. It can be done again. Google search under "Kabinenroller" for pictures (German for "cabin scooter," i.e. enclosed motor scooter). The Messerschmitt in its original form is a potentially interesting application for a 211 cc diesel.

However I see another interesting application here. Find a good 49 cc diesel. That would enable a 3-wheel 2-seater PHEV that's viable for city driving and would be legal as a moped, i.e. no regulations. Chassis/body components are available from a specialist manufacturer. The PHEV powertrain could be dropped into that platform and it would be something that could be produced on a workshop manufacturing scale.