Linner Strømlinet Vogn II

[Sven7]

Let me preface by saying I've asked for Leitman's How to Build an Electric Car book for Yule, so hopefully that will answer some questions.

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I've been studying ecomarathon cars in the pursuit of ultimate energy efficiency in a planned electric reverse-trike project. Among a few of the most outrageous prototypes this one stood out. I've been trying to work out a viable package for the driver and equipment, however interior shots are hard to find for these things. Finally, a French-language web page emerged, which I link to you now.

(Google Chrome automatically translates for you)
Les stars du Shell Eco-marathon Europe : Polyjoule et Microjoule - Page 3

The highlights, according to the site:
-Started const. in 1984, unbeaten since 1992.
-Cx of 0.11 (Same as Cd?)
-Weight of 30kg, or 66 lbs.
-8,924 MPG (Yes, nine thousand)
-Apparently fiberglass body shell and carbon fiber wheels.







Now, obviously driving it would literally be a pain in the butt. I would, though, like to adapt some of the technology to road use in a hyper-efficient commuter. A few questions:

Does anyone know what the wheels are made of, what size they are, and what type of tires were used? CRR of those tires?

I would like some up-close shots of the steering linkages and knuckles.

What is the frame made of, and what does it look like?

What's the turning radius?

Frontal area (to calculate CdA)? Seems to be around 0.4 CdA!!!

I plan on using a steering interface not unlike a recumbent bicycle, as it will make ingress and egress much easier (no wheel to climb under). Not sure where to position the batteries. Front suspension would probably be a variation on Ford's Twin I-Beam setup. Simple (primitive), robust. Rear would be custom-built similar to motorcycle rear suspension.

I think I'm on the right track, bodywork wise. The driver's (my) feet should rest just aft of the front axle(s). It should be a reclined, but not extreme, driving position with my back rather close to the rear wheel.

A quick sketch... I'll upload more later, perhaps. Surely I have enough pages filled with this thing


Stomlinet Vogn by Tyler Linner, Intergalactic Man of Mystery, on Flickr

Does anyone know about making custom in-hub electric motors? The ones on e-bicycles only go 45mph. I suspect the higher powered ones might sustain an ecomarathon car at highway speeds, but getting there would be a problem. The goal weight for the vehicle would be around 700lbs with batteries, without rider and cargo (+150lbs). I would need around 25hp to equal the power-to-weight ratio of a diesel Mk1 Golf. That's the performance goal.

Range goal is 100-150mi. Lofty? Maybe. But with Volts and Leafs on the market, perhaps Li-ion batteries will not be so expensive?

Oh, and I don't want to be a dick about this, but can we keep the random image/tangent posting to a minimum in this thread, pretty please?

Okay, discuss.

[Chopper]

Those wheels look like they're carbon fibre to me.

[HypermilerAX]

Yes, wheels are carbon fiber. They are 16 inches mounted with Michelin Radial tires for solar cars. Probably 45/75 R16 with a Crr between 0.001 and 0.002, they are inflatable to 100 PSI.

Frontal area is around 0.3 m², CdA is much lower than 0.4, it's 0.033.

[ballo]

You might do well looking at Australian series racing HPVs. Very custom, but suspension is rare or nonexistant. The interior space created by rollcage requirements makes the basic styles more suited to commuting modification than Eco-marathon shells and chassis
The Phantom team forum seems to be the most active for the past few years, or search for "Pedal-Prix" for general images.

As for tires, the Michelin ecomarathon special radials, I'm not sure if they're available to the general public. Schwalbe currently has Tryker radial tires in commuter and lightweight racing versions available on request, 40-406 (20"x1.5"). The other popular option is Greenspeed Scorcher (40-349) and Duro slick (40-406) which were developed to replace Tioga Comp-pools which changed in design.

Looking closely at the wheels I would expect that they are cut from reinforced carbon panels - Pre-preg layers over a honeycomb core of aluminum or kevlar (Nomex) - with an alloy rim bonded on. An example (from a heavier material) is part way down this page

[kach22i]

Originally Posted by Sven7

Does anyone know about making custom in-hub electric motors? .......I would need around 25hp to equal the power-to-weight ratio of a diesel Mk1 Golf.[/B] That's the performance goal.

I have a bunch of old bookmarks I could go though. I was looking for 100 hp and never found anything. If I have time I'll see what I can turn up, seems like there was more than one at 25 hp, a golf cart thing maybe. It was not cheap, that much I do remember.

The typical cheap pancake motor can peak at 25 hp and sustain 20 hp reliably. I've sort of looked at FWD short axles and CV joints as a way to inboard the motors and keep the sprung weight down.

Commercially produced hub motors which people could slap on a wooden crate and drive off in is a long time fantasy of mine.

EDIT: Inspiration - if they could do it in 1900, why could not we do it in 2012?

The first Hybrid Vehicle
by Dr. Ferdinand Porsche

Jacob Lohner & Co in Vienna, Austria produced electric cars from 1898 to 1906.
Ferdinand Porsche, one of Lohner´s employees developed a drive system based on fitting an electric motor to each front wheel without transmissions (hub mounted).
Vehicles of this type were known as Lohner-Porsches.

[Sven7]

Thanks, everyone. The HPV's look like they're more or less custom bodies over standard recumbent tricycle chassis? I've thought about that... might not be useful enough for the trouble of building one. I'll be making a custom chassis for this car anyway, so maybe it would be more easy to adapt the ecomarathon car after all.

Kach, the golf cart is an interesting idea. I may have to look into that. What kind of life span would those motors have?

Did another sketch yesterday, this time with more effort. Colored pencil with gouache highlights. I like the purple with light blue interior. The fenders are less prominent... good?


Stromlinet Vogn by Tyler Linner, Intergalactic Man of Mystery, on Flickr

One interesting thing is that the Microjoule's fabulous proportions are simply the result of styling over the large rear wheel. I love it, but my limiting factor will be the head room. A longer wheelbase will make it more stable at speed but decrease turning radius. Still have to run calcs on turning radius vs. wheel angle to reverse engineer the max wheelbase, and work from there.

I've been sitting on the floor to measure the space needed. Should be less than a meter tall, and perhaps 3m long like the 'joule. I'd like my feet behind the axle for rudimentary crash safety.

[freebeard]

Now that would be a fitting successor to the Anal Probe. Did that thing ever sell?

[arcosine]

You can buy a fiberglass body if you want to build one. I was looking at these a few years ago, but there is no room for pedalling.

http://destinyparts.com/

[Sven7]

freebeard, I've gotten a few nibbles but nothing serious.

arcosine, part of the appeal of this project is that I get to design and build my own car. So, it's exactly what I want! Looks like a good site, though. The motors go up to 19hp which is just a bit shy of my power goal.

Wow! They've got swing arms and shocks and wheels and brakes and everything! *Bookmark!*

[arcosine]

On at tadpole trike, for best stability, the cg should be near the front, as the rear tire reacts no overturning moment.