[Darxus]

Update 2012-06-15

Project page, with all the pictures: http://www.eternalmachinery.com/ecar/

I recommend starting at the last page of this thread to see if anything interesting has been going on.

Riding motorcycles made me realize how unnecessarily cumbersome cars are. But cars have a couple nice advantages, like keeping the rain off. I'd like to build some kind of minimal vehicle with two seats that I could commute in - 35.2 miles each way, and they recently put in charging stations at work. Minimal frontal surface area, weight, drag. I've done a lot of inconsistent babbling about different possibilities here. I have basically no relevant experience, so this would involve a lot of learning. My goals are unreasonable. People with far more reasonable goals give up all the time, so I recognize it's entirely possible I'll never build anything. Most recently I've been thinking something simpler and easier yet still extreme might be good (this thing is tiny):



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Update 2011-03-16


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Range goal: 100 miles (70 mile commute round trip + headroom).
Aluminum monocoque body, TIG welded by me (I've never welded).
NetGain Impulse 9 motor.
12 6v Trojan T-105s = 10 kWh, in pontoons.
Rear wheel drive.
Even weight distribution per tire.
Motorcycle rear end.
Custom double wishbone front end with push rod actuated inboard coilovers and sway bar.
Front center of rotation about 2" below ground (single rear = ground level rotation center).
Clearance: 6" (high, for aerodynamics).

http://www.eternalmachinery.com/ecar/

Original post:
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Motorcycles made me realize how incredibly unnecessarily cumbersome most cars are.

Height: 89 centimeters (35 inches).
Length: ~4.3 meters (14 feet).
Width: ~2 meters (6.5 feet).

Seating capacity: 2.

Based on this kit:
http://evolveelectrics.com/72%20Volt...cle%20Kit.html

22 Thunder Sky 90 amp lithium cells (yellow) (very interested in suggestions).





Not shown is the vertical sheet of metal running most of the length of the car on both sides for structural support. Same concept as the Lotus 25 (first F1 monocoque).

I am very interested in suggestions. I'm far from solidifying anything. Except maybe the seating position and wheel layout. It might be possible to talk me into a tube frame.


My commute is about 30 miles. I want a range of about 100. I actually got a poll at work including asking if I'm interested in ability to charge my car, but of course not counting on that happening.

I need to read up more on the watt hours and ranges of existing vehicles.

Motors generally are listed with maximum volts or something. And that seems to be based on some often unmentioned amount of amps. So am I right in thinking the actual maximum ratings of motors are more related to watts (which I realize is volts x amps)?

I was thinking four wheels, then realized / remembered how much less gearing is involved with one rear wheel. I want something that's less maintenance than a chain, capable of handling more power than a belt, and less inefficient than a shaft or hydraulic final drive. Surely using gears for the final drive would be somehow bad (even if I mounted the motor on the swingarm near the frame).

I've also thought about two wheels - less resistance. But I think the convenience of low speed stability is worth the extra wheel.

Tilting is tempting. "Cars lean the wrong way in turns." But I think with this geometry, tilting wouldn't gain me much.

I want to wrap the upper (suspension) wishbones and steering rods in fairings.

It would end up getting registered as a motorcycle due to having three wheels. I'm not sure how difficult it'll be to register in New Hampshire, US, but I think not too bad.

Where can I get wheels / tires around 26" tall and 3" wide, and 30" tall and 6" wide?

I have effectively no experience, but this is all stuff I'm very interested in learning. And I realize figuring out how to get sheet aluminum into that shape and welding it together is a lot of learning. Anything I should know about, other than hammering and English wheels? I don't even have any idea what type or thickness of aluminum is appropriate.


The grey box in the middle of the front suspension is the charger.

Of course I'd prefer a custom molded canopy, but I think cutting flat sheets of safety glass (worst case: cut up used car windows) is going to be much more obtainable.

I'm thinking motorcycle type handlebars, with a single rod running to a lever attached to the steering (old(?) drag racer style), and motorcycle type (un-powered disk) brakes. Doing three independent brakes is tempting (one for each foot, one at the left hand, accelerator at the right hand) for control, but I think I'd prefer just doing a single brake pedal and an accelerator pedal for convenience.

I've been playing with related ideas for a few years: http://www.eternalmachinery.com/

[toddshotrods]

I would be the last person to tell someone they can't do something (I live by the anything is possible philosophy) but you are talking a HUGE step; for any type of automotive project. You said you are willing to learn, so it is possible. With your experience/knowledge level, you will spend much more time learning than you will building. There are a handful of scratch-built, and serious custom, projects here on the site. I would recommend you read the entire threads of each before you do anything. You'll not only see the vehicles being built, but kind of experience the challenge from the builder's perspective. Pay attention to post dates. Many times you will see long gaps between posts. Sometimes it just takes a while to catch your breath; sometimes it's figuring stuff out, finding stuff, etc.

Any scratch-built, or serious custom, project is an enormous challenge; mixing the EV aspect in doubles the complications and hurdles. I'm not trying to discourage you, just prepare you. The worst thing in the world is getting knee-deep in a dream project, only to find it's a nightmare, and running out of drive. You can find them in classifieds year-round, every year. You'll see phrases like, lost interest, no time, been sitting for months/years, etc. That usually means it wasn't what they expected, and they're bailing out. The TV shows make it look glamorous, and the challenges almost fun to overcome. In reality, even in multi-million dollar shops, it is incredibly exhausting at times.

All that being said (can't say you weren't warned ) - it is the greatest experience ever! I've been doing custom work for nearly three decades, and am in the midle of my first scratch-built project. In my thread, I said a few times that it will likely be my last - no way! I already have ideas of what I would do next, and none of them go back to simple modifications of pre-existing vehicles. If I were to use one, it would still be scratch-built except for the original shell. In fact, I even started another one already - an e-bike!

• My race rod project.
• My e-bike.
• Coolest tractor ever.
• Coolest bug ever.
• Exotic concept.
• Go kart.
• Three-wheeler (what happened to him?).
• Ground-up Trike (had to go back to pg 23 to find it!)

You can also watch some of the conversion threads to see the hurdles they faced, and how much effort went into solving the issues. That'll give you an idea of what just building an EV takes. Just try to be honest with yourself about how far you're willing to go/how much drive you'll have when it's gets challenging.

Regarding your specific plans, rolling and shaping a metal body like you have planned is pretty intense. That is a serious craft to learn in and of itself, and you're planning to try to learn and master it while building an EV from scratch - big bite, don't choke! There are fiberglass belly tanker bodies that would put you in the neighborhood. Google it - one company that I know has them is Rod-n-Race. I have no experience with them, have considered purchasing from them but didn't, heard good and bad reviews from previous customers...

Automotive glass is a pain to deal with. The windshields can be cut, but even really experienced glass shops will tell you no guarantee - it might break. Don't even think about cutting the other windows - unless you like sweeping up tons of glass chips! Tempered glass can't be cut, it shatters.

If you have motorcyle type steering on a vehicle that size, it's probably going to be VERY heavy! An automotive rack-and-pinion, and steering wheel, would be better.

That doesn't look like nearly enough batteries to get decent range, and I wouldn't want them between my legs!

[Darxus]

toddshotrods: Thanks for taking the time to reply. I realize this plan is ridiculous. But I fail at avoiding taking things to extremes. There's nothing short of this I'm interested in doing.

And I think attempting to make an aluminum monocoque should make a fine hobby for a couple years. Maybe without compound curves, and using a fiberglass nose and tail - I need to see what that looks like. And then the batteries will cost less.

I have read through the turmoil of a number of complete custom ICE builds, and some electric conversions, for years.

Thanks for the term "belly tanker", some sexy stuff. Looks like Rod-n-Race is in the middle of a web site move, and not in archive.org.

I guess I don't see why the steering would be heavier than a big motorcycle. Heh, perhaps because motorcycle steering works entirely differently.

[Duncan]

Hi Darxsus

Go for it - making it yourself is fun

Have a look at Human Powered Vehicles and Solar cars for how to go fast with minimum power.

A couple of points
Non leaning vehicles - look at height of center of mass and vehicle track
For decent cornering you need to be low or wide

Low is frightening on the road, do you need to know what company makes truck diffs?

A leaning machine can be narrow and high

What is wrong with belt drives? I have seen some transmitting several hundred horsepower

A folded aluminium or sandwich chassis would go down well, for the body parts have a look at the mould-less fiberglass system Burt Rutan used on the LongEze

[toddshotrods]

Originally Posted by Duncan

...Low is frightening on the road, do you need to know what company makes truck diffs?...

That's priceless!

Originally Posted by Darxus

...I realize this plan is ridiculous. But I fail at avoiding taking things to extremes. There's nothing short of this I'm interested in doing...

Good, we speak the same language. If I don't kick the bucket, I'll be around to help you find the best way there (extremes). Just wanted to point out the challenges, and see how you responded.

Originally Posted by Darxus

...I guess I don't see why the steering would be heavier than a big motorcycle. Heh, perhaps because motorcycle steering works entirely differently.

Quads, ATVs, four-wheelers (or whatever you want to calll them), and many reverse trikes use handlebars so it can work. I based that suggestion on the fact that you have the battery pack up front and said you want enough batteries for a 100-mile range. I don't know what the actual numbers would be, or even the weight of the batteries you mentioned, it just seems like enough batteries for that much range would come with a weight penalty. That would require more effort to turn the wheels. Even a really fast rack and pinion would give you more leverage.

[fishguts]

I'm an electric reverse trike fan so I dig it. Yep, sure will be a ton of work, but if you're persistent you can see it through. Not what I would recommend as a first project, though. But hey, you gotta find your own way. Good to be talking about "years". I'm in the second year of my project.

How about a couple suggestions?...
-The extremely laid back seating position is going to be real uncomfortable I bet. So maybe something a little more upright? You might want to think through how you'll get in and out of it, too.
-Looks like a fairly slippery design and the wheel pants are cool, but I see you have an open suspension which wouldn't be very aerodynamic. I'm not concerned about it on my project, but then I'm not looking for a lot of range, either. So maybe aircraft strut-like suspension parts or cover it?
-Also, the trailing edge of the wheel pants look neat, but they'll probably limit your turning radius if the pants are turning with the wheels.
-Trikes are considered motorcycles in most places, so your "glass" can be plexi - much easier and cheaper to deal with.
-I wouldn't be surprised handlebars would work out on this. I'm going that route and will be mounting the parts in the next several weeks so can let you know how well it works. I have a rack and pinion out of a 914 Porsche as my plan "B" if I need it.

Do you have a nice, big welding/frame table to lay it all out? Probably going to need one.

Good luck with it. I'm looking forward to seeing it come together.

[grayballs]

Try looking here. I'll bet you can find what you want



http://www.toddscanopies.com/

[TomA]

Interesting drawing and concept. Its like a two-place bobsled, but even more cramped and uncomfortable... ;^) Seriously, its cool and you should build whatever you want to.

Before you get too far, though, you ought to check out your state DMV to see what the licensing regulations there are for your motorcycle class. In NY, a trike seat has to be 20" off the ground, so your design won't be registerable (or insurable) for the road here. You need to avoid off-road (ATV, motocross bike) parts in a lot of states, too. It would be a shame to build something you couldn't got on the road...

Take a look at (Google) Dave Malewicki's California Commuter trike from about 30 years ago. He was on a similar wavelength as your trike. Its a proven and record-setting design, and plans are still available. Buying a set of them from him would get you a long way up your design learning curve for very little money.

Just my $.02.

TomA

[Darxus]

Web page is: http://www.eternalmachinery.com/ecar/

Yikes, I missed comments.



I've been thinking a lot about Aerodynamics. On and off for years. Basically, the consensus seems to be that a teardrop / wing / airfoil shape is the most aerodynamic. I believe, and finally found evidence, that that shape is only used because a pointy leading edge causes sudden and complete loss of lift at varying angles of attack, none of which concerns me. More here:

http://www.eternalmachinery.com/mostaerodynamic/

The human / battery swap was because I was having difficulty with the vertical asymmetry. I'm likely to play with the previous layout more.

My biggest Aerodynamics question is: Is it better to give the air a long, smooth path, or a shorter, still smooth but more sudden path? Specifically as it relates to air flow around my head. I'm guessing for this application it doesn't matter that much. The potential problems are skin drag and boundary layer separation (flow becoming turbulent) over longer distances.

I also squared off the sides to better fit the vertical structural reinforcement panels that go in the sides.


Duncan:

Actually one of the recent steps in this process was looking into the feasibility of creating a highway bicycle for my 35 mile (each way) commute. Turned out I would need to be awful close to a world record holder - and they're on groomed courses.

This design involves nothing between my my butt and the pavement but a single layer of sheet aluminum. The 7" of clearance is negotiable. And I want it as wide as is practical. Maybe I should go a little wider. I'm comfortable with being within licking distance of fast moving pavement.

I've done motorcycle track days a few times. Good stuff. I once slid across the front straight at Loudon NH, watching my bike spin along with me. It was great fun, seriously. This is relevant in two ways: I really am comfortable within licking distance of fast moving pavement, and I'm really disappointed with the failure mode of motorcycles. A little too much throttle, a little too much lean, and a pavement transition, and suddenly you're on the ground. I felt betrayed.

Thanks for the tip on belt drives. Got any links? I fear a very wide belt would be necessary, and aerodynamically inconvenient.


toddshotrods:

Yup, and you were right about the number of cells. I upped the count to 56 (Thundersky 90 amps), which comes out to 395 pounds. Yikes.


fishguts:

I don't see why the extreemly laid back seating position would be uncomfortable. Maybe I should try sitting in a mockup for a couple hours before I start fabricating. (I'm interested in mockup material suggestions - I probably just need to look for myself at home depot.)

Yeah, I've thought a bunch about front suspension fairings. I've played with a couple possibilities, but keep wondering if it's really worth it. Largely because F1 cars don't seem to bother, although I don't know if that's one of their annoying rules (like outlawing turbines and CVTs because they don't sound as entertaining, really). Also, it's a feature that can wait until absolute last. And minimizing half-sprung mass can be good.

You see I chopped off the trailing edge of the wheel pants (I like that term). Didn't seem worth the un-sprung bulk.

It would be great to be allowed to use acrylic, but I worry it wouldn't take long for it to get annoyingly scratched up by highway gravel. I wonder how well they buff up. Any experience with acrylic windshields?

I look forward to hearing how your steering turns out.

I have nothing. Except space and time.


grayballs: Awesome canopy link, thanks.


TomA:

I think of it as cozy
I really like the idea of the body panels keeping me snugly in place.

I actually just emailed the DMV today. Sucks to hear about that 20" limit.

Thanks for giving me Dave Malewicki's name. I was familiar with the vehicle and looking for it recently for obvious reasons. I also was not aware he was selling kits, good to hear.

[toddshotrods]

Originally Posted by Darxus

...I don't see why the extreemly laid back seating position would be uncomfortable...

The problem is you have to look forward at the road, meaning your neck would be bent forward. Could be a strain after a while. Recumbent bikes do it though. Every person is different. I like being tucked in a crouching position on motorcycles, while some people would find it extremely uncomfortable...