My first scratch build: 30kw full suspension tandem velomobile.

[tymotors]

Hello everyone,

I have begun the process of building my car replacement. I have built a few bikes, including a hybrid electric one with a generator for effectively unlimited range, but there has always been a problem: E-bikes suck at being aerodynamic, and so are limited to below 30mph if you want to go any reasonable distance without building a battery with wheels stuck to it. This has limited the distance I can do in one day to about 200 miles, which takes about 10 hours with my hybrid bike. If I want to compete with a car, I need to be aerodynamic and highway legal. Also, I want to be able to share the experience with other people. For range, I want to go at least 400 miles on the highway to outperform almost every electric car on the market and make even the electric car owner with the $100k Tesla question the merits of the conventional electric car.

How the heck do I plan to do this?

The main requirements are about 15kWh of capacity, at least 30 kW of motor for good acceleration, and an aerodynamic shell so I can achieve my range goals. I also need to go 80mph uphill comfortably to cruise on the highways without being an obstruction. This will be taken care of by the high voltage battery + fast wind motor.

The frame:

I was forced to build my own frame since google basically laughs in your face when you search for a tandem full suspension trike, and I don't have 8k to spend on a frame I will have to modify anyway.

I have gotten about halfway through building a modified atomic zombie tandem trike frame, the modification being full suspension because highway speeds without suspension are scary. I also lowered the ground clearance for better aerodynamics once the shell goes on.

The shell:

I am following in the footsteps of John Tetz and his Foamshell Velomobile. I chose this route because of the reduced expense, reduced weight, and the better acoustic performance a foamshell will provide. I may have to reinforce the top hatch and head area. I will hopefully be using a waterjet cutter at school to cut out some insulation foam to minimize the human error present in the mold. The shell will be make or break for this vehicle. If I do a bad job, I will be lucky to get 300 miles of range. If I do a good job, I might be able to break 500 miles. The good thing is that this is a body on frame vehicle and that I can always try again if the first attempt is a disaster.

The powertrain:

I will be using QS 273 45H 2T in a 16 inch moped rim, controlled by a Tronic 750 (or possibly a powervelocity next gen if mine can be fixed), fed by a 32s (115v) 135ah battery undercharged to about 130v or so. I will be temporarily using a QS 205 3T in the same size wheel in my possession for testing to spread out these expenses. The 205 should be able to handle most situations without saturating, but the 273 will make this thing fast. I am curious to see how much the no load current of the 273 reduces efficiency at 60mph.

Question for the forums: What is the maximum instantaneous torque that these motors can provide if not limited by heat or phase amp supply, where beyond this adding more amps doesn't make more torque? I know about magnetic saturation, but the windings act like an air core motor beyond this. LFP found this limit in one of his tests years ago, where adding more current added nothing but heat and resulted in a combusting motor. I am ok with going past saturation for quick accelerations, but I don't want to make more heat than necessary.

Steering and suspension:

I plan on using powersports parts for the steering (go kart steering rack), and a double A arm front suspension. The rear will be a simple swingarm.


The annoyingly important tiny little details:

I need to make this thing road legal, since a state trooper is going to pull over anything without a plate on the highway. Any recommendations from people who have made a scratch build road legal before?

I have some bushings for the rear swingarm, but I am not entirely sure how to mount them. I know I need a bearing sleeve for the outside, but what goes in the inside?

Any ideas for mounting a motorcycle visor to the foamshell for a windshield?

I will post pictures of my progress later tonight.

Thanks for reading, suggestions are always welcomed!

 

[scianiac]

Making this road legal is going to be an interesting challenge, assuming it's going to be a trike registered as a motorcycle which honestly is your only hope and even that will require some interesting interpretations of the vehicle code. Most states have ways to register a custom or composite motorcycle but those at least suggest that it's built from other motorcycles although rarely specify how much of the original motorcycle you need to use. If you live in a state with inspections that's going to be a whole different issue and if you don't you're still going to run a risk of being ticketed for who knows how many possible things if you get pulled over.

And all of this assumes you'll actually want to drive it anywhere around fast traffic, I sure as hell wouldn't. Assuming all your engineering is 100% perfect so it's stable and safe at those speeds the chances of you getting run over because you might as well be driving around a 2ft tall stealth bike. If that's the northern part of New England you'll probably be OK on fast back roads in good weather during the day, if that's the southern part of New England start writing your will now.

Maybe I'm being too negative, probably because I too think this is a super cool vehicle and would love to build something like it, right up until I think about driving it in any traffic. It's great as long as there aren't many cars around so maybe it just depends where you intend to drive it. If you do build this at least take the slight drag penalty and put a tall fin on it with lights.

 

[Chalo]

I want to be able to share the experience with other people. For range, I want to go at least 400 miles on the highway

[...]

The main requirements are about 15kWh of capacity, at least 30 kW of motor for good acceleration, and an aerodynamic shell so I can achieve my range goals. I also need to go 80mph uphill comfortably

[...]

I am following in the footsteps of John Tetz and his Foamshell Velomobile. I chose this route because of the reduced expense, reduced weight, and the better acoustic performance a foamshell will provide.

[...]

I need to make this thing road legal, since a state trooper is going to pull over anything without a plate on the highway.

I applaud your goals here, but you're dreaming. Anything that ticks all your performance boxes will be a whole lot more like a car that wishes it were an airplane, than like a velomobile. 80mph will tear off that foam body and throw it away (maybe followed by you). The drag and rolling resistance numbers you'd have to achieve to get 400 miles on 15kWh at car speeds are out of your reach. By the time the thing has enough structural integrity to do what you propose, you'll have beefed it up enough to be better off having started with a vintage two seater car.

Decide which of your conflicting requirements you're willing to let go of, because you have too many of them stacked up right now. I recommend sacrificing range to start with, because no normal human wants to wants to ride in a coach class coffin on wheels for 400 miles. Not even you.

Also, check out Toecutter's velomobile threads if you haven't already. He has been hitting the same crack pipe as you, just a little less hard. He has some creditable real world results to show for it.

 

[neptronix]

Legalizing such a vehicle is going to be impossible.

You best bet is a modified motorcycle chassis as the base, as Craig Vetter was doing... If it has a VIN, there's a less difficult path to legalizing it as a motorcycle. There is no legalizing a self-built bike frame for road/highway usage.

 

[Chalo]

Legalizing such a vehicle is going to be impossible.

An NEV/LSV version of it would be registerable in many places. But that would be an entirely different speed and power regime, and it comes with access limitations.

You best bet is a modified motorcycle chassis as the base, as Craig Vetter was doing... If it has a VIN, there's a less difficult path to legalizing it as a motorcycle.

This is where I'd start. MC from the transmission back, cuckoo bird stuff up front.

 

[99t4]

I have built a few bikes, including a hybrid electric one with a generator for effectively unlimited range...

This is very interesting. Do you have a build thread of it?

 

[neptronix]

LSV/NEV is basically a useless legal category.
It's not unlike street legal ATVs here in some parts of Utah..
..you can technically build a mid-weight vehicle but there are so few places they are legal.

You can sure do a lot with the motorcycle category..

 

[Chalo]

You can sure do a lot with the motorcycle category..

View attachment 346190

Yes, especially because three wheelers qualify for that category. But in my opinion, two front wheels and side-by-side seating would make the frontal area of this vehicle too big to get the implied drag numbers. Single track and tandem seating would make it more feasible.

Ecomobile/Monoracer is about the closest production item I can think of to what the OP proposes. I'd be very interested to see their power, battery, range, and performance figures for the electric version.

 

[neptronix]

I love how that vehicle becomes 'not a 4 wheeler' during motion, and is therefore not a 4 wheeler.
You sure can bend that motorcycle rule a lot..

..imagine making a sondors EV type car but more bubble like... somewhere in the heavy motorcycle range of weight.

I really like the taller height and less crazy emphasis on aero, which means other cars can see you on the road plenty well..
..you can't achieve absolute efficiency in a road vehicle for very long if you can't been seen by a semi..

 

[tymotors]

Thanks everyone for your input. All good ideas sound crazy from the start. Good thing I am crazy enough to push forward with this, and if I fail, it will be a great example for everyone to learn from.

The fin idea I think is a really good one actually. It solves 2 problems at once, visibility and crosswind stability. A protruding fin up to the height of a car window is something I will seriously consider for safety and stability reasons. The drag will be minimal if I make it an airfoil shape.

The 2 seats will be inline for efficiency.

I will be talking to the dmv soon about registration. The motorcycle category is indeed a loose one, and there are ways to get a VIN for a custom build like this. People build motorcycles from scratch so there are provisions in the law as I understand it.

I already have the batteries, motor, and controller. No sense in not using them. If I end up with less than ideal shape, I will have at least 150 miles of range (calculated with no shell), which will be plenty useful. We will see how I like sitting in my “death trap” (as toecutter’s has been called in the past) for hours on end. I already have a few 10 hour ebike rides under my belt. I enjoyed every second. I think there is indeed something wrong with me.

Single track is something I considered for a while because of it’s simplicity and efficiency, but crosswind instability and the inability to use it in winter pushed me towards an inherently stable design.

The point chalo made about the foamshell is a good one. I will at the very least need to mount it securely and possibly build an exoskeleton like structure to support it.

 

[scianiac]

I think you will find that making the whole vehicle a bit larger than I think you first envisioned will help a lot, yes you will gain frontal area but if I were you I would rather have an end product that is more usable, more stable, more comfortable, more durable, etc than one that has a crazy range. So using more motorcycle parts, perhaps the whole rear swingarm and suspension for instance will make it solid and then you'll have a better chance of registering it as a custom/composite motorcycle using the Vin of the wrecked bike you started from. Think a slightly smaller and much more aero version of the common 3 wheeled trike motorcycles out there. Even making the frame more like a triangulated rollcage.

 

[tymotors]

This is very interesting. Do you have a build thread of it?

Sorry, no build thread. Perhaps I will make a post about it. Here is a picture:

 

[Chalo]

The point chalo made about the foamshell is a good one. I will at the very least need to mount it securely and possibly build an exoskeleton like structure to support it.

People build canoes and kayaks out of very thin flimsy wood, covered with fiberglass and resin. Maybe something like that would make a foam fairing usable at high speed, without making it disagreeably heavy.

 

[tymotors]

People build canoes and kayaks out of very thin flimsy wood, covered with fiberglass and resin. Maybe something like that would make a foam fairing usable at high speed, without making it disagreeably heavy.

The nosepiece at the very least will have fiberglass to deal with the very tight compound curve, John Tetz found it to be necessary in his notes on the process. He also devised many ways to stiffen the shell with foam U beams and such. I’m sure I will need to experiment to find the right balance.

 

[99t4]

"I have built a few bikes, including a hybrid electric one with a generator for effectively unlimited range..."

Thanks for the photo that explains it. Gasoline generator AKA range extender.

 

[DaLanMan]

I need a pic of my neighbors "green tech" vehicle...

She raises Llama's, she has trained her Llama's to pull her "llama walking" cart, in whish she sits while the llama's wander around (I don't think she is doing much guidance, normally she is reading on a Kindle)

That is the ultimate in range extension... Just let them niblle on the verge occasionally.

(pauses and re-reads the commentary)

Hey Chalo, does that make sense to you? or do I need to call off thinking for another day of recovery?

 

[hobbyvac]

This concept may have some features you can copy. I worked on this and a few other prototypes in the early 80's It went by several names. "BD200 Autocycle", "Lightstar" and "Pulse" I built prototypes in the beginning then the project changed owners and 400 cars were built in Owosso Michigan. It was a tandem seating aero concept vehicle. It used a small two cylinder motorcycle drive train with two small "outrigger" wheels raised slightly so only three wheels ever contacted. It achieved a real 100+ mpg on regular roads with me driving and measuring gas. I put about 3000 miles in testing including time at the transportation research centers 8 mile banked oval track. I worked for the late Jim Bede who was an a aircraft designer. His son in Florida is building an electric version. This is not just aero styling, the aerodynamics were real and effective. It had a crazy low drag coefficient and went a lot faster on less power than the donor bike could. I think the concept has merit but the rushed prototypes were always too heavy with quirky handling with structural and safety issues. The body was fiberglass and it was a non leaning design which I hated because I was a motorcycle racer at the time. Jim Bede Jr is bringing this back as an electric so you can follow it here. AutoCycle Corp – A New Generation of Electric Motorcycle

 

[tymotors]

This concept may have some features you can copy. I worked on this and a few other prototypes in the early 80's It went by several names. "BD200 Autocycle", "Lightstar" and "Pulse" I built prototypes in the beginning then the project changed owners and 400 cars were built in Owosso Michigan. It was a tandem seating aero concept vehicle. It used a small two cylinder motorcycle drive train with two small "outrigger" wheels raised slightly so only three wheels ever contacted. It achieved a real 100+ mpg on regular roads with me driving and measuring gas. I put about 3000 miles in testing including time at the transportation research centers 8 mile banked oval track. I worked for the late Jim Bede who was an a aircraft designer. His son in Florida is building an electric version. This is not just aero styling, the aerodynamics were real and effective. It had a crazy low drag coefficient and went a lot faster on less power than the donor bike could. I think the concept has merit but the rushed prototypes were always too heavy with quirky handling with structural and safety issues. The body was fiberglass and it was a non leaning design which I hated because I was a motorcycle racer at the time. Jim Bede Jr is bringing this back as an electric so you can follow it here. AutoCycle Corp – A New Generation of Electric Motorcycle View attachment 346247

Thank you!

 

[DaLanMan]

This concept may have some features you can copy. I worked on this and a few other prototypes in the early 80's It went by several names. "BD200 Autocycle", "Lightstar" and "Pulse" I built prototypes in the beginning then the project changed owners and 400 cars were built in Owosso Michigan. It was a tandem seating aero concept vehicle. It used a small two cylinder motorcycle drive train with two small "outrigger" wheels raised slightly so only three wheels ever contacted. It achieved a real 100+ mpg on regular roads with me driving and measuring gas. I put about 3000 miles in testing including time at the transportation research centers 8 mile banked oval track. I worked for the late Jim Bede who was an a aircraft designer. His son in Florida is building an electric version. This is not just aero styling, the aerodynamics were real and effective. It had a crazy low drag coefficient and went a lot faster on less power than the donor bike could. I think the concept has merit but the rushed prototypes were always too heavy with quirky handling with structural and safety issues. The body was fiberglass and it was a non leaning design which I hated because I was a motorcycle racer at the time. Jim Bede Jr is bringing this back as an electric so you can follow it here. AutoCycle Corp – A New Generation of Electric Motorcycle

All while sporting that epic stache, you sir, are a hero!

 

[The Toecutter]

The second passenger will necessitate a significant mass increase over a one-person vehicle. You're probably looking at something that weighs around 250 kg without anyone sitting in it.

The foam you want to use will work great for forming a useful shape. I'm familiar with John Tetz' build and it works, but his was meant for low speeds(sustained < 35 mph). Reinforcing the material with fiberglass and epoxy might give crash protection if you design the crumple zones correctly, in which case you'll also want a roll cage to also prevent being crushed after the material gives way.

At what speed do you want to get 400 miles range? 15 kWh yielding 400 miles range at 80 mph implies 37.5 Wh/mile, and a power consumption of 3 kW at speed. You'd need a CdA value on par with a Milan SL velomobile to do this, which is a much lighter vehicle built to seat one and designed by a legendary aerodynamicist who is now elderly and has ben studying that subject since his teens. Probably not happening, unless you directly copy this shape and scale it to fit your needs(and even then, things will inevitably be off, but this is the route I'm currently taking).

Lower that speed to 60 mph to get that range, and it implies 2,250W, which is much more feasible, at least on flat ground. If you keep the frontal area and drag low enough, that range goal at 60 mph is well within the realm of plausibility on the chosen size of battery pack. You're going to want a frontal area of under 0.7 m^2 and a drag coefficient under 0.2. Area is easier to reduce than drag coefficient, but given your speed requirements and the need for a second passenger, you'll need a minimum track width of about 40" for stability at high speeds, maybe more, with a nice, long wheelbase that is going to make your turning radius horrendous. 0.2 drag coefficient will be difficult to achieve without a wind tunnel, but not unheard of, and will be made easier using airfoils as templates, which can be rotated on an axis to form bodies of revolution. See the following site for useful shapes to use in your models:

Airfoil Tools

Airfoil (aerofoil) tools and applications. Search for airfoil coordinates and dat files. Plot and comapare airfoil shapes

airfoiltools.com

I used the above site to design my own custom body shells, an they both worked reasonably well. The outboard wheels and exposed control arms ended up accounting for most of my drag.

 

[thebeachtoday]

What state are you in? I can help get you in the right direction. It's not as hard as everyone says, but you have to just kind of "get it" when it comes to dealing with state DMVs. I ended up getting licensed in Florida as a motor vehicle manufacturer with direct to consumer sales. I've delayed the sales part indefinitely. You can get all this done for $300 license fee and 20 pages of details that I can share with you as a boiler plate. It's not tough, but you want to go down the right path you start with. DM me. Good luck. You got this!