Critique this performance velomobile idea

General Discussion about electric bicycles.
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The Toecutter   10 kW

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Re: Critique this performance velomobile idea

Post by The Toecutter » Feb 22 2018 7:39pm

Timelord wrote:
Feb 21 2018 6:48pm

No, it doesn't. The statute says it has to have "the ability to be propelled by human power alone." That just means it needs a bike drivetrain that you can pedal if you have to.
Sec. 551.351. DEFINITIONS. In this subchapter:
(1) "Motor-assisted scooter":
(A) means a self-propelled device
with:
(i) at least two wheels in contact with the ground during operation;
(ii) a braking system capable of stopping the device under typical operating conditions;
(iii) a gas or electric motor not exceeding 40 cubic centimeters;
(iv) a deck designed to allow a person to stand or sit while operating the device; and
(v) the ability to be propelled by human power alone; and


This means a self-propelled device with qualities (i) through (v). This statute and the statute concerning ebikes is ambiguous, as this bike could fall under both categories if I had a thumb throttle limited to 20 mph. I've heard of cheap 49cc two-stroke Chinese scooters that do not class as a "motor-assisted scooter" because they need to first be pedaled to get going, and thus don't fall under the category of "motor-assisted scooter".
"Highway" in Texas-speak means public road. I'm pretty sure if you kept the right as on a bicycle, you wouldn't have any problems on a 40mph road that allows bicycles. I sincerely doubt you'd be allowed to ride an ebike on "any" highway, specifically high speed limited access interstates where motor assisted scooters would be prohibited.

But do what you want. I suspect it won't be as easy as you think.
I have no plans to use an interstate. State highways seem to be fair game as long as I'm on the shoulder or in the right half of the slow lane.
wturber wrote:
Feb 21 2018 7:33pm

Of course, the e-bike doesn't quite meet his needs either given that it is limited to 20 mph under its own power. As soon as he exceed 20 mph, his e-bike is no longer legally an e-bike. If he's zipping along at 30 mph and he gets pulled over by a LEO, he shouldn't be surprised if all sorts of bad things happen.
Here's the statute:

(24) "Electric bicycle" means a bicycle that:

(A) is designed to be propelled by an electric motor, exclusively or in combination with the application of human power;

(B) cannot attain a speed of more than 20 miles per hour without the application of human power; and

(C) does not exceed a weight of 100 pounds.


If I set it up as a pure pedelec, human power will be required at all speeds, thus the 20 mph limit would no longer apply.

That being said, none of this is any guarantee I won't be harassed, but legally, I won't technically be violating state law by using this vehicle. I think I will be ok. I've already passed by cops at roughly 30 mph and haven't been pulled over. I don't have a motor in it yet, but had the suspicion arose, they wouldn't have found one.

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The Toecutter   10 kW

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Re: Critique this performance velomobile idea

Post by The Toecutter » Mar 23 2018 11:59am

I got some more pics last night with a friend's phone:

Rear view:

Image

Quarter view:

Image


I'm going to source material for a windshield today. The roof piece and turtle deck piece are finished but not yety installed. I'm also going to install the sealing tabs on the mid-section piece so that there are no gaps for the air to penetrate on the sides, reducing drag further.

It's much faster than I thought it would be, but I don't yet have a torque sensor or objective way of measuring power requirements to figure out CdA, Crr, and drivetrain losses. The goal is a CdA of 0.15 m^2 or less. I don't think it's there yet, but it will probably get there.

Note the new rims. The KMX rims kept breaking spokes. On Monday I had a local bikeshop lace some Velocity rims to the proprietary KMX hubs. It brakes much more straight now since hard braking kept destroying spokes on the stock KMX rims resulting in me having to make frequent adjustments.

The wheel discs will go back on the rims after I have them checked out and adjusted by the bike shop next week.

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adam333   100 W

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Re: Critique this performance velomobile idea

Post by adam333 » Mar 24 2018 3:22pm

Nice :D

It will probably be very hot to pedal the trike in summer time though.

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The Toecutter   10 kW

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Re: Critique this performance velomobile idea

Post by The Toecutter » Mar 25 2018 12:40am

I have a working cooling duct in the front that directs air to my neck. I will also be adding NACA ducts in the mid-section door piece for armpit cooling.

I rode it for about 25 miles today in 77 degree weather with a loaded trunk(50+ lbs of stuff) and it didn't feel that bad. I probably could have covered 100+ miles like this with enough food and water.

This body is still only the 1st prototype. It wasn't anything fancy, but a practical "get 'er done" solution that is reliable and useful. It will serve as a great template for the next design iteration because all of the mounting, ergonomics, clearances, and other practical aspects are already worked out. I can use this thing as a bicycle-car, and fairly reliably, without even having put a motor in it yet.

For the same amount of effort as a light jog, going into a stiff 15+ mph headwind I was able to maintain a 90-100 cadence using the 48T front ring, 21T rear ring on a 26" rear wheel for about 3 miles straight before the road construction necessitated turning onto a side road that had speed bumps. On the way with the wind on a different set of streets, I was able to do roughly 90-100 cadence using 48T/16T for front/rear cogsets.

I bet I could have gone 20+ miles like that in either case. Almost a month ago, I rode 100 miles in a 24-hour period without the midsection piece installed and probably could have gone another 50 before resting for the night.

This thing is awesome. I really badly want the chance to try out a commercial velomobile because it would be undoubtedly greatly more efficient and faster.

I have something envisioned in my head but undrawn that looks like a sort of mix of elements between a Panhard CD Peugeot 66C streamliner, LeMans velomobile, Lotus 119B gravity racer, and an Infiniti Prototype 9 designed in a way to minimize aero drag for the given chosen shape style and practical constraints. I might be able to do a prototype shape in coroplast. I think such a shape on my KMX done right has potential to get a CdA in the 0.09 m^2 range or less. I would need to model it and test it, but we'd be talking about a frontal area around 0.45 m*2 necessitating removal of the steering arms and implementation of rack and pinion steering. This would make it competitive to a Quest, Strada, or Mango velomobile if this were to be achieved, and I know it is possible for an open-wheeled vehicle to get a Cd in the 0.2 range(Rumpler had a 0.28). I think it could be a very aesthetically pleasing, reasonably safe, practical, and not expensive to produce or replicate design when the physical concept is built.

As far as a rack and pinion steering goes, I am thinking of using a butterfly steering wheel(similar to the style in some aircraft) with clearance for my legs/knees, trigger shifters on both sides as well as brake levers, with the right brake lever controlling mechanical discs in the front as well as the trigger shifter for the front chainring, while the left brake lever would control motor regen and left trigger shifter controlling the rear chainring. This would allow me to use the regen as my default brake with my left hand and would be the one commonly shifting gears and the mechanical discs brakes would be used as a panic brake or supplementary brake with my right hand's fingers always in reach and only rarely moved to activate the front derailleur.

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1JohnFoster   1 kW

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Re: Critique this performance velomobile idea

Post by 1JohnFoster » Mar 28 2018 10:14pm

In a velomobile you can have shade over most of your body. You can get as much air flow cooling as you want just by opening up the bottom at the front and if you have a kamback, open the back.

Better than, for example, a motorbike stuck in stop & go dressed in black and always fiddling with your visor to keep from baking your head. A bicycle can get pretty roasty too if you get blocked by cars and can't move in the sun.
This thing is awesome.
Congrats, I'm jealous!
~mix of elements between a Panhard CD Peugeot 66C streamliner, LeMans velomobile, Lotus 119B gravity racer, and an Infiniti Prototype 9
Seems that retro-streamlined is your theme in keeping with your Triumph. I always liked the Velayo velomobile, probably not the most aero, but a nice way to way solve the velomobile "knee lump" aesthetic problem with retro aesthetics. Also it looks higher and more visible than a Quest et al.

I always wanted to try to blow coroplast, but like so many things, I'll never get around to. I did do a butterfly steering wheel on my hovercraft when I was 18, and it was cool! Does seem like a more practical way to mount shifters, brake levers & throttle than on a multi-turn round wheel - I didn't ever effectively solve those practical "little details" on my VM.

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The Toecutter   10 kW

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Re: Critique this performance velomobile idea

Post by The Toecutter » Mar 28 2018 10:42pm

Coroplast is the easiest material I have ever worked with. You don't "blow" it, you cut out the shapes you need and hold them together with punched holes, zip ties, c-clips, loctite, coroplast tab pieces, and gorilla tape. It's stronger than fiberglass in certain measures. It's also flimsy, a trait that deceives with regard to its real strength.

In a few days I will begin riding it back to St. Louis for a total trip length of 1200 miles.

Once back home, I can finish up the GT6 and build a more efficient body shell for this vehicle.

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1JohnFoster   1 kW

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Re: Critique this performance velomobile idea

Post by 1JohnFoster » Mar 29 2018 3:00pm

In a few days I will begin riding it back to St. Louis for a total trip length of 1200 miles.
Hope you have a great trip! Good to see you have a bit of time for something other than work... hope you stop to eat, drink and meet some people...
You don't "blow" it
Who says you can't? it'll get stiffer, nicer looking and more aero. Bob Stuart suggested it for future of his "X-4 Cycle Car" https://microship.com/bob-stuart/ - near the bottom.
Holes and zip ties are ugly and unnecessary. I use 3M VHB tape on inside verticies and colour matching tape on the outside. I've made mostly flat folding things; Kayaks, temporary blind and shades for working outdoors, carry cases, and currently a flow measurement hood for ASHP. I only resort to zip ties for kid projects.
The Toecutter wrote:
Mar 28 2018 10:42pm
It's also flimsy, a trait that deceives with regard to its real strength.
All flimsy sheet materials can be stiffened with gently curved vertices- like the 1/8" plywood VM in my avatar. Coroplast is friken hard to cut in smooth curves. I use long 1/2's as giant compasses with the X-acto blade clamped to the end. Or bent wood guides screwed down.

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The Toecutter   10 kW

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Re: Critique this performance velomobile idea

Post by The Toecutter » Aug 12 2018 1:46pm

Someone took some videos of it going down the street:

https://vimeo.com/284616898

https://vimeo.com/284616919

The aluminum body I started on is halted due to temporary lack of access to a friends' shop. I'm working on a more streamlined plastic body shell now. The money I set aside for the electric drive system was used to save my mother' house from foreclosure, so until I get that back or can get enough work to sae up the money I need again, I won't be putting the electric motor/battery/controller/other stuff in it.

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The Toecutter   10 kW

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Re: Critique this performance velomobile idea

Post by The Toecutter » Oct 02 2018 12:35pm

Having spent an entire summer riding this thing and racking up thousands of miles, I can say that it is a bit cooler to operate than a normal bike, as long as I am moving. It gets very hot when stopped at a stop sign or traffic light, but once the air starts to move through the vent, it becomes comfortable. There's been a few times where I've ridden over 100 miles in a day and I did not feel worn out or fatigued.

I've also been more than 50 mph downhill and the trike remained stable even when making lane changes. One has to put in a lot of effort or do something stupid to get it up on two wheels, but I've done such deliberately at lower speeds.

The body is becoming quite worn though and I need to finish up the replacement body and get it on ASAP. A few weeks ago it started wobbling at greater than 40 mph speeds because of creases that have formed in the plastic that have destroyed its former stiffness, and at those speeds, the wobbling is enough to change the trike's trajectory and require steering changes to correct it.

I'm hoping the next body will have significantly reduced drag over this one. As is, the amount of power I can pedal with for hours at a time will allow this to maintain 21-22 mph or so on flat ground, and when going all out with full strength, I can reach about 33-35 mph on flat ground. With the next body, I'm hoping to raise cruising speeds to 25+ mph and top speed to 40+ mph.

I did some coast down testing and came up with an estimate of a CdA of 0.25 m^2. Compared to a commercial velomobile, that's a terrible amount of drag. The Quest velomobile has a 0.08 m^2 CdA for comparison.

There are a lot of sources of drag on my velo that need to be addressed. I have a large vent with an unoptimized air duct in the front for cooling, the mirrors are flat at the front and protrude out of the hood piece, there's no turtledeck, there's a large opening where my head is, there's no boot pieces to seal where the brake lines and suspension stick out from the sides, there's massive foot holes in the bottom of the floor, the trunk lid has 1/4" gaps that are allowing the trunk to act like a massive parachute in the rear, the longitudinal vertices are generating lots of vortices, and the top-down profile does not perfectly track the NACA0026 airfoil I used as a template because I had to elongate the front in order to have enough pedal clearance which in turn makes the entire tail section a massive turbulence generator because it's not shaped properly for the front of the vehicle.

The next shell, it is possible to get the frontal area around 0.5 m^2. I'm using a NACA0020 airfoil as a design template, and unlike the previous design, I'm not distorting the airfoil in any way when looking at it from the top down perspective, so I know the tail is going to be the correct shape for the front. I am going to keep frontal area down by having holes cut into the sides for my steering bars, with spandex boots made. The shell will be exactly the width of the steering bars at its widest point, and the spandex will stretch outward during cornering. There will be a series of small NACA ducts for cooling on this new one, instead of a large vent in the front.

The open wheels are being retained because this configuration is easy to work on and maintain, even though they are terrible with regard to drag. I've had to change a tire and tube 20 miles from home on a sidewalk already and the open wheels made the task extremely simple compared to what it would have been had the body covered the front wheels.

Getting it as efficient as possible with practical constraints in mind is the goal. The next shell should have improved aero, but I know for certain it will have about 30% more storage space and better cooling, as well as a windshield and roof for winter/rain riding. I want to get the CdA of the next iteration to under 0.15 m^2. The possibility of retaining the open wheels and getting as low as a 0.09 m^2 CdA does exist, but getting there without access to a wind tunnel may be difficult.

I'm quite pleased with the results of using a KMX with adam333's front suspension kit. I just need to get the money together to finish it with a drive system. I'm sure the fun factor will increase dramatically with a Leafbike motor and 4 kW to start out with(and the possibility of 5-6 kW with modifications).

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adam333   100 W

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Re: Critique this performance velomobile idea

Post by adam333 » Oct 03 2018 1:24pm

Thanks for the kind words.

And yes, you will definitively enjoy it even more with a 4kW motor :D

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