Critique this performance velomobile idea

General Discussion about electric bicycles.
User avatar
The Toecutter   1 kW

1 kW
Posts: 405
Joined: Feb 08 2015 4:02pm

Re: Critique this performance velomobile idea

Post by The Toecutter » Mar 07 2015 5:17pm


whatever   100 kW

100 kW
Posts: 1126
Joined: Jun 03 2010 2:16am

Re: Critique this performance velomobile idea

Post by whatever » Mar 17 2015 7:50am

you mentioned 31" height, is that the height of the top of your canopy? If thats the height of the base of the vehicle, it will be extremely unstable on corners, probably ususeable, even a decent cambor in the road will tilt it over dangerously.
The height of the base of the vehicle should be as low as possible, just a few inches off the ground.
Everything changes if you have a tilting trike.

User avatar
The Toecutter   1 kW

1 kW
Posts: 405
Joined: Feb 08 2015 4:02pm

Re: Critique this performance velomobile idea

Post by The Toecutter » Mar 18 2015 10:25pm

31" will be the top of the canopy. Stability won't be an issue much, but visibility to motorists certainly will...

Eskimo   10 kW

10 kW
Posts: 503
Joined: Feb 25 2013 9:16am
Location: Helsinki, Finland

Re: Critique this performance velomobile idea

Post by Eskimo » Mar 20 2015 1:10am

Rode my velomobile with a motor first time yesterday. Hilarious machine, great fun. Hits around 28mph without pedaling and that"s pretty much as fast as you wanna go with it without suspension though i pedal it too. Comfy cruiser around 20mph. Did not burn more electrons than my upright even though it"s good 25lb heavier. Confuses the hell out of the people, folks try to figure out is it a car or not. Waiting the lights noticed that the whole bus aside me was staring at me hard :wink: People give a lot of thumb ups. Good thing about it is that you can pack 30-40Ah, and you don"t feel it at all and it"s all there under the hood. Steering still needs some work, tougher parts. Some alumium parts i use now flex a bit, which makes steering bit wobbly on higher speed. Steel parts needed.
Member of a 10 000 mile club
http://helsinkiheroes.com/

tahustvedt   10 kW

10 kW
Posts: 595
Joined: May 26 2014 9:31am
Location: Northern Norway

Re: Critique this performance velomobile idea

Post by tahustvedt » Mar 20 2015 8:16am

Eskimo wrote:Rode my velomobile with a motor first time yesterday. Hilarious machine, great fun. Hits around 28mph without pedaling and that"s pretty much as fast as you wanna go with it without suspension though i pedal it too. Comfy cruiser around 20mph. Did not burn more electrons than my upright even though it"s good 25lb heavier. Confuses the hell out of the people, folks try to figure out is it a car or not. Waiting the lights noticed that the whole bus aside me was staring at me hard :wink: People give a lot of thumb ups. Good thing about it is that you can pack 30-40Ah, and you don"t feel it at all and it"s all there under the hood. Steering still needs some work, tougher parts. Some alumium parts i use now flex a bit, which makes steering bit wobbly on higher speed. Steel parts needed.
What does your velomobile look like? I can't find anything by googling the name.

Eskimo   10 kW

10 kW
Posts: 503
Joined: Feb 25 2013 9:16am
Location: Helsinki, Finland

Re: Critique this performance velomobile idea

Post by Eskimo » Mar 20 2015 8:52am

tahustvedt wrote:
Eskimo wrote:Rode my velomobile with a motor first time yesterday. Hilarious machine, great fun. Hits around 28mph without pedaling and that"s pretty much as fast as you wanna go with it without suspension though i pedal it too. Comfy cruiser around 20mph. Did not burn more electrons than my upright even though it"s good 25lb heavier. Confuses the hell out of the people, folks try to figure out is it a car or not. Waiting the lights noticed that the whole bus aside me was staring at me hard :wink: People give a lot of thumb ups. Good thing about it is that you can pack 30-40Ah, and you don"t feel it at all and it"s all there under the hood. Steering still needs some work, tougher parts. Some alumium parts i use now flex a bit, which makes steering bit wobbly on higher speed. Steel parts needed.
What does your velomobile look like? I can't find anything by googling the name.
Attachments
Kinneri 9 002.jpg
Kinneri 9 002.jpg (127.96 KiB) Viewed 2156 times
Member of a 10 000 mile club
http://helsinkiheroes.com/

tahustvedt   10 kW

10 kW
Posts: 595
Joined: May 26 2014 9:31am
Location: Northern Norway

Re: Critique this performance velomobile idea

Post by tahustvedt » Mar 20 2015 9:03am

Very cool. Is it your own design?

Eskimo   10 kW

10 kW
Posts: 503
Joined: Feb 25 2013 9:16am
Location: Helsinki, Finland

Re: Critique this performance velomobile idea

Post by Eskimo » Mar 20 2015 9:13am

tahustvedt wrote:Very cool. Is it your own design?
Yep. It now has a windscreen. It was inspired by the velomobile boom Finland had in 1948-1952. There was even velomobile races in Helsinki back then, lots of people build this kind of velomobiles after the war, when cars and gas were too expensive and hard to find for a normal citizen few years. I kinda try to mix the tradition with the new. You may find some pics of those if you google "kinneri", which is "velomobile" in finnish. It"s a nice ride with a motor, i think i will not ride much with my cruiser this summer.
Member of a 10 000 mile club
http://helsinkiheroes.com/

xenodius   1 kW

1 kW
Posts: 484
Joined: Sep 03 2012 6:55pm
Location: Spokane, WA

Re: Critique this performance velomobile idea

Post by xenodius » Mar 20 2015 10:25am

Sweet! What's the fairing made of?

Eskimo   10 kW

10 kW
Posts: 503
Joined: Feb 25 2013 9:16am
Location: Helsinki, Finland

Re: Critique this performance velomobile idea

Post by Eskimo » Mar 20 2015 10:38am

xenodius wrote:Sweet! What's the fairing made of?
4mm plywood, which is..1/6 i think. Hood is plastic. Frame is wood and aluminium. 12 meters of aluminium profiles. Total weight with a DD motor and stuff 43kg. Maximum battery capacity 40Ah/48V.
Member of a 10 000 mile club
http://helsinkiheroes.com/

User avatar
docnjoj   100 GW

100 GW
Posts: 5771
Joined: Sep 29 2007 5:26pm
Location: Fairhope AL

Re: Critique this performance velomobile idea

Post by docnjoj » Mar 20 2015 11:07am

That is a cool velo! I like the use of the front forks for the front suspension. Very neat and tidy.
otherDoc
E-bike stable at our house

Steintrike Mad Max full suspension trike rear Cute 100H going on: Whoops, Cute wheel broke but I fixed it.
Sun USX delta trike EbikeKit small geared front wheel sort of front suspension for wife

Agniusm/A123 AMP 20 36 volts on the Steini has been taken off.
2x16000 Multisport from HK now gone as they died after 2 years
New Luna 10S bottle battery 13.6AH now on mine
Relatively New 10S4Px2 for wife's bike giving 20ah @ 40 volts home made Panasonic from Tumich. BMS's rule.

User avatar
The fingers   100 GW

100 GW
Posts: 6327
Joined: Mar 11 2012 11:22pm
Location: Desert Pacific Cali USA

Re: Critique this performance velomobile idea

Post by The fingers » Mar 20 2015 1:12pm

È incantato dalla bellezza della ragazza. 8) Very nice!
Black Schwinn High Sierra
Blue Schwinn Cruiser 5
Blue Schwinn High Plains
Black Fiore Cruzer 5: Amped Warp Drive 26" Front DD/SLA kit
http://ghostbikes.org/
http://www.rideofsilence.org/main.php
Hebrews 9:27

User avatar
The Toecutter   1 kW

1 kW
Posts: 405
Joined: Feb 08 2015 4:02pm

Re: Critique this performance velomobile idea

Post by The Toecutter » Mar 22 2015 10:20am

Eskimo, that is some nice work. How many miles does it go on a charge, and in what kind of riding conditions? Your 1.92 kWh battery pack is roughly the size of battery I want to fit in mine, but depending on my motor and controller selection, I will have to choose my voltage and AH carefully.

It's encouraging that you were able to fit that large of a battery pack, and keep the vehicle mass at only 43 kg! This is my target mass.

My trike has a rear suspension. I wonder how much that would increase my cruising speed? I might find out this week; I've gotten rid of the rust on my trike and am now working on repairing the brakes and gear shifters. Once I have it ridable, I can start working on the body and upgrading some parts(motorcycle wheel and tire on rear, larger disc brakes, Maxxis Hookworm or Roundworm tires up front, thicker spokes on all wheels, thicker dropouts and torque arms on the rear, ect).

The body work on the Velogatti seems to be very drag-inducing. Open wheels and a lack of streamlining won't work for me. I'm looking to make a body of at least similar efficiency to the Ice Trice QNT Borealis or the Quest, so that I can cruise with ~150W of pedaling and no electric assist at all at 20+ mph with all cargo loaded(total mass including myself ~140 kg). On my road bike(total weight ~80 kg), 150W gets me to about 15 mph, and I can do this for many hours without ever getting tired.

I want my electric drive to serve two purposes:

1) Providing a small amount of power over long periods of time so that 30-35 mph can be maintained all day long with me pedaling with ~100W and the electric motor providing another ~200W or so. This could allow me to make long trips in the vehicle.

2) Providing a large amount of power under heavily pedaling for hauling ass and accelerating like a sports car when desired(5+ kW). My first prototype will probably be configured for 50 mph top speed, although I am working on designing a stronger/lighter frame and even considering a monocoque chassis that could handle 100+ mph.

Of course, with regard to my first prototype, purpose number 1 is the more important of the two, in the event a compromise has to be made.

Plywood seems to be difficult to work with if you want complex curves, although plywood body cars like the Tryane II show that it is possible. How much does your plywood body weigh? I'm looking to make mine out of dacron, but might be willing to consider plywood.

I find the history of Finnish velomobiles to be interesting, although the aerodynamics of most of the early Finnish velomobiles don't seem to give much of an advantage over an upright bike. I want the faring mainly for the aerodynamic advantage to be gained, so that will be the focus of my design.

BTW, don't forget to awaken Mustakrakish, the Finnish lake troll:

https://www.youtube.com/watch?v=uCUnhoe0rpU

User avatar
Chalo   100 GW

100 GW
Posts: 7154
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Critique this performance velomobile idea

Post by Chalo » Mar 22 2015 7:32pm

You might be able to use a big multipole switch (break-then-make) to use the same two battery packs in either series or parallel configuration on demand. If your controller tolerates that wide a range of voltage, then (for instance) a 36V/72V switchable system could give you about 30 and 50mph top speeds.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

mvly   10 kW

10 kW
Posts: 915
Joined: May 25 2011 11:50am

Re: Critique this performance velomobile idea

Post by mvly » Apr 05 2015 9:15am

Not sure if you know but here is a great velomobile to start with. It has full suspenaion because it is based off of the mungo stientrike which is full suspension.

http://www.veloverde.net/recumbent-cycl ... order.html

I was contemplating doing something like you said but probably legalize it by having it registered as an experimental vehicle legal to take on the highway.

User avatar
The Toecutter   1 kW

1 kW
Posts: 405
Joined: Feb 08 2015 4:02pm

Re: Critique this performance velomobile idea

Post by The Toecutter » Apr 09 2015 7:22pm

mvly wrote:Not sure if you know but here is a great velomobile to start with. It has full suspenaion because it is based off of the mungo stientrike which is full suspension.

http://www.veloverde.net/recumbent-cycl ... order.html

I was contemplating doing something like you said but probably legalize it by having it registered as an experimental vehicle legal to take on the highway.
Holy crap that's expensive!

For that $7,000, I think I'd be looking for a used Milan SL, if I was looking to buy one already built.

So far, I have about $750 in my project. Getting the disc brakes to work properly is proving to be quite a chore. The total budget when finished is likely to come in somewhere around the $3,000 range, from what I can tell thus far.

Before I decide what motor/controller/batteries to use, I will have to weigh this vehicle as a working velomobile to find out how much excess weight I have to work with. It must me under 100 lbs to be legal. Given that this trike is not as strong as what I could make designing completely from the ground up, I probably don't want more than 1 kW, although having components capable of 10 kW and swapping them into a fully custom design at a later date is an enticing idea.

User avatar
The Toecutter   1 kW

1 kW
Posts: 405
Joined: Feb 08 2015 4:02pm

Re: Critique this performance velomobile idea

Post by The Toecutter » Feb 01 2016 1:05am

I owe this topic an update. A LOT has happened in the year that has passed with regard to this project, but unfortunately, not in terms of progressing it.

I have only ridden the trike a total of 6 times since purchasing it, even though the intent was to get it reliable and regularly used.

I first had it rideable in June of 2015. I used the old part that came on the trike, and had some custom tie-rods fabricated for my Ackerman steering. I went to a local restaurant, parked it there, and came back only to find two punk kids standing on it. They ran away fast. One of the steering rods was bent and I had to have it straightened, which took a month of waiting as I was on vacation from work for the entire month of July, working on my electric Triumph GT6 back home.

In early August, the day after I got my tie rod back, there was a break-in in my apartment while I was at work. My two roommates were present during the break-in, and a melee ensued. There were five would-be thieves. One of my roommates was thrown on the trike, damaging the wheels, disc brakes, tie rods, and a bunch of other stuff. When I got back from work, there was blood everywhere. Fortunately, none of my roommates were badly hurt, but the trike was quite damaged, and the mould that I was constructing to build a body from was a total loss.

A month later, I got it working again, rode it around a bit, and parked it outside of the same restaurant that the two punk kids damaged the tie rods at months ago to get dinner. As I was walking out, it was run over by a black Ford truck, with the asshole driving it speeding off. Lesson learned; I am never parking anything there again, ever.

Fortunately, the frame was not bent. Good and sturdy, which is exactly what I need for this application. Most of the other stuff, on the other hand, was again destroyed.

$300 worth of new wheels/tires/tie rods/other stuff later, plus a complete teardown, rust removal, and repainting of the frame and any other components worthy of being kept, I had it rideable again as of 3 weeks ago upon the arrival of a SunLite dual cable lever that I needed in order to allow both front brakes to be activated with one hand.

The following problems arose(as I knew they would, based on my earlier rides) as I was riding it around the local hood, and the 3rd time I had ridden this vehicle since purchase:

-The rear derailleur no longer worked as it did earlier. It was thoroughly rusted, as to be expected from a custom recumbent built in the 1990s from cheap Chinese-made mountain bike parts. I kept it stuck in 3rd gear for experimenting, with the intent to replace not just the derailleur, but the chain, freewheel, front crankset, cables, and all the usual drivetrain components. It rode very well, aside from the original rear wheel that had a bent axle from the truck running it over and the resultant high rolling resistance. I got it to about 21 mph like that on the flat, but going up hills and starting from a stop was no fun. It should do a lot better when I get a new rear wheel on it...

-Having converted a car to electric, I figured bicycles would be simpler to figure out how to customize. I was wrong. I needed to get this thing to a bike shop so someone could help me figure out what parts were compatible, and get me familiar with some terminology, and later did so(not without a problem, as you will read on).

-The seat is junk. I used duct tape banded around it to give me support, but this is far from a permanent solution. Should the tape snap, there is a metal bracket aimed at my spine waiting for me to fall onto it. I am going to have a mechanic I know bend me up an aluminum tube that will serve as both a seat and a roll-bar, and then use a hardened urethane foam contoured to my back and buttocks as the seat rest with holes drilled all over it to make it breathable.

-I have not been able to source replacement brake pads for my calipers. The calipers are in very usable shape, but I will need to swap them to change out my brake pads, which are thoroughly worn out.

That being said, the rear suspension works great enough to where at 20 mph or so, potholes are barely noticeable. I hope this translates to great usability at 30+ mph when I get the chance to try it.

I rode it to my office one day three weeks ago, and a co-worker took a picture of it:
Trike restored.jpg
Trike, 1-7-2016
Trike restored.jpg (135.59 KiB) Viewed 722 times
As you an see, not every piece of the trike was restored at that point. The old 90s era rear wheel with rotted tire and bent rear axle is still there, in contrast to my 20” Weinmann DM30 double-walled rims with Maxxis Hookworm 20”x1.75” tires up front. The restored frame(painted black) is contrasted with a seat and rear bracket that ultimately, are not going to be used, and where all of the drivetrain parts are rusted junk.

Two Saturdays ago, being my only opportunity to get to the nearest bicycle shop 8 miles away on the other end of town due to my work schedule, I decided to ride it there. Not having a car where I live(both of my cars are at my parents' house 1200 miles away as I do not have a valid license), riding it was my only option.

2 miles from the bike shop, the chain snapped. It didn't surprise me much given that it was junk along with the rest of the drivetrain, but I was still expecting it to at least get me to the bike shop, given that I had already ridden this thing perhaps 30 miles in total by now. I decided to lift the bike up by the rear bracket, and drag it with the front wheels on the ground for those 2 miles. I got to the bike shop 5 minutes too late as it was closed, and dragged it another 1.5 miles to a friends' garage to store it, as getting it home would have been a $50+ cab ride that I didn't want to pay for, nor did I want to spend the next 4 hours dragging a 50 lb trike back home.

Last Saturday, I got it to the bike shop. I have the following components on order:

-Shimano Tourney 165 mm mountain bike crank with 28T/38T/48T triple crankset
-Shimano freewheel, 7-speed with range of 32T-13T
-SRAM rear/front derailleurs
-26” rear wheel with 12 gauge spokes
-Schwalbe Marathon Plus 26”x1.75” tire
-Stretchproof 3/32” chain


The components are far from ideal, but they will get it rideable again and perhaps even reliable. Since my work schedule is going to be busy the next 2 weeks, I opted to pay the extra money to have the bike shop install the parts. I plan to ride it back home. First chance I get, I want to get started on a temporary coroplast body for experimentation purposes, as I would have done middle of last year had the trike not been through both a brawl and being run over.

After that, I will get a new seat and steering bars made and then I can begin work on a permanent body shell. I might share my design for the permanent shell here in the next two weeks or so.


With all of that being said, the gear ratios I have aren't good for my application. I chose a 7-speed freewheel due to the need for enough space to fit a sprocket and/or disk brake on the other side of the wheel in 135 mm dropouts, while able to accommodate a durable 3/32” chain. I couldn't find a quality 7-speed rear sprocket that had an 11T or smaller cog available, even though I had been planning all along to use one.

The 13T is the tallest ratio I was able to find for the rear sprocket that was quality built, and it will offer too low of a top speed. With the large 48T crank(the tallest ratio on any triple MTB crank I could find, but I was hoping I could find a 60T or something...), 13T in the rear with a 26”x1.75” tire gets me to 19 mph with a 60 rpm cadence, 26 mph at 80 rpm, 32 mph at 100 rpm, 39 mph at 120 rpm. The best I can hope for with this ratio is a comfortable cruising speed of 25-30 mph with a good body, and a top end of 40 mph.

I will definitely need a taller ratio, especially if I add an electric motor at a later date. I want a good range of cruising speeds between 25-40 mph with electric assist, and maybe 45-50 mph top end.

The 32T granny gear with the 28T ring gets me up a steep hill at 4.6 mph with a 60 rpm cadence. A 34T would be a bit better, but for the low end, this will do. I want to be able to pedal this thing up a hill if the battery is completely drained, while carrying 60 lbs of camping gear/clothes/tools.

Shimano used to make a 34T-11T 7-speed freewheel that would have been ideal for my application, but it is now impossible to find. I really badly want one. 11T would get me to 23 mph at 60 rpm, 31 mph at 80 rpm, 38 mph at 100 rpm, 46 mph at 120 rpm. This gives me the cruising speeds I want. 13T does not.

There is the DNP Epoch with an 11T-34T ratio, which is the perfect gearing for my needs, but the component seems to be too weak and unreliable for my application according to the reviews I have read. The smallest cog is probably going to see the most use out of any of them, considering this vehicle is being designed primarily for long trips at 30-35 mph, and considering my optimum cadence is between 80 rpm and 100 rpm. It needs to last, and it needs to be efficient.

I am at the limit of rear wheel/tire diameter that I can fit as well. I cannot get any bigger without running into clearance issues with the rear frame.

Any suggestions?

User avatar
amberwolf   100 GW

100 GW
Posts: 25122
Joined: Aug 17 2009 6:43am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: Critique this performance velomobile idea

Post by amberwolf » Feb 01 2016 2:27am

If you are willing to lose another couple percent of efficiency in the drivetrain, you can "move" the rear cluster to a jackshaft under the seat, just a pair of dropouts to hold a rear freehub with whatever set of cogs on the cassette (not a freewheel) you want, choosing the largest and smallest and in-between, out of whatever is available for your specific cassette-hub body.

Install one final sprocket bolted to the spoke flange of the hub just inboard of the largest cog on the freehub, which then drives the rear wheel's cog.

Then you can use another freehub to build the rear wheel from, and do the same thing there, and have as much gearing range as you could ever use, most likely. :)

Or use a strong singlespeed freewheel on the rear wheel, if you can get the range you want out of the freehub.



Regarding the brake pads...are they magnetic mount? If so, perhaps you could take the pads from some other type of brake, and cut/grind them into shape to fit your calipers.


That is some hard luck you've had with the trike...hopefully it's all gotten out of it's system now so you won't end up getting it folded around you when you are riding it, by some similar truck. ;)

User avatar
Chalo   100 GW

100 GW
Posts: 7154
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Critique this performance velomobile idea

Post by Chalo » Feb 01 2016 12:55pm

For very high gear ratios with reliable long term running in top gear, 11t is not your solution. The only reason 11t gearing works for pedal bikes is because it doesn't get used very much of the time. It wears out too fast, taking the chain with it, and it sacrifices efficiency.

I agree with Amberwolf that a jackshaft hub with step-up ratio is a better solution. You can use a disc hub with an output "sprotor" on the left, or you can use a tandem hub that has a freewheel thread on the left side for a drum brake (whose thread will also accept a single freewheel or fixed gear sprocket).

If you put a 22t freewheel on the hub's left side output, and a 16t sprocket on the left side of the rear wheel (you can use a track hub with LH threaded lockring for this, or another sprotor), and you use traditional full bushing chain with good chainline, you'll have a quiet, efficient, durable, reliable step-up stage that effectively makes a 14t rear sprocket into a 10.2t sprocket.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

User avatar
The Toecutter   1 kW

1 kW
Posts: 405
Joined: Feb 08 2015 4:02pm

Re: Critique this performance velomobile idea

Post by The Toecutter » Feb 03 2016 10:40pm

amberwolf wrote:If you are willing to lose another couple percent of efficiency in the drivetrain, you can "move" the rear cluster to a jackshaft under the seat, just a pair of dropouts to hold a rear freehub with whatever set of cogs on the cassette (not a freewheel) you want, choosing the largest and smallest and in-between, out of whatever is available for your specific cassette-hub body.

Install one final sprocket bolted to the spoke flange of the hub just inboard of the largest cog on the freehub, which then drives the rear wheel's cog.

Then you can use another freehub to build the rear wheel from, and do the same thing there, and have as much gearing range as you could ever use, most likely. :)

Or use a strong singlespeed freewheel on the rear wheel, if you can get the range you want out of the freehub.
Good idea, although I was hoping to avoid having to re-design the entire thing, as I was planning to place my battery pack under the seat to keep the CoG as low as possible, meaning the rider also has to be low and not far above the battery. Do you know of any commercially available kits for this that might work? I need to know their dimensions to see what needs to be changed to accommodate them.

I'm still planning on a 31" height to the top of the roof, so vertical real-estate is precious. I need a low frontal area.

A small percentage reduction in mechanical efficiency doesn't bother me much. The only time this would be bothersome is pedaling with no electric assist up a steep hill, and only mildly so. The aero advantages plus electric assist will reduce that loss to "noise" in most conditions, even if the numbers will add up over hundreds of miles of use.

I only have two shift knobs, so making a third set of gears adds more complexity than I would like given that I already have a front sprocket set and a rear freewheel that both have multiple speeds.
Regarding the brake pads...are they magnetic mount? If so, perhaps you could take the pads from some other type of brake, and cut/grind them into shape to fit your calipers.
They are not magnetic mount. The calipers should probably be replaced anyhow, due to age. When I motorize it later, going to hydraulic brakes will be a necessity... Know of any reliable, quality kits?
That is some hard luck you've had with the trike...hopefully it's all gotten out of it's system now so you won't end up getting it folded around you when you are riding it, by some similar truck. ;)
That will always be a possibility. I'm going to use LED strips on the body and a tall antenna with LEDs to improve visibility, with the capability to turn it off with one switch if desired.
Chalo wrote:For very high gear ratios with reliable long term running in top gear, 11t is not your solution. The only reason 11t gearing works for pedal bikes is because it doesn't get used very much of the time. It wears out too fast, taking the chain with it, and it sacrifices efficiency.

I agree with Amberwolf that a jackshaft hub with step-up ratio is a better solution. You can use a disc hub with an output "sprotor" on the left, or you can use a tandem hub that has a freewheel thread on the left side for a drum brake (whose thread will also accept a single freewheel or fixed gear sprocket).
I'm going to need to take a look at how that will fit together by looking at products. This idea seems to have been tried before and workable by others. A drum brake in the rear would also be useful for the inevitable panic stops that are going to arise during this vehicle's use.

I did a search for the term "sprotor" and found the following motorcycle kit:

http://www.lowbrowcustoms.com/drilled-s ... liper.html

Do you know of any bicycle equivalents?
If you put a 22t freewheel on the hub's left side output, and a 16t sprocket on the left side of the rear wheel (you can use a track hub with LH threaded lockring for this, or another sprotor), and you use traditional full bushing chain with good chainline, you'll have a quiet, efficient, durable, reliable step-up stage that effectively makes a 14t rear sprocket into a 10.2t sprocket.
With 10.2T I can get 24 mph with a 60 rpm cadence, 32 mph at 80 rpm, 40 mph at 100 rpm, 48 mph at 120 rpm. This ratio gives a comfortable cruising speed of 32-40 mph in top gear. This will suit a light draw of 200-400W from the battery nicely while the rider puts in 100-150W or so. Also important is this will yield a top end approaching 50 mph when the rider is sprinting with slightly over 120 cadence and making the most power while reducing the battery drain, although I doubt I could reach this without electric assist or the aid of a downhill.

However, I have a 13T rear sprocket. Even better, 16T/22T cogs would give me a 9.5T equivalent. This yields 26 mph with a 60 rpm cadence, 34 mph at 80 rpm, 43 mph at 100 rpm, 52 mph at 120 rpm. Imagine cruising at 45 mph! Technically, maintaining a 45 mph minimum would make it legal on the interstate in some places... That would be awesome!

The problem is that going to a 16/22 multiplier yields a hill climbing 28T front/32T rear granny gear speed of 6.8 mph at 60 rpm cadence. That would be a bit hard on the knees up a steep 15% grade if the battery were drained or the electric drive failed, and I really need the no-assist climbing capability at the low end. The best granny gear I can find is a 34T though, which won't make a huge difference versus the 32T I have. No more than 5.5 mph with 60 rpm cadence is about the right spot(would be sort of like power-walking up a steep hill in terms of effort).

A wider range freewheel would be nice. 34T-11T would have been perfect, with regard to freewheel speed range, but since reliable ones don't exist...

...maybe a 22/26 extra cog ratio would work decently. Would give me a 60 cadence in granny gear speed of 5.5 mph, and let me reach a top end of 46 mph at 120 cadence...

User avatar
Chalo   100 GW

100 GW
Posts: 7154
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Critique this performance velomobile idea

Post by Chalo » Feb 04 2016 4:03am

The Toecutter wrote:I did a search for the term "sprotor" and found the following motorcycle kit:

http://www.lowbrowcustoms.com/drilled-s ... liper.html

Do you know of any bicycle equivalents?
http://www.velosolo.co.uk/shopdisc.html
http://www.samagaga.com/Category.aspx?Category=Sprocket
http://www.jbi.bike/web/checking_produc ... mber=18007

In the bike world, a sprotor is a sprocket that mounts on a 44mm 6-bolt disc interface, but doesn't offer any disc brake function. Combining the two is a fool's errand anyway, because chains need lube and brakes need the absence of lube.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

User avatar
The Toecutter   1 kW

1 kW
Posts: 405
Joined: Feb 08 2015 4:02pm

Re: Critique this performance velomobile idea

Post by The Toecutter » Feb 04 2016 10:40pm

Thanks. This gives me a few options to consider.

As for the body, I've been studying the Milan SL trying to gather as much info as possible. I am considering copying its shape as much as is practical, but scaled to fit the dimensions of my trike. I doubt that I will get the 0.076 Cd the Milan has, but if I can get below a 0.20 Cd, I will be quite pleased. Other shapes of interest include the Cyclodyne(0.11 Cd), the Quest(0.2 Cd), the WAW, and the Strada.

The first coroplast shell will probably be a bit higher than 0.2 though, given the inability to make smooth compound curves with it, and just to have some type of shell at all quickly done up and usable, I will be keeping the complexity to a minimum with that. Perhaps it will be teardrop shaped when viewed from above, but a box when viewed from the side. Maybe a 0.35-0.4 is achievable with a weekend of work quickly fitting together a simple, temporary shell using coroplast. Maintaining laminar flow for an appreciable length of the vehicle is not easy to do with coroplast given its properties.

For the final permanent streamliner body to replace the coroplast one, dacron on wood, fiberglass and epoxy over foam, fiberglass/paper mache sandwich, all are viable candidates.

I was working on a foam shape for a fiberglass/epoxy shell last year, and had about 50 hours of work in it before it was destroyed...

User avatar
The Toecutter   1 kW

1 kW
Posts: 405
Joined: Feb 08 2015 4:02pm

Re: Critique this performance velomobile idea

Post by The Toecutter » Feb 14 2016 12:23am

The trike is not back in my possession yet, as that Schwalbe Marathon tire has proven hard to obtain for the bike shop. It should be in on Wednesday.

I look forward to testing some top speed(s) with various faring designs.

User avatar
The Toecutter   1 kW

1 kW
Posts: 405
Joined: Feb 08 2015 4:02pm

Re: Critique this performance velomobile idea

Post by The Toecutter » Feb 21 2016 1:19am

I retrieved the trike today and rode it 8 miles back home. I had just one opportunity to get a ride over to the bike shop in the early morning, and took it, thus requiring me to ride back on an empty stomach, so I didn't push myself very hard, but I probably averaged about 12 mph, and topped out at about 25 mph, judging from my selected gears and cadences.

The rear suspension is awesome and made it worth investing into this particular trike. A new suspension trike can run well over $2,500, and I've got just under $1,500 into this one. In 2 years of searching, I found plenty of trikes for $1,500 or less in better shape on the used market(some as low as $600), but not one of them was suspended. One enticing potential purchase was for a $1,600 trike in Austin, manufactured out of carbon fiber, weighing only 25 lbs, but the lack of a rear suspension destroys its viability for hitting uneven patches of pavement at higher speeds. I like how well the rear suspension on my Thunderbolt dampens all of the bumps and curves. This unexpectedly and thankfully has the potential of feeling somewhat La-Z-Boy-like without any further weight penalty, if I can do something about this seat.

The seat still leaves much to be desired. An immediate improvement to be made would be to obtain some nylon webbing and make a high-tension overlapped criss-cross pattern in the manner of a lawn chair. It currently doesn't feel safe hauling ass down the street at 25 mph over uneven pavement with bands of duct-tape being the only thing holding me up over an unpadded piece of steel frame aimed at my spine! A good, stiff space to rest my back on that has enough elasticity to absorb excessive road harmonics while keeping my back protected is the minimum that I need. I may not have to have a new seat frame bent, but it may be done anyway for the sake of ergonomics and/or reducing frontal area.

The front derailleur replacement didn't fit, so the old one is still in use, but it is worn out/damaged, and as a result, only the larger two sprockets are available and the granny sprocket had to be locked out from the gear selector. I need to replace this derailleur to be able to use my granny gear sprocket. Going uphill as isn't too bad, but I haven't had to contend with more than a 10% grade, either, or start stopped at the bottom of the hill.

I finally got a chance to weigh this heavy trike in working condition. It's 77 lbs. There's about 5 lbs or so that can be stripped from it with ease, but anything more is going to get practically impossible. I won't have a lot of room to work with for my body, motor, controller, charger, and battery.

I'm going to likely order a Tangent Motors “The Ascent” as it is very light and powerful, at about 7 lbs for 4 kW peak mechanical power. Included in this low weight is a controller, motor, Cycle Analyst, and mounting. This setup is pricey at $1,800, and I would have to swap out my 3-speed mountain crank for a single-speed sprocket. 44T would probably be the best compromise, and I would settle for a top gear speed of 42 mph at 140 cadence(“The Ascent” only allows up to 140 cadence), 36 mph at 120 cadence, 30 mph at 100 cadence, 23 mph at 80 cadence, no jackshaft needed. Going uphills with no assist would yield 7.2 mph at 60 rpm cadence, difficult for 15%+ grades, but otherwise usable, roughly matching my big rear sprocket with the middle front crank. As long as the battery has charge and the electric motor still functions, no hill will be an issue, but without, anything steeper than 10% could become a problem.

I am now thinking about a small but power-dense battery of about 10 lbs and perhaps 500 Wh usable capacity, instead of having a heavy 25 lb LiFePO4 battery. 500 Wh could still give me 75+ miles range at 30 mph with me pedaling at 100W and the motor drawing another 200W from the battery if I come in with a CdA of roughly 0.12 m^2. All I need to do is get a good, accurate, programmable fast charger with BMS so I can charge them in under 20 minutes from a standard 110V outlet, or alternatively and more expensive, carry two spare packs and make them swappable. I need 5 kW peak from the battery to max out the capabilities of the “The Ascent”, but that's a tall order for the cheap Chinese LiFePO4 available. Real A123 pouch cells don't seem available. Too bad the Hobby King/Turnigy Li Poly batteries are toxic grenades, because their peak power, specific capacity, and price are otherwise decent, but I'd rather not catch my ass on fire accelerating to 40 mph at full throttle when these things decide they want to commit suicide by self-immolation... Those 100C Lonestar cells used in the Zombie 222 and in one of Doctorbass' Zero look enticing, and would run very cool with regard to operating temperature considering they are 0.0006 Ohms at ambient and 0.0003 Ohms warmed up. 18S2P would give me ~620Wh, or ~500Wh to 80% DoD, ~65V under load, and weigh in at 10 lbs, and 5 kW electrically would be roughly 15% of their capabilities, and would only cost $720.

I assume that rear torque arms, seat reinforcements, wiring, charger, and all that stuff will equal out to about 3 lbs.

This would leave 8 lbs for my body and storage area. Possibly doable, if I go with a design that doesn't enclose the whole vehicle in one giant teardrop, but instead build a small, light, narrow teardrop for the rider, and a separate 2 teardrops for the front wheels. A Cd of 0.3 and a frontal area of 0.4 m^2 would do the trick... and doesn't seem all that implausible considering that the 1921 Rumpler Tropfenwagen has a 0.28 Cd having a similar shape to what I am describing but without the advantage of covered wheels. Dacron on wood frame is looking more appealing, but alternatives could also include foam, mylar, paper mache with some kind of adhesive, or hardened fabric over a wire frame. Imagine a sort of cross between the Rumpler Tropfenwagen and the Birk Butterfly, and you will get a picture of what I have in mind. Better than a 0.12 m^2 drag area may be possible.

This low weight/low area body will necessitate new steering bars, probably ones that are attached to a pole that sits between my legs with the handlebars being with my hands positioned up-right and horizontal behind my knees.

This is shaping up to be a $4,500 project. This heavy steel trike won't allow me to meet all of my goals, but it will serve as an excellent testing platform. It won't be my last build. I think it will be well worth the expense, as the parts can be transferred to something else that I build later.

I'm definitely going to want something lighter, narrower, and with a full front/rear suspension and larger diameter rear wheel in the long term, and the only way I'm going to get that at an affordable price is to build it myself from scratch with square-shaped aluminum tubing, a welder, and some light motorcycle parts. Approaching the efficiency of the Milan SL and fitting in a 30+ lb battery pack, with gearing for 70+ mph top end, would be the overall idea.

User avatar
amberwolf   100 GW

100 GW
Posts: 25122
Joined: Aug 17 2009 6:43am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: Critique this performance velomobile idea

Post by amberwolf » Feb 21 2016 2:08am

The Toecutter wrote:The seat still leaves much to be desired. An immediate improvement to be made would be to obtain some nylon webbing and make a high-tension overlapped criss-cross pattern in the manner of a lawn chair.
YOu can also use nylon "webbing" meant for overhead canopy stuff; that's what my CrazyBIke2 seat was made of originally, with holes melted thru it's doubled-up edges so I could lace the back together with paracord to tension it.

Presently it is made of the nylon base "sheet" that was on a sleeper couch (the part suspended by it's edges with springs that holds up the mattress), with holes at the edges for lacing, though this time I used a harbor-freight reinforcement-ring eyelet "kit" where you hammer a ttol thru the material to make the hole, then the other part of the tool to close the eyelets thru the material to reinforce the hole. Then again it's laced with paracord across the back to tension it, in a pattern like that on a shoe's string over it's tongue.

Real A123 pouch cells don't seem available.
[/quote]
They are, AFAIK, available from at least two places, officially stuff from A123 itself,
http://www.a123batteries.com/product-p/amp20m1hd-a.htm
https://www.buya123products.com/goodsdetail.php?i=8
specs
http://www.a123systems.com/prismatic-cell-amp20.htm
though I don't know the MOQ; the first is USA AFAIK so since you're also in the USA there's no worries dealing with customs, just ground shipping. dunno about the second place; it's listed as in China but that's also where A123 makes some stuff now, based on info in other A123 threads.

16s fits well in a 50cal ammocan, but it's heavy, nearly 25lbs IIRC, maybe more. Fully charged at ~58v for "48v" nominal. Mine came from EM3EV, though indirectly, as a used back bought from another ES member, and is aging, so I'm sure you'll get better performance from the new cells A123 sells.


If you can find some, the EIG NMC 20Ah pouches work well; I use them (and/or the A123) at peaks of 2.5-4kw depending on which one they're on (CB2 or SBC), but you'll have a nearly-20lb battery once assembled with case and all, for 14s ("48v" nominal, ~58v full). Does fit real nice in a 50cal ammocan, though. (18s would fit, too, IIRC).

Another option, if you don't mind building it, is 18650 cells. There's a number of ways to build packs out of new cells easily enough (lots of threads on that sort of thing, which cells are better, etc; havent' tried it yet myself), or you can buy premade packs from reputable USA vendors.

Post Reply