Building a velomobile

[flangefrog]

Hi guys, a little introduction: I am 20 years old, I live in the outer suburbs of Auckland, New Zealand (any other Kiwis here?). I have a lot of hobbies - photography/cinematography, programming, electronics, web design, computer building etc. Probably the best way to see them is on my LinkedIn profile.

I want a bike that can go fairly long range (it's over 23km to the city centre), it also needs to go in any weather and be fairly good at hills. I'm not that worried about speed, I can go about 16 to 25kph average on my bike but I can go faster on my brother's aluminium hardtail. If I can go 25kph with no pedal assist on my velomobile that would be nice although I do plan to pedal as well. It will be for both commuting and touring so I would like to have space for two backpacks (one with my camera gear and laptop) and space for my rather large tripod. I have a 500km trip which I would really like to do sometime. Most of it is fairly flat but near the end is a 150km trip over a mountain range which depending what route I choose may have grades up to 40% and a total of 3400m elevation gain over a gravel road. I want to take this into account when building the velomobile.

I've decided to go with a recumbent tadpole trike and have bought a few plans, I think I will go with Atomic Zombie's Warrior but may use the rear suspension from my current bike like the StreetFox design.
I have a cheap full suspension bike I bought at least 5 years ago, the frame looks similar to this but the bike is steel apart from the rims. It also only has V brakes. I also bought a few more hardtail frames for $10 to use for parts. I'm not sure which joining method I will use, I was thinking of brazing or mig welding, any input on which one is easier or better for this purpose? I've never done any welding or brazing before.

The laws in New Zealand state that a class AB (Power-assisted pedal cycle) vehicle is "A pedal cycle to which is attached one or more auxiliary propulsion motors having a combined maximum power output not exceeding 300 watts." Do you guys think this would be enough to get me up a 30 or 40% grade on a mid drive system? According to this website it seems that even a 300W hub motor can. The motor I have been looking at is a GNG mid drive or side drive system, side drive seems a lot cheaper and since I want to use an internally geared hub such as the NuVinci (I've applied for a N171 dev kit) I can't see any downsides over a mid drive system? Also because they don't have a 300W motor available I have the option of overpowering a smaller motor or underpowering a large motor, I guess that underpowering a large motor would be the best as that would give me more torque but slower speeds? The main factor deciding the voltage I will use is probably going to be the price. Edit: so I read the 300W is probably measured at the wheel (not that anybody would ever measure it), so a GNG 350W kit might be the way to go. I still need to decide on the voltage (I'm thinking 36V) and whether to use the mid drive or side drive kit.

Here's a list of the main components I am thinking of buying The definite items are highlighted in green.

Any comments or suggestions? I'm particularly looking for help as to which motor to buy.

 

[bowlofsalad]

I've decided to go with a recumbent tadpole trike and have bought a few plans, I think I will go with Atomic Zombie's Warrior but may use the rear suspension from my current bike like the StreetFox design.
I have a cheap full suspension bike I bought at least 5 years ago, the frame looks similar to this but the bike is steel apart from the rims. It also only has V brakes. I also bought a few more hardtail frames for $10 to use for parts. I'm not sure which joining method I will use, I was thinking of brazing or mig welding, any input on which one is easier or better for this purpose? I've never done any welding or brazing before.

I don't know if you've read any of the atomiczombie plans, but their frames are not designed from brazing. I am not sure if you mean MIG (GMAW) or flux core (FCAW), there is a difference. Either way, mig is an excellent form of welding and it's what I'd probably aim for. Atomiczombie plans suggest using stick welding, probably because it's really cheap, I think.

The laws in New Zealand state that a class AB (Power-assisted pedal cycle) vehicle is "A pedal cycle to which is attached one or more auxiliary propulsion motors having a combined maximum power output not exceeding 300 watts." Do you guys think this would be enough to get me up a 30 or 40% grade on a mid drive system? According to this website it seems that even a 300W hub motor can. The motor I have been looking at is a GNG mid drive or side drive system, side drive seems a lot cheaper and since I want to use an internally geared hub such as the NuVinci (I've applied for a N171 dev kit) I can't see any downsides over a mid drive system? Also because they don't have a 300W motor available I have the option of overpowering a smaller motor or underpowering a large motor, I guess that underpowering a large motor would be the best as that would give me more torque but slower speeds? The main factor deciding the voltage I will use is probably going to be the price. Edit: so I read the 300W is probably measured at the wheel (not that anybody would ever measure it), so a GNG 350W kit might be the way to go. I still need to decide on the voltage (I'm thinking 36V) and whether to use the mid drive or side drive kit.

I am pretty sure you couldn't climb a 40% grade on 300w alone, but I've never used a mid drive. Maybe with the right gear ratio and lots of pedaling. I love the idea of a velomobile, but here is the issue I imagine. A trike will weigh more than a bike, a etrike will weigh even more, a DIY etrike will weigh even more, and a DIY etrike velomobile will weigh even more. Your bike isn't going to be very light weight. I love the idea of a velomobile. But your setup is probably going to be very heavy. The heavier things are, the more energy they take to climb a hill. Personally, I wouldn't worry so much about those draconian ebike laws, especially if you are making a velomobile. I imagine it'd be really hard for even someone who has ebikes to tell you have a motor.

Deciding on which components to buy is a difficult thing to do, the information is scarce, passing knowledge and experience on about this is difficult to impossible for your or anyone's specific situation (A guy on a light upright ebike using a mid drive probably can't give you advice on a motor that would work well for your situation), and it's really hard to know anything without first hand experience. When talking about climbing very steep hills, mid drives and geared are often mentioned. You'd probably need dual geared drives, but I fear you might burn them out on that setup climbing up long 40% grades. So maybe your best bet is a mid drive, I don't really know. But if you are climbing huge steep hills, be prepared to pedal and consider including a temperature probe or two with a cycleanalyst version 3 (CAv3).

You didn't really mention anything about the velomobile design or how you intend to build it.

 

[parajared]

Atomic zombie is building a velomobile too. He has pretty neat, cost effective way of doing it. Here's the link to his build (it's free) http://www.atomiczombie.com/Tutorial%20-%20Building%20a%20VeloMobile%20-%20Page%201.aspx

I personally think it would be pretty neat to do a more comfortable, more manaueverable version of the human powered vehicle racers. These guys are hitting 80mph under just their own leg power.

I have a KMX Typhoon tadpole trike and no suspension isn't that bad at all. The biggest discomfort for me is belly fat jiggling around . I find no suspension two wheel upright bicycles to be close to unbearable, but I also have a spinal injury.

I am building a tadpole trike for my wife, and it's actually not been that hard to build the frame. The hold up for me is making the front wheels work. Atomic zombie's guide calls for just using BMX wheels with pretty stout hubs, but after looking at some of these "stout" hubs I feel pretty skeptical about this method. I want to build my trike like my KMX; a grade 3 rod through a set of bearings, but the best deal I have found on trike wheels are $120 per wheel at Utahtrikes.com. This is a bit above my buget.

I am not sure if you mean MIG (GMAW) or flux core (FCAW), there is a difference. Either way, mig is an excellent form of welding and it's what I'd probably aim for.

MIG welders offer a lot of bang for the buck. I bought one off Craigslist for $100 and it has been well worth it. If you ever have anything metal break, now you have a tool to "glue" it back together. I highly recommend getting a self darkening mask (one where you can see through initially, but as soon as you weld it darkens). These masks are lightyears ahead of the whole futz around in the dark setup that plauge the lives of newb welders.

 

[flangefrog]

I don't know if you've read any of the atomiczombie plans, but their frames are not designed from brazing. I am not sure if you mean MIG (GMAW) or flux core (FCAW), there is a difference. Either way, mig is an excellent form of welding and it's what I'd probably aim for. Atomiczombie plans suggest using stick welding, probably because it's really cheap, I think.

Yeah I have some of his plans and although I knew he suggested arc welding I didn't know they weren't for brazing (why is that?). I meant GMAW, I also have arc welders available but from everything I've read mig is easier and better. Only problem is gas is very expensive here.

I am pretty sure you couldn't climb a 40% grade on 300w alone, but I've never used a mid drive. Maybe with the right gear ratio and lots of pedaling. I love the idea of a velomobile, but here is the issue I imagine. A trike will weigh more than a bike, a etrike will weigh even more, a DIY etrike will weigh even more, and a DIY etrike velomobile will weigh even more. Your bike isn't going to be very light weight. I love the idea of a velomobile. But your setup is probably going to be very heavy. The heavier things are, the more energy they take to climb a hill. Personally, I wouldn't worry so much about those draconian ebike laws, especially if you are making a velomobile. I imagine it'd be really hard for even someone who has ebikes to tell you have a motor.

I think the 40% grade is only a very small section, most of the climbs are around 20% to 30% max, here are a couple of pics showing the last two legs over the mountain range:
http://imgur.com/9y5FV3r,CXtopMo#0
http://imgur.com/9y5FV3r,CXtopMo#1
There is also the option to do it in one day on the sealed road (different route) but I'm not really sure if I could get that much range.

Deciding on which components to buy is a difficult thing to do, the information is scarce, passing knowledge and experience on about this is difficult to impossible for your or anyone's specific situation (A guy on a light upright ebike using a mid drive probably can't give you advice on a motor that would work well for your situation), and it's really hard to know anything without first hand experience. When talking about climbing very steep hills, mid drives and geared are often mentioned. You'd probably need dual geared drives, but I fear you might burn them out on that setup climbing up long 40% grades. So maybe your best bet is a mid drive, I don't really know. But if you are climbing huge steep hills, be prepared to pedal and consider including a temperature probe or two with a cycleanalyst version 3 (CAv3).

By dual geared do you mean another Derailleur?

You didn't really mention anything about the velomobile design or how you intend to build it.

Yeah I'm still looking at the fairing designs. This one, this one and this one looked pretty cool. I found a pretty cool guide on making a bubble here, and it's also a very cool design, sort of like the Evo R. The second one should be able to fit enough stuff inside for touring if the back was extended a little. I think I'm going to work on the trike first and then decide what fairing and the material.

Atomic zombie is building a velomobile too. He has pretty neat, cost effective way of doing it. Here's the link to his build (it's free) http://www.atomiczombie.com/Tutorial%20-%20Building%20a%20VeloMobile%20-%20Page%201.aspx

I looked at his but I didn't really like the design. I like the tadpole trikes better as well.

I personally think it would be pretty neat to do a more comfortable, more manaueverable version of the human powered vehicle racers. These guys are hitting 80mph under just their own leg power.

They are cool but I don't think they are very practical for lots of stopping or hill climbing etc as well as carrying lots of stuff.

I have a KMX Typhoon tadpole trike and no suspension isn't that bad at all. The biggest discomfort for me is belly fat jiggling around . I find no suspension two wheel upright bicycles to be close to unbearable, but I also have a spinal injury.

The main reason I was thinking of rear suspension is that I want to use the rear part of a frame anyway so I may as well add the spring.

I am building a tadpole trike for my wife, and it's actually not been that hard to build the frame. The hold up for me is making the front wheels work. Atomic zombie's guide calls for just using BMX wheels with pretty stout hubs, but after looking at some of these "stout" hubs I feel pretty skeptical about this method. I want to build my trike like my KMX; a grade 3 rod through a set of bearings, but the best deal I have found on trike wheels are $120 per wheel at Utahtrikes.com. This is a bit above my buget.

In his plans for the Warrior he decided to go with 20mm hubs instead because they can take disc brakes, I am thinking of either using those or 15mm hubs. A lot of trikes seem to use even 12mm hubs with sturmey archer hubs and apparently are fine.

MIG welders offer a lot of bang for the buck. I bought one off Craigslist for $100 and it has been well worth it. If you ever have anything metal break, now you have a tool to "glue" it back together. I highly recommend getting a self darkening mask (one where you can see through initially, but as soon as you weld it darkens). These masks are lightyears ahead of the whole futz around in the dark setup that plauge the lives of newb welders.

I'm pretty sure we have one of those, my dad/uncle/grandpa have welding equipment so I've basically got arc, gmaw mig and oxy acetylene to choose from.

 

[dogman dan]

Man, I knew NZ has the steep, but 30-40% grades are pretty extreme for paved stuff. Mid drive is the way to go for that, and gear down to tackle stuff that steep at sub 20 kph, but keeping the motor rpm up.

I would worry less about the actual wattage level than about the speed. If you are geared for 25kph, then you won't attract a lot of attention. Go ahead and sneak 1000w. It's when you haul ass that cops notice you. But going 25kph, you won't often use more than 200w. Only when you start to climb will you use more.

Get some legit looking markings for your motor and controller, you know, 200w stickers.

 

[flangefrog]

Man, I knew NZ has the steep, but 30-40% grades are pretty extreme for paved stuff. Mid drive is the way to go for that, and gear down to tackle stuff that steep at sub 20 kph, but keeping the motor rpm up.

I would worry less about the actual wattage level than about the speed. If you are geared for 25kph, then you won't attract a lot of attention. Go ahead and sneak 1000w. It's when you haul ass that cops notice you. But going 25kph, you won't often use more than 200w. Only when you start to climb will you use more.

Get some legit looking markings for your motor and controller, you know, 200w stickers.

The 30%-40% grades were on the unpaved road, see the video here: http://www.motutrails.co.nz/. Actually I think it is 50% max grade at least according to Google. The paved road only had about 20% max grade or something but I think I would have to do 140kms in one go as it doesn't go past the farmstay. Also it still climbs just as much, the grades are just averaged out more. I'm not too worried about sticking to the rules but it's also about cost and efficiency/range. BTW NZTA (New Zealand Transport Association) doesn't mention anything about speed limits on an ebike here but that is of course more dangerous than more torque

If I didn't end up going with the GNG motor or wanted a more powerful one the cyclone also looked good but it is of course more expensive.

I'm fine if it's slow up hills, even 5-10kph.

 

[flangefrog]

I've been looking at more options for a motor system and I found the goldenmotor 800W BLDC which has been used in LI-ghtcycle's bike. So far this is looking like the best option, especially since I will also be using a NuVinci N171B and can use a single stage reduction geared for around 7-25kph (I think LI-ghtcycle's was geared for around 11.5 to 40kph). It should also be fairly cheap since apart from the motor and controller I would just need a large rear sprocket and maybe a bigger motor sprocket. One of those would also need to be a freewheel if I don't want the motor to turn while pedaling.

I have been quoted a price for the NuVinci dev kit: $471.52 USD which includes $305.53 of shipping costs... I read in another thread here that someone was only quoted $150 shipping and got it down to $115 with surface shipping so I've asked FallBrook about that.

 

[ddk]

suddenly out of no where
-my opinions

I read the zombie thing
Personally, I think his opinions are his opinions. I have both body materials he compared. 3mm luan plywood and 4mm Coroplast ...and the my plywood is definitely heavier than the plastic cardboard.
As for other people building Coroplast bodies with lots of struts:
It is my belief that these people chose to use lots of struts for no real reason I can think of. I support Coroplast hardly at all and it holds its' shape just fine.

facts:
you're not building a boat
you're not building an airplane
-You're building a lightweight body structure to keep you and your stuff dry.
Aerodynamic bodies look really nice. That's about all they're worth for a low speed vehicle...
There are other materials besides plastic cardboard and luan plywood. See what's available locally first.
Always remember you're building a powered-vehicle. Not a pedal bike. Weight matters, but not as much as power available to move the beast.

Real problems to solve:
-visibility. On an open bike/trike this isn't an unsolvable problem. Some velos I've seen have very limited visibility, which IS a problem.
-getting on and off (or in and out) You can probably still contort your body into weird shapes. I can't.

I don't hold a high opinion of the NV 191
Mine gave me all sorts of fits until I reduced the torque from "me"

I use hub motors as mid-drive motors because of their lower KV. Gearing ratios can be lots lower.

Good luck with your build...

 

[bowlofsalad]

I know nothing of the visibility, but I've seen velomobile designs with a raising/lower shell attached to a hinge. http://diyvelomobile.blogspot.com/

Define low speed? I find it puzzling that anyone would argue the value of aerodynamics. At 20mph, aerodynamics is a big deal, and assuming you go any faster it only becomes more important. Something a lot of people don't really fully realize is, on a windy day, even traveling at 10 mph can be like traveling 30+mph, cutting through the wind with higher drag versus lower drag is a massively huge deal. Cruising at 30mph on an ebike with an upright compared to a velomobile is grossly different in how much energy will be used in various situations.

Velomobiles are more than just fancy ways to keep you and your junk dry.

 

[Geebee]

ddk, one issue with your opinions, the low speed aerodynamic bodies add a truck load of extra speed even with pedaling as the only power source.
My shells would allow me to cruise at 45 kph as opposed to 30ish on the flat with my trike, wind had little effect.
Corflute/ coroplast allows a stupidly light shell with a partial internal frame, I weighed my first shell when removed at it was roughly 3kg complete including the frame, it's the one in my avatar.
Below is the second one.

 

[ddk]

ddk, one issue with your opinions, the low speed aerodynamic bodies add a truck load of extra speed even with pedaling as the only power source.
My shells would allow me to cruise at 45 kph as opposed to 30ish on the flat with my trike, wind had little effect.
Corflute/ coroplast allows a stupidly light shell with a partial internal frame, I weighed my first shell when removed at it was roughly 3kg complete including the frame, it's the one in my avatar.
Below is the second one.

nice body... not exactly super aerodynamic.
I'm referring to those ultracurved, impossible-for-normal-humans-to-fabricate bodies

I agree:
I think Cor-whatever (plastic cardboard) is great material to work with for bicycle stuff including diy velobodies! I think your attempts are pretty darned nice.
I also think plywood is great... for car trailers.... and sub-flooring

@velobodies for increased speed:
I have an open semi-recumbent trike I use in good weather. It's swell and goes as fast as I wanna go (which isn't that fast)
But when the local weather consists of rain, fog or dark* (or all three) , I use my enclosed trike. My enclosed trike doesn't go fast. By design.
My rational (and experience) for not traveling fast in a rainstorm is simple: reduced splash from the trike's tires (tyres).
With that in mind, I limited the top speed of my enclosed trike to 15mph.
So:
I normally ride @ 10mph in moderate rain and if the wind and rain is especially heavy I go as slow as 5mph... and stay dry.
The body is fashioned from mild steel square tubing, covered mainly in (heavy) polycarbonate plastic and a (very light) coroplast roof. Visibility is not a problem. The body adds 50 kg (!) to the trike
Amazingly ( by design or luck) my enclosed trike is hardly affected by wind
yep- pretty goofy looking
aerodynamics and high wind loads are always a concern. And should be.
For the average DIYer , a smaller face presented to the wind is always the best approach for reducing pressures on the vehicle. Except It's not the only approach
-is all I'm suggesting

*a night-time event, usually

 

[flangefrog]

Well this is the fairing I like most (apart from carbon fibre and fibreglass):

I think it could be built from either coroplast or plywood, if it had a frame then I could do the whole thing out of lexan or some other plastic material. Maybe I'm dreaming here but I could even make each side open gullwing style like a DeLorean:

It's a bit higher than most velomobiles as it's fully faired and at night it would easily be seen as I would have bright front and rear lights as well as lights along the horizontal seams. I would need to make sure it had enough space for all my stuff, maybe I could make some space between the rear wheel and the seat in addition to using the top and sides of the wheel.

Here's a quick estimate of how much this thing's probably going to weigh, I don't think plywood vs coroplast will really make a big difference. I think I'd prefer to work with plywood and make it really solid but I'm open to using coroplast or other materials on it. The fairing weight is based on a steel frame/rollcage (maybe not needed) and plywood but would probably be less than that.

20kg frame
15kg fairing
40kg batteries
10kg motor
55kg me
30kg luggage
____________
170kg total

 

[The Stig]

I have a 500km trip which I would really like to do sometime.

New Zealand! Have you seen the episode of top gear that aired last sunday?? Click on the number 3 in the middle left of video box to go straight to that segment of the episode: http://www.streetfire.net/video/top-gear-season-20-episode-1-20x01_2430592.htm


Wow 48V 40AH battery for $750, where did you find that deal?

 

[flangefrog]

Don't have a TV (and it probably won't air in NZ for at least a few weeks) but just watched it now

The battery is a vpower one, maybe not the best quality though: http://vpower.hk/product.php?id=28 (my price was from here: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290936641772)
I'd actually like to go for one of these as there's a place in NZ that did a group buy a while ago and hopefully will again. They are even cheaper than the vpower batteries at around $1.60 NZD per AH. 12 100A cells would be nice for 4.44kWh.

 

[bzhwindtalker]

Hey! I built a coroplast velomobile two years ago and rode across the usa with it, it was a lot of fun!
have a look at the pictures here :
http://electricgarage.weebly.com/veacutelomobile-de-voyage.html
Here's a video of someone we met shot!
https://vimeo.com/25800618

Also, you should join the velomobiles-coroplast group on FB, good info there.
300w should be plenty to go fast on a velomobile if you pedal without cheating
We had no motor in our velos and we averaged 20mph on century rides on flat.

Good luck!

 

[flangefrog]

Cool, yeah I've been looking at some of the coroplast fairings on facebook.

The purpose of the motor is not really to get me going fast, but to help up hills such as this one (most are not quite this steep though, it looks like maybe 50% grade to me?) and increase my range. From reading about other bikes it seems I'll need around 1000W or so depending on the gearing.

 

[ddk]

my open trike can climb hills like that. I don't even help.
It uses two motors: a geared front geared-hub motor (mighty mite MAC w/23A controller) in a 24" wheel and a geared-hub motor driving the input NV191 hub in a mid-mount position (Bafang w/30A controller) I run the motors with individual 40V 20Ah LiCo batteries. 10S4P 20C (8 each 5S 5000ma 20C)
48V batteries would be better but either/or, expect to expend a lot of energy climbing hills like that...
40V keeps my top speed via 'motors only' locally legal
I normally carry 40Ah of battery but can easily carry 90Ah
My enclosed trike might be able to climb those grades, but I've only taken it up a 22% grade(effortless). It's front has the same motor only mounted in a 16" wheel, which is a really strong combination. (I'm unsure of the rear motor's capability)
**************************************************

Polycarbonate (Lexan) is pretty heavy material. My enclosed trike is covered in various thicknesses of it.
Lexan is easy to shape and can be cold-bent. I much prefer working with it over acrylics. Cost locally is about the same

The advantages of coroplast over plywood is:
-it actually is waterproof
-no finishing (no need to paint it) Comes in several colors
-can be cut with anything. I even use my turkey-carving electric knife (used for foam, mainly)
-where I live, fabric bodies would be a mistake. Not everyplace is the same. (sudden wind bursts up to 100mph rarely; 50mph often locally)

but I'm just making suggestions to help you avoid what may become costly mistakes.
I suppose if you like to paint and have a place to do it, plywood would be ok, but in my unintended crash tests* with stuff made from plywood and coroplast, plywood suffered the most damage always
-keep on keeping on-

*avoiding contact with BIGGER vehicles like trucks and SUVs meant having to dump the trike. Nowadays I ride much slower @ 20 mph or less

 

[flangefrog]

my open trike can climb hills like that. I don't even help.
It uses two motors: a geared front geared-hub motor (mighty mite MAC w/23A controller) in a 24" wheel and a geared-hub motor driving the input NV191 hub in a mid-mount position (Bafang w/30A controller) I run the motors with individual 40V 20Ah LiCo batteries. 10S4P 20C (8 each 5S 5000ma 20C)
48V batteries would be better but either/or, expect to expend a lot of energy climbing hills like that...
40V keeps my top speed via 'motors only' locally legal
I normally carry 40Ah of battery but can easily carry 90Ah
My enclosed trike might be able to climb those grades, but I've only taken it up a 22% grade(effortless). It's front has the same motor only mounted in a 16" wheel, which is a really strong combination. (I'm unsure of the rear motor's capability)

How many watts is the MAC motor? I saw your build thread for that trike, did you feel the NuVinci (do you mean the 171B?) didn't have enough range by itself?
Could you run the motors indefinitely without overheating for example on a 3 hour climb?

Polycarbonate (Lexan) is pretty heavy material. My enclosed trike is covered in various thicknesses of it.
Lexan is easy to shape and can be cold-bent. I much prefer working with it over acrylics. Cost locally is about the same

Does cold-bent mean it is not rigid and can be bent over a frame? I don't think I would need to use nearly as much as you had as the fairing is smaller and only the windows would be clear.

The advantages of coroplast over plywood is:
-it actually is waterproof
-no finishing (no need to paint it) Comes in several colors
-can be cut with anything. I even use my turkey-carving electric knife (used for foam, mainly)
-where I live, fabric bodies would be a mistake. Not everyplace is the same. (sudden wind bursts up to 100mph rarely; 50mph often locally)

I am fine with painting the plywood, I also have access to a fair amount of tools and machinery. I would't be surprised if there is already some plywood here that I can use. So for me personally the main reason to go with coroplast is the weight. I'm still on the wall about it though. Here's a velomobile made solely of plywood and amazingly only weights about 20kg, one wheel mount did break though with too much stress.

I suppose if you like to paint and have a place to do it, plywood would be ok, but in my unintended crash tests* with stuff made from plywood and coroplast, plywood suffered the most damage always

What sort of damge? As in the plywood shell being crushed? If I had a light steel frame (i.e. thin metal rods) it should stop either coroplast or plywood from being crushed at only a very small weight penalty.

 

[ddk]

How many watts is the MAC motor? I saw your build thread for that trike, did you feel the NuVinci (do you mean the 171B?) didn't have enough range by itself?
Could you run the motors indefinitely without overheating for example on a 3 hour climb?

#1 350W rated- I run as much as 23A -or- ~900W
#2 The 171 (I use the other to avoid searches because mine sux) It has plenty of range. If I apply too much torque to one side of the NV, it's body warps and it shifts itself into it's highest gear. This is not good when you're struggling up a hill (pedaling hard). #3 The longest hill I've climbed was 7 miles @ a max of 11% grade. The motors were at normal temps the whole time. Going down the other side cooled off everything (except the brakes -lol)
I don't use my trikes off-road very often or very far.
The driveway to a house I visit has a 100M 30% grade that does a little 'bump' of 35% for 9M. Most of the hills around here (mountains) are between 4-15% grades.

When you get down to it, you really only need two speeds on an e-bike
1-low gear for the steepest hill
2- everything else

Does cold-bent mean it is not rigid and can be bent over a frame? I don't think I would need to use nearly as much as you had as the fairing is smaller and only the windows would be clear.

Depends on the thickness as to how easily it can be cold-shaped around struts. 3/32" is pretty darn flexible.
Cold -bent means you can bend it permanently into a shape using a brake. Limitations of the bend is subject to the thickness. I've bent 6.3mm polycarbonate to 100 degrees and 90 degrees. Thinner material should bend farther, but I haven't had the occasion to do so.

What sort of damge? As in the plywood shell being crushed? If I had a light steel frame (i.e. thin metal rods) it should stop either coroplast or plywood from being crushed at only a very small weight penalty.

Steel is the easiest to work with for struts etc. (my opinion)
It's weight is on par with fiberglass struts except it doesn't bend like fiberglass or pvc pipe.
plywood damage:
unsupported items inside the trikes' plywood enclosurs smashed through the plywood (3mm Luan) the ply also would break through any fasteners holding it to it's struts, including large headed screws and failing at glue joints
The glue joints held fine... the plys of the plywood didn't with the wood fibers separating by shearing

Not all plywood is equal:
Marine-grade plywood is a very different beast and would likely hold up to the same stresses the luan failed at, but I'm specifically referring to mr atomic's choice of 3mm luan, which I think is crap as a structural shell- but that's just my opinion and should be treated as such.
Marine-grade plywood is also significantly more expensive.

 

[flangefrog]

Well I checked the price of marine plywood and it's not too bad here, but it's only available in 4mm minimum.
I also had a look at aluminium, and for a sheet slightly thicker than used on the Alleweder velomobiles it's still less than half the weight of plywood.

If the NuVinci has plenty of range then why did you choose to also have a rear derailleur?

 

[ddk]

Well I checked the price of marine plywood and it's not too bad here, but it's only available in 4mm minimum.
I also had a look at aluminium, and for a sheet slightly thicker than used on the Alleweder velomobiles it's still less than half the weight of plywood.

If the NuVinci has plenty of range then why did you choose to also have a rear derailleur?

I only used the gear cage... not the derailleur. That was used to ease making the choice for the final sprocket.
After experiments were done, I fixed an 18-tooth sprocket to the rear axle. The 18-tooth is driven from a 44-tooth sprocket affixed to the hub flange of the NV.
Experiments were done to set up the motor/pedal ratios for the trikes' max/min speeds I was interested in attaining.

(my opinion again)
Think about minor collisions before using aluminum or any sheet metal (my opinion again)
Plastic gives where metals crease

 

[bowlofsalad]

The purpose of the motor is not really to get me going fast, but to help up hills

What makes climbing hills easier isn't aerodynamics, it's less weight. A velomobile is going to weigh more than a regular bike/trike.

If all you want is to be able to climb hills with ease, get a mid drive or geared motor and forget the velomobile. If you care about details like range and speed, go with the velomobile.

Riding an ebike up a super steep hills such as the one featured in the video you linked to will probably need your help pedaling. If hills such as that are common routes for you to take, I'd probably go for a mid drive with a robust set of gears.

 

[flangefrog]

(my opinion again)
Think about minor collisions before using aluminum or any sheet metal (my opinion again)
Plastic gives where metals crease

Yeah I'll probably wait until I've built the frame before making a final decision on any material, None of them cost too much so I could even try several different fairings.

What makes climbing hills easier isn't aerodynamics, it's less weight. A velomobile is going to weigh more than a regular bike/trike.

If all you want is to be able to climb hills with ease, get a mid drive or geared motor and forget the velomobile. If you care about details like range and speed, go with the velomobile.

Riding an ebike up a super steep hills such as the one featured in the video you linked to will probably need your help pedaling. If hills such as that are common routes for you to take, I'd probably go for a mid drive with a robust set of gears.

The motor is for hills and also for extra range, the velomobile is to keep me warm and dry in any weather (and because they look cool), extra range or speed is a bonus. I really want this to replace a car for me. There aren't many hills that steep around here but if I go on a trip I mentioned earlier then I would have to be climbing a mountain range for a couple of days on a gravel road. Most the road is not that steep though.

I think I can pedal about 100km a day on the flat. but I don't think I'd output more than 100W average (probably more like 50W).

Since I want to try the NuVinci hub, the goldenmotor 800W looked good as I can have a one stage reduction (not including the NuVinci) and I assume it will be more efficient than a DD hub motor as a mid drive due to it's higher RPM. I've looked at the unite motors (including the GNG kit) but they all have an extra stage of gearing, or two in the case of the GNG mid drive. It's also very nicely priced compared to the other options. When travelling on the flat I would like to run at only around 300W most the time (keeps it legal apart from when it's climbing)

 

[johnnyz383]

Very interesting debate...a couple of things...in so far as building a velomobile, i think it just makes sense to have an electric assist and further electric powered. The sheer bulk and weight makes me think that making a hybrid velomobile alot of sense. When it comes to power and what kind of drive however, i would say for me, i would want a system capable of producing a max of about 2000 watts, and have this combined with either assist or being able to propel the vehicle without assist. I would design it with the battery, controller and motor in mind, using a mid drive going through the gears. I have proven that this is a great setup and works.

john

Arctrike.com

 

[John in CR]

Before getting too far along on the shell plans, you might want to look at the method use here for building outrageously light boats http://gaboats.com/boats/sweetpea.html . By using the trike's structure as part of the frame for the shell, I'm sure this could yield a far lighter vehicle that either colorplast or plywood, as well as more structurally rigid since the weight is invested in the skeleton support joined by Kevlar roving. From what I've read it's surprisingly tough, and if you do get a cut in the skin, simply duct tape it from the inside for a temporary almost invisible fix. For a permanent fix, just stretch new piece of Dacron over it and shrink it tight and smooth with a heat gun.

Just an idea. It's how I will go when I build a velo.

John