Thunderbolt tadpole in wood

At risk of posting my project on too many forums, here I go again hehe

I'm currently working on a Thunderbolt based tadpole trike in wood because I have neither the skill nor equipment to do any welding whatsoever but have ample tools, knowledge, and materials to build it from wood. I've purchased the full MKIII plans from http://www.hellbentcycles.com/ as they are both very complete and within my skill level to fabricate. They also seem to be a fairly simple / efficient design which are very much what I'm looking for.

The final product will be a fully enclosed velomobile inspired by the older Morgan race cars but with a much more modern and aerodynamic aesthetic. The body will be waterproof cloth over a bent wood frame.

Design requirements:

• As inexpensive as possible
• As simple as possible (and no welding!)
• Built from as many salvaged / recycled / repurposed materials as possible.
• Must have room for myself plus at least some cargo, possibly a child or two in the final product (not necessary in this first prototype)

In line with keeping it inexpensive and recycled I found a free motor on craigslist from a broken treadmill (the belt for walking on was shredded but all electrical and mechanical components were in perfect shape). According to the label it is a 120VDC Permanent Magnet motor, 2.25HP 6200RPM and 18 amps. I'll likely be running at 36v (648w) until such a time as I can afford more and lighter weight batteries. The maximum I can put through it and stay within legal limits for Oregon is 72v (6 x 12v) for 997.92w (1Kw is the legal limit) or ~1.338hp after calculating motor efficiency.

My original idea had been a delta rickshaw but after deciding on a tadpole for a number of reasons I discovered it would no longer be feasible to put the children in pannier-like seats on either side of the drive wheel.



In more recent concept sketches the pannier seats have been omitted, resulting in a more traditional velomobile design:



These were both based on the Thunderbolt MKI designs on ihpva.org and I'm currently working on new concept sketches based on the MKIII.

My main question at the moment is over how to approach the drivetrain. I'm not using a hub motor so as far as I can tell that leaves me with three options:

• A left-side freewheel on the rear hub (simplest to design but most difficult to implement given my current machining capabilities)
• A jackshaft to combine the motor / pedals to a drive chain to the rear wheel (moderate difficulty since I have no idea how a jackshaft works, and takes up the most space so working it into the design will be more difficult)
• A freewheel crank for a serial drivetrain (easy to work into the design and moderately difficult to implement without buying parts or some serious fabrication)

Are there other options than these three? Which would you recommend? I'd love to hear any feedback!

Edit: I've posted this project on a few other forums to get more exposure / answers to questions. Here are links to the others:

• My original research thread: http://www.diyelectriccar.com/forums/showthread.php/evelotaxii-44876.html
• Build log on DIYEC: http://www.diyelectriccar.com/forums/showthread.php/project-tempest-wooden-tadpole-46000.html
• Build log on the Hellbent site: http://hellbentcycleworks.yuku.com/topic/919
• Build log on bentrideronline.com: http://www.bentrideronline.com/messageboard/showthread.php?t=61097

Please keep us up to date on this. I have always wanted a nice little sports morgan it looks like a great project.

Looks very interesting!

Do you have an idea of the weight of the wood shell?

I would think you could just have a free wheel on the hub of the rear wheel or on the out-put of the motor, but maybe I am over-simplifying, I have no experience other than messing around with a little 250W brushed motor from a razor pocket bike and a freewheel from a exercise bike mounted with a rubber pipe plug (1 1/4" I think, I have a post somewhere) that I was trying to rig before I gave up and got a hub motor.

Maybe you could do something similar on the out-put shaft of your treadmill motor. The rubber plug has fender washers on each size and holds things together by compression so it has some give, and in an extreme case, it will let things slip rather than burn up, kinda like a friction clutch in it's crudest form.

@evblazer: Sure will, I'm going to need as much feedback as I can get with this project!

@LI-ghtcycle: Wow, I'd never considered a rubber plug, but I think you may be on to something! At the speeds I'll be travelling the plug would work very nicely as a failsafe "clutch" and also as an adapter for the gears. As for the freewheel I've no idea :?

Edit, Oh hey, you're in Oregon City? I'm in southeast Portland! I'll have to ride this thing to you once I get it mobile lol

i realy like your drawings!
I am in the final phase of my velomobile build, and It would have be really dificult without any weld, especialy at the wheels supports and pivots!

Good luck with your prodject, I hope to see some results soon

Oh hey this solution is quite simple: http://www.electricycle.com/ The only thing it'd need is a freewheel at the motor or jackshaft hmmm... A simpler solution would be to attach a cog to the motor, have a standard freehub without a wheel attached mounted to a jackshaft, then have another cog mounted on the left side of that just like this one except to the hub itself rather than to the spokes. In fact this is the simplest idea I've seen yet!

@bzhwindtalker: Thanks for the compliments! The Morgan sportscars are still built of wood to this very day. Instead of their aluminum skins though I'll be using cloth, which'll be much lighter weight and much easier to work with.

http://www.flickr.com/photos/exfordy/sets/72157617232647998

Kris

..The left side freewheel is not a problem. evDeals sells a hub for ~$35 with lefthanded threads on the left and threads for a regular freewheel (for pedaling) on the right. There are a number of "lefty" freewheels available. For about $75 additional you have the unique parts for your drive. You do have to assemble your own wheel: rim, spokes, hub. I've done it. Mine has a 7 speed freewheel on the right. For a "factory made" bike, you have to be sure the whole thing fits between the 135mm space between the the dropouts. Not a biggee.

.. Good luck! Looks like a fun project.

Don

KrisWood said:

Edit, Oh hey, you're in Oregon City? I'm in southeast Portland! I'll have to ride this thing to you once I get it mobile lol

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Yeah! That would be great! I'm working on a new battery pack and soon would have something to ride again with ya.

I could ride my bike now as-is, but I think my DC to DC converter is drawing too much juice for my current 9AH battery, so my new battery is going to be about double that since I also have added a 900 Lumen Magic Shine headlight for night riding.

As a fellow tadpole lover I welcome your initiative to do it in wood. There are many sites showing wood construction of bicycles, even with bamboo, so it should be workable. Also check out member Matt Schumaker's incredible drive systems for ideas.
otherDoc

Thanks for the replies

I could ride my bike now as-is

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My own bike "as-is" happens to be a 21 speed Magna mountain bike that doesn't like to shift. I've ridden it all the way to downtown oregon city along the 205 bike path but oy it's a long ride. I can't wait to do it with hill assists!

Matt Schumaker's incredible drive systems

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I'm not sure what this means, but I'll try looking it up!

Edit: Is this it? http://www.recumbents.com/WISIL/shumaker/default.htm

Edit: I've completed drawing my new plans based on the Thunderbolt MKIII. The main things that changed were the stays and how far back the seat is, which simplified the design and made it quite a bit roomier at the same time. I'll post a scan of them later today. In the new design I've opted for adding a hub on a jackshaft just behind the motor, with a single small gear on the left side which drives a single large gear on the left side of the rear wheel. This way there is no modification of freewheels necessary, there'll just be one extraneous chain which should have a minimal impact on efficiency. I'll want something better eventually but for the prototype and even the production version at first, this will be enough. Lastly my new design is simple enough that I may not need to make two prototypes, or even a separate production version; Just build the one prototype and modify it rather than starting anew.

KrisWood said:

Thanks for the replies

I could ride my bike now as-is

Click to expand...

My own bike "as-is" happens to be a 21 speed Magna mountain bike that doesn't like to shift. I've ridden it all the way to downtown oregon city along the 205 bike path but oy it's a long ride. I can't wait to do it with hill assists!

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If you live want another good ride, take the springwater corridor path to where it connects along the river and heads south to Ore. City, you get great scenery going along the waterfront & past Oak's park and then you connect to river road once your in Milwaukie. No way to avoid that monster hill, just gotta choose where you want to go up it. :wink:

Looks like Dr. Bass should have batteries to send me in about a week, and hopefully GGoodrum & Friends will be selling there V4 BMS so I can build my new pack! 8)

Hi Kris,

I'm looking forward to seeing how your build turns out. I'd be more inclined to use aluminum and pay someone to weld it up. I think wood can work well too and it will be very interesting to see how you solve the various issues.

Matt Schumaker's incredible drive systems

Click to expand...

KrisWood said:

I'm not sure what this means, but I'll try looking it up!

Edit: Is this it? http://www.recumbents.com/WISIL/shumaker/default.htm

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Yes but I think Doc meant to check some of his build threads and RC drive related threads on ES, user recumpence,mostly in the non-hub forum.

Glad to see you made it over here; I did figure you'd get a lot more useful responses on ES than DIYEC for this type of project.

Perhaps you could post a link to your DIYEC build and research threads, in case any of that info is helpful to others to know what has and hasn't been covered.

The ease of welding in factories and the improvements since 1900 in metals has made wood fabrication more and more a lost art.

But it is still a good way to do things sometimes, to make it from wood. It really can be a good way to homebuild. Look what the Wright's made from a few sticks and fabric connected with a few metal brackets and wire.

Go for it!

Had these picture's on file not sure if they help but here they are.
I have some picture's of another woodern trike some where i will see if i can find them.

Thanks guys! It should indeed be a fun project.

Yes I'd seen that wooden trike before. The guy who made it has a blog devoted to the building of it: http://www.borisbeaulant.com/

I'll post a link to the DIYEC threads in the first post of this thread so all my starting info is together here.

Reposting the link here too for the sake of repetition.

• My original research thread: http://www.diyelectriccar.com/forums/showthread.php/evelotaxii-44876.html
• Build log on DIYEC: http://www.diyelectriccar.com/forums/showthread.php/project-tempest-wooden-tadpole-46000.html
• Build log on the Hellbent site: http://hellbentcycleworks.yuku.com/topic/919
• Build log on bentrideronline.com: http://www.bentrideronline.com/messageboard/showthread.php?t=61097

BB, if you decide to build a metal trike instead, i have some old bike frames, bill has a welder and knows more about building bikes than me too, plus he is on BROL also. he just built a leaning trike for the epower challenge. he is out on the other side of 205 off foster and i am downtown off clinton.

you should verify your motor will run on 36V if that's what you wanna do. i was surprised when you said the motor is labeled DC and used in AC app. but i just was salvaging an electric mower and found a big 4 terminal bridge rectifier mounted inline so it converts the 125V AC to nasty DC for the motor.

Wow, thanks for the reply! I had no idea there were so many enthusiasts here in the Portland area! We should all get together some time and hang out / compare notes! I'm on Se 115th a few blocks from Foster myself

Yes, the motor will run on 36v DC. Amberwolf has the exact same motor (well, almost, his is a little more powerful than mine but it's the same brand, also out of a treadmill, and almost identical specifications) and he was able to run it in that configuration. His success with it is part of the reason I chose it in the first place. The AC to DC conversion occurs in the controller / power supply which are on the same circuit board.

I'm not entirely opposed to metal but the idea of building it out of wood still seems very exciting and fun to me. If wood does not work out I'll certainly take you up on that.

I started cutting out pieces for the 2x4 prototype version today! Pardon the small picture, the only photographic equipment I have at the moment is my web cam. Next I need to get a wood rasp, some bolts, and a drill bit the same diameter as the bolts so I can assemble these. I also need to figure out how I'm going to do the crossmember arms.

Looks good! I'm really curious, is there any weight penalty using wood? I mean, I would imagine it compares in strength to aluminum?

I haven't weighed it but it's pretty darn light so far. Can't be more than 5 or 10 lbs but it's going to gain a lot of weight once I have the crossmembers, stays, and hardware.

Here's a web site that might help , the guy design electric wooden vehicles in the uk.

It might help unless you have this site already.lol or it might help other people too.

http://buggies.builtforfun.co.uk

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Great link, thanks!

Thanks also for the drawing of the steering setup, it confirms a lot of my ideas for a bolted together knuckle system, and gives me more ideas for how I might do my crossmembers.

One advantage of using wood is that when it rains too much you can float it across the flooded roads.

Found these picture's in my files too:
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