Here we go again

SimpleSimon

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As most of you probably know, my trike got backed over and smashed by a hit and run driver Tuesday while I was in the Comcast office paying my bill. I've been pretty bummed out - the frame was twisted, the engine crunched, and the rear axle frame bent - it is pretty much a write-off.

So, with the encouragement of several folks here I decided to see what I can do to get back on the road again. I have a whole bunch of 1.5 x 1.5 x 1/8 inch angle iron "(steel bed frames, actually), and I have a sawzall with hacksaw blades. I can get a 4 foot long 1.5 x 1.5 inch square tubing joint for $5 from the local scrap yard, which is sufficient to make a drop center front axle assembly, and the front boom the sliding boom for the BB will fit into.

So, I spent today doing a sketchup model to clarify my ideas. Attached is a view of that as a basic frame and wheels only. I'd appreciate any and all comments, suggestions, etcetera. As drawn it is intended to be a rear suspension twin rail ladder frame, although I need to check some references on shocks to ne sure I size that mount correctly; as a consequence the shock tower is not yet drawn in.
 

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  • Angle Iron Tadpole.jpg
    Angle Iron Tadpole.jpg
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SS..if anyone can design a good tadpole ,I would bet on you..Steel would be better than aluminum..have a lifetime of experience with both materials..welded aluminum joints are an entirely different design than steel when any stress whatsoever is involved..I myself would use steel also..Thanks for your pms regarding the design of my tadole but I am putting that build on hold for a while till I am fully recovered from my MB crash last Dec..will stay tuned in for progress reports on your tadpole..I like the looks of that frame and the larger rear wheel..is that 26 rear and 20s in front? Are you going for rear or full suspension?
 
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That's looking pretty good, Patrick. Looks like you'll be able to get a fair bit of rear suspension travel. Great drawing, too. What software are you using?
 
I like what you have so far. Looks good.

Let's skip ahead to the engine power..... what are you thinking? Rack mount or do you want to fix your current HT engine. (I have some 50cc HT engine parts.... square jug, with good fins)

I've also got an extra pair of matched, bicycle headtubes & steertubes; if you want them to build your kingpins.
 
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Addressing the questions in order, yes, Tedd, I intend to go with a 26" rear wheel (since I have a good stout one already laced with 12 gauge spokes) and 20" front wheels. I prefer steel myself, since that is a material I am both more familiar with and am already in possession of.

Aussie, the software is Google SketchUp, which is a truly excellent 3D modeling tool with a great range of flexibility and excellent support. Best of all, it is free from Google. I use it a lot.

Srdavo, I think I am going to go with an R/S engine GEBE kit, which vegaspaddy has been kind enough to make me a truly excellent deal on. I should have that in about a week. I know the GEBE kits are usually a vertical rack mount, and this design will accomodate that very well - however, if the engine dimensions will allow, I'll cantilever it forward off the rear triangle frame. I am uncertain if that is feasible, but if it is it will lower the visibility of the engine assist quite a lot.

It is that remaining uncertainty that leaves me unready to complete my design at this point, along with needing to check shock reference guides for dimensions. I know the majority of tadpoles use a variant of a sling seat, but as it happens I have a stout, very comfortable, adjustable backed steel office chair I am contemplating sacrificing to the cause. It has a lockable swivel feature, and an internal gas shock central support stem with about an inch and a half of vertical travel. I figure that chair, with a rear suspension, will make for a very smooth ride.

Have you got a pic of the headtubes? If they'll work in my design (which is readily adaptable to changes) that would be very useful indeed. As the sketch shows, I intend to go with a center column steering system to a bell crank and tie rods to the steering arms.

Thanks for the comments/questions, guys. It is this sort of interaction that makes this community my favorite place on the 'net.
 
simon, this is all really good news...in order to help you in your planning, i'd like to pass on that the eho35 requires a near level mounting position, it can't be "rotated" like the tanakas. however, after you see the components, you may agree that it (maybe) could be made to fit nicely in front of the rear wheel if you're willing to provide the mimimal stretch necessary...pedal-chain routing might be a can o worms tho.

i'll be looking forward to updates :cool:
 
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simon, this is all really good news...in order to help you in your planning, i'd like to pass on that the eho35 requires a near level mounting position, it can't be "rotated" like the tanakas. however, after you see the components, you may agree that it (maybe) could be made to fit nicely in front of the rear wheel if you're willing to provide the mimimal stretch necessary...pedal-chain routing might be a can o worms tho.

i'll be looking forward to updates :cool:
I was aware the contemplated engine would need a level mounting position - what I am contemplating is cantilevering a "shelf" forward from the near vertical rear triangle stays (which will be 1/2" square tubing) to mount the engine to, with the belt run (pulley center to pulley center) nearly horizontally. Engine dimensions will determine if that is feasible, as I'll need to allow clearance in the vertical plane for the action of the rear suspension. I am contemplating a single rear shock forward from the "ears" on the top crossmember tie of the rear assembly. I may fabricate a pivoting swing arm to translate the plane of motion through a sharp angle, or perhaps go with a pair of lighter shocks at the upper corners of the rear triangle.

I'd like to keep the profile of the final design as low as I can, partly as a matter of aesthetics and partly as a matter of reducing drag. For similar reasons I may drag the frame components to a shop with a good drill press and lighten the angle iron by turning it into "drillium" style material. By my calculations I can drill out 3/4 inch diameter holes on 2 inch centers, staggered by a 50% offset for the two flats of the angle iron, and reduce frame weight by about 25-30% while actually making it stronger (the internal shifting of stress lines in the steel that drilling it creates stiffens flat plate if not excessive).

The rear pivot is intended to be a hardened 1/2" steel head bolt, on which I intend to mount a pair of sprockets on a common bearing sleeve on the right side. That will put my chain run internal to the ladder frame rails, and will give me a short final drive loop that pivots freely on the rear triangle pivot axis - which means that chain idlers and guides are minimal, That, of course, is part of the consideration in whether or not I can forward cantilever the engine mount as well - there has to be unimpeded clearance for the top chain run.

Those sorts of considerations are a large part of why I like SketchUp so much - checking swing arm clearances is simplicity itself with a simple flat diagram in that program.
 
Hi SimpleSimon,

Why not use an electric hub motor for the rear ?

Trikes like yours could have plenty of ways to mount batteries low.

That would also allow using SLA batteries and they are somewhat cheap.

I have all you would need except batteries, cheap.

Thanks, Steve
 
GEBE position:
http://motoredbikes.com/showthread.php?t=4956

looks like about anywhere is possible.


My camera batteries are dead.... here's a link to my kingpins:
http://www.motoredbikes.com/attachment.php?attachmentid=15182&d=1234575228
I do recall seeing the pics of that stretched cruiser - beasutiful job he did there. Augi's engine is mounted at a forward rake of about 20 degrees on Sabrina, as well.

The kingpins are modeled on the design you've posted links to previously, I take it? If so, then yes indeed, they will serve me very well, as that is exactly the model I intended to follow in fabricating some. The nice part is, they'll fit very well into the drop center axle I intend to build. The steering arms will function well to hook the tie rods from the bell crank to as well.

Question: where did you get those truly excellent looking front wheels? They are exactly the type I have in mind, especially if I can affix a disc brake rotor mount to them.

I want to mount the caliper casing to the tops of the kingpins, so they swing with the wheels - if I can figure out how I'll also mount a 50 watt rectangular fog light fixture to each so that the headlights pivot with the steering. Tail lights will be a combination orange blinker, and a red brake light, with turn signal lamps on outboard stalks. I intend to put a rack for pannier type bags on the rear triangle , but keeping it just clearing the rear wheel, as the rack will of course move with the rear suspension.

A compressed air canister type boat horn (which I already have), and front fenders I intend to fabricate by lost foam molding of fiberglass, with integral top mounted turn signal/running light nacelles, and it will be truly what I want it to be.

Many thanks for the kind offer - I'll gladly accept.

PM incoming.
 
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