Full-Suspension Semi Recumbent Cargo Bike - NuVinci MidDrive

[Harold in CR]

In your drawing, how do you figure the leaf springs will flex ?? One end has to slide as the leaf flexes. You have the leaf as moving in length instead of up-down ??

Its tough to go by a drawing, though ??

[amberwolf]

Well, based on the way the trailer kits I've seen these on appear to work, the L-shaped end is fixed via bracket to the frame so it doesnt' move, and the axle is attached via a pivot mountint point to the white pivot point on the other end of the leaf, with the "swingarm" pivot of the axle mounted somewhere between them on the frame. So it appears that it compresses/bends the leaves in order to absorb shock motion.

I am probably misunderstanding how they are originally mounted, and if so, then my pictured setup will not work, and I'll have to figure out how they *actually* are mounted, and do it that way if it's possible.

My pictured version would be just like it looks, with the L-shaped end under the seat, clamped via U-bolt/plate to the bottom of the square tubing there, butted against the seat tube so it can't move forward under compression. Then the white pivot point on the other end of the swingarm is mounted to the shock mounting point on the swingarm. The swingarm's pivot point is mounted to the dropouts of the main frame.

That would put the load from the wheel up in an arc into the leaf, compressing it against the frame, theoretically pushing the arc of the leaf down to bend under load/shock.

If that wont' work, I'm not sure how to utilize it.

[Harold in CR]

One end of a leaf spring has to move. The spring action is in the center of the spring.

With what you have, there is not a lot of travel in the swingarm. You would need to mount the leaves so that the swingarm pushed down on the ends.

As I said earlier, this is a drawing, and, the actual design MIGHT work, but, I can't see it doing anything the way it is drawn.

In one of MichaelPogues renderings, he uses Carbon Fibre leaves. You might look into his thread and see what I mean. IF you can do something similar, you would have a good suspension.

Maybe I am just not seeing what you are ??? ???

[amberwolf]

Apparently I need to learn more about leaf springs and how they work; I thought they worked by bowing in the middle, based on what I thought I remembered from trucks in shop class more than two decades ago, but that's not what happens based on your description (which is probably right, since I have never actually used leaf springs before).

I'll do some reading up and figure out how I *should* use them, and see if it'll fit.

[amberwolf]

I did some more fitting and pondering today, while moving and reorganizing stuff in the house so I can actually find things again.

I discovered that the original "good idea" isn't, really, as it would force the seat to be too high and too far forward:

DSC04073.JPG (44.61 KiB) Viewed 4522 times

Note taht in the mockup, the motor ends up a couple of inches away from the middle downtube, but in reality it'd be a couple millimeters away, with the headtube/seatpost angle being matched instead of messed up.

So, since there's no way to join the headtube and seattube (for strength) without moving the blue frame down and forward, which then fills the space the motor would be in, it means the motor can't be in the dropouts, and I have to make dropouts for it. Either below the green triangle like this:

DSC04072.JPG (44.88 KiB) Viewed 4522 times

or below the blue triangle.

Note that in the latter mockup, the headtube would align directly with the seatpost, so I'd basically cut off the blue frame's headtube and fishmouth the top/downtubes of the blue frame so that I could weld them directly to the back of the seatpost there. Actually just a bit higher, after cutting out the crossbar on teh top of the green triangle.

If I could manage it, I'd ideally like to align the toptube of the blue and green frames, to pass their line straight back and down under the seat, and have the seat mount directly to the top of them. That depends on ground clearances for the stuff along the bottom (pedals, motor, chain) at full bump of the suspension, at it's lowest point of travel (most compressed). Might not be able to, and end up with what you see in the mockup.

If I do manage it, the seat will be tilted back more (which I want), with it's base/back joint still in about the same place it is now. I may have to bend the front edge of the seat downward to clear my legs for pedalling, though.

The square silver rails would be to mount the cargo pods on, and also to provide support for the seat. I'd probably also have to add lower rails like CB2 has, to keep them from hitting the swingarm when loaded, but the lower rails won't have any rear-end support, and will have to extend beyond the rear wheel so I can put a cross-brace on all four rails to keep them spread apart back there under loads.

I also wish the rails could go higher, above the top of the tire, but they can't and still stay inline with the rest of the frame top (which I want), so the pods will not bolt straight across them, but at an angle across the top so the pod tops will clear the tire top thoroughly at full bump, so I can still have cargo up top.


Some pics of the rest of the room, which I've just barely started moving the bike stuff into:

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DSC04076.JPG (55.71 KiB) Viewed 4511 times

[amberwolf]

I found this page:
http://www.afcoracing.com/tech_pages/leaf.shtml
that gives me some better idea of my misconceptions, primarily thru the diagrams like these:

leaf_6.gif (14.99 KiB) Viewed 4509 times

A few other quickly-googled sources essentially show that what I thought I wanted to do is just about exactly opposite of how leaf springs are supposed to be used.

I wanted to put the load on the ends and let the middle be compressed archways.

What really should happen is the load should be on one end and the center of the arch, pushing up in that center against the one end and forcing the arch to straighten out towards the other end (whcih should be free to slide, as Harold in CR said).

I still want to try it out like I diagrammed it, just to see how badly it doesn't work. Gotta wait till I get the spring, and then see if it will even fit in the space available.

EDIT: oh, and I also have this project idea thread:
http://www.endless-sphere.com/forums/vi ... 84&start=0
which Spinningmagnets posted that Michael Plogue idea pic to, as well, and people pointed out that the way I was doing it then was wrong, too. I just forgot. Oh, well.

[Harold in CR]

Your only misconception is, You are trying to use a Swing FRAME, not a swingARM. If you can envision cutting off the upper tubes of your swingFRAME, then you have lots of possibilities to use those leaves.

Your FRAME wants to move in a radius. This is why coils are used, for the push-pull effect, on the upper part of the swing frame. You need an up-down movement. You would have to beef up the lower tube section, and add uprights to attach the eyes in the leaves, to the swingARM you have now created. The further back, toward the wheel, the better y;our leaves will work. Removing the upper part of that swing frame, will allow room for more "Stuff", like Batteries.

You have a welder. Just make a swingARM and attach that to your BIKE FRAME. I don't see any problem making that work.

Sorry to rain on your parade. I'm in awe of your designs using gathered goodies.

[amberwolf]

OK, now that makes sense, I think. I'll have to draw up some ideas to see if I understand it right, but it sounds like the way I drew up a bike once before:

I might still be using them wrong in this application, but maybe it's closer to what you mean?

CurvyBikeSketchFull2.JPG (32.43 KiB) Viewed 4511 times

CurvyBikeSketchFull1.JPG (41.34 KiB) Viewed 4511 times

[Harold in CR]

Top sketch much better. Bottom sketch, I don't see any springs, unless they are very short. IF you shorten them, they get stiffer really quick.

[amberwolf]

Sorry, bottom sketch is just an angle view of the swingarm/etc, to show how it attaches to the BB/frame. Springs were left out so the rest would be visible; it all is the same as the top sketch.

I could do this swingarm one of two ways:
A) fixed bolt/pivot at each end of spring, doesnt' slide but only bows upward in center.
B) Fixed bolt at one end (front?) with slide pivot at other end (easiest at rear), not sure if that would even do anything in this design.
Which would probably work better?
If possible, I'd certainly prefer to build the swingarm/leaf one of the above ways, rather than the one below.

I came up with another method of using the leaf spring with the existing stuff previously sketched:

leaf spring idea 2a.jpg (31.8 KiB) Viewed 4495 times

Would this one work, assuming my cargo pod frame (orange) is stiff enough?

Bike frame is all black, and would be welded as one piece. Cargo frame is orange, welded to bike frame along intersections with black frame visible.

Leaf spring is green, with it's pivot at rear of cargo frame, and the slide bracket (Ubolt of some type) onto the cargo frame.

Swingarm (swing frame) is red, and it pushes against the center of the leaf spring at it's axle, upwards. For now I'd leave it as the whole swing frame to test the idea, then build one just for this purpose if it works under the cargo loads I'd like this to haul (up to at least a couple hundred pounds in addtion to the bike's and my weight).

I guess one advantage of this way is that all the cargo weigth is directly transferred to the wheel, rather than via the bike frame. But it also means that the bike weight (and mine) has to go thru the cargo frame, and leverages against the cargoframe/bikeframe joins. Most of the time there won't be much on the cargo frame.

[Harold in CR]

Yes. That latest design would be fine. You will need to find out what weight you can put on the 2 springs, to see if it will be too stiff or too soft.

What about a shock to take the pogo effect out with more cargo weight ??

[amberwolf]

I have some dampers from powerchairs that may help with the latter.

The leaf springs I might be getting are from a trailer kit that has a bed that by itself probably weighs 50-100lbs, plus cargo capability of probably 500-1000lbs, maybe more. So with two leaf springs, it'd be too much. I'd like to figure out a way to use just one (which is why I wanted to use it forward of the swingframe, instead of beside it/above it).

I did think of a way, but it would add a lot of complication.

LEAF SPRING IDEA 3A.JPG (28.51 KiB) Viewed 997 times

Basically the leaf (ORANGE) would wind up upside down over the top of the tire, a bit above whereever the limit of swing would be. Then a rod (GREEN) comes up from either side of the axle (GRAY), pushing on the outer end of a lever (PURPLE) whose pivot point is mounted on the cargo frame (BLACK). The inner end of that lever pushes downward on the center of the leaf spring, effectively transferring the vertical upward load from the axle into a downward load onto the spring.

Does that make any sense?

I'm not sure that it would work, and given the extra complications it may not even be worth trying. But if I could make the levers compact enough and keep it all inside the frame (unlike in the drawing), it would help to leave all of my cargo frame free and flat on top for stuff.

Also, like MichaelPlogue's design, it would act as a fender to keep road crud off of me and my stuff.


I guess another way to use it would be pretty much like he did, with the normally sliding end fixed in place forward of the swing frame, angled upward and backward as if it were a fender, to arch over the tire. Then put the green rods I have in the above design from the axle to the pivot point on the leaf spring. It would then just bow back and forth, instead of the usual method.

LEAF SPRING IDEA 4A.JPG (10.98 KiB) Viewed 997 times

[Harold in CR]

The image 4A looks good. Flexing the spring from one end will give more action than flexing in the middle. Fasten the flat end and use the bushed end for the movement-swivel.

Myself, I like this last idea best. Just be sure to beef it all up solidly so no flexing of the swingframe.

I would still try to cut part of that frame off and beef up whats left, or, make a new swingarm, but, that's just me.

[amberwolf]

I'll eventually build one from scratch, but right now I just want to test the idea. Using existing parts with little or no modification is best for that, because if it doesnt work then I can just use them for something else. If I heavily modify them specifically for the test, they would probalby be unsuitable for a lot of other things they would've worked fine for before.


Plus, it's less work till I know I have to do it.


The hardest part about the last idea is fitting it all under the "rack" so I can still have low-mounted cargo across the tops of the pods, but I don't know exactly how high that top will be, yet, anyway. Gotta get the whole frame working first, with suspension, THEN figure out how low I can put the pods and still turn.

Before all that, though, I gotta get the leaf spring, so I can see how big it is exactly vs the other stuff I have.


Anyhow, in the next day or so I hope to have time in the daytime before work (cuz it's too late at night when I get home) to start cutting the blue frame so it fits up to the seattube of the green frame.

I need to make a decision before then as to whether I am going to cut the seatstays off teh green Trek930 frame, so I can fit it all together easier, and use them as support struts to extend the chainstays out and back and then inward, to make a triangulated center/bottom frame that connects to the BB of the blue frame, for battery platform/etc, and stiffen the whole frame.

If I leave the rear triangle of teh Trek alone, it is going to waste space and I'll still ahve to attach triangulation frame bits from it to the blue frame, but I could in theory still reuse the Trek frame for something else if I leave it alone. Most likely I will remove the seatstays, as that is the best way to accomplish my goal. (well, building an entirely custom frame would really be the best way, but I don't have all the right materials for that in long enough pieces, so this is the next best).

[amberwolf]

Got a chance to start hacking things apart so I can figure out exactly how to put them together.

DSC04077.JPG (25.94 KiB) Viewed 983 times

I cut the headtube of the BMX frame in half vertically, removing it's front half. That allows it to mate perfectly against the seattube of the Trek frame, after I cut away and flapdisked the seat stays from the Trek. The pieces removed are below the frame on the floor.

They'll probably be used to complete the bottom of the frame in a fashion like this:

DSC04079.JPG (23.66 KiB) Viewed 983 times

The next thing that needs to be done is to cut the BMX frame's chainstays away from it's BB, and remove the section of chainstay that is not straight tubing from the BB back to the brake studs.

Then use the tubing from the Trek seatstays to extend the straight part of the BMX chainstays to meet the Trek chainstays.

DSC04080.JPG (15.97 KiB) Viewed 983 times

Something like that. Most probably I will weld a metal plate across the width of that whole bottom section just like CrazyBike2 has under it's battery area, both as a mounting shelf and as stiffener for the bottom of the bike.

If I use the 9C/GM motor as planned, I'll have to leave a space in that plate for it to stick thru, but I am considering using one of the Fusin motors instead, if I can make it work. This would fit just behind the BMX seatpost, in it's modified triangle.

This particular Fusin has no freewheel in it's planetary:

DSC04085.JPG (44.98 KiB) Viewed 984 times

so I can use it "backwards" with the cover off my 36V fusin that has a few threads for a freewheel:

DSC04084.JPG (55.75 KiB) Viewed 973 times

Using it backwards allows the freewheel to be used by the motor to pull a chain, and then freewheel when backdriven by the wheel or pedals. I'm just not sure that the few threads this side plate has are enough to let the motor drive it under load. I expect it may shear thru them.

I am pondering a way to install a threaded section of BB cup in there instead, perhaps welded to that small threaded area (which is steel), but I am not confident I'll be able to do that in a useful way. Also not sure there'll be enough axle to put a nut/etc on if I do that. There barely is now.

As a side note, the axle shoulder on these is much wider than my 36V, so the bearing is a different type and ID:

DSC04083.JPG (62.97 KiB) Viewed 984 times

So I have to oil and tap out one of these larger ID bearings from the other cover to put into the threaded-side cover. The smaller one from that cover came out pretty easily, but the larger doesnt'.

I am also looking at my smaller #25 chains and various chainrings to use from the motor instead of bike chain. Just as a comparison, this is a 144T, 80T, and I think a 60T (counted but forgot already), along with a 16T shimano freewheel, in a 26" wheel.

DSC04086.JPG (33.42 KiB) Viewed 973 times

I doubt I'll be using them on the wheel, but rather on a jackshaft, so that I can use the Sachs 3spd IGH in the wheel instead.



I am likely to use the jackshaft Thud made for me to use on CB2 here on this bike, to combine the motor and pedal drivetrains over to the wheel. I'll have to add a BB just for it, probably below the main frame itself. I never did test this out by threading freewheels onto it, as at teh time I didn't have one intact to do so; now I do and find that it's got tight spots here and there that I can't get the freewheel past. So I've been using a BB lockring and a wrench to run back and forth over the threads, using gearbox oil to lubricate them, to cut the threads down to what the freewheel will fit over.

My hands hurt too much to finish it tonight, so the other half will have to wait a few days till I can do more of that kind of twisting. Thankfully it is aluminum, not steel, so it is relatively easy compared to what it could be.

Now I have to ponder some more to figure out what to do about some of the other issues I'm coming up against, some listed above and previously, and some yet to be posted.

[amberwolf]

Since I only have a 160mm disc on the front right now, and wanted to go as big as possible, I dug out all the discs and calipers I have, and found the largest is about 180mm or so.

DSC04089.JPG (59.77 KiB) Viewed 836 times

But after removing the riveted-on thread-adapter, I find it's holes are not ISO standard. The Promax 160 on top of it is the original from the Mongoose bike, and the 160 next to them on the left is from AussieJester. Since the original 160 is a tad warped, and rubs in places, I will swap it out for the AJ 160 if I don't resolve the fit of the 180.


Another issue is moving the caliper outward that extra 10mm. I thought, hey this should be easy; I'll take the adapter from another caliper and chain it to the one I already have. Nope:

DSC04088.JPG (79.7 KiB) Viewed 834 times

It's so far different that I can't even just drill another hole to use it. Same thing with all the other caliper adapters I have. I really don't wanna make one from scratch, especially since I *also* have to file the holes inward on the disc, and I have enough work to do on the bike to even make it rideable that I don't think I have enough time as it is.

I'm only even taking time to post this because I needed another break from the frustration, so I could ponder some more. Sometimes typing (or talking) things out gives me ideas.


Another issue I'm having is that I do not have any tubing (round or square) that is long enough (but still light) to make the pieces for the cargo rails/spring supports, which are emulated by the short square tubing in the pics.

I have a 5-foot fencepost, and some really long (8 or 10 foot) 3" tubing, but they're really thick walled and my lathe bed is not long enough to let me shave them down, even if I had time and desire to do that. I also have some square and rectangular tubing on old treadmill frames, but they are VERY heavy, and not very strong, I suspect.

I've also got bedframes, made of VERY heavy angle-iron, but again they're probably not strong in the ways I need them to be, compared to their weight.

Same thing for some rackmount cabinet rails. Either these or the bedframes will likely work fine for the bottom rails, as that's what I did with CrazyBike2 and it worked fine there so far (though I think it contributes to the frame wiggle under power).

I have those short 1" square tubes, and another even shorter 1" square, and a slightly longer but not really long enough 2" square tube, all fo which are strong and light enough to do this, but none long enough.

I also have several old tall 10spd bike frames that have lengths of ~1" round tube I could join together with smaller tube inside, that might work, but I'm not sure since the loading on this part of the bike is not typical, especially with the cargo pods hanging on there. Might still work for the DR, but may cause problems later on.

I don't actually have any smaller tube, though, that will fit right, so I have to use some of the same tube and cut a slit out of it lengthwise, then squish and hammer it into the 1" tube to make it fit. Then weld, just to be sure. Well, I think maybe seatposts might work and be tight enough, but they're heavier.

But I dont' have any other practical way of doing it just now, so bike frame tube it will most likely be.

[Harold in CR]

Can't weld 2 bed rails together, to make square tubes ??

[amberwolf]

I hadn't thought of that, but yes. However, then one "tube" will weigh more than all the rest of the frame put together.

[amberwolf]

Found some round tubing that should work, and is lighter, from a "daybed" futon-couch frame. Camera battery died so no pic yet.

Idea for the bottom frame came up at the same time; am cutting and fitting stuff now to see how it works out. Will likely end up with little or none of the trek's rear triangle in place though.

[amberwolf]

I think I have the frame figured out; it's just fit together and not welded or anything, in case I or someone else posting here figures out some stupid mistake I've made.

The couch-futon frame mentioned above:

DSC04090.JPG (46.01 KiB) Viewed 1080 times

The bike frame currently looks like this:

DSC04094.JPG (29.64 KiB) Viewed 1080 times

The Trek chainstays are spread out, by straightening them at the former bends just at where the tire would've been. This was very difficult, as they're quite strong. Had to put one foot on the seattube, and the other on the chainstay right at the bend, grab the dropout with both hands, and slowly pull until it was straight. I'm sure it's not great for the metal, but if I have a problem with it I'll replace the whole stay with some other tube. I just don't want to unless I have to.

I couldn't bend them downward, though, to make them line up with the BMX stays. So...I adjusted the BMX stays so that they'd point to where the Trek seatstays I'd removed before would be able to complete their curve (from the seatpost end) right onto the Trek chainstays. It worked more perfectly than I would have hoped for.

DSC04095.JPG (27.03 KiB) Viewed 1082 times

Then the vertical diagonal is black tubing from the couch-futon frame, running from the highest point of the bend up to the juncture of toptube and seattube on the BMX frame. Another piece of that black tubing is fishmouthed and tapped between those elbows of the bottom frame, to triangulate it and help stiffen the whole thing, as well as to prevent it moving inward or outward under loads.

I still would like to make it level between the Trek BB and the BMX bottom of the dropouts, but to do that I would have to cut the Trek chainstays from the Trek BB, at least at the top of them, then reweld them at a different (lower) angle, filling the wedge-gap with other tubing. (or cut the wedge from the bottom side, and reweld the cut edges together, but they may not be long enough if I do that; they barely are now, overlapping the rearward tubes by only 1/2" or so).


The brake studs and probably the accessory hardpoints will be removed from the former seatstays after I am sure how the frame will be done. Then the studs will probably be welded to the front fork's bridge so I can have both rim and disc brakes, which will probably be run to the double-brake handle AussieJester sent me. Then I can engage both brakes simultaneously, adjusted so they both take some of the load, and I should be able to lockup the wheel no matter what kind of load I have on the bike.


An alternate for the vertical black tube to the seatpost/toptube juncture would be to run it to the toptube/seatstay juncture instead.

DSC04096.JPG (48.79 KiB) Viewed 1080 times

I'd also like to add something from the same elbow point of the bottom frame to the BB of the BMX, to stiffen to that point, but it may be unnecessary, and indeed in the way of other things.

I'd actually kind of like to remove the entire fat BMX downtube, but I think it is needed for stiffness in the resulting bike. I'm just not sure. I know when I removed the downtube of the rear frame of CrazyBike2, to make more room in the central space, it made the bike significantly less stiff, but it was not shaped or fitted together the same way as this one.


The BB itself (a one-piece-crank type)is not usable directly, but it may work to hold a threaded BB inside it, to run Thud's jackshaft in. A possible setup of this is shown below, but it wouldn't have the jackshaft so far out to the right in reality.

DSC04097.JPG (44.06 KiB) Viewed 1080 times

In this, as in CrazyBIke2's powerchair drivetrain, the pedal chainrings are on the left, as is the motor output. Both feed into the jackshaft via freewheels installed on it. The output of the jackshaft feeds back to the rear wheel's 3spd IGH. Sprockets used were just handy and are not likely to be the actual ones used in the drivetrain.

The motor shown is the 9C/GM hybrid, but the Fusin could be used there just as well.

DSC04101.JPG (53.08 KiB) Viewed 1080 times

The chainline should work out withotu any interference to the frame and such, as far as I can tell using these loose chain strips.

DSC04097zoom.JPG (42.79 KiB) Viewed 1080 times

Another shot of the drivetrain area:

DSC04098.JPG (156.59 KiB) Viewed 1082 times

Since I might need to seriously gear up the motor for the race, I needed to make sure that the 144T #25 sprocket will fit in the space if bolted to the side of the 9C/GM:

DSC04099.JPG (47.07 KiB) Viewed 1082 times

It does, just barely. If the jackshaft is placed elsewhere or the BMX downtube/seattube are removed, then it will easily fit and clear everything.

Of course, if I gear it up that much, I'll probably have to pedal a lot just to get started up without blowing stuff up from overcurrent.

That 144T is pretty big:

DSC04100.JPG (55.71 KiB) Viewed 1080 times

but it will still easily clear the ground, too, even at full droop/bump of the suspension.

Note that the cylinder currently in place of the shock is not permanent, just there to hold the frame at the right angles and such. That cylinder is an adjustable locked-out gas spring, which means that it isn't actually a shock/spring, but rather is a position adjuster, by pressing the release pin at the tip of the extended shaft. On the powerchair this is from, there is a lever like a brake lever that remotely engages this pin, so one may adjust the ride height/angle of the powerchair.

I may well use this cylinder for that function so I can fully lock-out the suspension or limit it's travel under heavy loads, etc. Depends on what I end up with for a suspension, since that still isn't decided.

[amberwolf]

The more I stare at the frame along the bottom:

the more it bothers me that it goes up in the middle. I'm pretty sure I am gonna have to notch the Trek chainstays and angle them downward, so I can fix that, before it drives me nuts.

Also, the more I look at it the less I like having that big downtube in there, but I think I need *something* there, I am just not sure. In my head I can see how the stresses should run, and I don't see any on it, but I know the minute I take it out I'll suddenly see why I wanted it there.


I also test fitted the motor and stuff in the forward center triangle (on the Trek chainstays instead of the BMX), and it'll work there, too. If I do that, then only the drive chain is going to go back thru the rear frame. Right now, the pedal chain goes pretty far back, and the motor chain just behind it. Then the drive chain cuts back thru that area, too, on the right side. But this also means that only the pedal chain (which theoretically won't be used much) runs thru the front triangle.

Whichever section of frame doesnt' hold the motor will hold the batteries, with whatever chain goes thru that frame having to be enclosed so it can't cut thru wiring or cells or whatever, and causing me to have to work around it in battery placement.

The front section is taller, but narrower, and the rear section is shorter but wider. If I take the BMX downtube out, then the front section is even taller and deeper front-to-back, making it ideal for the batteries, and the motor can stay where it is in the pic above, since it so neatly fills that area anyway.


More decisions....

[amberwolf]

Well, it doesn't go up in the middle anymore.

I grabbed the angle grinder and cutoff wheel, then remembered that the thing power tools do best is to help me make really bad mistakes really really fast, I decided to use the trusty old hacksaw and file instead:

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I cut a narrow line almost all the way thru the bottom of both Trek chainstays just behind the BB. I left about 1/8" height (about 1/2" of metal) connecting them. Then I bent them open just enough to get the file in there, and gradually opened them up more at the bottom (open end of cut) than the top, so that they would be like a wedge-shaped cut, allowing me to angle the stays downward more.

With the cut open, like shown above, the stays are still "raised", and don't line up with the rear part of the frame yet.

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With the cut closed (to be welded when I'm sure of the results)

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it all lines up:

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Now the frame is pretty darn flat along the bottom, held level here against the floor (raised at the front because of the little bolt-ons for something I forget what it was):

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There's still a little opening in the middle of the cut, but the bottom is pinched closed:

DSC04134.JPG (18.38 KiB) Viewed 1071 times

THe weld will fill that gap, anyway. To make it no gap, I'd have to actually cut off the stays and file them perfect for that wedge shape, and that'd lose me another millimeter or two in length, which I don't want. I need as much overlap between tubing sections as possible.


Remember that short black vertical triangulator I was going to add? Now it's nearly two inches too short, so I've gained a LOT (relatively) of volume just by moving the stays down like this.

DSC04135.JPG (52.9 KiB) Viewed 1071 times

The horizontal bar still fits the same:

DSC04136.JPG (52.27 KiB) Viewed 1073 times

but I'm thinking I'll use one a bit farther back instead, to secure it to the old brake-bridge bar off the former seatstays:

DSC04137.JPG (40.64 KiB) Viewed 1073 times

That gives a bit more to weld to, and more support inside the end of the cross tube, in theory.


This is one possible way I might re-triangulate the whole center section, which brings risers up from the bottom crossbar/stay juncture, up to the BMX toptube/seatstay juncture. They wouldn't stick up like this, I just didn't want to cut the tubing until I'm sure how I will use them.

DSC04138.JPG (42.73 KiB) Viewed 1071 times

Seeing this, I'm thinking more and more that I should remove the BMX downtube and seattube/BB. Just doesnt' seem needed. But I still have this feeling I'll regret it later.



Oh, and that chair back piece I referred to in the DGA thread recently, that I wanted to make the torque arms from? It's this:

DSC04139.JPG (45.01 KiB) Viewed 1071 times

Below it are two hatchback gaslifts from a car, which while aged and not fully operable anymore, still have these useful end joints. On the cylinder end is a simplified Heim joint, which should be useful on my steering tie-rod. There's two of them, one on each gaslift. It's just a brass bushing rather than a bearing, but that should be sufficient for my purposes, at least for now.

The other end is the ball joint on the top lift shown. It screws into something at one end, and the ball is crimped onto the lift's pushrod. Not sure what I will use the ball joint for yet, but it has a bit too much play to want to use it for steering.

[amberwolf]

After asking over in this thread:
viewtopic.php?f=2&t=26650
for opinions on the BMX downtube issue, I got two replies so far, that dont' discourage me from removing it, but do re-point out the issue of triangulating the center frame, whcih will basically either require making any battery packs I use small enough to fit thru the triangles (not necessarily possible) or making one side's triangulation bar bolt-on instead of welded on.

A possible solution similar to what's suggested there:

Triangulation 1.jpg (29.81 KiB) Viewed 1064 times

with the new stuff added in blue (and the BMX downtube removed).


The top blue line is two parallel tubes just below the BMX toptube, attached on either side of the Trek seatpost and the stub on the BMX. Not sure if this will actually accomplish anything.

The two triangulation blue lines are probably what I'll do, though, even if not the top line.

Any other opinions afore I start choppin'?

[amberwolf]

Well, I finally got the chance to cut out the big tube, though nothing else yet.
Side view


Ortho-ish view:


Probably gonna do the red triangulations:


I am so tired (from lack of sleep due to the roofers banging away overhead) I fell asleep several times earlier tonite after getting home from work, to be woken by the dogs for dinner and such. I'm gonna go back to sleep soon, once I've sat here long enough to doze again. Afraid to be working with power tools and sharp things in this state, so no more till tomorrow.

A couple of things for scale:
Vpower pack plus 9C/GM:

The motor will probably actually go with it's axle *under* the frame. Likely the jackshaft for merging the pedals and motor will be under the frame, too, probably just in front of the motor. Possibly it will go above the motor inside the frame.

Just the 9C/GM:


If I had any, I could fit a metric buttload of LiPo in there.

Not sure if I'll cut out the wedge or not, as it also reinforces the headtube connection, which will be welded to the seatpost in front of it. I might trim the wedge some, so that it is a wedge in the opposite direction, though, and is less in the way of anything I might put in the open space of that frame.

[amberwolf]

Everything is going slowly, but it is going. Found the right bits of tubing for triangulation, so that I get as much volume as possible inside the frame.

Used some red bits off a kid's walbike chainstays, the rest of which had been used on the old lowracer ReCycle recumbent I never did finish, 2-3 years ago. This lets them be angled a bit at the bottom, so that there is more width in that area by a bit, for batteries and whatnot.

DSC04155.JPG (19.52 KiB) Viewed 1040 times

The forward triangulations will be the gold seatstays off an old PanWorld tenspeed. One of them will have to be bolt-on to get batteries in and out, so it'll likely get hinged at the top end (where I have more space to weld a hinge on) and clamped at the bottom end (though I have not yet conceived how, there are ponderings in the back of my brain).

DSC04156.JPG (22.23 KiB) Viewed 1038 times

Both of the triangulations meet at the bottom where the rack-studs are brazed onto the former Trek seatstays, and I will leave the studs in place so I can screw down a cover to that point later on, or even maybe to do the securing for the bolt-on end of the gold stay. If I don't need them, well, they don't weigh much.

DSC04157.JPG (21.61 KiB) Viewed 1038 times

Everything except the gold stays is now cut and fishmouthed up, just have to flapdisk off the paint around weld areas and tack it all together, then continue with the cargo frame/suspension support frame and seat supports, before I fully weld it all together. Just in case.