1982 MB-5 build (painted frame 4/14)

[hillzofvalp]

I just noticed that the flats of my swingarm are not parallel. They are angled away from each other.. Wider on bottom then on top. Are yours lik ethis too? I would have to make a .5-1.5 degree angle compensation on the extensions to ensure that I'm not snapping axles

[Drunkskunk]

My swing arm is perfectly parrallel. yours may have gotten tweaked at some point.
No bigl advantage of a monoshock at 50mph. it just lets you use the ready made longer swing arm. but it looks like it would go too far forward.

The holes in the top tube, left to right. the square bracket with the single hole is the top mount for the air filter box. the rectangle bracket with 2 holes is the mount for the ignition coil. On the oppisite side, the hole is for the bottom mount of the oil tank.

The gas tank mounts to the two threaded holes in that hump between the top tube, and the two downtubes. The tank sits on rubber pads there. At the rear, it mounts to the two non threaded holes on the arch that goes over the back wheel. (not in that picture) it uses some tiny #6 bolts with rubber grommets. There is also 2 rubber blocks that the tank sists on for support under the seat. those blocks are held on buy pressfit tabs on the flat part of the rear tubes, into the two non threaded holes on either side.

[hillzofvalp]

Cool.. I'll use them to mount the bms or something.

Today I took the grinder to the dropouts to get ready for welding. Took off one of the tensioning lips.. Modified the other to hold the phase bundle.

I worked a lot today on making a jig to place the new torque plates/swingarm extenders as close to parallel to the swing arm cup faces possible... Still experimenting. I think I will extend the swing arm by about 1.5 inches. They will be about 16mm thick or around 5/8" each. Existing spacing is 182mm minus 144mm minus 6mm drive side spacer (divided by two). I'm going to try my best to get these plates as parallel as possible so I don't over stress the axle.

It might be a bad idea to work on torque plate alignment without having the swingarm fully assembled.. But I figure worst case comes to worse I can cold set the legs later.

[hillzofvalp]

THis is 12p28s configuration.

gettin' there.. I found some leftover carbon fiber sheet from an aerospace company sitting around.. so the blue panels will be carbon fiber. Sides are milled out .25" and .5" aluminum. Also scrap hopefully... I wonder how close to the nominal weight I will be with all wax, aluminum, and carbon fiber. I'm hoping within 6-7 lbs of the 51.85lb nominal weight.

I left the front module flush with the bottom like in the rear for the sake of simplicity.. fewer parts to make.. and I guess lower CG. I may choose to cover it all up anyways with custom fiberglass fairings.

Drunk skunk, is the top tube near parallel with the ground when bike is built up? If not, how much of an angle? Looks like 5 degrees or so. I may choose to mount pack at an angle from top tube to make it parallel with ground for cosmetics ( and lower CG?).

[Drunkskunk]

Its not horizontal at all, its at an angle down. the head tube sits at a 25 degree rake, so if you tilt your frame back to that, you'll see it.

Random internet pic of how it sits:

[hillzofvalp]

How much do you think the motor stiffens the frame?

[Drunkskunk]

A lot, actualy. But that can be solved with something like the under bars seen in that pic you posted on page , of the white and red bike. just something that ties the head tube or top tube to the foot peg area

[hillzofvalp]

I've left room in the design to accomodate 1/2" aluuminum (near voids in the picture above)... which will attach to the top tube motor mount, then I'll make some big aluminum arms that go on top of the carbon fiber and traverse to the opposite corner near the pedal mounts.

Think I should just modify the frame and add the bar you're talking about? Or will the battery pack be enough?

[hillzofvalp]

The bushings in my swingarm seem pretty dried out.. cracking a little. Should I leave them as is? Probably hard to find replacement

[Drunkskunk]

It should be a bearing, not a bushing. I'd replace it if it doesn't clean up well. Honda dealer should have it, may be interchangeable with a CR60-80 swing arm bearing.

Also, I measured the top tube at 12.5 degrees on my bike, although I have dropped my front end 2cm

[hillzofvalp]

If its a bearing, then it's a nasty one. They are pretty frocked up. When I fixture the dropouts for welding, should I reference the flats to the outside of one of the bearing cup faces? Or is it necessary to replace the bearings and insert an axle as a reference?

Here is the new mock up. Got the head tube at about 24-26 degrees. There is some room for error in the model. Only the long pieces are the battery modules. One more would go vertically nex to the front one.

[hillzofvalp]

It should be a bearing, not a bushing. I'd replace it if it doesn't clean up well. Honda dealer should have it, may be interchangeable with a CR60-80 swing arm bearing.

Also, I measured the top tube at 12.5 degrees on my bike, although I have dropped my front end 2cm

I was told by another mb 5 owner that it is actually a bushing. That's what it looks like to me, too, cause it doesn't spin and there is cracked rubber. Maybe yours is different. Would a bearing be a better idea? Bushing probably offers smoother ride.

Update:
Got phase change material. Pretty cool stuff. Light. But messy. They weren't all the same size so I'll have to mill them to the same spec so the compression across the whole pack is relatively even.

[hillzofvalp]

I think I am going to stick with the front original MB-5 mag wheel and try to spec out a custom spoked front wheel to match the rear later. The cromotor I think will have a 17" rim such as this 2.75" wide version (http://www.buchananspokes.net/categories/rims_sun.asp) (pricey at $230!)



with a 90/90-17 rear tire (meant for front wheels?)


If my calculations is correct, this will make a 23.37" wheel diameter (maybe less since such a wide rim). Which will put me at 55-60mph with this setup.

[hillzofvalp]

Prototype enclosure. blues are 1/4" thick aluminum milled out to lighten. Corners are billet 6061. Little pads are for an aluminum brace that takes the load of frame (originally motor acted as frame stiffener. I didn't want to put all force through the battery stacks and the 1/8" carbon fiber. Should still come out much lighter than if 1/4" aluminum was used for panels instead.

Luke, insulating this is going to be a nightmare. 3" kapton on order. Garolite also. Formex here already.

[hillzofvalp]

Well, I'm pretty sure that in this mockup the downtube is around 12 degrees. I need to check in photoshop. The support braces shown in mockup that take load of frame flex are just placeholders for reference. Here's where I'm at:



One battery lead would exit the very bottom rearward edge and double as a drain hole. The second lead and balance leads would exit just behind the down tube engine mount. This area would be protected from rain for the most part.

Like so far? Lots of parts to make! More overwhelmed than I expected!

Note: Keep in mind that the finished width of this pack will be right around 6.22". Pretty thin. The reason I'm packaging them like this is that it requires the fewest parts. It important when working with all cell pcm to compress the pack a bit so that everything is secure and there is an adequate thermal path between the aluminum heat sinks.

Other benefits might be:
aerodynamic advantage
better weight distribution
better appearance
more direct, neater path for the support braces to take (probably 3/8" aluminum).

Cons:
No fitting high efficiency Astros in here after this pack is built.
wind? nah.

[Jeremy Harris]

Looks pretty good to me. I reckon the pack side panels should add a fair bit of stiffness, even if they are thin, as they'll be well supported. You've effectively added a well-braced monocoque where the motor used to go, which should do the job.

I found packaging everything in the frame far and away the hardest part, one reason why I put my bike project to one side for a while. Seeing this has spurred me to thinking about getting on with it again, though!

BTW, my RD50 uses rubber bushings as swing arm bearings. Maybe some of the MB5's did, too.

[hillzofvalp]

I'm going to have to re-do the pack because I thought the swingarm mounted where the kickstand mounts.... Weird. In above picture the hole just below the biggest circular punch out is where the swingarm mounts! Weird!

[Farfle]

I'm going to have to re-do the pack because I thought the swingarm mounted where the kickstand mounts.... Weird. In above picture the hole just below the biggest circular punch out is where the swingarm mounts! Weird!

Doh!

[hillzofvalp]

It's kind of a good thing really.. Now the pack will be wider, more compact, and easier to package. Only problem is I have to forfeit all my 6" aluminum

[hillzofvalp]

Finished my swing arm extensions.. I'll upload pics tomorrow. They turned out really nice. .68" thick with 5/16-18 pinch bolts. They allow about 1.4" of travel for the axle to adjust wheel base

Still fussing with the pack design. Trying to optimize for 7" width now as opposed to 6". Might have to go down to 11p from 12p, which I don't really want to do....

I wish I had closeup pictures of the swing arm where it attaches to frame. I'm going to call up my mb-5 parts supplier to see if he can send me the necessary hardware so I can have an appropriate prototype made !!!!

[Drunkskunk]

I wish I had closeup pictures of the swing arm where it attaches to frame. I'm going to call up my mb-5 parts supplier to see if he can send me the necessary hardware so I can have an appropriate prototype made !!!!

The normal kickstand is missing, the brake lever is custom, and the exhaust runs under the bike in this pic, but the swing arm is unmodified.

[hillzofvalp]

Awesome! So there is nothing that goes past the outer perimeter of the bushing cups on the swingarm I take it. Looks like thats a 12mm axle? I measure the bushing holes and got a little over 12mm.. maybe they are shot.

Here are my swing arm extensions... In current form they are 5.5" long, allowing 2-3" overlap onto the swing arm. .68" thick. 1/2 degree taper on the welding flats because original swing arm flats were not what you'd call perfectly parallel, but good enough for its previous purpose.

In this picture you can see that I overmilled part of the slot.. I did these manually on a CNC machine and someone distracted me...




I'm having them welded professionally. Still need to hit all the edges with a grinder. The slots are a hair over 10mm, but the pinch serves to just close that gap (not clamp). I don't plan on cranking those down hard.

[hillzofvalp]

This is the latest mockup of the pack.. delta q charger in green.. but would be a tad thicker I think.

I'm still waiting on cells, shrink wrap and machine time to mill the graphite paraffin wax. I also found out I need a non-standard end mill to machine it so that's another $50 deeper in my wallet..

I could start on the aluminum parts of the enclosure (7" all the way around).. and just oversize them a little and face them to size after I have the cells packaged completely with balance leads in pcm, G-10, formex, and kapton. I was told by someone what the finished diameter of the pockets should be (26.4mm), but I can't trust that until I have MY shrink on MY cells.. I would hate to frock up all the pcm...



WElding is going to be a disaster for this pack... my original design was to link all modules together as one continuous string (think 5 foot long chain of 7-8 blocks), then fold them all over. THe only issue is that once it gets long, it will be very difficult to continue welding. Might just have to hang the rest of the pack off the tab welding table on a cart that will make sliding to the next cell much easier. 1344 welds total.

[Alan B]

Too bad you can't CNC a spoked rear rim to match the front and fit the Cromotor.

[hillzofvalp]

I suppose I could but I'm not an ME... I have no idea how I'd attach it either. However, the other type mb-5 wheel would look fine with a rear cromotor laced conventionally 17" rim. I was hoping to just build my own front wheel as well so they match.

You have to remember that the diameter of the hub would probably mask most of the spoke design even if I tried to cnc one.

edit: thought: maybe I could dismantle the rear wheel, lighten the components a bit, and then affix them to the conventionally laced cromotor wheel on top of the spokes! that would be super jank but might look cool...