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

[hillzofvalp]

One more module (7 total) will go in front of the rear tire. drywall stacked this way came out to 66mm, which is a good approximation for 26650 modules with nickel and garolite sandwiched in between. It's easier to work with than you would think, and a good, rigid alternative to cardboard. it cost me $5. I think I already said that.

The frame is painted and taped weird because I was trying to stich it well to make a 3d model with 123D catch from autodesk. Turns out that software doesn't really like structures like this, unless you get the lighting perfect.

[Drunkskunk]

I'm really curious how this will turn out! I'm an MB5 fan. I had mine up to 60mph this weekend with the new pipe. If you can beat that, I may convert mine to Electric

If I can make a sugestion on the rear swing arm, the rear wheel sits far forward. it makes for some strange handling quirks at high speeds and makes the nose feel light unless you ride in a tuck at full speed. Not a big deal, but I can feel the diffrence between the axle al the way forward and aall the way back in the adjuster.
I'm planning to extend my swing arm 2 inches, and you may find that adding some material to yours makes it easiet to also modify it for the spacing you need.

I'm watching with intrest to see wht you find for a front wheel. I suspect a CR80 17" from the mid 90s should fit backwards, with the disk, but I haven't found one to measure yet.

[hillzofvalp]

Awesome! Keep the tips coming! I'd be thrilled to hear more about your experience with it.

Do you think it would be worth just making a new swing arm out of a block of aluminum (free block)? Probably takes too long. Have you welded it before? What kind of Steel is easiest to weld on it? I have to add two .675" thick torque plates to the inside. In order to get to cromotor spacing. I want to use doctorbass plates but they're only .375" thick. This is where a custom swing arm might make sense.. And maybe even make it a unishock


With a 23" wheel it might do 50-52mph. With field weakening on, I may get it up to 55. I am limited right now by the controller (18FET 4110 to start).. So now is the time to convince me to buildit into a higher voltage pack. Also, balancing with hyperions is easiest at 28s...

But I have some linear bms boards that will allow up to 36S.

Edit: I can always go up to a higher kv hub I guess...

[Drunkskunk]

Milling down a block of Aluminum would be awesome, but expensive and hard, and heavy in the end.


However, the CR80 from the late 80s (big wheel) is a little longer swing arm, and monoshock. you would just need to weld a mount to the center spine on the frame. Lots of pics on google of it done to MB5s.




Actualy, thats the bike from the bike pron pic you posted, the unoccupied one

[hillzofvalp]

Love that bike. Actually, right now with the batteries the way they fit, I'm not sure a mono shock would work.. I would have To make a smaller pack. Do you know how far the mono shock goes? See my above pic. While looking at it, also please tell me what the different threaded holes are For on the top tube. I was given a bare frame. Also where does the gas Tank bolt on? How hard is it going to be to gut out and still retain all mounting locations?

I have free aluminum and I work on CNC machines for a school job... A great time to knock someting out with my own tooling is before school starts... But problem with the new swing arm is that i wouldn't trust it! I guess I can over engineer it.

Any real advantages to a mono shock?

I like your idea of just extending the stock shock. Mucheasier setup and safety features. I can bolt on the torque plates to the existing dropouts, get them adjusted and at the right length, then have them welded.the bolts I can leave in as extra reinforcement in case of a weld failure

[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 !!!!