Cool But Not Perfect, Yet

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Cool But Not Perfect, Yet; fixing the engineering flaws
Topic Started: Dec 22 2007, 02:29 PM (4,419 Views)
alaskadf300	Dec 22 2007, 02:29 PM Post #1
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	Hello all, I had always wanted to get a Kyosho Blizzard and I finally did in late November. The first things that I noticed were what I considered to be engineering flaws (cost cutting/manufacturing shortcuts). I knew that It would need a one-piece aluminum belly pan, and that would mean ditching the plate that connects the side-plates and holds the motor and servos. It also seemed ridiculous to have the diff sticking out of a large hole exposing the brakes to moisture. I plan to shave that area of the diff flat where it nears the belly-pan. The wheel mounts also experience only upward forces, yet Kyosho has the mounting screws at the top, giving those forces leverage to snap them off when jumping. I'm planning to scrap the wire-springs and thereby use the larger lowermost hole as a second screw mount. Some coil/pull springs will provide suspension, this will also plug another set of holes in the chassis. Next, I'm building a plexiglass cover that keeps all snow from entering through the top. after I get all the cutting and fitting finished, the bare chassis will get sealant and leak testing. I am running regular bearings inside and stainless for the wheels. The ladder chains are also going stainless once I get them ordered from Halebros. One major challenge is figuring out how to fit bearings to the main drive sprockets, If I can't install bearings, it will eventually get new side-plates and my own design for direct-drive. BTW, I shall try to post pics of my modified chassis later today.
	"Rule #1, Never Run It where People Walk Dogs!"


alaskadf300	Dec 22 2007, 02:58 PM Post #2
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	Additionally, I must say that "outcastrc" and "magnum" have been quite inspirational from the very beginning, thanks guys!. I already have a bottle of OFNA diff-lock 120,000wt. ready to go and I'm making brake pads very soon.
	"Rule #1, Never Run It where People Walk Dogs!"


alaskadf300	Dec 22 2007, 03:59 PM Post #3
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	I almost forgot, has anyone thought about the use of O-rings (if they could be made to fit) in the differential?, I mean to keep the silicone oil from getting to the greased gears. And for grease, I have chosen to use Amsoil synthetic EP grease NLGI #1.
	"Rule #1, Never Run It where People Walk Dogs!"


alaskadf300	Dec 22 2007, 08:54 PM Post #4
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	Here are the barest of beginnings, more madness will follow as soon as I can complete more work.
	"Rule #1, Never Run It where People Walk Dogs!"


zenmasterzoso	Dec 23 2007, 05:17 PM Post #5
Worthy of the Trax! Posts: 38 Group: Member Member #608 Joined: December 7, 2007	Nice job , If I were you I would keep going with the aluminum on the sides also.Please post updates, sounds like it will be worth the effort.



alaskadf300	Dec 23 2007, 05:27 PM Post #6
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	Thanks, I probably will do just that eventually. I am working out the mounting setup for the pull-spring suspension right now. Also, I wonder how formica would behave as a brake-pad material, I may just get the gasket composite to start with. This is a fun and challenging project so far, but visions of a monsterous scratch-built 50mph snowcat are already invading my mind.
	"Rule #1, Never Run It where People Walk Dogs!"


zenmasterzoso	Dec 23 2007, 08:45 PM Post #7
Worthy of the Trax! Posts: 38 Group: Member Member #608 Joined: December 7, 2007	Now a 50 mph Snow Beast would be cool I applied gasket material brake pads and ended up removing them.I may try the Ofna Jammin Brake shoe retrofit, but personally i didnt have success with the particular Gasket material i used.



outcastrc	Dec 23 2007, 10:00 PM Post #8
Administrator Posts: 1,150 Group: Admin Member #1 Joined: December 13, 2005	Sounds like an awesome modification to watch. Can't wait to see whats next...



alaskadf300	Dec 24 2007, 07:21 PM Post #9
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	Here is what's next, although it's only a small thing. I'm still sourcing the SS torsion springs that will slip over the arms. Using simple pull-springs didn't look as slick. Hopefully I can shave the diff and cut the plexiglass for the lid later tonight. The hardware that is outside the chassis is all SS.
	"Rule #1, Never Run It where People Walk Dogs!"


AST	Dec 25 2007, 09:42 PM Post #10
Swayed by the Trax Posts: 12 Group: Member Member #268 Joined: May 27, 2007	please keep us posted, man..nice job i do not like the suspension either, i have replaced those rubber washers with springs..it works well if it is not toooo cold cause otherwise, the spring will be frozen and coverd by snow and thus loses its elasticity.....



bRIBEGuy	Dec 28 2007, 08:43 AM Post #11
Swayed by the Trax Posts: 18 Group: Member Member #151 Joined: December 19, 2006	Lookin' good so far.



alaskadf300	Dec 28 2007, 06:58 PM Post #12
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	Thanks guys!, I'm encouraged by the kind words. The hard thing right now is getting the diff to fit without cutting my belly pan, I'll cut the diff housing and peen the belly to clear the exposed ring gear if that's what it takes. I also really want to place the steering servo up front so I can use the rear half of the chassis to mount batteries, ESC, and RX. Has anyone considered running the diff pinion right off the motor?.
	"Rule #1, Never Run It where People Walk Dogs!"


outcastrc	Dec 28 2007, 10:00 PM Post #13
Administrator Posts: 1,150 Group: Admin Member #1 Joined: December 13, 2005	You'd need to be running some serious power to compensate for the loss of reduction. I can't gear my setup up enough running dual motors. But I don't think I have the power to just get rid of the spur gear either...



alaskadf300	Dec 28 2007, 10:18 PM Post #14
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	So if I go to limit on the motor with a big $ lipo/brushless setup, it might work?. I will have a snowproof chassis, so why not. There must be a mathematical equation for the RPM/workload/runtime somewhere on the net. My main concern would be the front drive sprocket bolts, diff, and chains. If you have the reduction in the diff plus further reduction at the chains, it's worth a try.
	"Rule #1, Never Run It where People Walk Dogs!"


alaskadf300	Dec 29 2007, 11:16 AM Post #15
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	I filled the spider-gears with 120,000wt last night, following Outcast's directions to the letter and it feels perfect. One other thing I did was to smooth the mating surface with 2500 grit sand paper and slightly chamfer it allowing me to squeeze an o-ring into that gap between ring-gear teeth and cup. I'm going to let it sit and see if it leaks, I doubt that it could. The ring-gear now clears the belly-pan thanks to a small depression I made with clamping pressure. I need to find/build a motor-shaft to pinion adapter and fab a new motor plate today. One advantage to mounting the motor directly will be heat dissipation, it sits right on the belly-pan, and that pan will stay pretty cool out in the snow.
	"Rule #1, Never Run It where People Walk Dogs!"


alaskadf300	Dec 31 2007, 12:47 AM Post #16
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	Ok, I made brake pads out of black formica for a first try material test. I'm still pondering the gearing it will have. If I am running a 19T orion V2 and the diff has 37T/11T gearing, and the chains are 18T/12T, would this mean it equals 55T/23T-4.86:1 final drive?. If it does, will this allow my motor to operate without frying?. Please help if you have any info/opinions.
	"Rule #1, Never Run It where People Walk Dogs!"


alaskadf300	Jan 1 2008, 09:59 AM Post #17
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	After doing numerous computations, it still comes out the same. If you count the diff pinion/ring gears as the "gear ratio", it equals 3.3636. The chains come out to 1.50 giving a final drive ratio with a 1.26in. wheel dia. of 5.0454. This means that the tire(or in this case, sprocket)/gearing ratio is -1.087, that's on the torque side of near ideal. It could be that the stock gearing of 25.5:1 is one of the reasons that the silver can motors get so hot.
	"Rule #1, Never Run It where People Walk Dogs!"


alaskadf300	Jan 1 2008, 06:40 PM Post #18
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	A couple of problems have come up. While most folks probably just fill the diff with 120,000wt and button things back up, I left it in a bag to see what it would do....it leaks over time. Also, if you check you will notice that the "white metal" sleeves that fit nicely to connect the spur/pinion drive line are not fitting right with spider-gear shafts. They are cut too deep by a mm or so on those two shafts, but Im going to make shims to get rid of the excess play.
	"Rule #1, Never Run It where People Walk Dogs!"


AST	Jan 1 2008, 08:05 PM Post #19
Swayed by the Trax Posts: 12 Group: Member Member #268 Joined: May 27, 2007	can anyone please explain to me how could a big pinion will fry your ESC?...i have just installed a 32t pinion made for 1/10 pan cars...my blizzard now runs almost twice as fast as it does before......so..why could a big pinion fry your car?...the motor's RPM is fixed at certain voltage....say..if you are using a 7.2v pack and your motor is running at 2000rpm...dispite the size of your pinion, your motor is still running at 2000rpm....i just dunt get it...thansk...



AST	Jan 1 2008, 08:08 PM Post #20
Swayed by the Trax Posts: 12 Group: Member Member #268 Joined: May 27, 2007	even the 120k ofna oil will leak..the best option is to install the option part FZW18..which is an o ring sealed full diff set...then..you can pour diff oil from 3000k-120k in it.....but the price is OMG.....somewhere around 80 bucks....



alaskadf300	Jan 2 2008, 12:09 AM Post #21
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	On the gearing, anytime you dramatically up the gearing, there will be a greater amperage draw to overcome the increased rolling resistance. It would depend on what motor/batt/esc plus overall drivetrain friction. About those steel gears, I must get them!, not because it's needed, just because they exist. Thanks for the part #.
	"Rule #1, Never Run It where People Walk Dogs!"


zenmasterzoso	Jan 2 2008, 07:05 AM Post #22
Worthy of the Trax! Posts: 38 Group: Member Member #608 Joined: December 7, 2007	AST Jan 1 2008, 08:08 PM even the 120k ofna oil will leak..the best option is to install the option part FZW18..which is an o ring sealed full diff set...then..you can pour diff oil from 3000k-120k in it.....but the price is OMG.....somewhere around 80 bucks.... I used 100,000 and have yet to have a drop leak out after approx 10 -15 battery run through it? My guess is each unit may have slight differences in how they fit , also mine only had a few runs on it when i filled it , possibly a more used and slightly worn system could result in leakage? As for spending $80.00 on sealed diffs , thats wasted money ,a tube of diff oil is 5 bucks and it takes 5 mins to refill, just my thought. good luck



outcastrc	Jan 2 2008, 09:07 AM Post #23
Administrator Posts: 1,150 Group: Admin Member #1 Joined: December 13, 2005	I used a new diff as well when I did mine. I should pull it out and check but a year later the diff still feels good. As far as gearing you can gear it up to the moon if you you have no rolling resistance. When I run my Bliz on hard pack everything stayed cool. but run a full out pack thru 6" powder and the motor was boiling hot (in a stock setup) I have a spreadsheet made up for my crawling projects. I never tried a blizzard in it but it wouldn't be a problem to try it... If I get a chance I'll start a thread for it.



alaskadf300	Jan 2 2008, 07:41 PM Post #24
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	Hmmm, mine is indeed brand new and it leaks, that is unfortunate. I'll just use heavy grease I guess. The powder snow is a factor since I plan to mostly run between 18F and 32F and my backyard is usually fresh powder. I'm planning to start putting together my spring loaded chain tensioners later tonight. Steel gears may seem like a waste of money, but down the road when I go large brushless, they will add greater long term durability.
	"Rule #1, Never Run It where People Walk Dogs!"


alaskadf300	Jan 13 2008, 09:31 PM Post #25
Making Trax! Posts: 117 Group: Member Member #581 Joined: November 27, 2007	Here are some more alterations, the first one is a rework of the rear stabilizer arms. This gives massive travel and the ability to easily remove the tracks in seconds with no tools. The only drawback is that the rear wheel must be adjusted slightly above the others to keep the rod out of the track.
	"Rule #1, Never Run It where People Walk Dogs!"


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