Proper Optima Mid Slipper Clutch

[mr. ed]

break a leg

[alcyon]

Originally Posted by mr. ed

break a leg

just came back from the track, it was hot all day but it rained all night last night, so i thought the track would dry out, i was horrified to find it submerged with water about an inch high.. 80% of the track ! so i tested the car in an open grass and sand field. the car was really fast but a lack of slipper made it diffcult to stab the throttle from low speed, so i have to the feather the throttle in the corner and when the car straigthens out gas it all the way.. did find my optima mid reliable though, it was traction rolling crazy too, so much grip. here is a pic of my turbo optima mid SP.

[mr. ed]

Nice hop-ups you got onthere. How about some body-off shots?
I'm building a one-off with long wheelbase and lazer suspension too.
At the moment it sits on a lazer 'sport?' chassis: the kelron one. I like that one 'cause it's much wider to accomodate saddle pack lipo's and has no holes in the bottom. But ofcourse it needs stiffening... a lot. Right now it kind of feels like I have a tad too much tension on the belt when all is flat out.

[alcyon]

here they are my friend.
Lazer ZX suspension, James Instone Lazer ZX Fibrelyte shock towers, self modified original battery holdowns for lipo saddles. Original kyosho Graphite chassis from LWB conversion. Ball diffs front and rear. i am thinking of changing to gar diffs cause they need much much less maintenance, and i beleive they will work well with the slipper clutch.

[mr. ed]

Cool but you need to clean up the cabling a bit
Which moterplate is that?
I have the kyosho optional one for the TF1 which fits and has the same style cooling ribs, but doesn't work with the gearcover.
Do you feel the belt covers are really needed? I only have the short ones to install and was hoping to go with a bellypan but no belt covers

[alcyon]

Originally Posted by mr. ed

Cool but you need to clean up the cabling a bit
Which moterplate is that?
I have the kyosho optional one for the TF1 which fits and has the same style cooling ribs, but doesn't work with the gearcover.
Do you feel the belt covers are really needed? I only have the short ones to install and was hoping to go with a bellypan but no belt covers

its difficult to tidy up with brushless cause theres just so many cables. anyway, you must have all belt covers on this car. Just a small amount entering the gearbox is enough to destroy the gears. the undertray helps a lot but still some pebbles will get in. the motor plate is A & L one i think from the 80's. so is the bellcrank. i bought the car used from my friend and it had those hop ups on it. i suggest you chuck the flexy kelron and get at least the aluminium LWB chassis. I used to have a kelron self made chassis and the damn thing flexed even by just the servo pulling on the bellcranks ! hmm, by the TF1, you mean the EP spider, optima mid based touring car from 1995 ? by the way, where are you from and how old are you. i am 35 and been into rc since 1990.

[mr. ed]

Yes, the A&L steering was easy enough to recognize. I had forgotten they also made a moterplate for the optima mid and not only for their lethal weapon transmissions.
I'm 38 and live in Belgium. I got my first car: a boomerang in the year it was released. I think it was for saint-nicolas so I guess I'm celebrating my (24th?) RC anniversary on tuesday.
Yep the original spider. I was given this one after a friend got his TF-2. I'm surised you know it: somehow very few people seem aware of the existence of Kyosho's first narrow tourer.
Don't worry about the Kelron: I'm not counting on that for rigidity, it'll just serve as mounting space for the electronics and saddle pack.

[alcyon]

Originally Posted by mr. ed

Yes, the A&L steering was easy enough to recognize. I had forgotten they also made a moterplate for the optima mid and not only for their lethal weapon transmissions.
I'm 38 and live in Belgium. I got my first car: a boomerang in the year it was released. I think it was for saint-nicolas so I guess I'm celebrating my (24th?) RC anniversary on tuesday.
Yep the original spider. I was given this one after a friend got his TF-2. I'm surised you know it: somehow very few people seem aware of the existence of Kyosho's first narrow tourer.
Don't worry about the Kelron: I'm not counting on that for rigidity, it'll just serve as mounting space for the electronics and saddle pack.

the reason i knew about it was a kit came to my local hobby shop in 1995, and when i saw it i iimediatley recognised it was an optima mid with short arms! it came with a 94 celica body, on the box art it was painted silver. also 1995 rc car action made a shooutout between all the tourers of that time and this was included. frank masi commented how much he loved the optima mid, and kyosho brought it back as a bitching tourer...

[alcyon]

got my shaft back from the machinist, i am still not happy with the tolerances both inside the gearbox and outside. The spur gear now can move up and down a bit, and i had to install a spacer to hold the b4 plate properly, and i need to extend the screwing side by 1mm. otherwise everything looks great and seems to work fine. a push test confirms the smoothness of the spur and pinion, it was noticably wayy quieter than the original mids spur and pinion mesh. will be testing the car this saturday.
Merry christmas everyone !

[kek23k]

Thanks for posting pics of your mid, sure brings back some memories. I used to use that shell on my Lazer too x

[alcyon]

i am glad to report that the slipper seems to work well, a test in my house shows the slipper is silent and slips consistently. i am charging 3 saddles now and will be taking a 3 pack spin later this evening if it doesnt rain.

[Stretch]

Having run an Optima mid briefly in the late 80's (nice selection of extras btw), it sounds like your problems are due mostly to the huge increase in power that LiPo/brushless is giving you over what the car was designed for. An insanely hot motor back then was a 10-turn, and would probably be a triple or quad-wind to tone the torque down to something manageable. Additionally, in order to make the batteries last 5+ minutes, it was necessary to let the car roll through the corners power off, then pick the throttle up gently on the exit so as not to take too much out of the cells. Ah, the joys of racing with 1700mAh cells...

[alcyon]

Originally Posted by Stretch

Having run an Optima mid briefly in the late 80's (nice selection of extras btw), it sounds like your problems are due mostly to the huge increase in power that LiPo/brushless is giving you over what the car was designed for. An insanely hot motor back then was a 10-turn, and would probably be a triple or quad-wind to tone the torque down to something manageable. Additionally, in order to make the batteries last 5+ minutes, it was necessary to let the car roll through the corners power off, then pick the throttle up gently on the exit so as not to take too much out of the cells. Ah, the joys of racing with 1700mAh cells...

i guess so, but the rc10 at the time did have a working and better slipper clutch didnt it? even back then, compared to the zx-r, the mid wasnt as easy to drive, simply becuase the lazer had a better and more consistent slipper. i just tested the car an hour ago and i am very glad to inform that the slipper works VERY well. The setting is consistent until the battery is out, and never once did the pad or spur burn out like it did when i tried to let the original OT-88 slip a lot. The car was VERY much easier to drive. setting a slipper is a compromise between the high traction and low traction conditions, so i set the slipper for the high traction area of the track, otherwise the car will not have enough speed to clear the jumps. but at the low traction loose sand area, i had to feather the trottle to prevent wheelspin. The car is so much more easier to drive. In the high traction section i stab the throttle in the corners and yet there is no wheelspin at all! i also took huge jumps many many times and the slipper "slipped" and protected the internal gears. I did install pargu2000s aluminium center gear with new OT-86 counter gear and new SG-25 sprocket, and the car is super smooth. Hard landings were quiet too, testament of the protection it provided the internal gears. i am glad to say i am ready to mass produce this shaft, with minor tweaks to make it better. Video is coming soon. Merry christmas and Happy New Year to everyone!

[Stretch]

The RC10 - being 2wd - needed a slipper even in the late 1980s just to stop it back-flipping. And blowing the gearbox.

Also, the tracks of the day tended not to feature jumps sized for motocross.

The ZX-R came out some time after the Optima Mid, so I should hope it was an improvement...

[alcyon]

Originally Posted by Stretch

The RC10 - being 2wd - needed a slipper even in the late 1980s just to stop it back-flipping. And blowing the gearbox.

Also, the tracks of the day tended not to feature jumps sized for motocross.

The ZX-R came out some time after the Optima Mid, so I should hope it was an improvement...

by the way how did you choose your nick? does it have anyhting to do with the optima mid stretch ?

[adam lancia]

@alcyon: nice work there! Once you're happy with the tolerances, would you consider getting another couple of these made? If so, I'd be interested in 2 of them anyways, maybe 4. Pm me when you have a chance, thanks!

[alcyon]

Originally Posted by adam lancia

@alcyon: nice work there! Once you're happy with the tolerances, would you consider getting another couple of these made? If so, I'd be interested in 2 of them anyways, maybe 4. Pm me when you have a chance, thanks!

yes adam, it would be great if all who want these let me know in this forum so that i can make all the necesary quantities, that way it will bring down the cost. i will make a video showing my car in action with the slipper and then you be the judge !

[Stretch]

Originally Posted by alcyon

by the way how did you choose your nick? does it have anyhting to do with the optima mid stretch ?

I did run a long wheelbase chassis for a couple of meetings, but the nick had already been applied...

[offroad170]

hi i just noticed your board while looking for an lrp x12,nosram or similar i have been building buggies for about a year now in all my collecting i came across a brand new optima mid(se or turbo not sure,gold shocks)hardly any wear on original tyres in a friends loft,it still has the original spur,pinion&slipper i like the way the drive system is fully encased.i ran it for a few days then took it apart but its all still there just mixed in with other parts,i'll sort some pictures if your interested we could do a swap for parts or come to some arrangement would be nice to see it get a good home.offroad170/B44.1,catsx2,xray 808.

[alcyon]

http://www.youtube.com/watch?v=YdBUdcm15Xg
my latest video