Optima Mid Runner (Almost Done, New Arms installed)
 

Hi all, first post here. I figured I would post some pics of the Optima Mid project I am currently working on. I started with a rough Optima Mid for a really great price locally. As i started digging into the car I realized even though the car looked rough, it was actually in pretty decent shape.

My plan with this car is to run it so there were some things I needed to do. First was to add a slipper clutch to the car. I machined a new top shaft for the car with allowed me to run a slipper assembly from an AE B4. I also used the B4 gear cover by drilling and tapping a new hole for the top 3mm screw.

I ordered new universal swing shafts, 68mm for the front and 62.5mm for the rear. A friend of mine gave me a set or Lazer ZX-R arms to get measurements from and I will be machining new arms for the car, the same length as the ZX-R arms.

I ordered ZX-5 rear hubs, front carriers, steering arms and wheels. After mocking up the car, I will end up with the proper track width between the front and rear tires using the new wheels with different offsets.

I added a LWB chassis and machined a new upper brace, lipos cradles, wing mounts, and wing buttons. Once I get my arms machined, I should be able to get the final assembly done. I hope to finish the car in about two weeks.

Enjoy the pics.

Jake

http://i3.photobucket.com/albums/y75...d/IMG_3175.jpg
http://i3.photobucket.com/albums/y75...d/IMG_3179.jpg
http://i3.photobucket.com/albums/y75...d/IMG_3178.jpg
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http://i3.photobucket.com/albums/y75...d/IMG_3196.jpg
http://i3.photobucket.com/albums/y75...d/IMG_3197.jpg
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http://i3.photobucket.com/albums/y75...z/Untitled.jpg

Wow

Nice work!

Are you able to get arms machined out of aluminium?

That is fantastic work.

Any possibility that the top shaft and Lipo holders might be made in small numbers?

Would definately buy them here!

I made a few of the top shafts and selling on eBay.

The arms are actually being milled from Nylon 6/6 but could be milled from aluminum if I had the material.

I still have some of the material for the lipo cradles as well.

Hopefully, I can get the car finished in the next couple weeks. I just had my new wheel shafts delivered today and all I need to do now is rebuild the front shocks, and wait until next week to machine the arms.

I have access to a CNC mill but I have to travel to use the machine.

Thanks guys

Jake

Some great work going on there. It's great when vintage cars get new life breathed into them with a mix of old and new gear. I take it you have seen Luke's Procat? Mine is similar and on the Schumacher website under the vintage section :thumbsup:

You did some great work Jake :thumbsup:

so you are the one who has been selling the B4 top shaft for the mid on ebay. i made one about 6 months back too but mine is one piece. I see you are using MPP LAZER arms, same one i am using. Unfortunately these arms seem to flex noticably. However they should not be easy to break. so far mine holds up fine. i am however getting fed up with the Mid as i always seem to find sand in the gearbox no matter how hard i try to seal the drive train. i run on extremely dusty and sandy tracks so the sand is very fine. However the good thing about the mid is with the use of the aluminium chassis, its practically unbreakable. i have thought of going to my Lazer ZX but i think in few weeks i will probably snap the graphite chassis. i will re seal the drive train one more time and re try again. I just found out that the pargu2000 alloy center gear i installed 8 months back is now chewed up thanks to the sand in the gearbox.. bummer.
oh yes, do read my blog on the optima mid and what changes i put the car through..
http://superturbooptimamidspecialzx-5.blogspot.com/

Kyosho Optima Mid Custom manual
 

Hi guys,

Can somebody help me to find a copy of the Kyosho Optima Mid Custom manual.

Many thanks in advance for your help:thumbsup:
rgds

Try this:

http://www.retromodelisme.com/liste_manuel.html

Nice try but they do not have the Optima Mid Custom manual :cry: I searched for it too recently and asked the same question at http://www.rc10talk.com/viewtopic.php?f=30&t=27466

We may get help there soon by a nice person from France :thumbsup:

/j0pp3

Hi, Many thanks for your reply!
Please let me know once the manual is available!

Your help is much appreciated:)
rgds
Oli

I should have the arms machined today or tomorrow. I took measurements and realized the rear track width was about 1/2 wider then the front. I went ahead and extended the length of the front arms to make up for the difference. This of course forced me to order a pair of the 73mm front swing shafts. Regardless, I will acheive my original plan to run the ZX5 front wheels.

I am running five sets of the lazer arms and four sets of short arms roughly same demensions as the standard Optima Mid with a slightly different design.

Will post pics when they are done.

Can't wait to see them.....:blush:;)

kyosho optima mid custom manual
 

the kyosho optima mid custom manual can be downloaded on that link in a previous thread, but the manual is in japanese.

i've searched a lot of websites and sended emails on other websites but it seems that there is no english version at the moment. very rare item?

hope there is somewhere an english version of that manual!! or if someone can email it and pass it on...

kenios

That manual was actually uploaded today after my request on RC10Talk.com. I have no problem using it as it has the part numbers in the exploded view :wub

/j0pp3

Joel, thanks for your kind effort mate:thumbsup: much appreciated;)

Kyosho optima mid custom manual link
http://www.retromodelisme.com/manuel...om-kyosho.html

dont make your front end too wide, you will not have enough steering.

Not sure what you mean by stating the car wont steer if you widen the front. I don't see how I could have any issues with steering with what I have done.

The arms have been lengthened approximately 1/4 inch on each side which will make up the difference in width.

The rear of the car was approximately 9.500 inches wide and the front was 9.000 inches wide. With the new arms the front track will be 9.500 as well. Pictures tomorrow.

Jake

when your front end is too wide, the car will have a tendency to straighten itself. i faced this with my optima mid with Lazer ZX-R syuspension. i used the wide option on the front, and what happened was even with extremely slow cornering speeds, i cannot make the tight turns of my local track. When i narrowed the front end, i suddenly got noticably more steering. Even internet resources on rc car handling confirms this.

If somebody can help me with this, please let me know!

http://www.oople.com/forums/showthre...342#post672342

thanks

Big progress last week. I finally was able to machine the arms and get the remainder of the parts in to finish the build. I wanted to run the newer ZX5 wheels so i had to make a couple adjustments to the drawings on the arms. I ended up machining the front arms 1/4 wider then the factory ZXR arms, which made up the difference in the different wheel offset. I also ended up running 73mm swing shafts in the front and 62.5mm swing shafdts in the rear.

The factory Kyosho steering was cracked so I needed to figure out a way to make the car steer. After looking at the RC10 Worlds car steering I had at the house, I went ahead and machined new posts so i could have the ball bearing steering in this car. Works great but I am not getting full lock on the outside tire when turning. I may need to find some different bellcranks.

I fired the car up today and it runs really well. The B4 slipper works flawless and I am surprised how quiet this car runs. I need to take the car aprt and clean everything for the final assembly. There are a handful of things I am going to replace but nothing major. Will run the car with a boosted 13.5. If it doesn;t run like I want, I have an 8.5 which should be more than enough especially on the track I run on. Hopefully I can get to the track this week for some tuning. I may be able to get some video as well.

Parts Used:
ZX5 Wheels Front and Rear
ZX5 Rear Hubs
ZX5 Front steering arms and Castor Blocks
73mm Swing Shaft (Front)
62.5mm Swing Shafts (Rear)
RC10 Worlds ball Bearing Bell Cranks
Machined LIPO Cradles
Machined Arms
Machined Top Brace
LWB Chassis
SDPSI Belt
Repro Body and Undertray
Jake

http://i3.photobucket.com/albums/y75...d/IMG_3173.jpg
http://i3.photobucket.com/albums/y75...z/IMG_3209.jpg
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Wow, that looks amazing! Where did you get the belt from?

The belt is a true motion belt from SDP-SI. They pretty much have everything you could want from gears to pulleys, to belts.

https://sdp-si.com/eStore/PartDetail...7&GroupID=1022

127 Grooved belt is what I ordered. The only issue you will find is the belt width is 6mm. You must find a way to cut the belt. I made a jig on my lathe which made cutting the belt a breeze.

Jake

WOw interesting find

Sadly I don't really have a way to cut it so I will have to stick with the Kyosho belt

PM sent

Is that rear wing mount something you made yourself? I need something equivalent for one of my projects

I made some changes to the car since the last photos. The wing mount didn't work out the way I expected and I ended up machining a new wing mount from CF. Also the RC10 steering did not have the proper geometry and was not giving the front end full throw. I solved the problem by changing out the steering using an A&L setup. The car turns on a dime and is very controllable. I will be doing some track testing in korea with the car in the up coming months. It should be a decent contender in the current 1/10 4WD class.

Will update the pics very soon.

Jake

Well nice.

I used to race a Mid Custom BITD and yes,they are quiet.

My racing team mate used to call it "The Hush Mobile",quite a revelation
after the Tamiya Boomerang's(my previous racer)screaming gearing.

It didn't want to slow down either,very little drag through the gearing
and belt.

I was able to get the car out to the Yongin Circuit in South Korea. I got to run a few laps with the Mid prior to a vintage race but put it away since I had to get my actual race buggy ready for qualifying. I was pretty happy with the car but it definitely need a bit of tuning.

2nd trip, I had full plans to race the Mid and showed up early to spend some time tuning the car. First two practice sessions went good and was able to get the car to respond properly. Third practice session, the car was running great. Got slightly out of control and hit the triple jump wrong. Crash ended my day by breaking the rear shock tower. due to me being in South Korea, I don't have access to the parts I need. I did not want to waste money on another OEM tower since it is definitely a problem. I am moving back to the US in one week so I will be machining a new shock towers from 5mm CF. That should fix my issues. Next trip to the track I will have video of the car running.

Jake

No more kim-chi for you soon he? I bet you won't miss the smell of that ;)

I never understood why they made the shocktower of the mid in 2 parts. Maybe so you could replace the broken top part quicker :)

Personally I have a bit of mixed feelings over the mids: great looking cars and sturdy enough, good suspension with possibilities to upgrade easily (as you've shown well). But on the other hand; the lack of a slipper is so frustrating, and the mixture of belts and gear-on gear in 1 open gearbox is freightening.

I prefer the yokomo 870C design where you don't need to seal up the belt enitrely. I know the lazer has the same advantage, but somehow I can't get that car together and have it run smooth as the unsoiled mid transmission. So in the end they both sit half-assembled in boxes waiting for a new interest.

Great to hear you got her out for a bit of action
I couldn't tell from the pics but if you haven't already moving to a single piece rear tower will help alot in the strength department

Also, lazer rear towers bolt right up