yokomo twin-star hybrid

[Mr. ED]

After having an excellent time at a big race with my yokomo blackdog project I decided to take this car a couple steps further for this years event.
I actually broke the front drive belt and raced most of the second day in rear wheel drive only (with the diff totally loosened up but the driveshafts still in place). the difference between the 4WD and 2WD was barely noticeable on the artificial grass. (It was more like a kind of carpet really; I think called 'astroturf?)

So I subscribed in 2X4 this year and will race a training race next weekend. (Actually I didn't get the car ready in time for the December practise )

Besides turning it into a real 2WD I also wanted to add a new look and stole the cage and body from my hot-shot ultima, and while at it, I took the works shocks back too.
Not entirely happy with the high position of the body using the original top deck and front gearcasing of the yokomo, I then also castrated my nib academy griffin-pro: stole the entire front end... added some optima parts, tamiya M-chassis axles and trimmed the new lazer ZX5 rims to accept narrow front tires.
The rear features academy wheels, mixed and matched CVD parts from a lazer ZX5 and some modern Tamiya's rear arms.
Oh, yes, the driver is a heavily amputated rc10 driver. And to keep it alltogether, I fabricated a 2 part topdeck from an old chassis. It steps down in front of the battery and lets the body sink further.

Any questions, just shout.

[vintage racer]

I really like it,nothing out there similar to that.I love these type of projects.Well done mr.ed,I hope you can remember in time all the different parts you have used incase you need replacements .

[jooles]

Hello,

this one looks really nice! Would it be possible to have some pics of the chassis?

Julien

[Mr. ED]

Thanks James,
Jules , I'm watching the late night movie now, but will take pics tomorrow (the commercials break's just too short for that)

[m_vice]

Sh#$% Mr. ED, when you decide to go for it YOU GO FOR IT. I love it, looks so cool.
is that the hotshot body you had on a Ultima before? or modified Ultima?

I like it a lot, did you take it to the track? let us know how it performs... take some good naked shots please...

[Mr. ED]

Thanks Miguel.
There's not really much visible even with the body off, but here you go:


side view: the ESC is heavy and sits a little higher than I hoped for, but it was this or raising the body. I opted for this as it also provides good cooling. Everything sits nice and tight on the middleline too.


The FRP chassis of the hotdog was trimmed and shortened. 5 screws hold the lower section of the academy front in place.


The steering comes from the same academy car but still interferes with the upper turnbuckles under some suspension-steering action. Bummer.


To allow clearance for the Tamiya arms in the rear (which added a lot of wheelbase and some toe-in) I had to go one tooth down on the pinion and several on the spur. Doing so I could maintain the gearratio I had before, but move the moter forward. Now it's squeezed between the cage mounts and rear arms=no change of ratio possible at all.


The front would be easy to bring into spec by replacing this assembly by some ultima RB5 parts, but I'd rather keep this setup which reduced the steering axle angle. (inversed the c-carriers as done on oval converions)


On 24 January it will go to the track. I hope it can stand up to the abuse because there are plenty high jumps and the tracks surface is very very hard.
I'll also have to check with the race organziers as it's not within legal dimensions: about 5 to 10mm too wide both in front and back.

Overall I started it out to have a fun racer: with mid moter, slipper, beltdrive and the moter on the 'good' side, and the bodychoice acentuating the fun. But I'll probably split it up again later: turn this into a pure fun (maybe even back to 4WD) and start a new built for the racer.
There's just too many things that only just fitted and I've got about zero ease in maintenance and near zero tuneability. (And then there's the issue of the oversized width, maybe even wheelbase too...)

oops nearly forgot; yes this is the same body that was on the turbo ultima chassis before. There was nothing wrong with that built, but the blackdog project car did so well on this track last year that I really wanted to use that as a base... and I didn't have a second hotshot cage and body And while it wasn't complete anymore I also robbed the black- white and red shocks from that ultima. They are really identical to option house gold shocks apart from the plastic parts.

[jooles]

Thanks for the pics! This is a very nice job indeed. The car is looking really good, even without body

Ju

[bearrickster]

nice job, I dont know if I would have cut up that new car. ( I guess I am jellous because I couldnt get one) really it looks like a Hot Shot on Steroids

[Mr. ED]

Well Rick, I got 2 of them, but more important I did not cut up any part of it, just used parts without modication. So I could basically rob this car of its front end should I break something on the standard built. (Actually I have the truck and a spare set of arms and UJ-s aswell)
Ofcourse I won't be able to restore the kit to NIB, but NIB's not my cup of tea anyway.

The other griffin pro is here: http://www.rc10talk.com/viewtopic.php?f=33&t=12587
And the RT sport is here: stupid search engine, I can not even find my own old posts

[m_vice]

Nice,
What are the battery straps you are using? look a bit like the MRP on my Pro-110.
I don’t remember what shock s you used on the T Ultima, MIP?

nice work.

[bearrickster]

I remember It I would have bought two of them if he would have shipped to the US. but I cant find the link anymore.

[Mr. ED]

No battery straps: there're 4 oval slots to pass tape under the chassis: just original hot dog design.
The shocks are yokomo works '91 etc. originals, except for the red springs.

Rick, they are all sold out on the pro version now. Here's the link to academys webpage on the griffin pro:
http://academy-europe.de/logos/rchtm/griffin_pro_rt/1566.htm
and the other car I got in this series: RT sport: just longer arms, bigger wheels and tires and a truck body
http://academy-europe.de/logos/rchtm/griffin_pro_rt/1582.htm

[Mr. ED]

A week has passed since the race last Sunday and I haven't received the action pictures of my car yet from the guy who was friendly enough to make some with his own superior camera. So you'll just hace to do with my blabbering in this sole picture of the dismantled top deck.


The race started of badly for me: got to the startline for the first heat, turned on the radio and the car started acting up as if the crystal was gone.

I switched to another frequency for the second heat, and added the double side tape on the front portion of the ESC as seen in the picture (I suspected the setup button might get pressed against the topdeck). Unfortunately neither modifications did much good: I got of the startline ok but at the first passage near the driver stand my steering just went full lock left and did that every time I hit the gas. Heat over for me, again.

A new receiver went in after I remembered I had trimmed the 1.5 m antenna of the aircraft receiver. I knew it is risky to shorten an antenna wire, but it tested ok when I was alone. I guess I can't use it anymore near other radios

With the new receiver I could finally run in heat 3 and , boy, I then realized how badly I was out of practise. 9 turns in 6 minutes. But at least I had a qualifier and made it to the finals (series D; the lowest of the lowest in this race )
We ran 3 finals and I improved my result with 1 turn every time. In the end my best run was only 20 seconds worse than asso-mans best run.
I was really thrilled with how the car handled and the result I got, especially considering Asso-man was running his old-new RC10 with Lipo and brushless, while I'm still on Ni-mh and a 18 quad brushed.
Over the entire day nothing broke (except a ball-end that popped of the turnbuckle near the end of my last round, and I managed to get it over the finish line).
The steering was a bit weak (the servo saver is just too soft) and the car nose-dived a bit in the corners. Got rid of the diving by removing a collar on the back shocks and that was the only modification I had to make over the whole day (aside of the receiver replacement).

Another week and then it's time for a 2-day race at the same track. I'm all up and ready for it. Going to give it my best shot, don't change anything to the car and concentrate on my driving. I've never been a great pilote, but with the practise and this car , I hope to pût another turn (or 2) on top of my best time.
Whish me luck

[m_vice]

Good Luck man. It is all about practice and set up.
keep the stories coming.

[Mr. ED]

I've been racing with varying regularity for over 20 years now and know I will never be a top racer. But a good car like this one sure makes a lot of difference.
If you have little practise it's a must to get a car to work well right from the first qualifier: so you have 3 times 5 or 6 minutes to get back in the routine a bit, watch out for other cars, look for the fastest track etc. . If you need all 3 qualifiers (as I often did in the past) to get the car to run descent, you can only really start picking up with your faded driving skill in the finals= too late.

Glad you like the report, I hope to add some pics to it soon.