RC10Talk - The Net's Largest Vintage R/C Community

EDIT: FFWD to page 2 for latest and greatest of this project

I've been wanting to build an-all trailing arm buggy for a while: as a result of spending too much time on this site, Tanaka's timetunnel and the too-expensive tomahawk a LHS has on the wall.
The arms are too difficult to make one-self without proper tools, so I kinda fridged the idea.
Till I stumbled over this kyosho frame with all the arms but practically no other parts. The perfect cut for me as I planned to replace all else with home-made etc anyway. I paid the BIN.

The arms are practically the only thing I'm sure will be in the final model.
What you see here is a trial: made up with very thin epoxy: no good for racing but easy to work on, cheap too.
The previous trial was sitting on a rc10 sprint chassis of composite craft instead of the original rails.
The next thing I'll try is dual ultima gearboxes, connected by a belt over the topshaft: on the outside like a 4x4MIP.

I don't expect it to run al that well, but I have enough ultimas for running.
This one is for the fun of creating and imagining multiple solutions for all those challenges you meet when there's no manual to follow. I'll try to give you a chance to join in the fun by putting updates here, and of course you can comment; preferably with suggestions

nice project Mr Ed, great minds think alike. I have been working on a similar project using all factory kyosho parts and all period correct. A MIP 4x4 style kyosho scorpion/tomahawke using scorpion and progress parts. Heres a quick mock up. Ive also done a full mockup using kyosho rails the same as you are using but Im going to use a home made chassis like the one in the picture

cool ,
Some friendly competition will raise the bar

I'll take some pics on how I attached the front knuckles.
Should work for you too, and respects your self-set rule of period correct parts also.

Excellent projects guys, I am really looking forward to these taking shape

those projects are great, the 4wd gallop/scorpion is genius.
b.

pics sound good i was going to try ultima axles

that's what I used indeed.

I pushed th axle part through the hole of the arm and and put a self-locking nut on it just tight enough. Then used the type of screw you find on an optima front knuckle: cilindrical base that fits through the ultima axlle hole perfectly and screws into the knuckle.

My major points of worry for making mine 4wd are:
can I get the dogbones to clear the shocks in the front?
can I get the front wide engough to take decent universals (the rear is exaclty at 250mm: the legal limit.

On yours: is the gallop front box the same ratio as the scorpion rear?

the rear gear box I'm using is of a gallop looks very similar to the scorpion box not sure if the gallop and scorpion gear boxes have the same final ratio what steering knuckles did you use

I had never seen a gallop rear box up-close, sorry for the mistake.

Here's some details on the rear and front: as you can see I really had to push the wheels far out to get the tires to clear the arms, and there's still not much clearance. To push them out I used Tamiya optional axles with about 12 mm thick hexes. Not period correct, but that's no prob for me.
What's your plan for tires and wheels?

The dog-bones are standard length ultima bones, so the mounts are further apart than on the scorpion also. All added up the rear got quite a bit larger than the original and I'll need one of those wide CRP front axles to continue this project
Even though I used the same trick with the tamiya axles, the front is way too narrow at the moment: especially when compared to the new rear.

Id like to use modern wheels and tyres like the cars on the time tunnel site. The reason Im using progress/gallop gearbox is because it looks almost identical to the scorpion one.What tamiya model axles are you using, also if you look on the team CRP site they sell a optional ultima front wheel axle which I think might be a little longer which could help with your front track

You mean these axles?
http://www.rcchopshop.com/crp/1713.html
The axle is 5mm so they won't fit through the arm as shown in the picture above.

I have, and used the wider ultima crp axles for the older 2wd front wheels.
But when you use them to put the wheels on, the wheels are offset of the turning axis and kind of swing back or forth when you turn in or out.
Actually the long wheel axles and thick hexes with offset rims make the front wheels in the picture swing a lot too.

I can't imagine the swing motion it's gonna improve handling through the corners so, I was rather thinking of using this one to modify the width: http://www.rcchopshop.com/crp/1707.html
Just have to make up the order still: first making sure there's nothing further I need from them.

Here are the hexes I used: http://www.tamiyausa.com/product/item.php?product-id=53345
they are option parts to the TLO-1 chassis, and so are the wide axles. (I saw them on the shelves just last weekend still, but can't find the nr now)

Maybe I'd better go browsing the timetunnel site again: to check how they manage to put the large 2.2 wheels and tires on without rubbing the rear arms.
(I did already find one other method: put the arms closer together again and find shorter dogbones. Then extend the width at the wheel by using aftermarket wheel axles to widen the TLT-1. They are available in different offsets. I'm keeping it as is for now as I have quite many of the current dogbones in spare.)

Round 2:

well, things got changed around a lot...and this is not the end yet!
Only a kind of retro-active update, round 3 to follow soon.

Stay posted

thats seriously cool.

a bug body would be kinda neat on it imo.

I already tried the bug body for size and it works well, but, it hides the originallity of the car too much.
Anyway, round 3 is already ongoing: The reinforcement of the front section on round 2 didn't feel as strong as it should be.

nice work you love tour ultimz hybrids