Car#3 RC10DS “DragMaster”

[KidAgain]

Here goes the drag racing DS build, gonna be a slow build though still waiting on a bunch of parts and a lot of trial and error.

[KidAgain]

O boy.......................................................

[LoboNYC]

Can't wait to see this project progress and then see it in action

[therigliveson]

This is going to be great!

[KidAgain]

5* castor blocks flipped and modified after a few answered questions this is what we got for mock up

Let’s see how it works out for straight line runs.






Also this is what you need if you want to run Titanium hinge pins on a DS

[KidAgain]

Front end coming together with titanium hinge pins and all aluminum hardware.

4-26 Edit: front inner control arm hinge pin is a 1/2 millimeter short so you have to lightly shave the front outer pad on the control arm, no biggie didn’t take much off to be concerned.

[LoboNYC]

Front end is looking sharp!

Good info on the alternative titanium hinge pins!.

[KidAgain]

Mocking up the TrackMaster trans picked up a few more aluminum screws and ball cups to finish some of the suspension and steering.....











Going to send out the gears, shaft and pin to get Cryo treatment before I slap the transmission back together. I need this thing to hold up to brushless 540-550 can motors in the 2.5-4.5t or 7700kv

[NomadRacer]

Sharp looking! I've been looking at your ball studs, what did you use?

[Phin]

Looking at the front end I'm concerned you might face an issue with bump steer. The extra caster lowered the bullstud on the steering knuckle which is going to put the tie rods at an awkward angle. Also the DS used different steering knuckles which didn't have the ball stud as far back as the buggy inline axles. It looks like the wheels are going to want to toe in as the arm compresses.

You might need to reduce the caster and then go with the DS trailing steering blocks to get some of the same caster effect.


Also, as I mentioned in your other thread, I really do think you're going to have belt slippage problems running that much power through the Trackmaster trans. Genuinely I think you'd be better served by a Stealth trans with a slipper eliminator, and aluminum gears from DHawk. The Stealth will likely be better than any kind of direct drive trans too, as a DD trans will raise the outdrives, which combined with the short DS rear arms is going to cause another awkward angle problem...this time with the drive shafts.

[KidAgain]

Phin should I be so concerned about what you explained on a car that will be going straight? Can I raise the ball cups on the arms a couple mm's?

The transmission I think im just going to give it a go and see what happens same with the DD J-car trans. I have enough options to try a few things, your stealth idea would be my last resort bud. I really appreciate all the input guys.

Nomad the ball cups are ASC4447......... the 4 ball cups on the steering rack have to be cut down.

Phin how do the lower tie rods look installed?

[Phin]

Phin should I be so concerned about what you explained on a car that will be going straight? Can I raise the ball cups on the arms a couple mm's?

Definitely...because if you have bump steer the car won't go straight. Bump steer will involuntarily turn the wheels as the suspension works which will obviously turn the car. It'll defeat any benefit you gained from the extra caster you added.

Move the arms and see if the front axles want to turn at all. If the axles turn that's bump steer. While you're at it check how your camber changes. You'll want your front tires to stay flat to keep the car straight.


When guys used to flip their caster blocks like you did, they also bent the arms on the steering knuckle up to raise the ball studs. This was on the original RC10 steering knuckles though, which were less rigid than the Worlds inline knuckles. Just adding spacers to raise the ball studs may or may not help. What I mean by that is while you're raising the ball studs up you also end up moving them back. It's trading one possibly bad tie rod angle for another. One thought might be to drill a new hole for the ball stud further up on the knuckle. That could raise and straighten out the steering tie rods some. You will lose some Ackermann steering but drag cars don't need that anyway.


There's a good reason RC drag cars use simple beam front suspension instead of a-arms. Beams eliminate 90% of the stuff that makes a-arms better at handling and keep only what helps your car go straight.

[jwscab]

I would definitely spring the front end to be super hard. You could also just place a tie rod up front rather than a shock. Then you would remove all of the handling problems phin is talking about. All your suspension would be in the tire sidewall.

I don't know how I feel about the belt trans. If it's known to skip, it sounds like the wrong application, and you will have less driveline friction going to gears or even a chain drive.

[KidAgain]

Wow guys keep the info coming good stuff.

Phin I’ll take a quick video of the steering travel left to right before I do anything you suggested.

jwscab the class I’m going to run requires 4 shocks 2s and rubber tires but I am going to run limiters to limit travel. I’ve also decided not to use the beltdrive and try the J-car DD.

[jwscab]

Good call on the jcar. If you have to run shocks, definitely limit travel and run some stiff dampening and spring rate up front. You will have to watch your rear travel due to a high outdrive as phin mentioned.