Tuesday, June 25, 2013

RE-Xtreme RE-DP Typhoon Spec "R"

 OK. Time to checkpoint this plastic bucket of RWD. I call it Spec "R"

I guess there have been a few modifications during the build of this machine.

 So I guess I'll start at the front.

Lower Arm replaced with Wrap up next Y arm TN Racing Extension and Traxxas ball joint.
Upper Arm replaced with TN Racing mount, Custom Upper and Traxxas ball joint
C Hub replaced  with Kazama DRB knuckle (modified)
Kazama Knuckle Kingpin position
   Upper : Inner position 5 
   Lower :  Outer position 2
Dog bones removed.
One way removed.
Gear case modified.
Team Suzuki Type 2 Belcrank steering arms extended with Team Suzuki Damper mounts
Custom Ackerman bar with + 2mm wider mounting point.
Overdose Servo Saver for Tamiya.
SSG Shock Tower.
Aluminium Shock Mount
TN racing Lower shock mount extension
Yokomo SS length Shock
Oil 600
Active Hobby Slow rebound piston
RC 926 hybrid spring.1.3 Soft / Med
RC 926 3mm hub with Alloy Wheel (+15g each) offset +11 (effectively +9)

Front Carpet Tyre Spice HDPE.
Front weight ZERO

Sanwa SRG-BL Brushless Servo 0.8s

Keyence Tachyon ESC with Silver 14G wire.Keyence Luxon KG 7.5T "Street Jam Version" with Active Alloy endbell
HPI Spur 86T
Yokomo Pinion 20T

Short Battery Pack
Side Weight 60g

Yokomo motor mount, modified for spur clearance
Yokomo 4wd input shaft shortened.
Yokomo Strong Solid Axle with Steel End caps and alloy centre.
Yokomo Standard plastic gear set.
Overdose 44/2 rear drive shaft

Active Hobby Link Suspension (including Alloy lower arm)
Yokomo DRB rear knuckle (requires shimming)

SSG Shock Tower.
Aluminium Shock Mount
Lower Ball Joint Shock Mount
Yokomo SS length Shock
Oil 200
Normal Yokomo 3 hole piston
RC 926 hybrid spring.1.3 Soft / Super Soft
RC 926 3mm hub with Alloy Wheel (+15g each) offset +11 (effectively +9)

Rear Carpet Tyre: En Route

Rear Weight 250g
Street Jam OTAR31 Rear Diffuser.

I'm debating a carbon chassis at the moment but I'm actually pretty happy with how this plastic bucket functions. To upgrade the remaining plastic components would cost about $620. I think that's a bit much.
Total spend to date has been around $300 for the rolling chassis only. Most upgrade parts were already purchased on a second hand chassis.

So I guess this is the final spec for a while. It's functional.

the 2 main things for Rear Wheel drive are front steering speed and rear traction.

As you can see, the steering angle is ... enough.

In both directions.

Steering speed is very fast. It is hard to be pin point accurate with out a gyro. This is the main reason I will install a gyro in the future. It will make it smoother.

As you'd expect with ball joints on upper and lower arms, geometry isn't exactly perfect. There is a lot of play in the setup.

Castor is around 8~10 degrees.
Camber is around 10 degrees when running straight. These Spice tyres accept generous camber.
Toe is close to Zero.

Rear Link suspension creates less camber under squat conditions and tries to take advantage of chassis roll.
Keeping the tyres flatter on the contact patch.

These En Route tyres have a flatter contact patch and I run around 5 degrees rear camber that negates to around 3 degrees under compression.

I try to keep around 5mm ride height to allow the chassis to pitch and roll for smoother weight transfer on carpet and more traction under accelleration.

Here is the body for my Rear Wheel Drive project. 

Clearance is NOT an issue.

I think I have around 1mm clearance without any scrubbing.

Front width is around 205mm. but camber adds more or less as stance is selected.

I've mounted the FD further forward on the chassis by 3mm then covered this by positioning the fenders rearward. This helps the diffuser line up 

The wheels are effectively only at maximum angle for short periods of time. But you can certainly notice when they are.

 You can get some serious angle.

But normal corners still look the same.

 Thanks for reading.


ps. Small upgrade... front turnbuckle.

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