Friday, August 2, 2013

Tandem Run: 2wd vs 4wd Eagle Racing R31 vs Yokomo DRB

This video shows I may need more experimenting on the RWD. It's still very smooth to drive and hardly ever spins out anymore but then still issues with angle and speed.

Any ideas would be appreciated. Thanks!

Wednesday, July 24, 2013

More Steering Pics

Top view showing the full steering design at neutral. Works very well. Has a very neutral handling in terms of the drift line it takes. Also, it is versitile in choosing a line but not as agile as a steering with more ackerman.

When more RWD comes out then I'll see which steering is more competitive. For now they do great with CS chases with a lot of drift angle and steering angle.

Front View

On this pic, we can see the ackerman screw adjuster. Great great mod I've done for myself. Seriously fine adjustable caster to help fine tune geometry.

Thursday, July 18, 2013

A solo run of the 2nd track session I took last week. It's the latest I have since I was unable to take a good video of yesterday's 3rd track session because I was overwhelmed with joy that my RWD kit hardly spinout anymore.

I could do more laps on the average without mistakes comparing it to most drifters that drift at our local track at R66.

I'll try to take tandem videos by next week.

Also, the parallel steering theory is indeed proven in my experience. It has more effective countersteering than my previous steering design. I feel like I want to try this without gyro too and just see it's improvements.

However, with the new setup, My kit is now rear heavy biased. I'll take pictures and video maybe of it while I scale it. ^_^

Tuesday, July 16, 2013

Since after running my kit after the first track day, I have realized that the earlier modded knuckle arm gave me a lot of negative ackerman or toe in gain as I increase my steering angle. It gave a nonlinear steering feel.

(Basically, I have experienced that more toe-in does give the car more rotation on off-throttle. Which isn't what I'm looking for when tuning a rear wheel drive that don't have front pull to give less rotation. Also, the steering response is lessened.)

Going back to nonlinear feel, the steering response would be from toe in gain to toe out gain normally with the old knuckles. So that would equate to non-linear assist as well from the gyro in my theory. Low response from zero angle to a certain steering angle, then toe out gain from that point to full lock.

With the MST XXX steering knuckles, I have successfully eliminated any toe in gain from my steering system. It goes from almost parallel from zero to a certain point before hitting full lock, to toe out gain to full lock for a good responsive switchback when you've put too much angle on the kit.


Notice that there is a KPI(king pin inclination) on the knuckle arms. Upper ball and lower ball don't have the same position as the other. The lower ball is connected nearer the tires and the upper ball connected nearer to the chassis.

That in itself creates positive camber gain as you increase steering lock. Does have the same look as having a monster caster of more than 15deg. I don't have actual measurement though. Hehe!

Monday, July 15, 2013

Eagle Racing R31 RWD Track Day 1

Day 1 wasn't too bad. But when I first drove it for a few minutes, I found that the R2 threaded tires was too slow for the track size and that driving figure 8's and even doing shallow long drift at home wasn't anywhere near for what a full size track had required of driving skill and kit tune for RWD drifts.

First 30mins(about) was the worst experience for me.

I couldn't do pics and videos as my concentration was needed with setting up and properly driving the RWD kit. I did however get videos thanks to friends, Jon Castro and Thirdie Lopez.

I did manage to get the kit going and soon was driving at ease just like any CS kits that were present. Maybe even had better control than the average drifter. Found myself switching tires to an HPI Type D on all 4 wheels since it was the next grippier tires I had with me.

- Type D pics -

Tandem between R66 Track Owner: Dennis Tan and my 2wd drift car. This was within less than 1hour of run on track with the RWD kit.

I realized after the track session that I'm running on the wrong front springs. It made driving a little harder because having harder springs at the front did react a little to fast even for the gyro. Resulted in a lot of spin-out since my hands aren't really used to driving RWD just yet.

Tuesday, July 2, 2013

Eagle R31 CF Conversion Custom RWD

This is my second chassis that I have customed for RWD drifting. I'll be talking purely on setup so that I can help many RC drifters that want to do RWD RC drifting.

Main chassis pic. This is a pic I took of the chassis before i placed a gyro. Battery CF plate is uninstalled at
this time.

Front end pic without the weight placed. The caster is fully fine adjustable. Got this control arm modification idea from a Brunei drifter I think. I forgot his handle at RCDRIFTREVOLUTION. It's a great mod since I can adjust caster independently from camber as compared with having 2 turnbuckle links.

The adjuster is a servo post from a TT01. There's hardly any slack on the front suspension as compared to the stock one with c-hubs.

The thing that holds the screw for the control arm is a cut TA03F/R suspension block/gearbox. Yep, got a lot of those. Not to worry. Not really much I can do with a TA03 lately since I doubt there'd be anything better than RWD RC drift. My TA03F/R has always been my guinea pig chassis for everything I try new. Countersteer back in 2010, and RWD development back in 2011. All of which were successful but not really tuned to it's pinnacle or track worthy/competition setup.

Anyway, It can be replaced with reholed R31 suspension blocks to do away with cannibalizing a TA03 gearbox. Hehehe!

Spur gear is a Tamiya 102T 0.4module and a 50T 0.4 module Tamiya pinion gear. Front center pulley is an 18T Eagle racing aluminum pulley, Rear center pulley is an R2 18T aluminum also.

Rear pulley meanwhile is another 18T aluminum (HPI) and rear differential pulley is 39T. All stock basically giving me an FDR of 4.42.

Replaced the rear suspension set with a front suspension set so that I get a fully adjustable rear toe. Right now I have about 4+ deg of toe in.

This is a close-up view of my new camber link which is connected to the suspension arms giving me lower roll center. It's screwed to where the droop screws were. Droop is set to no limit.

I first encountered this mod through a fellow drifter from Philippine R/C Drifters who now resides in Japan. Shout out to Joseph John. Lastly, I saw this same mod (almost) on one of Robekensugi's YouTube video on an Eagle Racing Front Motor conversion. A shout out to him as well. Thank you! ^_^

Rear end view were we can now see an HK401B gyroscope installed. I have a very good copy of it. It's modded with glue-stick all over it's inside just as the one I saw on YouTube. After trying this very good copy of gyro, I suddenly feel like setting up and flying a Heli. Hahaha! Hmm, seriously though.

Battery I use is a Tiger equivalent re-branded 3300mah 25c. Reason I got this battery is because it's locally available here in the Philippines and it's light weight compared to all the others i weighed. This one weighs at 199g.

Another shot of the rear showing the weight I placed at the rear diffuser. It's 38grams in weight to get it at 50/50 weight distribution approximately.

In my opinion and theory, front momentum is important. Given that, Momentum = speed X weight. I believe that front weight should be more or somewhat equal to the rear weight for better control and stability.

Given a kit that is running at an angle, speed of front and rear is about the same. Or depending on control input, rear can be faster. Which means if you have a heavier rear, momentum of rear is more than what a front momentum has. That can be a result of a spin out in general.

Of course, it can be countered with good steering setup and suspension tuning. But that's its natural tendency given my theory.

Here's a shot of the new placement of the steering wiper arms. If you check the pic, there's a hole at the front of the wiper arm. That's were it was originally placed at. Also, the steering bridge is now replaced with a turnbuckle. Adding too that a link was used to get the ball position at the wiper arms more inside to get more stability by reducing toe gains.

This modification, along with the caster adjustability, seriously gets pure control of ackerman.I believe the stock R31 suffered from a lot of negative ackerman or toe-in gain which is OK for low overdriving CS setups but not really for RWD setups. This is a highly recommended modification for any R31 kit for the highest stability.

Front End showing the front weight installed. Weight is 120g. This is still in it's development stage so please forgive the chassis appearance. It's still in the works. Hahaha!

Here's a pic where we can see a fair detail of the screw end I was talking about holding the control arms. This is how I control Caster. Tightening = less caster and Vice-Versa.

This is a modified TA05 V2 steering knuckles. I used a plastic plate to get a KPI on the upper joint. Then I moved the lower ball end towards the wheels more.

Ball and adjuster I used on the lower end is from a Tamiya CR-01 crawler and a TRF414M adjuster. That gives me a more robust and less slack on the joint comparing it to a setup with Chubs.

And finally, pic of my chassis in it's current state. 

And the Test run at home. So stable. Also, I feel I can get more speed now thanks to the gyro. I have no video of it running without gyro but it was very unsmooth to drive. I also tested at the track but I could only clear 2 corners at best. Hopefully this coming Wednesday, I'd get more pics and videos.

Hope this helps out drifters that want to RWD modify there R31's. Leave any comments or question if any. Thanks!