Sunday, August 5, 2018

RC Drift Bible - RC Driving Skills - throttle



How good is your trigger finger?


While the above image is full brake, This image is probably 1/2 to full power. 


And this image is a very slight throttle or more likely due to position a slight off throttle with a slowing rear wheel speed.I use a 10% drag brake only.

Everyone that drives my cars, finds them "difficult" because everything is setup very "light to touch" and they give limited feedback.

Why do I set them up like this?

The main reason is that I can increase my finger accuracy by not fighting against hard trigger and steering spring tensions.
This also prevents finger tiredness
Response is also increased.



This additional image is also great for showing wheel and car speed.

Why? because the wheels are visibly rotating at the same road speed as I accelerate. Grip is present and no wheel spin which is essential for building speed.

In a real car cruising at 1500prm in 3rd gear at 50kph you wont break traction, even if you floor it.
In RC, we have 1 gear and soooooo much power available.

Replicating the reality is ultimately divisive for those who with to unleash the full potential of the RC non-realistic power.

For scale without a six speed gearbox we are going to struggle. But replicating car speed is we are targetting.

With limited grip, your finger is directly responsible for car performance.


There is theory but it's for the geeks related to grip vs wheel speed and car speed.

Basically I want to illustrate that as car speed comes up to max speed, the wheel speed won't be able to overcome it. Also too much throttle at any lower speed may result in a spin. 

so I want to give myself every chance I can to get to have control over what's happening in the drift zone while I'm there.
Especially on low grip surface with over powered machine.

On a high grip surface with sticky tyres, speed will be high and the only way to drift will be at 100% throttle most of the time.

As grip levels come down with harder tyres or slippery surface, throttle manipulation will be the key.

Once trained, your finger can override a lot of chassis imbalance and simply drive around issues.

before you blame the car setting. Think about your finger.

Am I using full power mid corner?
Am I even braking at all?

these are two indicators that your finger needs work.

At all levels of motorsport. modulating throttle and brake are equally as important as car setup.  Brakes can always lock, but good drivers don't lock the brakes.

Good drivers are more evident in the wet with smooth throttle application a key factor.


Even though I loosen the tension here, for beginners without accuracy yet... Increase the tension to prevent quick changes to max power. Forcing a harder accelerator can reduce the tendency to apply too much throttle from a stop or during mid corner.


This combo will go from from zero to max wheel speed very very quickly = less control


this combo will give more control. If track size can support it. I go for the highest possible ratio here.


and use all the car configuration starting with motor choice.


To support my finger use


For fine tuning, I use the EPA. or the ESC Max FWD Speed to the track surface on the day.
But if you find yourself reducing this too far... probably gearing or motor change is a better choice. 


This is one contentious part. I like to think that a linear relationship between you finger and the motor RPM is best. I like to know what to expect.

If you are not good at regulating your throttle % with your finger. Then setting an exponential or point curve to dull the response is ok. For RWD we want the smoothest response however 4WD may need a different approach to break traction on demand. 

However, learning to program a throttle curve, is just another parameter for advanced users, but in fact it's probably the beginners that need it most. Add this to hard to predict boost curve on the esc + feel + punch and other settings and you can get to a position where it's impossible to predict your throttle.

Setting everything to MAX is probably not the best option.

For me. NO BOOST, NO CURVE and I run a high RPM motor with least resistance. So response is fast and maximized to match my finger. Therefore it becomes light and hard for many to read.   

I can create my own punch and boost by using my finger. but I admit the spread of a high RPM motor can pose it's own issues.

So what is the defacto standard these days...?  

10.5T motor + TURBO. 

Why is this a good idea?

Well, you can use 1% to 99% with a broad spread of usable linear power. Then when you need between 100% and 150% you just keep holding the throttle as Turbo function is only possible at max finger squeeze.

This dual personality is widely used in drift world wide.  


But remember you finger also controls the brake in the same way, speed to adjust these little beasts in a train requires lightening reflexes, throttle position, 1/2 brake, full brake and back to the same throttle position in an instant.

All I can recommend is... until you can get control over your finger position.

you'll need to practice your squeeze level and count.

Divide your trigger into 10 sections.

one, two, three, four, five, six, seven, eight, nine, ten

three, brake, three   six, off, six

eight, two, five, six,  seven, off, three, full brake.

then try and use different positions on track.

see what changes when you can drift on 30% throttle.









Additional notes  from comments and questions... ESC programming
and Motor selection than your finger position. but it's all related.

Fixed  "Blinky". Timing.
Adjust the motor End bell position for fixed timing advance or retardation over the whole motor operation.
      Low -reduces RPM and gains torque
      Neutral - Manufacturer's set timing for measurement
      High - increases RPM and reduces torque.

Boost. Electronic RPM based advanced timing.
       Instead of winding the endbell of the motor, new esc can advance the timing at set RPM points.
       unlike the controller Channel Curve that changes the trigger position in relation to throttle %
       this applies power increases to the motor from certain start RPM ranges.
       so you can build an exponential gain into the motor rev range.
       like a supercharger or turbochager
      
Turbo. Electronic Delay advanced timing.
       Instead of winding the endbell of the motor, new esc can advance the timing after Full throttle or after set RPM
       typically on full throttle. a 0.2second delay might allow 10%~50% increase in RPM.
       you may hear these settings audibly as a high pitch whine as the motor may be pushed outside it's designed max RPM.
       usually reserved for a long straight.
       the turbo name was probably chosen because it's probably related to a slight lag.

Blinky advance + Boost + Turbo can result in a huge current draw and excessive heat and kill an ESC.
they can result in massive changes to the smoothness and responsiveness of a motor. 
Most ESC don't recommend boost + turbo over a 10.5T

So read your manufacturer settings. 

so there will always be a difference between people who like the linear curve and those that like a powerband or a high end spike.
it's up to you. but the input is always your finger. knowing where to accurately place your finger will determine the amount of control you have.

try all your settings... but don't neglect your finger excercises.



3 comments:

  1. A nice article Russell. hopefully its taken on board and understood!

    ReplyDelete
    Replies
    1. Question and discuss. Anything is a preference

      Delete
  2. Any chance getting a copy of the spreadsheet?

    ReplyDelete

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