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View Full Version : "F3A braking" on Phoenix ESC


Vitalka
10-28-2009, 08:01 PM
Hi,

I noticed that even latest firmware (2.18) still has no F3A braking function. Hacker/Jeti and Yge has it for sure. When CC is planning to add this very useful function?


"This is the addition of a proportional brake (now commonly called an F3A brake) to the controllers. Essentially it is identical to the brakes used on RC cars and works by initiating a brake at approximately 5% throttle and increasing braking power to 100% at 0% throttle position."

texasclouds
10-28-2009, 09:50 PM
Hi,

I noticed that even latest firmware (2.18) still has no F3A braking function. Hacker/Jeti and Yge has it for sure. When CC is planning to add this very useful function?





how is this useful? does it help slow the plane at landing?

Vitalka
10-28-2009, 11:08 PM
With most ESC (basicaly cheap) braking is only activated when moving throttle stick to 0%. F3A brake function allows to activate and adjust braking intensity at other throttle positions. It is useful for reducing model speed in downlines.

Larry3215
10-29-2009, 08:50 AM
How can the break be active at throttle positions above zero?

The esc would be telling the prop to go at the same times its applying the break? I dont see how thats going to work.

Castle esc's have fully programmable break strength and delay already and it works quite well for slowing down lines as is so I dont understand the need.

Vitalka
10-29-2009, 10:05 AM
Yes, Castle Esc has very flexible and adjustable braking settings. But braking does not work if you set idle rotating speed for a outrunner. I know it is hard to figure out how it works, but you can find proportional (F3A) brake description in most car ESC manuals, e.g.:

...
Emax car ESC instruction.
....

The ESC provides proportional brake function. The brake force is related to the position of the throttle stick. It refers to the maximum brake force when the throttle stick is pushed to the top point of the backward zone."
..

Larry3215
10-29-2009, 05:01 PM
I understand how it works on car controllers but car controllers work very differently from air controllers.

Also, I was under the impression that guys were setting their motors to idle at "off throttle" to eliminate or reduce the breaking effect or for scale operations.

Vitalka
10-29-2009, 08:53 PM
"24th F3A World Championships Technical Report

...

There is only one simple change worth mentioning surrounding the ESCís that was new. This is the addition of a proportional brake (now commonly called an F3A brake) to the controllers. Essentially it is identical to the brakes used on RC cars and works by initiating a brake at approximately 5% throttle and increasing braking power to 100% at 0% throttle position. This allows the pilot to control the downline speed with incredible precision. This is a big problem for electric motors as without the brake there is nothing to prevent wind milling on downlines. I managed to trade controllers with a friend and and have since tried out the downline break. It is a major improvement to the system and gives very good control of downline speed in all areas of the flight. It does take a bit of getting used to as it becomes important to now fly the throttle as idle as well which is something that most are not used to doing."

Larry3215
10-29-2009, 09:27 PM
Interesting. They must be doing some tricky programing so the break isnt active when the stick is moving UP or are they not starting the motor at all untill it reaches the +5% mark?

I can see how that might be usefull for the top 5% of pilots. Im no where near good enough to take advantage of that kind of controll :)

Octavius
10-29-2009, 09:45 PM
On cars it's spring loaded to return to the 5% (or whatever the driver set it to). So when you're parked the throttle is at 5% which is unlike how we're used to. Other than that it sounds exactly the same.

Larry3215
10-30-2009, 01:51 AM
It would be tricky to use no matter how they do it.

When I played with break settings on my 30% Yak I found that very small changes in breaking strength made all the difference between slowing your down lines and doing nothing at all. Too much break strength stopped the prop or nearly stopped the prop and that made for no slowing on the down lines.

Too little strength was just like wind milling and caused very little change in down line speed. If you got it just right it worked fairly well but it took a lot of fiddling and trial and error. I finally quit messing with it.

I cant imagine being fast enough on the sticks to play with it in real time but mostly I cant see being able to judge the effects on the fly. Downlines arent all THAT long and then your out of time :)

Vitalka
10-30-2009, 07:05 AM
Some modern F3A planes (e.g. Black Magic 3, Spark) has very stout and draggy fuses. Owners tells that in combination with correct prop braking they are so slow on downlines even requiring to add throttle.

Other area where prop braking is important is F3P (indoor pattern flying). A lot of pilots noticed that downline braking is more effective if motor tunned for some idle rotating. But as I sad the braking function in phoenix-10 ESC does not work in that case.