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F3A Braking

Started by DaveEast, 15, December 2010, 03:22:10 PM

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DaveEast

Just been watching Andrew Jesky talking about pattern flying and he mentions setting ESC braking, he was using a Castle Creations Phoenix Ice Lite 75 for this particular practice plane, how do you set it and which controllers do this??

Cheers Dave

Alan Wild

All the commonly-used ESCs for 2M F3A electric models offer braking.
I don't know anything about the braking with the YGE ESCs, but have used the older CC one (?85 HV was it called?), and the jeti 99 spin opto(which I believe is identical to the Hacker equivalent).
Both the CC and the jeti have several programmable features(percentage of braking, delay before coming on,interval between commence and final  brake effort, &c) and they share the need for the motor to be at effectively the lowest point on the Tx throttle setting, before the brake comes on.
I have no practical experience with the other (Schultze) ESC, but I think the brake can commence higher up the throttle setting on that one?
I think it's fair to say that the CC ESCs have had a few issues with the built-in programs (?firmware is it called?) for their braking.
Certainly I had a few weird "Switch-on shrieks" with the brake on an early firmware version that I tried, and a few instances of "loss of synch" with rapid throttling-up with some of the newer more powerful motor batteries----none of which has happened with the jeti.
Ironically, as the ESC braking has become more sophisticated, I think the need for it has dropped away to a large extent---a lot of the current 2M leccy models are quite draggy,relatively lightly loaded, and with the props in the 21" dia region(and the power available from the motors/batts), the downlines can be made slow enough without an ESC brake.

DaveEast

Alan
Cheers for the info, I did look at the CC website but it was not very clear.

Dave

Alan Wild

QuoteI did look at the CC website but it was not very clear.
Yep, I think it's clearer, if you actually possess a CC ESC, and their Castle Link PC gadget thingy----then you download their instructions and do all the programming from a simple screen on your pc---or at least that's how I think I remember doing it!
The jeti ESCs have a jeti-box thingy,which lets you do all the programming on the bench,or at the field, quite easily---I believe the latest CC models may have something along the same lines??

Richard Christopher

Schulze 32-80KA is the ESC I have used on Plettenberg and Hacker motors for 2m electric. The "K" in the model reference is important - it indicates that it has a brake programme specifically for F3A.

This ESC has no programming on the unit itself - instead it has a series of small switches which are set to "on" or "off" to provide different timing, braking etc. Once you select the F3A brake (switch 1 to "on" from memory), the brake setting is then programmed on your transmitter.

Throttle travel (ATV) at 0 = no motor power and no brake, positive ATV = motor power, negative ATV = braking effect. Example: if you set the 0 point at mid stick, anything mid stick forwards progressively increases motor rpm and anything mid stick backwards progressively increases the braking effect.

By programming a throttle curve you can decide which position of the throttle stick = 0..... above the 0 point is throttle increase, below 0 point is brake increase. I have my 0 point set at about 3 clicks up from idle, as I only find it necessary to use brake on very long vertical downlines (e.g. Fig 6 in the F11 schedule). In fact I have this throttle curve set-up as a flight condition and only switch it in for the Fig 6. I find a steady slow idle (about 800rpm) provides adequate braking effect for all the other manouevres.

I found that full throttle occurs at +120% ATV and optimum braking effect is around -80% ATV. I started at -90% and found the model was too slow on 45 deg downlines. I like the ability to adjust the brake by simply playing with the "low end" of the throttle curve(s).

The brake is also very useful for landing.


DaveEast

Richard thanks for the information, do you set your throttle atv to max, on my DSX9 that would be 150% ?

Cheers Dave

Richard Christopher

Hi Dave,

It was a while ago since I set mine up but I'm pretty sure I started at 100% ATV then ran the motor with stick fully forward and increased ATV until there was no rpm increase (a bit like leaning out an i/c engine...those were the days!).

If you set throttle to max ATV from the word go you might find the last part of throttle stick travel has a dead spot (i.e. full rpm will be reached a few clicks back from full stick movement). Hope this makes sense?

Regards,
Richard.

DaveEast

Richard
I do understand and will double check my atv's. I am a little confused about the throttle curve, are you trying to get an idle before pulling back to brake?

Cheers Dave

Richard Christopher

Hi Dave. See my PM in your inbox.

DaveEast

Richard
Thanks for your time, and on your advice I need somebody using an idle setting on a JR (DSX9) to explain how to set it?

Cheers Dave

Alan Wild

FWIW, Dave, I use two throttle curves on the dsx9. I leave the digital throttle trim at 0.
Curve  1 starts at 0, and the low-position travel adjust is set to match the lowest timing available on my (jeti 99 opto) esc.
Provided you switch the power to the esc at start-up, with the TX set to this position(curve1,trim at 0, stick at the bottom),this will arm the esc, and operate whatever braking you have programmed into the esc.
Curve 0 is just the same as curve 1, EXCEPT that it starts a few points above zero(in my case 8.5 from memory)---whatever is just high enough in practice, to keep the prop turning, when you take the throttle stick fully back. NB if you switch from curve 1 to curve 0 after arming, the prop will not run---you have to give the stick a little "bump",presumably to overcome a little resistance from the magnetic forces in the motor.
You have plenty of options as to how to select the two curves----personally I use the T HOLD/MIX switch at the top left back  of the TX case.

DaveEast

#11
Thanks Alan, that's works really well though I may have my 1 and 0 the other way round, thanks again.