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ESC braking. Truth vs. perception. Please help!

Old 05-19-2010, 08:18 PM
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Default ESC braking. Truth vs. perception. Please help!

I just read through the [link=http://www.rcuniverse.com/forum/m_3236950/tm.htm]'05/'06 Braking Thread[/link], and feel that I am left with more questions than answers. Let me start with what I think I know:

1) A stopped prop has the least drag.
2) Electric motors do not create the same drag that glow motors do with a free spinning prop.
3) Properly used, braking does dramatically decrease down line speed if you want.
4) The majority of folks have little idea of how braking actually works on their esc.


which brings me to my initial set of questions:


1) What is "proportional" braking?
2) Would slowing down my down line in my square loop, stall turn, and outside loop improve my scores?
3) Where do Jason, Chad, and Dave use braking in their routines?
4) On my Jeti if I set an idle RPM at the lowest possible point before takeoff does the brake ever engage in flight?
5) How do you know at what point your particular esc is designed to turn on braking? Are they all set to zero throttle postion or is it a ms input issue?

OK. I'm sure I'll have plently more questions as the answers come in, but that's it for now . . . and of course thanks to all for taking the time to answer.




Joe
Old 05-19-2010, 09:03 PM
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Default RE: ESC braking. Truth vs. perception. Please help!

Joe, bottom line, in Intermediate you do not have any maneuvers with long vertical up and down lines. You don't need braking. Just keep the low idle setting. I don't use it in Masters. Never did and never will. You can't go by what the big guns in FAI say or do. They have some complex tall maneuvers that can lend themselves to a little braking. Just concentrate on perfecting the basic geometry at your level.

I stand corrected. I might use it occasionally on landing.
Old 05-19-2010, 09:26 PM
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Default RE: ESC braking. Truth vs. perception. Please help!

Joe,

For what you think you know....
1. A folded prop has the least drag.
2. Correct.
3. Correct. Dramatic is a relative term of course.
4. Also correct, in my experience.

Before answering the questions......your Emotion needs nothing to fly Intermediate....leave it alone. The need/benefit for braking (beyond an electric freewheeling) is dependant on many things....airframe drag, prop used, flying style, complexity of maneuvers, etc.

For your questions -
1. "Proportional" should mean the amount of braking is incremental based on the amount requested. RC cars have had this function for many years, and I believe some of the Schulze airplane ESCs have proportional braking (adapted from the car ESCs) that can be programmed so full idle is more braking than 1 click above idle, and 2 clicks above idle is the least amount of braking, and 3 clicks above idle would be the slowest possible idle (and I think the amount of range for the braking zone can be adjusted). I'm sure Chad will add to this if I don't have it right.
2. There is no criteria for speed in judging/scoring. However, there is the incredibly ambiguous "smoothness and gracefulness" criteria (which being so poorly defined I think should be eliminated from the judging criteria, but that is another topic). I would suggest that the best possible presentation would be one that is 100% constant speed. If the terminal velocity in a downline is faster than full throttle in level flight (let alone an upline), you will never be able to achieve constant speed.....ie, the "best" setups have slow downlines.....it is easy to speed up a downline (adding throttle)....it is not easy to fly the entire pattern at 100 mph, if that is what the terminal downline velocity is.
3. For me, I have a 3 position switch that is set for brake (normal flying), slowest possible idle (windy weather), and fast idle (stall turns and spins). I can always add throttle whenever I don't want the brake.
4. I don't think any of the ESCs will engage the brake if they are set for lowest possible idle (I know 100% the Castle will not).
5. I believe it is a particular ms.....that is certainly the case for Castle.

Regards,
Old 05-20-2010, 12:00 AM
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Default RE: ESC braking. Truth vs. perception. Please help!

Jeti doesn't brake unless idle is zero rpm on ground.

I'm still curious about the governor feature on some escs, whether they will contol rpm from over speeding in a downline. Off topic of course.

A peculiarity aboutnthe brake it will affect your line when it activates if set strong.
Old 05-20-2010, 03:18 AM
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Default RE: ESC braking. Truth vs. perception. Please help!



Try reading this http://www.modelbouwforum.nl/forums/f3a/78538-testverslag-axi-5325-24-a.html</p>

this guy is top 20 in the world</p>
Old 05-20-2010, 05:29 AM
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Default RE: ESC braking. Truth vs. perception. Please help!


ORIGINAL: Velco



Try reading this http://www.modelbouwforum.nl/forums/f3a/78538-testverslag-axi-5325-24-a.html</p>

this guy is top 20 in the world</p>

Thanks Velco,

Interesting test. Right up my alley, and shows that a smaller motor is every bit as powerful as its big brother plus also shows that the pros do in fact use braking.

Funny aside . . . interesting looking at written Dutch as you can see the mixing between English, German, Dutch, and French . . . just interesting I think
Old 05-20-2010, 05:32 AM
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Default RE: ESC braking. Truth vs. perception. Please help!


ORIGINAL: J Lachowski

Joe, bottom line, in Intermediate you do not have any maneuvers with long vertical up and down lines. You don't need braking. Just keep the low idle setting. I don't use it in Masters. Never did and never will. You can't go by what the big guns in FAI say or do. They have some complex tall maneuvers that can lend themselves to a little braking. Just concentrate on perfecting the basic geometry at your level.

I stand corrected. I might use it occasionally on landing.

Thanks Joe, Clearly your advice is right in line with that of Dave and Chris plus based on my performance last week; I need a lot more focus on simple items like centering my maneuvers, etc. before I worry about using brake. Having said that I will say that as always, I've got that "curiousity bug" that makes me want to understand my own equipment just for the sake of understanding


Joe
Old 05-20-2010, 05:40 AM
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ORIGINAL: DaveL322

Joe,

. . .

Before answering the questions......your Emotion needs nothing to fly Intermediate....leave it alone.

For your questions -
1. ''Proportional'' should mean the amount of braking is incremental based on the amount requested. . . . I believe some of the Schulze airplane ESCs have proportional braking (adapted from the car ESCs) that can be programmed so full idle is more braking than 1 click above idle, and 2 clicks above idle is the least amount of braking, and 3 clicks above idle would be the slowest possible idle


3. For me, I have a 3 position switch that is set for brake (normal flying), slowest possible idle (windy weather), and fast idle (stall turns and spins). I can always add throttle whenever I don't want the brake.



4. I don't think any of the ESCs will engage the brake if they are set for lowest possible idle (I know 100% the Castle will not).


Regards,


Dave,

a) I promise to leave my Emotion as is and continue to practice, practice, practice.

b) Aren't 1 and 4 above contradictory? If an esc has proportional brake then won't it brake even with a slight idle set, just not as hard?

c) On my 12X I am experimenting with using Prog Mix 3 to create a thrott - thrott mix allowing idle, low, high, but I can only get Pos 0 and Pos 1. Is there some trick to getting 3 positions to appear on the mix page?


Thanks again for sharing your experience!




Joe
Old 05-20-2010, 08:10 AM
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Default RE: ESC braking. Truth vs. perception. Please help!


ORIGINAL: 2Sunny


ORIGINAL: DaveL322

Joe,

. . .

Before answering the questions......your Emotion needs nothing to fly Intermediate....leave it alone.

For your questions -
1. ''Proportional'' should mean the amount of braking is incremental based on the amount requested. . . . I believe some of the Schulze airplane ESCs have proportional braking (adapted from the car ESCs) that can be programmed so full idle is more braking than 1 click above idle, and 2 clicks above idle is the least amount of braking, and 3 clicks above idle would be the slowest possible idle

3. For me, I have a 3 position switch that is set for brake (normal flying), slowest possible idle (windy weather), and fast idle (stall turns and spins). I can always add throttle whenever I don't want the brake.

4. I don't think any of the ESCs will engage the brake if they are set for lowest possible idle (I know 100% the Castle will not).

Regards,
Dave,

a) I promise to leave my Emotion as is and continue to practice, practice, practice.

b) Aren't 1 and 4 above contradictory? If an esc has proportional brake then won't it brake even with a slight idle set, just not as hard?

c) On my 12X I am experimenting with using Prog Mix 3 to create a thrott - thrott mix allowing idle, low, high, but I can only get Pos 0 and Pos 1. Is there some trick to getting 3 positions to appear on the mix page?

Thanks again for sharing your experience!

Joe
a) Perfect!

b) Nope. Brake is brake, idle is idle. If the brake engaged to keep the idle from spooling up, that would be governing....different function. The only ESC I know of that will use the brake to govern to a specific RPM is the Castle, when using it for F2B (Control Line Stunt), and then you lose the ability to throttle the motor....it will run at a fixed RPM (full throttle, which CL guys are primarily adjusting power output with the prop).

c) It is 3 position switch, but only 2 positions are engaging a mix. Pos 0 is "off", and the endpoints are adjusted to put the ESC in brake mode. Pos 1 effectively adds a bit of idle trim putting the ESC at low idle (minimum), and Pos 2 increases the mix percentage to put the ESC at fast idle. I can show you the setup on my 12X this weekend at Conyngham.

Regards,
Old 05-20-2010, 01:04 PM
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Default RE: ESC braking. Truth vs. perception. Please help!


ORIGINAL: DaveL322

b) Nope. Brake is brake, idle is idle. If the brake engaged to keep the idle from spooling up, that would be governing....different function. The only ESC I know of that will use the brake to govern to a specific RPM is the Castle, when using it for F2B (Control Line Stunt), and then you lose the ability to throttle the motor....it will run at a fixed RPM (full throttle, which CL guys are primarily adjusting power output with the prop).


Hi Dave,

Actually Schulze had that function in place for one of the Canadian pilots at the F3B worlds in 2006. We (Adam and I) spent a lot of time working with the pilot (Kim Doherty) and Pletty and Schulze to get a system to work for that application. A normal governor is not fine enough though, Schulze modified the normal governor to give a huge resolution over a very small range so they could adjust the motor rpm by like 10 or 20 revs at a time or something.



Old 05-20-2010, 07:50 PM
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ORIGINAL: DaveL322

. . . I can show you the setup on my 12X this weekend at Conyngham.

Regards,
Sadly I will be in Brussels this weekend, working, so the PA competition is out for me. Don't suppose you are considering coming down to the Bealton meet the following weekend?



and . . .

call me "thick", but I'm not understanding proportional braking. Idle = 100% brake; 1 click of throttle = 60% brake; 2 clicks of throttle = 30% brake, and 3 clicks = no brake BUT on the ground 3 clicks of throttle equals a spinning prop.


I'm certain some part of that is wrong, so where is my misunderstanding?



Joe
Old 05-20-2010, 07:51 PM
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Default RE: ESC braking. Truth vs. perception. Please help!


ORIGINAL: can773
Hi Dave,

Actually Schulze had that function in place for one of the Canadian pilots at the F3B worlds in 2006. We (Adam and I) spent a lot of time working with the pilot (Kim Doherty) and Pletty and Schulze to get a system to work for that application. A normal governor is not fine enough though, Schulze modified the normal governor to give a huge resolution over a very small range so they could adjust the motor rpm by like 10 or 20 revs at a time or something.




Chad,


Did anything commercial ever come of that application test?
Old 05-20-2010, 10:52 PM
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Default RE: ESC braking. Truth vs. perception. Please help!


ORIGINAL: 2Sunny

Chad,


Did anything commercial ever come of that application test?
As far as I recall its just software, so it was applied to an off the shelf esc at the time.
Old 06-04-2010, 02:30 PM
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Default RE: ESC braking. Truth vs. perception. Please help!

Joe,
On my 12X, I use the throttle hold function as a "engine start" set to the upper right-hand switch and then set my low idle to where I want on the throttle curve screen. I set the idle to get the most drag from windmilling. So on a down line at zero throttle, I don't get any acceleration.

I also like using the throttle hold as a safety function in case I bump the throttle joystick. I think of it as an "ignition on" switch.

BTW I loved your flying and your plane this year!
Old 09-19-2011, 07:29 AM
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Default RE: ESC braking. Truth vs. perception. Please help!

Hi guys,

  I am having issues understanding how to truly "set up" braking on my Castle 85HV.  I have set the braking to 50% on the ESC.  When the plane is sitting on the rwy ready for takeoff, the one click needed to start the prop spinning seems a little high but if I use one less click the motor stops spinning.  In the down line, I can literally hear the prop picking up considerable speed and then when I pull level, I can hear the prop decelerating.  This, of course, is at "idle" or with my stick pulled all the way back.  I have no switches programmed at this point to set different braking.

My down lines are just too fast and I should be able to have more of a constant speed flight than what I am experiencing.  Can someone help me understand how I need to actually accomplish using the braking system?  Here is my setup:

De Ja Vu
Neu 1513/2Y motor
Castle 85HV (because my ICE 80 is in recall)
Falcon 21x14 prop
10S batteries
Futaba 10C radio

The plane was more constant speed with the ICE 80 and an APC 20.5x14.  The only thing I can think of is that the Falcon is half the weight of the APC but I would think that would make it easier for the motor to brake vs. a heavier prop so that's probably not it at all.  I really just need help in setting this up whether it be in the ESC or the radio itself.

Many thanks,
Scott
Old 09-19-2011, 08:07 AM
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Default RE: ESC braking. Truth vs. perception. Please help!

Scott
The most brake I can get on the non Contr De Ja Vu is 30% and even then I have to be gentle in throttle up after a down line brake event. [ I use no brake on Contr Drive De Ja VU] I suggest you put your throttle trim on the left slider and change your "step number to a lower number. Also you want approx. 30% travel. I use this as double arming mech. as I always turn everything on with the slider in the full up position so no matter where the throttle stick is put it will not arm the speed controller untill you pull the slider all the way down! [Last thing I do before taxing out!] Make sure the slider is down and no prop rotation at idle in order to have the brake engaged. If you have a maneuver where you don't want brake one ratchet click up on throttle stick will give you a rotating prop idle. Check this on the ground and adjust throttle AFR if necessary.
Dick
Old 09-19-2011, 10:12 AM
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Default RE: ESC braking. Truth vs. perception. Please help!

Hi Scott,

Couple of things: one of my mentors suggested that anything below 80% brake on the 85HV doesn't do much. If you have your brake on and prop is accelerating, the brake strength is too low. I had/have about 96% brake on my ICE HV80 and it keeps prop from revving in down lines, stops prop on landing.

For motor spinning/stopping, it takes more energy to start a motor spinning (overcome resistance/friction, etc) and thus motor start throttle is higher than motor stop throttle position (just learned this myself not long ago).

I have started flying with a 'flight idle' and have my brake on a switch, similar to post above. If you use your trim to set up an idel rpm, the motor will essentially work as a brake to keep this rpm in down lines; it will not let the prop spool up.

So, either try increasing the brake, or actually keeping a few clicks of throttle on.

As the original post says, there are a lot of thoughts/opinions/etc on what is the best braking method. For me, the brake seemed to work OK, but throttle on after braking was not a smooth transition, sometimes made noise, and going from stopped prop/no wind to moving prop is a significant transient.

With a nice size prop and low idle rpm, my plane still slows down nicely, does not accelerate in down lines, and really is a lot smoother through looping maneuvers.
Old 09-19-2011, 11:36 AM
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Default RE: ESC braking. Truth vs. perception. Please help!

Joe
Evidently the "Bracking software is different on the HV85. I have not used used that one only the ICE HV80. So my comments relate to the ICE unit only. Glad to know they are different as I have a HV85 being delivered today as a result of the Castle ICE HV80 recall.
I found that the prop selection had a big effect on how much and what type of braking works best for a given aircraft.
Dick
Old 09-19-2011, 12:23 PM
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Default RE: ESC braking. Truth vs. perception. Please help!

I don't know if there is any difference, just know the guy who told me that (need high brake setting) was using the HV85. My experience is with ICE HV80.
Old 10-23-2011, 07:08 PM
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Default RE: ESC braking. Truth vs. perception. Please help!

2Sunny,
What braking did you end up using on your pattern planes? I know you run Pletis, and am looking to use the same motor on a HV80. I sent you a PM about the motor.
Old 10-25-2011, 01:42 AM
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Default RE: ESC braking. Truth vs. perception. Please help!

i have been flighting for 2 years with my integral using the following settings in the ESC (spin 99, motor Axi 5325).
I realized that brake runs when there is in idle status (0 rpm). Initial brake starts braking motor to desired % and for an smooth braking a second brake takes the control after few miliseconds.
In my opinion: excesive brake set up in negative, when you try to do a flight with homogeneous speed. Your flight style determines your esc settings. American flight style is faster than european, so downlines cant be slower than the rest of condition flight... is just an example.
try flight with the setup i attach

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Old 10-25-2011, 06:22 AM
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Default RE: ESC braking. Truth vs. perception. Please help!

Just a couple points RE Castle ESCs and braking -

There are substantial differences in the braking software in different software versions, as well as the startup, and restart (after brake was engaged, but prop is still spinning) behavior. The braking percentage effectiveness changed substantially on some software versions; the older software (~1.56, used on the HV85 before the HV80 existed) produced much greater braking at low percentages of brake strength, and then the braking strength was reduced at some point with the 2.xx software (still be before the HV80). Comparing old software on the HV85 to new software on the HV80 is comparing apples to oranges (mostly because of the software).

Because there are hardware differences between the HV80 and HV85, there is also some very slight differences in the software, however, with equal settings, the end performance should be the same (and appears to be the same when I've run both ESCs on the same motor).

At this point in time, for pattern, I see no benefit to running older versions of the software. Run the latest stuff....3.2x and you should have the smoothest initial starts, highest power, and least chance of screeching (loss of timing) at full power.

The maximum brake % I recommend (for pattern) is 30% as at this brake % I have not seen any problems with hard restarts in the air - I stick to 30% with the HV80 and HV85 and all motors - Neu, Hacker, Pletty, inrunner, inrunner geared, outrunner. SOME combinations of motor/props/planes will happily run at a higher brake % without having hard restarts....but that is a minority of combinations.

Regards,
Old 11-14-2011, 06:38 AM
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Default RE: ESC braking. Truth vs. perception. Please help!

Thx Dave!

I wasn't aware of that. I will have to update my ice 80's to the new software..

C

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