Hello to all,

just wondering if anyone using the brake function of its ESC to help in downline braking. I could imagine that this makes a lot of sense, although it should be used carefully.
If yes, what settings and idle RPM should be adopted? I have the Plettenberg / Schulze 32.55k setup.

Regards,
-Fabrizio

How should that be used?
I've softbrake in my ESC configuratio.
But that will stop the prop when landing? How do you sugest to use that function during the flight.
I've an Impact and if i could brake a litle bit the downlines, that would be great.

Regards
DV

I've read somewhere on these forums that an idling large diameter prop presents much more of a braking effect than a stopped prop. It seems to make sense if you think about it. Besides, having a brake engage to quickly stop a large diameter prop would seem to be putting a lot of inertial stresses on the motor shaft and/or gearbox.

Maybe someone else can corroborate that.

Rick

Hi DV,

I think that the brake works best by braking the propeller turning at a low RPM, not braking it completely. As Electrick wrote, a turning prop brakes much better than a stopped one. I will test this the upcoming week. Any more inputs?

-Fabrizio

Hi

I've tested today the downlines with softbrake and without it, but haven't seen no diference in the speed.

I've softbake in my ESC. When i put the throtle in idle the prop keep turning, but the softbrake doesn't act, because the throtle cut is not activated.

In the downline, when i activate the throtle cut, the softbrake act, but the prop turn quarter turns , and stop, turn a bit more, and stop, etc, etc. Does not turn continuously. It seems the brake even "soft" is a little bit "hard". My ESC is the MASTER 77-OF ( Hacker C50-14XL, APC-E 22x12", Impact)

Regards

DV

I believe the new Hacer 90A regulator has what they call "F3A Brake".
I would guess that this function allows the propellor to rotate, but not to "freewheel" quite as fast as it does without any brake on. On my current 90A Hacker regulator, the motor is rotating (windmilling) quite fast on downlines. Maybe the new functionality will make it act more like a 4-stroke, rather than a 2-stroke???
Magne

The "brake" function in an ESC is to brake the motor,..i.e. stop the prop. A windmilling prop (no power from motor and no brake) is the highest amount of drag you will find. Using the ESC brake function to stop or slow the prop will decrease drag substantially.

It's very easy to see the drag relationship between a stopped, windmilling, or folded prop if you fly a hotliner a bit. A "true" hotliner,.. with appropriate power, will climb vertically in the 70 to 120 mph range (depends on how much power you shove in the nose ), then with the prop stopped and folded, can get into the 150 to 200 range after a short dive power off. However, if the brake gets disabled on the ESC so the prop doesn't stop and fold,.. and it's left windmilling, it's like flying with a boat anchor attached,.. 20 to 30 degrees nose-down just to keep from stalling. It's VERY OBVIOUS the drag produced from the windmilling prop. On certain funfly planes, i've bolted on folding props just for things like climb and glide, so the prop will stop and fold. That's made the difference in a 2 minute glide after a 20 second climb,.. up to a 7 minute glide after the same climb. The point is,.. if you want aerodynamic braking, you want the prop windmilling freely, not stopped or slowed.

There is a natural method of seed dispersal in which Mother Nature takes full advantage of the high drag induced by free windmilling effect of a prop blade. Up here in the NorthEast, it's just about time for the trees displaying this mode of seed dispersal to strut their stuff. We don't need to complicate something this simple, perfected by Mother Nature herself, eons ago.

MattK

Hello.
Could someone please explain the following:
1. What is the functionality of the F3A brake function in the new Hacker regulators?
2. Why are 4-stroke engines said to give better downline breaking than 2-stroke engines?
Thanks.
Magne

Larger diameter prop?

Steve

Electric motors typically use larger props.
However, 140-160 2-stroke and 4-stroke engines use very similar props. (typically 16x12 to 18x10 or thereabout. If anything, the 2-strokes use larger props than 4-strokes.)
Surely it must be because the 2-strokes will wind up more than 4-strokes do (this can easily be heard when flying) which means that providing some degree of breaking (i.e. reducing the free wheeling speed of the propeller) must help slow down the model.
Magne

As far as I have read, the F3A brake on the modern controllers will allow the prop the turn, but not to windmill, what will hapen is that the prop starts ackting as a huge plate, slowing down the plane a lot. I understood that with the newer hacker controlers you can actually control the bracking with your throttle stick.

This is also what happens on a fourstroke, the windmilling of a fourstroke is much less then with a 2-stroke.

Winfried

Is it correct to say the only way to activate the break is to shutoff the motor? So do people using brake typicallly take-off and fly complete pattern with no idle? Or shut it down for certain manouvers? Or does the break work while the motor is idliing?

The point is that while a windmilling prop does cause more drag than a static one the energy in the "falling" model is driving the prop and accelerating it to the point where it doesn't produce as much drag as it would at lower rpms.

My understanding of the new Hacker F3A and Shulze Future "KA" controllers is that they are modified versions of car controllers where the "off" point of the controller is nominally at half stick and that moving the stick from half to low gives proportional dynamic braking. Of course at some point during this movement the dynamic braking will be enough to actually stop the prop from turning and so reduce the drag.

The way these controllers are designed to be set up is that the low end point is adjusted to give enough braking to slow the prop and give good drag but not enough to stop it. The easiest way to do this is by using the throttle trim lever. Also most people will program a throttle curve so that the "off" point is moved way below centre to a click or two above bottom stick. This way the prop will start virtually as normal with all the braking on the last click or two. You cannot set up a controller with "normal" braking to do this as the braking levels are pre-determined and are too severe for the effect we want.

The Shulze controller uses fixed pulse widths to determine the full throttle, off and full brake postitions. i.e. auto detect is disabled. I don't know about the Hacker one.

The disadvantage of this system may be when executing stall turns etc. when a little airflow over the rudder is useful. It remains to be seen whether I can remember to keep a few clicks on in the heat of a comp, flight!

Malcolm

If you want to try a good braking esc, give the castle 85hv a try. It doesn't cost mega dollars either. Last year I would always set an idle speed prior to takeoff. Lately I no longer do it and have found I don't notice any difference in the air except in the spin. With the castle, the brake engages when the stick is pulled back to idle within the last couple clicks of the throttle stick. You program the amount of brake you want to be applied basically by flying and adjusting until you get it to the point where you like it. With my hacker I'm at 7% right now. I can fly the longest downlines at a consistent speed and the prop never stops, you can hear it working. On the 45 down with the snap and a half it will get a little slow after the snap, so I just add a click or two of throttle to disengage the brake. The spin you can go into it with a slight bit of throttle and when your ready to enter the spin, I'll throttle all the way down, the brake engages, and it seems to give a lot cleaner break at the stall then I use to get without it. So I feel it helps there also. I think everyone will be using these type speed controls once they see them in action.

Stick with the version 1.23 software on the castle, the new 1.5 has a problem when it comes to the use of the brake. Somethings changed in the programming, I thought it was gonna tear the motor out of my plane, but the 1.23 works great. The 1.5 more for helis anyway, they're supposed to be looking into it.

rm, you are saying that on/off brake is better than proportional brake? Four years ago I switched from 2stroke to 4stroke to go from on/off throttle to proportional throttle. I didn't agree with you then, and I don't agree with you now.

Adam Glatt
Team Schulze
flying the Schulze 32.80ka, and loving proportional brake.

I don't care if you agree with me or not and since I've never discussed 2/4 stroke with you have no idea what the hell your talking about.


Now I see, Castle shut your sale down.

The Castle brake is not really as simple as on/off. The Castle brake is basically setup (using ATV/endpoints) to engage on the bottom click of throttle, and then the amount of the braking force is variable depending on the RPM of the motor and the airspeed of the plane. At higher speeds the brake will engage more aggressively, and then taper off as the RPM and airspeed decay. In practice, I have found this to be very useful, as the same brake setting that works for downlines also works for 45 downlines and the backside of looping maneuvers.

The Castle software has several parameters that can be tailored to adjust how the brake reacts, and the overall strength can be adjusted to essentially set the airspeed when the brake is engaged. In practice, the brake strength is pretty equal to downline airspeed, and you don't need to vary the throttle stick in different (descending) flight attitudes to maintain the same airspeed.

The Schulze allows variable brake from the TX, but it seems you also need to use a different settings (on the throttle stick) to achieve the same airspeed on downlines, 45 downlines, and backsides of looping maneuvers.

Regards,

Dave Lockhart
Team JR
Team Castle Creations

From my micrologger graphs it can be clearly viewed that the brake power of the controller increases with downline length, ie: less increase in speed on downline (like a 45) less power used by the brake, and vice-versa. I suspect that if someone ever actually logs a Castle controller the brake is identical to what the Schulze is....I dont think there is anything ingenious about how these things are built.

I dont find that I ever change brake settings much at all during flight, but the option is there if you want. Plus I dont need a laptop at the field to set my controller

I have the Jeti 90 and have tried with and without the brake, the brake does work but I'm not sure how, I don't have a datalogger but do find that if idle is to low it seems not to slow down as well as with it a little higher, it's not an adjustable brake just on and off. There could be more advantages to the adjustable I'm sure but at least it does help with just on and off.
Steve Maxwell

I thought all the talk about electrics was how slow they fly and how to speed them up? Now all of a sudden some want slower flight? Or just downlines? Why? If I fly any slower on downlines, or anywhere, I'll go over the 10-minute time limit. I'm going 9:15-35 as is. There are only a handful of maneuvers that I want/use the brake on in my patterns. And it's not a spin or stall turn.

I haven't tried the proportional brake (CC or Schultz) so I have no feel for it, but the "off brake" in the Comp controller works well for me.

Steve, Unless you have the Comp 90, you want to leave the brake off cause it's not what you're looking for. Unless gearbox torture is fun .

Geee, glad to know I am not the only one

Agree with the brake, proportional is a great feature but very easy to overuse/misuse.

Hello Adam! just got a 32.80KA and have secveral questions. may i have your email to askyou a few precise questions?

thank you!!!

Marcelo

What about the folding prop planes that need the brake for longer thermal flights, also since my sailplanes have no wheels, it saves having broken props.I bought a Chinese Minimoa Glider and can find no info on it anywhere. Can anyone help on setting motor brake using transmitter i.e. full throttle on start up and setting according to beeps?
Thanks, Jim

As I was climbing up to 200 feet my o-ring broke and my prop came off.It was the 1st time my plane was ever able to glide in w/o power.Just like a dead-stick landing on a glow power plane.

If you can make your prop stop,your plane will glide further,but when it windmills it causes more drag than at a slow rpm.The prop is blowing air forwards,plus it blocking air.