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Old Nov 26, 2003, 07:37 PM
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Rackey's Avatar
Savannah, Ga
Joined Apr 2002
130 Posts
Why turn off or leave on the esc brake?

I see that there is an option to disable the brake on a lot of ESCs. What are the reasons that you would want to turn it off or leave it on.
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Old Nov 26, 2003, 07:59 PM
Mitch G's Avatar
Naperville, IL USA
Joined Nov 2000
1,886 Posts
When flying a plane with a folding prop, it's helpful (necessary) to enable the brake so that the prop will stop spinning and thus fold back.


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Old Nov 26, 2003, 07:59 PM
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slammin's Avatar
Everett Snohomish, Washington, United States
Joined Jun 2002
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for anything with a folding prop, the brake is almost a must. If the prop doesn't stop, it won't fold. On my parkflyer planes I usually diable the brake - it's not powerfull enough to stop the prop when I cut the power, but it will keep drawing amperage and trying...

Chris
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Old Nov 26, 2003, 08:10 PM
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Bill Mixon's Avatar
Georgia
Joined Mar 2002
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You would want to leave it on when you need a prop to stop at 0 power input.
This can be an advantage on some "belly landers" as the prop would not be turning as it touched down.

Most of the ESC's have a "hard" brake setting which might damage a gear drive system.

I always disable the brake feature on my ESC's, or buy ones that don't have a brake.

Bill
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Old Nov 26, 2003, 10:19 PM
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Near Austin
Joined Dec 2001
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Regardless of whether you have a folding prop or not, a free wheeling prop is nothing but drag. It's like going down a hill and putting your car in first gear and letting the clutch out. You have an engine brake. If you like to glide a long way and use your L ratio- (<- HA! That was supposed to be Liftrag ratio and it put a smiley in there!) to it's highest, then set the brake ON.

CTF
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Old Nov 26, 2003, 10:32 PM
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headless's Avatar
Tallahassee, FL
Joined Sep 2003
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the brakes i have seen on escs have caused alot of gear stripping... i turned it off (and bought another esc that has none) and those gears almost never strip. (Read: only in crashes)
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Old Nov 26, 2003, 11:03 PM
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Donald Duck's Avatar
Fort Collins, Colorado
Joined Mar 2002
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Turn off the brake to allow the prop to turn and help slow the plane for landing. Makes a big difference for some planes.
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Old Nov 27, 2003, 07:22 AM
Mitch G's Avatar
Naperville, IL USA
Joined Nov 2000
1,886 Posts
A few more random braking thoughts:

Some brakes stop the prop temporarily - just long enough to cause a folding prop to fold back. So, leaving it on with a non-folding prop won't necessarily hold the prop stationary and thus cut down on drag.

But, depending on the plane, the drag of a free wheeling prop can be a good thing to help slow down on landing.

Additionally, in those cases where the brake is constant, it is better to disable it for belly landers (with a non-folding prop) so that the prop will have a better chance of moving out of the way on landing and thus avoid breaking the prop.


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Old Nov 27, 2003, 07:55 AM
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SKYPILEIT's Avatar
Novi, Michigan
Joined Nov 2002
2,248 Posts
ESC Brake...

We all know the brake is beneficial to reduce the drag of a freewheeling prop...but some e-systems will incure damage when the power is abruptly stopped...I was losing a couple teeth on the spur gears of my GP geardive/Magmayhem system when I went to cut power to land...rather than disable the brake I found that by using the throttle trim to stop the prop...resulted in longer spur gear life....and the ability to glide...without the prop spinning....
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Old Nov 27, 2003, 08:44 AM
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Ohio
Joined May 2003
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Re: ESC Brake...

Quote:
Originally posted by dulcet
We all know the brake is beneficial to reduce the drag of a freewheeling prop...
Interesting discussion. I'm not quite sure I understand the logic of a stopped prop reducing drag. I'm thinking it would increase drag more than a free wheeling prop. I set the brake on my ESC pusher prop wing and the motor fell off when I was landing the plane. I attributed the stopped prop as greater drag than a free wheeling one. Can one of you more experience RCer's set my thinking straight?

I understand when you slow the speed control quickly the prop will be turning much less than free wheeling thereby increasing the drag until the plane speed is consistent with the prop speed. At that point there will be no drag.

Ed
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Old Nov 27, 2003, 09:07 AM
Mitch G's Avatar
Naperville, IL USA
Joined Nov 2000
1,886 Posts
To help me deal with this conundrum, I was told to think of a freewheeling prop as a disk.
A disk on the nose of a plane clearly results in more drag than a stopped prop.


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Old Nov 27, 2003, 09:08 AM
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Rutherfordton, North Carolina, United States
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If you are running a fixed prop, turn off the brake. It is putting stress on the controller if the brake is engaged with a fixed prop and the airplane is moving fast enough to try and turn the prop against the brake.
Ed
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Old Nov 27, 2003, 10:11 AM
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Donald Duck's Avatar
Fort Collins, Colorado
Joined Mar 2002
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If the velocity of the free-wheeling prop is less than the speed of the plane, it will help slow the plane for landing. This depends on the pitch of the prop. A high-pitch prop won't help, but a free-wheelling low-pitch prop will act as a brake because it and the plane want to have the same velocity.
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Old Nov 27, 2003, 01:18 PM
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Savannah, Ga
Joined Apr 2002
130 Posts
Wow, and I thought it was a simple question. Thank you for your responses. Lots of informatrion in the discussion but other than stressing a gearbox and/or esc by using the abupt action of the brake and using the brake with a folding prop, I don't really understand the stopped verses freewheeling prop and drag.
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Old Nov 27, 2003, 05:44 PM
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Bill Mixon's Avatar
Georgia
Joined Mar 2002
1,685 Posts
Quote:
I don't really understand the stopped verses freewheeling prop and drag.
I think this will depend on the type and size of prop, rotational resistance in the gear drive/motor, among other things.

As an example..
An indoor flyer that I have with an IPS drive and a 14X10 GWS prop has a better glide with the prop stopped vs. it freewheeling in the air.
This is due to the prop turning slower than the air speed because of the drag created by the gear drive. So it has that "disk" effect which slows it down.

Another example..
Brushless motor with planetary drive 24X12 prop. This setup is very free turning. So in a glide it will turn the prop close in pitch speed to what the plane is flying at so drag is minimal.

Bill
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