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Old Mar 05, 2013, 04:12 PM
RTFM // copter damaged
warthox's Avatar
Joined Aug 2009
1,726 Posts
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what happens if you change rotation direction of the props midflight? [fp 3D quad]

this!

mwc quad // ultraesc 3d (2 min 53 sec)


my first cautious attempts to fly a 3d capable quad


experimental ultraesc fw.
modded mwc fw [oneshot + 3d] for nanowii board.
modded 8x4.5" cf reinforced props.

ultraesc setup:
- input pwm 125-250Ás oneshot
- motor pwm 32khz
- active freewheeling enabled [synchronous rectification]

more info http://www.rcgroups.com/forums/showthread.php?t=1799000
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Old Mar 05, 2013, 04:14 PM
Mmmmmmm!
WiseDuck's Avatar
Kingdom of Sweden, Dalarna County, Sater
Joined Oct 2011
3,353 Posts
Alright, that is cool.

I want ALL the info needed to make this work!
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Old Mar 05, 2013, 04:16 PM
Need more props..........
Oso Grande's Avatar
United States, TX, Houston
Joined Jan 2013
1,912 Posts
Wow
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Old Mar 05, 2013, 04:21 PM
Don't panic!
Canada, ON, Mississauga
Joined Feb 2013
390 Posts
Just a thought - as it is being widely considered, quad it doomed once 1 motor is out.

With reversing motors, could the quad land more safely with opposite motor able to reverse to compensate failed side going down?
Considering the fact that even 2 motors combined have enough power to at least decrease negative vertical speed?

By the way, are there any copters with variable pitch rotors?
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Old Mar 05, 2013, 04:35 PM
Out of helis, sanity returning
Tallahassee, FL
Joined Feb 2009
2,147 Posts
Bravo! Beautiful innovation.
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Old Mar 05, 2013, 04:36 PM
Head full of foam
United States, NE, Omaha
Joined Jan 2013
324 Posts
OK, stupid operational question:

Does the FC do that automatically? As in, you get it upside down, the FC senses it's new attitude and it turns the props backwards to hover upside down. Or is this something you have to do on the remote, like flip a switch?
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Old Mar 05, 2013, 04:37 PM
Don't panic!
Canada, ON, Mississauga
Joined Feb 2013
390 Posts
Quote:
Originally Posted by RuralFPV View Post
OK, stupid operational question:

Does the FC do that automatically? As in, you get it upside down, the FC senses it's new attitude and it turns the props backwards to hover upside down. Or is this something you have to do on the remote, like flip a switch?
Or you throttle stick has zero in the center, not at the bottom?
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Old Mar 05, 2013, 04:42 PM
Since 1902. Maybe.
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France, RA, Grenoble
Joined Dec 2004
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I guess the throttle stick is simply set with zero at THR 50%, same as you would control the ESC for a buggy....
With maybe a little bit of dual-rate for the "reverse", since the props won't be as efficient.
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Old Mar 05, 2013, 04:50 PM
RTFM // copter damaged
warthox's Avatar
Joined Aug 2009
1,726 Posts
Quote:
Originally Posted by RuralFPV View Post
OK, stupid operational question:

Does the FC do that automatically? As in, you get it upside down, the FC senses it's new attitude and it turns the props backwards to hover upside down. Or is this something you have to do on the remote, like flip a switch?
v

Quote:
Originally Posted by vadimus View Post
Or you throttle stick has zero in the center, not at the bottom?
exactly.
throttle stick above center = normal rotation.
throttle stick below center = reversed rotation.
throttle stick at center = very slow normal rotation.
theres no position of the stick were the motors are stopped.

there is nothing else. its like controlling a normal cp heli.
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Old Mar 05, 2013, 05:13 PM
Blacked out 350z - Texas
Wrice4's Avatar
Joined Nov 2012
1,838 Posts
Quote:
Originally Posted by warthox View Post
v



exactly.
throttle stick above center = normal rotation.
throttle stick below center = reversed rotation.
throttle stick at center = very slow normal rotation.
theres no position of the stick were the motors are stopped.

there is nothing else. its like controlling a normal cp heli.
You sir.......ROCK.
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Old Mar 05, 2013, 05:41 PM
serial scratchbuilder
Granted's Avatar
Canada, BC, Mission
Joined Sep 2012
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I see a new breed of props in our future.
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Old Mar 05, 2013, 06:18 PM
Registered User
United States, AZ, Tucson
Joined Mar 2008
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Totally awesome ! ! !
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Old Mar 05, 2013, 06:21 PM
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United States, KS, Overland Park
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brilliant!
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Old Mar 05, 2013, 06:21 PM
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Long Island, New York
Joined Jun 2008
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Wow, this is a game changer,awesome work.
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Old Mar 05, 2013, 06:43 PM
hacker
Canada, BC, North Vancouver
Joined Dec 2010
936 Posts
Hello!

I tried to do this early last year, since I added support for this in my tree since Nov 3, 2011, but found that most slow flyer props really suck at reverse thrust (pun not intended). I ordered some non-scooped props from Fancy Foam Models, as I recall, but never ended up getting them, and then forgot to try again. If flat is not available, higher pitch props probably work better. The ones warthox is using there seem to work but don't sound very happy.

For doing this with my code, you just need to set RC_PULS_REVERSE to 1 (which enables RC Car type mode) and perhaps adjust the endpoints, or calibrate them like with an RC car ESC. It will work on any board including without complementary PWM, though complementary PWM does actually help a bit with back-EMF detection and could probably flip directions a bit faster. This eventually led to the start-up improvements and ZC filtering in 2011/2012 that made higher inductance and pancake motors work better and not get stuck spinning the wrong way. I tested with a 2213N with no prop and could flip from full throttle one way to the other in <100ms with COMP_PWM=0.
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