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Old Mar 05, 2013, 04:12 PM
warthox is offline
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Discussion

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 https://www.rcgroups.com/forums/show....php?t=1799000
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Old Mar 05, 2013, 04:14 PM
WiseDuck is offline
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Mmmmmmm!
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Alright, that is cool.

I want ALL the info needed to make this work!
Old Mar 05, 2013, 04:16 PM
Oso Grande is offline
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Need more props..........
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Wow
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Old Mar 05, 2013, 04:21 PM
vadimus is offline
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Don't panic!
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?
Old Mar 05, 2013, 04:35 PM
2400RDR is offline
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Out of helis, sanity returning
Bravo! Beautiful innovation.
Old Mar 05, 2013, 04:36 PM
RuralFPV is offline
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Head full of foam
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?
Old Mar 05, 2013, 04:37 PM
vadimus is offline
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Don't panic!
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?
Old Mar 05, 2013, 04:42 PM
Olivier_C is online now
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Since 1902. Maybe.
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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.
Old Mar 05, 2013, 04:50 PM
warthox is offline
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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.
Old Mar 05, 2013, 05:13 PM
Wrice4 is offline
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Blacked out 350z - Texas
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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.
Old Mar 05, 2013, 05:41 PM
Granted is offline
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serial scratchbuilder
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I see a new breed of props in our future.
Old Mar 05, 2013, 06:18 PM
jasper7821 is offline
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Totally awesome ! ! !
Old Mar 05, 2013, 06:21 PM
serrated is offline
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brilliant!
Old Mar 05, 2013, 06:21 PM
Tarro is offline
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Wow, this is a game changer,awesome work.
Old Mar 05, 2013, 06:43 PM
simonk is offline
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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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