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Old Dec 08, 2010, 12:28 PM
Registered User
Ironbridge (UK)
Joined Jan 2009
3,965 Posts
hi,

are kda 20-22's ok with apc 12x38 props on a quad upto about 2kg auw? i did a search but couldnt find much info.
cheers.

Josh
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Old Dec 08, 2010, 02:09 PM
Registered User
Stavern/Larvik - Norway
Joined Dec 2008
797 Posts
Quote:
Originally Posted by Joshbb View Post
hi,

are kda 20-22's ok with apc 12x38 props on a quad upto about 2kg auw? i did a search but couldnt find much info.
cheers.

Josh
Hi

From personal experience, the kda 20-22's don't like those big props that much. Its no problem going up and doing a hover, but when descending you got a problem. The motors have low torque, meaning they will have difficulty slowing down. This gives unstable descends and you will even find that you will have problems getting the craft down if the wind is strong. Basicly you have to use alot of athority on the throttle stick.
The kda would be a good choice for a lighter craft (-1.5kg) since they are limited to 3s (by hk specs) on 10" props.
So you should rather try to go with a motor that can handle 4s and use 10" props if you are using bl-ctrl 1.2 - best option here that i know of is 2217/20 motors like turnigy/axi etc.
If you have the new bl-ctrl 2.0 you can go for a 35-xx size motor on 12" props.
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Old Dec 08, 2010, 02:28 PM
Registered User
Ironbridge (UK)
Joined Jan 2009
3,965 Posts
Quote:
Originally Posted by robin4 View Post
Hi

From personal experience, the kda 20-22's don't like those big props that much. Its no problem going up and doing a hover, but when descending you got a problem. The motors have low torque, meaning they will have difficulty slowing down. This gives unstable descends and you will even find that you will have problems getting the craft down if the wind is strong. Basicly you have to use alot of athority on the throttle stick.
The kda would be a good choice for a lighter craft (-1.5kg) since they are limited to 3s (by hk specs) on 10" props.
So you should rather try to go with a motor that can handle 4s and use 10" props if you are using bl-ctrl 1.2 - best option here that i know of is 2217/20 motors like turnigy/axi etc.
If you have the new bl-ctrl 2.0 you can go for a 35-xx size motor on 12" props.
thanks for the reply Robin, I guess the 20-22's will stay in my spares bin then
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Old Dec 08, 2010, 05:02 PM
Mikrokopter Australia ;-)
simonjardine's Avatar
Australia
Joined Apr 2008
1,440 Posts
Under Voltage

Customers who bought a v2.1 FC between end of 10.2010 and now.
Should check the following....
Some FC V2.1 are assembled with a 3,3V voltage reference instead of the default 3,0V.

This is IC7 on the FlightCtrl.
You can follow this link for better reference.
http://www.mikrokopter.de/ucwiki/en/...oltageSettings

I would recommend updating to V0.82b for anyone who has a V2.1 FC

Simon

p.s
if you have been seeing very short flight times before the undervoltage warning appears, this is probably the cause.
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Old Dec 08, 2010, 06:11 PM
Registered User
Austin, Texas
Joined Apr 2009
499 Posts
Balance and yaw

I have a question about balance and yaw.
I have a new quad that is having some major yaw issues...but not all the time. I think it might have to do with my weight distribution...but I wanted to get other opinions.

I have it configured in X mode and when flying without the camera...I have the battery directly centered...and no yawing issues.

It's when I put the camera on that I have issues. I have it mounted straight out front in between the two front arms and I have the battery mounted on the back between the rear two arms to counterbalance the camera weight.
I have it perfectly balanced front to back and side to side...but my weight distribution is obviously way heavier on the Y axis than on the X axis. I don't know if this weight differential is what is causing unexpected yawing...or if perhaps it could be more related to weathervaining.

My goal was to keep everything up on the same horizontal plane as the arms so I don't have to use landing gear, like I do on my other copters that have the camera directly centered underneath (with no yaw issues).

Any thoughts?
Could there be a parameter setting that might off-set some of this yawing?

Thanks Guys,
Brent
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Old Dec 09, 2010, 12:48 AM
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Creteil, France
Joined Nov 2003
474 Posts
Quote:
Originally Posted by dmsgodeep View Post
I have a question about balance and yaw.
...
Any thoughts?
Could there be a parameter setting that might off-set some of this yawing?

Thanks Guys,
Brent
I have no direct answer to your question but have you noticed those new parts, supposed to improve Yaw control?

https://www.mikrocontroller.com/inde...020b124afef51c
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Old Dec 09, 2010, 09:19 AM
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Dallas, TX
Joined Aug 2008
86 Posts
Quote:
Originally Posted by Joshbb View Post
thanks for the reply Robin, I guess the 20-22's will stay in my spares bin then
I too can attest to the fact that the 12's will work on the KDA 20-22Ls, but descents are not good at all. I fly 20-22s and have run both the 10 and 12 inch APCs. The 10's have been much better for me.
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Old Dec 09, 2010, 09:51 AM
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Joined Sep 2008
705 Posts
The bar continues to rise:

Quadrotor Ball Juggling (a Preview) (0 min 38 sec)
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Old Dec 09, 2010, 10:02 AM
The tattoo guy
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USA, MN, St Paul
Joined Jun 2009
600 Posts
Quote:
Did you ever try flying it with he wooden props as in the other photo?
Jim,

No, they are just for show....
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Old Dec 09, 2010, 11:20 AM
Registered User
Solihull, England
Joined Jun 2004
961 Posts
The ESC will not absorb energy from the motor/prop to slow it down so fitting a larger prop with more inertia will take longer to decelerate.

Peter
Quote:
Originally Posted by vfrjeremy View Post
I too can attest to the fact that the 12's will work on the KDA 20-22Ls, but descents are not good at all. I fly 20-22s and have run both the 10 and 12 inch APCs. The 10's have been much better for me.
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Old Dec 09, 2010, 12:31 PM
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Denmark, Capital Region of Denmark, Copenhagen
Joined May 2010
1,157 Posts
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Originally Posted by Peter Seddon View Post
The ESC will not absorb energy from the motor/prop to slow it down so fitting a larger prop with more inertia will take longer to decelerate.

Peter
Yeah, this will hopefully be the next step in the BL's... Breaking until the desired speed has been reach...
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Old Dec 09, 2010, 08:06 PM
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Florida
Joined Dec 2009
71 Posts
Just got my "Y" frame for a Co-axial I am building, it is a nice 72 cm motor to motor. This thing is Amazing!! Strong as an ox, light as a feather. Should haul just about anything.
I want to use a UAVX but unsure if it can handle a Y frame config.
Anybody try this yet?
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Old Dec 10, 2010, 03:45 AM
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Solihull, England
Joined Jun 2004
961 Posts
And what will you do with the energy that needs to be dissipated ? Dump it to heat or back to the battery ? A Lipo may not like such charging pulses.

Peter
Quote:
Originally Posted by wizprod View Post
Yeah, this will hopefully be the next step in the BL's... Breaking until the desired speed has been reach...
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Old Dec 10, 2010, 08:18 AM
Eduardo
Brasil, RS, Porto Alegre
Joined Aug 2008
461 Posts
frame

hello brother ... where you bought this frame ?

its amazing ...

Quote:
Originally Posted by crashcam View Post
Just got my "Y" frame for a Co-axial I am building, it is a nice 72 cm motor to motor. This thing is Amazing!! Strong as an ox, light as a feather. Should haul just about anything.
I want to use a UAVX but unsure if it can handle a Y frame config.
Anybody try this yet?
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Old Dec 10, 2010, 09:06 AM
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Denmark, Capital Region of Denmark, Copenhagen
Joined May 2010
1,157 Posts
Quote:
Originally Posted by Peter Seddon View Post
And what will you do with the energy that needs to be dissipated ? Dump it to heat or back to the battery ? A Lipo may not like such charging pulses.

Peter
I have no idea... I just know, it would be nice to have... I will let others do the engineering, it's safer that way :P
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