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Feb 24, 2013, 02:17 PM
Registered User
Quote:
Originally Posted by nadine
You could post,pid settings for the craft!?
What servos you use it!?
regards
servos: http://www.hobbyking.com/hobbyking/s..._13g_0_10.html
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Feb 25, 2013, 01:52 AM
1400 watt RW Zephyr
matwelli's Avatar
Quote:
Originally Posted by native18
CG location is below the axis of rotation of rotors.
55cm length of the model
Weight 620g
screws 9x4x3
flight controller MultiWii Lite v1.0 (Bi)
motors - D2822/14 1450KV
battery 2S 3000
thanks for that, can you tell be how far below the motor pivot point the CG is ?
Feb 25, 2013, 11:32 AM
Registered User
Quote:
Originally Posted by matwelli
thanks for that, can you tell be how far below the motor pivot point the CG is ?
The photo shows that motors are deployed down. Screws further. Ideally, the CG must be below the screws. My model is at CG screws.
Sorry, my English is not their native language.
Feb 25, 2013, 01:40 PM
Registered User
Ran D. St. Clair's Avatar
It doesn't matter if the screws (propellers) are up or down. Either way, the thrust line is through the pivot point. What matters is the location of the pivot point relative to the C.G. I think you have effectively answered that question.

Thanks.
Feb 25, 2013, 06:00 PM
Registered User
v22chap's Avatar
I love native 18 's reverse engineering on the motor pivot points ... using a blade grip the wrong way around is a really neat idea ....
It took me quite awhile studing the picture to pick up on that ,,, enlarging also helped !!!

This would work great on tricopters also ,,, it will be filed away for future use
Thanks for sharing
Feb 25, 2013, 10:37 PM
Registered User
Ran D. St. Clair's Avatar
It certainly is a great looking thing. 10 out of 10 points for style!
Feb 26, 2013, 04:04 AM
Registered User
VTOLicious's Avatar
Quote:
Originally Posted by Ran D. St. Clair
It doesn't matter if the screws (propellers) are up or down. Either way, the thrust line is through the pivot point. What matters is the location of the pivot point relative to the C.G. I think you have effectively answered that question.

Thanks.
True, thrust line is always through pivot and adequate pivot-CG-distance is crucial.
But it does matter if the motors are pointing up or down if the nacelles are not balanced itself - consider the weight shift! Dependent in which direction they are mounted the (longitudinal) CG will move with or against the desired pitch movement.

Rgds Michael
Feb 26, 2013, 08:34 AM
Will fly for food
ilektron's Avatar
Quote:
Originally Posted by VTOLicious
True, thrust line is always through pivot and adequate pivot-CG-distance is crucial.
But it does matter if the motors are pointing up or down if the nacelles are not balanced itself - consider the weight shift! Dependent in which direction they are mounted the (longitudinal) CG will move with or against the desired pitch movement.

Rgds Michael
This is true. I noticed with my bicopter if I let it hang by the arms, and disturbed it with the motors powered down, it would oscillate almost indefinitely. When I reverses the gain to be backwards, I could get it to almost immediately dampen out a disturbance.
Feb 26, 2013, 11:32 AM
Registered User
Ran D. St. Clair's Avatar
Quote:
Originally Posted by VTOLicious
True, thrust line is always through pivot and adequate pivot-CG-distance is crucial.
But it does matter if the motors are pointing up or down if the nacelles are not balanced itself - consider the weight shift! Dependent in which direction they are mounted the (longitudinal) CG will move with or against the desired pitch movement.

Rgds Michael
Good point - R.D.
Feb 27, 2013, 05:37 PM
Registered User
rimshotcopter's Avatar
Actually, there are a number of factors that goes into determining where the CG is on a Bicopter. 1. If it is an OAT or FAAT, 2, How high the props sets above the Spar and 3, the angle of rotation are the most important ones.
Feb 28, 2013, 12:19 AM
Registered User
Quote:
Originally Posted by rimshotcopter
2, How high the props sets above the Spar and
This is high enough? This model flies much better Gress Aero.
Feb 28, 2013, 12:37 AM
vtol fan
nadine's Avatar
Quote:
Originally Posted by native18
This is high enough? This model flies much better Gress Aero.
Native18,where is located the mwc board and the battery!?I never seen one foto of this...
Cheers
Feb 28, 2013, 12:40 AM
vtol fan
nadine's Avatar
Quote:
Originally Posted by rimshotcopter
Actually, there are a number of factors that goes into determining where the CG is on a Bicopter. 1. If it is an OAT or FAAT, 2, How high the props sets above the Spar and 3, the angle of rotation are the most important ones.
What is mean,OAT and FAAT !?...sorry my ignorance
At point 3,can you make one drawing?!
Regards
Feb 28, 2013, 07:07 AM
vtol fan
nadine's Avatar
Hi native18.
How far down is your cg from propps!?
I attached on foto also...What dim.have there!?
PS.hope matwelli,d'ont kill us,for highjacking his thread
Regards...
Feb 28, 2013, 07:50 AM
Registered User
Quote:
Originally Posted by nadine
How far down is your cg from propps!?
CG just below the screws. Bending aluminum tube made ​​in order to raise the screws above the cab soldiers.
Photo provisions battery and controller I will later.


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