Balancing props - RC Groups
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Nov 02, 2011, 11:54 PM
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Balancing props

--TIP 1: Balancing props and motors is important for reducing vibrations which can interfere with gyros and accelerometers and cause fuzzy photos and video. Magnetic balancers are best for static balancing props. There are various techniques for dynamic balancing of the prop and motor combination, such as the procedure suggested by OMM here: Prop balancing video tutorials: prop balancing video tutorial (5 min 5 sec)Prop balancing thread:
--TIP 2: One often overlooked cause of vibrations after the motors and props are properly balanced is prop tracking. Check the props from the sides, if the blades are not in the same plane when spinning, that will cause some vibrations and possible oscillations in your model. Some props are just warped and need to be replaced. The centering of the prop hole is also important to eliminate vibrations. If your prop is not tight on the motor shaft and centered, it will cause vibrations.
--TIP 3**WARNING: Sand and round the prop blades to remove the very sharp manufacturing flashing to reduce the possibility of extremely severe cuts. Jesolins prop info:
--TIP 4: Also see the Vibration Solutions in this index.
--TIP 5: I prefer collet adapters that clamp over the set screw type for the best reliability. The reliability trick for collet adapters is to first roughen up the motor shaft with sandpaper or an emery board, then use an old prop and really tighten the collet on the motor shaft first. Tightness suggestion is finger-tight, then 1/2 turn for this initial tightening. Use finger-tight and 1/2 to 2/3 of a turn for mounting flight props. Do not use a new prop as the initial collet tightening process can weaken the hub and cause cracks. Use Lok-tite and flat thin washers the width of the hub and a locknut for the best insurance of the prop staying tight. Do not use lock-washers as they will stress the hub and cause cracks. Do not use prop-savers on high cost multicopters. They are prone to vibrations and rotting O-rings. They are OK for low-cost sport flying multicopters if you want to use them at all.
--TIP 6: For most tris/quads/hexa/octos the slow-fly 2-bladed type of props are the favorite for overall performance and efficiency. Tri-bladed props will work, but are not efficient and can cause oscillations.
--TIP 7: Most quads/hexa/octos use props in counter-rotating pairs. Most common normally used props on models are CCW rotation, also called tractor props. When looking at the front of the CCW rotating prop the air is propelled behind it. The common orientation is the front and rear using the CCW props and the left and right using the CW, or pusher props. This may or may not be reversible, i.e., CW props on front and rear and CCW props on left and right, in your setup utility depending on the version of quad you fly. If the front, rear, left right prop orientation is not selectable via the setup application, then the props must be mounted the way the flight control board requires them or the quad will not fly and possibly will flip when throttle is applied. The CCW(tractor)+CW(pusher) prop sets are not commonly available, but online stores do have them.
--TIP 8: With some quads/hexa/octos you can use the same standard CCW props and CCW motor direction by adding 5-10 degrees of tilt that counters the centrifugal forces of the spinning props. This is somewhat less efficient as it uses more power to maintain heading and yaw than a combination of CCW and CW props, but it does work. It does give good yaw control when setup correctly even for arm lengths in excess of 70cm motor-to-motor which is about the limit for yaw authority when 10-13" CCW and CW prop pairs are used. An example setup using only CCW props would be while looking down on the quad with the front facing away from you: the front motor would be tilted to the left, the rear motor would be tilted to the right, the left motor would be tilted forward and the right motor would be tilted to the rear. Here is a good how-to explanation by Simon:
--TIP 9: Estimaters for electric motor and prop combinations: and and and
--TIP 10: Excellent discussion on capability differences between an octo and hexa and coax and flat prop orientations:
--TIP 11: Tricopters can use common tractor/CCW props on all three motors. Some use a CW and CCW prop on each of the front motors and a CCW prop on the tail to minimize the torque steer and lean that can result from using all CCW props. This is more of a personal preference than a necessity as it will fly fine either way.
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Nov 03, 2011, 12:04 PM
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Hey guys don,t forget to also bal. the spiner if you use one. Allso on d/f s Ihave had nuts out of bal. Harold

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