DIY Frictionless Propeller Balancer Over the years I've become really fed up of propellers that are out of balance. So, some time ago, I bought a prop' balancer. It was the type with four large plastic wheels on which rested a spindle with two adjustable tapers to center the propeller being balanced. It cost about a fiver if I remember correctly. It never did work very well. You could put a prop' on it and maybe the left blade would hang low, but if you lifted it off for a moment and span the wheels around and tried again it was just as likely to drop the right blade! I used to take an average of which side dropped the most to figure which one to give another coat of varnish. Looking back, it was practically useless! You could hang the spindle in your fingers for a better result, but there was still too much friction for any real accuracy. If you've ever had a model that buzzes you'll no doubt be interested in making one for yourself. I've had some models where there's so much high frequency vibration they were almost painful to touch! Not good for your receiver or servo's is it? So make yourself one of these... The Perfect Balance! Computer hard drives contain very slim, powerful magnets. The magnets on my balancer came from one of these. If you've been into computers for a while you'll almost certainly have a dud or small old hard drive that you can strip for the magnets. If you don't have one already you can buy a dud drive for a couple of pounds at a computer fair. Other sources that spring to mind are magnets from small speakers as in headphones etc. They do need to be pretty powerful though. The scheme on the left shows the general layout. All you need is some kind of block to screw the wood, aluminium or plastic uprights to. I used a nice block of hardwood and aluminium uprights. (Would you believe I found a chunk of wood in my garage that was the EXACT size in every dimension! All I had to do was sand it up a bit!) The magnets from a hard drive will already have mounting holes in the backplates so you can screw them to your uprights, but if you have just the magnets then you could glue them into position. Make sure they line up fairly well. How tall you make it will depend on how big a prop' you're going to want to balance. Mine is 7" tall and, as you can see in the photo', is balancing a 20" prop'. The distance between the uprights is governed by the length of the spindle you have. The gap between the magnets wants to be no more than 1 to 2 mm greater than the spindle length. When all is done drop the spindle between the magnets. You'll find that one end of the spindle is in contact with a magnet while the other end floats magically in space! If the end of the spindle is ground to a point then the whole thing is virtually frictionless and will be the most accurate balancer you'll ever have.  If you're trying to balance glass blades then paint the tips and add coat(s) to the light blade tip. For wood, just varnish the light blade. It's a rewarding project to make and serves a useful purpose and saves you twenty quid and looks better than the plastic things you can buy. So get to it! G :-)