WEDJ

These tiny 4.5 x 2 props for the .020?

Mr Cox

Good question, even larger props are affected by the balance of the rig it self.

I usually use a topflite without using the black plastic centers (have tried to balance these but just leave them of now), and do the centering using a piece of fuel tube or a piece of heat schrink. I did make a new thinner rod for the balancer from music wire, but it is a bit tricky to get the wire straight. Putting the prop to one side helps but I'm not too thrilled by the solution yet...

combatpigg

My Feedback: (3)

Run the engine with the prop in question to see if you have a problem first. I don't balance props under 7 inches unless there is vibration. If a 4 inch prop was to ever be off enough to matter, I would toss it and try another. I've never come across a 6 inch or less prop that wasn't good to go.

lildiesel

I've never had a Cox grey 4.5x2 that appeared to run out of balance. Same goes for the Cox grey 6x3 and 7x3.5 that I run on .049s. Small diameter wooden props occasionally need a coat or two of clear dope on the light blade to appear to be statically balanced. These days I'm thinning the hubs of some wooden props and cropping the tips for some applications so there is a bit more work involved getting the balance right. For that I've got an old Hi-Line can motor powered from a train transformer to help with making sure props run true.

gcb

The hi-line is no longer available AFAIK. Du-Bro makes one that works on the same principle, and is probably the most accurate one now available.
I have the Top Flite magnetic one, which works great, but has limited use. Were I to get another balancer, it would be the Du-Bro.

IMHO ALL props should be balanced. A spinner should even be balanced (that's one place the Du-Bro has it over the Top Flite). I make it a point to balance new props before putting them with the other usable ones.

Perhaps I am just persnickety.

George

WEDJ

I'm liking the "try it first" line of thinking.

Thanks for all the input.

Silvaire

My Feedback: (50)

You can't argue with success...

On the other hand, whether the prop is balanced by the user or not, it does need to be in SOME state of balance to run decently.

I have even found some of the tiny props on Airhogs bipes to be significantly out of balance. These will balance up nicely with a sewing needle and a Top Flite magnetic balancer though. (They need to have the CA removed with a drill bit first, and finding a good straight needle of the right diameter to use as a mandrel can be a bit of a search.) You can hear how sweetly they "sing" coming out of a dive vs. those that have not been balanced.

RocketRob

My Feedback: (1)

The cox .010 3x1.25 props get trimmed and rebalanced on a jig made up from razorblades and a suitable music wire.
Actually works very well and quite helpfull on these engines spinning 26k +.