Balancing - Static vs Dynamic
 

I would like to get an opinion from you guys what the general feeling is regarding blade balancing.

Should heli blades be balanced Dynamically:
Determaning the centre of mass of both the blades, getting both centres of mass perfect, then you get both blades exactly the same weight on a see-saw type balancer, by applying extra mass on the centre of mass lines.

Or Statically:
Only balancing them on a see-saw, placing extra mass on the tips.

Personally I have always balanced my blades Dynamically, but was told today that is a waste of time, seeiing that the blades are supported at the blade grips on exactly the same axis.

I must say the argument does carry weight.

Personally I ONLY believe in Dynamic balancing, but how can I proof by using physics to somebody that a set of blades that is Statically balanced, would be "unbalanced as soon as the head start turning.

Obviously there are other factors affecting balance like tracking, lift point of the two blades, etc.. but lets keep to balance.

RE: Balancing - Static vs Dynamic
 

To me it really depends most on the length of the blade. For 350mm and under I only balance statically as it makes very little difference in such a short blade. In longer blades (for 500 electric and up) I balance dynamically. It doesn't matter that the blade is fixed at the blade grip, at high rotational speeds the cog of the blade will make a difference. it's like saying a weight on the end of a string will react the same as a completely stiff blade as long as they're the same weight.

When you change the direction the blade is travelling the blade with more weight at the end will cause the blade to flex more and will affect the rotation "disk", like having untracked blades will. Remember that mass is a part of the inertia equation.

RE: Balancing - Static vs Dynamic
 

Complicated subject for sure.

I take a very scientific approach. I put them on, match the pitch and see if they track and or vibrate. If they do slap a piece of tape on one side and see if it gets worse or better.

Most (decent) carbon blades today are pretty darn close out of the box.

RE: Balancing - Static vs Dynamic
 

Dynamic even on small blades. I even check tail blades but seldom do anything with them.

RE: Balancing - Static vs Dynamic
 

i balance my blades dynamicley the only wat to do it if you ask me

RE: Balancing - Static vs Dynamic
 

I balance my blades dynamically. It's the only way to do it, if you ask me.

RE: Balancing - Static vs Dynamic
 

Dynamic except for paddles and tail blades but they do get weighed and matched to 1/100th of a gram. It's the hoola-hoop factor. Do you want your disc spinning like that or smooth as you can get it. If the CG in the baldes are at different location in the span, the masses will be different and will try to stretch out and wobble the disc off center and fight against each other which causes vibration on the main axis. Balance is balance. You may not notice it with a smaller blade but on it's level, it is vibing and vibing is bad for helicopters, linkages, bearings etc. The smoother you can get the balance the longer things will last and the smoother your helicopter wil fly, period.

RE: Balancing - Static vs Dynamic
 

I don't keep mine together long enough for it to make a lot of difference. If it ain't vibrating at lift-off speed, it's ready to go.

RE: Balancing - Static vs Dynamic
 

ouch that hurt your walet

RE: Balancing - Static vs Dynamic
 

Not too bad. Seems that tail first is a pretty good way to crash.

RE: Balancing - Static vs Dynamic
 

true that does make sence