I see all these prop balencing tools what are they for?? a prop isnt balenced when you buy it? I just dont get it thanks for the help.

I might be a bit stupid but I have never balanced a prop. I have checked them on occasion but I have seen either on the prop itself or somewhere that you are not supposed to alter the prop in any way. So I don't know about balancing but I have never had any trouble either. :confused:

Nope, props are not balanced when you buy them. Some are better then others though! I've had some Master Airscrews that were so far off it wasn't worth balancing. Some of the wood ones I have had were good, but APC's seem to be the best. Not only are they balanced, but they will give you better performance.

Why do you balance a prop? For the same reason your tires are balanced! Bad vibration can not only break the engine from the mount, but vibrate your airplane apart or screw up a reciever. Your reciever is wrapped in foam for one reason and that's vibration (and crashes). Screws can easily vribrate loose. How common is it to have an airplane fall apart from vibration? It's very rare! You really don't need to balance a prop for a .60 sized engine or smaller, but if you have a lot of vibration you know where it's coming from! When you get up to the bigger planes it becomes a bigger issue. I'd balance a prop for everything though...

If you want a better idle, smoother running engine, and all around better performance, balance your props.

OK Brian, I beleive what you are saying but how or what do you do to balance them?

not the best way but it works for me,,,

take a stiff piece of wire,, stick it through the hole,,, see which way it tips,,, take some off the heavy side till it stays even,,,
simple ,, cheap,,,

I've got a magnetic balancer, forgot who makes it. It works great though! The little finger balancers are nice too. Stop by your LHS or cruise around on the internet, there are a lot of options. There are also a few that are easy to make.

I forgot to mention that not only can the vibration damage the plane, damage can also occur inside the engine! Ever had muffler bolts or head bolts come loose? Balancing your prop can help that too!

There is a good article in the latest MAN which covers balancing 2, 3 and 4 blade props. If you get a chance to look at this article, do so, it'll explain a lot and it show pictures of a few prop balancers and where to add weight or shave off weight on a prop to balance it.

I have to admit, I usually balance them the same way as Skypup. One of these days I'll break down and get a magnetic prop balancer for the shop.

Jon :)

I made an enhanced balancer from the "cheaper fingertip model". (I have since broke down and bought the T/F magnetic model.. which is very good) I simply made a couple wood supports about 1" X 1" X 8" tall. I mounted them on a scrap piece of flat wood, and epoxied on some crossed razor blades on the top on each upright. (this formed a "V" notch to rest the tapered ends of the hand held balancer). Adjust, and then glue the uprights in place on the base when the balancer lays in the V notches the best. This is a pretty good "bearing" for free movement. IMO the fingers do not provide that free movement. As far as ways to balance.... I simply use fuel proof white paint and paint the light tip. I have run into a BUNCH of props lately that require about 1" ... to 1 1/4" of paint on the light tip just to balance. EVEN some APC's!!! :eek: This white paint also lets you see the running prop better and MAY save some stiches some day. I got in a big long discussion on one of the forums about "no need to balance 40 sized planes". The guy was VERY knowledgedable and was technically correct.... BUT... again IMO, It can't hurt to balance the 40 size, (I still think it helps):D ..... AND you gain a saftey factor with the visibility of the white / yellow paint.

"The guy was VERY knowledgedable and was technically correct.... "

I can't imagine any good answer for not balancing a prop, other then not knowing any better or just lazy. The same with leaving batteries on the charger 24 hours a day 7 days a week. You start to believe that just because you've gotten away with it that it's proper practice and then you end up with something like this. . . . .

http://www.tucsoncitizen.com/local/5_20_02plane.html

No detail or practice is to small when it comes to safety and everything you do or don't do affects the safety of you and the others around you.

lownslo, I'm guessing that person you were talking about was Christopher Dahle. He definitely knows what he's talking about and he had some great points. It's not really going to cause too much damage on a .40 sized airplane and it just adds to everything a beginner needs to learn and understand at the same time.

I honestly wouldn't tell a student he needs to go balance his prop unless it was REAL bad. After training and learning how to fly, that's a good time to talk them into balancing their props.

Oh yeah, something else I forgot to mention.

The vibration from the engine can also cause fuel foaming. Fuel foaming+engine running=engine not running. This is the reason for wrapping the fuel tank with foam. Since I brought that up I'll mention another cure for it, a few drops of armorall (sp?) in a gallon of fuel will stop it from foaming.

Hi Brian.... you are correct. It was Chris. I guess I am too pickey about most things. I do understand what you are saying with a new student.
If he is like me, and a lot of people, we sometimes read too much.;) Like I ended my debate with Chris though, if I recall correctly.... To each their own, whatever floats your boat, etc. I feel good about balancing the props on my 40 size planes. That doesn't mean I am correct, (or wrong either). There is sooooo much to learn in this hobby. I did control line flying when I was a teen and I thought I knew a few things. :rolleyes: Yeah.. right. I have been in this R/C stuff for a year now and I feel I have just scratched the surface!! I am glad you mentioned the Armoral trick. (for all to use and to remind this old goat whose memory let that one slip to the "back burner"! :D....

I guess balancing your props also helps in a psychological way. It's like sanding your new plane for a few hours and watching all that dust come off. It makes you feel like you have a real light, better, and stronger airplane then the rest, but really all you did was take off a few grams. :(

All you ever need to know about prop balancing,

http://www.bolly.com.au/book/content.htm