lopflyers

My Feedback: (12)

Since I first started flying I was told the props and spinners needed to be balanced. To be honest I thought my instructor was too compulsive.
How a prop can come from the factory unbalanced? How much difference a few grams can make?
Since I'm 53 and have a college degree I didn't see the need to scratch a perfectly shinny brand new prop.
Well I bought a new 120 Thunder Tiger, no matter how tight I put the muffler I'd come loose after a few flights, red thread lock, blue thread lock, RTV.... Nothing worked, I tried so many times that I ruined the muffler. Yesterday I tried the new muffler on and find out that there are two loose screws in the cylinder head.
When I was telling my old instructor all these failures he look at me weird and asked me if I have balanced the prop?
of course.......not. Well it was new but so unbalanced that was causing vibrations that ruined one $65 Pitts muffler and almost a brand new TT 120.
Guess where I went today? Straight to the hobby shop for a balancer........ Moral, trust the experts.

skoda450

Good advice and so true. I ALWAYS ballance my props but I have never figured out how to ballance a spinner. All the ballancers I know of require the shaft to go through the item being ballanced. I suspect spinners need it as well but I don't have a clue...

lopflyers

My Feedback: (12)

Me neither

cutaway

In the last 30 years or so, I've had under a dozen props that came off the rack and were balanced OK when checked.

mickey t

You'd be surprised how unbalanced some spinners can be. An easy way to balance spinners is with the Du Bro balancer, IMO THE best balancer around. Couldn't figure out how to post a picture, so just use the link.

MT

http://www.redrockethobbies.com/v/vs...s/DUB499-2.jpg

piper_chuck

My Feedback: (12)

To post a pic you need to use one of the reply buttons rather than using the Fast Reply box at the bottom. Once the reply window opens, use the "Click here to upload images and files" link at the bottom to add a picture to the thread or link to a picture by clicking the little yellow box with a mountain that's a few icons over from the font and size pulldowns above the text box. That will bring up a second window in which you can paste the url to the picture. Note that Iprefer to add the picture to the thread, first method, because then it's in the RCU database. When people link to a picture that's somewhere else they rely on the picture staying out there. Far too often the picture is removed from the other site and then the thread loses value.

mickey t

Thanks piper chuck, has been noted.

MT

lopflyers

My Feedback: (12)

After looking at the pic I still can't get how to balance the spinner?

skoda450

Chuck,
Thanks for the pic. I guess I never thought of cantilivering the spinner and attaching it by the backplate. I guess I have a box full of ballancing to do over the winter

Off topic, hows the boat racing been for you lately. Still kicking Don Ferretti's butt on occasion?

raptureboy

Here you go http://www.rcuniverse.com/forum/m_11...tm.htm#1115188 good thread.

lopflyers

My Feedback: (12)

Hey, that was very informative, it looks like a lot of work but worth it. Thx a bunch

gsoav8r

My Feedback: (6)

Looking at the props on the Du Bro balancer, note the cones/pieces that press onto the rod to grip the prop. Those can be used to grip a spinner or just a nose cone or back plate as well.

All props, spinners (nose cone and back plate) should be checked for balance. Doesnt matter who or how they are made. Every manufacturer can have an off day and produce some less than good stuff.
For example, I had a plane that came with an aluminum spinner and back plate. Because of the way the nose cone got attached I could check the balance of the two parts separately. The back plate was a machined part and was in balance. The spinner thou was a cast part and was out of balance big time. Used a Dremel to remove material inside the cone.
When balancing a nose and spinner together, like pictured above, mark the parts somehow so they can be put aligned and put together the same way every time. Otherwise it will be possible to put the spinner together and it be out of balance again.

Cheers.