adding weight to the front

I use lead fishing sinkers from Walmart. About 10 cents an ounce. Sometimes I have to pound them to a special shape and other times I have to cut them into little pieces and glue in place with epoxy. Once I had to add eight ounces to each nacelle of a twin scale plane. I bolted them to the motor mounts and painted them yellow to look like they belonged to the engine such as an oil tank. Good luck Gene

Simple solution might be a solid spinner instead of the plastic two part spinners. John

Current thinking is to not add weight to the engine shaft. Bad for the bearings, and for the plane's handling.

-- Jim in NC

So the spinners that nubro sells is bad for the engine. I know that when I put my voyager together I put one of these spinners on the engine and it seemed fine but it did add enough wieght to the front of the plane to have to move the battery aft of where I may have put it otherwise. I would think that you would see more comments on these spinners if they were not good for the engines or the manufactures would put something in the owners manuel that the warrenty is voided if you use something like this. John

Do a google search for weighted spinner nuts, and I think you will see I am not the only one to write this.

The engine will not self destruct, but it may take some life off the bearings. That too is of little issue, since most engines self destruct from crashes, neglect or abuse, much sooner than they should die. IMHO, weighted nuts are one more form of abuse, that can easily be avoided by weighting the engine mount. In your case, you could have made the airplane lighter, by using a lighter spinner, less weight, and keeping the battery forward.

-- Jim in NC

| So the spinners that nubro sells is bad for the engine. I know that when I | put my voyager together I put one of these spinners on the engine and it | seemed fine but it did add enough wieght to the front of the plane to have | to move the battery aft of where I may have put it otherwise. I would think | that you would see more comments on these spinners if they were not good for | the engines or the manufactures would put something in the owners manuel | that the warrenty is voided if you use something like this.

I doubt it's really *that* bad. Yes, it puts a little extra weight on the shaft that will be pulled down by gravity, but I doubt it causes the bearings to wear much faster. And if they do wear out (before the rest of the engine!), they're not hard or expensive to replace ...

As for bad for handling, are people thinking of the gyroscopic effects? If so, since all the weight is right near the center of the shaft, the gyroscopic effects will be small compared to those of the prop.

And of course it depends on which Dubro spinners you're talking about. Some are aluminum and very light, and some are steel and quite heavy :)

... | > Current thinking is to not add weight to the engine shaft. Bad for the | > bearings, and for the plane's handling.

I cant help but ask, what plane are you putting this weight on? Picking the middle of your range of weight needed, say 8 oz, thats half a pound! Can you put the battery under the tank and move the rx forward instead? Its always best to move the components you *need* for the plane (battery, receiver, etc.) around for balancing instead of adding dead weight whenever possible. Tail heavy? Move the battery and rx to the rear. Nose heavy? Move the battery and rx to the front. Adding lead comes after you have moved whatever you can move.

Mix the smallest lead shotgun shot with 30 min epoxy. Fill the farthest forward part of the fuse till it balances.

Regards

Tom Watson Sydney Australia

exactly bass ackwards! Is that how you got the name fubar? (big grin) with flame suit on. George J.

| It is a Aluminum spinner, and the reason I wanted it instead of the two | piece is because the start I have leaves marks on the plastic piece and with | th Al spinner I get a better grip for starts.

Oh, then if it's what I'm familiar with, it's only a bit heavier than the cheap plastic spinners. It won't hurt anything.

An added bonus is that it's much less work to swap out a prop :)

Only real downside is that in a crash into something hard it won't absorb any of the impact like a plastic spinner would.

I have left over from building my hose, a roll of lead flashing.

Its easily cut with scissors, its flat sheet about 1mm think.

I have also melted solder with a blowlamp and cast it, and scrounged used car wheel balancing weights for free off the local tyrefitters.

problem is balancing em. out of balance spinner makes for vibration and front bearing falure.

If you have tried moving the battery as far forward as possible and everything elde inside the plane, i usually use the stick on mag wheel balancing weights. After sticking them on, I coat the foam with some epoxy to keep the oil from loosening the adhesive.

Well balanced weight on the shaft won't hurt the bearings. Unbalanced weight will hurt everything!

Many cheap ARF trainers come out very tail heavy with a plain bearing engine on the front. One way to cure this is to use a heavier engine like a four stroke.

"Paul McIntosh" kirjoitti viestissä news:bjuoep$qk7$ snipped-for-privacy@sparta.btinternet.com...

I use balancing lead weights for motorcycles, the kind that has some kind of double sided tape on them. They are real nice blocks of weights with the weights stamped on them, like 5g, 10g and so on (you probably get them with different weight units). I buy these from car and motorcycle spare parts stores and they don´t cost much. Guess these are almost the same that Paul is talking about.

Cheers, Ken Finland

| > | So the spinners that nubro sells is bad for the engine ... | > | > Current thinking is to not add weight to the engine shaft. Bad for the | > | > bearings, and for the plane's handling. | | problem is balancing em. out of balance spinner makes for vibration and | front bearing falure.

Are we talking about the same thing? The spinners I'm thinking of appear to be extremely high precision milled aluminum, like this --

I'd expect these to be just about perfectly balanced already. Certainly, I'd expect them to be better balanced than the plastic ones.

Also, they are a good deal smaller than the plastic ones, and since all the weight is so much closer to the center of the shaft, I'd expect any vibration caused to be much less. The smaller it is, the less vibration being out of balance can cause (because the vibration is proportional to the distance from the center that the disportionate weight is. Or is it the square of the distance?)