pro balancer
 

I am seconds away from tossing this top flight balancer in the trash. I watched more videos then I can count read the instructions 3 times. I can get a prop to balance take it off put it back on t G e exact same way and the dang thing is unbalanced again. Not to mention turning the balancing rid around with a balanced prop still attached shows the prop that was balanced facing one side is unbalanced facing the other side. Same thing if I balance both the prop and hub.

The prop balancing rod seems true but I have noticed the rod with no props on it when spun and stopped by my finger will always twitch to the same side.

I didn't like my TF balancer either. Bought a Dubro Tru-Spin and it works much better. The Dubro seems to be much more precise. Anybody want to buy a TF prop balancer?

I wish this thing just kinda worked I mean if I could get it mostly balanced great. However it's unusable as is for all I know I could be making it worse. Thank goodness I decided to add weight and not remove it so no real damage done to the prop a member on rc groups suggest air flow in the room so I will try again in the morning in a room with no air movement.

Another vote for the Du-Bro...

yup, although I love MOST top flite products... their magnetic prop balancer isn't one of them ;-/
another vote for the DuBro Tru Spin :) (I even do 50MM EDF fans with mine.)

Unless you're turning super high RPM if you get it really close then it's close enough. Really. You're talking about the magnetic balancer, right?

Yeah, but how is the OP to know whether he's close or not when he can't get a consistent reading?

Yes I could be making it worse thinking it's getting close

Make sure the hole in the prop is centered. If it isn't it will drive you crazy trying to balance the prop.


Tom

And how do we do that? And how do we fix it if it's not?

Kurt

If the shaft isn't balanced with no prop then the balancer is defective. I like the Du-Bro balancer better too since it allows you to do really big props and spinners too, but the Top Flight design is sound.

my first step for wood,props, is to maks a plug fot whole that just pushes in with finger pressure to find the center then measure to the tips to make sure the pre drilled hole is in the center ( hav found them to be off as much as 1/8 inch) span wise ie: tip to tip and the hub off 1/16, not offten but over my 40 years of flying rc .15 to G-62's and when I find one I have allways sent it back to the mfg at my expence with a polite note, and hace allways had good results generaly I have gotten 2 for 1 and a thank you note

once that is done I have used both balancers but I like thr du-bro best, and over the years I have a set of steps that works for me.
and once you have the center hols right balancing is a lot easer.

Hope this helps

Couldn't that tell you that the blades aren't the same length?

Kurt

Kurt

Yes But if you take some good measurements tip to hub mill start points, or hole center to start of mill points it can also tell you the orignal hole is not centered. been there done that but that is just me some props will balance with a drop of ca at the tip or on one side of the hub, and you can scrape the back side of the heavy plade, add acoat of rattle can clear coat on the light blade just depends on how close you want to get.

Cheers

PS I check and balance every prop I buy

I agree with everything you are saying but I think we could measure everything until we are blue in the face. I have been buying props since 1975 and have never measured the location of the hole in the hub. I balance my pylon racing props (gave up balancing sport props decades ago), but APC props are almost perfect out of the bag, from my experience. And when I have had to pull one directly out of the package and install it quickly between heats, I could not tell a bit a difference. The only time I could ever attribute a poor run due to an imbalanced prop is after a prop strike. It reminds me of an old college engineering course addressing tolerance standards and how we can introduce more errors in our data simply by our poor measuring abilities.

Kurt

APC props might be "good enough," but by the accuracy of the Du-Bro balancer every one that I have ever taken out of the package has been out of balance. Same goes for Master Airscrew. I haven't used any other brands. I take the extra few minutes to get them perfect including the hubs. It might not matter much in the grand scheme of things, but I also don't have screws rattling loose and glue joints breaking from vibration fatigue either.

Exactly. But my point was that the balancer has to have a tighter tolerance/accuracy than the balancee. Not sure I would assume this with a Du-bro. Cheers.

Kurt

For small props (glow engines .60 and below) I don't bother to balance props. I just put the heavy blade on the same side as the crankshaft counter weight). Most engines can use more weight on the counter balance side.

Ok guys maybe I should have said I am only talking about wood props, and the cutting tools have come a long ways from when I started balincing them about 40 years back. frist balancer was a bubble unit

I am not a fan of APC's except on the smaller engines, and never realy balenced them I did check a few. have given up on most other plastic props and have disposed of all of my small engines. so I am thinking 18 inch wheels and larger

But it is like I said it is just how close you feel you need to be and I like to soft mount my bigger engines just to get some of the natural vibration out of the air frames.

You do have to keep the du-bro unit clean, and if used correctly it will do a good job.
we all have to do what works for our selves

Cheers

Had the top flight now I too am a Dubro fan, the top flight made me look harder for a better mousetrap"

A magnetic balancer has close to zero drag so if the prop moves very, very slowly it is as close to being balanced as it can be. If the Dubro shows that same prop as being balanced it's probably just because the Dubro has a lot more drag with the wheels. I have a magnetic balancer that has the same trait as the Top Flite and I trust it a lot. I've never used the Top Flite though but it sounds like the same behavior as mine. If it is then it's nothing to be alarmed by.

The Du-Bro doesn't have much drag at all. I can put a 10x6 on it and get it balanced right and it will turn really slowly for several turns, probably one turn every 5 seconds for 2-3 turns. I even balance my little 6x4 electric props on it and can get a consistent reading even down to getting the hub balanced.

Yeah, I understand how it works. It's basically a rip-off of the Robart balancer. But it's still a lot more drag than a pin-point touching a magnet. Think about it this way using pretend numbers.

If a balancer held between your fingers has drag of 10 and a magnetic balancer has drag of .001 then the finger balancer has 10,000 times more drag than the magnetic balancer. If the Dubro balancer has only .1 drag then it's still almost zero drag but 100 times more than the magnetic balancer.

On a magnetic balancer, if the propeller is exactly balanced and you lay half an eyelash on a blade near the hub that blade will drop pretty fast. On a 30K rpm motor a propeller that amount out of balance wouldn't be any problem at all.

There may or may not a difference at the minutely tiny number's you're talking about. I certainly don't have the equipment to measure the friction and compare the two. I do know that the Du Bro can sense a hub that is one little dot of CA from being in balance. Given the leverage that a hub has versus a blade, I'm confident that the Du Bro balancer is capable of getting the blades perfect and the hub very nearly perfect.

So Du-bro copied Robart? But Robart operates just like the original High Point Products multi-use precision balancer.

But it would appear that Robart bought the rights to the design some years back.

Aw Heck-----I am beginning to feel a little insecure bout my balancer:rolleyes:

http://www.rcuniverse.com/forum/atta...mentid=1980949

Nice John. And your shop is so clean.

Kurt

OK. I thought the High Point was just a trade name of Robart's. My main point is that it's balancer that uses gear leverage which has more drag than magnetic suspension. The only reason I used the word "rip off" was to indicate that I understand the principle behind the balancer.

I haven't said and should have that there very well may be a problem with the Top Flite balancer. I'm not claiming there isn't. But it could be people are getting worked up over the fact that a magnetic balancer will reveal an even smaller out-of-balance condition than a Dubro balancer will. If that's what's going on it's a good thing, not a bad thing.

John - I know you know this, but newer folks might not - that type balancer WAS state of the art before the High Point. I had a couple of those and they were and still are more than adequate.

Okay so to take this all in if it moves vert slow that's good enough.

That's my attitude. If you notice any symptoms in your plane that can be cause by vibration then revisit prop balance. If the glow plug is blurry that's a good indicator. Usually the engine runs rougher at lower throttle settings and that has a lot more to do with the engine than the propeller. An easy way to tell is just run a spinner with no prop at idle. Won't hurt the engine as long as you don't throttle up. I used to polish aluminum spinners that way. :D

Me Too, I do not normally balance propellors on the majority of my aircraft unless it is called for by excessive vibration. I do however for some of my higher performance or competition airplanes and a few of the bigger ones.

My first post was somewhat 'tougue in cheek' but I Have somehow hung on to the little razor blade in a balsa block balance widget well a long time.

I do have others including the magnetic, The Sig CG, prop balance kit was interesting that I put together when I was recuperating from some medical problems and it was a pleasant diversion that I could do in bed and a building board. it does use the wheel type and works well but with some difficulty due to the clutter of the airplane balance device portion.

In the Picture second from the left is a wheel type that I have no clue as to its origin since it came with a 'buy out' and the one that I use the most when I choose to balance a prop since its quick and easy on a shelf. Anyone know what it is?

http://www.rcuniverse.com/forum/atta...mentid=1981584 http://www.rcuniverse.com/forum/atta...mentid=1981585 http://www.rcuniverse.com/forum/atta...mentid=1981586 http://www.rcuniverse.com/forum/atta...mentid=1981587

John

John
Your balancer in question is the same one I have. Mine is 20 years old, I thought it was the original Top Flight balancer but I could be wrong. I use mine on every propellor I buy. You can turn the legs over on one side to make a tall and short side and hang large props off the end. The spindle goes through the hole and rides on the bottom of the wheels on the tall side.

That second from the left is the Robart. You're talking about the gold anodized one, right? It should say Robart on the base but looks like it's been sanded off. The wheels are on I think 1/32" wire axles.

:D CafeenMan has it exactly right! I had forgotten about that balancer...
http://www.rcuniverse.com/forum/atta...mentid=1981591

Hmm went out and double checked Yes it is exactly like the picture AMA, There was a sticker on the top of the base but gone long ago, but there is tiny embossed lettering I can see in your picture that says " High Poinrt Products" second line "Multi use balancer"..

Thanks AMA amd Cafeen, Hey Pylon never thought about using on a slant now ain.t that interesting.

Now that Mystery of the Day is done what's next?:cool:

John

John,
I never thought of it either. The instructions that came with mine showed how to do it. If you look at your photo they are both tall, and the photo AMA posted they are both short. If you go 1 of each, the top wheels line up with the bottom of the other wheels. Then you hang large props over the edge of your bench. Works great.

srthstrying please don,t do that at least give it to someone who will utilize it. While not my favorite as I have noted they can be very functional indeed.

In my opinion the major difference between the conventional types and the magnetic is simply the magnetic is so much more friction free. This tends to show up side to side imbalances far more than the conventional types as opposed to the tip to tip imbalances. Since sanding and removing material from a hub side is really a no/no there is not much we can do for side to side problems. This means that a decision to quite a little earlier in tip to tip adjustment needs to be made.

Try just checking the balance with the prop vertical sometimes and this side to side becomes more apparent with the wheel types 'in my opinion' this is not as apparent.

It could be argued that the magnetic type is superior to the wheel types but I wont:)

The bottom line is the magnetic is more tedious to use simply because it requires more time as the it requires that the prop needs to come to a complete stop each check and recheck and it requires some decision as to what is actually occurring is the imbalance side to side, tip to tip or even more common a combination of the two.

John

;) that was a Robot account making a spam posting, John. :)

Ya thanks Jim, I kinda noticed that right after posted that this AM seems like it spammed a bunch of threads. Oh well provided an opportunity stand up a little for the magnetic even if it takes a little more patience to be successful with. I was on the run to get on out to the field this morning so I could maiden my newest little ship, just a cheap ARF with .35AX's was successful and a kick with two flights:

http://www.rcuniverse.com/forum/atta...mentid=1983021

John