Hello,

I have been racking my head over this since I purchased my "Topflite" Prop Balancer.

Now when I use the balancer as the instructions state, I place the cones so that the narrow ends point towards the hub and eachother (Left Photo). However, the cones touch and do not securely hold the prop in place (not enough clearance between the two).

Ok... Below I have posted three pictures displaying three different combinations of installing the prop on the balancer using the cones provided.

Each combination has a different effect, meaning the prop balances totally different on each setup.

I read somewhere on RCU that props have a "precision" hole (smaller hole I believe) and a "non-precision hole)

In this case, the "precision" hole is on the left in all pictures.

Considering that all results vary greatly, what combination is the correct combination to use?

The photo on the left is the recommended setup. I've experienced the same thing, cones touching and not holding the prop snugly, with some props.

I've never heard of a 'non precision' hole. APC and Master Airscrew have a stepped hole. The center hole is usually 1/4 and the bigger hole is usually 5/16 since these are very common shaft sizes for many popular glow engines.

I do not balance props unless I install one and have a vibration.

i,m also confused haw does the prop balancer work what if the prop is out of balance what do you do[]

I see... I was afraid that the 5/16 hole may not be centered as precisely as the 1/4 inch hole. So I assume they both are centered pretty well.

I experienced what seemed to be severe vibration, on my SIG Kadet Senior, while the engine was running at low RPMs (2500). So I decided to get a prop balancer. The engine (OS .46 LA) is brand new, and has been broken in. I believe that I managed to fine tune it as well. It has a Max RPM of 11,500 and an idle at 2500 - 2750.

I checked over everything such as mount to firewall and engine to mount... they are all snug as a bug.

Unless the vibration I mentioned is normal, than I assumed the prop is out of balance.

The Senior has a large Air Frame, and the covering is wicked resonant. Mabey the vibrations I was seeing was normal?

I intened on having a gentleman at the local club check it out anyhow, but I thought I'd post to get some opinions.

Well, a prop balancer allows you find out if one of your prop blades is heavier than the other. Sometimes the Hub can be heavier as well. To correct this weight variation you can add weight to the lighter side of the prop using different mediums such as spray adheasive, CA, tape or clear cote finish. Some people like to sand the prop blades to remove weight, but that can be adverse and change the airfoil shape of the prop.

A perfectly balanced prop should be able to remain stationary in any orientation.

My brother has a Saito 1.25 that has a vibration at a certain RPM but is very smooth at all other RPM. It's not at idle on his engine, which is 2000 or so, maybe around 2800. He tried balancing the prop, and a different prop, but the vibration at that rpm is always there.

I thought about removing some of the tapered portion of the cones so they do not touch but never bothered to do it.

Yeah, I considered that too. But I am afraid that I would throw the Balancer out of Balance. Seems like it could be too much of a pain.

I very carefully sawed the tips about an 1/8th inch off each cone and have never had a problem with them touching since. put the shaft in an electric drill and lightly sand with 300 grit paper to true out the cones

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I experienced what seemed to be severe vibration, on my SIG Kadet Senior, while the engine was running at low RPMs (2500). So I decided to get a prop balancer. The engine (OS .46 LA) is brand new, and has been broken in. I believe that I managed to fine tune it as well. It has a Max RPM of 11,500 and an idle at 2500 - 2750.

I checked over everything such as mount to firewall and engine to mount... they are all snug as a bug.

Unless the vibration I mentioned is normal, than I assumed the prop is out of balance.

The Senior has a large Air Frame, and the covering is wicked resonant. Mabey the vibrations I was seeing was normal?

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Hi.... I had an OS .46LA a couple years back and it vibrated quite a bit on low rpms also. I read somewhere that is just natural for the LA series. All my AX, FX, FXi OS motors all ran smooth with the same prop as I had on the LA. Still, balancing all props is a good idea regardless!!

Curt

I use my wife’s nail polish on the back of the prop.

If the cones meet before tightening onto the hub you won't be able to rely on the balancer since you cannot be certain the prop is centered. The tip about removing some of the point on one or both cones sounds like a winner to me.

Clay

Stole my Sisters for the same reason!

I think I will use that tip.