Prop Hub Static Balancing?

[supik]

Do you guys do prop hub static balancing before dynamic balancing?

This is how my hub looks like from inside and it's throwing of when the engine is running. Found a bit of grease on both inner sides of the hub; the airplane has about 16hrs TT.

Lyc IO 540
Van's standard prop hub
Hartzell standard 2 blade CS

I'm just wondering whether I shouldn't start with static bal. first. If so, what's the recommended method / procedure?

[agent4573]

The hubs should come statically balanced from the factory, so doing it again probably isn't required. Put a dynamic balancer on it and if it starts at more than 1.0 IPS then it needs a static balance. If it starts under that you can probably balance it out on the plane. Check the installation/owners manual, I thought some grease was normal on brand new props. If that's all grease in the picture though, that seems a bit excessive.

[BoydBirchler]

I think what you are calling a "hub" is generally referred to as being a prop spinner.

Yes, the spinner gets dynamically balanced with the prop in the procedure.

[supik]

Thank you all, yes my bad, it's the spinner.

Here is another pic with the grease visible. More or less the same amount can be found on the opposite side of the inner side of the spinner (not visible in picture).

There is lots of unevenly distributed epoxy where the spinner was separated from the form. (this is what you saw in the 1st picture)

I wanted to verify the static balance of the spinner but found videos for static balancing RC model spinners only.. Haven't found a good resource for static balancing real aircraft spinners.

[supik]

picture with grease:

[rv8ch]

Hi Igor, this looks very much like what my spinner looked like as well. I sanded it a little bit to make it smoother, but I didn't bother trying to balance it. I did a dynamic balance on the prop with the engine running using a dynavibe classic, and lots of instructions on the internet. The company that sells the dynavibe was also happy to answer questions. You probably have someone near you that has one or something similar.

Surprisingly my prop/spinner was very balanced, so it took very little effort to get it down into the "excellent" range.

I didn't get much grease leaking out of my Hartzell, perhaps just a little mist on the windscreen and on the cowl the first few hours of flight time.

There seems to be 3 different types of grease used in our Hartzell props, Aeroshell 5, Aeroshell 6, and Nyco GN3058.

https://hartzellprop.com/top-tips-fo...r-lubrication/

Seems the Nyco is the best - I hope you have that. There are a lot of reports of Aeroshell 6 leaking. Unfortunately to change from 6 to Nyco, you have to essentially do an IRAN on the prop hub.

[Walt]

Originally Posted by agent4573

The hubs should come statically balanced from the factory, so doing it again probably isn't required. Put a dynamic balancer on it and if it starts at more than 1.0 IPS then it needs a static balance. If it starts under that you can probably balance it out on the plane. Check the installation/owners manual, I thought some grease was normal on brand new props. If that's all grease in the picture though, that seems a bit excessive.

When I see a reading of 1.0 IPS it’s time to regroup, usually something drastically out of wack and I won’t attempt a dynamic balance. A “normal” high vib is less than half that.

Balancing the spinner would be a waste of time.

[agent4573]

Originally Posted by Walt

When I see a reading of 1.0 IPS it’s time to regroup, usually something drastically out of wack and I won’t attempt a dynamic balance. A “normal” high vib is less than half that.

Balancing the spinner would be a waste of time.

Agreed, but I've been confronted before about not sticking strictly to manufacture recommendations. Dynavibe doesn't mention redoing the static balance until 1.0.

[Walt]

Originally Posted by agent4573

Agreed, but I've been confronted before about not sticking strictly to manufacture recommendations. Dynavibe doesn't mention redoing the static balance until 1.0.

If an owner wants to confront me on my recommendations, it’s pretty simple for me… put it back together and send him down the road.
I prefer not to put my name in the logbook when I suspect something is wrong. (I’ve done this a number of times, most come back with a new or OH’d prop and thanked me).
I don’t let let the customer dictate what I do, and I don’t have a boss telling me what to do anymore either (except my wife).

[Tankerpilot75]

Originally Posted by Walt

I don’t let let the customer dictate what I do, and I don’t have a boss telling me what to do anymore either (except my wife).

Getting a little cranky? Must be winter!