Prop balancing

[nels]

I’d like to get the prop on my 201 dynamically balanced. What should this cost, how much time will it take and what should the shop have available in order to do a near perfect job? Any suggestions for a shop within a reasonable flight from the Cincinnati area? 

[carusoam]

It’s pretty low cost, high reward, doesn’t take much time...

Finding a guy nearby is helpful...

we have a prop guy around here... @Cody Stallings He is really helpful for these easy questions...

Cody is even more helpful when the questions get harder... 

There is a YouTube video of a popular aviation guy using a lended dynamic balancing system to make the video...  I saw it around here somewhere... it is one part tool, and one part experience...

Best regards,

-a-

[Cody Stallings]

I can’t say what another shop would charge obviously, just what I charge.

$300 is the cost.

Just having a Propeller Balancer is all you really need equipment wise to handle the job.

Time: 1 to 1.5hrs

 

The one thing you wanna really be looking for is the Techs experience Level or If he’s had any type of formal training(How many props does he balance annually).

An individual that is green around the collar can create a lot of unwanted cost for you down the road if things aren’t done properly.

 

[RobertGary1]

I did it once and didn’t find it worth it. May be more beneficial to the older Mooney’s without the balanced crank

 

-Robert 

[carusoam]

The nice part about about balancing a prop... you get a before and after reading measured in IPS(?)...

when your prop is really old and has been filed a few times... measuring/balancing can really make sense...

If we are hoping for a feelable difference... I don’t have that kind of sensitivity...  

Parts of the airframe will be more sensitive than my seat of the pants...

PP thoughts only... not a mechanic.

Best regards,

-a-

[Hank]

My 3-blade Hartzell was balanced by the previous owner at install. Last year at annual, just because it had been so long (2003?), we checked it. The equipment isn't complicated, but someone needs to know how to hook it up and the procedure for running the engine at variois RPMs. Came back at .01 ips, so we called it good.  Not bad for 12 years and 800+ on the tach.

[jwilcoxon78]

Just had mine done for around $300.  Well worth it. 

 

[Culver LFA]

1 hour ago, jwilcoxon78 said:

Just had mine done for around $300.  Well worth it. 

 

Who did the prop balancing for you?  I'm planning on having it done and was hoping for someone fairly local

[DXB]

This new prop balancing tool looks super accurate and somewhat idiot proof. I'd favor a shop if I knew there was one nearby that had one.

 

[jwilcoxon78]

4 hours ago, Culver LFA said:

Who did the prop balancing for you?  I'm planning on having it done and was hoping for someone fairly local

I used Sensenich in Gainesville, GA.  They got mine down to .07 IPS.  I like that they're actually a prop shop so they've got good working knowledge of balance.  Mine was asking for a lot of weight so they so that there was a bit of static weight on it that could be removed.  Did that and then just had to add a slight amount of counterweight to get it dialed in.  I like that approach instead of just slapping on the weight it asked for and moving on. 

 

[Shadrach]

13 hours ago, RobertGary1 said:

I did it once and didn’t find it worth it. May be more beneficial to the older Mooney’s without the balanced crank

 

-Robert 

 It’s funny you mention this. I had breakfast with a fellow Mooneyspacer        (@John Pleisse) this morning after viewing his new to him 66 M20E. We were talking about power settings for approaches.  He said was surprised how much smoother the A1A was over the counterbalanced engine in his M20J.  I would’ve thought otherwise.

[johncuyle]

I had my prop balance checked based on a recommendation from my shop at annual.  ("I don't like the way your baffling is accumulating cracks.  I suspect there's more vibration than there ought to be.  You should have your prop balanced.")  Local prop guy tried to balance, looked at the numbers and told me they were bad enough that he didn't feel comfortable whacking weight on it and I should really take it to the local dedicated prop shop and have them statically balance it.  Charged me hardly anything for his time.  I took it to the local prop shop (Propellers NW) and they took a look at it and informed me they couldn't get it to balance either, needed to look at it closer and made sure I was all in on pulling the prop and statically balancing if necessary.  A few days later they called me back and informed me they had discovered whoever had last installed the prop (before my time as owner, no idea who, when, or how long ago) hadn't torqued it down properly and I was lucky it hadn't separated. (EEEP!  I'd been flying it like that for 120 hours.)  They checked all the studs, inspected the flange for damage, mic'd the holes, told me that my regular shop should double check it against Continental's specs, statically balanced it and then dynamically balanced it to something reasonable (0.1 IPS or a little less.)  It's since been through annual and had a second flange/crank inspection and been signed off as airworthy.  Whole thing cost me a few weeks' downtime, a couple long drives, and about $800.  The funny part is that even spectacularly out of balance I never really suspected anything was THAT wrong since it still felt smoother than the J models I'd flown.  Now?  Sewing machine.  Baffles will probably last a lot longer.  Mostly I'm glad I listened to my mechanic and it got addressed before I got dead.  May your balance be less eventful than mine.

[nels]

I see plenty of prop balance videos on YouTube but they all seem to be for fixed speed propellers. Can the balance change when you go from flat to coarse pitch? How would you get the prop to turn at 2500 rpm cruise using a coarse pitch while the plane is stationary? Maybe it will crank to that rpm in coarse as I’ve never tried it? I mention this  as the balance measuring devices measure imbalalamce at cruise rpm.

Edited April 27, 2019 by nels

[Ned Gravel]

I had my E model's prop balanced about five years ago, before I had to buy a new prop and stop the required 100 inspection because of the old hub.  The guy did it in front of me and it took 45 minutes or so.  Makes no difference about the pitch of the blades - only the speed of their rotation.  The prop hummed along beautifully with nary a vibration at all governor settings before I had to buy the newer hub and blades.

[carusoam]

4 hours ago, nels said:

I see plenty of prop balance videos on YouTube but they all seem to be for fixed speed propellers. Can the balance change when you go from flat to coarse pitch? How would you get the prop to turn at 2500 rpm cruise using a coarse pitch while the plane is stationary? Maybe it will crank to that rpm in coarse as I’ve never tried it? I mention this  as the balance measuring devices measure imbalalamce at cruise rpm.

Sure...

You can expect many things to change... that’s why you balance it at cruise rpm...

Fortunately, balancing at one rpm setting, improves most the others as well. It can’t perfect them all.

There is also some aero challenges going on at the same time.  The run is done static... but, the biggest part of the dynamic balancing is weight related... there is probably restrictions on doing a good job, requires wind to be less than a certain limit... or lining up with the wind will be important...

 

Balancing on the ground takes some care...  Fortunately the data gets collected pretty quickly...

Its amazing how all the rotating parts involved balance out so well...

 

Extra thanks to the folks sharing their hard to balance challenges...  My old M20C suffered a broken engine mount.  It’s prop had years of service being hand filed by a mechanic... it had one big dent in one blade once in its life...

I can now picture how it should have been taken care of back then... Go MS!

Best regards,

-a-

[Davidv]

I’m supposed to get the prop balanced on my Bravo tomorrow (I’m going to do 30/24).  Just so I have a frame of reference, can anyone educate me on the ranges for good, normal, and bad IPS numbers in the aircraft? Mine is a ‘92 TLS and I’m interested to see the before and after.  

I’m sure my mechanic will tell me tomorrow, but I just wanted to know out of curiosity. 

 

Thanks

[nels]

1 hour ago, Davidv said:

I’m supposed to get the prop balanced on my Bravo tomorrow (I’m going to do 30/24).  Just so I have a frame of reference, can anyone educate me on the ranges for good, normal, and bad IPS numbers in the aircraft? Mine is a ‘92 TLS and I’m interested to see the before and after.  

I’m sure my mechanic will tell me tomorrow, but I just wanted to know out of curiosity. 

 

Thanks

I think .07 ips is acceptiple and probably will be where the guy will call it quits.. how much do they want to balance?

[jaylw314]

10 minutes ago, nels said:

I think .07 ips is acceptiple and probably will be where the guy will call it quits.. how much do they want to balance?

My old McCauley we started at 0.15 and got it down to 0.03 after four runs.  That took 1.5 hours or so

My new Hartzell started at 0.04 and we did one more run to get 0.02.  That took 20 minutes.

The flat fee was $325.  Oh well 

[Hank]

2 hours ago, Davidv said:

I’m supposed to get the prop balanced on my Bravo tomorrow (I’m going to do 30/24).  Just so I have a frame of reference, can anyone educate me on the ranges for good, normal, and bad IPS numbers in the aircraft? Mine is a ‘92 TLS and I’m interested to see the before and after.  

Just see what he can do, and when it changes very little between runs, then stop. I'd target .05 or less, my 3-blade Hartzell was still at .01 when we checked it in 2018 [installed and balanced in 2003]. If no prop work is done [no nicks, no dressing, no filing, etc.], it shouldn't change.

[Davidv]

Thanks everyone for the responses. @nels he said it would be 2-3 hours roughly but as @jaylw314 points out, it could depend on how good (or bad) the IPS and vibration is.

[Davidv]

Just an update on this for those interested.  The initial IPS measurement was .04 so we decided not to take any action.  However, I told him that my vibration still felt a little too much.  When he initially uncowled the engine we noticed that the baffling on the left side was turned down rather than up (where it should be next to the cylinder heads).  As some people previously mentioned, I was shocked at the difference this made.  Even though we didn’t do any balancing, there was a noticeable difference in vibration on my flight home and flights since last week. My cylinder temps are also better as well.

[TheTurtle]

my guy was 250.  Got it to .07 (.7)??

Prop was overhauled about 10 hours ago and my IA said to get it balanced after it "sets".  It was originally just under the high limit.

He had a machine like a seismic  thing you see in the movies with a pen that bounces around on a sheet marking the ips.  After he was done he gave me the sheet to put in the prop log.  He just put one weight on my prop hub.  took him an hour max.  that includes removing the spinner and resafety wiring the hub.

Edited May 6, 2019 by TheTurtle

[Skates97]

2 hours ago, TheTurtle said:

my guy was 250.  Got it to .07 (.7)??

Prop was overhauled about 10 hours ago and my IA said to get it balanced after it "sets".  It was originally just under the high limit.

He had a machine like a seismic  thing you see in the movies with a pen that bounces around on a sheet marking the ips.  After he was done he gave me the sheet to put in the prop log.  He just put one weight on my prop hub.  took him an hour max.  that includes removing the spinner and resafety wiring the hub.

Where did you have it done? 

[TheTurtle]

On 5/5/2019 at 8:53 PM, Skates97 said:

Where did you have it done? 

at my tiedown.  SNA

[Shadrach]

10 hours ago, Hyett6420 said:

A preflight trick/check i learnt from @Oldguy when i flew with him down to the summit a few years back.... Shine a torch into the cowling, look at the baffles and make sure they are all facing forwards and tightly pressed up,against the cowling.  Ive had mine blow back before and declared an "urgency" to London to get on the ground as I watched the oil temp climb too far into the green.  Thise baffles make a HUGE difference if not set right. C

This is a post mx pet peeve of mine. Propery installed baffle seals do not “blow back”, the are often not dressed forward by the person installing the top cowl. I can’t tell you how any times I’ve had to reach in and roll them forward with my fingers (easy with the old guppy mouth cowl) after the plane was in the shop or the cowl removed by one of my partners. Rear CHTs see a significant bump if the seal is opening under air pressure.