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  #11  
Old 04-13-2019, 01:01 PM
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Walt Walt is online now
 
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Location: Dallas/Ft Worth, TX
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The below chart is generally considered the "standard" values for balancing.
My goal is 0.050 IPS or better when balancing, .010 is very seldom obtainable on professional balancing equipment.
I've done balance checks after Dynavib balances and other "hobby" balancers and my numbers are always higher (I can't even get .01x on my own aircraft after multiple attempts). I have had a few over the years that got into the .01x range but after hundreds of balance jobs I can assure you that .01x is generally impossible to achieve (notice my equip goes out 3 places while most only go 2 places)

What some of the manufactures say:

Unless otherwise specified by the engine or airframe manufacturer, Hartzell
recommends that the propeller be dynamically balanced to a reading of 0.2 IPS,
or less.

Most dynamic balance equipment manufacturers specify 0.15 - 0.2 ips as being an
acceptable level. McCauley Propeller Systems agrees that 0.15 - 0.2 is an acceptable
level, but our experience has shown that 0.07 ips or lower is noticeably smoother.

DANGER — 1.25 Inches Per Second (IPS) Peak Amplitude. The propeller should be removed and a static balance performed.

VERY ROUGH — 1.00 Inches Per Second (IPS) Peak Amplitude. Propeller can be dynamically balanced; however a large amount of weight will be required. A propeller static balance is recommended. Operation at this vibration level could cause damage.

ROUGH --- 0.50 Inches Per Second (IPS) Peak Amplitude. Propeller definitely requires dynamic balance. Long term operation at this vibration level could cause excessive wear.

SLIGHTLY ROUGH -- 0.25 Inches Per Second (IPS) Peak Amplitude. Dynamic balance will improve passenger comfort.

FAIR---- 0.15 Inches Per Second (IPS) Peak Amplitude. This is the maximum acceptable vibration level after dynamic balancing.

GOOD ---- 0.07 Inches Per Second (IPS) Peak Amplitude. Vibration levels below 0.07 will not be detectable by pilots or passengers.
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Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154

Last edited by Walt : 04-13-2019 at 01:31 PM.
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  #12  
Old 04-13-2019, 01:15 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
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Quote:
Originally Posted by Walt View Post
My goal is 0.05 IPS or better when balancing, .01 is seldom obtainable on professional balancing equipment.
I agree. That is why I said a pro should be able to get close to .01.
I regularly get final values of .02 or .03 (though not meaning to imply I am a pro.... I only do 3 or 4 per year)
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RV-6A (aka "Junkyard Special ")
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  #13  
Old 04-13-2019, 04:13 PM
jask jask is offline
 
Join Date: Feb 2018
Location: Ramona, CA
Posts: 119
Default Balancer

I use the classic dynavibe and I take 5 averages before I process the numbers eliminating the high and low ips and outside angles. I process the remaining average and that works well for me.
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(I am not in the business of prop balancing, just as a courtesy to meet other owners.)
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  #14  
Old 04-13-2019, 06:16 PM
Dave12 Dave12 is offline
 
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Location: Elkton, Md.
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Walt, what brand do you use? 2 accelerometers 1 front, 1 rear?
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  #15  
Old 04-13-2019, 06:19 PM
Dave12 Dave12 is offline
 
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Location: Elkton, Md.
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Quote:
Originally Posted by rvbuilder2002 View Post
Hopefully you mean .01
.1 is not horribly bad but when paying a professional do it, they should be able to get it very close to .01.


BTW, the acceleration value that is considered noticeable is .07 or higher (not .7)
Actually, by the time the weight was mounted on the spinner backing plate it was .02.
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N588DF RV12 #336 Sold
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  #16  
Old 04-13-2019, 06:31 PM
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Walt Walt is online now
 
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Location: Dallas/Ft Worth, TX
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Quote:
Originally Posted by Dave12 View Post
Walt, what brand do you use? 2 accelerometers 1 front, 1 rear?
MicroVib II, I only use the front accel to balance the prop, if you want to mount a rear you can but nothing you can do to really change that so it pretty much a waste of time unless you have a internal engine vibration you are trying to diagnose.
__________________
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
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