pierre smith
Well Known Member
I just had my -6A prop balanced recently and it made a big difference, so I decided to do my Air Tractor as well. I flew to Gainesville, Ga. on Wednesday and was met by the Sensenich Propeller service guys (no relationship to Sensenich propellers, BTW), and learned quite a bit at their shop.
Long story short: the difference is remarkable and it's incredibly smooth...then again, turbines are smooth, but for your bearings sake and the sake of your avionics, here are some very good reasons to balance your RV's as well:
What level of propeller vibration is acceptable?
Here are some vibration levels that are possible, and what to expect at the different levels.
DANGER------------------1.25 Inches per second. This is very rough and dangerous to
the aircraft and components. The propeller should be removed
and a static balance performed.
VERY ROUGH----------1.00 Inches per second. Propeller can be dynamically balanced;
a large amount of weight will be required, not the best solution.
Ideally, the propeller should be removed and a static balance
performed. For any level above a .8 ips you should consider a static balance.
ROUGH--------------------.5 Inches per second. Propeller balancing will greatly enhance the ride comfort.
Long term operation at this level could cause premature wear.
SLIGHTLY ROUGH----.25 inches per second. Again, a balance will enhance ride comfort and reduce
possible premature wear.
FAIR-------------------------.15 Inches per second. The maximum vibration level after a dynamic balance.
GOOD----------------------.07 Inches per second. Vibrations at this level and below is considered to be
the area where the pilot and passengers will not feel any rotational imbalance.
This level and below should be the balancing goal.
A static balance is done at a propeller repair station. This is where the propeller is placed on presision rollers or knife blades and trim weights are added until the propeller will not move when put in any position, i.e. vertical, horizontal or 45 degrees, etc. This is the starting point of a good balance.
Some simple facts
Propeller balancing does not mask engine problems
Vibration causes cracks in sheetmetal over time
Vibration can cause expensive damage to avionics and instruments
Pilots will get accustomed to almost any vibration level over time
Most pilots believe their propellers are smooth
9 out of 10 propellers needs a balance
Vibration increases pilot fatigue
Vibration can cause passenger concerns
31 grams of static weight at 6 inches from the propeller centerline becomes a 61 pound rotational load on the front engine bearing at 2300 rpm. If it takes 31 grams of weight to balance the propeller, there was a 61 pound rotational imbalance
Long story short: the difference is remarkable and it's incredibly smooth...then again, turbines are smooth, but for your bearings sake and the sake of your avionics, here are some very good reasons to balance your RV's as well:
What level of propeller vibration is acceptable?
Here are some vibration levels that are possible, and what to expect at the different levels.
DANGER------------------1.25 Inches per second. This is very rough and dangerous to
the aircraft and components. The propeller should be removed
and a static balance performed.
VERY ROUGH----------1.00 Inches per second. Propeller can be dynamically balanced;
a large amount of weight will be required, not the best solution.
Ideally, the propeller should be removed and a static balance
performed. For any level above a .8 ips you should consider a static balance.
ROUGH--------------------.5 Inches per second. Propeller balancing will greatly enhance the ride comfort.
Long term operation at this level could cause premature wear.
SLIGHTLY ROUGH----.25 inches per second. Again, a balance will enhance ride comfort and reduce
possible premature wear.
FAIR-------------------------.15 Inches per second. The maximum vibration level after a dynamic balance.
GOOD----------------------.07 Inches per second. Vibrations at this level and below is considered to be
the area where the pilot and passengers will not feel any rotational imbalance.
This level and below should be the balancing goal.
A static balance is done at a propeller repair station. This is where the propeller is placed on presision rollers or knife blades and trim weights are added until the propeller will not move when put in any position, i.e. vertical, horizontal or 45 degrees, etc. This is the starting point of a good balance.
Some simple facts
Propeller balancing does not mask engine problems
Vibration causes cracks in sheetmetal over time
Vibration can cause expensive damage to avionics and instruments
Pilots will get accustomed to almost any vibration level over time
Most pilots believe their propellers are smooth
9 out of 10 propellers needs a balance
Vibration increases pilot fatigue
Vibration can cause passenger concerns
31 grams of static weight at 6 inches from the propeller centerline becomes a 61 pound rotational load on the front engine bearing at 2300 rpm. If it takes 31 grams of weight to balance the propeller, there was a 61 pound rotational imbalance
