Propeller Track, Balance, and Vibration Limit

Track and balance are DIFFERENT faults with different fixes, and both produce vibration -- which is why checking track first is what stops a technician chasing a tracking fault with weight. Out of track means the blades are not sweeping the same plane, so each blade meets the air differently and the propeller generates a once-per-revolution AERODYNAMIC imbalance that no amount of weight corrects. Out of balance means the mass distribution is uneven, and that is what weight corrects. Reporting the track verdict before the balance arithmetic is deliberate: a balance run on an out-of-track propeller chases a moving target and can end with weight added that makes the aerodynamic problem no better and the mass distribution worse. The balance itself is the trial-weight vector method. A trial weight is placed at a known angle, the run repeated, and the EFFECT vector -- the difference between the two readings, not the second reading -- tells you what the propeller does per gram and at what phase lag. The correction is then the trial weight scaled by the ratio of the original vibration to that effect, rotated so its effect opposes the original. If the trial weight produces no change in the vector it has told you nothing, and that case is reported rather than divided by. A static bench check on knife edges is necessary but not sufficient: it finds a gross mass asymmetry and cannot find a dynamic couple, and a propeller that balances statically can still shake an engine. This computes a single-plane correction from ENTERED readings taken with a calibrated analyser; it does not measure anything, validate the phase reference or the tachometer pickup, address two-plane balancing, distinguish propeller imbalance from an engine or mount problem producing vibration at the same frequency, or set the limits. The propeller and airframe manufacturers' limits, the analyser's own procedure, and a certificated mechanic govern.

track is compared against the manufacturer's limit; for balance the EFFECT vector is the trial reading minus the original, and the correction is the trial weight scaled by the ratio of the original to that effect, rotated so its effect opposes the original.

The track check against the manufacturer's limit and the single-plane trial-weight vector method. Readings are ENTERED from a calibrated analyser. It does not measure anything, validate the phase reference or tachometer pickup, address two-plane balancing, distinguish propeller imbalance from an engine or mount problem at the same frequency, or set the limits.

One vector subtraction and one scaling.

Estimate. AHJ and licensed professional govern.

Field names used by the API: track_in, track_limit_in, initial_ips, initial_phase_deg, trial_weight_g, trial_phase_deg, result_ips, result_phase_deg, target_ips, track_margin_in, effect_ips, effect_phase_deg, correction_weight_g, correction_phase_deg

• Track first a balance run on an out-of-track propeller chases a moving targetthe propeller manufacturer's limit
• Single plane a dynamic couple needs two-plane balancingthe analyser's own procedure
• Readings are entered the phase reference and tachometer pickup are not validated herea certificated mechanic