This is a recent thread from the Lancair group. I hadn’t seen this before. I’ve got a IO550N with a single Light Speed III and Hartzell 3 blade metal prop..
From MT
About 18 months ago, 110 flight hours ago, I removed my mags and installed an electronic ignition. MTs conclusion is that the new ignition excited dynamic modes that beat up the prop. In are conversations, they told me that others have experienced the same damage, some after flying for 20 years with their props, like me, and after installing an electronic ignition. Some completely destroyed their props.
This is from Hartzell Manual 193 for experimentals:
D. Electronic Ignition Compatibility
The combinations listed in Tables 1 and 2 in the Vibration Compatibility Tables
chapter of this manual are considered acceptable only with the ignition systems
noted. Hartzell is actively testing to investigate the effect that electronic ignition
systems have on propeller vibration. Preliminary data has shown that electronic
ignition systems can produce increased vibrational loads for the propeller. The
specific effects of adding electronic ignition can vary depending on the exact
propeller/engine/ignition system combination.
Electronic ignition systems operating at fixed timing also have the capability to
increase propeller stresses. Vibration testing has shown that changing from magneto
ignition with standard timing setting to fixed timing electronic ignition at the same
timing setting can make a significant impact on propeller loads.
At this time, Hartzell can only endorse use with the exact ignition systems listed, in
conjunction with the exact propeller/engine combination listed. Electronic ignition
systems in Tables 1 and 2 in the Vibration Compatibility Tables chapter of this
manual have been verified to be compatible when tested using the manufacturer's
instructions, setup procedures, and preset timing profiles. Changing the timing profile
from the manufacturer's settings or other modifications to the setup can change the
propeller vibratory loads and is therefore not covered by the compatibility finding.
Use of engines with unverified electronic ignition systems is done at your
own risk.
From MT
About 18 months ago, 110 flight hours ago, I removed my mags and installed an electronic ignition. MTs conclusion is that the new ignition excited dynamic modes that beat up the prop. In are conversations, they told me that others have experienced the same damage, some after flying for 20 years with their props, like me, and after installing an electronic ignition. Some completely destroyed their props.
This is from Hartzell Manual 193 for experimentals:
D. Electronic Ignition Compatibility
The combinations listed in Tables 1 and 2 in the Vibration Compatibility Tables
chapter of this manual are considered acceptable only with the ignition systems
noted. Hartzell is actively testing to investigate the effect that electronic ignition
systems have on propeller vibration. Preliminary data has shown that electronic
ignition systems can produce increased vibrational loads for the propeller. The
specific effects of adding electronic ignition can vary depending on the exact
propeller/engine/ignition system combination.
Electronic ignition systems operating at fixed timing also have the capability to
increase propeller stresses. Vibration testing has shown that changing from magneto
ignition with standard timing setting to fixed timing electronic ignition at the same
timing setting can make a significant impact on propeller loads.
At this time, Hartzell can only endorse use with the exact ignition systems listed, in
conjunction with the exact propeller/engine combination listed. Electronic ignition
systems in Tables 1 and 2 in the Vibration Compatibility Tables chapter of this
manual have been verified to be compatible when tested using the manufacturer's
instructions, setup procedures, and preset timing profiles. Changing the timing profile
from the manufacturer's settings or other modifications to the setup can change the
propeller vibratory loads and is therefore not covered by the compatibility finding.
Use of engines with unverified electronic ignition systems is done at your
own risk.
