Download Magneto Test Bench

Magneto Test Bench
Thompson Aircraft Maintenance
San Luis Obispo, California
30 March 2005
Magneto Test Bench
Magnetos 101
• Magnetos are old technology
• On cars were replaced by coil ignition
system
• Simple system
– Engine driven
– Magnetos keep generating spark even if
lose electrical system
– Trouble-free
30 March 2005
Magneto Test Bench
Aircraft Engines 101
•
•
•
•
Air cooled
4 or 6 cylinder
“Boxer” engine
Doubly-redundant
magneto ignition
system
– Each magneto
generates spark for
all four cylinders
30 March 2005
Magneto Test Bench
Magneto Installations
Magnetos on back side of
engine. Notice four spark
leads coming from magneto.
30 March 2005
Dual mags on six-cylinder twin
engine plane.
Magneto Test Bench
Magnetos Up Close
Engine side of mag shows
gear drive. Different make
mags have different drives.
30 March 2005
Lead side of mag shows
spark lead connections.
Magneto Test Bench
Manually Testing Mags
Current test procedure is manual and subjective.
Spin mag drive and look at spark. Qualitatively
assess strength of spark.
Spark test leads for
magneto tester
30 March 2005
Spin drive gear manually
And observe spark strength
Magneto Test Bench
Magneto Test Bench
• Want to make testing more quantitative
• Want to drive mag with a motor at various speeds
(0-2800 RPM)
• Want to be able to measure voltage at spark leads
• Want to be able to accommodate mags of different
makes (Bendix, Slick, etc.)
• Want to be able to accommodate 4- and 6-cylinder
engines
• Want to be able to drive different mags with motor
• Want to be able to observe spark also
30 March 2005
Magneto Test Bench
Magneto Test Bench
• Make test bench out of off-the-shelf
components
– 80-20 structural pieces, e.g.
– Standard motor and measuring equipment
from McMaster-Carr, e.g.
– Inexpensive
30 March 2005
Magneto Test Bench
Contact Information
Cody Thompson, A&P, IA, 471-1119
30 March 2005
Magneto Test Bench