Bought a $30 laser tach to check prop RPM and it read 200 higher than the panel gauge

Diana Lee · 2026-10-10T12:05:03.908793+00:00

I picked up a cheap laser tach off Amazon about 3 weeks ago to double check a Cessna 172 at my shop here in Wichita because the owner kept saying the prop felt fast on runup. The laser showed 2,380 while the panel gauge read 2,180, so I had another mechanic shoot it with his old mechanical tach and he got 2,190, which means my $30 toy was the odd one out. Has anyone else run into a cheap tach that reads high, or did I just get a bad unit?

SMM Buzz

Loading…

Bought a $30 laser tach to check prop RPM and it read 200 higher than the panel gauge | Aircraft Mechanics - SMM Buzz