Confusing readings on hangar 9 tachometer?

[Matt Curtis]

I have the newest version of the hangar 9 tachometer and I get a reading of 287 with my k&b .28 with a 10/4 prop. Bottom numbers are searching with I think 430 and 418? Cannot figure this out? Why does it have all these different readings? I setit for 2 blade prop. I don't remember the older versions working like this. They would just show 1 reading and there was no trying to figure it out.

[Steve Helmick]

This one? https://www.horizonhobby.com/product/micro-digital-tachometer/HAN156.html

These've been around for decades. I made a push-on tube to shade the lens, and it helps, but it's still a bit touchy to light intensity and direction you point it.

What you described is puzzling. A typical stunt-ish engine reading should be something more like 960 for a launch setting. They wouldn't bother with the 10's digits, because the engine will show more variation than that.  Steve

[Colin McRae]

I went thru 3 of these Hangar 9 tachs and all 3 stopped working after a relatively short period of time.

I gave up and am now trying a G.T. Power RC mini tach which is similar to the Hangar 9. After about 6 months now it is working fine and accurate. But longevity, who knows!