I recently purchased a Hangar 9 digital voltmeter/tachometer......I started my os .46 and placed the tach two inches in front of the spinning prop, with the prop selection set at 2, for two blades.........no reading at all; but if I fan my hand in front of the tach it starts to register rpms..........if I place it in front of the house fan, it registers rpms, then in front of the spinning prop and nothing happens, zero reading........any suggestions would be appreciated.











Flying is like breathing.......Everybody should do it.

Where is the plane located when you try to take a reading? If it is in a garage that may explain it. The tach needs to see a light source through the prop as it spins and it counts the number of ties it sees the light. Even out in the open on a sunny day the angle of the sun may prevent the tach from being able to get a good reading. If you have to run the engine in a garage placing a lamp in front of the prop and then taking a reading from behind the prop should work. Hope this helps. [8D]

Fastsky is right. The prop needs to reflect light for the tach to read it.

Fatsky and Bruce are right on the money.

Ken

Be aware that under any AC light (flourescent or incandescent) you can get mixed up readings. especially with flourescent. That is because the light is pulsing on/off 120 times per second. point the tachometer at a flourescent light and it should read 3600 when set to 2-blade prop. When I'm working with the tach indoors (like with an electric motor), I use a car headlight to provide the light through the prop.

thanks guys, I am on my way to the garage to try it again, and I will place a lamp behind the model........I know it will work now, you guys are great.














Flying is like breathing.......Everybody should do it.

If that don't work, need to get another engine!

Is the engine running?

a "lamp" might not work... sunlight or general outdoor ambient light is the best


also, for safety sake, I might suggest you take your readings from behind the prop instead of in front

Absolutely, you should always work from behind the spinning prop. If the prop should come off, or the plane slip forward, or any number of other things you could be seriously injured by the spinning prop.

Ken

It worked, just like all of you said it would. Thanks again.













Flyin' is like breathing.......everybody should do it.