Tachometers

[Andrew Bird]

I want to use a tach to set up my latest engine.

I see quite a wide price range for them and wanted to know peoples experiences.

Am I going to be able to do the job with one from tower hobbies for $15 or do I need to get one that costs $100 from AI for accuracy?

(Or can anyone recommend anything in between!)

[iflyrc3Dstyle]

I use the one from Tower Hobbies myself and it works great in my opinion.

Good luck with your choice.

[Al Lewis]

Hobbico works fine. It doesn't need to be that precise to tune an engine.

[Aerobat]

You can check the accuracy of a tach by ponting one at a light bulb, which actually blinks with the AC current. It should read 3600 RPM, set for a 2-blade.

[zoomer260]

	Quote: Originally Posted by Aerobat
	You can check the accuracy of a tach by ponting one at a light bulb, which actually blinks with the AC current. It should read 3600 RPM, set for a 2-blade.

My Hangar Nine also calibrates to fluorescent in the same mannner different reading. It was dead on with both types light. And it cost too much but it does voltage as well. Even has a switch to test a JR Tx through the charge jack.

[Zee]

Make sure you get one that has aoto shut off feature. If it does not shut off when not used it will cost you small fortune in batteries.
Zee

[Andrew Bird]

Thanks for the tip - I think you guys just saved me alot of $$$$.

[RCAddiction]

Most of the tachs are accurate, since the algorithm to count light pulses when the prop blade passes is very rudimentary. The biggest difference I've found is battery consumption, battery type, ability to read the rpm from a safe distance behind the prop, and ability to take a reading with less light. I currently own a TNC and a Magnum.

The TNC tach, sold by Fromeco, is capable of reading from at least 2-3 feet behind the prop on a sunny day and will function in lower light than others. I've owned or tried quite a few (Hobbico, Magnum, Globee, Hangar 9) that require the operator to hold them much closer to the prop than my TNC. The TNC also has auto-shut off and takes a standard 9V battery. Avoid any that take button cells, which don't typically last very long and are surprisingly expensive to replace.

[LawnJockey]

	Quote: Originally Posted by RCAddiction
	Most of the tachs are accurate, since the algorithm to count light pulses when the prop blade passes is very rudimentary. The biggest difference I've found is battery consumption, battery type, ability to read the rpm from a safe distance behind the prop, and ability to take a reading with less light. I currently own a TNC and a Magnum. The TNC tach, sold by Fromeco, is capable of reading from at least 2-3 feet behind the prop on a sunny day and will function in lower light than others. I've owned or tried quite a few (Hobbico, Magnum, Globee, Hangar 9) that require the operator to hold them much closer to the prop than my TNC. The TNC also has auto-shut off and takes a standard 9V battery. Avoid any that take button cells, which don't typically last very long and are surprisingly expensive to replace.

Another vote for Fromeco TNC Tach. I own one and love it.

LJ

[Zeeb]

	Quote: Originally Posted by RCAddiction
	Most of the tachs are accurate, since the algorithm to count light pulses when the prop blade passes is very rudimentary. The biggest difference I've found is battery consumption, battery type, ability to read the rpm from a safe distance behind the prop, and ability to take a reading with less light. I currently own a TNC and a Magnum. The TNC tach, sold by Fromeco, is capable of reading from at least 2-3 feet behind the prop on a sunny day and will function in lower light than others. I've owned or tried quite a few (Hobbico, Magnum, Globee, Hangar 9) that require the operator to hold them much closer to the prop than my TNC. The TNC also has auto-shut off and takes a standard 9V battery. Avoid any that take button cells, which don't typically last very long and are surprisingly expensive to replace.

Another vote for the TNC tach...

I've used less expensive tachs including some of those already mentioned and when running the test with the fluorescent light source they did read pretty close to each other. But in actual use I found some significant differences in the RPM readings between tachs. Now that isn't really an issue if you're just using them to check peak RPM or keep track of changes in performance, but where and how they work is another story.

As mentioned, I found the TNC works in a broader range of lighting situtations resulting from time of day, shadows, or whatever and it does function a lot further away from the prop which is not only handy, but a safety feature.

The auto off feature is something I think you should look for and the TNC has a button you have to hold down all the time since Fromeco took over manufacturing them to accomplish that. That is the only thing I don't particularly care for with the tach, I'd much prefer a standard on/off switch with an auto shut off feature in the software. Even some of the less expensive tachs have that ability and I'm not sure why Fromeco can't/won't adopt that change. Leaving it on and running the batteries dead was the only complaint I ever saw about the older TNC's before Fromeco got the manufacturing rights to the tach.

[ds1rc]

Need button cells for your tac. best price in the US http://www.allelectronics.com/

[Andrew Bird]

What a great site