Which tachometer should I purchase?

[frank mccune]

      What tach should I purchase to be used on my model airplanes?

                                                                                                            Tia,

                                                                                                            Frank

[Larry Renger]

My Caltech EE graduate brother built me a tach checker. It works up to 60k!

Except for two tacos, they all are accurate within acceptable limits. The exceptions are an ancient Heath unit, and surprisingly the expensive TMJ TACH.

The main criteria is how well the tach can read the prop.

I have a  Globee unit. For great readings I added a snoot painted black inside and then added a lens focused at infinity onto the sensor. It can read a prop from a foot away.

[Larry Renger]

My Caltech EE graduate brother built me a tach checker. It works up to 60k!

Except for two tacos (should be tachs, but who can argue with spellcheck?), they all are accurate within acceptable limits. The exceptions are an ancient Heath unit, and surprisingly the expensive TMJ TACH.

The main criteria is how well the tach can read the prop.

I have a  Globee unit. For great readings I added a snoot painted black inside and then added a lens focused at infinity onto the sensor. It can read a prop from a foot away.

[Brett Buck]

      What tach should I purchase to be used on my model airplanes?

    Of the currently-available, I would get the Fromeco and make the modifications that David made to it at my suggestion. It shows out-of-stock, so you might have to check and see.

   Despite Larry's oft-stated comments on the accuracy, the cheap units are not very accurate in real-life conditions, although they are close enough when you attempt to 'calibrate' them. Put them side-to-side on a real prop and they will not likely read the same, many units being thousands of RPM off from each other. The Fromeco has some changes we suggested to make it more reliable, but really needs to have the sensor bare in the front with a baffle, rather than the "transparent to IR" window or the shiny tube baffle. David's original unit with the modification shown below works as well as the TNC.

    Brett

[Norm Furutani]

Has anyone checked out the tach apps available for your phone? An audio tach would be very cool!

[Steve Helmick]

Get this one.

https://www.towerhobbies.com/cgi-bin/wti0001p?I=LXHVJR&P=ML

That's the one I use and recommend. I did make a hood from a piece of Delrin rod that pushed on over the lens tube. Idea was to shield the lens from sunlight coming from odd directions. I can't say that I'm 100% sure it helps, but it certainly doesn't seem to hurt anything.  Steve

[proparc]

Get this one.

https://www.towerhobbies.com/cgi-bin/wti0001p?I=LXHVJR&P=ML

That is the one I have. Don't know if is accurate or not because I have nothing to check it with. That said, I have a run A LOT OF motors with that thing. From Saito 40's to Moki 150's and too many to mention in between. Yes, including the much vaunted Enya 80X lol. Yes, it is as powerful as they say. It is like a Honda VTEC motor. "Hey this ain't all powerful, let me open the throttle-Holy@#$%^ 

[RandySmith]

Get this one.

https://www.towerhobbies.com/cgi-bin/wti0001p?I=LXHVJR&P=ML

Motorman  is  correct, that little  tach  works  really well, much better    than  any other  ones of the cheaper versions out there

Randy

[Jim Hoffman]

I purchased a new Fromeca tach in 2017 and found it unusable and eventually returned it for a refund.

The tach looked the same as the old Fromeca tachs  Unfortunately an electronic design change was made that caused the reading to jump up and down very rapidly at a rate greater than 1 Hz. (1 per second).  The range was large, +/- several thousand RPM. 

I don’t recall the details two years later, a fellow named Kurt who may have designed the original worked with me in a professional manner but could not remedy my issue.  I even sent it to him to check out.  He said it was working fine and demonstrated that the tach was stable when pointed at an AC light source.   He stated he could not undo the design mod that had occurred.  Perhaps it was a firmware issue.   

We tried numerous techniques on positioning the tach with no success, a variety of airplanes, and the long tube at the lens mod too. 

I have since gotten an earlier Fromeca tach that works fine.