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Trutach II Optical Digital Tachometer

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Part# 10-01021


An inaccurate tachometer can waste performance, fuel and engine life. Mechanical tachometers are notoriously inaccurate and should be checked at each annual and 100 hour inspection or any time aircraft performance is in question. The TruTach II Optical Digital Tachometer measures the true speed of your propeller from inside or outside the aircraft. Just point it at the propeller or rotor blades and TruTach II will directly display the rotational speed with a resolution of 1 RPM. No connection to aircraft systems is required and measurements may be made at any speed setting from 240 to 70000 RPM.

Direct display is available for 2, 3, 4, and 5 blade propellers. Digital Signall Processing assures rock-solid display in single and multi-engine aircraft as well as helicopters. The compact 4-inch instrument weighs just 4 ounces and may be used with fast turning ultra-lights and kit plane propellers. Just turn it on, select the number of propeller blades and point. Automatic shut-off turns the unit off if you forget. The Tru Tach II includes a standard 9 volt battery providing 150 hours of operation.


Great little stand alone device. Seems to work well and the company takes pride in their product. The tachometer was packaged well in the box with a manual that was in English and not translated from another language. The unit is powered by a 9v battery that was included! Nothing else to buy, just put the battery in and go fly.

Black W Verified Purchase


January 21, 2022

Worked great was right on the money with my EIS readout. Set on my dash with a aux. MP for heads up attitude.

Robert G Verified Purchase


January 20, 2022

Does exactly what it’s supposed to do

Gearey A Verified Purchase


January 18, 2022

It works as advertised.

James B Verified Purchase


December 14, 2021

I purchased this to verify the manual tachometer in the plane and to set the ground adjustable prop to get the recommended RPM.

John C Verified Purchase


November 7, 2021

Ordered the TruTach as a back up to my 71yr old mechanical Tach in my Stinson. Super easy to use and took all of a minute to set up. After comparing the two at idle my mechanical read 1000rpm and the TruTach read 1100! At cruise there was a 75 RPM difference as well. The unit sits on my panel right in my line of sight and has no problems reading from that far back. Love the unit. Highly recommend.

Christopher L Verified Purchase


September 28, 2021

very satisfied works perfectly

Lee N Verified Purchase


September 14, 2021

Unit works as advertised. Easy setup and easy to use. I would recommend this to anyone wanting to check their mechanical tachs.

Terry M Verified Purchase


September 2, 2021

It is working well!

May 11, 2021

It works just as advertised, was priced right, delivered very quickly so whats not to like!

Carl K
April 10, 2021


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: What are the panel dimensions for the TruTach II?

The dimensions are 2-1/4" W x 1-7/16 H x 3-3/4" D. This product in not meant to be installed in a panel.

Q: Does the Trutach II Optical Digital Tachometer come with a protective casing or box?

The Trutach II Optical Digital Tachometer is packaged inside of a box.

Q: Do you have to set the Trutach II Optical Digital Tachometer for 2, 3 or4 blades every time you turn it on in a two blade C-172?

No, the Trutach II will store the desired number of blades and start with this input every time.

Q: Does the Trutach II digital instrument remain on for the duration of flight, or is one constantly cycling it prior to altering engine parameters?

The Trutach II is able to monitor changes in RPM and display them in real time. There is no need to turn the instrument off during flight.

Q: Does the TRUTACH II OPTICAL DIGITAL TACHOMETER Part # 10-01021 come calibrated or have the capibilities of being calibrated?

Per Trutach: The only calibration available is to switch from 2-5 prop blades.

Q: Will it work if I put it on the glare shield inside the aircraft?

Yes, the Trutach II is intended to be put on the glare shield for prop reading.

Q: Is this Trutach II Optical Digital indicator an FAA/EASA approved item and ifit cannot be installed in the panel, can it be used as primary engine instrument?

This unit is not FAA / EASA approved since it is not intended to be installed in a panel. You will still need to keep an approved panel mount tachometer.

Q: Does this unit come with a Certificate of Conformity stating that it complies with some form of National Calibration Standard or aa certificate of calibration?

No certifications are available for part # 10-01021.

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