Electronics International R-1 Rpm Tachometer

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Part# 10-25200
MFR Model# R-1


These Digital/Graphic Instruments are solid state and hold their accuracy over time and a range of environmental conditions. The colorful Graphic Analog display emits green, yellow, or red light enabling the pilot to spot problems immediately without interpreting a needle. The Digital display constantly provides an exact indication of each instrument function. Gauges mount in 2-1/4" instrument holes. These instruments (except fuel level) are STCd & TSOd for certificated aircraft.

R-1 Tachometer

The R-1 is a precision RPM instrument featuring a 210 degree graphic analog display and a full four-digit digital display. The 10 RPM resolution allows for precise RPM settings. The R-1 features a tach time recorder which records the time the engine is operated over 1300 RPM as well as an automatic flight timer which records the time starting when RPM reaches 2000 (takeoff) and then drops below 2000 (landings). Installation of the R-1 is simple. It connects to the mag. lead through isolator and requires no cables. It is backlit and operates on 12-24volt systems. Wt. 10 oz. Max. Digital Range 5000 RPM. Accuracy 1%. Specify red line, yellow & green arcs, and magneto models, as well as aircraft make & model.

E.I. products include all documentation and certifications

R-1 Configuration Worksheet (Required for Order)

Customer support member will reach out for completed worksheet after order is received.
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -

FAA Approval

  • STC'd, TSO'd, PMA'd
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Very satisfied! I installed one in my Grumman Yankee it works very well. I just ordered a second for the Grumman tiger project.

Ronnie M
November 3, 2023

Works fantastic in my Pitts S-2B. As an added Bonus: the factory can program your tach time in the total time of the device and ship it to you. Having two tachs with the same, and accurate tach time is awesome.

October 28, 2023

After some errors and confusion during the order process, EI reached out and was more than willing to rectify the situation. Good customer service, friendly and knowledgeable staff. As for the unit, Ive had it installed for just over 6 months now and have zero complaints. It is superior to the factory mechanical gauge in every way. Run ups are easier and fine tuning engine speed during cruise has never been easier. My experience with this unit has led me to purchase additional instruments made by EI.

Seth H
May 19, 2020

I’ve bought these twice and love them. Many people don’t realize that old faces in old airplanes are usually about 200 rpms off, they die a slow death. This is highly accurate and was about a 90 minute DIY project with supervision.

Av- F
June 23, 2018

Drop shipment arrived earlier than expected.. Thanks to aircraft spruce and electronics international

Sansone S
June 6, 2018

Easy to see and operate. The mag drop feature works well. Takes some getting used to looking at a number instead of a needle. The lights help though. Installation took the avionics tech about three hours. No surprises at all. My only complaint is that the instrument doesn't come in 3-1/8 size. The included adapter plate worked well though.

Edward S
August 15, 2015

Very disappointed. I bought this for a stock PA-34/200 Seneca. They are not plug and play. The tachs are almost 2 inches longer than the mechanical and the right tach will not fit in the mounting as it conflicts with the parking brake handle. So you would have to let the tachs extend about an inch out of the panel. This is not noted on the installation instructions nor advertising.

Accessible A
July 28, 2022

Mine is about 3 or 4 years old and has become sensitive to humidity as it reads a very high number - even when the engine isnt running. I called customer support and they said that it can be resealed for $125. EI equipment is only warrantied for 1 year. I would think that my problem is based on defective materials, workmanship or design. The factory new unit didnt last long and there was no mention as to how long resealing would last. Theyve been making these units for quite a few years and this is a known problem.

Kenneth P
January 16, 2019


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: Does this only come in 2-1/4" gauge?

Yes, the R-1 only comes in a 2-1/4" gauge.

Q: What is the EI RC1 RPM TACHOMETER CAP 10-01223 listed accessory?

The EI RC1 Cap is used to cap off an existing oil pressured mechanical tachometer cap drive line so oil isnít spilled when replacing the new electric tachometer.

Q: I have a Pitts S-2B. I want to replace both front and rear Tachs. Can I run two tachs off the single drive?

Per EI, since this an electronic tachometer, this does not use a drive cable. This picks up the pulses from the magnetos which you tell you your RPM information. You can easily connect 2 of these electronic tachometers at the same time.

Q: Is this tach able to be used in a certified aircraft? Does this come with an STC?

Yes, The STC list can be found under the documents tab for the EI R-1 (10-25200)

Q: What information is required to order this instrument? I'm guessing red line and yellow arcs. Do you need current tach time of the tach that will be replaced?

Specify red line, yellow & green arcs, magneto models, engine model, and aircraft model. Current tach time can also be preset to reflect current time.

Q: Does the EI R-1 RPM Tachometer connect to both mags? How do you check your mag drop?

Yes, please see page 4 of the manual posted under the documents tab for mag drop procedure.

Q: Will a 1 amp circuit breaker be sufficient for this EI R-1 RPM tachometer?

Yes, 1 amp circuit breaker is recommended.

Q: Does this unit come with a 3-1/8 adapter plate?

Yes, an adapter plate for a 3-1/8" hole is included with this unit.

Q: Is the Electronics International R-1 tachometer approved for primary installation or backup only?

The E-1 is TSO approved and can replace your current primary tach.

Q: Can this EI R-1 RPM tachometer be hooked up to the Electroair electronic ignition? I do not see anything in the installation manual.

When you place the order for the R1 you will be asked for the type of ignition system. Per EI: the -LM version of the r1 will support the Electroair electronic ignition.

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