nitro engine tachometer

[Kyle Ebisutani]

Currently, what are we using to monitor and or acquire nitro motor rpm.
I am interested about all systems and devices.
acoustic/audio tachometers
data acquisition systems (telemetry and non telemetry)
I realize there have been previous posts regarding this but technology is changing so rapidly I felt it would be a good time to revisit this. Please post some information about your system and or a link where we can view specifications and also where we can purchase it from.

 

[dwilfong]

https://www.eagletreesystems.com/

 

[Kyle Ebisutani]

Thank you David. I've heard of that system before. That is a very nice system, probably using the optical tach.
I get it that the engine tachometer may not be a very popular tuning tool.
May I ask if anyone is using a smart phone with an acoustic/audio tach application? Almost everyone has a smart phone nowadays. Applications are reasonably available and inexpensive but are they consistent and somewhat accurate?

 

[dwilfong]

I used the magnet hale affects system the optical did not work so good.
It is a great tool to get to know your tune on a boat.
It will log RPM. GPS .SPEED and eng temp.
It can also log G force if you like and throttle position.
You can play it back on Google maps to see what your boat is doing in real time on the water.
If you know how to use it there is no better way to tune your boat set up.
It will give you a feel for what is what if you are just starting out.
This way you can put a relation ship to how the boat looks and what it truly is doing.
You will find you will not need it after awhile because you can see and understand what is going on.

 

[Kyle Ebisutani]

I truly believe this information in a real time graph will give you invaluable data to back up your performance. Sometimes it's something you just want to know. But most of the time, it's convenient and hard to beat judging performance on what you see and hear happening. I get it.
The systems are great if you know how to interpret the data...let alone install it. I think you really need to be passionate about this data because hooking up all the stuff can be a chore.
I read about the eagle tree tachometer and am familiar with optical triggering systems as I use them to verify speeds on lab centrifuges. These can be inconsistent at times. (Accurate but inconsistent) I would imagine that experience would be required to mount the optical p/u for proper and consistent operation.
As far as the hall effect tachometers go, there is a magnetic p/u which I agree would be less critical to mounting BUT I am curious of the physical specifications of this magnet attached to the rotating source. Is it a disc? Or is it a magnet sticker (as thick as paper)? Having a magnetic disc detach from a rotating source at 20,000 rpm would be a story to write home about!
In addition to this madness, this system is hardware and will weigh down your model (especially 12's and 21's) and make the model perform differently? Yes, nothing like real time data. I realize that acquiring data from different sources will be hard and or impossible to graph real time but sometimes you just want that one parameter. In this case associate rpm sound to a number (rpm reading). I realize a lot of boaters have used a radar gun to monitor speed and now they can associate the movement of the boat to some mph. And some of us are pretty good at it now w/o using a measurement device. I think a lot of us are curious to find out what what rpm that sound is on that outstanding performing boat.

 

[dwilfong]

The magnet is a small rare earth about 1/8" round you drill a hole in the fly wheel just a tad smaller and press it in.
Mine fell out a few times before I got the hole size all figured out.
Was at 32670 RPM and did nothing to the boat.... I know what RPM because it stopped logging RPM.....
Don't be SKEERD it will not hurt you or the boat and it is no harder than setting up the boat to start with.
If you have a laptop you can down load it at the pond and look at the run.
If you use the v-4 you can mount the LED display on the boat and it will tell you top speed and RPM. gust shut it of to reset.
I had this system in my .21 no problem and it weight nothing.
If this little amount of weight makes a difference you have bigger problems.

 

[Chris Haley]

Personally I would never use a Hall Effect Sensor as they require disturbing the rotating assembly of you drive system.
when I built turbine engines I always used a Banner optical HIGH speed sensor/counter. I was able to measure 143,000 rpm's. This was around 2001. No videos but detailed documentation. Google "Haley Turbine Projects" It was so much fun!!!

 

[Jim Allen]

I use the Acoustic Tachometer shown in the photo for both nitro & gas engines. Very accurate readings even with sound taken from an internet video. It uses the doppler effect to measure RPM.

Jim Allen

 

[Chris Haley]

I just checked it out. I was plagued with ads. Sorry. I did finally get around evrything.

 

[Terry Keeley]

Eagle Tree's V4 is being phased out unfortunately, prolly due to the newer radios with telemetry. It does work tho if you have the tenacity to install the hardware and then interpret what it's telling you.

 

[dwilfong]

Eagle Tree's V4 is being phased out unfortunately, prolly due to the newer radios with telemetry. It does work tho if you have the tenacity to install the hardware and then interpret what it's telling you.

That is a shame thy are getting rid of it.
I have 2 data loggers and 2 V-4 and all the stuff to go with them.
O that's right Julian has one of the loggers I put in his Twin ....LOL
The problem will be when the units get a glitch and no support to fix it.

 

[dwilfong]

Disturbing your drive system????????
Terry is your drive system disturbed?????????
It is hard to keep the black black and the white white on a nitro breathing grease slinging beast......ask me how I know.........

 

[Kyle Ebisutani]

Thanks guys.
David, glad the magnet didn't come after you in the pit. I was often wondering about that. But glad to know you got the installation process is ironed out. Terry's installation shows proof of that. Super nice installation Terry! David, it's also great to know of your experience with the optical sensor too! It sure does get messy near that flywheel. maybe the optical sensor is set up for a different modelling modality. For example, if you go through the Futaba radio sensors, the instruction informs you how to set up the system in an aero environment. I'm sure it's adaptable for a nitro marine environment though. Unless you purchase it and experience it yourself, you would not know any better. In the past I did call some of these mfg systems support advisers and they did give positives and negatives to certain parameters success in the nitro marine environment. If going against advise, I guess the consequence of risk is yours to take. That's why I'm skeptical to download some of the acoustic tach apps to my phone. The adware may out perform the tachometer! the reviews are scary!
Jim, I like that acoustic tach. Looks like +/-500rpm, too bad that Koster is no longer readily available for retail. Does anybody use the HyperTach 50K sold by hyperformance products. Think this one is +/-1000rpm or is it just the displays reads in the thousands?
Again, thank you Terry for posting your eagle tree hall effect tach. Super nice install and download to real time. Artifact is virtually non-existent!

 

[shoboat]

Kyle,

I had the tachometer from HyperTach and it was not accurate at all.
I think some of the newer phone app tachometers are pretty close now.
Thanks For Reading,
Mark Sholund

 

[John Beardslee]

Eagle Tree's V4 is being phased out unfortunately, prolly due to the newer radios with telemetry. It does work tho if you have the tenacity to install the hardware and then interpret what it's telling you.

Terry, did you consider mounting the magnet on the rear face of the flywheel instead of the O.D.? Mounting on the rear face takes most of the centrifugal force off the fastening process. I was able to use 5 minute epoxy with no failures for years.
Thanks John

 

[Terry Keeley]

Terry, did you consider mounting the magnet on the rear face of the flywheel instead of the O.D.? Mounting on the rear face takes most of the centrifugal force off the fastening process. I was able to use 5 minute epoxy with no failures for years.
Thanks John

Never thought of putting it there, what's your sensor mount look like?

I put mine there to use the motor screws to mount the sensor but have actually now mounted it to the hull.

This is when I tried the Futaba gyro sensor but the mount I'm using now is similar:

 

[John Beardslee]

Terry it’s mounted off the engine lug, very much like Dave’s. I use a similar Hall Affect sensor on my RC heli Rev limiter/governor. I don’t have etree sensor down here but do have one from my heli, here’s a pic of how I did it. The sensor is covered with heat shrink for protection.

Thanks John

 

[dwilfong]

I fond the best way to look at the info is on the dash board use the gauges to watch the speed and the RPM.
Put them side by side on the screen set up and then put the compass net to them.
This way you see the arms moving and you are not gust watching number on a screen.
Try this some time and tell me what you think.
That way you can see the average Highs and lows much better in you mind as it is running.
The compass will spin when you are in the corner and stabilize when in the straits.
Much easier to under stand with the visual reference than all those number and a grafts to tune for heat racing.
Just a little tip from spending many hours testing with it.
O and you will not shoot your eye out...........LOL

 

[LohringMiller]

We ran Eagle Tree data loggers on a lot of boats, from 3.5 cc outboards to a full size electric hydro. With the GPS for speed and position and an rpm sensor you have a lot of information. An exhaust gas temperature sensor is frosting on the cake for IC engines. The various other sensors help as well, but speed and rpm are essential. The telemetry wasn't particularly helpful. Below are a couple setups and some interesting data. The first setup is on a 3.5 cc Rossi outboard with the comparison data from machining off head fins. The second is a similar rpm sensor on the electric hydro with the data from the record run. The hall effect sensor wire is the very small wire into the lower unit. We had to sense off the output shaft because the strong electric field around the motor confused the hall effect sensor.

Lohring Miller

 

[John Beardslee]

FYI guys I’m sure you all know this but thought I’d mention it anyway. Make sure your magnet is oriented correctly. The Hall Sensors are pole sensitive thus don’t work well if the magnet is up side down.
Thanks John