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Old 04-25-2014, 06:33 AM
code11 is offline
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Question
RPM from electronical ignition to telemtry

If I've got it right, the Job of an electronic ignition is to prepare the pulse of the magnetic capture electronically to control the flashing arc on the plug(s). Additionally some EI have an output to measure the RPM.


What electronic components are needed to use this signal - of course I don't really know the spec of the signal - by telemetry?


Wouldn't that be much more intuitive and easier than any optical or additional magnetical gathering of the RPMs like the telemetry parts available do?


In my case, I use the following components:


- DLA64 with its EI
- Futaba Telemetry System



... or am I completely wrong about this?
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Old 04-25-2014, 12:00 PM
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Code11... super easy with the Futaba Telemetry... All my planes have rpm telem on my 18MZ

* Simply unplug the servo connector between the ignition box and the sensor and install a "Y" harness in between.
* Plug the male end of Futaba telemetry module into the empty lead of the "Y" harness.
* Before plugging in the telem plug, disconnect or cut the red wire on the plug (prevents sending power to the igntion from your Rx)
* route the telem back to the SBUS2 port of your rx.

So, what you are doing is using the same pick-up sensor to feed signal to both your ignition and telem sensor.

Trevor
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Old 05-06-2014, 07:03 AM
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Hi Trevor
I'm almost sure I know what you're describing.
Is it the magnetic sensor (20.SBS-01RM) of Futaba you're using?
And does this work no matter what ignition I'm using?
Thanks for your help!
Bruno
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Old 09-03-2019, 02:44 PM
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Quote:
Originally Posted by tbrum View Post
Code11... super easy with the Futaba Telemetry... All my planes have rpm telem on my 18MZ

* Simply unplug the servo connector between the ignition box and the sensor and install a "Y" harness in between.
* Plug the male end of Futaba telemetry module into the empty lead of the "Y" harness.
* Before plugging in the telem plug, disconnect or cut the red wire on the plug (prevents sending power to the igntion from your Rx)
* route the telem back to the SBUS2 port of your rx.

So, what you are doing is using the same pick-up sensor to feed signal to both your ignition and telem sensor.

Trevor
I have a DA120 that I want to get RPM data from. I tried Trevor's method above without success.

The magnet sensor that comes with the Futaba RPM telemetry device works on the DA but there's no easy way to mount it to the engine. I've also tried replacing the Futaba magnet sensor with a DA ignition sensor and also a DA hall effect sensor with no luck.

It should be possible to hack a DA sensor to insert the Futaba magnet sensor into it. I'm just not crazy about jury rigging something that sits so close to the crankshaft, subject to vibration etc.

Has anyone else gotten an RPM sensor to work on a DA? Please share your setup and mount.
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Old 09-03-2019, 03:53 PM
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Give me a few dimensions/sketch and I will design a mount for that sensor that can be mounted (RTV will work) on the crankcase front, opposite of the inductive pickup, and 3D print it for you. Holliston is not that far from Hampton, NH...
Then once it is proven, I will share the .stl model for all to use.
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Old 09-04-2019, 12:00 AM
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Originally Posted by ghoffman View Post
Give me a few dimensions/sketch and I will design a mount for that sensor that can be mounted (RTV will work) on the crankcase front, opposite of the inductive pickup, and 3D print it for you. Holliston is not that far from Hampton, NH...
Then once it is proven, I will share the .stl model for all to use.
Cool! That would be great. I've attached the relevant diagrams from the instruction sheet and some photos with dimensions. Note my measurements show it's slightly larger than in the manual.

Sorry for the mix of inches and mm. I could also send you the sensor if that would help.

You may already be aware that the engine has a second set of mounting holes for a second sensor exactly where you were referring to - opposite the ignition sensor. RTV not required and can be removed for maintenance etc.

Do you need the relevant dimensions of the DA120 crankcase & mounting screw holes?

I'm not sure it's possible to ship from your place to mine so I think I might have to drive up to wherever you fly around there to pick this up and test it out . Next few weekends are fairly tight but we'll find a time.

Steve
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