DA 120 with onboard Tach.

[Robbins]

Oh Yea.. forgot to say that there are three magnets on the prop hub. Should be interesting.

 

[49dimes]

Oh Yea.. forgot to say that there are three magnets on the prop hub. Should be interesting.

As far as I can tell you have no "additional" set of threads on the DA35 to attach the hall sensor ( clamp it on ). The new DA ignition is like the 3W's microprocessor units. I don't know for sure on the DA ignition but 1 of the 3 magnets should have the S pole facing up and the other 2 N pole facing up. The hall sensor should not have any trouble reading the S pole magnet. So you should get steady readings.

 

[Robbins]

I will glue a heli fan magnet to a stick and see which one it is. If there is one it will me easy.
Thanks dimes

 

[Alky6]

Here is what I did to add the rpm telemetry (spektrum TM1000) to my DA 100 without the extra mounting holes already existing. I used an RCexcl hall effect pickup and cut off the mounting ears. Used a fat popsicle stick and cut out where the sensor goes. Had to glue the sensor in upside down to work with the DA magnet polarity. Then I trimed out a v-notch on the opposite side of the popsicle stick to allow it to sit down over the radius of the crank housing. Epoxied everything in place with 5 minute epoxy. It was a two step process. No resistor installed in circuit goes directly into TM1000. It is sensitive to fast changes in rpm and irregular signals. Tends to go maverick until the high rate of change on acceleration or deceleration is complete. Works well, other than that quirk once in a while.

 

[49dimes]

That will get the job done! My DA 70 did not have the additional holes either so I made some and tapped to 6-32 because all my 4-40 taps are broken. Need to get to the hardware store.

 

[Alky6]

Nice! Very clean. Did you tap blind holes,or drill through? Reason I ask, is that I do not know what the crank support looks like at the end. I opted for the lazy route this go around. Perfect solution is to drill and tap some holes.

 

[49dimes]

Nice! Very clean. Did you tap blind holes,or drill through? Reason I ask, is that I do not know what the crank support looks like at the end. I opted for the lazy route this go around. Perfect solution is to drill and tap some holes.

Being that the prop hub is fluted and tapered on the back side I was able to bench mark with a hand punch and use a hand drill to drill and tap the holes with out having to remove the prop hub. The wall thickness of the crank case front bearing bore is about 3/16". I would imagine your DA100 is similar with the exception of the taper and flute. You probably would be best served to go ahead and remove the prop hub if you desire to drill and tap you some holes.

Removing the hub is not difficult. 13 mm deep well socket and a battery powered impact driver with a 3/8ths socket drive adapter can break the shaft/hub adapter nut free with out having to lock the crank shaft. Works great for putting it back on too!

 

[Alky6]

Thanks Kelly! I just happen to have all those tools, along with some 4-40 taps as well. Thanks again!