SureFly feedback before I pull the trigger

[Rvator97]

Originally Posted by Rvator97

As both of my mags were wired to Dynon EMS via P leads, sounds like I need to either get the Surefly tach board , OR install a magnetic pickup tach sender in the remaining slick mag. This tach sender would be connected to left side tach input on Dynon EMS, ( per Dynon install instructions). As Tom said, as long as mag is turning, tach info will be sent. This would solve the run up check issue as I would not lose rpm info when running on Surefly alone.

Good point Steve.....BTW: Do you notice/ hear ANY drop in rpm when you do run up and turn switch from Both to Surefly only?

[Steve Iacoviello]

Originally Posted by Rvator97

Good point Steve.....BTW: Do you notice/ hear ANY drop in rpm when you do run up and turn switch from Both to Surefly only?

From what I hear during runup is that the rpm drop is less on the Surefly versus the right mag. The rpm drop on the mag is about 70 rpm. There is a drop on the Surefly but less. I am comfortable with it. It appears to start better but to be honest I was not having starting issues prior to the Surefly installation. I currently have the Surefly set for fixed timing.

[Sam Buchanan]

I see 70 rpm drop on the right Slick and 50 rpm drop with the Surefly.

[TimO]

I would be interested if anyone has the actual details on what is needed to actually integrate the surefly tach, from a signal perspective. I know they sell the tach board that has various tach signal outputs you can use. My EIS is the GRT EIS, and works fine with a 39K resistor on the mag p-lead and works on lightspeed ignition directly just fine.

I emailed GRT in advance to see what they recommend for changing the resistor value so that the tach signal works properly with the surefly, and they simply told me it doesn't work with the EIS. That answer doesn't sit well because after all, it's just a pulse signal. They said I could buy the UMA tach sensor and use that.

Surefly told me the mag p-lead signal is something like 200-300V whereas theirs is 60V, so the resistor would need to change but that should be about it.
Maybe this would be the solution with the Advance Flight question above too?

My EIS has dual tach, and I'd rather not just add the UMA tach sensor when I should be able to do a little adjustment to resistor values and get tach input working. Just hoping someone has maybe done the work already.

I'm not yet ready to install my surefly systems on my 2 planes, but when I am done, it'll be Lightspeed + Surefly, most likely with the surefly running straight timing. If nobody has an answer on what will make it work with the EIS, and I figure it out after I install them, I'll post here. I would think the same fix would work on the Dynon/Advanced stuff.

[Rvator97]

Originally Posted by roadrunner20

I'll be watching your flight tests, as I was the one that returned my Surefly while swinging a catto 3-blade and having kickbacks. This was prior to others suggesting a timing retard to correct it. My kickbacks were numerous & is why I returned it. On a cross country last month, my starter failed & I will be replacing next week. I suspect my starter failure is related to my prior kickbacks.

Have started her up four times now..... starts great, no kickback issues. 🤞
Flight test tomorrow .......

[TimO]

Sort of replying to my own post above. A friend who already installed his Surefly did some testing for me today with an oscilloscope. From the Surefly FAQ, the tach signal is "60VDC pulse with 10Vdc offset". What that means in effect is that there's a steady 10VDC coming off the tach signal, and the pulse goes up from there. That's probably why the engine monitors have such a hard time with it. They need to get down to zero or something much lower than 10V to register the low end of the pulse.

So, he tested it today with an inline film capacity of 1uF, and when you look at the scope with that installed, the flat DC voltage doesn't pass, but you still get the pulse waveform.

I won't be installing mine for a little bit yet, but when I do, I'm going to try it with that inline capacitor and a resistor, and see how the GRT EIS handles that. My guess is it'll work fine, because my current 2 tach are Lightspeed and mag p-lead and they are vastly different, yet the EIS config is the same. Not all engine monitors may like a big pulse but the GRT can handle 200V pulses with no issue.

At least it's encouraging that it should be workable.

[Rvator97]

First flight since Surefly install today. Engine started quickly. No kickback issues.
Ran beautifully.... very smooth. I did install a new harness and new spark plugs as well. Runup was like others have posted... about 60-70 rpm drop when running on right mag alone. By the sound of it, the rpm drop when switching to Surefly and mag off, was about 30-40rpm.
Maybe it was just me, but it sure seemed to have increased power on take off roll! Weather was not great, so didn’t get to do a lot of data collection at higher altitudes. As expected, CHTs were 20-25 degrees higher than before. So far, so good.
FYI: Engine is AeroSports Power 0-375 205hp.

[mfcummings]

Originally Posted by Rvator97

First flight since Surefly install today. Engine started quickly. No kickback issues.
Ran beautifully.... very smooth. I did install a new harness and new spark plugs as well. Runup was like others have posted... about 60-70 rpm drop when running on right mag alone. By the sound of it, the rpm drop when switching to Surefly and mag off, was about 30-40rpm.
Maybe it was just me, but it sure seemed to have increased power on take off roll! Weather was not great, so didn?t get to do a lot of data collection at higher altitudes. As expected, CHTs were 20-25 degrees higher than before. So far, so good.
FYI: Engine is AeroSports Power 0-375 205hp.

Walt, how is the timing set up Variable or Fixed?

[Rvator97]

Variable.

[mfcummings]

Thanks, Walt. I changed mine back to fixed yesterday, with summer temps my cht?s were getting to high. I did help bring them down around 15 degrees.

Mike