Yak52 install gotchas

[John Lucas]

I’m almost complete with installing HDX in the front and rear cockpits of my Yak. I have the dual ADHRs and will have EGT/CHT for all nine cylinders which will be nice. Does anyone know of any gotchas I should be wary of prior to firing up the engine with all of the avionics installed for the first time? I’m aware that the shower of sparks can cause some electronic noise that can potentially be hard on modern electronics, but am not sure if HDX has any protection from that built in. I’m sure there are other things I haven’t thought of and am looking for any suggestions.

 

[RV8JD]

From the SkyView HDX Pilot's User Guide:

"Power
SkyView displays require between 10 and 30 volts DC for operation. See the SkyView Classic / SE / HDX System Installation Guide for details on power consumption. SkyView systems have robust power protection that allows the SkyView system to be powered on during engine start."

From the Installation Guide:

"SkyView System Can Be On During Engine Start
All Dynon Avionics units in a SkyView system incorporate robust power protection that allows them to be powered on during engine start for full engine monitoring. SkyView displays require a minimum of 10V, and during engine start, it’s common for the electrical system to temporarily drop below 10V. If an SV-BAT-320 Backup Battery is not installed, SkyView may shut off / reboot. If you wish to monitor your engine prior to engine start, an SV-BAT-320 should be installed so that the SkyView display can switch to the SV-BAT-320 when its power inputs are not receiving at least 10V. The SkyView display will switch from SV-BAT-320 to aircraft power when its power inputs receive voltage above 10V."

 

[Dynon]

And that's really so they don't power off. You won't damage SkyView with drooping voltage (which is common). The displays may restart though. If you have a backup battery connected, that takes over and then you won't have any issues here.

 

[CanardMulti]

All well and good. I get that my backup batteries keep my screens happy during cranking, even with a low aircraft main battery. However, as I read the OP's question, he might be wondering what effect the 'shower of sparks' rapid voltage fluctuations, or perhaps other form of feedback generated by all that make and break of the points, might have on his system. Dynon input?

 

[Rhino]

There shouldn't be any significant voltage fluctuations that would affect the Skyview unless something is very wrong. Shower of sparks doesn't really work the way many people seem to think it does. It just shuts one magneto off and rapidly switches, or pulsates, the voltage used to create a spark with the other magneto. The spark itself is no different from the spark created anytime your engine runs. The shower of sparks system just changes the timing and frequency of the sparks to make starting much easier. There is no massive electromagnetic field being created, and no inherently dangerous variations in system voltage. Mooneys and many other aircraft use these systems. I've never heard of anyone frying their Skyviews with it. Most of these systems come with all solid state components these days, as opposed to mechanical relays, so their possible effect on an electrical system is even less than what is minimally was before. Electronically speaking, any such rapid fluctuations are inherently less dangerous on a DC circuit, though they can be difficult to filter out sometimes. Typically they only result in a little electrical noise, which won't hurt a Skyview. There's no shortage of wives tales circulating on this topic. They've been circulating ever since those ignitions were invented. So it's easy to see where one might have heard people voice these concerns. But as far as some sort of inherent chronic or systemic issue goes, they appear to be nothing more than persistent urban legends. I don't rule out the possibility that a few scattered issues have been observed. I do know this issue has been claimed before and found not to be the case. But given the rarity of it, I don't find such claims credible. YMMV

http://www.aeroelectric.com/articles/Shower-of-Sparks/ShowerOfSparks.pdf

 

[John Lucas]

And that's really so they don't power off. You won't damage SkyView with drooping voltage (which is common). The displays may restart though. If you have a backup battery connected, that takes over and then you won't have any issues here.

I do have the backup batteries for both displays. The Russian electrical system reputedly can be hard on modern avionics during start. Thanks Dynon and RV8JD.

 

[Rhino]

Checked the system on the M-14P and it operates essentially the same as on aircraft in the US. The timing and frequency of sparks is altered to provide for better starting, but the sparks themselves are no more powerful than what they are when the engine is running. The reputation for trouble has been mainly related to radios, because the rapid sparking creates electromagnetic interference (EMI). Radios and audio systems are those most easily susceptible to EMI, so that makes sense. Absent something wrong with the components or wiring, there should be no fluctations on the electrical system that pose a danger to your avionics, particularly the HDX. Your radios and audio systems likewise should not be in danger unless they're very old technology. They just might get noisy during start, but you don't really need those during engine start anyway. If people have heard such noise in their radio or audio during engine start, it's quite easy to see why they might suspect danger to other systems. It's a really disconcerting sound. But noise isn't a danger to the HDX.