% Power Calculation

[shenweas]

How is the % power calcuated on the Skyview?

I notice that it seems to take into account leaning to some extent but am now overcome with curosity with the specifics.

 

[Edwardoc]

I'm sure Dynon will answer but my understanding is the factory HP data for what ever engine you load in the software is stored in the system and it looks at your altitude, MP, Temp and RPM and maybe some other sensor inputs and using the stored data, calculates the HP and %. The inputs have to be accurate for the calculation to be right.

 

[dynonsupport]

Percent power is calculated using everything you would find on a standard Lycoming or Continental power chart. MAP, RPM, OAT, Altitude, and fuel flow are all used. It looks it up just like you would on the chart. These complex look ups all assume you are ROP. It's also critical that your EMS use things like altitude and OAT since they can change the % power by over 20%. A lot of EMS systems seem to think you can do it with just an RPM vs. MAP table, but look at any power chart and it's clear you can't ignore the air density effects.

The charts also have data for lean of peak operation, which is actually much easier. If you know you are LOP, % power is just fuel flow multiplied by a constant.

The real trick is figuring out if you are ROP or LOP automatically, since the number you calculate will be totally wrong if you use the ROP chart when you are LOP. How we do that is not something we can share since we're the only ones that do it.

 

[DonFromTX]

Good grief, what else does this magic box do that I did not know about!

 

[Edwardoc]

It knows who you are and where you have been and where you are going. Be careful now ;D