Dynon percent power reads 0% at low power settings

[prkaye]

My reading of percent power from my Dynon goes down to 0% long before the throttle is back to idle. It's showing 0% when I know the engine is doing some work (because it's turning the prop at faster than idle speed). Is this normal?

[647jc]

Yep, mine does the same thing.

Also something else about percent of power reading on your Dynon EMS you may not be aware of. The percent of power calculation is made by Dynon using the RPM red line value you set in the EMS. Dynon assumes the red line value is the RPM at which the engine generates full power which for our engines is 2700. Now, if you have a Sensenich prop that has a 2600 RPM limit and you set you EMS for a 2600 RPM red line limit in order to get EMS warnings when you approach or hit the prop limit, then your percent power display values will not be as accurate as they could be. I have my red line set to 2600 and I think that affects the percent power reading by about 2 percent. That is, when my percent power reading indicates 77 percent power I am actually generating 75 percent power. Not a big difference but something you should be aware of.

Just noticed from your web site you dont have a metal Sensenich 2 bladed prop so you dont have the 2600 RPM limitation.

[breister]

Actually, there are two settings in the EMS that affect %power. One is max RPM, the other is total engine HP (which should equal 100% at max rpm).

Beyond that I do not know how they calculate - but considering that at 800rpm you are probably only generating about 1% thrust a 0% reading might actually be reasonable.

[Ironflight]

In all the EFIS's I've flown with %HP, I have found it's good to pretty much ignore the lower end - the equations are optimized for the upper half, where you want it to be accurate. I've never really had a need to precisely set power below 50% or so.

Paul