% HP - Dynon vs AFS

[swatson999]

So here's an interesting discrepancy...the situation:
Me: RV-7A, Lycoming IO-360, Hartzell BA prop
Buddy: RV-7, Lycoming IO-260, MT 3-bladed prop

At altitude, in formation, both showing nearly identical MP and RPM (within .1" of MP, 10-20 RPM), approximately the same FF (maybe 1 GPH difference), his AFS shows consistently about 10% higher % of HP than my SV. E.g., I show 75%, he shows 85%.

The only difference is OAT, where mine is under the empennage fairing and reads 5-10 degrees F higher than his.

Does this make sense? We've done this on several days, at several different altitudes and there is always this difference (and we're matching speeds, as well, since we're in formation).

 

[dynonsupport]

Dynon uses a more sophisticated % power algorithm that factors in altitude, fuel flow, and LOP/ROP state, while AFS does not currently, so the discrepancy is expected.

 

[DBRV10]

Basicall the AFS unit is probably showing a lookup table for ROP operations only.

Dynon has always been correct with aROP/LOP cut over. when LOP the HP calculation is based on fuel flow.

In the certified world traditionally they have all been wrong, except the ORACLE. Dynon has led the way!