AC - I know where you are coming from but you can't disregard the H-V curve just because you aren't in level flight - you are slightly better off being in a descent as the power is a bit lower but not in the latter stages as ETL is lost.
aa777888
Except that when you feel that vibration you are already below ETL and what you are feeling is the vibration from the transverse flow effect.
have to disagree with that - the vibration is ETL not transverse flow and you can tell by the lower power riding that vibration that you are not below ETL. You can show a demo of transverse flow in a transition into forward flight - it starts much earlier than ETL and there is no vibration until just before ETL (you are powering through the vortices to get through ETL) and then the nose pitches up due to flapback.
As for single vs twin - it doesn't matter unless you are doing PC1 profiles in a twin.