bullet wrote:My apologies, my initial question should have contained the following info:
The safety advantage when one engine quits is what I`m curious about between the two models and the difference in effect (if any) of whether the left or right hand engine quits.
Is the safety advantages of the PA 39 such that you would rather wait for a PA 39 to become available and ignore a PA 30 which is available or not ?
Hi Bullet. I believe that there is very little, single-engine, aerodynamic advantage in having the right engine turn the wrong way. It is meant to eliminate the "critical engine" problem but I think it was more of a marketing ploy because the Twinco got a bad rap initially for training accidents. The problem was that being the cheapest twin on the market it was the one everyone used for training, so it was bound to have more accidents. Also the FAA brought in ridiculous rule that said critical yaw had to be demonstrated at (I think) no higher than 1000' AMSL - in order to have the max possible power on the good engine. A very silly rule which killed a lot of folks. I understand they eventually did away with it.
I have tried to see the difference in the air and not had any joy. If there is a difference it is probably counteracted by banking an extra 1 or 2 degrees into the live engine.
Anyhow, I believe the short story is that contra-rotating props were more a marketing thing than an aerodynamic one.
Soes that answer your question?