After run oil is kinda a joke. If you dry run the engine, you are left with the component of the fuel that drops out when the fuel is vaporized... i.e. OIL. In other words, a dry run burns out the fuel and just leaves a bunch of oil in the engine. If you need proof, dry run a engine at the end of the day. Open the engine up. You will see oil all over everything. It is not fuel, just the oil. Need proof? Try to light the stuff... it won't because it is just the oil.

Adding after run oil (as long as it is the right oil) isn't exactly a bad practice, but it is not required IMO. The idea that that is somehow magically driving the fuel and water out is bunk. If the oil has additives, it may help prevent some types of corrosion, but the oil that is already in the engine does that too. In other words, dry running is a lot more important that adding after run oil.

I can't really speak for the YS60 heli, but I have owned many YS4S. I have a YS140L that has over 60 gallons in it over three years. I never used an after run oil. Bearings are fine. No rust. I will use Mobil 1 total synth auto oil when I rebuild the engine after a gasket change, but that is it as far as adding any type of oil. We don't have too much salty sea air here in Lincoln, Nebraska (unless the wind blows really hard from the south ), but we do get extremes of weather and high humidity.

With respect to YS, I'd avoid any castor based oils. Reps at the YS booth in Toledo indicated to me that it can cause problem with the regulator as well as other carbon and gumming issue in YS4S. Don't know if the same "other issues" applies to the 60 heli, but the regulator issue would.

Again, I'm talking YS here. Some engines need castor. Always check your engine manual.