ORIGINAL: Parkerm
Lastly, I have an old RCM magazine with a construction article for a .40 sized floatplane that the author fitted with one of the early OS Wankles and he speaks of it having a factory nipple on the engine casing (but no provision for a nipple on the muffler!).
There is a nipple on the engine and although it is not mentioned in the Wankel Instruction book it serves the same purpose as the extra nipple on the bottom of most four strokes. The nipple dumps the excess oil that accumulates between the back bearing and the backplate. It is not a pressure tap. Trust me.
I disagree. That nipple is not mentioned in the manual and I left it open as you say. The engine ran so hot that it was smoking even when the needle was backed out so far that there was cold, raw fuel spewing from the muffler. The problem went away as soon as I hooked it back to the tank (2-line tank system). The engine runs much cooler now.
Regarding power, it has plenty, but it is a fuel hog. I can't get 10 minutes on a 9 oz tank and there's no idle adjustment. Usually I can get mine idling ok but times when I can't I just have to live with it.
Overall it's a cool engine but I bought mine in Germany where it cost over $100.00 less than even when on sale here in the states. I would not use it in a twin because of the idle thing. There's no way to adjust it and sometimes it dies at low throttle where a two-needle engine of similar power is more reliable.
But mine is a power house. I haven't tached it but it turns a 10 x 6 with authority. For my current model that's too much pitch. I've ordered an 11 x 3 and an 11 x 4 for it. I hope it turns the x 3 well because that's the prop I'd rather use. With the 10 x 4 I'm currently using I can't get the plane slowed down enough to stop ballooning when I'm trying to land it.