No actually it ( the loop in the ventline) is intended for either gas or glow and it works well for both. In my comment I am talking about the vent line not the fuel pickup line. If the tank is vented to the air (not getting pressure from the exhaust) and the nose is pointed straight down the tank will drain out of the vent line everytime. The only way to stop it is to loop the vent line back to the rear of the tank so that when the plane is vertical the fuel wont drain out because the head in the vent line is higher than the head in the tank. Obviously if the fuel tank vent is connected to the exhaust vent fitting then the point is moot.

The 3 line clunk system works great for gas and glow models as well. You just have to put a fuel dot in the fueling line after you fill. It totally eliminates the problem with fuel running out of the carb when you fill, if it is a problem at all. I only use it when I cannot access the fuel line due to a cowling. When the engine is exposed, I just pull the fuel line off of the carb inlet, fill and then replace the fuel tubing.