ORIGINAL: jwfswart
I thank you for the responses.
The clunk can move freely left and right up and down. It is a 1/4 inc roughtly from the back when i hold it vertically hanging down.
BUT when i hold the tank vertically upsidedown the clunk rests against a side and with a half tank of gas will be out of the gas and then draw air. I am using regular fuel tubing. I was contimplating two pick ups, one in the back and one in the front. But with half a tank flying up the front pickup will suck air.
Any further advice.
Actually, a clunk is almost always moved around in the tank by more than 1g of force. So lot's of times, it'll go where the fuel goes and find it's way easier than it does when we're holding the tank in our hands looking at what 1g will do.
You're spot on about two pickups. You're just increasing the opportunity to draw air with two pickups. Air is easier to draw than fuel. It'll always be drawn first.
If the clunk is 1/4" from the back when the airplane is flying straight up, but is blocked by the end of the tank when the airplane is flying inverted, then the pickup line carrying that clunk is way off center. Use the tubing that sticks through the stopper to reach to the center of the tank. Do it with a short reach of tubing, but have the flexible line centered in the tank. Then the clunk will reach all around the back equally.