ORIGINAL: alasdair

Anyone used the Orbit clunk? Was it OK?
I used one for the first time in a new own design model recently, feeding a Wren MW54 mk3 from a 2 litre tank. At all throttle settings it tended to draw bubbles, even when the tank was full. Where could they be coming from?
I changed the tubing, I changed the brass fittings and the tank stopper, I wire locked all the connections, but still I was drawing bubbles all the time, and I had 3 or 4 flameouts in flight.
Then I removed the Orbit clunk and fitted a pleated paper one from Mick Reeves and the bubbles stopped and I've had a dozen flights without a flameout.
That made me think it could be the clunk, but where did it manage to find air bubbles in a tank that was full of fuel, and the pipe and clunk were wholly submerged, and there was no frothing in the tank?????