- Planes
- Engines
- Props
- Glow plugs
- Fuel
- Pit boxes
- Handles
- Fingers shields and chicken sticks
- Stooges
- Plane racks
Suggestions to Preston Briggs
This site was last updated on February 15, 2008.
An alternative to the fuel shutoffs shown in other sections is the fuel dump. The idea here is that when line tension is lost, a valve is opened, releasing pressure (and fuel) from the bladder.
Mark Hansen sent along these pictures of the dump he uses. He credits the basic design to Roy Heppenstall. Mark writes: "Operation is simple, the red tube that goes behind the sliding bell crank dumps the fuel in the event of a cutaway. All the parts to make the shutoff cost less than 5 bucks and it last virtually forever. I have been cut away in fast and the engine died instantaneously!"
When bagging up, the pit man places a hemostat on the dump tube and fills the bladder and pinches off the tube to the needle. Just before launch, say at 30 seconds, the pit person wraps the dump tube around the tail boom and removes the hemostat. The starter starts as usual, and the launcher lets go of the plane. As the plane accelerates, the dump tube unwraps and effectively arms the shutoff. Should the lines be cut, the bellcrank slides to the outboard side and the fuel dumps out the dump, eliminating pressure and causing the engine to die.
