Iain
5th October 2002, 09:01 AM
I worked for a conservation department several years ago and at the end of summer a group of science officers went up in a small cessna to start controlled burn offs.
They used what was essentially a table tennis ball filled with potassium permanganate and had a large syringe and would inject the ball with glycerine.
This being done they would toss the ball out of the window and it would ignite about 20 seconds later and start the burn.
About 100-200 of these balls would be tossed out in a line to create a burn off line.
The science officers got fed up with injecting and throwing and got the 'Mr Fixit' to make a machine to do the job for them.
The master pice arrived, it was a steel box with a hopper to one side to hold the balls and a little gate to release a ball into a tube.
The gate would open and the ball would drop into the tube, the syringe would come in from the side, inject and retract then a bottom gate opened and the ball released.
Sitting on the test bench it worked perfectly.
The device was fitted to the aircraft and the tube extended through the bottom, skyward bound and off towards the burn off area. I wasn't in the aircraft but I heard all about it.
Our brilliant science officers, upon starting the machine at about 500' discovered venturi effect, we heard that when the first ball was injected and the bottom gate opened the ball blasted back up into the hopper and the whole lot flew into the cabin.
It was apparently quite an exiting twenty seconds trying to locate the 'hot' ball.
They used what was essentially a table tennis ball filled with potassium permanganate and had a large syringe and would inject the ball with glycerine.
This being done they would toss the ball out of the window and it would ignite about 20 seconds later and start the burn.
About 100-200 of these balls would be tossed out in a line to create a burn off line.
The science officers got fed up with injecting and throwing and got the 'Mr Fixit' to make a machine to do the job for them.
The master pice arrived, it was a steel box with a hopper to one side to hold the balls and a little gate to release a ball into a tube.
The gate would open and the ball would drop into the tube, the syringe would come in from the side, inject and retract then a bottom gate opened and the ball released.
Sitting on the test bench it worked perfectly.
The device was fitted to the aircraft and the tube extended through the bottom, skyward bound and off towards the burn off area. I wasn't in the aircraft but I heard all about it.
Our brilliant science officers, upon starting the machine at about 500' discovered venturi effect, we heard that when the first ball was injected and the bottom gate opened the ball blasted back up into the hopper and the whole lot flew into the cabin.
It was apparently quite an exiting twenty seconds trying to locate the 'hot' ball.