I took my rocket balloons to work the other day because I wanted to see if they sounded any different with helium and since we paid for a big tank at work, I decided to get a little more use out of it before they came to take it back. Well they didn't sound any different. I guess it was a dumb thing to try, but I proved rocket balloons are not related to vocal cords. One of the student assistants wanted a few to play with so I gave him some and later found one under the lunchroom table. Funny, he wanted to try one with helium too, but I told him it didn't work.
The balloons don't have anything in them to make the squealing sound as they fly, only a long floppy nozzle. Upon thinking about them more as I fished the one out from under the table with my foot, it occurred to me that the rocket balloon philosophy might be employed in pulsejet land.
What if you had a bunch of little floppy nozzles or "one-way valves" made of semi-stiff silicon tubing instead of petal valves which collapsed when met with the backflow of gases in a pulsejet? Of course you would also have to design a dish firewall to keep the hot gases away from the heat sensitive floppy reeds. But even spring steel will warp if not kept cool enough too. And leafed neoprene/spring steel reeds have been used in Tharratt's pulsejet for 7 hour runs.
"Withstands oven temperatures up to 500 degrees."
http://tinyurl.com/2jpg4e
So back to our adventure, it comes to mind the collapsing of one of those Lockwood tails, the implosion effect similar to what a rocket balloon must effect. Air races out the nozzle, walls collapse, repeat and rinse, etc. There may be a thousand things that can go wrong, but in theory flapping, flopping tubulettes might gate the airflow well enough to run an engine. Or even put them in "backwards" maybe, have the extentions dangling out the front of the engine like a star-nosed mole. As gases escaped, the collapse would occur, hopefully tricking the airflow fast enough to cycle out the back of the tailpipe.
If nothing else perhaps you could create a pulsating pulsejet effect, not caring where or which direction your thrust is going.
Lastly, I have some brass reeds from some air horns that I have unscrewed out of the curled horns with rubber bulbs that you squeeze. They are some left over from when I lived in Pakistan. These reeds are kind of like rocket balloons in that the collaspsing occurs as air flows over the reed, if you look at them they look like the reeds are in backwards.
I'll get a picture to show you.
Mark
Almost a pulsejet?
http://www.thegrillstoreandmore.com/ima ... 98007b.jpg
http://www.musicoutfitters.com/ethnic/bulh.htm
Notice how the reed is in the sprung open position. Air skirts in around the open reed crack creating a vacuum and exits the bottom round end leading out to the horn. It's just funny to see a reed that works "in reverse". The reed end sleeves into the bulb of the horn. The threaded end of the reed screws into the brass horn body.
http://www.musicoutfitters.com/ethnic/bulr.htm
What if
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