On an unrelated thread someone was asking about how to build some sort of airflow interrupter. Though I couldn't directly help, something he said made me think of something I'd like to try for Halloween. Take a tube and put a free rotating disk on a shaft in it. Blow air through the tube and allow the disk to rotate, much like Mick Dundee did when he was calling for Aborigines helpers. He used a flat stick on a string and swung it over his head and it produced a whirring sound. I've done the same thing and it's pretty cool. However, I don't want to sit outside in the shadows swinging a stick over my head. Rather, the airflow from the afore mentioned tube might be a pretty cool trick.
I also have a drip irrigation system in the wife's garden. Every fall I blow it down to winterize it. Quite by accident I discovered that when it's blowing down it hisses (expected), but as the air pressure drops off it starts to whistle like that of a falling bomb. Only with a couple dozen drip irrigators making the sound at the same time it sounded rather ghostly.
So what are you thinking of doing for Halloween? I know I have a new idea to mess with. Will let you know how it turns out.
I also have a drip irrigation system in the wife's garden. Every fall I blow it down to winterize it. Quite by accident I discovered that when it's blowing down it hisses (expected), but as the air pressure drops off it starts to whistle like that of a falling bomb. Only with a couple dozen drip irrigators making the sound at the same time it sounded rather ghostly.
So what are you thinking of doing for Halloween? I know I have a new idea to mess with. Will let you know how it turns out.