What rocket "whistle" to use.

I got my Mimi to whistle by using a higher impulse motor (I think it was an E30-7T)

You can get rockets to whistle by fin placement too (I think the BSD Thor does this as well as the PML Endeavour)

-Aaron

Some THOR's whistle, some don't. I think I got my 3" THOR to whistle once. It depends on wind conditions, motor impulse, and how aligned or misaligned the upper and lower fins are.

It is simple.

1) You must find whistles that spin freely and actually make a loud whistle. Some are cheap and have a lot of "slop" in them, and at certain speeds will lock up and not make any sound.

2) you must have them mounted out in the moving airstream - *NOT* in the boundary layer of the rocket.

The Screaming Mimi does indeed have the whistles mounted way out in the free airstream, but they are of medium to low quality, so you are lucky to get sound out of more than one of them on any given flight.

-Fred Shecter NAR 20117

I have noticed that THORs whose upper fin trailing edge / lower fin leading edge are squared off rather than being rounded or bevelled seem to whistle more. Mine does, especially on pokey motors ;o)