The WHISTLER! - that didn't! Part 1

Recently there has been forum posts about whistling rockets.

Rockets with split fins like the BSD THOR do whistle. I've heard the THOR whistle at N.E.F.A.R. launches. Bullpups have also been known to whistle.

Estes had their SCREAMIN' MIMI design.

It didn't whistle loud enough to be heard over the engine. There wasn't enough directed airstream to activate the whistle.

The Mimi rocket had tubular plastic "Whoopee" whistles attached to the outside edges of small fins.

You can hear a "Whoopee Whistle" HERE

Two years ago I experimented with split fins trying to get a good whistle. The WHISTLER fins had opposite and angled trailing and leading edges. My hope was to direct and split the airstream over the angled leading edge of the lower fins.

Look closely at the leading edge of the lower yellow fin. You can see the angle cut.

On the BSD THOR, the upper trailing edge and lower leading fin edges are square.

It was launched a twice with a B6-4 and C6-5. No whistle was heard.

Someone would have to build a prototype where the distance between the split fins could be adjusted.

For example, one flight with 1/4" space between the fins. On the next flight, the upper fin moved up to 5/16" between the fins. Adjustments could be made until a possible whistle is loud enough and consistent.