Brief:
This is a portable tracking smoke container for leaving a trail of smoke (as opposed to a puff) from any rocket it fits in.

Construction:
It is made up of the following:

• 1 piece of body tube 3 to 6 inches long, smaller than the diameter of the rockets it is intended for
• 1 unassembled two-piece plastic nose cone
• Enough Kevlar thread to make a doubled loop longer than the smoke can
• 1 snap swivel strong enough to handle the stress of ejection

This idea started as a method to put an altimeter in a rocket with no payload. That version was built also.

The length of the piece of tube used is up to you. More tube = more smoke. It just has to fit down inside your tube with the parachute.

Glue the base of the nose cone into one end of the tube. Cut the tip off the nose to make a hole you can easily squirt your tracking powder into and will let it trail out without plugging up. You may need to experiment with this before gluing this part on to get the flow you want. When have the result you want, glue the top of the nose in. Tie the cord into a loop. Run one end of the loop through the connector on the nose base and then run the rest of the cord through that loop and pull it tight. At the other end, run the end of the loop through the eye in the snap swivel. Pull through just enough to slip over to the other side of the snap swivel, making a slip knot just like on the nose base.

Flight:
Prepare your bird for flight as normal. Push the chute down and then just before putting the nose on, pour your tracking powder into the hole in the container. Place the can open end up into the body tube. Finally, clip the snap swivel to the nose or shock cord. Remember to keep the bird upright all the way to the pad and launch.

I've built and flown two with different diameters. With a 6" piece of 24mm tube and nose cone inside a 29mm bird, I can get a smoke trail of 5 or 6 seconds. A trail makes it much easier to track or at least get a prediction of descent for a high flying bird.

Summary:
PRO: If packed below chute, it can assist chute deployment. A trail is way better than a puff.

Packing it above the chute makes it less likely to dump some powder inside the rocket. You probably will end up with tracking powder on the outside of the rocket, but it wipes off easily.

Other:
For a real treat, use glitter for tracking. Think of how mylar chutes and streamers are more visible. Glitter is biodegradable (albeit slowly since it's cellophane based), non-toxic, and barely an irritant if ingested. Material safety data sheets are available for it since an RSO might ask.

Regarding the altimeter version: put the altimeter in the tube, tape the nose on instead of gluing, and pack above the chute. The rocket might need a vent hole so consult your altimeter instructions.