Delay Powder

From PyroGuide

Delay powder is a slow burning powder used in a sky rocket to allow it to reach its apogee before igniting its payload. It is usually rammed after the propellant, and the payload's fuse is ignited once the flame from the delay powder reaches it. While there is no limit to what can be used, one mix is given as a reference.

One Suitable Composition from a Skylighter.com Tutorial. Potassium nitrate 45 Charcoal 50 Dextrin 5

Reference Skylighter.com - Stinger Rocket Tutorial composition is listed after rocket cut-away illustration.