Issue link: https://www.e-digitaleditions.com/i/1520252
Introduction Is it possible to uild a regular-looking rocket with a flying nose cone as the upper stage? I decided to find out. Design Considerations When designing an upper stage nose cone, there are three major design consid- erations,: 1) Drag Separation 2) Static Stability of a Flying Nose Cone 3) Rear Ejection I'll take these considerations in order. First up is drag separation. Drag Separation When the nose of a rocket has a relatively large mass, the nose tends to separate from the rocket aer burnout. is happens be- cause, as the rocket starts to slow down and coast, the nose wants to keep going and may separate from the rocket early. is is called "drag separation." Fortunately, there are a few ways to prevent this. One method is by increasing the friction between the nose and body tube. Usually this can be accomplished by adding some tape around the nose shoulder. I've also found you can add a small amount of cellophane tape (two strips with a width of 1/8 in. and length of ΒΌ in.) to the outside of a rocket to keep the nose on during flight while still allowing it to separate at ejection. Many rocketeers have told me I'm wrong about putting tape on the outside of a nose, and while ordinar- ily I should command little confidence, as there's seldom proof I ever know what I'm talking about, luckily the method works if you're careful. For this project, I decided to use a burn thread to avoid drag separation. e thread keeps the stages together during boost, then at staging it burns, allowing separa- tion, as I'm illustrating in Figure 1. Burn threads are used for rocket gliders and he- licopters but I'm not aware of any rockets using them to avoid drag separation. Stability of a Flying Nose Cone Obviously I'm not the first person to in- vestigate the stability of flying nose cones. Aside from the two ancient rocketeers de- 36 MAY/JUNE 2024 SPORT ROCKETRY SECTION B-B SCALE 1 : 1 Booster Motor Sustainer Motor (motor clip not shown) Nose Weight Shock Cord Burn Thread Parachute By Doug Hillson, NAR 61624 Upper Stage Flying Nose Figure 1. A burn thread was used to prevent drag separation before staging.