∆v of a New Year Rocket?

[markus3141]

Hey guys,

I was just wondering: Whats actually the ∆v and Isp of an average New Year Rocket?

Google feels bad and doesn't wanna tell me, so anyone have a rough idea? Could probably do some maths, but I feel kinda lazy right now

[Camacha]

Could probably do some maths, but I feel kinda lazy right now

There's your answer; do some math

[fatfluffycat]

There's your answer; do some math

eww, That's what smart people are for

Edited December 9, 2013 by fatfluffycat

[dudester28]

Here's the equation you are undoubtedly looking for.

[Mr Tegu]

Gonna need to factor in drag too, unless your party is on the moon, in which case, mind if i gatecrash?

[hugix]

I doubt maths can help here. Simple home users friendly fireworks are way to chaotic to do precise measurements on. The weight of the stick differs per rocket. The amount and strength of the black powder differs from rocket to rocket. Some rockets have a bit more of the black powder pellets that provide the sparks at the end. Some have more black powder and fly higher.

The manufacturing of fireworks isn't as precise as building a real rocket. Each piece of firework has it's own different variables and the onbly way to find out is to destroy the rocket. (And thus bringing the amount of ∆v of the rocket to 0)

[Mr Tegu]

You could get a fairly decent estimate by treating it as a projectile and using v = u +at and timing the time from launch till bang. Use -9.81 as a. If you wanted to be more accurate you could tether another one to a spring balance and measure the force produced throughout the burn, then F=ma (with respect to the mass as it changes) to get a profile for the actual value of a as it changes.

[Ravenchant]

The nose is conical, right? Find the drag coefficient of that in a table somewhere and then work with quadratic drag; as soon as you have TWR, "wet" and dry mass values of the rocket, you can write down differential equations for acceleration and speed, and probably come up with a fairly close estimate.