Acceleration = Net Force Acting on Rocket / Mass of Rocket
Net Force = Thrust of rocket - weight - drag
In the above equation is thrust of rocket equivalent to average thrust?
In the case of a cluster, would you add or multiply the thrust of the rocket( average thrust of each motor?) x number of motors in the cluster?
example avg thrust = 10.21 newtons per motor and you have 7 motors
avg thrust = 71.47 Newtons?
tia
shockie B)
no
yes
You CAN estimate the average net force at any time by using the averages for everything, but it will only be an estimate and may not even be a good one at that - SWAG may be a better word than estimate. So, strictly speaking, no, you cannot use the average thrust in that equation. Every term in the equation has a time dependance.
The thrust usually has a peak then a rapid decline. The weight drops as the propellant burns and/or stages drop. The drag changes drasticly with speed and/or as stages drop.
I developed a spreadsheet to do some estimates of these quantities over time to do altitude estimation, but found that it was easier to use wRASP - especially because of the motor database. It hides a lot of the details but reports the pieces I needed.
This is correct. 2 x C6 is equivalent to a D12 (not necessarily Estes D12),
3 x C6 would be an E18, although a fairly low power E, it would have twice the average thrust of an E9.(Again wRASP handles even complex clusters).
Hope this helps.
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