# Using Side Thrusters on a missile to create an angular acceleration ### Help Support The Rocketry Forum: #### sahilsaxena

##### New Member
Assume a rocket is standing on the ground with mass = 1000 kg, and near the top of rocket we apply a force of 100 N for say 1 sec,now assume that this is sufficient to tip rocket over/start tipping over. If the rocket is mid air and accelerating at 30m/s^2, then likewise how much force would be required to tilt it pi/180rad or change its trajectory by some degree, please neglect the change of mass due to consumption of fuel because the value calculated with this assumption is going to be a a value higher than required, so that is not an issue. Will the force required mid air be the same as the force required on the ground with no accelration ?

#### dhbarr

##### Amateur Professional
We do Amateur Rocketry, not missiles or homework. However, the rate of change of the rate of change of angle of attack will greatly increase when moving.

#### boatgeek

##### Well-Known Member
A 1 MT rocket is far larger than we contemplate here. This feels an awful lot like you are asking for help with homework, and you have quite a bit of missing information. Some hints on how to proceed:

Assume a rocket is standing on the ground with mass = 1000 kg, and near the top of rocket we apply a force of 100 N for say 1 sec,now assume that this is sufficient to tip rocket over/start tipping over.
You'll want to make a free body diagram of the rocket, including how tall the rocket is, its diameter to vertical supports, and how high the center of gravity is above the ground. If the center of gravity travels horizontally past the vertical line of the furthest outboard support, it will tip over.

If the rocket is mid air and accelerating at 30m/s^2, then likewise how much force would be required to tilt it pi/180rad or change its trajectory by some degree, please neglect the change of mass due to consumption of fuel because the value calculated with this assumption is going to be a a value higher than required, so that is not an issue.
You'll again want a free body diagram. You'll also need the rotational moment of inertia in the directions you're looking for. The question is also somewhat incomplete because you are asking how much force is required to change the direction. In theory, a butterfly's flap could make the rocket rotate any number of degrees given enough time.

Will the force required mid air be the same as the force required on the ground with no accelration ?
To answer this question, you either need to make an awful lot of simplifying assumptions here or have far, far more information about dynamic stability of the rocket than you're giving.

• Steve Shannon and Nytrunner

#### jderimig

If the rocket is mid air and accelerating at 30m/s^2, then likewise how much force would be required to tilt it pi/180rad or change its trajectory by some degree,
Any lateral force greater than 0 will tilt the rocket pi/180 (eventually) or change its trajectory.

• Steve Shannon

#### jimzcatz

##### Boss, Carolina Rocket Mafia
This has no place on this forum.

#### jderimig

This has no place on this forum.
Its just physics....We can discuss physics here can't we?

• samilton17 and Titan II

#### BABAR

##### Builds Rockets for NASA
TRF Supporter
42

• Tim51 and jnmiller

#### thequick

##### Well-Known Member
There will be aerodynamic loads (acting through the center of pressure) to consider in addition to the forces and inertia when calculating the trajectory change and or rate of angular rotation.

#### PatD

##### Well-Known Member
TRF Supporter
Always the ultimate answer. #### Zeus-cat

##### Well-Known Member
If a rocket leaves Cleveland traveling at 600 mph and another rocket leaves Sand Diego traveling at... You either see where this is going or you don't.

#### PatD

##### Well-Known Member
TRF Supporter
If a rocket leaves Cleveland traveling at 600 mph and another rocket leaves Sand Diego traveling at... You either see where this is going or you don't.
There are two kinds of people in the world. Those that understand inference......