How does a rocket launch straight up?

[Lightsout565]

Normally, one would think that an object generating large amounts of thrust would fly all over the place with no clear direction. How does a rocket stabilize and launch perfectly straight up?

 

[Danger]

That's what stabilizer fins are for. It's very similar to an arrow or a crossbow bolt. Modern firearms use rifling in the barrel to impart spin stabilization to the projectile, but the old stuff uses feathers or such-like in order to maintain a straight line.
Some missiles have their fins deployed before launching, while others such as Tomahawks are generally fired and then stabilize themselves by fin extension while en route.

 

[turbo]

We also have to consider gyroscopic stabilization. It is possible to use GPS inputs these days, but before that system was in place, you had to use some kind of internal or external stabilization to make missiles work properly. In the case of last-ditch MAD launch capability, it was probably pretty much all internal guidance (gyros), though we might never know the details of that.

 

[Danger]

We also have to consider gyroscopic stabilization. It is possible to use GPS inputs these days, but before that system was in place, you had to use some kind of internal or external stabilization to make missiles work properly. In the case of last-ditch MAD launch capability, it was probably pretty much all internal guidance (gyros), though we might never know the details of that.

Good point, Turbo.

 

[RocketSci5KN]

The bigger rockets without fins generally have one or more gimballed engines, which under computer control, can adjust the thrust vector of the engine, which effectively steers the rocket. This technique is stable at any speed, including zero. Another method, if multiple engines are available, is to vary the thrust of opposing engines. Again, the rocket will steer in a direction dictated by the thrust difference.

 

[Danger]

The bigger rockets without fins generally have one or more gimballed engines, which under computer control, can adjust the thrust vector of the engine, which effectively steers the rocket. This technique is stable at any speed, including zero. Another method, if multiple engines are available, is to vary the thrust of opposing engines. Again, the rocket will steer in a direction dictated by the thrust difference.

That is another very good point, but I feel obliged to mention that there is a minimal size and price limitation in order to make that practical. One of my favourite home-built weapons is an 18-round 20mm rocket launcher with high-explosive armour-piercing rounds, which can be comfortably carried in a shoulder holster. While I would loved to include GPS (which didn't exist when I built this), it would not be practical.

 

[turbo]

That is another very good point, but I feel obliged to mention that there is a minimal size and price limitation in order to make that practical. One of my favourite home-built weapons is an 18-round 20mm rocket launcher with high-explosive armour-piercing rounds, which can be comfortably carried in a shoulder holster. While I would loved to include GPS (which didn't exist when I built this), it would not be practical.

I have brokered the sale of several GyroJet pistols over the years, though the ammunition is more expensive than the guns, in usable quantities. If you put your hand over the muzzle when it is fired, you might get bruised. If you are more than 20-30 feet away from the muzzle, you'd better be hiding behind a a well-built vehicle.

 

[Danger]

I have brokered the sale of several GyroJet pistols over the years, though the ammunition is more expensive than the guns, in usable quantities. If you put your hand over the muzzle when it is fired, you might get bruised. If you are more than 20-30 feet away from the muzzle, you'd better be hiding behind a a well-built vehicle.

Yeah, crap but that Gyrojet had some problems. I've always loved it in principle, but didn't buy one because of user reports. Leave it suffice to be said that my 20mm shares one very small design characteristic with the Gyrojet.