First Steps with Class G Rockets

What are class G rockets? In model rocket they are know as as medium power rockets. They weigth less than 1.5 kilograms and they usually measure 1 meter long. The engines used in these rockets generate a maximum impulse of 160 Ns. In spite of this, the impulse depends on the specific characteristics of the engine. With favourable conditions they may be reached 300 metres high.

This kind of rocket seems to be suitable in order to a rocket launch approachment. Because of their small size the do not fly long distances, allowing to locate the rocket easily. In this way we can observe the rocketduring all the fligth stages:

  1. Launch: the model supports the air pressure due to the engine’s acceleration. It si experimented the maximum acceleration.
  2. Rising: the propellent has given out and the rocket ascends, losing speed until the apogee.
  3. Apogee: the rocket finds himself al the point of maximum high and stars to descent because of his own weigth.
  4. Ejection: the recovery system is unfolded after the delay time.
  5. Recovery: the model descents till the ground.

The most importan part of a rocket is his engine. It generates enough impulse to rise the rocket. There are many types of engines depending on the kind of propellent or how much impulse could they generate. We can find to engines which use solid propellent:

  • Engines with black powder.
  • Composite engines. The are rechargeables.

To begin with, we are going to work with Maxi Alpha III rocket, made by Estes company. This is a pretty ligth rocket (180 grams apro.) and 80 centimeter long. The black powder engine used with this rocket generates an impulse of 20 Ns, allowing us to reach 200 meters high.

Techinical sheet:






Here it is our rocket


Rockets’ store area

Launch of a Maxi Alpha III


Summary with the activities made during the Spanish RocKetry Meeting 2014



You can find here more information about the theory of rockets:

Model Rocket Handbooks:



Rocket Engines:



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