Warning: Translated using Google-Translate, so it can turn out funny!

Something the activity of the participants (fifty teams!) decreased to almost zero.

Therefore,

**in order to bring revitalization**, I present my project, which is located somewhere in the middle of the road.

And I won’t leave him!

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This is only about the mechanics of flight, not about construction, control, sensors, electronics.

From the very beginning, it was assumed that one should not try to use something exotic (nuclear energy, anti-gravity, telekinesis).

It must be:

Primitive multistage rocket.

Primitive solid fuel engines.

Primitive fuel.

This will not give a large ratio of the payload mass to the launch mass of the rocket, but it will free from the development of new technologies.

According to preliminary estimates, a rocket with a launch mass of about 10 kilograms was needed to put 100 grams into orbit.

For such a small rocket, compared with large rockets, atmospheric resistance is of great importance.

And there is an optimal speed at which fuel consumption will be minimal.

If we assume that the resistance is proportional to the square of the speed and Cd is constant, then the optimal speed it is when the weight of the rocket is equal to the force of air resistance:

m * g = Cd * rho * S * v^2 / 2

For a small rocket (m = 10 kilograms, diameter 80 mm - S = 0.005 m2, sea level - rho = 1.2, Cd = 0.4), the optimal speed is approximately this:

v = sqrt(10 * 9.81 * 2 / (0.4 * 1.2 * 0.005)) = 286 m/s

So the rocket must first quickly accelerate to the optimum speed;

then maintain optimal speed in accordance with the density of air and the current weight of the rocket;

while you still have to limit the speed (not higher than 800 m/s) so that the surface of the rocket does not overheat from friction;

and only when the atmosphere is over, only then can rocket accelerate to the speed necessary to reach the orbit.

Large rockets do not have this problem, since they have an optimal speed 4 ... 7 times greater than that of a small one, and they simply do not have time to accelerate to it, and the atmosphere is already ending.

And so their engine may always work with constant thrust.

A small rocket with solid propellant engines is unable to constantly maintain optimal speed.

1. The thrust of a solid fuel engine is difficult to regulate;

2. It is impossible to make a small efficient solid fuel engine that runs longer than a few seconds.

The solution is this: many small engines runs for a short time, but they turn on alternately with long pauses.

The speed of the rocket will then fluctuate around optimal.

It turns out something like this:

The first stage accelerates the rocket above the optimum speed (500 ... 700 m/s).

In the pause the speed of the rocket gradually decreases, the height increases, the density of air decreases.

The next stage is turned on, which again accelerates rocket above the optimum (800 ... 900 m/s).

...

The fourth stage at an altitude of about 40 km accelerates rocket to a speed of about 3 km/s, while air resistance drops rapidly and further the rocket flies along an inclined trajectory to an altitude of 110 km.

At this altitude, aerodynamic heating becomes negligible and the fairing is jettison.

The fifth stage is turned on, after that the rocket flies along the trajectory with a maximum height of 350 km.

At the upper point, the last step is turned on, and rocket accelerates to the orbit speed.