PROTOTYPE 3 AND MODELING THE IMPORTANT PARTS

My parts arrived some time ago! But sadly, some of the parts, that I needed were sold out the point I ordered :(

Last Design, WAY TO POWERFUL

When I checked my last rocket, with the inputs of the only motor I could get, I noticed something problematic… I accidently had 1 parameter wrong. The thickness of the cardboard body tube. Thats why it was weighing >1kg. I fixed it, ran a flight simulation again.. AND HOLY MOLY IT CRACKED 300 METERS -> ~984 FEET

And there are legal limits, which is why I redesigned the rocket and ordered smaller C5-7 Motors.

THE NEW DESIGN

It’s perfect. I love it. It looks beatiful. The fins. The Nose cone. Everything. Slimmer, more dynamic and it perfectly hits ~100 meters.
But again.. there is just a slight problem..

Ejection 💥

But sadly, the ejection isn’t perfect, as the parachute ejects 7s after launch. This means, after the rocket reached its apogee, it falls for a certain amount of time and accelerates.
AND IT DOES THIS TO LIKE 100KM/H -> ~62 MPH

That’s why I calculated, if the parachute and shock cord could save the rocket. And yes (hopefully).

Calculation for it

Rocket mass with motor: 0.15kg
Acceleration: 184m/s^2

F =m*a
F = 27.6 N

This means, my shock cord needs to withstand this amount of force, right after the parachute unfolded.

Shock Cords max. weight: 14.5kg
With knots: 14.5*0.5 = 7,25kg

1N ≈ 0.102 kg (102 g)
Thus:
 27.6N = ~2.814 kg

2.814kg < 7.25kg -> therefore, we're good. (as long as the parachute doesn't rip)

3D PARTS

Yes yes, the new parts.
Most of the time I spent thinking and researching about exactly these parts. I did A LOT OF IT not recording. Probably more then 5-10 hours 😭.
But thats what I came up with:

The Motor mount.

The long tube-like part is the motor mount.
It well.. Mounts the motor to the rocket. The rectangle like hole is for using a retainer clip, that I will be making out of a thin aluminium strip. The circular hole (not visible from this side of the image) is for threading through the shock cord, which will be secured using a monkeys-fist knot. The motor is printed out of PETG.

Nose Cone 🔝

I love this part. It’s the tip of the rocket.
Its made up of 2 Parts. Firstly the top part, which has 2 holes, that are both for electronics.
The hole on the side is for a camera and the hole on the bottom is for inserting the electronics into the cone. Its also for attaching:
The bottom plate. It’s secured by 2 long M3 Screws and has a hole as well for securing the shock cord.

Currently, all of the 3D parts are untested.
I’ve only printed test rings to see if they will fit inside the cardboard body tube (now using a thinner tube btw)

Yeah! Thats it for today, please follow my project :D