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4" And 6" Shells With Dragon Eggs


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#21 dangerousamateur

dangerousamateur

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Posted 16 November 2019 - 01:53 PM

@MinamotoKobayashi: Great work! What I do not understand is how you got your R-Candy fast enough to work even nozzleless. Especially the 150mm short engine. I find that one needs really good BP for those, and really good BP is MUCH faster than R-Candy. My sorbitol rockets in the past where nozzled, and they barely left the ground...

#22 MinamotoKobayashi

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Posted 17 November 2019 - 08:37 PM

Explosivecoek: the dimensions of the sticks are 1cm x 1,5cm x 125cm lenght.

 

The ways to push the r-candy rockets at the best are:

 

1. Use the classical 65/35 formula and add 1% RIO; add also 2% of 450-1000 Titanium for a nice fluffy tail.

I didn't noticed appreciable loss of thrust adding so few Titanium.

2. Found the right RIO. There are tons of different RIOs! I was lucky to found the best RIO available in the oldest grocery store of my city;

3. Granulate the propellant following my own tutorial;

4. Slightly wet the propellant: I use the classical mix 70% distilled water 30% ethyl alcohol;

5. Press the granulated propellant at 7000+ PSI (for aluminum tubes). For cardboard tubes there is the risk to deform the shape and shorten the overall lenght of the rocket, also if the walls were waxed, so it is better to lower the pressure applied (it is the classical try-and error method);

6. Dry well the rocket in a dehydratator at 70 °C for 1 hour. Redrill the hole (wetted mix should be present inside the hole). Dry again the rocket for another hour.

Do not use ventilated electric oven because the dangerous radiant heat. If You have only ventilated electric oven insulate the rocket putting aluminum foils

between the heating elements and the rocket. The foils must never touch the heating elements or the rocket body.

 

Finally, the lenght and the diameter of the hole play the most important part. Usually I push my rockets to the very limit, but if everything is made following my original specs,

the CATOs are rare. I love nozzleless rockets because they are much more tolerant compared to the nozzled ones, and create a tremendous thrust for few seconds,

that is ideal for fireworks.


Edited by MinamotoKobayashi, 17 November 2019 - 08:40 PM.





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