At friday got really bored at work, called it a day and went to the garage to prepare some fuel
1) Cooked another batch of RNX propellant (oh this is fun one)
2) Cooked finally a decent batch of kno3/sugar/Fe2O3 end burner fuel

After trying out different ways of cooking kno3/sugar for more than year, I believe I have finally mastered cooking that propellant type (Im talking about at least +500g batches, small ones are easy). Got most of the moisture out, packed it really well without any bubbles and cracks - whole process took again ca 6 hours. But it is worth it, propellan worked like charmed! But again I had an issue with casing... I do admit that I have not been very careful with that and again, cap failed. I know whats wrong and I will fix this as a first thing tomorrow.

As I was able to see my father at weekend, we decided to have some fun and just launch the engine casing :D And that's what happened: :D

Oh man, we had so good laugh

Sorry about the quality but we were really far away and Iphone does not really have a good zoom. But anyways, took off, quite soon cap failed and started to push the "nose" down and hit the trees and then completely blowed the cap away resulting in CATO. But as I have demonstrated, end burner works really really well, I could even say that it has way too much power. Next steps will be to to fix casing, 3d print the noze, calculate CP and CG and add proper stabilizers and off we go. I'm really getting there, coupe of months and we will have a proper kno3/sugar end burner launch.
The fuel and casing mass together was 1.2kg

BUT, recentlyI have been doing tests with RNX propellant: Epoxy Kno3 Fe2O3 Aluminium and Sulfur. Small batches worked well and burning speed matched mostly Nakkas experients. But ignition is really difficult! After couple of static "tests" got some idea how the propellant works and decided to give it a try. My father was really sceptical and actually laughed when hearing the propellant made of Epoxy, but he got really serious when we actually set it off


The noise! Oh my god, it's like real rocket launch, masssssssive noise. Again, we were quite far away and the video and the noize do not completely reflect live effect but believe me, sugar rockets are nowhere comparable with that one. Whats really impressive about this propellant is that its like 10x times easier to make it than sugar propellant, nor it is hygroscopic. After 24-30 hours it also gets rock solid!

I will complete my sugar propellant end burner project, do the proper setup and launch and then completely move to RNX propellant. By the way, I am not using brand Nakka used (really hard to get it in EU). I have other one, cheap as hell but works perfectly as you can see! But in my case, % Nakka used in hes formulas really didnt make any sense nor they worked. Propellant mixture was too liquid and after hardening really did not work. So I improvised a bit, changed formula and bingo- got the good starting point from where I can start fine tuning and testing.

What I have to improve:
1) Fine tune nozzle and core
2) Ignition is difficult, this time I used BP from gun ammunition but the amount and "kick" was too low. I need lot of pressure and heat quickly on the whole core to ignite it.

This is SO FUN!


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Electronics:
Couple of previous weeks I have spent building wireless ignition system. Transmitter and receiver, wireless signal and 12v system for resistance wire connected to pyro charge. I still need voltage converter and will try to get one in coming days. So, this will again make testing and launching much more safer as I can stay away more than 100 meters if needed. Will add more data after system completely done and tested and working! Cost of it? couple of euros