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Everything posted by totalitor

  1. Welcome to follow small rocket engine testing and rocket building on my youtube channel. Any suggestions to get more thrust or saving weight on rocket are welcome! Check it out.
  2. Yes better to be safe than sorry. In my tests I am 10 m away behind 15 cm thick wood and still I look rocket engine from mirror. It is nice to see what happen when you are testing but you sure look many times videos after tests. That is more important to analyze what happend during test. Good luck to your next version. I have collected parts to my rocket, I am planning if I can get it to fly next year. Now I have 3500 grams together including engine, pressure regulators, fuel. gaseous oxygen and other sfuff. Not including stability system and recovery system. Best thrust is so far 3400 grams so there is still work - this rocket can not fly yet. Cutting weight is important but I think I have done everything I can. Ok, I have "not-so-safe-system" weight 3300 grams but there is no check valves. I am hoping to get more thrust with more pressure. Next real test begin when spring arrives - on May I think.
  3. Nice work! I think O/F ratio is good, not too much fuel. I think my engine is more fuel rich. And your engine has 20 times more thrust. Great!
  4. Average thrust 41,6 N? Is that right? TWR=33? Sounds incredible. Use more cameras when you are testing. This IS science!
  5. I think creator of this post have gave up, for many reasons I think. But he inspired me and I kept going. Now I have a small working rocket engine and next year I try to build a flying rocket. Hopefully. ap0r - are you still there?
  6. New engine RUD-12, new test. Better injector, does it increase thrust?
  7. New engine: RUD-11 with regenerative AND film cooling. How much film cooling eats thrust? Answer: a lot. Videos here:
  8. New test today. More pressure - more thrust? Look what happened. Same engine, same test platform. Thrust in earlier test 29 N (3 kg)
  9. Not quite. Isp=F/W total. If I assume O/F ratio was 1 then W total=2*0,038 lb/s=0,076 lb/s So Isp=6,61/0,076=87. That is bad. I try to raise combustion chamber pressure next time.
  10. I installed a thrust measurement system and did two test run with bigger fuel tank. Thrust is 29 N (3 kg). I expected more but this engine may have low isp or there is not enough pressure in combustion chamber. 11 seconds burning time with 190 grams of fuel. Engine weight is 180 grams (without any fittings) so TWR=16,7. Fuel is alcohol 70 % water 30 %. Videos here (RUD-10 test 9 and RUD-10 test10).
  11. Great day today! I test fired my homemade rocket engine four times and it is still alive. My goal is to have total 10 seconds thrust without melting. Last run no. 8 was very good. Tank wasn't full becouse I ran out fuel mixture but still I got a record 7 seconds. After test the engine wasn't too hot, I think cooling works well (sure, it doesn't melt...) Here are videos:
  12. Yes I have to design thrust measuring system. Then I know better.
  13. What is the best test run? 2-3 or number 4? Mach diamonds looks nice but is there too little fuel and so more temperature in combustion chamber?
  14. Ok to be clear: fuel is a mixture which contains 80 % alcohol and 20 % water. Better?
  15. I have been two years designing and building a small rocket engine. Now I've switched fuel from gasoline to 80% alcohol. I think I got it now. Four test today with same cooled engine, no melting. Test 1 - too much fuel. The engine was almost cool after test. No significant thrust. Test 2 - less pressure for fuel, good and stable combustion. There was thrust, 300 g metal plate moved (look at the video). Hot engine after test. Test 3 - same pressure, more fuel in tank. Test 4 - more pressure for fuel and oxygen, mach diamonds visible! I am not sure if this engine can run longer without melting becouse it seems I have too little tank for fuel. Cannot run longer until I change it. What do you think?
  16. Hi! New test coming, this time with cooled rocket engine. I am using gaseous oxygen and alcohol-water (about 80 % alcohol). I am planning to do at first only few second firing but I have two ways to do that 1. Fill propellant tank full and count seconds and then close all valves. In cooling jacket there remains propellant. 2. Fill propellant tank only a little and let it run empty. Nitrogen purges system after that. Which way is better to engine survive? I look videos after test and judge should there be more or less oxygen. Granted, engine meltdown is highly propable.
  17. More testing! Uncooled 4,5 kg rocket engine ignition today. Meltdown yes but how fast? Look video. Pictures: VIdeo:
  18. In Iron Sky The Coming race: at the end they head from moon to Mars. Their ship is so slow it takes 100 years to travel. Yet they were able to ascent to orbit, so TWR was not so bad. What kind of trajectory they have to Mars? I don't get it.
  19. Is there Israeli moon lander onboard? Should launch in february.
  20. Nice work! Without failures you don't learn. It is very rewarding to think and design all systems. Food for brains. Remember to take videos from many angle because everything happens so fast when an engine finally start. Take care when you ignite, remember it could explode.
  21. Today to Mars (well, not quite) and tomorrow to Spain. Nice.
  22. There were a campaign few years ago to collect names of people and send them with probe to Mars. Is that still valid?
  23. "Correct me if I'm wrong, but whilst that would increase flow speed (according to Bernoulli's equation) doesn't that actually decrease mass flow rate? It seems a little counterintuitive that a smaller cooling volume should correspond to a higher rate of cooling. " I am not sure if I can make cooling work like this but I will try. I liked that idea of using rods inside the engine but that is adding extra mass and I want to make engine as light as I could. So now I am planning to use aluminium tubes and electro etch channels to inner tube. First test of etching were good. Steel is easy, copper is not and aluminium is easy too. Aluminium rocket engine? Sounds crazy but it has been done. Check this out. And if I give up using gasoline and try 75% alcohol flame temperature would decrease about 600 C. But then I need more fuel to achieve same thrust. More mass. If I can make this motor working I want also to make a flying rocket some day.
  24. That also but the main reason is decrease cooling volume and thus increase coolant flow speed. It is still not enough yet.