That temperature sensor on liner is really cool idea, I am only curious about the sensor outlet node. All the very best for hot fire test. This time the tank interfaces at both ends also looks solid.
Nice! I like the idea of using temperaturesensors on a strip pcb. What kind of percision are you expecting out of this method? And what kind of sensor are you using? I would guess an I2C sensor? :) Allso the spars in 5:11 seem to have a sharp burr. Doesn't that affect the carbon fibres under vibrations? I'm thinking of a saw like effect. Furthermore the nut looks like its tacked from just one side. Is that enough to stand upto the dynamic loads of a rocketlaunch? Congrats to your tank! Thats an important step! :) AHow are you planing on validating the 150 bar or are you going to call 1.06 good as a safety factor? :)
1. I am not sure about the type of temperature sensors we used. I would need to ask the ground systems lead. We don't need super accuracy on it though but +/- 1 degree Celsius would be fine. 2. The spars I showed in the video are actually the generation 1 spars (they are in the tank that failed). The newer version which is in the tank that worked is a single piece of aluminum which has been filed into shape (which was a ton of work but unfortunately CNC milling was just too expensive). The aluminum spar is directly threaded so no need for the sketch tacked on nut. 3. The operating pressure is 70 bar and the max pressure we reached in the test was 107 bar so we are just beyond SF 1.5. That is the requirement for testing for EUROC. The tank itself is SF 7 according to the structures team so I don't imagine it would fail (of course that assumes the welds are perfect... and that we wound a perfect pattern...)
@@ASTRABremen cool! I'm looking forward to your results with the temperatursensors! Oh shit 😅 I feel your pain with the filing 😅 but i'm sure it was worth it 👍 Ah okay i got that mixed up 👍 awesome. Thats great to have a tested tank that early before the competition 💪 great job
We will probably do that in the future... But it is unclear that we will notice the problem when just pressurizing the metal because it can't reach the high pressures that we are operating at without the Carbon Fiber overwrap. But it could at least identify a particularly bad weld I guess.
Have you considered a foam mandrel that can be dissolved out after the epoxy cures? Or a mandrel that melts at a low temperature? I suppose machinable wax is kind of expensive, though. I've heard of human powered airplanes that used carbon tubes wound over aluminum tube mandrels. The mandrels were dissolved out with an acid bath. Sounds kind of nasty, though. Is carbon better for such tanks than Kevlar would be? I've seen an SCBA tank which was wound from Kevlar. Finally, have you investigated vacuum infusion? That might save you a bit of weight.
Maybe you don't have the right equipment, but the very first time I TIG and MIG welded, I made some very decent welds. Those just look horrible. Isn't there a welder around who would be willing to donate his time to do your welds or teach you how to weld?
To be fair, I was using a TIG welding tool that was over 50 years old and I had no idea how to set it up. We do get some guidance when using now tools from the people who run the labs we work in, but sometimes we are a bit on our own, especially if we are using a tool from the last century... I am sure we will figure it out soon though. For now, we go to the professionals for the TIG welding a least.
![BLACK BAG - Official Trailer [HD] - Only in Theaters March 14](http://i.ytimg.com/vi/Du0Xp8WX_7I/mqdefault.jpg)
That bus ride with the bomb-looking tank and a bunch of equipment must have been so awkward :D
At this point, I think enough people in Bremen have seen us that they are used to it... This is a rocket town now!
Good luck guys. Just remember, it is rocket science afterall.
That temperature sensor on liner is really cool idea, I am only curious about the sensor outlet node. All the very best for hot fire test. This time the tank interfaces at both ends also looks solid.
Yes, we will see how well the idea works once we fill the tank with nitrous.
As always good quality content!
Glad you enjoyed!
@@ASTRABremenWe need a name for the engine.
Neck blocks? What pressures are you running? Is tank expansion going be an issue with hard point mounting?
Also please tell me you are not using Klima motors for ignition again .... 😅
We are......... They are 100% reliable so far.
Nice! I like the idea of using temperaturesensors on a strip pcb. What kind of percision are you expecting out of this method? And what kind of sensor are you using? I would guess an I2C sensor? :)
Allso the spars in 5:11 seem to have a sharp burr. Doesn't that affect the carbon fibres under vibrations? I'm thinking of a saw like effect. Furthermore the nut looks like its tacked from just one side. Is that enough to stand upto the dynamic loads of a rocketlaunch?
Congrats to your tank! Thats an important step! :) AHow are you planing on validating the 150 bar or are you going to call 1.06 good as a safety factor? :)
1. I am not sure about the type of temperature sensors we used. I would need to ask the ground systems lead. We don't need super accuracy on it though but +/- 1 degree Celsius would be fine.
2. The spars I showed in the video are actually the generation 1 spars (they are in the tank that failed). The newer version which is in the tank that worked is a single piece of aluminum which has been filed into shape (which was a ton of work but unfortunately CNC milling was just too expensive). The aluminum spar is directly threaded so no need for the sketch tacked on nut.
3. The operating pressure is 70 bar and the max pressure we reached in the test was 107 bar so we are just beyond SF 1.5. That is the requirement for testing for EUROC. The tank itself is SF 7 according to the structures team so I don't imagine it would fail (of course that assumes the welds are perfect... and that we wound a perfect pattern...)
@@ASTRABremen cool! I'm looking forward to your results with the temperatursensors!
Oh shit 😅 I feel your pain with the filing 😅 but i'm sure it was worth it 👍
Ah okay i got that mixed up 👍 awesome. Thats great to have a tested tank that early before the competition 💪 great job
Why not pressure test just the tank and correct welds?
We will probably do that in the future... But it is unclear that we will notice the problem when just pressurizing the metal because it can't reach the high pressures that we are operating at without the Carbon Fiber overwrap. But it could at least identify a particularly bad weld I guess.
Have you considered a foam mandrel that can be dissolved out after the epoxy cures? Or a mandrel that melts at a low temperature? I suppose machinable wax is kind of expensive, though.
I've heard of human powered airplanes that used carbon tubes wound over aluminum tube mandrels. The mandrels were dissolved out with an acid bath. Sounds kind of nasty, though.
Is carbon better for such tanks than Kevlar would be? I've seen an SCBA tank which was wound from Kevlar.
Finally, have you investigated vacuum infusion? That might save you a bit of weight.
Maybe you don't have the right equipment, but the very first time I TIG and MIG welded, I made some very decent welds. Those just look horrible. Isn't there a welder around who would be willing to donate his time to do your welds or teach you how to weld?
To be fair, I was using a TIG welding tool that was over 50 years old and I had no idea how to set it up. We do get some guidance when using now tools from the people who run the labs we work in, but sometimes we are a bit on our own, especially if we are using a tool from the last century... I am sure we will figure it out soon though. For now, we go to the professionals for the TIG welding a least.
You need to stress relieve the tank after you have it welded.
Holy that’s some terrible craftsmanship 😂 that isn’t gonna hold much
Recap video
You guys could’ve used a beer kag😂