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Show HN: Cygnus-X1 – A Thrust Vectoring Model Rocket Flight Computer
- jumby 6y agoIf you think this is cool, check out BPS Space on youtube
- danbr 6y agoLooks like a clone of Joe’s work. Sensors, capability, and even board layout are quite similar. Surprised there’s no mention of Joe and his “AVA” on the git.
- jcims 6y agoDefinitely reminiscent at first glance. I don’t know if/how Joe licenses any of his work or if any of this is infringing in any way so I’ll avoid that topic. I will say that I am seriously impressed with folks that are able to combine so many disciplines, especially when each domain seems to have its own set of unique hard challenges.
- polishdude20 6y agoYeah sorry, Joe's AVA was definitely an inspiration. I'm actually part of his discord channel and a lot of people there have helped me with this design.
- polishdude20 6y agoYep, that's what inspired me to make this. A lot of this stuff was directly learned about from the members of his Patreon discord channel.
- centimeter 6y agoI looked into building a vectored guided rocket several years back and remember discovering that it would land me in hot water with the ATF or some similar TLA. At what point does rocket guidance step into legally questionable territory?
- showerst 6y ago“Stability, not guidance” — its sort of like “tax avoidance, not tax evasion”. I’m not sure what the defined red lines are in the US, but most people building rockets big enough for the feds to worry about are following the model rocketry code and associated with NAR/Tripoli, so at least have access to more expertise to help follow the rules. Getting the big motors requires multiple certs from those orgs, so the system tends to be self regulating to some extent, since you can’t test your code without the hardware. I know Joe Barnard of BPS has mentioned a few times that he doesn’t release his code because the laws are unclear, and lawyers familiar with them are expensive.
- mike_d 6y agoStability and guidance are both covered, specifically "gyrostabilizers or automatic pilots and integration software therefor" per ITAR. The MCTR has similar language bit I'm too lazy to find it. This is why most rocketry hobbyists won't release airfoil designs, propellant formulas, or advanced flight control systems. The issue isn't you building a rocket big enough for the feds to care about, but the people who can build (and use) big rockets using your designs. Iran for example relies heavily on open source for its drone program.
- souprock 6y agoIt seems that sharing plans would be fine after verifying citizenship of the recipient.
- syntaxing 6y agoWhoa this is awesome, what kind of engine size do you use?
- polishdude20 6y agoHaven't put an engine into it yet but it's planned for an F15 engine
- andromeduck 6y agoI wonder if one of those hobby jets would work. Seems like there's a lot of activity in the small jet engine segment in recent years from the likes of Kratos.
- souprock 6y agoHe's planning for an F15 engine, which is another class entirely. If new, it's either the F100-PW-220/220E or the F100-PW-229. It has has a thrust of 17,800 lbf (79 kN) dry, or 29,160 lbf (129.7 kN) with afterburner. If he got the old F100-PW-100 it would be 23,930 lbf (106.4 kN).
- dpe82 6y agoI suspect he's referring to this: https://estesrockets.com/product/001650-f15-0-engines-29-mm/ https://estesrockets.com/product/001650-f15-0-engines-29-mm/
- polishdude20 6y agocorrect!
- autocorr 6y agoThat's a really clever name. It's a reference to the black hole Cyg X1 [1], which was among the first astronomical X-ray sources discovered. X-rays are (fortunately) blocked by our atmosphere, so X-ray astronomy began using sounding rockets and observations of just a few minutes. [1] https://en.wikipedia.org/wiki/Cygnus_X-1 https://en.wikipedia.org/wiki/Cygnus_X-1
- dpratt 6y agoI really hope somebody that utilizes this names their rocket ‘Rocinate’ as well.
- polishdude20 6y agoThat's my hope as well :)
- peatmoss 6y agoThe Expanse did this.
- polishdude20 6y agoHaha that and other connections as well! It's also a song by Rush of an explorer who rides his spaceship into the heart of the black hole to become the god of balance. Balance -> keeping the rocket pointed up :)
- jcims 6y agoWelp this made me realize what kind of filthy Rush casual I am. Started listening on my phone to see if I recognized it. Nope. Grab headphones and renew my sympathy for Alex Lifeson, in just about any other band he would be a beast lol.
- cubano 6y agoCheck out La Villa Strangiato next...it contains, in my quite humble opinion, the best solo Alex ever composed and performed.
- scarygliders 6y agoThe first time I witnessed a vectored model rocket, was in 1996. It was launched at the 5th Annual Scottish International Rocket Weekend, in Kelburn Country Park, Largs, Scotland. [0] I was 17 years old and a member of the Paisley Rocketeer's Society [1] - one of the oldest model rocket clubs in the world, led by the late John Stewart. Gyroc 1's vectoring was accomplished by controlling a model rocket engine by way of 2 axes controlled by a gyroscope. Subsequent Gyrocs have been made and flown. [2] (Note: the article states 1995 but the 5th IRW was in 1996 ;) ) The model rocket launched to a height of about 1-2 metres, and only managed to hover for a couple of seconds before the model rocket engine was spent, but at the time it was a glorious flight. [0] https://www.gbnet.net/orgs/staar/report.html https://www.gbnet.net/orgs/staar/report.html [1] https://www.paisley.org.uk/paisley-history/paisley-rocketeers-society-1935-2005/ https://www.paisley.org.uk/paisley-history/paisley-rocketeer... [2] http://www.ukrocketman.com/rocketry/gimbal.shtml http://www.ukrocketman.com/rocketry/gimbal.shtml
- polishdude20 6y agoI wonder how many people involved in that as kids had gone on to work at NASA and other organizations.
- ggm 6y agoDemonstrates thrust vectoring with a propellor. One of those "obvious when you think about it" smart ideas I didn't think of.
- polishdude20 6y agoYeah although the thrust given by that propellor is so much less than what the motor would give that the PID gains I've got on there won't work. I'm thinking I'll try and simulate this exact propellor setup in software with some PID gains and see if the real system works like the sim, then I'll know if that's true, I can then modify the sim and find PID values for when I attach a motor.
- reasonabl_human 6y agoWhat would you use for such a simulation? Awesome project by the way!
- polishdude20 6y agoAny programming language really. I use JavaScript with the canvas library. It's just a numerical simulation simulating forces, accelerations, velocities and positions.
- z3phyr 6y agoI really want to get into thrust vectoring model rocketry (after some experiments with solid fuel "gunpowder" based rockets). The first major challenge is procurement! I was able to get gunpowder from a friend who has contacts in a fireworks shop. Constructing it required minimal machining and was a lot of fun. Finding parts and machining timing for liquid fueled rockets is harder!
- KingOfCoders 6y agoName reminds me of the black hole film.
- mhh__ 6y agoUnder GPL-3.0 - I don't object at all but out of curiosity can you actually comply with it on a microcontroller?
- MayeulC 6y agoWhy not? As long as you distribute the software in source form and the means to compile and flash it?
- mhh__ 6y agoThe anti-tivoization clauses
- segfaultbuserr 6y agoIt's not a problem. Many microcontrollers with GPLv3 licensed firmware has been shipped with perfect GPL-compliance. Tivoization is only defined as "They can modify or execute arbitrary code, you cannot." If neither they or you can modify the end product due to technical reasons, it's not Tivoization. FSF said: > Tivoization: Some companies have created various different kinds of devices that run GPLed software, and then rigged the hardware so that they can change the software that’s running, but you cannot. If a device can run arbitrary software, it’s a general-purpose computer, and its owner should control what it does. When a device thwarts you from doing that, we call that tivoization. The anti-tivoization clause basically says "the necessary technical information and data (Installation Information) must be provided to the user, so that the user can run whatever software they want, just like the developer can", for example, if firmware update is supported, the protocol must be documented and provided to the users. If signature check is used, there must be a way to get a key or bypass it. However, if nobody can modify the system in its final form (e.g. if the firmware is in OTP ROM, if the JTAG interface has been permanently disabled), it's not Tivoization, no action is needed. Arguably, when you disable EEPROM write via an one-time fuse, it ceases to be a general-purpose computer at that moment. Thus, you can still create a product that has been completely locked down, if it has been really locked down with no backdoor to ever be unlocked again. GPL says, > Corresponding Source conveyed, and Installation Information provided, in accord with this section must be in a format that is publicly documented (and with an implementation available to the public in source code form), and must require no special password or key for unpacking, reading or copying. > If you convey an object code work under this section in, or with, or specifically for use in, a User Product, and the conveying occurs as part of a transaction in which the right of possession and use of the User Product is transferred to the recipient in perpetuity or for a fixed term (regardless of how the transaction is characterized), the Corresponding Source conveyed under this section must be accompanied by the Installation Information. But this requirement does not apply if neither you nor any third party retains the ability to install modified object code on the User Product (for example, the work has been installed in ROM).
- gorgoiler 6y agoThe propeller test rig looks fun. I spent a long time in Kerbal Space Program trying to increase delta-V by using oxygen breathing jet engine boosters. Do petrol propellers work for model rockets, to at least get a boost to a thinner atmosphere?
- deleted 6y ago[deleted]
- mkoryak 6y agoYour thrust vectoring video has about 30 seconds where nothing happens. It would be great if that interval was shortened. I know nothing about thrust or vectoring, so that's my only feedback.
- angelgonzales 6y agoWhere are the decoupling capacitors on your ICs? I don’t see them on your MCU or your sensors.