Re: [PSAS] Airframe mfg. training
Take Video!! On Mon, Jun 2, 2014 at 8:43 PM, Samuel Arnold samuel.k.arn...@gmail.com wrote: Calling all PSAS folks, Very last minute notice, I know, but if anyone is willing and able to show up to EB480 tomorrow from 8am-10am, we will be demoing a start-to-finish carbon module layup. We will be doing the same on Wednesday morning at 10am, which would be a great time for people who saw the demo to get some hands-on training. If you can't make it tomorrow or Wednesday, we will be doing one additional module layup next Thursday, time undecided. Hope to see a few people there! Sam Arnold ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists. ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.
Re: [PSAS] Launch Date
I must have tuned out during the discussion. Last I heard we were still thinking June. I have stuff going on the 16-17 and 23-24 weekends. Is there any way we can use the wiki/calendar to put up people's conflicts? Dan Last week we talked about trying to launch mid July in Brothers. To summarize: We would love to launch again soon. We are not ready to fly a 6DOF rocket yet, but we are desperate to finally fly the flight computer with the GFEs and sensors and new patch antennas/802.11a. We also want to launch as soon as possible so we have time to think about another launch later in the fall. To that end, here are the dates of the weekends in July with a couple of notes. Everyone should look at their own calendars and figure out what would and wouldn't work and be ready to discuss an official launch date this Tuesday (the 10th). - 9-10 - 16-17 - 23-24 - This is an O-Rock launch date. And OSCON is 25th-29th - 30-31 If you can't make in Tuesday and have strong opinions about when we should launch send an email so we know what you think. Thanks, -Nathan ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.
Re: [PSAS] New room for Saturday meeting
Dave's not available tomorrow, and neither is Marius or Rob, and Chris is probably tied up as well. Jeremy and I were thinking about meeting up to discuss our project, but I don't have any controls stuff to go over tomorrow because I'd rather wait until the whole crew is present. So, If Jeremy is up for it, I'll be meeting up with him. Otherwise, I wont be coming into Portland Tomorrow. I'll check email when I get up in the morning. ~D Quoting Andrew Louie aloui...@gmail.com: I wasn't able to get access to the room in time in time. Are we going to meet at the PSBA tomorrow? On 3/4/11, Jeremy Booth jboo...@gmail.com wrote: Andrew: Probably a good thing for you to look into. I understand the room is part of the CS department. Marius: Since we are starting to have presentations on various topics at the Tuesday general meetings, maybe you could work with someone to arrange an intro to Kalman Filters on a Tuesday? It could be a good primer if we ever do get an outside speaker to present on Kalman Filters, and you'd get to help set the time, ensuring it works with your schedule. On Fri, Mar 4, 2011 at 11:39 AM, Andrew Louie aloui...@gmail.com wrote: how hard would it be for me to get badge access to 86-01? i have access to the building and labs. On 3/3/11, Jeremy Booth jboo...@gmail.com wrote: I haven't reserved anything, but I'll try to grab 86-01. I don't know that we have badge access to 86-01, so that's a consideration, but I'll make arrangements for this upcoming Saturday. I will likely not be available the next Saturday. I'll try to reserve the room, but I won't be available to get people in if we don't have badge access. We've generally met in 150 or at the PSBA. Side note: I picked up the 2 wandering posters, and have them in my office. On Thu, Mar 3, 2011 at 8:00 PM, Jamey Sharp ja...@minilop.net wrote: On Thu, Mar 3, 2011 at 7:38 PM, Andrew Louie aloui...@gmail.com wrote: Do we have the new room reserved for Saturday? If you mean FAB 86-01, Josh and I didn't reserve it for any time other than Tuesdays. I'd bet nobody else reserves it on weekends, so you could just show up there and take over until somebody tells you to stop. Or you could talk to department staff to officially reserve it. What space have you been using for the control theory class, and what time have you been meeting? Jamey ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists. ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists. ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.
Re: [PSAS] meeting tonight, including geometry/physics discussion
Last week Ben and I chatted about taking an hour of the regular meetings to explore rocket physics and, at his request, geometry topics---first up, quaternions. So let's try that tonight. During tonight's regular weekly meeting, from 8pm to 9pm anyone who's interested is invited to chat about rocket physics: how physicists model the forces on a rocket in the abstract, and how a practical computer model of those forces should work. Not trying to be nit-picky, but this has been bugging me for a while. I'll see if I can get my point accross without over-stressing semantics. One doesn't learn about algorithms by studying science; That's too broad. Instead, *computer science* might make more sense. Similarly, I think what you want to know about isn't Physics (study of motion, energy, forces, matter, and spacetime), but rather Dynamics (study of forces that cause motion) and Kinematics (study of motion without regard to source of forces). I suspect that the use of the term Physics comes from the term physics engine which started some years ago associated with computer games. I guess we *could* talk about relativity and mass to energy conversions, but it has little practical use for us right now :) I took some time last week to wrap my head around quaternions so I'm prepared to discuss what they are, why you want to use them in practical physics models, and how the important operations on them work. Nice. If we have time, I'd like to follow that up with discussion of how to implement forces that cause rotation in rockets. Several people in PSAS have been trying to explain this stuff to me over a period of years and I'm hoping to get some of it to stick, preferably in the form of executable code. This probably isn't a 1-2 hour discussion... Others have spent ~40 hours on it so far. We'll see. ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.
Re: [PSAS] $5000 prize for 100,000 foot flight
Quoting Nathan Bergey nat...@psas.pdx.edu: Yes, I think the main goal is to get people to think about GPS on rockets. Even if we don't make an attempt this should be fun to watch. More (selfishly) importantly I've been invited on the Evadot podcast tomorrow morning to be an expert pundit of sorts about the contest and what is hard about it, what's easy, etc. Anyone have thoughts about it? Is it a good idea? Is it easy? It's not trivial, but it can be done. The hard part is tracking the *rate* that the Doppler-affected satellite signal frequency changes. If you build a GPS that can track (the frequency change) that fast, it becomes susceptible to noise. This can be greatly alleviated by tightly coupling the GPS and INS sensors (+ details). How long will it take for someone to win? GPS units capable of high dynamics already exist. If someone that has one knows a rocket guy, problem solved. Hopefully I have my facts straight about GPS (yes I know about the ITAR or vs and in the cutoff conditions). Anything else relevant? Why not just fly an OEM board? OEM's have a tracking loop (google Costas loop) typically with a 1Hz bandwidth (source: a GPS INS book I have. It's at home at the moment). Some OEM units can change the loop bandwidth to something higher, but with poorer accuracy and greater likelihood of loosing the satellite lock. The result is this: if the GPS accelerates (relative to the satellite) above a certain rate (some GPS OEMs advertise 4 g's) the correlator cannot change the carrier tracking frequency fast enough to keep up, so the signal lock is lost. Another approach is to adapt the rocket to work with the GPS. This would get you the tracking, but not necessarily the altitude unless you can unlock the GPS (ITAR restriction). The OS GPS or GPL/GPS could really shine here. I'd say one could do this with a 2 stage rocket using a slow first stage, a slow second stage, and long launch rail. The key is to keep the OEM GPS acceleration under 4 G's the whole way. Hybrids might have an advantage here with long slow burns. I'm getting on the aRocket list now. Super annoying that it's closed. -Nathan On Mon, Feb 28, 2011 at 12:05 PM, Jamey Sharp ja...@minilop.net wrote: On Mon, Feb 28, 2011 at 9:57 AM, Nathan Bergey nat...@psas.pdx.edu wrote: http://www.rocketryplanet.com/index.php?option=com_contenttask=viewid=3542Itemid=29 100,000 ft is not even space, only a mere 30 km. Note the requirement of having GPS. Something we should already know how to do. Note the requirement amounts to still getting data from the GPS receiver above 100k feet. ITAR limits export of GPS receivers designed for producing navigation results above 60,000 feet altitude and at 1,000 knots velocity or greater, but as I recall, PSAS found that 1) American GPS makers don't want to build commercial receivers that they can't export, and 2) they treat the restriction as an or. So maybe the real point of this challenge is to demonstrate an amateur GPS receiver that works well above 60k feet? I wish the arocket list archives weren't closed. I'd like to see the original challenge without having to subscribe. Also note the prize is now almost meme-compliant, at $9000. Somebody should throw in another dollar. Jamey ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.
Re: [PSAS] $5000 prize for 100,000 foot flight
Quoting Keith Packard kei...@keithp.com: On Mon, 28 Feb 2011 15:05:37 -0800, I kirk...@pdx.edu wrote: Quoting Nathan Bergey nat...@psas.pdx.edu: Yes, I think the main goal is to get people to think about GPS on rockets. Even if we don't make an attempt this should be fun to watch. More (selfishly) importantly I've been invited on the Evadot podcast tomorrow morning to be an expert pundit of sorts about the contest and what is hard about it, what's easy, etc. Anyone have thoughts about it? Is it a good idea? Is it easy? It's not trivial, but it can be done. The hard part is tracking the *rate* that the Doppler-affected satellite signal frequency changes. If you build a GPS that can track (the frequency change) that fast, it becomes susceptible to noise. This can be greatly alleviated by tightly coupling the GPS and INS sensors (+ details). How long will it take for someone to win? GPS units capable of high dynamics already exist. If someone that has one knows a rocket guy, problem solved. Tracking the max altitude doesn't require high dynamic response; rockets tend to have low acceleration outside of the boost phase. There are lots of commercial GPS units capable of accurately tracking rocket position during coast, apogee and descent. The Trimble units are often used for this altitude. In fact, the new TRA altitude record rules for flights above 40k' require use of one of these in place of a barometric altimeter. I guess that's true... re-reading the challenge, the point is the 100,000 ft, not the GPS tracking. OEM's have a tracking loop (google Costas loop) typically with a 1Hz bandwidth (source: a GPS INS book I have. It's at home at the moment). Some OEM units can change the loop bandwidth to something higher, but with poorer accuracy and greater likelihood of loosing the satellite lock. The result is this: if the GPS accelerates (relative to the satellite) above a certain rate (some GPS OEMs advertise 4 g's) the correlator cannot change the carrier tracking frequency fast enough to keep up, so the signal lock is lost. Right, you lose the signal during boost, but rapidly re-acquire it after the motor burns out. The GPS in TeleMetrum loses lock under boost, but usually re-locks within a few seconds of motor burnout. It's problem is not the tracking loop low-pass filter, but the Kalman filter post-processing the raw GPS coordinates into the displayed values. That shows a huge lag, which you'd expect if the model error co-variance values were very small. I'd be happy enough to be able to change the Kalman filter values and not mess with the tracking loop filter; I'm not trying to steer. Huh? I'm pretty sure the tracking loop is causing the GPS to lose lock. Especially in your rockets (with your more-reasonable-than-PSAS mass fractions)! I'd agree that one could build a KF to track position during that time, but from what I've read on tracking correlators, IMHO the loop filter is never going to keep up with your 20+g rockets on boost. So... if this is a height competition, I would think that the sponsor would provide the GPS... Mostly because folks like us can produce a GPS log that clearly indicates 100,000 ft from my Liberty 4 ;) In fact, I'd bet Dave can do it with 2 lines of PERL. This is actually doable. Too bad we're broke... ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.
Re: [PSAS] youtube page
If the intent is to increase traffic, can we add some keywords like 'high power amateur rocketry' to the videos? I think we'd get a lot more hits. Quoting Nathan Bergey nathan.ber...@gmail.com: Fixed. On Wed, Feb 16, 2011 at 6:02 PM, Jeremy Booth jboo...@gmail.com wrote: I've been finding that directing outside folks to our youtube page seems get them pretty excited about the project. It looks like sometime recently some videos were switched around, and now our main video On Board LV2.3 with Roll Stabilization states it was removed by the user but I think it just got swapped with a new version of the same video. Could we get something current and cool to show up on the default page ( http://www.youtube.com/user/PSASRockets )? -Jeremy ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists. ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.
Re: [PSAS] Fwd: staging designs, code inspection
the code is aero model independent: plug in stages and delta v for each stage, isp and fif, and it spits back masses. Aero modeling should inform delta v apportioning. delta v for leo is like 7500 (?) m/s, so there's a fat ol' margin in those examples. I'd like to discuss aero modeling at the next meeting (what it gets us, what we can engineer around, extreme values, max q and whatnot. Yes, aero, indeed. Realistically, I don't think we want to move through the atmosphere at 3000 m/s (need max q figures). Further, we'll likely find (in simulation) that trying to do so is less than optimal in terms of fuel consumption ;) I have some questions about masses as defined as well. If the proposed numbers mean anything, I'm not sure our final mass can be 1.22 kg. We need weight of last stage tanks, motor(s), etc. with the 1kg cube-sat. On 1/31/11, David Harris dharris...@gmail.com wrote: Hi Ben, What aero model are you using and how are you calculating the gravity turn and angle of attack losses? Or at this point are you just adding some margin to the delta v target figure and just approximating? David On Sun, Jan 30, 2011 at 6:03 PM, Benjamin Kaplin bkap...@pdx.edu wrote: Ex: - m_i1 Mass of 1st stage only, including fuel - m_f2 Mass of 2nd stage only, excluding fuel This comment pointed out to me that the script was really only useful for designing a particular stage. So, to provide a more general tool, I rewrote the script. It should be a lot more user-friendly now. It allows for cool things like specifying the supportmass/fuelmass ratio on a per-stage basis. Enjoy! ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists. ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists. ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.
Re: [PSAS] Recent changes
Quoting Josh Triplett j...@joshtriplett.org: On Sat, Jul 24, 2010 at 08:08:17AM -0700, I wrote: Is the 'recent changes' page broken on the wiki? http://psas.pdx.edu/recentchanges/ I thought I made some updates, but they don't show? I just edited the sandbox, and the edit shows up on the recentchanges page. So, it *seems* to work. Also, I don't see any recent edits from you in gitweb either (http://git.psas.pdx.edu/?p=wiki.git;a=shortlog). So, either you didn't make any updates, or something *else* broke and lost your edits. I suspect that it got fixed. Looking at the history page: http://git.psas.pdx.edu/?p=wiki.git;a=history;f=trackmaster3000.mdwn What did you edit, and do the changes you made appear in the wiki? I added 'Design Concepts' and other stuff to the page, but the update didn't show in recent changes. The other stuff is not in the history either. Later, when Joe fixed the uncommitted stuff, things that were added changed some of my additions. No worries, as long as it's working now. ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.
[PSAS] Recent changes
Is the 'recent changes' page broken on the wiki? http://psas.pdx.edu/recentchanges/ I thought I made some updates, but they don't show? ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.
Re: [PSAS] Lost 1/8th inch torsion rod
I looked outside the plastic tubs. I don't think it's there. The tubs are only ~2ft on the diagonal. Too small i think. Well, thanks for looking, anyway. I thought someone (maybe Dave?) had bigger tubs. The rod would have been 36 when new, so shorter with some sort of end treatment. Does the missing rod have any distinguishing characteristics? Only that I calibrated it with equipment that I can no longer access. Oh, yeah, and it has a device made to connect to the motor fairing. My calibration idea is to take something geometrically simple with similar inertial moment (e.g. rod) and try it 1st. Yes, that will work, but when? :) Dan ___ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.
