Re: [psas-airframe] Orifices!!!
Hi guys, I'm sick and won't be coming to the meeting tonight. For what it is worth here are my thoughts: -I think we should aim for <10% measurement uncertainty. --This probably is expensive to achieve over our range of flow rates with most kinds of flow meters (though we could do more research here). --The dP tranducer has error +/- 5 psig, if we pick the larger orifice we will have 50% measurement uncertainty at the 1 lb/s flowrate. If we want to lower the uncertainty by increasing the pressure drop, then we need to factor in the added expense of the higher-pressure dP sensor (note that even the 260psi dP sensor would have ~17% error @ 1 lb/s). --Probably our best bet is to use 2 transducers in lieu of a single dP transducer. Some of the ashcroft/omega ones easily meet our requirements and we can move to a bigger pressure drop to improve accuracy. I also like this because the sensors won't be 1-offs and potentially could be recycled into other projects. Bert and/or Jacob, was there a sensor you liked for LFETS applications? If so can you send me a link to the spec sheet? --An alternate option is to relax either our range of flow rates or measurement accuracy requirements. Thoughts about this Kristin? Ad astra, Erin Schmidt On Sun, Nov 26, 2017 at 10:10 PM, Kristin Travis <theeblueorc...@gmail.com> wrote: > dP presure transducers get pretty expensive if you go above 250 psi. Maybe > a flowmeter costs less than the orifice + the dP transducer + the fittings > and tubes for the dP transducer? Or if we drill out the orifice to have a > larger hole, can we drop the dP below 250psi (assuming it's 250 psi dP > across the transducer)? > > Let's go over this on Tuesday > > On Thu, Nov 23, 2017 at 11:59 AM, Musil Mark <musilmar...@gmail.com> > wrote: > >> Ok, I will await your modified order. >> >> On Nov 23, 2017 11:27, "Erin Schmidt" <es...@pdx.edu> wrote: >> >>> The dp treasurer will not work for the range of flow rates required >>> (either the pressure is too high for the sensor, or the measurement >>> error>50%). Let's respec it. >>> >>> On Nov 22, 2017 7:14 PM, "Mark Musil" <mmu...@pdx.edu> wrote: >>> >>>> The current purchase order is attached. Nothing has been ordered. Let >>>> me know what needs changed. >>>> >>>> On Nov 22, 2017 5:04 PM, "Kristin Travis" <theeblueorc...@gmail.com> >>>> wrote: >>>> >>>>> Hi Erin, >>>>> >>>>> The dP transducer we spec-ed is this https://www.omega.com/pre >>>>> ssure/pdf/PX26.pdf >>>>> >>>>> I cc'd Mark Musil, did you order this yet Mark? >>>>> >>>>> Thanks, >>>>> Kristin >>>>> >>>>> >>>>> On Wed, Nov 22, 2017 at 4:34 PM, Erin Schmidt <es...@pdx.edu> wrote: >>>>> >>>>>> BTW have you guys ordered any of the 'general purpose' pressure >>>>>> transducers yet? I'd like to have a look at the spec. sheet. >>>>>> >>>>>> Ad astra, >>>>>> Erin Schmidt >>>>>> >>>>>> On Tue, Nov 21, 2017 at 10:13 PM, Erin Schmidt <es...@pdx.edu> wrote: >>>>>> >>>>>>> Guys, >>>>>>> I want your feedback on this orifice: Brass, 2712T47, 0.047" >>>>>>> diameter, 1/2"X1/2" NPT ($24.69) >>>>>>> *https://www.mcmaster.com/#2712t47/=1ad0hiu >>>>>>> <https://www.mcmaster.com/#2712t47/=1ad0hiu>* >>>>>>> >>>>>>> Gets us a 30 psi drop at the low end of our flow range (still not >>>>>>> sure if 30 psi is too much for flow measurement accuracy, the >>>>>>> corresponding >>>>>>> drop will be 120 psi @ 2 lb/s and 260 psi @ 3 lb/s). This implies we >>>>>>> need a maximum tank pressure of around 344 psi. If we go up to a 0.063" >>>>>>> diameter the range is a bit more reasonable (10, 35, 80 psi @ 1, 2, 3 >>>>>>> lb/s). Have we had any luck speccing the delta-p transducer yet? Knowing >>>>>>> the accuracy of the measurement will help us make a more informed >>>>>>> decision >>>>>>> about the orifice... >>>>>>> >>>>>>> >>>>>>> Ad astra, >>>>>>> Erin Schmidt >>>>>>> >>>>>>> On Tue, Nov 14, 2017 at 10:43 PM, Erin Schmidt <es...@pdx.edu> >>>>>>> wrote: >>>>>>> >>>>>>>> https://neutrium.net/fluid_flow/discharge-coefficient-for-no >>>>>>>> zzles-and-orifices/ >>>>>>>> >>>>>>>> Ad astra, >>>>>>>> Erin Schmidt >>>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>> > ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
[psas-airframe] Propulsion Class
Hi everyone, Just a reminder, there is a propulsion class today, *starting in about 10 minutes*. We'll be learning about combustion, thermochemistry and the NASA CEA program. I'll also stream it on http://psas.pdx.edu/hangout/ . Hope to see you there! Ad astra, Erin Schmidt ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
[psas-airframe] Propulsion Meeting 3.21
Hi Guys, I'm going to be busy wrapping finals this Tuesday, as I imagine many of you also are. I suggest that we cancel this week's propulsion meeting. In the meantime everyone please think about critical agenda items, and share them on the airframe team list so we can get an early start on discussion where necessary. Ad astra, Erin Schmidt ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
[psas-airframe] Propulsion Meeting
Hi everyone, This is a reminder that we're meeting *today at 6:00PM in the rocket room*. We're scheming to establish a schedule for all remaining work prior to the first LFE static test, and there is much to discuss. Hope to see you there. Ad astra, Erin Schmidt ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
Re: [psas-airframe] Meeting today @ 5:30 with David Gregory
I'm waiting on a confirmation from David. But, yes, let's plan on meeting in the rocket room. Ad astra, Erin Schmidt On Tue, Sep 6, 2016 at 2:56 PM, Asa Anderson <a...@aoptec.com> wrote: > If so, I will be there. > > > > *From:* Kyle Meeuwsen [mailto:meeuwsen.e...@gmail.com] > *Sent:* Tuesday, September 6, 2016 2:55 PM > *To:* Asa Anderson <a...@aoptec.com>; Erin Schmidt <es...@pdx.edu>; Dylan > Stephens <dste...@pdx.edu>; Matt Swigart <matt.swig...@bsigroup.com>; > Trevor Leake <le...@pdx.edu>; psas-airframe@lists.psas.pdx.edu > *Subject:* Meeting today @ 5:30 with David Gregory > > > > Hello Erin, > > > > Is the meeting still on for David today at 5:30? Should we meet in the > rocket room? > > > > Best, > > Ky;e > ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
[psas-airframe] Bob Watzlavick meeting notes
Hi Guys, Bob of Robert's Rocket Project ( http://watzlavick.com/robert/rocket/index.html) has a chat with us recently about feed system components. Here are the key takeaways: -Super cheap sintered bronze filters are available from Mcmaster Carr (98355K853) and appear to be both ethanol and LOX compatible. -Bob recommends 6-12" of isolation of pressure relief system from the vent valve/LOX tank manifold assembly (conduction path, unless a failure has occurred there should be no flow path of the LOX directly to these components). -3/8" on the main lines may be too small. There are NASA guidelines for maximum flow speed in tubes which we should follow. -Bob recommends a (valveless) full-flow quick disconnect on the LOX fill. -Bob recommends a snap-tite QD fitting on fuel fill. -It's imperative that the vent valve be cryo rated, he suggest that it be 1/2" sized. -Fill LOX from a low pressure dewer (turn off the pressure builder valve); we will want to fill w/ 30 psi or so. -Bob suggests that we use Orego globe valve for the LOX manual bleed valve. Something along the lines of http://www.ebay.com/itm/Rego-BK9454-Shut-Off-Valve-Cryogenic-1-2-FNPT-Extended-4-Stem-NEW-/142082667537?hash=item2114c97411:g:ltUAAOSwIgNXrKwZ Ad astra, Erin Schmidt ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
Re: [psas-airframe] Meet up at Hotlips at 5:45 today?
How about 5:30? (Per the posted schedule). Ad astra Erin Schmidt On Jul 12, 2016 11:16 AM, "Kyle Meeuwsen" <meeuwsen.e...@gmail.com> wrote: > Yes, I can do that at the meeting. > > Kyle > > On Tue, Jul 12, 2016 at 11:06 AM, Matt Hauer <matthew.ha...@gmail.com> > wrote: > >> I'm game. >> >> Also, Kyle, could you post the to-do text file up to git? >> >> On Tue, Jul 12, 2016 at 10:59 AM Kyle Meeuwsen <meeuwsen.e...@gmail.com> >> wrote: >> >>> Liquid Test Stand, >>> >>> You guys want to meet at hotlips at 5:45PM today prior to the meeting? >>> >>> Best, >>> Kyle >>> ___ >>> psas-airframe mailing list >>> psas-airframe@lists.psas.pdx.edu >>> http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe >>> >> > ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
Re: [psas-airframe] Meeting Today
I won't be able to make this one either. Thanks for your work on the BoM Kyle. Do you have any agenda items for folks who do make it to this one? Ad astra, Erin Schmidt On Tue, Jun 28, 2016 at 9:00 AM, Kyle Meeuwsen <meeuwsen.e...@gmail.com> wrote: > Hello Gang, > > I am sorry but I cannot make the meeting tonight. > > Updates from me though: I have almost finished the the BOM and PID all the > way down to every fitting and adapter. I hope to have it out to the group > tomorrow. I have also received good feedback from Arocket on the vent valve > for LOX and Ethanol. I just need to reed through and decipher it a bit. > > Best, > Kyle > ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
Re: [psas-airframe] Cleaned up the callouts.
Hi guys, I've pushed a jupyter notebook to the git repo to work out any remaining analysis for the feed system for this summer's static test campaign. Please add to it as you will. Just a note, the pressurant volume calculation should be correct in principle but I used some made up numbers for some of the constants. I'll fix that as soon as I can. Next thing on my todo is to calculate Cv for all valves upstream of the prop tanks. Here is the link: http://nbviewer.jupyter.org/github/psas/liquid-engine-test-stand/blob/master/feed_system_calculations.ipynb Going forward lets cc the psas.airframe list on these sorts of emails. Ad astra, Erin Schmidt On Tue, Jun 21, 2016 at 4:53 PM, Kyle Meeuwsen <meeuwsen.e...@gmail.com> wrote: > I will be there around 5:45. > > Kyle > > On Tue, Jun 21, 2016 at 3:01 PM, Erin Schmidt <es...@pdx.edu> wrote: > >> Proportion team meet at hotlips today at 5:30? >> >> Ad astra >> Erin Schmidt >> On Jun 14, 2016 10:05 AM, "Kyle Meeuwsen" <meeuwsen.e...@gmail.com> >> wrote: >> >>> Guys, >>> I will arrive at PSU later today (around 6:30). We usually meet up on >>> the 5th floor of the drop tower building. People will probably be hanging >>> around there by 5:30 or 6 PM working on random stuff. >>> >>> Asa, >>> This PID looks awesome. Thank you for your work on this. Do you want to >>> present with me tonight at the meeting? You can briefly present your PID as >>> just the final PID and I can present the schedule? >>> >>> Dylan, >>> Do you want to present the FEA and any design progress on the bracket? >>> >>> Erin, >>> Can you please add Asa's PID from the previous email, the schedule and >>> the FEA image to the slides for us for tonight? >>> >>> Thanks, >>> Kyle >>> >>> On Mon, Jun 13, 2016 at 7:53 PM, Asa Anderson <a...@aoptec.com> wrote: >>> >>>> I realized that the callouts needed to be cleaned up. >>>> >>>> See attached… >>>> >>>> >>>> >>>> -Asa >>>> >>> >>> > ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
[psas-airframe] Launch tower
Open question to the airframe team list: what seems like a reasonable upper limit to how tall we can make the launch tower. Assuming LV4 does not have active pitch/yaw stabilization it will need the TWR to be passively stabilized aerodynamically coming of the rail. I would like to model this as a constraint for the LV4 MDO project, hence the question. I'd love to hear your ideas. Ad astra, Erin Schmidt ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
Re: [psas-airframe] [PSAS] Fwd: Freezer Here!
Unfortunate news, It looks like MME is adamant that the freezer is going in the MELT lab; an electrician is coming in tomorrow to make a quote for installing the 230 A outlet. No word yet on when the actual installation would take place. Hopefully I'll have concrete details on that tomorrow. Also, some folks in the MME office asked about release forms for the Boeing donation, and that they wouldn't be able to have them signed ex post facto. Does anybody have more information about this? Ad astra, Erin Schmidt On Wed, Mar 23, 2016 at 12:26 PM, Andrew Greenberg <a...@ece.pdx.edu> wrote: > Hi Joe, > > psas-airframe is a better list for this kind of thing, not psas-team. > > > I just got an email from Dr. Lindgren in the Biology department. They > > would like us to have the stuff out of the cold room before the start of > > the term, so it's not in the way of people's experiments. > > If you could respond to Dr. Lindgren and let him know we'll have it out > by then, that would be great. > > > Is there any news on if/when we can move the freezer? > > Erin, any update on this, including use of the Capstone lab? > > URGENT: Joe or Erin, can you please email Kenny and me closeup pictures > of the outlet in the capstone lab, and of the plug on the freezer? We're > trying to figure out an adapter today. > > > When we move the rolls out of the cold rooms, it's going to be a little > > more difficult than loading them in, since they don't have their boxes... > > Sure. We'll have an open bed big pickup, so I think it'll work out. But > you're right, more is better. We'll coordinate times once we know more > about the freezer. > > Andrew > > -- > --- > Andrew Greenberg > > Electrical and Computer Engineering > Portland State University > http://www.ece.pdx.edu/ > a...@ece.pdx.edu C: 503.708.7711 > --- > ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
[psas-airframe] Thurs 2/19 Propulsion Meeting
I think I'm too swamped this week with midterms and getting ready for the NARCON presentation to be at the propulsion meeting this Thursday. I also feel like I've been endlessly rehashing the same stuff, as the composition of our group seems to change constantly with time. As right now there seems to be only ME seniors involved in the propulsion project I'm going to refocus things on that level henceforth and maintain a brisker pace moving into the future. Next time (2/26) will be on pressurization systems. I'll send out slides early next time so there is time to review beforehand and we can spend most of our time actually doing the calculations for the proposed engine. Ad astra, Erin Schmidt ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
Re: [psas-airframe] Propulsion meeting times
There doesn't seem to be much broad agreement about an earlier time on Monday or Wednesday. Perhaps you guys can use 'reply-all' if you follow up with this. I'd like to propose either Mondays at 4:00 Wednesdays at 4:00 Thursdays at 7:00 Please reply with a thumbs up or down for each these times. As I said before I would prefer an earlier meeting on Monday or Wednesday, but it might not be possible to find a time that is perfect for everyone. But let's try to move forward with a schedule that is at least doable for the majority. Also, ME capstoners please tell everyone in your group to sign up for the psas airframe list if they haven't already. Given that the design requirements for the capstones themselves depend partially on the design of the 100km rocket we should all try to stay abreast of the discussion as it unfolds. Ad astra, Erin Schmidt On Thu, Dec 18, 2014 at 12:31 PM, Adam Kiss adamkiss...@gmail.com wrote: Monday or Wednesday, anytime after 4 would work for me. On Tue, Dec 16, 2014 at 3:30 PM, Erin Schmidt es...@pdx.edu wrote: Fall term is over, long live fall term. I'm finally ready to resume propulsion meetings, but I must confess that I didn't really like how the old meetings tended to run late. I would prefer that new meetings be held earlier in the day. Formerly we met at 8:00PM on Thursdays. I am free staring at 7:00PM on Thurdays, but I'm more partial to holding earlier meetings on Mondays or Wednesdays (say starting 4 or 5). What times work for you guys for this coming term? Let's see if we can find the most optimal schedule arrangement. Our goal is to have solid design reqs for the test stand and RCS capstone teams by the end of winter term so this needs to happen soon. Ad astra, Erin Schmidt ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
[psas-airframe] Propulsion meeting times
Fall term is over, long live fall term. I'm finally ready to resume propulsion meetings, but I must confess that I didn't really like how the old meetings tended to run late. I would prefer that new meetings be held earlier in the day. Formerly we met at 8:00PM on Thursdays. I am free staring at 7:00PM on Thurdays, but I'm more partial to holding earlier meetings on Mondays or Wednesdays (say starting 4 or 5). What times work for you guys for this coming term? Let's see if we can find the most optimal schedule arrangement. Our goal is to have solid design reqs for the test stand and RCS capstone teams by the end of winter term so this needs to happen soon. Ad astra, Erin Schmidt ___ psas-airframe mailing list psas-airframe@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-airframe
