 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
| HomeDiscussion Groups General ModelsRailroadsRocketsRadio Controlled Air ModelsHelicoptersLand ModelsWater ModelsModelGeeks.com Contact UsLink To UsSearch & Site Map |
Model Forum / General / Rockets / December 2005spin vanes in the flow of nozzle gases.
I want to try this but I would like to know what temperatures I would get at the nozzle of a G size BP engine. I might need a tungsten alloy. >I want to try this but I would like to know what temperatures I would >get at the nozzle of a G size BP engine. I might need a tungsten alloy. Or graphite. That's what the V2 used. tah -- Tod A. Hilty Hilty Information Systems Do not look in the direction of the flash... Curl up in a ball as you hit the ground... CAUTION: The Mass of This Product Contains the Energy Equivalent of 85 Million Tons of TNT per Net Ounce of Weight Please replace weinerboy dot org with adelphia dot net for reply. > I want to try this but I would like to know what temperatures I would > get at the nozzle of a G size BP engine. I might need a tungsten alloy. By the time the exhaust gases have reached ambient pressure, they've cooled considerably from the combustion chamber temperature. You'd probably be fine with many stainless steel (look at the AISI 300 series - you can get a 36" by 2" strip of 304 from McMaster-Carr for under 14$ - mcmaster.com) OR you can go the innovative route and use an aluminum alloy. If the vanes have enough thermal capacity, they can stay well below their melting point. If you know the maximum burn duration of your engine, you can make some harsh thermal assumptions and figure out how thick the vanes need to be to prevent thermal compromise. No tungsten needed (it's expensive anyway). Dave I would think the blast forces would be a tougher problem than the temperature anyway. >> I want to try this but I would like to know what temperatures I would >> get at the nozzle of a G size BP engine. I might need a tungsten alloy. [quoted text clipped - 14 lines] > > Dave > I would think the blast forces would be a tougher problem than the > temperature anyway. Let's say 20% of the exhast flow is intercepted by the vanes (in reality, it's probably alot less). Worst-case scenario, the total available blast force can only be equal in magnitude to the total thrust... so for 4 vanes intercepting 20% of a 100 lb thrust, that'd be 5 lbs of "blast force" per vane. That's also assuming the vanes are 90 degrees with respect to the thrust (blocking as much of the flow as possible). Angle the vane 30 degrees from the thrust direction (more realistic), and you've decreased the blast force per vane to 2.5 lbs. Dave > > I would think the blast forces would be a tougher problem than the > > temperature anyway. [quoted text clipped - 9 lines] > > Dave Are you really ALLOWED to post this stuff?  SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring GROWTH back to consumer rocketry. Produce then publish. http://www.usrockets.com >> > I would think the blast forces would be a tougher problem than the >> > temperature anyway. [quoted text clipped - 11 lines] > >Are you really ALLOWED to post this stuff? Yes he is, but that does not make it correct. > >> > I would think the blast forces would be a tougher problem than the > >> > temperature anyway. [quoted text clipped - 13 lines] > > Yes he is, but that does not make it correct. Are you SERIOUS? Are either of you under the impression that an estimate using HIGH SCHOOL physics is providing information that someone couldn't estimate for themselves without a calculator? What I posted is useless for someone that would thinking about making something dangerous... If you disagree, then perhaps you need to report NASA to Homeland Security. Their technical reports server is loaded with far more technical reports regarding control vanes and guidance. Dave > > >> > I would think the blast forces would be a tougher problem than the > > >> > temperature anyway. [quoted text clipped - 19 lines] > SCHOOL physics is providing information that someone couldn't estimate > for themselves without a calculator? :) > What I posted is useless for > someone that would thinking about making something dangerous... If you [quoted text clipped - 3 lines] > > Dave SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring GROWTH back to consumer rocketry. Produce then publish. http://www.usrockets.com >> >> > I would think the blast forces would be a tougher problem than the >> >> > temperature anyway. [quoted text clipped - 15 lines] > >Are you SERIOUS? Seriously, this is an unmoderated newsgroup and you can post just about anything. >Are either of you under the impression that an estimate using HIGH >SCHOOL physics is providing information that someone couldn't estimate >for themselves without a calculator? I can't speak for Jerry, but your impression of HIGH SCHOOL physics is clearly different from mine. Your assumption of "someone's" capability, with or without a calculator, is interesting. > What I posted is useless for >someone that would thinking about making something dangerous... If you >disagree, then perhaps you need to report NASA to Homeland Security. >Their technical reports server is loaded with far more technical >reports regarding control vanes and guidance. I understand and I do not disagree with the sharing of your opinions. However, it would be more helpful to the originator of this thread if you would share URLs to those tech reports. And yes, your post seemed to help Roy Green's understanding. Alan >Dave > I can't speak for Jerry, but your impression of HIGH SCHOOL physics is > clearly different from mine. Your assumption of "someone's" > capability, with or without a calculator, is interesting. Using conservation of momentum, trig, and elementary multiplication and division is all I needed to derive this equation: 20% x 100lb x sin(30) /4 vanes = 2.5 lbs Do you see anything that's above high-school level? And the only reason you'd need a calculator is if you don't remember that sin(30)=1/2. > And yes, your post seemed to help Roy Green's understanding. Thank you. But do you really think a newsgroup *estimate* would be used to create something like a guided missle? A guided missle is extremely sophisticated, and you need to analyze thousands of things. Anyone using estimates from a newsgroup CERTAINLY will not be able to build one. And the whole point of my original post was to show that blast force is a non-issue, in the same way that flying through clouds made from orange juice is a non-issue. ("Hey Ahmer, forget about the orange juice cloud analysis... some guy on usenet said it was a non-issue"). Also, to enlighten you on the wealth of data out there, please see the following: "Preliminary Investigation of a Fin-Actuated Jet-Vane Control System for Stabilization of Rocket-Powered Models": http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930086425_1993086425.pdf Dave >> And yes, your post seemed to help Roy Green's understanding. > [quoted text clipped - 8 lines] >orange juice is a non-issue. ("Hey Ahmer, forget about the orange >juice cloud analysis... some guy on usenet said it was a non-issue"). I don't know why you are going on about guided missiles, orange juice clouds, etc. I do agree that it is a non-issue in the sense that using spin vanes in the flow of a BP G motor is not a very good idea, regardless of the loads on the vanes. And while nobody has yet given the temperature that was requested, you did suggest some alternative vane materials. He is most likely into AR so a better solution would be to use multiple canted nozzles rather than put spin vanes in the flow of a single nozzle. Of course he could also use Micromaxx or A10-P motors as spin motors, and develop his own spin buck program. Further, it was pointless of me to suggest that your estimate of vane loads should have been better, especially when the purpose of my reply to Jerry was that you COULD make such a reply. >Also, to enlighten you on the wealth of data out there, please see the >following: > >"Preliminary Investigation of a Fin-Actuated Jet-Vane Control System >for Stabilization of Rocket-Powered Models": >http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930086425_1993086425.pdf Thanks for sharing. Although this may not be the best report to refer to, it does provide a link to the NASA (and old NACA) reports, and he may be able to find a more helpful report. It is also one that I had not read, and one of greater interest to sport rocketry. Perhaps it will inspire a reader to do a similar R&D project. Alan >Dave > especially when the purpose of my reply to Jerry was > that you COULD make such a reply. I was under the impression that you thought my reply was immoral or unethical in the sense that I was providing information that could be used to make something harmful. Jerry asked if I was allowed to post "this stuff", which I took to mean he thought it was wrong to provide information that could be used to make something harmful. Your response to Jerry's post ("but that does not make it correct") gave me impression that you both thought my reply was immoral or unethical in that sense. I guess you were questioning the actual numbers... I think I picked the wrong week to kick coffee. Dave > > especially when the purpose of my reply to Jerry was > > that you COULD make such a reply. [quoted text clipped - 3 lines] > used to make something harmful. Jerry asked if I was allowed to post > "this stuff", It was a rhetorical question and I should invent an emoticon for how I felt, after seeing many such replies from others on rmr over the years. I have only very rarely seen non-public information posted to rmr and mostly from first hand experiences of ex-military persons on items of HISTORICAL note. There are plenty of websites that go farther into actual guided missile technology and WMD manufacture and delivery. rmr is tame by camparison. But mindlessly attacking nonetheless. > which I took to mean he thought it was wrong to provide > information that could be used to make something harmful. Your [quoted text clipped - 4 lines] > > Dave SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring GROWTH back to consumer rocketry. Produce then publish. http://www.usrockets.com > > > especially when the purpose of my reply to Jerry was > > > that you COULD make such a reply. [quoted text clipped - 6 lines] > It was a rhetorical question and I should invent an emoticon for how I > felt, after seeing many such replies from others on rmr over the years. Yeah, I should have read it when I was more alert. My resolution should be to refrain from reading newsgroups before my morning coffee and after midnight. Dave >I can't speak for Jerry, but your impression of HIGH SCHOOL physics is >clearly different from mine. Upon further reflection, I think your post might pass as a typical High School physics class hand waving argument. Alan >> I would think the blast forces would be a tougher problem than the >> temperature anyway. [quoted text clipped - 9 lines] > > Dave Now that you explain it that way, I have to slap my head and go, "Doh!" You maybe right about the stainless but it would be nice if someone had some kind of table on nozzle temperatures for BP engines. I couldn't find one on the internet. It's nice enough, but what keeps it going during the coast phase, which is typically most of the ascent.? > I want to try this but I would like to know what temperatures I would > get at the nozzle of a G size BP engine. I might need a tungsten alloy. >It's nice enough, but what keeps it going during the >coast phase, which is typically most of the ascent.? Hmmm... Momentum? I mean, once a rifle bullet leaves the barrel, there's nothing that continutes to physically impart a spin, but the bullet keeps spinning, right? Interesting thread for a switch... <g> tah -- Tod A. Hilty Hilty Information Systems Do not look in the direction of the flash... Curl up in a ball as you hit the ground... CAUTION: The Mass of This Product Contains the Energy Equivalent of 85 Million Tons of TNT per Net Ounce of Weight Please replace weinerboy dot org with adelphia dot net for reply. > It's nice enough, but what keeps it going during the > coast phase, which is typically most of the ascent.? It's already spinning at that point. > > I want to try this but I would like to know what temperatures I would > > get at the nozzle of a G size BP engine. I might need a tungsten alloy. SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring GROWTH back to consumer rocketry. Produce then publish. http://www.usrockets.com You might want to do a web search for "Hale rocket". One is http://www.nasm.si.edu/research/dsh/artifacts/RM-Hale24pdr.htm This one http://www.authentic-campaigner.com/forum/showthread.php?t=101 has interesting information. Hale pioneered operational finless artillery rockets in the 1840s. The easiest thing to do would be to cant a cluster of BP motors. > I want to try this but I would like to know what temperatures I would > get at the nozzle of a G size BP engine. I might need a tungsten alloy. SignatureWill Marchant, NAR 13356, Tripoli 10125 L3 kc6rol@amsat.org http://www.spaceflightsoftware.com/will/ > You might want to do a web search for "Hale rocket". One is > http://www.nasm.si.edu/research/dsh/artifacts/RM-Hale24pdr.htm [quoted text clipped - 3 lines] > > The easiest thing to do would be to cant a cluster of BP motors. That's what Kline did (and I published) in the early 80's. > > I want to try this but I would like to know what temperatures I would > > get at the nozzle of a G size BP engine. I might need a tungsten alloy. SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring GROWTH back to consumer rocketry. Produce then publish. http://www.usrockets.com after reading this thread, it got me wondering if you had a long thrust motor, say like a E6 or F10, and the thrust was directed through a rotor, such that the thrust made the rotor spin and create lift from the rotor spinning..... sorta like a reverse roton type vehicle... with the rotor assembly at the base..? the rotor would be sorta like a ring tail below the motor...... shockie B) >I want to try this but I would like to know what temperatures I would > get at the nozzle of a G size BP engine. I might need a tungsten alloy. A pusher turbofan? The monocopters might be a cousin to that concept... > after reading this thread, it got me wondering if you had a long thrust > motor, say like a E6 or F10, and the thrust was directed through a [quoted text clipped - 5 lines] > > shockie B) SignatureWill Marchant, NAR 13356, Tripoli 10125 L3 kc6rol@amsat.org http://www.spaceflightsoftware.com/will/ I wonder if there is anyway(I'm sure you eggheads out there know) to determine how much lift would be produced thru such rocket powered pusher fan? How fast would the rotation be? It seems to me that the combination of the thrust + lift generation would be enough to get the thing off the ground? as far as material, perhaps the actual part that is in the rocket exhaust flow could be made from the same material used by the AT nozzles or that new super plastic casing material used on the AT Limited used rockets? It would last X number of flights and you would replace it ? shockie B) >A pusher turbofan? The monocopters might be a cousin to that concept... > [quoted text clipped - 7 lines] >> >> shockie B) > I wonder if there is anyway(I'm sure you eggheads out there know) to > determine how much lift would be produced thru such rocket powered > pusher fan? How fast would the rotation be? It seems to me that the > combination of the thrust + lift generation would be enough to get the > thing off the ground? While something like that might be plausible, you're going to lose altitude -- you're losing energy to friction in the bearings. Something like that which can actually stand up to the motor exhaust also isn't going to be cheap.... -Kevin I am glad that I got some of you thinking about my question, A second question about the friction of the vains. Is it more than the total friction of fins? |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.