Talk:Solid-propellant rocket

message: I changed the performance numbers listed for solid / Lox-RP1 / Lox-LH2 engines.  The new data reflect theoretical performance numbers, in s, for standard operating conditions (1000 psi chamber, 14.7 psi exit).  These are the numbers given by Sutton in Rocket Propulsion Elements, 7th ed, pp. 188-189.  The old numbers reflected a mix of sea level / vacuum Isp, which is misleading at the least. Evand 22:43, 21 Apr 2005 (UTC)
thread_title:  Isp 

message: Is there any solid rocket fuels handy at home. 
How to determine a fuel for a rocket.
: There are a number of rocket propellants accessible to the amateur rocketeer.  However, it should be remembered that engaging in rocketry safely requires care, knowledge, and a respect for the energies involved at all steps.  Probably the most accessible propellant is one based on sorbitol and potassium nitrate, often referred to as rocket candy.  It is related to the original candy propellant, sucrose / potassium nitrate, but easier and safer to work with. Evand 20:49, 27 August 2006 (UTC)
replies: text:  Thermite, while not made from household materials, is made from VERY easily-obtained materials (aluminum powder and iron oxide powder).  These two are actually two of the components of the Space Shuttle Solid Rocket Booster. 76.180.49.69 17:23, 13 August 2007 (UTC)
replies: text:  The oft-repeated assertion that there is thermite in the SSRBs is perhaps technically true, but misleading.  Thermite is 25% Al, 75% Fe2O3; the SSRBs contain 16% aluminum and 0.4% iron oxide.  The aluminum is present to add energy by burning with the oxygen from the AP.  The iron oxide is present not as a source of oxygen (as it is in thermite) but as a catalyst to modify the burn rate.  While the iron does end up donating its oxygen, the fact that this is not the primary purpose should be obvious from the fact that AP has a higher oxygen content in a higher energy form.  Most solid propellants include some quantity of burn rate modifiers, which work together with grain geometry and casing dimensions to provide the thrust curve required by the mission in question. Evand (talk) 15:52, 26 March 2009 (UTC)
thread_title:  Rocket fuel 

message: This article in the NYTimes suggests that the use of solid fuel rocket motors results in more accurate missles that when using liquid fuel motors. "Solid fuel dramatically increases the accuracy of a missile while a liquid fuel missile is not very accurate in hitting targets."  How is this? --Hooperbloob 17:35, 27 August 2006 (UTC)
replies: text: NYT has it wrong.  In their defense, there are a number of reasons to prefer solid propellants for missiles.  The biggest is storage and operation -- solids can be stored ready to fire almost indefinitely.  Storable liquid propellants, as a rule, are toxic, corrosive, degrade over time (months or years), and are less dense than solid propellants.  The density means that for many military applications where volume is limited (eg space in a sub / truck / etc) the solids perform better, despite slightly lower Isp, due to the increased quantity of propellant in the same volume.  Also, solid motors are frequently simpler and therefore cheaper to build in quantity, though the higher propellant cost (mainly due to labor-intensive casting procedures) may offset or reverse this.  If anything, liquids would actually be more accurate, since solid propellant burn rates depend on things like storage temperature, which makes for a less precise thrust curve.  I'm guessing somehow the reporter translated "solid propellants make for better missiles" into "solid propellants make for more accurate missiles." Evand 20:33, 27 August 2006 (UTC)
replies: text:  OK, that tends to make more sense, thanks for the interpretation.--Hooperbloob 22:38, 27 August 2006 (UTC)
thread_title: More accurate?

message: "In the USA, the use of a steel casing requires a federal permit when building models."
This was in the article.  I believe it to be incorrect, so I marked it , and have now removed it.  I know that steel casings are not permitted under NFPA-1127, Tripoli, or NAR rules, but I don't believe it is illegal in any way, or requiring of special permitting.  If anyone has a reference, please feel free to put it back. Evand 20:14, 17 October 2006 (UTC)
thread_title:  Steel casings 

message: Is the following really true?  If so, it really needs to be cited, 'cause, well, I don't believe it:
:"The exhaust from a solid rocket motor contains hydrochloric acid and aluminium oxide. These have a negative effect on the environment. Furthermore, for military use, the smoke trail and the infrared radiation from the hot particles make it possible to detect the launch from space. These problems led to the research in smokeless grain which contains nitrogen-containing organic molecules."
I'm sure the military stuff is true, but is the presence of "hydrochloric acid and aluminum oxide" really ubiquitous or does it depend on the type of propellant used?  In the same vein, does the problem with detectable launches really hinge on the presence of those specific compounds in the exhaust, as this implies? jhf (talk) 19:39, 19 June 2008 (UTC)
thread_title:  Exhaust 

message: what arab army used rockets in 13th century? or was there any arab country to have a regular army? if this is an encyclopedia the information must be more accurate.  —Preceding unsigned comment added by 85.103.220.159 (talk) 22:45, 27 November 2008 (UTC)
thread_title:  history 

message: The article makes this claim: "The vast majority of amateur rocket motors utilize a composite propellant, most commonly APCP." That's news to me. I don't know what the G and larger motors use for fuel, but the smaller engines all use black powder. —MiguelMunoz (talk) 03:21, 16 March 2009 (UTC)
replies: text: I don't believe that's right. I believe the smaller motors (which tend to be commercially produced) use black powder, and the larger motors, whether commercial or not, use APCP or other alternatives to black powder. Black powder is more dangerous for amateurs to handle. But even if you're correct, the article is wrong. —MiguelMunoz (talk) 09:24, 26 March 2009 (UTC)
replies: text: In my experience in the hobby, you're absolutely correct.  However, the term "amateur", in context, means made by an amateur, not used by an amateur.  In general, amateur rocketry refers to the practitioner producing their own motors, and terms such as hobby rocketry, model rocketry, and low-, mid-, or high-power rocketry refer to the use of commercially made motors in a commercial or home built airframe. Evand (talk) 15:39, 26 March 2009 (UTC)
replies: text:  Okay, so this is turning into a question of semantics. I think the problem lies with ambiguity in the phrase "amateur rocket motors" in the sentence in question. It can be read as "amateur rocket-motors" or as "amateur-rocket motors." (Note the placement of the hyphen.) It seems you interpret this to mean amateur motors for rockets but I read it as motors for amateur-rockets. Maybe the sentence could be reworded as "The vast majority of rocket motors built by amateurs utilize..." I also question your claim that the term "amateur rocketry" refers to the practitioner producing their own motors." To the uninitiated reader, the term "amateur rocketry" sounds like it's about amateur rockets, not amateur motors, so that's probably how the term should be used. Having said that, I want to thank you for clarifying. I think this gets to the root of our disagreement. —MiguelMunoz (talk) 19:59, 26 March 2009 (UTC)
replies: text:  I don't know what the normal WP policy is on jargon and technical terms.  When used by people in the hobby, the phrase amateur rocketry (or amateur rocket motor) is unambiguous, at least in my experience.  To anyone else, it could easily mean either.  See for example amateur rocketry.  I think the article should use the term in a manner consistent with the contextual definition, but being clear to people who don't know much about the subject is the point of an encyclopedia.  Out of curiosity, do you fly rockets?  (I'm not trying to say you're not qualified, I'm just curious what your perspective on the article is; the perspective of insiders like myself can get myopic.) Evand (talk) 06:38, 27 March 2009 (UTC)
replies: text:  I haven't looked up that policy either, but I will when I get a bit more time. Sometimes technical terms are chosen carefully and work well, other times they can be very misleading to anyone outside the field. Whatever we do, I think clarity and accuracy should be our highest concerns. And I agree with you that, in context, it's pretty clear that they're talking about the motors, but I'd still like to see it reworded. I'm thinking of changing it to either "amateur motors" or "amateur-built rocket motors." I also noticed a problem with the first sentence, where it says "Solid fuel rockets can be bought for use in model rocketry; they are normally small cylinders of fuel..." So it's talking about the motor, not the rocket. I'd like to reword this, too. To satisfy your curiosity, I used to fly rockets as a kid, and again as an adult a few years ago, but I haven't done that in a while. I only launched smaller rockets. I rarely used D engines and never used anything bigger. What's your experience? —MiguelMunoz (talk) 01:43, 30 March 2009 (UTC)
replies: text:  Either of those changes sounds fine to me.  I flew a variety of Estes rockets as a kid; more recently I've flown high power stuff, mostly I-J class.  I've done a little solid propellant amateur work (KN/Epoxy, mostly), and am currently working on a M-class nitrous hybrid that will hopefully fly later this year (underloaded as a K or L motor) before flying at full load some time after that.  Progress has been slow as we've taken a bit of a detour to improve test stand instrumentation, including designing a more appropriate data acquisition system from scratch (and of course real life has intervened).  I've also worked professionally with biprops.  Evand (talk) 02:55, 30 March 2009 (UTC)

text:  Okay, I made the changes, but I would still like to see a reference for the section. It may be more accurate, but it's still unsourced. —MiguelMunoz (talk) 06:21, 31 March 2009 (UTC)
thread_title:  Hobbyist fuel 

message: just wondering - if you had a small rocket that used high explosives, i.e. pure RDX, would that get you more fuel efficiency, or just blow you into tiny pieces?  RowanEvans (talk) 16:27, 18 March 2009 (UTC)
replies: text: Energetic fuels like RDX and HMX see some use in military propellants.  Performance is similar to APCP type propellants, but without the chlorine and solids that make a highly visible exhaust plume.  In rocket operation, they burn much like other fuels (ie without detonating).  However, between expense and safety concerns they don't see much use outside the military. Evand (talk) 01:53, 19 March 2009 (UTC)

text: From what I've read, fuels that burn too fast risk bursting the combustion chamber. In black-powder rockets, this can happen if cracks form in the compacted fuel. —MiguelMunoz (talk) 09:50, 26 March 2009 (UTC)
replies: text: I'd have to dig out my copy of Sutton to be certain, but my recollection is that nitramine fuels burn at similar rates as double base propellants or APCP.  The precise burn rate and nozzle size are matched to each other, and burn rate catalysts / inhibitors can be used to tailor the burn rate to the mission requirements.  I don't know of any reason to believe that nitramine propellants are any more or less prone to cracking than APCP and such; I think that's mostly a property of the binder used. Evand (talk) 15:35, 26 March 2009 (UTC)
replies: text:  I wasn't referring to cracking in nitramine or APCP. I was addressing the original question about burn rates, not your reply. Looking back at the article, I realize I was just making the same point as the 2nd to last paragraph in the "Design" section. —MiguelMunoz (talk) 20:13, 26 March 2009 (UTC)
thread_title:  High explosives 

message: The terms "solid-fuel rocket" and "liquid-fuel rocket" are misnomers of common usage. "Rocket fuel" is not equivalent to "rocket propellant". "Solid propellant rocket" and "liquid propellant rocket" are technically correct descriptions.  All rockets use propellant, which is the mass reacted against to produce thrust. Rocket propellants may, or may not, consist of fuel and oxidizer which burn to produce hot gas which is ejected from a nozzle to generate the thrust.  While "solid propellant rocket" is often shortened to just "solid rocket", the phrase "solid-fuel rocket" is imprecise and not generally used within the industry. Jets (air-breathing) may only require a supply of fuel, but no rocket runs on fuel alone. My point is that the title "Solid-fuel rocket" is itself a misnomer that would better read "Solid propellant rocket". The casual substitution of "solid fuel" for "solid propellant" in the text of the article is relatively harmless, but such technically inaccurate terminology does not seem as appropriate in the title. As a matter of interest, solid rocket manufacturers usually refer to their propulsive devices as motors, while liquid rocket manufacturers refer to theirs as engines. The difference is merely a reflection of historical origins. Magneticlifeform (talk) 04:18, 12 October 2010 (UTC)
thread_title:  No "solid-fuel" rockets  

message: I am questioning the trust curves shown in the Solid-fuel rocket:grain geometry.  My understanding is that, essentially, the thrust is a function of grain surface area.  A simple circular bore would quickly reach 100% of thrust and may peak at 200-300% then drop down as the grain is fully consumed. The graph of a circular bore shows essentially a fixed thrust (excluding ignition and burnout). The My question: are the diagrams correct, or do they need correction? Jim1138 (talk) 07:03, 24 May 2011 (UTC)
thread_title:  Erroneous thrust curve 

message: The "History" section states that John Parson's asphalt/potassium perchlorate composite propellant had significantly higher specific impulse than the double base propellants of that time.  I have 2 books (Hunley and Warren) which report that the specific impulse of Parson's propellant was 186 seconds.  At the same time I have Gruntman's book reporting that Goddard had tested double base propellants at Isp>230 seconds years earlier and rocket data on the HVAR WWII rocket which implies an Isp of 198 seconds, which is still greater than 186 seconds.  The significant advantage of the Parsons propellant was that it had a slow burn-rate suitable for JATO applications without suffering from the short shelf-life of the dry, compressed powder propellants that Galcit had already tried.  I do not trust a single data point (198 sec) as a basis for changing the statement in the History section, but if there is a WWII rocket buff out there with more WWII rocket Isp data, perhaps he (or she) could look into it. Magneticlifeform (talk) 05:23, 31 August 2011 (UTC)
thread_title:  Parson's propellant higher specific impulse than double base? 

message: how do they light one? Pb8bije6a7b6a3w (talk) 21:12, 2 October 2016 (UTC)
replies: text: The use an ignitor on the top segment. It is a small ordnance device that is (usually) electrically activated and provides the first combustion. Its also the last item to be installed, since after that the rocket is considered "armed". – Baldusi (talk) 13:32, 3 October 2016 (UTC)
thread_title:  how do they light one? 

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