This is the
talk page for discussing improvements to the
Aerojet LR87 article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This article is written in American English, which has its own spelling conventions (color, defense, traveled) and some terms that are used in it may be different or absent from other varieties of English. According to the relevant style guide, this should not be changed without broad consensus. |
This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||
|
See Talk:LGM-25C Titan II#One lump or two. Andrewa ( talk) 05:29, 13 July 2013 (UTC)
That discussion has been dormant for some time. Meanwhile, our articles on the LR-87 and the rocket missiles that it propelled remain woefully inconsistent. And really authoritative sources seem surprisingly hard to find.
There are I think two possibilities:
Either way requires a considerable amount of work to implement, so I'd like to have a strong consensus on which to pursue.
It seems clear to me that neither a single-nozzle nor single-chamber version of the LR-87 has ever been built. In all versions, several vital components are shared between the two chambers and nozzles in such a way that the two can only be fired as a single unit. To scale these systems down to support only one nozzle has never been attempted.
However, one now-inactive editor claimed that the LR-87-5 was a single chamber engine, which was fitted as a pair on the Titan II first stage. That is in contrast to the LR-87-3 of the Titan I, which was a two chamber engine with shared turbo-pump.... [1] This seems quite widely believed, but despite considerable effort we have no good sources to support it.
An IP with no other contributions has said It never occurred to me to consider it a single engine. We always referred to them as "engines". To be precise (and having worked on them in the USAF, I know)...two thrust chambers and four turbo pumps (two per thrust chamber). That of course suggests that they are two engines, but they did share peripheral support systems. The hot gas generator (for pressurizing the propellant tanks) the lubrication system and the drive unit (a small reaction chamber where a negligible amount of propellant was reacted to drive the turbopumps for the thrust chambers) were critical parts of the engines. In that respect it is proper to say that since the thrust chambers could not operate independently, they must, therefore be considered a single unit. (my emphasis) [2]
That to me explains a lot. The in-house jargon was always engines, but the more considered opinion is that it's a single engine. All versions.
And of course we will always have well-meaning editors who take one look at the photo at left and say to themselves it clearly has two engines and "correct" the text to match. (I have the same trouble with the photo of my fretless ABG. [3]) From that point of view, it would be really good to have a clear conclusion to our discussion here.
See also RD-180 which is always considered a single two-nozzle engine AFAIK.
Comments? I have posted heads-ups at WikiProject Rocketry (which seems inactive) and WikiProject Aviation. Andrewa ( talk) 02:04, 15 March 2014 (UTC)
And now also at WikiProject Military history and WikiProject United States following the addition of those to the talk page header [4] by a very active [5] IP. Andrewa ( talk) 11:01, 15 March 2014 (UTC)
We now have four options to consider, as I see it:
The sources we have so far all support option 1. Andrewa ( talk) 18:47, 15 March 2014 (UTC)
I have just posted extra heads-ups at all affected articles that I can find (see #Affected articles below) and also at Wikipedia talk:WikiProject Spaceflight#Number of first stage engines of the Titan GLV etc. Andrewa ( talk) 23:47, 17 March 2014 (UTC)
I think it's worth having a separate conversation on the question of exactly what we must reject as WP:OR. This is probably the clearest case I have yet seen of a basic problem we sometimes encounter in applying this policy.
Just suppose that we can't find a reliable source that explicitly says either the LR87(-x) is a single two-nozzle engine, or the LR87(-x} is a single nozzle engine always used in pairs, or words to that effect either way. That's a thought experiment, we haven't found such sources either way so far and may or may not. Or there's a third possibility, we might find a source that explicitly says authorities differ as to whether a two-nozzle LR87(-x) is a single engine or an assembly of two engines. That would be even better, but again we may or may not find such a source, and haven't yet.
In any of these three cases, we would have a reliable secondary source to cite. But we don't have any such yet. So let's just suppose for the purpose of this section that we have no such RSS.
Let's further suppose that we have reliable sources that do use both the term engine and the term engines in referring to a single two-nozzle LR87(-x) assembly. That also appears to be the case so far, and for the purposes of this section let's assume it is the case.
What do we do?
We do need to do something. I mean, we could I suppose just delete and protect all the relevant articles, problem solved, but obviously that's overkill. Or we can, in the infoboxes etc, avoid saying number of engines at all, and instead we use some safe if awkward terminology like number of main engine nozzles.
But that on its own doesn't make for a good encyclopedia. It's far more helpful to the reader if we also say why we are avoiding the simple term engine. And this is also necessary to prevent endless edit activity which may not quite be an edit war but is equally pointless and time consuming, as editor after editor finds a reliable source which simply uses engine or engines, and then proceeds in good faith to "correct" the article(s). (Which is the situation we now have.)
So in this case I would argue, we need to in some way report on the primary sources we have, to point out in a footnote perhaps that sources are not consistent in their terminology.
Whether we elect to arbitrarily follow one usage or the other, or whether we instead just avoid either and accept some rather awkward and legalistic phrasing as a result, I don't much care. The point is, either way I think we need a footnote or similar to say why we are doing what we are doing, both to make for the best reader experience (our bottom line) and to reduce the overhead of endlessly reinventing the wheel.
I can't see any way of avoiding this footnote, or any way that it doesn't represent original research. In the scenario described above, it's based entirely on primary sources, because the assumption is that, strictly speaking, there are no secondary ones regarding this particular issue.
Comments? Andrewa ( talk) 18:02, 16 March 2014 (UTC)
I think it's now timely to survey exactly which articles are affected by the question of whether the two-nozzle LR-87 assembly is one engine or two, per #Number of nozzles above. Bolding is my emphasis.
Are there any I've missed?
Now the above seems mostly but not entirely consistent with the theory that the Titan I LR-87-3 first stage engine was a single two-nozzle engine, but the Titan II LR-87-5 first stage engines had sufficient independence between the chambers for the assembly to be considered two single nozzle engines. This has been suggested in previous talk page discussions, here is just one example, so it needs to be aired I think. But no evidence (apart from the opinion of contributors, based on their interpretation of the specifications) has been produced that this is the case, despite a great deal of discussion. I'm very interested in any that can be found.
And there are still some other obvious but relatively minor problems. The HGM-25A Titan I and LGM-25C Titan II articles for example are each internally inconsistent, despite each describing a single model of LR-87. Note also that one of these missiles used the LR-87-3 and the other the LR-87-5. We are at least consistently and comprehensively inconsistent! (;->
My current theory is that our current content is just confused and confusing, and that it needs to be fixed. But I don't recommend fixing any of it right now. Let's first try for a consensus on what if anything needs fixing, and how to fix it. Andrewa ( talk) 07:35, 18 March 2014 (UTC)
It appears obvious that some articles are going to be changed as a result of this discussion.
But, suppose we do decide that (with suitable explanations and references) we're going (as I hope) to always regard the LR-87 as a single engine with two nozzles, all versions. Does that mean we simply change every infobox that says Engines: 2 x LR87 or similar to say Engines: 1 LR87 two-nozzle assembly or similar?
No way. We need to check what else the infobox and article says, and whether thrust and engine weight are quoted for the whole stage or per engine or per nozzle, for example, and whether they even matched up as we found the article. Failure to do this will introduce errors of fact (and almost certainly has in the past but I have no diff to quote right now). Andrewa ( talk) 03:17, 19 March 2014 (UTC)
It seems to me that we have strong consensus above that the various articles listed are currently inconsistent, and that this should be fixed,
It further seems to me that we have a rough but policy and evidence based consensus above that the best way to do this is to treat all variants of the LR-87 as a single engine with two nozzles. Most but not all sources, and the best sources, are consistent on this.
But I'll wait a little longer before starting to bring the articles into consistency based on this understanding. Andrewa ( talk) 01:01, 24 March 2014 (UTC)
The USAF considered the LR87 as 1 engine with 2 thrust chambers. "T.O. 21M-HGM25A-1-1 Technical Manual Operation and Organizational Maintenance HGM-25A Missile Weapon System" makes that very clear. Figure 1-60 "Stage I Rocket Engine Subassembly", on page 1-102, lists item 15 as Thrust Chamber 1, and item 17 as Thrust Chamber 2. Paragraph 1-243 (page 1-101) states "STAGE I ROCKET ENGINE. The Stage I rocket engine, designated LR87-AJ-3, consists of two engine subassemblies. (See figure 1-60.) The two subassemblies develop a total of 300,000 pounds of thrust and are mounted on a common engine frame . . . The subassemblies are similar and are interconnected by instrumentation and electrical components."
Sutton in "History of Liquid Propellent Rocket Engines" states "The booster engine has twin LPREs with regeneratively cooled gimbal-mounted thrust each with it's own turbopump." [1]
Mark Lincoln ( talk) 01:59, 16 February 2016 (UTC)
I've moved this list to User:andrewa/LR-87 article updates to remove the need to sign changes. Feel free to update it there. Andrewa ( talk) 06:47, 5 April 2014 (UTC)
I've started a page as a temporary repository for statistics such as engine weight and thrust, to help with the checking of whether any are understated by a factor of two because they are quoted for a conbustion chamber and nozzle. See User:andrewa/LR-87 versions, and feel free to update it there. Andrewa ( talk) 06:47, 5 April 2014 (UTC)
I have some LR87 numbers for you from a reputable source.
[2]
Titan I LR87-AJ-3
Thrust = 382,000 (lbs vacuum)
Thrust = 300.000 (lbs sea level
Specific Impulse = 258.8 (S sea level)
Specific Impulse = 315/329 (Is S vacuum)
Propellants = LOX/Kerosene (RP-1?)
Mixture Ratio = 202
Chamber Pressure = NA (psia)
Nozzle Area Ratio = 8
Titan II LR87-AJ-5
Thrust = 473,800 (lbs vacuum)
Thrust = 430.000 (lbs sea level
Specific Impulse = 278 (S sea level)
Specific Impulse = 285.2//309 (Is S vacuum)
Propellants = NTO/Aerozine 50
Mixture Ratio = 1.930
Chamber Pressure = 795 (psia)
Nozzle Area Ratio = 8
Titan II LR87-AJ-5
Thrust = 473,800 (lbs vacuum)
Thrust = 460.000 (lbs sea level
Specific Impulse = 258.8 (S sea level)
Specific Impulse = 285.2/309 (Is S vacuum)
Propellants = NTO/Aerozine 50
Mixture Ratio = 1.930
Chamber Pressure = 795 (psia)
Nozzle Area Ratio = 8
Titan III LR87-AJ-11
Thrust = 527,800 (lbs vacuum)
Thrust = 430.000 (lbs sea level
Specific Impulse = 258 (S sea level)
Specific Impulse = 296/318 (Is S vacuum)
Propellants = NTO/Aerozine 50
Mixture Ratio = 1.75
Chamber Pressure = 823 (psia)
Nozzle Area Ratio = 12
Titan IV LR87-AJ-11A
Thrust = 550,900 (lbs vacuum)
Thrust = 489.000 (lbs sea level
Specific Impulse = NA (S sea level)
Specific Impulse = 303.5/316.2 (Is S vacuum)
Propellants = NTO/Aerozine 50
Mixture Ratio = 1.91
Chamber Pressure = 854 (psia)
Nozzle Area Ratio = 16
Mark Lincoln ( talk) 19:35, 16 February 2016 (UTC)
Astronautics is a useful initial source. Sutton is a far better source. Beyond that you have to consult a variety of sources. The performance of the LR91 is specified for a vacuum. The details I have provided are the most accurate I could determine. The LR87 was an astounding engine which has burned a wider variety of propellants than any other engine I am aware of. Note that in the Titan I LR87-AJ-3 it burned lox/RP-1, in the LR87-AJ-5, and later LR87-7, LR87-AJ-11 and 11A it burned Nitrogen Tetroxide-Aerozine 50. The LR91-2 ran on LOX/RP1 while the LR91-3 ran on Nitrogen tetroxide and Aerozine 50 as did the LR91-7, 9 & 11. The LR87 was also fueled with Alumazine, which was 56.7% Aerozine 50, .3% Carbopol 904 gelling agent, mixed with aluminum powder to attain a higher specific impulse for the proposed Titan IIA. The gelled aluminum fuel suffered instabilities and cooling problems and was not pursued. The LR87 was also successfully operated with Liquid Oxygen oxidizer with Liquid Hydrogen as the fuel which required modification to the injectors and fuel pump. The LOX/LH2 engine was run some 50 times. I know of no other rocket motor which was operated with four different fuels and two oxidizers. An amazing rocket engine.
Mark Lincoln ( talk) 22:02, 22 January 2022 (UTC)
Did this version ever fly? It seems to have been ground tested only. Much is made of the fact that the LR-87 in its various versions used three different fuel combinations, but it seems to me that only two of them ever flew.
And it's just possible that the LH2 version was a single chamber engine... see
Interesting... It might explain a lot. Andrewa ( talk) 00:58, 5 April 2014 (UTC)
"One Titan I booster engine with a new fuel pump was later ajso ground tested with LOX/H2."
[3]
Mark Lincoln ( talk) 18:03, 16 February 2016 (UTC)
There is no LR-87 and never was. The proper nomenclature is LR87. The designation system in use for jet and rocket engines excludes placing a hyphen between the letters describing the engine and the numbers indicating the serial acceptance of the engine.
Below is an document explaining the nomenclature in use since 1945:
"1. Representatives of the Navy Bureau of Aeronautics and of the Air Technical Services Command have agreed on the following general system of designating aircraft jet propulsion engines:
a. The system will be composed of two parts separated by a dash. The first part will consist of a letter(s) describing the general nature of the engine and a number designating the serial acceptance of the type. The second part shall consist of a number designating model under the basic type. The letters to be used in the first part of the designation are as follows with definitions as shown:
(1) J – Jet engine (without propeller)
T – Jet Engine (with propeller)
R – Rocket
PJ – Intermittent Jet Engine (Example: Buzz Bomb Engine)
RJ – Ram Jet engine
b. The odd numbers for the first and second parts of the designations will be used by the Army and the even numbers by the Navy. A particular engine will be identified by the same designation for both the AAF and the Bureau of Aeronautics. The number designating the engine type will begin with the number 30 in order to avoid confusion with some Navy airplane designations in which the new letters are used. Examples of this system are as follows:
(1) J31-1 – First Army model of first Army type of a jet engine (without propeller)
31-2 – First Navy model of first Army type of a jet engine (without propeller)
J31-3 – Second Army model of first Army type of a jet engine (without propeller)
J30-1 – First Army model of first Navy type of a jet engine (without propeller)" [4]
The USAF "T.O. 21M-HGM25A-1-1 Technical Manual Operation and Organizational Maintenance HGM-25A Missile Weapon System" defines the first stage engine in paragraph 1-243 (page 1-101) as: "STAGE I ROCKET ENGINE. The Stage I rocket engine, designated LR87-AJ-3, consists of two engine subassemblies."
[5]
The designation means Liquid Rocket #87 AeroJet second USAF version. The first USAF version was the LR87-AJ-1, the third USAF version LR87-AJ-5 was used in the Titan II.
Any comments before I change the name to the proper one?
Mark Lincoln ( talk) 02:23, 16 February 2016 (UTC) October 24, 2005 issue there was the last A
I decided this morning to search Aviation Week & Space Technology's archives to see when the "RL-87" first occurred. I searched for Aerojet LR87 and Aerojet LR-87. The results was interesting. The first mention of the LR-87 in AvLeak & Space Mythology was in the August 24, 1959 issue on page 27. "Models Show Configuration of Titan Engines." The caption mentions the "LR-87" and "LR-91." The last article in the AvLeak archive was "Titan, Adieu" covering the last Titan launch. The article in the October 24, 2005 issue reported "The flight also marked the last mission for the . . . Aerojet LR87 and LR91 series rocket engines . . ." In the intervening 46 years I found many mentions of the "RL-87 and LR87 (and LR91 & LR-91) their was no consistency. The same was true with the Atlas's LR89 & LR105 - worse actually because AvLeak usually used the Rocketdyne designation for the whole propulsion package (MA-3, MA-5, etc). I wonder if Aviation Week started the whole confusion?
Mark Lincoln ( talk) 23:04, 17 February 2016 (UTC)
The Titan 3M was about to be built when MOL was canceled. NASA considered using it as a vehicle for an enlarged Big Gemini 120 for space rescue. The The 3M would have had a quicker response time compared to the Saturn IB. "Extremes of estimated time interval to reach an emergency site in a low earth orbit are 4 hr. minimum and 144 hr. maximum. [6] Another scheme was to use it to boost refurbished Apollo Command Modules for space rescue. [7] NASA estimated Titan 3M would be cheaper, $15-16 million vs Saturn IB at $28 million. [8] The 7 section solid strap on was tested. [9] The modified LR87 had been successfully tested. [10] Ground Support Equipment was built [11] The fuel used in the modified YRL87-AJ-11 was "Alumazine 50 "a suspension of powdered aluminum in (gelled) Hydrazine.". [12] The last cited article also explains the "M" in Titan 3M. It stood for "Metalized." The new fuel required modifications to the YRL87-11 which are detailed in the "Stage I Engine Demonstration Testing" report.
This would make the LR87 unique in being the only Large Liquid Propellent Engine to have been fired with four different Oxidizer/Fuel combinations. Anyone have more information on the "almost flew" YLR87-11" for the Titan 3M (or IIIM)*?
Mark Lincoln ( talk) 03:30, 18 February 2016 (UTC)
I have located the patent for the metalized gel fuel. Patent 3,607,470 is titled "Thixotropic gelled liquid rocket fuel containing hydrazine and aluminum hydride coated with a semicarbazide copolymer" The patent says the inventor was James M. Lucas El Dorado Hills, Calif., and it was assigned to Aerojet-General Corporation El Monte, Calif.
A careful (and tedious) reading of "Stage I Engine Demonstration Testing" left me certain that the modifications were to increase thrust and man rate the engine. I have turned up no evidence that the modified YLR87-AJ-11 was ever fired with Aumazinen 50. There has been a lot of research going on with gelled fuels. [13] [14] [15] [16]
Mark Lincoln ( talk) 20:45, 22 February 2016 (UTC)
References
{{
cite journal}}
: Cite journal requires |journal=
(
help)
{{
cite journal}}
: |issue=
has extra text (
help); Check |url=
value (
help)
{{
cite journal}}
: Cite journal requires |journal=
(
help)
{{
cite journal}}
: Cite journal requires |journal=
(
help)
Hello fellow Wikipedians,
I have just added archive links to one external link on
LR-87. Please take a moment to review
my edit. If necessary, add {{
cbignore}}
after the link to keep me from modifying it. Alternatively, you can add {{
nobots|deny=InternetArchiveBot}}
to keep me off the page altogether. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true to let others know.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— cyberbot II Talk to my owner:Online 01:56, 25 February 2016 (UTC)
The result of the move request was: Moved. unopposed. ( non-admin closure) Dicklyon ( talk) 01:51, 11 February 2017 (UTC)
LR-87 →
LR87 – US military engine designation did NOT use hyphens
Petebutt (
talk) 12:08, 29 January 2017 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on LR-87. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 21:00, 9 May 2017 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on LR-87. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 06:09, 11 November 2017 (UTC)
As always with the Wikipedia some individuals are of the opinion that the actual designation is not acceptable because they prefer an imaginary one. Military rocket and jet engines have no hyphen between the letter and numbers. The J57 was never a J-57, nor the LR87 ever a LR-87. It has long been argued by self-appointed idividuals, who make up designations to suit their individual desires, that the imaginary world in which they live rules. This does not only happen with engine designations. The same fantasists also ignore the British official system for designating airships with a R separated from the number by a period. As they are self-appointed mavins there is no reasoning with their silliness. So the Wikipedia has designations which are absolutely wrong as demanded by individuals who believe that "reality" has to meet their deires rather than what is the truth. This is an interesting situation for what aspires to be an encylopedic resource.
Mark Lincoln ( talk) 22:26, 22 January 2022 (UTC)
This is the
talk page for discussing improvements to the
Aerojet LR87 article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This article is written in American English, which has its own spelling conventions (color, defense, traveled) and some terms that are used in it may be different or absent from other varieties of English. According to the relevant style guide, this should not be changed without broad consensus. |
This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||
|
See Talk:LGM-25C Titan II#One lump or two. Andrewa ( talk) 05:29, 13 July 2013 (UTC)
That discussion has been dormant for some time. Meanwhile, our articles on the LR-87 and the rocket missiles that it propelled remain woefully inconsistent. And really authoritative sources seem surprisingly hard to find.
There are I think two possibilities:
Either way requires a considerable amount of work to implement, so I'd like to have a strong consensus on which to pursue.
It seems clear to me that neither a single-nozzle nor single-chamber version of the LR-87 has ever been built. In all versions, several vital components are shared between the two chambers and nozzles in such a way that the two can only be fired as a single unit. To scale these systems down to support only one nozzle has never been attempted.
However, one now-inactive editor claimed that the LR-87-5 was a single chamber engine, which was fitted as a pair on the Titan II first stage. That is in contrast to the LR-87-3 of the Titan I, which was a two chamber engine with shared turbo-pump.... [1] This seems quite widely believed, but despite considerable effort we have no good sources to support it.
An IP with no other contributions has said It never occurred to me to consider it a single engine. We always referred to them as "engines". To be precise (and having worked on them in the USAF, I know)...two thrust chambers and four turbo pumps (two per thrust chamber). That of course suggests that they are two engines, but they did share peripheral support systems. The hot gas generator (for pressurizing the propellant tanks) the lubrication system and the drive unit (a small reaction chamber where a negligible amount of propellant was reacted to drive the turbopumps for the thrust chambers) were critical parts of the engines. In that respect it is proper to say that since the thrust chambers could not operate independently, they must, therefore be considered a single unit. (my emphasis) [2]
That to me explains a lot. The in-house jargon was always engines, but the more considered opinion is that it's a single engine. All versions.
And of course we will always have well-meaning editors who take one look at the photo at left and say to themselves it clearly has two engines and "correct" the text to match. (I have the same trouble with the photo of my fretless ABG. [3]) From that point of view, it would be really good to have a clear conclusion to our discussion here.
See also RD-180 which is always considered a single two-nozzle engine AFAIK.
Comments? I have posted heads-ups at WikiProject Rocketry (which seems inactive) and WikiProject Aviation. Andrewa ( talk) 02:04, 15 March 2014 (UTC)
And now also at WikiProject Military history and WikiProject United States following the addition of those to the talk page header [4] by a very active [5] IP. Andrewa ( talk) 11:01, 15 March 2014 (UTC)
We now have four options to consider, as I see it:
The sources we have so far all support option 1. Andrewa ( talk) 18:47, 15 March 2014 (UTC)
I have just posted extra heads-ups at all affected articles that I can find (see #Affected articles below) and also at Wikipedia talk:WikiProject Spaceflight#Number of first stage engines of the Titan GLV etc. Andrewa ( talk) 23:47, 17 March 2014 (UTC)
I think it's worth having a separate conversation on the question of exactly what we must reject as WP:OR. This is probably the clearest case I have yet seen of a basic problem we sometimes encounter in applying this policy.
Just suppose that we can't find a reliable source that explicitly says either the LR87(-x) is a single two-nozzle engine, or the LR87(-x} is a single nozzle engine always used in pairs, or words to that effect either way. That's a thought experiment, we haven't found such sources either way so far and may or may not. Or there's a third possibility, we might find a source that explicitly says authorities differ as to whether a two-nozzle LR87(-x) is a single engine or an assembly of two engines. That would be even better, but again we may or may not find such a source, and haven't yet.
In any of these three cases, we would have a reliable secondary source to cite. But we don't have any such yet. So let's just suppose for the purpose of this section that we have no such RSS.
Let's further suppose that we have reliable sources that do use both the term engine and the term engines in referring to a single two-nozzle LR87(-x) assembly. That also appears to be the case so far, and for the purposes of this section let's assume it is the case.
What do we do?
We do need to do something. I mean, we could I suppose just delete and protect all the relevant articles, problem solved, but obviously that's overkill. Or we can, in the infoboxes etc, avoid saying number of engines at all, and instead we use some safe if awkward terminology like number of main engine nozzles.
But that on its own doesn't make for a good encyclopedia. It's far more helpful to the reader if we also say why we are avoiding the simple term engine. And this is also necessary to prevent endless edit activity which may not quite be an edit war but is equally pointless and time consuming, as editor after editor finds a reliable source which simply uses engine or engines, and then proceeds in good faith to "correct" the article(s). (Which is the situation we now have.)
So in this case I would argue, we need to in some way report on the primary sources we have, to point out in a footnote perhaps that sources are not consistent in their terminology.
Whether we elect to arbitrarily follow one usage or the other, or whether we instead just avoid either and accept some rather awkward and legalistic phrasing as a result, I don't much care. The point is, either way I think we need a footnote or similar to say why we are doing what we are doing, both to make for the best reader experience (our bottom line) and to reduce the overhead of endlessly reinventing the wheel.
I can't see any way of avoiding this footnote, or any way that it doesn't represent original research. In the scenario described above, it's based entirely on primary sources, because the assumption is that, strictly speaking, there are no secondary ones regarding this particular issue.
Comments? Andrewa ( talk) 18:02, 16 March 2014 (UTC)
I think it's now timely to survey exactly which articles are affected by the question of whether the two-nozzle LR-87 assembly is one engine or two, per #Number of nozzles above. Bolding is my emphasis.
Are there any I've missed?
Now the above seems mostly but not entirely consistent with the theory that the Titan I LR-87-3 first stage engine was a single two-nozzle engine, but the Titan II LR-87-5 first stage engines had sufficient independence between the chambers for the assembly to be considered two single nozzle engines. This has been suggested in previous talk page discussions, here is just one example, so it needs to be aired I think. But no evidence (apart from the opinion of contributors, based on their interpretation of the specifications) has been produced that this is the case, despite a great deal of discussion. I'm very interested in any that can be found.
And there are still some other obvious but relatively minor problems. The HGM-25A Titan I and LGM-25C Titan II articles for example are each internally inconsistent, despite each describing a single model of LR-87. Note also that one of these missiles used the LR-87-3 and the other the LR-87-5. We are at least consistently and comprehensively inconsistent! (;->
My current theory is that our current content is just confused and confusing, and that it needs to be fixed. But I don't recommend fixing any of it right now. Let's first try for a consensus on what if anything needs fixing, and how to fix it. Andrewa ( talk) 07:35, 18 March 2014 (UTC)
It appears obvious that some articles are going to be changed as a result of this discussion.
But, suppose we do decide that (with suitable explanations and references) we're going (as I hope) to always regard the LR-87 as a single engine with two nozzles, all versions. Does that mean we simply change every infobox that says Engines: 2 x LR87 or similar to say Engines: 1 LR87 two-nozzle assembly or similar?
No way. We need to check what else the infobox and article says, and whether thrust and engine weight are quoted for the whole stage or per engine or per nozzle, for example, and whether they even matched up as we found the article. Failure to do this will introduce errors of fact (and almost certainly has in the past but I have no diff to quote right now). Andrewa ( talk) 03:17, 19 March 2014 (UTC)
It seems to me that we have strong consensus above that the various articles listed are currently inconsistent, and that this should be fixed,
It further seems to me that we have a rough but policy and evidence based consensus above that the best way to do this is to treat all variants of the LR-87 as a single engine with two nozzles. Most but not all sources, and the best sources, are consistent on this.
But I'll wait a little longer before starting to bring the articles into consistency based on this understanding. Andrewa ( talk) 01:01, 24 March 2014 (UTC)
The USAF considered the LR87 as 1 engine with 2 thrust chambers. "T.O. 21M-HGM25A-1-1 Technical Manual Operation and Organizational Maintenance HGM-25A Missile Weapon System" makes that very clear. Figure 1-60 "Stage I Rocket Engine Subassembly", on page 1-102, lists item 15 as Thrust Chamber 1, and item 17 as Thrust Chamber 2. Paragraph 1-243 (page 1-101) states "STAGE I ROCKET ENGINE. The Stage I rocket engine, designated LR87-AJ-3, consists of two engine subassemblies. (See figure 1-60.) The two subassemblies develop a total of 300,000 pounds of thrust and are mounted on a common engine frame . . . The subassemblies are similar and are interconnected by instrumentation and electrical components."
Sutton in "History of Liquid Propellent Rocket Engines" states "The booster engine has twin LPREs with regeneratively cooled gimbal-mounted thrust each with it's own turbopump." [1]
Mark Lincoln ( talk) 01:59, 16 February 2016 (UTC)
I've moved this list to User:andrewa/LR-87 article updates to remove the need to sign changes. Feel free to update it there. Andrewa ( talk) 06:47, 5 April 2014 (UTC)
I've started a page as a temporary repository for statistics such as engine weight and thrust, to help with the checking of whether any are understated by a factor of two because they are quoted for a conbustion chamber and nozzle. See User:andrewa/LR-87 versions, and feel free to update it there. Andrewa ( talk) 06:47, 5 April 2014 (UTC)
I have some LR87 numbers for you from a reputable source.
[2]
Titan I LR87-AJ-3
Thrust = 382,000 (lbs vacuum)
Thrust = 300.000 (lbs sea level
Specific Impulse = 258.8 (S sea level)
Specific Impulse = 315/329 (Is S vacuum)
Propellants = LOX/Kerosene (RP-1?)
Mixture Ratio = 202
Chamber Pressure = NA (psia)
Nozzle Area Ratio = 8
Titan II LR87-AJ-5
Thrust = 473,800 (lbs vacuum)
Thrust = 430.000 (lbs sea level
Specific Impulse = 278 (S sea level)
Specific Impulse = 285.2//309 (Is S vacuum)
Propellants = NTO/Aerozine 50
Mixture Ratio = 1.930
Chamber Pressure = 795 (psia)
Nozzle Area Ratio = 8
Titan II LR87-AJ-5
Thrust = 473,800 (lbs vacuum)
Thrust = 460.000 (lbs sea level
Specific Impulse = 258.8 (S sea level)
Specific Impulse = 285.2/309 (Is S vacuum)
Propellants = NTO/Aerozine 50
Mixture Ratio = 1.930
Chamber Pressure = 795 (psia)
Nozzle Area Ratio = 8
Titan III LR87-AJ-11
Thrust = 527,800 (lbs vacuum)
Thrust = 430.000 (lbs sea level
Specific Impulse = 258 (S sea level)
Specific Impulse = 296/318 (Is S vacuum)
Propellants = NTO/Aerozine 50
Mixture Ratio = 1.75
Chamber Pressure = 823 (psia)
Nozzle Area Ratio = 12
Titan IV LR87-AJ-11A
Thrust = 550,900 (lbs vacuum)
Thrust = 489.000 (lbs sea level
Specific Impulse = NA (S sea level)
Specific Impulse = 303.5/316.2 (Is S vacuum)
Propellants = NTO/Aerozine 50
Mixture Ratio = 1.91
Chamber Pressure = 854 (psia)
Nozzle Area Ratio = 16
Mark Lincoln ( talk) 19:35, 16 February 2016 (UTC)
Astronautics is a useful initial source. Sutton is a far better source. Beyond that you have to consult a variety of sources. The performance of the LR91 is specified for a vacuum. The details I have provided are the most accurate I could determine. The LR87 was an astounding engine which has burned a wider variety of propellants than any other engine I am aware of. Note that in the Titan I LR87-AJ-3 it burned lox/RP-1, in the LR87-AJ-5, and later LR87-7, LR87-AJ-11 and 11A it burned Nitrogen Tetroxide-Aerozine 50. The LR91-2 ran on LOX/RP1 while the LR91-3 ran on Nitrogen tetroxide and Aerozine 50 as did the LR91-7, 9 & 11. The LR87 was also fueled with Alumazine, which was 56.7% Aerozine 50, .3% Carbopol 904 gelling agent, mixed with aluminum powder to attain a higher specific impulse for the proposed Titan IIA. The gelled aluminum fuel suffered instabilities and cooling problems and was not pursued. The LR87 was also successfully operated with Liquid Oxygen oxidizer with Liquid Hydrogen as the fuel which required modification to the injectors and fuel pump. The LOX/LH2 engine was run some 50 times. I know of no other rocket motor which was operated with four different fuels and two oxidizers. An amazing rocket engine.
Mark Lincoln ( talk) 22:02, 22 January 2022 (UTC)
Did this version ever fly? It seems to have been ground tested only. Much is made of the fact that the LR-87 in its various versions used three different fuel combinations, but it seems to me that only two of them ever flew.
And it's just possible that the LH2 version was a single chamber engine... see
Interesting... It might explain a lot. Andrewa ( talk) 00:58, 5 April 2014 (UTC)
"One Titan I booster engine with a new fuel pump was later ajso ground tested with LOX/H2."
[3]
Mark Lincoln ( talk) 18:03, 16 February 2016 (UTC)
There is no LR-87 and never was. The proper nomenclature is LR87. The designation system in use for jet and rocket engines excludes placing a hyphen between the letters describing the engine and the numbers indicating the serial acceptance of the engine.
Below is an document explaining the nomenclature in use since 1945:
"1. Representatives of the Navy Bureau of Aeronautics and of the Air Technical Services Command have agreed on the following general system of designating aircraft jet propulsion engines:
a. The system will be composed of two parts separated by a dash. The first part will consist of a letter(s) describing the general nature of the engine and a number designating the serial acceptance of the type. The second part shall consist of a number designating model under the basic type. The letters to be used in the first part of the designation are as follows with definitions as shown:
(1) J – Jet engine (without propeller)
T – Jet Engine (with propeller)
R – Rocket
PJ – Intermittent Jet Engine (Example: Buzz Bomb Engine)
RJ – Ram Jet engine
b. The odd numbers for the first and second parts of the designations will be used by the Army and the even numbers by the Navy. A particular engine will be identified by the same designation for both the AAF and the Bureau of Aeronautics. The number designating the engine type will begin with the number 30 in order to avoid confusion with some Navy airplane designations in which the new letters are used. Examples of this system are as follows:
(1) J31-1 – First Army model of first Army type of a jet engine (without propeller)
31-2 – First Navy model of first Army type of a jet engine (without propeller)
J31-3 – Second Army model of first Army type of a jet engine (without propeller)
J30-1 – First Army model of first Navy type of a jet engine (without propeller)" [4]
The USAF "T.O. 21M-HGM25A-1-1 Technical Manual Operation and Organizational Maintenance HGM-25A Missile Weapon System" defines the first stage engine in paragraph 1-243 (page 1-101) as: "STAGE I ROCKET ENGINE. The Stage I rocket engine, designated LR87-AJ-3, consists of two engine subassemblies."
[5]
The designation means Liquid Rocket #87 AeroJet second USAF version. The first USAF version was the LR87-AJ-1, the third USAF version LR87-AJ-5 was used in the Titan II.
Any comments before I change the name to the proper one?
Mark Lincoln ( talk) 02:23, 16 February 2016 (UTC) October 24, 2005 issue there was the last A
I decided this morning to search Aviation Week & Space Technology's archives to see when the "RL-87" first occurred. I searched for Aerojet LR87 and Aerojet LR-87. The results was interesting. The first mention of the LR-87 in AvLeak & Space Mythology was in the August 24, 1959 issue on page 27. "Models Show Configuration of Titan Engines." The caption mentions the "LR-87" and "LR-91." The last article in the AvLeak archive was "Titan, Adieu" covering the last Titan launch. The article in the October 24, 2005 issue reported "The flight also marked the last mission for the . . . Aerojet LR87 and LR91 series rocket engines . . ." In the intervening 46 years I found many mentions of the "RL-87 and LR87 (and LR91 & LR-91) their was no consistency. The same was true with the Atlas's LR89 & LR105 - worse actually because AvLeak usually used the Rocketdyne designation for the whole propulsion package (MA-3, MA-5, etc). I wonder if Aviation Week started the whole confusion?
Mark Lincoln ( talk) 23:04, 17 February 2016 (UTC)
The Titan 3M was about to be built when MOL was canceled. NASA considered using it as a vehicle for an enlarged Big Gemini 120 for space rescue. The The 3M would have had a quicker response time compared to the Saturn IB. "Extremes of estimated time interval to reach an emergency site in a low earth orbit are 4 hr. minimum and 144 hr. maximum. [6] Another scheme was to use it to boost refurbished Apollo Command Modules for space rescue. [7] NASA estimated Titan 3M would be cheaper, $15-16 million vs Saturn IB at $28 million. [8] The 7 section solid strap on was tested. [9] The modified LR87 had been successfully tested. [10] Ground Support Equipment was built [11] The fuel used in the modified YRL87-AJ-11 was "Alumazine 50 "a suspension of powdered aluminum in (gelled) Hydrazine.". [12] The last cited article also explains the "M" in Titan 3M. It stood for "Metalized." The new fuel required modifications to the YRL87-11 which are detailed in the "Stage I Engine Demonstration Testing" report.
This would make the LR87 unique in being the only Large Liquid Propellent Engine to have been fired with four different Oxidizer/Fuel combinations. Anyone have more information on the "almost flew" YLR87-11" for the Titan 3M (or IIIM)*?
Mark Lincoln ( talk) 03:30, 18 February 2016 (UTC)
I have located the patent for the metalized gel fuel. Patent 3,607,470 is titled "Thixotropic gelled liquid rocket fuel containing hydrazine and aluminum hydride coated with a semicarbazide copolymer" The patent says the inventor was James M. Lucas El Dorado Hills, Calif., and it was assigned to Aerojet-General Corporation El Monte, Calif.
A careful (and tedious) reading of "Stage I Engine Demonstration Testing" left me certain that the modifications were to increase thrust and man rate the engine. I have turned up no evidence that the modified YLR87-AJ-11 was ever fired with Aumazinen 50. There has been a lot of research going on with gelled fuels. [13] [14] [15] [16]
Mark Lincoln ( talk) 20:45, 22 February 2016 (UTC)
References
{{
cite journal}}
: Cite journal requires |journal=
(
help)
{{
cite journal}}
: |issue=
has extra text (
help); Check |url=
value (
help)
{{
cite journal}}
: Cite journal requires |journal=
(
help)
{{
cite journal}}
: Cite journal requires |journal=
(
help)
Hello fellow Wikipedians,
I have just added archive links to one external link on
LR-87. Please take a moment to review
my edit. If necessary, add {{
cbignore}}
after the link to keep me from modifying it. Alternatively, you can add {{
nobots|deny=InternetArchiveBot}}
to keep me off the page altogether. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true to let others know.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— cyberbot II Talk to my owner:Online 01:56, 25 February 2016 (UTC)
The result of the move request was: Moved. unopposed. ( non-admin closure) Dicklyon ( talk) 01:51, 11 February 2017 (UTC)
LR-87 →
LR87 – US military engine designation did NOT use hyphens
Petebutt (
talk) 12:08, 29 January 2017 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on LR-87. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 21:00, 9 May 2017 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on LR-87. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 06:09, 11 November 2017 (UTC)
As always with the Wikipedia some individuals are of the opinion that the actual designation is not acceptable because they prefer an imaginary one. Military rocket and jet engines have no hyphen between the letter and numbers. The J57 was never a J-57, nor the LR87 ever a LR-87. It has long been argued by self-appointed idividuals, who make up designations to suit their individual desires, that the imaginary world in which they live rules. This does not only happen with engine designations. The same fantasists also ignore the British official system for designating airships with a R separated from the number by a period. As they are self-appointed mavins there is no reasoning with their silliness. So the Wikipedia has designations which are absolutely wrong as demanded by individuals who believe that "reality" has to meet their deires rather than what is the truth. This is an interesting situation for what aspires to be an encylopedic resource.
Mark Lincoln ( talk) 22:26, 22 January 2022 (UTC)