Call for collaborators - Mechanical Engineering Reference Guide for Add-on Authors

[Mattasmack]

In response to a list of ideas Cpt. Kipard posted a few pages ago, here are a few resources from older NASA docs that might be useful:

Rocket engines and tankbutt:

NASA SP-125, Design of Liquid Propellant Rocket Engines, is an early edition of Huzel and Huang's text on liquid rocket engine design. There are newer editions that are probably more relevant to modern engines, but this one is a NASA publication and is freely available. It can be found here: http://ntrs.larc.nasa.gov/search.jsp?R=19710019929&qs=N%3D4294129240%2B4294965930. It's a long document; some items of interest include Figs 3-2, 3-4, 3-7, 3-10, 10-10 to 12: biprop liquid engine layouts (both pump and pressure-fed); Figs 4-20 to 23: thrust chamber layouts; Figs 8-1 to 3: tank and engine configurations; Figures 9-1 to 5: engine mounting and interconnecting components; Figure 9-19: possible propellant duct routing for a gimballing engine; Figures 9-23 to 25: gimbals; Figures 10-26 and 27: photos of engine clusters.

Most of the information in this book is probably too fine-grained detail to be of interest to most, but if you want to make sure your engine is realistic by actually doing the engineering design ...

RCS placement:

NASA SP-8028, Entry Vehicle Control, located here: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19700019228.pdf. The figures in this monograph show the locations of RCS jets for control during re-entry for Mercury, Gemini, Apollo, and X-15 vehicles.

SEDR 300, Project Gemini Familiarization Manual, ought to be a good resource for this as well, but what I think is the relevant chapter (8, Guidance and Control Systems) is omitted from my copy as it was confidential at the time. I believe the whole thing is in the public domain now, but I can't find a version on any NASA servers. Perhaps someone else knows where to find a complete version.

Solar panels:

NASA SP-8074, Spacecraft Solar Cell Arrays, can be found here: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710028154.pdf. This one is mostly about the electrical and thermal design of solar cell arrays, but some Figures 14-16 show some mechanical layouts.

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NASA released a whole series of monographs on subjects related to space vehicle design in the late 1960's through 1970's, numbered SP-8xxx, which you can find listed in this catalog: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810013465.pdf. Generally each is focused on a particular design area (e.g. wind loads during ascent or solid rocket motor igniters), and so does not contain much big-picture information that a modder might be looking for to just determine how something should look. But they're worth knowing about.

[sumghai]

-lots of awesome stuff-

Mucho, mucho gracias - Cpt. Kipard and I will see to it that these are documented.

[CaptainKipard]

"four-bar linkage"

That's even a good addition on its own.

I think this is the precise name i've been looking for, and if not precisely this then something like. At least this level of abstraction. I'm not sure how to say this. If there's another name for a similar linkage that overhangs the way one of the arms does on the PLBD mechanism that would also be good to know. This would go under miscellaneous obviously.

Oh, by the way, I recommend following an alphabetical order for each entry, since it makes it easier to find things. Related entries can be prefixed with similar names/terms.

Agreed.

[sumghai]

"four-bar linkage"

That's even a good addition on its own.

I think this is the precise name i've been looking for, and if not precisely this then something like. At least this level of abstraction. I'm not sure how to say this. If there's another name for a similar linkage that overhangs the way one of the arms does on the PLBD mechanism that would also be good to know. This would go under miscellaneous obviously.

I definitely agree that the four-bar linkage should have its own entry under Miscellaneous, although I'll make a note that there are many, many variations on this depending on the specific application (no need to list all of the said variations).

[toadicus]

Heat transfer and refrigeration are critically important in aerospace engineering - hence the actual thread being named as the more-inclusive Engineer's Handbook rather than the Mechanical Engineer's Handbook. Your contributions will be most appreciated.

I just remembered I've got a C# port of a C library that does psychrometric calculations. I've only ported the inch/pound version because that's what we use at work, but I'll port the SI version soon and get it up to github. Then we can do air conditioning or theoretical meteorology.

[Teamwork]

Here's an another article on docking:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120015496.pdf

It focuses on the techniques to minimize air loss through docking nodes, discussing possibilities such as seal-to-seal connections as well as seal-to-flange ones.

From the same place, I found this one on nuclear rockets.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140009572.pdf

I haven't had enough time to read through it completely but it's a study comparing different nuclear rocket elements, specifically the reactor core; really interesting.

Edited April 18, 2015 by Teamwork
Updated Links

[CaptainKipard]

Here's an another article on docking:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120015496.pdf

It focuses on the techniques to minimize air loss through docking nodes, discussing possibilities such as seal-to-seal connections as well as seal-to-flange ones.

From the same place, I found this one on nuclear rockets.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140009572.pdf

I haven't had enough time to read through it completely but it's a study comparing different nuclear rocket elements, specifically the reactor core; really interesting.

OK, but how would you use those? The seal one is so esoteric as to be nearly useless for part makers, and the second one has schematics, rather than blueprints, and again that's not useful to people making models.

We should start with basics, like blueprints and cutaways.

I mean technical documents are fine, but they have to contain one of those two.

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Unless they're for plugin authors, in which case diagrams aren't as important.

Edited April 18, 2015 by Cpt. Kipard

[CaptainKipard]

I added the stuff from Mattasmack except the solar panel one because I couldn't find anything of interest to me. Who would like to take a look to see if they find something?

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I just remembered I've got a C# port of a C library that does psychrometric calculations. I've only ported the inch/pound version because that's what we use at work, but I'll port the SI version soon and get it up to github. Then we can do air conditioning or theoretical meteorology.

Are you joking or being serious? Also what does all that mean?

[architeuthis]

If diagrams and simple design criteria to use as references for drawing parts is mostly what you're after the whole NASA SP-8000 series of monographs are what you're looking for. Huzel and Huang which someone linked earlier is a part of that series. The monographs were generally short, a give a broad overview of a certain subject without being very much loaded with hyper discipline-specific terminology. A catalog of the series is here. The links are broken but all of the publications are definitely still up on NASA NTRS, you just have to search for them manually.

[Mattasmack]

I added the stuff from Mattasmack except the solar panel one because I couldn't find anything of interest to me. Who would like to take a look to see if they find something?

Yeah, that solar panel doc was a bit sparse. I had started writing it up before I realized how little was there, but decided to leave it in and let someone else make an editorial decision on it. Cool, I'm glad you found the others worthwhile!

That series of NASA docs is pretty dated by now, but I had them on-hand so I started there. I know they made a series of documents that gave nice descriptions of STS components (good for dimensions, RCS placement, etc.); if I can remember what they were called and find them again I'll post them as well. I'm sure they're in NTRS somewhere, but that's such a huge database that it can be hard to find anything specific.

[Pappystein]

I will be willing to help as well. However I am not an Engineer but more of a historian with an engineering background, basically an Airplane Nerd. I have a knack for getting accurate data out of innocuous texts. I can find the logic in they WHY things are done without all facts in evidence. This can be helpful for things like RCS placement. Also as my current series of articles cover, I have a nose for ferreting out changes from design to production that are not often documented.

The Photo of the cargo visor for the 747 is a perfect example. It is actually a derivative (in process, not exact design) of the McD C-17's visor. And yes a Nose cone that lifts above the cockpit for access to the cargo area is called a Visor. Some people will call it a Nose Cone when it is in flight position but a movable nose cone in engineering parlance is always a visor. One drawback to the term visor though is specific to the 747. The Early 747-100 aircraft did not have normal passenger seating on the upper deck. Rather the Upper deck was the location of a Bar/lounge or sometimes configured as a workspace/meeting place for professionals on the flight. Back in the early days some 747 Pilots and Crews called the Cockpit a Visor because it was ABOVE the passenger cabin. The Lockheed C-5 Galaxy, which flew for the first time around the same time as the 747 was the first aircraft to have a Visor that lifted above the cockpit. All previous aircraft that had nose access moved the cockpit with the nose.

[CaptainKipard]

Good to hear from you again Pappystein. If you're up for it I have a specific task for you, and that would be researching various types of aeroplane landing gear and their components. If not then let me know the kind of things you could do.

Also let me know whether you're qualified (and how) or a hobbyist.

[magnemoe]

I will be willing to help as well. However I am not an Engineer but more of a historian with an engineering background, basically an Airplane Nerd. I have a knack for getting accurate data out of innocuous texts. I can find the logic in they WHY things are done without all facts in evidence. This can be helpful for things like RCS placement. Also as my current series of articles cover, I have a nose for ferreting out changes from design to production that are not often documented.

The Photo of the cargo visor for the 747 is a perfect example. It is actually a derivative (in process, not exact design) of the McD C-17's visor. And yes a Nose cone that lifts above the cockpit for access to the cargo area is called a Visor. Some people will call it a Nose Cone when it is in flight position but a movable nose cone in engineering parlance is always a visor. One drawback to the term visor though is specific to the 747. The Early 747-100 aircraft did not have normal passenger seating on the upper deck. Rather the Upper deck was the location of a Bar/lounge or sometimes configured as a workspace/meeting place for professionals on the flight. Back in the early days some 747 Pilots and Crews called the Cockpit a Visor because it was ABOVE the passenger cabin. The Lockheed C-5 Galaxy, which flew for the first time around the same time as the 747 was the first aircraft to have a Visor that lifted above the cockpit. All previous aircraft that had nose access moved the cockpit with the nose.

Visor is an fitting name as it behaves as an visor and not like an nose cone who is removed then you want to access the inside.

As I understand the high cockpit of the 747 was selected because of its cargo version. It would give you an open cargo bay and an door as wide as the bay. The space behind the cockpit was for people following the cargo and spare pilots, it was too small to use as an effective passenger compartment. One the modern versions first class is typically put here, this also give the first class passengers the joy of calling the main deck the cargo compartment. Calling the upper deck an visor would however be plain wrong and an misunderstanding.

Did not know that some planes also lifted the cockpit even if I see that it should work.

Related why do planes with rear cargo hatch like C-5 and C-17 also have an front hatch too? I know military want an rear door because it let you airdrop stuff and bring your own ramp. For civilian use you prefer an front opening as its lighter, no ramp and you don't need to have an huge opening in the tail, you would anyway use special equipment to load and unload.

But why opening in both ends, has the rear door some downsides who make you want an front door? have seen they loaded massive stuff trough it.

[Pappystein]

But why opening in both ends, has the rear door some downsides who make you want an front door? have seen they loaded massive stuff trough it.

To use a Nautical term. Roll on Roll Off. As cargo/vehicles are moving off from one end, new vehicles and cargo can come in the other.

[magnemoe]

To use a Nautical term. Roll on Roll Off. As cargo/vehicles are moving off from one end, new vehicles and cargo can come in the other.

On ferries you use front and rear ports to not having everybody reverse on or off as this will take far more time, you empty them before allowing the next batch of cars.

On a military cargo plane you will use skilled drivers for this, the capacity is far smaller and you will use lots of time tie down the cargo before takeoff anyway. You will also need an ramp on location for driving up from front.

One reason might be that you can not use the airport cargo handling equipment loading trough the rear gate because of the ramp.

[toadicus]

Are you joking or being serious? Also what does all that mean?

I'm serious insofar as I do have such software, will port the SI functions, and will post it on the theory that more free code is better than less free code. I'm not entirely sure where it would be used, but weather mods could probably use it as they mature. I am imagine it as useful in a hyper realistic life support mod, too.

[Pappystein]

Good to hear from you again Pappystein. If you're up for it I have a specific task for you, and that would be researching various types of aeroplane landing gear and their components. If not then let me know the kind of things you could do.

Also let me know whether you're qualified (and how) or a hobbyist.

I have already started sorting my personal source material Visa-V Landing gears. Probably my best sources will be those relating to the XB-70 Valkyrie since after the failure of the Right main on AV-01 there was an in-depth study done on landing gear strength in relation to thermal heating of the structural elements of the landign gear (the leg, hydraulic dampeners bogie beam truss etc.)

Incidentally. RE your Skylon, I am curious as to why everyone assumes black rubber tires. To my knowledge no rubber compound that is black could be usable for more than 1 flight. Would suggest a Silver tire similar to the Valkyrie as the high metal content tire was designed for hundreds of uses. Not just 1. After each flight the US Space Shuttle got new shoes after all

[CaptainKipard]

Incidentally. RE your Skylon, I am curious as to why everyone assumes black rubber tires.

I guess because that's what official visualisations show. The manual doesn't mention the wheels at all unfortunately.

[Pappystein]

What information do you need about Landing gears? I have a ton of off the top of my head information and feel reasonably comfortable that I can dig out more specific information on short order. I do not have much in the was of specifics of a paticular landing gear unless it was a 1st of it's generation type Landing gear (The Boeing 90 rotation gear, the Kawanishi self lengthening gear etc from the original Shiden...)

Like I stated above, the most information I have directly on hand for modern "Bogey" style landing gears comes from the study of the collapse of XB-70 AV-1's landing gear.

[sumghai]

What information do you need about Landing gears? I have a ton of off the top of my head information and feel reasonably comfortable that I can dig out more specific information on short order. I do not have much in the was of specifics of a paticular landing gear unless it was a 1st of it's generation type Landing gear (The Boeing 90 rotation gear, the Kawanishi self lengthening gear etc from the original Shiden...)

Like I stated above, the most information I have directly on hand for modern "Bogey" style landing gears comes from the study of the collapse of XB-70 AV-1's landing gear.

I think diagrams / animations of the stowage mechanisms for the different types of landing gears would be most useful to part add-on authors.

[Pappystein]

I think diagrams / animations of the stowage mechanisms for the different types of landing gears would be most useful to part add-on authors.

Almost all of what I have is copyright material so I won't be-able to post much directly. And at lass I am not a model maker, unless you count SCALE models. However I can DESCRIBE a lot as well as finding documents on Wikipedia that are rights-less. In two weeks I will make a trip to my local Museum to take some High Quality (~3K res) pictures of Landing gears of various types. Not sure what aircraft I will find there that I can get close to the gears on (it has been a few years.) I am pretty sure I can get WWII era Korea era and both the F-14 Tomcat and SR-71/YF-12A gears. No Tupolev tumbling gears unfortunately.

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RE Skylon cargo doors.

http://i.imgur.com/aQJFJtE.png

The Two photos you provided show a tiny clue if you look carefully. This system is a series of angles right? Well the main bearing part (the Dark Grey L shape) has 3 bends on it not one like you would think at first look. Also the Door hinge is on the OUTSIDE and BELOW the door when the door is closed, meaning the open door's top edge is BELOW the closed doors lower edge by several inches even though they are the SAME door edge.

When I go to the Air museum I will see if they still have the space shuttle Engineer's book I donated years ago to them. if they do, I might just be-able to get you exact dimensions and angles of those parts. It has been so long I just don't remember what was covered in that book. The book predates Challenger by atleast 2 years but I remember a plethora of dimensioned drawings dealing with the various parts of the shuttle crew could work on or around.

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Something that would be nice for a Landing Gear mod, A Mk1 and Mk2 version of the F-111 main gear.

Not the best photograph but notice how the main gear seems to HANG. This landing gear has a solid plate instead of an axle between the two wheels (think a series of 4 parts to connect the wheels, two squares that each have a triangle on the opisite end. The joint where the square and triangle meet are hinge lines, a Hydraulic ram is attached to these hinges, pulling up to retract and pushing down to deploy. A control arm, not unlike that which holds the front tires of your car on and straight is attached at each end of the triangle right next to the wheels. This narrows the entire assembly as it rises up into the fuselage. The whole assembly is then covered by the drooping door in front of the main wheels.

http://upload.wikimedia.org/wikipedia/commons/d/dc/F-111B_CVA-43_approach_July1968.jpg <-- US Navy official Photo so no Copyright.

Edited April 24, 2015 by Pappystein

[CaptainKipard]

Almost all of what I have is copyright material so I won't be-able to post much directly. And at lass I am not a model maker, unless you count SCALE models. However I can DESCRIBE a lot as well as finding documents on Wikipedia that are rights-less. In two weeks I will make a trip to my local Museum to take some High Quality (~3K res) pictures of Landing gears of various types. Not sure what aircraft I will find there that I can get close to the gears on (it has been a few years.) I am pretty sure I can get WWII era Korea era and both the F-14 Tomcat and SR-71/YF-12A gears. No Tupolev tumbling gears unfortunately.

Descriptions are fine but diagrams and/or 3D animations are kinda important. Do you you're planning to do, and show me an example of what you can do with something that's least well documented visually, and we'll take it from there. I may end up doing 3D animations for the thread myself if you would help me to get them right.

When you make your trip I'd ask you to make as many photos as you can from various angle. This is from experience. I tried to make a 3D model of something once, and I took many reference photos from all the angles of which I could think, and it still ended up not being enough. There's always some detail that you miss.

When I go to the Air museum I will see if they still have the space shuttle Engineer's book I donated years ago to them. if they do, I might just be-able to get you exact dimensions and angles of those parts. It has been so long I just don't remember what was covered in that book. The book predates Challenger by atleast 2 years but I remember a plethora of dimensioned drawings dealing with the various parts of the shuttle crew could work on or around.

Cool

Something that would be nice for a Landing Gear mod, A Mk1 and Mk2 version of the F-111 main gear.

Not the best photograph but notice how the main gear seems to HANG. This landing gear has a solid plate instead of an axle between the two wheels (think a series of 4 parts to connect the wheels, two squares that each have a triangle on the opisite end. The joint where the square and triangle meet are hinge lines, a Hydraulic ram is attached to these hinges, pulling up to retract and pushing down to deploy. A control arm, not unlike that which holds the front tires of your car on and straight is attached at each end of the triangle right next to the wheels. This narrows the entire assembly as it rises up into the fuselage. The whole assembly is then covered by the drooping door in front of the main wheels.

http://upload.wikimedia.org/wikipedia/commons/d/dc/F-111B_CVA-43_approach_July1968.jpg <-- US Navy official Photo so no Copyright.

One thing at a time.

[CaptainKipard]

Pappystein have you been to that museum?

[Pappystein]

Pappystein have you been to that museum?

No RL has snuck up and bit me in the hindquarter. I am in a forced move mode ATM. Good news it has allowed me to buy my First house. Bad news, the home needs a lot of work before I can take a trip to the museum.

I did take a look at more pictures on the net and it looks like the part for your Shuttle door is a 3 bend for a total of 120 degrees part, not a single bend for 90 degrees. Since the Shuttle doors open about 120 degrees that makes sense. I hope that helps.

[CaptainKipard]

What does everyone think of adding a section with cutaways to the sticky?

Sorry for the large image.

-- Image removed because it's from a book not in the public domain --

Edited October 12, 2015 by Cpt. Kipard