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Pages: (7) « First ... 4 5 [6] 7  ( Go to first unread post )

 Building an engine tutorial
Sumer
Posted: Jul 2 2007, 04:07 AM


You have way too much time on your hands ...


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Joined: 10-April 07



I'll take this into thought. I always say my writing absolutely sucks, so knowing that to edit and write again helps.

I'll throw an "Exotic Engine" guide together on the lesser known ones, Crower cycles, wankels, those.


--------------------
QUOTE
“I believe that the sound of racking the pump of a shotgun is universally recognized as ‘kiss your ass goodbye’."

Proudly Canadian
user posted image
QUOTE ("L3 Communications")
Well...next to Sumer's juggernaut of death, the MCA-7G.
Top
Falls
Posted: Jul 2 2007, 04:34 AM


Swamp Thing


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I also hope that the result of my effort with your tutorial ended in at least roughly what you had in mind.

It resulted in a much faster piece of work for me...I was able to skip bullshit and cut to the chase as it were.

I do mean it is a very good tutorial...it just needs to be made a bit more approachable and someone could realistically have a really work up in 15 min to half an hour...plus fifteen minutes for some quick research.
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Vault 10
Posted: Jul 3 2007, 10:01 PM


Unregistered









Well, so lifeboat engine issue is solved, the design is now about hull. However, I'll also need another engine - this time for a submarine.

Which of unconventional/advanced variants do you think would work well? I'm particularly interested in efficiency; it's to be ocean-going DE submarine.

Also, is classical twin V12 a good idea, or smth. else would be better? Such as opposed piston, or whatever. Efficiency and reliability are the priority.
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Macabees
Posted: Jul 3 2007, 10:04 PM


Freakin' Pimp


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I don't know if these offer any information you don't already know, but I uploaded them and are listed on my PDF file list.

http://files.filefront.com/Conventional_Su...;/fileinfo.html
http://files.filefront.com/Air_Independent...;/fileinfo.html


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[23:48] <Preston> I am an idiot of the highest power
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Sumer
Posted: Jul 3 2007, 10:21 PM


You have way too much time on your hands ...


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Joined: 10-April 07



I'd say go with AIP, but I'm not too well versed in it.
So off to read those PDFs I go.


--------------------
QUOTE
“I believe that the sound of racking the pump of a shotgun is universally recognized as ‘kiss your ass goodbye’."

Proudly Canadian
user posted image
QUOTE ("L3 Communications")
Well...next to Sumer's juggernaut of death, the MCA-7G.
Top
Vault 10
Posted: Jul 3 2007, 10:24 PM


Unregistered









Yeah, AIP for sure... but full AIP might be less efficient than hybrid, meaning surface+AIP.
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Sumer
Posted: Jul 3 2007, 10:27 PM


You have way too much time on your hands ...


Group: Admin
Posts: 6,060
Member No.: 8
Joined: 10-April 07



For sheer space savings, I'd say go for a pair of inline engines. For balance, and thus quietness, with weight savings, go for a V.


--------------------
QUOTE
“I believe that the sound of racking the pump of a shotgun is universally recognized as ‘kiss your ass goodbye’."

Proudly Canadian
user posted image
QUOTE ("L3 Communications")
Well...next to Sumer's juggernaut of death, the MCA-7G.
Top
Vault 10
Posted: Jul 4 2007, 10:52 AM


Unregistered









Well, of course, not inlines...
OTOH, AIP is really better - even with oxygen counted, submersion saves fuel. It kills the whole idea, though; I guess it's too late for DE.
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Sumer
Posted: Aug 6 2007, 07:15 PM


You have way too much time on your hands ...


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Posts: 6,060
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Joined: 10-April 07



Added an Appendix A of what not to do when building your engine design.
Will try to add one on the more unconventional engines some time.


--------------------
QUOTE
“I believe that the sound of racking the pump of a shotgun is universally recognized as ‘kiss your ass goodbye’."

Proudly Canadian
user posted image
QUOTE ("L3 Communications")
Well...next to Sumer's juggernaut of death, the MCA-7G.
Top
Trivalvia
Posted: Sep 4 2007, 08:49 PM


5% Armaments Designer


Group: Members
Posts: 112
Member No.: 169
Joined: 2-September 07



If I may pose a question:

What about alternate fuels and systems? ICly, Trivalvia is making a major push to "green-up" its transportation, both civilian and military, and what reading I've done suggests methanol might be the best fuel for the job. Methanol is biodegradable and water-soluble, remains liquid at room temperature and thus - in theory - could be used in conventional tankers, pipelines, and engines with only minor modifications.

However, I'm wondering what effect using methanol would have on engine power, and hence on engine designs, especially when developing engines and transmissions for military vehicles (thinking of tanks mostly).

Your thoughts?
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Vault 10
Posted: Sep 4 2007, 08:57 PM


Unregistered









They work - there's a number of good articles:
http://z4.invisionfree.com/NSDraftroom/ind...dpost&p=1978126

For effect, well, the alt-fuels work worse. But they work.


Methanol is a poison, though, its fumes included - keep that in mind.

As for engine changes, I'll leave that to Sumer.
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Sumer
Posted: Sep 4 2007, 10:57 PM


You have way too much time on your hands ...


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Joined: 10-April 07



The engine changes to run different non-petroleum fuels are really minor in their materials. Change valves, timing, pipes, to better facilitate the usually lighter and more volatile alternative fuels. They're not worth mentioning in any writeup. Any piston engine will run on pure ethanol with very minor modifications, the problems are generally the fuel system, storage and feed to the engine, as well as the lubrication systems, cooling systems, and so on. Methanol, being water soluble, is not something you want to even accidentally mix with the cooling water of the engine because then it's worthless and will stall your engine, whereas gaso9line will usually shrug small ammounts off, and diesel will simply ignore it unless the cylinder is flooded.

And of course there is the issue of combustion itself. Different fuels need different ways of combustion depending on how overengineered you want your engine. Compression is by far the most effecient, where it compresses the fuel-air mixture to the point of ignition, this is how diesel engines work. But consequently it's also the hardest, which is why gasoline cars don't use it. Gasoline and ethanol to name two, need a really high pressure of compression to just ignight, where diesel is fairly low. So you go from a clean and effecient compression ignition, to needing a spark to ignight the fuel-air and that means less will actually burn, and it will burn less effeciently because it will have to spread from a central point. This means less energy from a given fuel-air mass for more energy put in, and more waste fuel leaving the exhaust. Most military multi-fuel diesel engines because of this are dual mode, meaning they run a lower compression then normal but they also have backup spark plugs for running gasoline and such stuff. Or there is the alternative of an opposed cylinder engine, which will normally force you into a two stroke design which will degrade effeciency even more but allow compression ignition of virtually anything. I've read things about some Ukranian opposed piston engines being able to run on paper pulp of all things. A four stroke opposed piston engine is possible though, however it would be very tempermental because of the timing involved and hard to manufacture because of the needed cylinder design between the pistons at maximum stroke. It's just cheaper to go dual mode.

As for power, if I assume you're running a normal dual mode conventional diesel, then I'd off the top of my head say -10% power and torque for anything it's not designed to run, meaning anything but diesel. And I'd say -15% for the lighter fuels like ethanol or propane, or some jet fuels. But that's just a guestimate figure right there, actual numbers in the real world depend on a ton of things that I don't have the space to detail and will end up being ignored anyway for simplicity.

Rule of thumb here is this. Your fuel delivery systems will have the largest impact on performance with alternative fuels because they will dictate the mixture ratio, and it will not be perfect. It will generally be designed for one fuel, and all fuels have a different density, flow rate, and factors which will make the sludge. Biodiesel has a nasty habit of being thicker then regular diesel, and sludging easier, for instance, and will thus need larger routes to pass, which will affect negativly the pressures of the flow for gasoline or ethanol and thus you will end up with more fuel in the air then needed and less effecient burn.

It's all complicated, I just say go with a diesel engine, claim multifuel capability, and try never to use it unless you have to.


--------------------
QUOTE
“I believe that the sound of racking the pump of a shotgun is universally recognized as ‘kiss your ass goodbye’."

Proudly Canadian
user posted image
QUOTE ("L3 Communications")
Well...next to Sumer's juggernaut of death, the MCA-7G.
Top
Trivalvia
Posted: Sep 7 2007, 12:19 AM


5% Armaments Designer


Group: Members
Posts: 112
Member No.: 169
Joined: 2-September 07



So, if I understand you correctly:

1. The best engines to handle methanol will be based on the diesel engine model.

2. Any existing engines, diesel or otherwise, will have few changes to the engine, but many changes to other systems in order to accomodate methanol. Diesel would be easier to convert than standard piston engines.

3. Engines that are converted will yield less power than they would with their traditional fuel. Assume 10-15% reduction.

4. Methanol fuel delivery systems especially will need to be sealed - to keep fumes from poisoning the occupants and to keep water from wrecking the fuel mix.

Does that cover just about everything?
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Sumer
Posted: Sep 7 2007, 01:36 AM


You have way too much time on your hands ...


Group: Admin
Posts: 6,060
Member No.: 8
Joined: 10-April 07



It covers enough to be an issue for NS. There are probably a few minor things that would be a problem in real life, but I don't care enough to try and figure them out, and they won't come up in NS anyway.


--------------------
QUOTE
“I believe that the sound of racking the pump of a shotgun is universally recognized as ‘kiss your ass goodbye’."

Proudly Canadian
user posted image
QUOTE ("L3 Communications")
Well...next to Sumer's juggernaut of death, the MCA-7G.
Top
Sumer
Posted: Nov 22 2007, 09:47 PM


You have way too much time on your hands ...


Group: Admin
Posts: 6,060
Member No.: 8
Joined: 10-April 07



I'm going to be updating, rewriting, or simply adding a new section to this over this winter. I know many, or some, of you are going to look at some of the newer diesel engines comming out, such as the 890 series, or some of the other fancy things, and I want to update this to reflect both new technologies and ideas present in these engines, and the downsides to assuming you can get away with what news releases say about them. Just thought I'd let everyone know, and if you hyave any specific questions you want me to address regarding these in the next version, feel free to post them so I can address them.


--------------------
QUOTE
“I believe that the sound of racking the pump of a shotgun is universally recognized as ‘kiss your ass goodbye’."

Proudly Canadian
user posted image
QUOTE ("L3 Communications")
Well...next to Sumer's juggernaut of death, the MCA-7G.
Top
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