Second thoughts about the nuke program

[tonyfedei]

I'm off to take my ASVAB and MEPS this coming Monday and am having second thoughts about the nuke program. I still want to enlist in the Navy even if it's not as a NUKE. I love math and science but I'm not exactly mechanically oriented, although I'm sure i could learn. The military websites have such vague job descriptions I was hoping some people on this site could help with some ideas as to what i might like doing in the Navy.

[Fermi2]

Sigh

[crusemm]

Can't say what you would like, only you can do that, however to help you make up your mind look here:
http://www.nukeworker.com/forum/index.php/topic,12184.0.HTML
http://www.nukeworker.com/forum/index.php/topic,14609.0.HTML
http://www.nukeworker.com/forum/index.php/topic,1890.0.HTML
http://www.nukeworker.com/forum/index.php/topic,16109.0.HTML
http://www.nukeworker.com/forum/index.php/topic,16466.0.HTML
http://www.nukeworker.com/forum/index.php/topic,10692.0.HTML
http://www.nukeworker.com/forum/index.php/topic,3821.0.HTML
http://www.nukeworker.com/forum/index.php/topic,3676.0.HTML
http://www.nukeworker.com/forum/index.php/topic,4089.25.HTML
http://www.nukeworker.com/forum/index.php/topic,1737.0.HTML

Now, as to whether Nuke or not, consider pro's and con's (these are personal, your mileage may differ)
Pro:
relatively rapid advancement compared to peers
eligible for bonuses
advanced training that equates to more college credits
more challenges (remember, relative)
generally get to work with some really good, intelligent, responsible people (again, relative)

Con:
REALLY long work hours
fewer "good deals"
still being at work performing shore power/shutdown as everyone else leaves the ship (and being in early for startups)
more shiftwork than usual
more challenges

Both lists go on ad nauseum, and I'm sure others will add their personal tidbits.  What it really comes down to is, do you feel up to the challenge of putting 100% into something for over six years in order to get some good training, some practical real world experience, and a chance to accomplish something useful with your life while still serving your country?  
Even if this is not the only path to do all of those things, it is the one that a great deal of good men (and women) have taken, and some of them have done really great things with their lives.  So Tony, think long and hard, make a decision, and commit to it 100%, whatever it may be, and you should do just fine.
Thanks for your service, welcome to Nukeworker, have nice Day
Peace Out -Matt

[HydroDave63]

If you like math and science but not mechanically inclined, I'd suggest OS , STS, RM or MT.

I saw all of those rates do well on my ship

[Fermi2]

I've seen some of the least mechanically inclined people I've ever known become Mechanics.

I was a prototype instructor with another MM2. He always rode a motorcycle to work. One day my former Sea Dad and I were driving home from A1W. We come upon Steve about 50 miles from the site. He's pushing his motorcycle. We pulled over to see if we could assist him and we found out he had run out of gas. He then revealed he knew he didn't have a lot of gas left when he road to work that morning but he figured if he road home real fast he'd make it quicker so he wouldn't run out of gas. I started laughing and stated well ya know when you double your speed your fuel consumption goes up roughly 8 times or so. He took me aside when we stopped at the gas station and said " Bru I didn't want to embarrass you in front of your former Sea Dad and best friend, but that power consumption thing only applies in Pump Laws"

Yep, lot's of Mechanically inclined MM's out there.

[co60slr]

I've seen some of the least mechanically inclined people I've ever known become Mechanics.

I was a prototype instructor with another MM2. He always rode a motorcycle to work. One day my former Sea Dad and I were driving home from A1W. We come upon Steve about 50 miles from the site. He's pushing his motorcycle. We pulled over to see if we could assist him and we found out he had run out of gas. He then revealed he knew he didn't have a lot of gas left when he road to work that morning but he figured if he road home real fast he'd make it quicker so he wouldn't run out of gas. I started laughing and stated well ya know when you double your speed your fuel consumption goes up roughly 8 times or so. He took me aside when we stopped at the gas station and said " Bru I didn't want to embarrass you in front of your former Sea Dad and best friend, but that power consumption thing only applies in Pump Laws"

Sounds like a great "ice breaker" for teaching GFES pump laws.  Are you practicing on us?  :-)

[Fermi2]

LOL I'd LOVE to teach GFES!

[still_in]

I started laughing and stated well ya know when you double your speed your fuel consumption goes up roughly 8 times or so.

Not true for internal combustion engines.  Carbureted engines require a a set fuel/air ratio for optimum performance. If your running anything less than optimum air intake you're wasting fuel. Given the time frame of A1W, the bike was carbureted.  So the guy was right to a point.

I'm sure I will feel the wrath of Broadzilla but so be it.

[Fermi2]

Not true. The rules of power consumption are finite. They are independent of the type of engine. To go from one speed to another speed will always follow the Laws Of Physics regardless of the engine or prime mover.

Mike

[Harley Rider]

Not true. The rules of power consumption are finite. They are independent of the type of engine. To go from one speed to another speed will always follow the Laws Of Physics regardless of the engine or prime mover.

Mike

Gotta agree with Mike on this one. Don't know if it is 8 times as much but agree with his premise. 

[still_in]

Agreed, but the heat input comes from more that just fuel. Its the air combining with the fuel plus energy input that creates the power.  The only way to get more air flow is to increase speed. This increase in air flow increases the mass entering the cylinder. More mass = more moles of air = more combustion for a given amount of fuel = more heat input. Neglecting ambient losses and friction, this heat in is converted into work out by the cylinder.  At the right fuel to air ratio you get more power.

[Fermi2]

Thank you, I bet if you do the math you'll find out it's around 8 times as much. The Pump Laws are derived from the laws of physics, they aren't simply laws invented to explain pump behaviour. They apply to any use of energy over a time period. One thing I love to do, is after my wife's car gets over 25 to 30 mph, is to predict the reading on her digital mileage remaining gauge after she raises speed. I'm always nearly dead on. Given the laws of energy consumption were first measured empiracally after the advent of reciprocating engines I'm pretty sure that apply to an internal compustion engine. After all they apply in Diesels. And the last I checked my wife's Saturn uses an internal combustion engine, not a turbine or pump

[Fermi2]

BS, all that does is allow the engine to use fuel more efficiently. I WILL submit a properly tuned Engine will burn LESS fuel at a given speed however any fuel used in a poorly tuned engine will be in ADDITION to that used in doubling the speed. It can never be less. You just proved you don't know what efficiency is. Or the proper use of energy laws.

[still_in]

I was simply showing that fuel consumption does not in fact increase by "8 times or so."  I do know how to use efficiency equations and energy laws, maybe not as well as you, but I do none the less. I did also study a cubic butt ton of IC engine analysis though.  

[HydroDave63]

One thing I love to do, is after my wife's car gets over 25 to 30 mph, is to predict the reading on her digital mileage remaining gauge after she raises speed. I'm always nearly dead on.

I'll bet the part that is unnerving is when BZ barks " new course and speed, 10 degrees left rudder, ahead standard..."

[Fermi2]

I was simply showing that fuel consumption does not in fact increase by "8 times or so."  I do know how to use efficiency equations and energy laws, maybe not as well as you, but I do none the less. I did also study a cubic butt ton of IC engine analysis though.  

It will always go up nearly 8 times minimum. All you did was prove you don't have a very good understanding of the subject.

[Fermi2]

I'll bet the part that is unnerving is when BZ barks " new course and speed, 10 degrees left rudder, ahead standard..."

LMAO!

[still_in]

I am unclear if you are saying that fuel consumption is independent of the mass flow rate of air.

It will always go up nearly 8 times minimum. All you did was prove you don't have a very good understanding of the subject.

This has been your argument for the entire debate.  Your original quote states that fuel consumption will increase by a factor of 8 as speed doubles.

I started laughing and stated well ya know when you double your speed your fuel consumption goes up roughly 8 times or so.

Put all the fuel mass you want in a cylinder there will be no combustion with out O2 and a spark.  This means air, so power output of an IC engine depends on air flow to the engine.  Same reason why your car runs like garbage if you don't change the air filter when it is dirty.  Air flow controls power of the engine = more air flow means more power for a set amount of fuel = more power in a frictionless environment = more speed. So if this Mechanic hit an optimum speed for the set fuel to air ratio of the carburetor on the bike, there would be an equal amount of fuel and air for combustion. Any more air would be an excess which means fuel economy would go down because the air intake could not provide enough mass of air, given size restrictions for the bike. So adding more more air would do nothing for performance given a set fuel flow given  by the carburetor.

All you did was prove you don't have a very good understanding of the subject.

I think you don't have a very good understanding... just returning the same courtesy you have shown me.

[number41]

HA!!!! I love this place!  This post just proves that I must have chosen the right profession for more than a few reasons:

1.)  NUKES ARE NERDS!!!
2.)  We'll argue with anybody over anything no matter how trivial if we think we're right.
3.)  We'll gladly take the opportunity to blast anybody who offers an alternate point of view.

p.s.  Navy EOOW is way harder than SRO, I am an MM3 and am getting out in a couple of months and want to be the PGM at an Excelon Plant, I won't accept less than $500k/yr and which plants are hiring right now?

Stit, stir, stir the hornets nest.....

[Preciousblue1965]

Ok first of all, they are both right in certain aspects.  Allow me to explain....

Internal combustion engine works on simple principle of you mix gasoline(in mist form) and air into a cyclinder, compress said mixture, ignite, and you have an internal explosion that forces the piston down, thus making car go.  To produce more power, you have to increase the compression or increase the fuel/air mixture.  

This is how turbos, superchargers, and NOS work(Superchargers and Turbos force more air into the cylinder using pressure, NOS splits the Nitrogen and O2 at high temperatures, thus allowing more O2 in the cylinder).  They increase the amount of air in the cylinder during compression.  The air itself does not increase the power, but the increase in air allows you to increase the amount of fuel you can put into the cylinder.  Too much air and you get "lean", too much fuel and you are wasting fuel due to incomplete burnoff.  You adjust the fuel mixture on carbs by "tuning" them, whereas EFI automatically adjusts this using computers(this is the reason that your car will run crappy if you ever disconnect the battery for extended period of time, it resets the computer and it takes a while for the computer to 'rebalance' your engine system to get to to peak efficiency).

So BZ is correct in that it takes a heck of a lot more gas to drive at 70 than it does at 30.  Anyone who drives a car can figure that one out.  Assuming identical gear ratio of 1:1 in say 4th gear, the gas pedal is much further down at 70 mph than it is at 40 mph. It take more gas to produce more power, which is why you never run your A/C when the fuel light is on.  However, depending on how far the gas station was, he could have theoretically "coasted" easier at a higher speed than trying to coast in at 20 mph.  

[JustinHEMI05]

[Fermi2]

No I am 100% correct in all respects. For any given power you HAVE to obtain a certain amount of BTUs. The BTU content of the fuel is fixed. For any given flow rate you need a certain amount of air. In an ideal system the mix is always perfect. The IDEAL , you double the speed you use 8 times the power, therefore 8 times the fuel. For any given engine design there's going to be a certain amount of fuel used. One the engine starts wearing, you need more fuel. Engines have to follow the laws of physics and thermodynamics. Take engine 1: At 30 MPH it's going to consume a certain amount of fuel. Take it to 60 MPH that amount goes up 8 times.

Now take engine 2: Give it a better compression ratio. I AGREE at 30 MPH it'll consume less fuel HOWEVER at 60 MPH it will consume 8 times the amount as at 30 MPH. It has to, that is unless you all have figured out a way to violate the laws of physics and thermodynamics.

[number41]

Maybe in his universe, friction doesn't exist?  Or, maybe friction is a linear phenomenon and the only reason it takes more (~8x) gas to double your speed is due solely to burn efficiency.  You know, if you drive an all elecric car, you don't have to worry about this to begin with...and it might result in Progress Energy raising the match percentage to my 401k.

[Nuclear Renaissance]

You just proved you don't know what efficiency is.

One might suggest that you don't know what "efficiency" is, since you are spending (wasting?) all this time arguing on an internet forum about ideal laws when the guy was on a real motorcycle...

[bradley535]

No I am 100% correct in all respects.

Bad news : You are 100% incorrect.

Good news : So is McLovin; so it's even.

I love the wonderful discussion of physics going on here, and on a level that I cannot even come close to repeating, at this stage of my learning. One glaring problem that even I can spot is that you are trying to apply heat engine laws to a combustion engine. Could one of you, please, try to explain how you came to the conclusion that BTU, or any other measure of heat energy, should be used in directly calculating the efficiency of a combustion engine. Heat generated is necessary only to excite the particles to cause expansion of gasses, after that the heat is undesired waste; thus the radiator was invented. Heat = bad in a combustion engine, and if they could figure out an efficient way to cause rapid expansion without the byproduct of heat, they would do so.

8x the amount of fuel to go 60mph vs. 30mph? Come on, does that pass the common sense check with you? Internal combustion engines have engineered efficiency graphs that show where they burn fuel in the most efficient speeds and gears. You can look these graphs up on-line or in any autoparts store, any car dealership, any... Well, point is, they are all over the place. Don't want to trust some crazy engineer who's dedicated his life to making those graphs, then run a few trial tests yourself. If what you said was true, then I could get over 200mpg out of my Subaru by dropping my speed to 30mph.

Now, before anyone goes off the handle and starts trying to tear this post apart, go out and check those graphs, take a deep breath, and realize that you are arguing from a point of view so theoretical that reality has no hold or lost your marbles.

[crusemm]

8x the amount of fuel to go 60mph vs. 30mph? ...If what you said was true, then I could get over 200mpg out of my Subaru by dropping my speed to 30mph.

This is in fact true, all other aspects being equal.  If you look at the advice for fuel conservation, one of the biggest things they say is to drive at the slowest speed you safely can, along with gentle acceleration and deceleration (yes, I know deceleration is -Acceleration).  One of the big reasons for the push to 55 mph back in the 70's and 80's was not safety like everyone was told, it was fuel conservation.  I'm not sure of the exact #'s, but off the top of my head I remember that they figured that limiting speed to 55 mph would cut national fuel consumption by a third (which was a huge concern back then).  It was not until 10-15 years later when gasoline was cheap again (relatively) that states started lifting speed limits.

[bradley535]

This is in fact true, all other aspects being equal.  If you look at the advice for fuel conservation, one of the biggest things they say is to drive at the slowest speed you safely can, along with gentle acceleration and deceleration (yes, I know deceleration is -Acceleration).  One of the big reasons for the push to 55 mph back in the 70's and 80's was not safety like everyone was told, it was fuel conservation.  I'm not sure of the exact #'s, but off the top of my head I remember that they figured that limiting speed to 55 mph would cut national fuel consumption by a third (which was a huge concern back then).  It was not until 10-15 years later when gasoline was cheap again (relatively) that states started lifting speed limits.

You failed to follow my advice of actually going out and looking at the graphs, and your post is a result of this. For one thing, you are talking about engine efficiencies of those made ~35-years ago. For another, a fuel consumption of 2/3 is VASTLY different than a fuel consumption of 1/8. For a third, those graphs I asked you to look at before posting would have shown the result of ~2/3 between 45 and 70mph (I would guess the difference of speed to efficiency is a result of those 35-years of engineering improvements). Those graphs will show you that fuel efficiency does drop off at higher speeds, but they will also show that the efficiency is not an exponential of speed. As a matter of fact, fuel consuption is most efficient at ~45mph for an average 4-door; however, the change to 60mph barely changes the fuel consumption per mile, and definitely doesn't change it by over 2x per hour, as would be required if you define efficiency as fuel consumption per unit time and kept with the 8x per doubling. If you had looked at those graphs, you would see that your post is actually agreeing with them.

Now I am certain that if you look at those graphs really closely then you can find a singular place where doubling the speed does cause fuel consumption to rise by 8x; but this will be at the very height of engine output and an event, not a constant that can be traced from every point along the engine's efficiency/output.

[deltarho]

Okay folks,
 
Homework for tonight: Using the Mechanical Energy Balance Equation, prove how much more or less energy it takes to go from 30 mph to 60 mph. Assumptions: uniform acceleration and friction is negligible. Show all work.

[deltarho]

There's no Applaud/Smite thingy that tells who did what to who...is there?

[Motown homey]

There's no Applaud/Smite thingy that tells who did what to who...is there?

There is.

http://www.nukeworker.com/forum/karmalog.shtml

[deltarho]

Oops!

[RDTroja]

Oops!

Hint: If you applaud after smiting, only the applaud counts... and vice-versa.

[spekkio]

I'm off to take my ASVAB and MEPS this coming Monday and am having second thoughts about the nuke program. I still want to enlist in the Navy even if it's not as a NUKE. I love math and science but I'm not exactly mechanically oriented, although I'm sure i could learn. The military websites have such vague job descriptions I was hoping some people on this site could help with some ideas as to what i might like doing in the Navy.

I think you have the wrong idea about what the Navy is about.

The Navy is an operational force. If you're looking for a job where you sit and crunch numbers all day, the Navy probably isn't going to be your deal. If you can do basic algebra and maybe a little trig, you can do pretty much any job in the Navy.

As far as being mechanically inclined, the Navy will teach you the skills you need to be successful in your rating. From there, it's up to your own work ethic to refine those skills. They may come easier to some people, but it's nothing that you can't overcome with some hard work.

Having said that, this thread can now return to arguing over whatever the hell it was you are all talking about. By the way, you fuel efficiency guys are ignoring the elephant in the room: time the engine is running. Engines burn fuel as a function of both speed and time, which is why car engines are most efficient in the 50-60 mph range...you get from A to B in the intersection between the time and velocity curves...anyone who took college calculus can probably remember doing optimization problems like these. So while BZ is correct that going faster will always use more fuel (although I'm not convinced on 8x as much being universal, unless you're claiming that somehow all vehicles have the same drag constant, gear ratios, and such), getting from A to B faster will result in using less fuel. Below the sweet spot, time dominates...above the sweet spot, speed dominates.

I did look up the graphs, and all of them seem to peak at two spots: 30 and 60 mph. Between those, the graphs tend to dip somewhat.

However, on graphs of fuel economy vs. engine RPM, the graphs are consistently most efficient in the 2-3000 RPM spot for most models.

[adrianI]

I wasn't mechanically inclined at all when I joined the Navy. As others have said the Navy will teach you whatever you need to learn. As far as the job goes it depends what nuke rate you become. If you have questions as to what life will be like as either PM me. One other thing to say, if you really aren't sure what that you want to join the Navy you can still say NO.