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  • Users: faust9
  • In Mechanical Engineering
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  1. F

    Bearing failure rating? Simple rev counter?

    Bearings have data sheets. The max RPM, load limits and expected failure life are quoted in said data sheets.
  2. F

    Toyota Prius hybrid car

    It's been like this for 100 years. Cars have had computers longer than homes.
  3. F

    Toyota Prius hybrid car

    Never built.
  4. F

    Stress, no literally.

    Because you are using a differential cube. A differential cube is a cube whose volume approaches zero so it becomes a point while a plane---by definition---extends to infinity. You need to look at a volume because stresses in one direction will induce stresses in a the other two directions (3D...
  5. F

    Carbon fibres for flywheel

    You need to take a materials class IMO. You don't have understanding of fracture modes or fracture mechanics. Understanding fracture means you have to look at more than UTS or yield strength. You have to look at the are under the stress-strain curve. You have to dig up stress intensity...
  6. F

    Trying to design an engine

    I asked my question(s) for a reason. 1) H2 is a little hard to store. H2 molecules are small---small enough to migrate through a crystal lattice with some ease---and as such lopng-term storage can be a problem. Another problem with the size of the H2 molecule is a corrosion mechanism called...
  7. F

    Trying to design an engine

    Elaborate on the process for H2 production, transportation and storage please.
  8. F

    Maximum useage of a Potentiometer

    Pot's are not finite step devices like rotory switches. They continuously change which means you can amplify a signal from the pot to suit your desired operating range and not lose accuracy. If you used a 10K pot then you'd have just under 30 ohms/degree of travel thus 90 degrees would give a...
  9. F

    Calculator for Mechanical Engineering

    The battery died on my calculator during a Thermodynamics final(got an A in the class though) and I ended up using the table of logs in the back of the book to solve most of the problems by hand. I finished before most of the other students oddly enough. I thank my father for this because he...
  10. F

    Calculator for Mechanical Engineering

    EXACTLY! Anyone going into engineering should serously consider the Ti-86 IMO. The custom menu is great quick and easy to use along with the calc functions and Bob's points. PS. I hate 89's becuase they are little computers withouth the keyboards---unweildy.
  11. F

    Automobile Tire Problem

    PV=nRT Air is an ideal gas for the most part.
  12. F

    Calculator for Mechanical Engineering

    I absolutely love my YI-86. Harder to find but better for engineering than an 83. The 86 has a few built in calculus functions and diff-eq functions.
  13. F

    Oil between the piston and the casing manage to move with the piston?

    But the seating process only takes a few minutes to a few tens of hours depending on the ring composition and the ring facing material. The cross hatch remains after the seating process though not as pronounced as a newly built engine. Many piston/cylinder devices utilize an oil control ring...
  14. F

    Mechanics Of solids

    How did you make this leap? Sure, within a crystal structure or rather at a molecular level there is motion, but at a macroscopic level for a body to be in equilibrium the entire body as well as the differential bodies must also be in equilibrium. What that means is ME's disregard molecular...
  15. F

    The Let's talk about you do thread

    Long time no post---busy busy busy. I completed my BSME in '94 and then spent half a decade in US Navy. From there I went to work for an electronics firm (go figure). I did test software development and test fixture design/development. The test fixtures were used to automatically test high...
  16. F

    Difference between a fan and a pump?

    It comes from Bernoulli's equation. The equation is used in some form or another (v=k\sqrt{\Delta P}) for Pitot tubes, venturis, orifices and flow rates of gases across low pressure compressors like the air pump used to feed additional O2 into the exhaust stream---at least in the part of the...
  17. F

    Difference between a fan and a pump?

    All fans are pressure generators too. The motive force for the flow through a fan or blower is a pressure difference. The magnitude of pressure generated by a fan is less than that produced by a centrifugal pump moving water or a positive displacement compressor; however, fans still produce a...
  18. F

    Difference between a fan and a pump?

    Well I guess we'll disagree here then because I've worked in many places where the purpose of the 'pump' was to create 'flow' as in the feed pump for a steam generator. Yeah, the pump had to boost the pressure to the operating pressure of the S/G but more importantly, the pump had to match the...
  19. F

    Difference between a fan and a pump?

    A misnomer. A compressor.
  20. F

    Difference between a fan and a pump?

    A fan is a compressor and a compressor is a device which moves fluids in a gaseous state. A pump is device which is used to move a liquid. Both devices work in similar manners in that one design can be used to move a liquid or a vapor---a screw type device for instance is used in...
  21. F

    Another question

    The mass flow rates of the outer and inner fluid are the same though so inertial differences are negligible.
  22. F

    Another question

    Yes, but the 'mixed' flow will occur within the smaller pipe not in the common duct.
  23. F

    Another question

    What do you think happens?
  24. F

    Submarine or Stealth bomber

    Don't forget the sound deadening material used to cover the sub(it's as advanced as RAM on the stealth airplane) and the screw is designed to do more than minimize cavitation. The shape also has a lot to do with the acoustic profile of the sub (banded or not, number of blades, how clean it...
  25. F

    Unsteady Air Conditioner

    Where did you get those numbers from? I can prove my statement by looking at the T-s, P-T and a P-v diagrams. The numbers you have above are for a supercooled liquid. When you compress a supercooled liquid--again, assuming it is adiabatic---you move up to intersect the new pressure curve(on a...
  26. F

    Unsteady Air Conditioner

    The short answer is one step at a time. First, you have a misconception: the refrigerant will be in a two phase condition at some pressure depending on the total mass of R11 in the system and the initial temperature of the system. There will be a liquid region at the lowest point and a...
  27. F

    Books on the field of Mech. Engineering

    You can start with a book called Mechanics by JP Den Hartog. It's a Dover book and it run about $15. It's actually a very good book IMO and you'd be hardpressed to find a modern text that is better. Modern texts are printed on better paper and have more pictures but the concepts presented are...
  28. F

    Modding My Road Bike for Aerodynamics: Ideas & Suggestions?

    I use Fluent( ) though it is by no means easy---very powerful though. I've played with solidworks Cosmos ( ) it's fairly easy to use and is integrated rather nicely into solidworks. There are some F/OSS...
  29. F

    Modding My Road Bike for Aerodynamics: Ideas & Suggestions?

    What do you mean by model? Are you asking about CAD or CFD?
  30. F

    Intake manifold runner design

    I was hoping someone would catch that :biggrin:
  31. F

    Intake manifold runner design

    You will need access to an engine dyno to determine the optiman runner length/shape and optimal plenum shape. Intakes and exhaust systems are voodoo black magic throw the chicken bones pieces of an engine and need to be designed as such. You could do Helmholtz...
  32. F

    Negative pressure supercharging -comments?

    Ha, Ha. The device in question is already on your car more than likely. It's called EGR---Exhaust gas reflow. [edit]Whoops---didn't see the technical manual. I misread the way it was supposed to work... It's still snake oil. This is not the first time I've seen this type of system nor will it...
  33. F

    Manifold design

    The problem with large plenum designs is throttle response gets slower. This is especially noticible on FSAE cars because the engines used there are around 600cc spin at about 10,000 to 15,000 rpm and have to breath through a 20mm restrictor. With large plenum intakes you get a very pronounced...
  34. F

    Manifold design

    The reference guide: [Broken] A lot of manifold design in CAD boils down to using pipes. You decide on a path and tell your CAD software to route a pipe of x diameter and y thickness along the path...
  35. F

    Air Compressor Oil [Broken] Ask the source.
  36. F

    Automobile Cooling System

    Electronically controlled engines tend to show this kind of cause and effect failure more so than carbed engines. A sensor failure (as Cliff indicated) can and will manifest itself as a secondary problem. Do you have a check engine light lit? Any excessive divergence between required fuel and...
  37. F

    Gear Design Problem

    If you use a 20( or 14 for that matter) degree contact angle you are much more likely to find your gears as an off the shelf item. If you plan on taking this to production then cost should be an issue. Having a custom gear cut or cast for a single product line adds to costs. Actually...
  38. F

    Optical Encoders

    You should be able to do this with any cad program. What pattern do you want? How many pulses? If you supplied that I'm sure someone here would whip something up for ya. If you can't afford a CAD package look into some of the free one's. What you'll need to do is draw a single cut out and then...
  39. F

    Tuning fork to stop engine vibration?

    Don't use teflon and thread lock together. That's like trying to superglue and egg to a non-stick pan. Don't bother with soft bushings of any sort. Use Al inserts if things are loose otherwise just bolt everything together. You should have a bolt distributor somewhere in your area if you can't...
  40. F

    Failure of a connecting rod

    I'm still not sure if you threaded the con rod. I'll reiterate my first suggestion--loose the threads. Next, from what I see is the rod is going into tension where the rod and cap meet. That can be eliminated by increasing the con rod bolt pre-load(another reason not to thread con rods is you'd...
  41. F

    Failure of a connecting rod

    Cracks propogate along planes of max stress and do so from pre-existing flaws. Bolt threads are man-made pre-existing flaws--each of those threads is a failure waiting to happen. That is why connectin rods are not threaded. Rod bolts are splined along their axis, or they have a very round high...
  42. F

    Help me find a bolt

    Thanks for the response. The bolts will be used in a differential on a race car. We can get away with standard graded bolts; however, it is frowned upon and requires more testing on our part to prove the bolts we use will survive. NAS bolts have had the testing done already and enable use to...
  43. F

    Help me find a bolt

    Help me find a bolt... Ok, I'm lookng for a bolt distributor (as close to the Detroit area if at all possible) who sells NAS/MS bolts. Specifically, I need 8 MS21250-05056's. I know this is an odd request, but I've searched high and low for said jewels but the distributors I've dug up thus...
  44. F

    Carbon fiber kits

    Who's at fault if an croth-rocket owner is doing 200MPH in the first place? Secondly, The plastic fairings are fairly flimsy to begin with. Third I can almost guarantee that the replacement parts are not "engineered" but rather knock-offs of the original plastic parts. Fourth, CF is really a...
  45. F

    Solar Panel Deployment

    There is no "technique". Each system is designed around some predefined goal. Weight, size, lifespan, usage, etc are all taken into account and then an industrious ME or AE sits down and figures out a way to make a system work within the design constraints. A system may use cables or screws or...
  46. F

    Neumatics, Pumps, and suspension.

    If you know the weight of the objects you need to lift then gears would probably be the easist route. Pneumatic systems take a bit of planning(solenoid valves, more batteries to power said valves, more software to control said solenoids, etc). Add a counter weight to your lever arm like this...
  47. F

    When I turn, the car hops up and down.

    Tank tracks? Have you thought about those? Also, do you have the grabber arm built into to front of your vehicle or did you build it so it attaches between the rear wheels or behind the rear wheels? Attaching behind the rear wheels a little will make load distribution a little easier...
  48. F

    When I turn, the car hops up and down.

    You could use a smooth plastic "nub". A little nylon sphere on a stick would work well(I've seen a lot of sumo-bots with these). Or you could go crazy and install a handfull of 3-axis motion sensors and a complicated algorythm to continually balance your bot(like the Segway).
  49. F

    When I turn, the car hops up and down.

    Why are you turning the back wheels in opposite directions?
  50. F

    What causes wheel to go in straight motion?

    Well, you can start by not turning the wheels. I don't understand your problem. What are you doing to not make your car go straight? Are you turning the wheels? Did you make sure the wheels were alighed? Do you have a weight distribution problem?