Search results

  1. L

    Space elevator on Mars

    I've seen analysis that shows we could build a space elevator on the moon today, as in right now, with Kevlar. The only issues are getting that much Kevlar and supplies TO the moon (along with the fact that you would have to get TO the moon in order to "launch" on the space elevator FROM the...
  2. L

    Airplane pulling on the earth?

    Okay, folks... let's put this one to bed. Tide: Your momentum argument depends on what your reference system is... if it is the Earth, then yes, the Earth loses a small bit of angular momentum as the plane ascends, but gains it back when the plane descends. If you consider the plane to be in...
  3. L

    Simple homemade helicopter

    Herrbeta, always glad to help... Never say that... no project is ever useless. The most informative learning in engineering comes from actually DOing something. Anyhow... psf is "pounds per square foot" [lb/ft^2] Disk loading is a measure of the amount of thrust per unit rotor disk...
  4. L

    Simple homemade helicopter

    Okay... What you're proposing is a little ambitious, but from a very basic perspective, let's analyze hovering flight... You are going to want a relatively low disk loading... let's say 10 psf (lb*ft^-2). So in hover, thrust is equal to weight, so that makes the rotor area... DL = 10...
  5. L

    Contact between two rings or two cylinders

    Cylinder on Cylinder contact I recommend "Mechanical Engineering Design" 7th edition by Shigley, Mischke, and Budynas. ISBN: 007-252036-1 Section 4-20 has some great preliminary analysis tools and formulae for contact stresses of spheres on spheres and cylinders on cylinders (which I think...
  6. L

    NASA Space elevator feasibility; split from: NASA Announces New Launch Vehicle and CEV

    Ok, theoretically, that COULD work. However, the anchor would have to be ACTIVELY swung at a VERY high rotational rate requiring ENORMOUS amounts of energy to keep it spinning. However, this is what I like to call the difference between where physicists live, and where engineers live. Why...
  7. L

    NASA Space elevator feasibility; split from: NASA Announces New Launch Vehicle and CEV

    All orbits MUST lie in a plane which intersects the center of mass of the massive body (in this case, the Earth). An object in orbit about the north pole must pass over the south pole (and vice versa). The ribbon connecting the other anchoring mass would be wrapped around the Earth due to the...
  8. L

    NASA Space elevator feasibility; split from: NASA Announces New Launch Vehicle and CEV

    ... (Psst... just because the people work for a place who's name ends in "national laboratory" doesn't mean they have a direct pipeline to the wisdom of the ages. In fact, they are just as likely to be wrong as anyone else... I know... I work with these people from time to time.) ...
  9. L

    NASA Space elevator feasibility; split from: NASA Announces New Launch Vehicle and CEV

    I gots some numbers I just tried to post this and my browser crapped out on me... f'ing FireFox... anywho... here it is in condensed form because I don't feel like retyping it all... SkepticJ... your 'space fountain' is crap. Your grandchildren's grandchildren's grandchildren won't see it...
  10. L

    Does anyone have any liquid fuel rocket plans?

    I suggest you don't listen to Ki Man. HE can stand 50 feet away... I would stand at LEAST 50 m away. Remember... when the shuttle launches, there are the astronauts inside... and nobody else for 3 MILES! Cheers...
  11. L

    NASA Space elevator feasibility; split from: NASA Announces New Launch Vehicle and CEV

    Yeah, they'll have those right after they have satellites that can scratch your ass with a laser beam from space. Cheers...
  12. L

    Triangles, Bridges And Centripetal Space Habitats

    To a degree this could help. However, there is a limit to the angular velocity with which a ring can safely rotate. There are tangental and normal stresses that are imparted on a spinning disk. So a strut system could help distribute the stresses due to rotation. FYI: This is why you...
  13. L

    Compression gun

    Or you could do it the simpler way... more powder and a longer barrel... Cheers...
  14. L

    Calculator for Mechanical Engineering

    I personally use a TI-92 Plus. I bought it 6 years ago and still argue that it was the best $200 I ever spent. I use it for EVERYTHING! Cheers...
  15. L

    Motor selection

    Okay, as a good standard metric, the power output of a motor is proportional to the cube of the rpm. So your engine, as described, delivers 1 hp AT 1800 rpm. Using the cube metric, the engine should deliver about 0.005 hp at 300 rpm and 0.02 hp at 500 rpm. You are correct in that the power...
  16. L

    Personal exteriorless 'copter

    There are a few problems with this idea. 1.) Counter-torque - in order to keep the passenger from spinning opposite the rotor, the machine would need two counter-rotating sets of rotorblades. The gearing to do this would make the vehicle bulkier and heavier (thus being less practical and...
  17. L

    Solar Sail Spacecraft

    Yep. Looks like they did. http://www.cnn.com/2005/TECH/space/06/21/russia.cosmos.reut/index.html [Broken] The reason you can launch that much payload on a converted ballistic missile is due to the fact that the Russian's nukes were always heavier than ours (and why their manned rocket...
  18. L

    Best science fiction- your suggestions

    Wow... I can't believe nobody's mentioned Robert Heinlein yet. He is simply the grand master of science fiction writers... so on point, so sharp... messages so timeless and meaningful... what great sci-fi should be. Cheers...
  19. L

    News Depleated Uranium problem?

    Thank you for picking up on the sarcasm... I was wondering if I laid it on thick enough. And thank you for helping to prove my point. The only time a DU round vaporizes is when it... you know... slams into something at high speed. Considering anyone in the vehicle when it is hit is going to...
  20. L

    News Depleated Uranium problem?

    Wow Bob, that's interesting... but you know there's something even more pervasive that the military has been using even longer - dihydrogen monoxide. I mean, this stuff is everywhere! The government has been giving this to our troops for a long time. This stuff is shown to cause frequent...
  21. L

    Forced Vibration of a Cantilever Beam

    Ah... a subject near and dear to my heart... vibrations... The quintessential book on vibrations is "Fundamentals of Vibrations" by Leonard Meirovitch (ISBN: 0-07-041345-2) aka the 'Bible according to Meirovitch'. Exactly the problem you describe, he addresses... along with every other...
  22. L

    Fighting Sprit

    If by fighting sprit you meant 'fighting spIrit', then I'll answer... I think that both were extremely motivated and fought with equal vigor. However the Japanese (especially the Japanese Marines) were fanatically devoted to the Emperor, so I think I'd put them ahead. Why did Japan lose...
  23. L

    Why Harrier didn't success?

    A series of poor design decisions plagued the Harrier... 1) It had only a single engine to power EVERYTHING, including the ducts for vertical landing. So if the engine failed while hovering or landing, with no horizontal velocity to generate lift, that pesky gravity would bring them down...
  24. L

    WW2 era German 88 mm anti aircraft gun

    ... and it did it so wonderfully well... Cheers...
  25. L

    Designing a three wheeler

    You may want to check local laws... Three wheelers of ANY kind are not street legal in some US states (which I found out by being pulled over on a back road). Cheers...
  26. L

    Space Shuttle moon orbit

    Oh, PLEASE tell me you're joking! That movie ranks right up there with 'The Core' and 'Ghosts of Mars' as the movies that break the most laws of physics. Seriously, a group of friends and I made up a 'Mission to Mars' drinking game. Whenever they do anything that involves unsound...
  27. L

    Space Shuttle moon orbit

    Well... if money weren't an option, you could put a '72 Pinto Hatchback into orbit, to the moon, or to the stars... If you're asking what the LEAST expensive way to do it would be, then I'd have to say Launch-to-LEO-to-LLO-to-Land with hook-up and staging. That way existing launch vehicles...
  28. L

    What exactly is engineering?

    I could try my best to try and explain what engineers do, but I have found that in most cases when trying to explain something, someone else has done it much earlier and much more elegantly. So here it is: - Sir Eric Ashby As for what classes you'll be taking, I'll draw from the two...
  29. L

    Finding facts for fight

    If you go to NORAD's website (http://www.norad.mil/) they are constantly tracking and updating orbital elements on everything that they are able to track. The NORAD TLE (two line element) gives you all you need to create and propagate the orbit of any orbiting object. Here are a few...
  30. L

    Navigation Question

    The location of the poles vary throughout the year... by a few inches. And the rotation rate changes by a few tens of milliseconds throughout the year. So, no biggie... this tsunami is not a significantly huge terrestrial event (despite what the media is saying... and the chicken-littles...
Top