# Recent content by LunchBox

1. ### 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. ### 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...

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...

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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### Compression gun

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