Silavite

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About Silavite

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    Rocketeer
  1. Propeller efficiency for a variable pitch prop can be approximated as about 80% out to around Mach 0.8, where things start getting funny with wave drag. I searched around a bit and found this with google. The theory is beyond my realm of understanding, but it features the propeller efficiency (η) of a Cessna 172's prop plotted against its advance ratio (J). Even if you were to model your prop based on this, you'd still need to find static thrust, which I have no idea how to calculate.
  2. SpaceX Discussion Thread

    Admittedly it's a bumper sticker, not a license plate, but... WE BRAKE FOR NOBODY
  3. What's your favorite rocket engine?

    RL60 Should have been the RL10's successor, but the engine never got a lease on life for reasons beyond me.
  4. SpaceX Discussion Thread

    I derped, the NOAA's Hurricane Center official forecast has Irma moving along Florida's East Coast, not far to the South. Some other models seem to agree with this track (GFS Model and ECMWF Model). Hopefully it stays off the coast. We won't have a solid of idea where it will hit (if at all) yet... right now it's a wait-and-see.
  5. SpaceX Discussion Thread

    Irma, as of now, is forecast to slowly weaken before it reaches Florida. http://www.nhc.noaa.gov/text/refresh/MIATCDAT1+shtml/061448.shtml? Also, Irma is forecast to stay well south of Cape Canaveral. Though, as with any forecast, it is subject to change.
  6. SpaceX Discussion Thread

    Perhaps you should drop by south east Texas, then. The facility in Brownsville better be built hurricane proof. (Yes, I know Harvey is only a tropical storm right now, and yes, I know it's supposed to hit North of Brownsville, but just sayin'.) Anywho, the launch window ends one minute before I get out of school. Curses, foiled again...
  7. SpaceX Discussion Thread

    Lucky me, band practice is in the evening today. Hoping to see this thing go! T-3 minutes now. EDIT Well that was a well timed post...
  8. A ninth planet?

    Surprised no one has posted these yet. http://www.findplanetnine.com/2017/06/status-update-part-1.html http://www.findplanetnine.com/2017/07/status-update-part-2.html
  9. SpaceX Discussion Thread

    Dang, thought it was rear loaded... oh well, shows what I know.
  10. SpaceX Discussion Thread

    The An-225 could carry it internally (just looking at dimensions and masses), but, uh, good luck on obtaining the thing... It might be possible to mount it on top of an aircraft and release it in a negative G push down, but that seems a bit risky, since the Dragon 2 has a much worse L/D than, say, the Space Shuttle Enterprise.
  11. SpaceX Discussion Thread

    What you're describing sounds very similar to the landing bags used in the Mercury program. Didn't the Manned Orbiting Laboratory plan to feature a hatch within the heat shield? I wonder how NASA/USAF planned to handle that.
  12. Perhaps they should ask the Russians to launch some Protons first?
  13. I understand that the Navier-Stokes equations are a set of equations that define the behavior of fluids and that a millennium prize is up for grabs for a complete solution to these equations. What I don't understand is what effects such a solution and understanding of these equations would have. How could it affect practical things like aircraft design, building design, and combustion dynamics? Could such a solution be vital to understanding these things, or is it simply (albeit impressive) academic? I know it's a bit presumptuous to ask for the effects a solution could have when we don't even know the nature of the solution, but this is something that I am quite curious about.
  14. I proposed something like this a while back. In the meantime, using a Kickback with the thrust limited works pretty well as a first stage.
  15. One engine vs clustered engines

    @Red Iron Crown hinted at this earlier, but as you increase engine size, volume of the chamber is scale factor cubed, but surface area is scale factor squared. This means that you have less area on the engine for regenerative cooling (relative to its volume). This is the reason that one can only make expander cycle engines such as the RL10 so big.