TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC
  1. TMC is currently READ ONLY.
    Click here for more info.

Aerospike Engines - And why they are not used...

Discussion in 'SpaceX' started by Grendal, Oct 22, 2019.

  1. Grendal

    Grendal SpaceX Moderator

    Joined:
    Jan 31, 2012
    Messages:
    5,661
    Location:
    Santa Fe, New Mexico
    Thorough discussion of the aerospike engine by Tim Dodd, the Everyday Astronaut, design and why it is not used. Should hopefully be interesting for those who enjoy the details and fundamentals of rocket engines. EA spoke with Elon about aerospikes in his interview at the Starship update in Boca Chica recently.

     
  2. Electroman

    Electroman Supporting Member

    Joined:
    Aug 18, 2012
    Messages:
    6,104
    Location:
    TX
    For lazy bums like me, without going into the minutia can someone post a one paragraph TLDR of what is Aerospike engine and how it fundamentally differs from the normal (Bell shaped engine?) one.

    Thanks
     
  3. Uncle Paul

    Uncle Paul Well-Known Member

    Joined:
    Nov 1, 2013
    Messages:
    6,105
    Location:
    Canyon Lake,CA
    Take away is that Aerospike has some exhaust control advantages, the cost to develop them is high and they are much more complicated, making them much heavier. The benefits in power are offset by weight, reliability and cost.
     
    • Like x 1
  4. Electroman

    Electroman Supporting Member

    Joined:
    Aug 18, 2012
    Messages:
    6,104
    Location:
    TX
    Thank you Uncle
     
  5. bxr140

    bxr140 Active Member

    Joined:
    Nov 18, 2014
    Messages:
    2,607
    Location:
    Bay Area
    A traditional nozzle can only be geometrically optimized for only one altitude/pressure, so total thrust is sub-optimal throughout flight except for one instant.

    An Aerospike better optimizes thrust performance over a wider range of altitudes and especially low altitudes, essentially using the changing ambient pressure and a bit of pixie dust to continuously self-adjust exhaust flow to an optimized geometry. The end result is better efficiency throughout flight and more thrust when you need it most--at low altitudes when the vehicle is the heaviest.
     
    • Like x 1
  6. Uncle Paul

    Uncle Paul Well-Known Member

    Joined:
    Nov 1, 2013
    Messages:
    6,105
    Location:
    Canyon Lake,CA
    Tesla says that since they are at low altitude for very little time, the complexity of the Aerospike, the extra weight and the lower reliability makes if not the best for them. Since they do not need the extra power, it is better for them to just use standard rockets. Bell housing with the Aerospike would be too big for them to gimble properly for return to Earth vectoring.
     
  7. RDoc

    RDoc S85D

    Joined:
    Aug 24, 2012
    Messages:
    2,719
    Location:
    Boston North Shore
    I'm still amazed that NASA chose the Venture Star, way back when, as the Shuttle replacement. Unless, of course, the whole point to the exercise was to NOT replace the Shuttle.
     
  8. Electroman

    Electroman Supporting Member

    Joined:
    Aug 18, 2012
    Messages:
    6,104
    Location:
    TX
    Thanks. This feels like kind of roughly synanomous to multiple gears on an ICE to to provide optimal torque at various speeds.
     
  9. bxr140

    bxr140 Active Member

    Joined:
    Nov 18, 2014
    Messages:
    2,607
    Location:
    Bay Area
    Exactly. Passive vs active aerodynamics is another one.
     

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC