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Thread: Could the speed of sound be broken with electric AC ?

  1. #11

    Default Re: Could the speed of sound be broken with electric AC ?

    Quote Originally Posted by CubersWrist View Post
    Electric formula one is working to start in 2020
    http://airracee.com/

    "500mph will be no problem"
    I see M3 doable..as no compression present.

    Max Q occurs usually at FL 600. This design is still crawling 250-300 mph there.
    Last edited by Gonzales_LOX; 09-25-2018 at 07:58 AM.

  2. #12

    Default Re: Could the speed of sound be broken with electric AC ?

    Just saw your more in depth explanation. I retract the laugh. Sorry, been working for years to break 400 at Reno, and I forgot that you had specified at higher altitudes. It is a good point that electric motors don't need oxygen to breath/work, which Ben Rich said was a big design point on the U-2.

    So if you're going to build an all-out record breaking speed machine, then I say anything is possible with $$$. With all the complexity with the size and solar panels and detaching components, I don't see the next generation of airliner, but I do see a technology demonstrator or a speed record setter. Not sure what the rules are on breaking records, but with all the complexity this would take, it sounds simpler if you could get a tow/ride closer to altitude.
    "young" Thomas

  3. #13

    Default Re: Could the speed of sound be broken with electric AC ?

    Quote Originally Posted by CubersWrist View Post
    Just saw your more in depth explanation. I retract the laugh. Sorry, been working for years to break 400 at Reno, and I forgot that you had specified at higher altitudes. It is a good point that electric motors don't need oxygen to breath/work, which Ben Rich said was a big design point on the U-2.

    So if you're going to build an all-out record breaking speed machine, then I say anything is possible with $$$. With all the complexity with the size and solar panels and detaching components, I don't see the next generation of airliner, but I do see a technology demonstrator or a speed record setter. Not sure what the rules are on breaking records, but with all the complexity this would take, it sounds simpler if you could get a tow/ride closer to altitude.
    I am glad yo got it.

    Yes $$$ would be needed as the Solar Impulse II was a multimillion endeavour.

    One possible solution is a using a rocket when the M3 has been reached ( and feather the props )..as it is very light it could actually research the higher atmosphere too..I mean stratosphere.

  4. #14
    Join Date
    Jan 2018
    Location
    Derbyshire, UK
    Posts
    2

    Default Re: Could the speed of sound be broken with electric AC ?

    All I can think of when reading this topic is this -



    Rich

  5. #15

    Default Re: Could the speed of sound be broken with electric AC ?

    Quote Originally Posted by CubersWrist View Post
    Electric formula one is working to start in 2020
    http://airracee.com/

    "500mph will be no problem"
    Has there ever been a flying wing type of air racer ?

  6. #16

    Default Re: Could the speed of sound be broken with electric AC ?

    Not that I know of.
    "young" Thomas

  7. #17
    Join Date
    Dec 2002
    Posts
    1,765

    Default Re: Could the speed of sound be broken with electric AC ?

    Quote Originally Posted by Gonzales_LOX View Post
    Has there ever been a flying wing type of air racer ?
    Flying wing do not lend themselves to the low altitudes and high angle of attack / high G turns that are required for air racing.

  8. #18

    Default Re: Could the speed of sound be broken with electric AC ?

    Quote Originally Posted by Rich W View Post
    All I can think of when reading this topic is this -



    Rich
    As a child I really enjoyed playing with round the pole electrics. I was using really cheap 3V motors (Mabuchi RE-280SA-2865 I think )(30cents each) and put about 48V down the lines. Cooling holes I cut in the case really helped preserve the brushes. I totally blew away the competition who were using $20 motors when I turned up at model exhibition where they were flying. My speed models ended up with wings cut from ice cream containers and a spruce fuselage.
    It was also a way to give life to the built up construction scale models originally designed for rubber power.
    I would like to go back and try with brushless motors where the motors can survive much longer.
    Last edited by Colbourne; 09-25-2018 at 09:42 PM.

  9. #19

    Default Re: Could the speed of sound be broken with electric AC ?

    https://www.nasa.gov/centers/armstro...-068-DFRC.html

    This solar powered aircraft with 14 electric motors ( 2hp each) is able to fly at 170mph at altitude.

    https://en.wikipedia.org/wiki/Qinetiq_Zephyr

    The Zephyr uses 2 electric motors of 0.6 hp each and is able to fly at over 200mph at altitude.

  10. #20

    Default Re: Could the speed of sound be broken with electric AC ?

    Quote Originally Posted by CubersWrist View Post
    Just saw your more in depth explanation. I retract the laugh. Sorry, been working for years to break 400 at Reno, and I forgot that you had specified at higher altitudes. It is a good point that electric motors don't need oxygen to breath/work, which Ben Rich said was a big design point on the U-2.

    So if you're going to build an all-out record breaking speed machine, then I say anything is possible with $$$. With all the complexity with the size and solar panels and detaching components, I don't see the next generation of airliner, but I do see a technology demonstrator or a speed record setter. Not sure what the rules are on breaking records, but with all the complexity this would take, it sounds simpler if you could get a tow/ride closer to altitude.
    I do believe an electric aircraft could reach 500mph at Reno's altitude, although for how long will depend on the state of battery technology. Imagine an aircraft similar to the Mustang built of carbon fibre with improved aerodynamics. Similar flying weight but 80% of that being batteries. 4000kW motor. The Mustang has a weight of about 4000kg , so that would be a battery of about 3200kg. Batteries are currently around 250 Wh/kg so this equates to about 12minutes of full power usage. (if my off the cuff calculations are correct).
    What is the flying weight of Strega and its hp ?

    https://theconversation.com/teslas-b...-further-64765

    "Bosch’s battery company, Seeo, claims to have developed prototype batteries with an energy density of 350 Wh/kg (watt-hour per kilogram). In comparison, the Panasonic 18650 cells that Tesla uses have an energy density of just 254 Wh/kg. "

    "Two potential alternatives are sodium ion-based and possibly sodium metal-based batteries, which have higher energy densities than lithium ion batteries. One such prototype battery has demonstrated 650Wh/kg of energy density,"
    Last edited by Colbourne; 09-25-2018 at 08:57 PM.

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