Page 2 of 2 FirstFirst 12
Results 11 to 17 of 17

Thread: Supersonic with a propeller plane !

  1. #11
    Join Date
    Oct 2016
    Location
    Scurry, TX
    Posts
    1

    Default Re: Supersonic with a propeller plane !

    There are so many 'problems to be solved' for a solar powered a/c to a.) generate the power to get to 100K+ feet, b.) have the structural integrity to overcome even the much lower Dynamic Pressure forces.

    The first analogy to point to is the U2 with a 20:1 aspect ration and a Lot of thrust was treading lightly at 55-60K with a very small margin between cruise and stall speeds. What is your plan to convert solar energy to generate more Power Available, than Power required, necessary to even Climb to 100K+? Low wing loading is useful but Excess Power over Power Required is major factor for a.) ability to sustain level flight, b.) Climb in rarified altitudes, much less c.) drive the beast to supersonic speeds.

    BTW M=1 at 672 mph at 100,000 feet. Are you planning for a prop driven power plant or somehow converting solar energy to pure jet thrust>

  2. #12
    Join Date
    May 2015
    Location
    FINLAND
    Posts
    209

    Default Re: Supersonic with a propeller plane !

    I have no spesific plane, but I am able to conceptualize a 80 m spanning lifting fuselage plane that produces 1000 kw of power using 33% efficient panels. Props are 9-10 m dia...in other words huge...but rotate very slowly 300 rpm. Plane is 40 times lighter than similar size airliner.

  3. #13

    Default Re: Supersonic with a propeller plane !

    Quote Originally Posted by Gonzales_LOX View Post
    I have no spesific plane, but I am able to conceptualize a 80 m spanning lifting fuselage plane that produces 1000 kw of power using 33% efficient panels. Props are 9-10 m dia...in other words huge...but rotate very slowly 300 rpm. Plane is 40 times lighter than similar size airliner.
    Solar flux at ground level is 1050 watts/sq. meter, above the atmosphere its 1350 watts/sq. meter. Lets assume you're above 80% of the atmosphere and call it 1200 watts/m2 available at altitude.

    You want 1 megawatt of electric generation, which is 1300 horsepower, and you have 33% efficient cells. So you're getting 400 watts/m2 assuming the panels are perfectly perpendicular to the sun. You need 1.0e6/400 square meters of cells. That's 2500 square meters of cells... 27000 square FEET of cells. And that's at high noon. Solar cells weigh around 2 pounds per square foot at the low end... so your airplane has over 50,000 pounds of solar cells it has to carry, not even counting airframe, power systems, and the rest of the structure. Heck, lets say you get bare, conformal solar cells that only weigh 1 pound per square foot... 27,000 lbs in solar cells alone, nevermind wiring, airframe, skin, controls, motors, and you're going to lift it and make it supersonic with less than 1300 horsepower???

    Wanna re-think this a bit maybe?

  4. #14
    Join Date
    May 2015
    Location
    FINLAND
    Posts
    209

    Default Re: Supersonic with a propeller plane !

    I am also counting reflections wing area is 1500 m2. Batteries are 2/3 so total is 3000 kW.

    For time being I am making a 1/6 scale model of an electric twin which will be smallest twin and lightest motorized aeroplane ( ever ) in 1/1 scale..so this is POC.
    Last edited by Jukka; 11-09-2016 at 01:34 AM.

  5. #15

    Default Re: Supersonic with a propeller plane !

    Quote Originally Posted by Gonzales_LOX View Post
    I am also counting reflections wing area is 1500 m2. Batteries are 2/3 so total is 3000 kW.

    For time being I am making a 1/6 scale model of an electric twin which will be smallest twin and lightest motorized aeroplane ( ever ) in 1/1 scale..so this is POC.
    Batteries are even heavier than solar cells. I don't fault you for trying, but put pen to paper and do the math first.

  6. #16
    Join Date
    May 2015
    Location
    FINLAND
    Posts
    209

    Default Re: Supersonic with a propeller plane !

    I have done several calculations. It could go M2.6 without payload. Only electric aeroplane can cruise at 120 000 ft or above....and rockets of course.
    Last edited by Jukka; 11-10-2016 at 03:01 PM.

  7. #17
    Join Date
    May 2015
    Location
    FINLAND
    Posts
    209

    Default Re: Supersonic with a propeller plane !

    Swiss team is going to 80 000 ft with solar, but aiming later to 300 000 ft.

    https://www.google.fi/amp/www.theloc...olar-plane/amp

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •