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Dreamliner hits 801 mph with 200 mph tailwind

Discussion in 'Everything Else (off topic)' started by TurboDiesel, Feb 21, 2019.

  1. TurboDiesel

    TurboDiesel

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  2. Jack Straw

    Jack Straw

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  3. stuckinthemuck

    stuckinthemuck

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    Not that hard to do when you have a 150 knots on the tail... I imagine they pushed the power up just a bit to make it up to that speed though.. A lot slower going the other way...

    2F822E57-3FC5-4FD5-8750-7337E48EB066.jpeg
     
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  4. stuckinthemuck

    stuckinthemuck

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    Looks like the wind was more like 230 mph on Monday. That’s 200 knots (speed measurements planes use). I think the crazy thing is that the winds it took to get the Dreamliner up to that speed at an altitude of 35000’ are the same winds that were experienced on the top of Mount Washington in 1934 when it recorded the highest wind speed ever recorded on earth. When that jet stream drops down, it does so with a vengeance!!!
     
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  5. stuckinthemuck

    stuckinthemuck

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  6. Backwoods Savage

    Backwoods Savage Moderator

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    I wonder what it would be like on a bicycle to have a tailwind like that?! :bug:
     
  7. billb3

    billb3

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    It would be quite cold.
     
  8. billb3

    billb3

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    Shame that was just ground speed and the plane was still doing its usual 500 or so mph. Stall and flight control still have minimums despite a tail wind.
    Now a controlled dive on the other hand ..... 800 MPH would be news and social media would be aroused.
     
  9. stuckinthemuck

    stuckinthemuck

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    If you could keep upright and not smoke the wheels on the pavement or burn up bearings, I imagine the ride would be quite exhilirating. Your pedals wouldn’t work without a significant change in gear ratio as you physically couldn’t pedal fast enough. So depending on what kind of sleek cycling suit you were wearing, the force of the wind at your back and drag generated by your clothes would determine your terminal ground speed. Theoretically, I imagine that would be 30-40 mph below the wind speed. Just think about what wind speed it would take from a standing stop to get you rolling on the bike and that’s about the speed you’d stabilize at relative to the tail wind. So in theory, 190-200 mph with the wind at your back 30-40 mph. On a warm day, very little wind chill at all!! Could we call myth busters and volunteer your services?
     
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  10. Backwoods Savage

    Backwoods Savage Moderator

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    I remember on RAAM with 50 mph tail winds many of the guys were hitting 50 mph on the bikes and loving it! Of course they had some big gears made for that speed. That was the same year, if I remember right when Glenn Druery from Australia was clocked over 80 mph in Colorado. He was riding a specialized bike and his but was only a few inches off the pavement. It was wild! He was telling me that he once got stopped by a cop and was told he had to slow down because he was speeding. Glenn begged him for a ticket but the cop just laughed. It would certainly have been a nice trophy for riding a bicycle. I think he said he was around 50 mph at the time and was in training.
     
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  11. Screwloose

    Screwloose

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    I have a dumb question. At that speed what happens if you suddenly leave the jet stream ? Since the momentum of the plane is still going the high speed would it not experience a period of the actual higher speed.
    Seems to look worse typed out than it did rattling around in my head.
     
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  12. stuckinthemuck

    stuckinthemuck

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    So it really depends on which way you were going relative to the high windspeed. A sudden change in windspeed creates a shear that causes turbulence... how that is felt is determined by the size of the airplane, speed, configuration and a few other factors.. when going from a high headwind to a lower headwind, the planes indicated airspeed (IAS) initially drops even though the groundspeed begins to increase. The opposite happens when going from low headwind to high headwind... indicated airspeed is what keeps a plane in the air so you will find that planes fly faster approaches (faster indicated even though the ground speed may be slower) when there is a chance for loss of headwind (or gusty winds) on approach to landing. The 787 maxes out at 85% of the speed of sound or Mach .85. So when going from low headwind to high headwind, despite the possibility of getting rocked around by some turbulence, there’s very low possibility of experiencing the stresses on the airframe associated with approaching the speed of sound.. Airplanes (IE the pilot’s flying them) generally slow down when turbulence is expected... I have no idea if I answered your question. ;)
     
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  13. Screwloose

    Screwloose

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    You most certainly did !! Thanks for taking the time. Somehow I knew it would be you educating me.
     
  14. Paul bunion

    Paul bunion

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