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Thread: World Piston Engined Speed Record Attempt

  1. #31
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    Anybody any idea WHERE in Idaho this is happening...?Boise,Pocatello,Twin Falls ,Mountain Home,or where..? My guess is Poca....

  2. #32
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    It's taking place really out in the middle of nowhere, at the project sponsor's private ranch/airport.

  3. #33
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    I think Anywhere in Idaho is a bit in the middle of Nowhere,but it must be near Somewhere,but it`s nowhere to be found on the map....!

  4. #34
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    Possibly Challis, however I was raked over the coals for asking in a Voodoo fan page on Facebook.

    Hoping for better news on the attempt today
    "those who know keep quiet, and those who don't are frowned upon for asking." - snafu

  5. #35
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    They're live, I think I just saw the chase/camera T-33 take off: https://www.facebook.com/pg/PursuitA...=page_internal
    "those who know keep quiet, and those who don't are frowned upon for asking." - snafu

  6. #36
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    Yup, it's Challis, today's attempt aborted. He's back on the ground right now.
    If anybody ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me: It's all balls. RJM.

  7. #37
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    Won't be today or tomorrow apparently, the Merlin sneezed yesterday.
    If anybody ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me: It's all balls. RJM.

  8. #38
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    Further to ZRX61's post, Pursuit Aviation posted this on Facebook about 10min ago:

    UPDATE: Voodoo had some mechanical issues during yesterday’s attempt, so Steve-O safely landed it. He and the team are diligently working on it today and tomorrow. We’ll be sure to keep everyone up-to-date as we receive more information about a follow-up attempt. There will be a bit of down time, but hey… that’s the nature of making history! Blue Skies ✈️ -Pursuit Aviation Team
    "those who know keep quiet, and those who don't are frowned upon for asking." - snafu

  9. #39
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    In reply to Hooligan's mention of the prop - I would be very surprised if this is the one selected for an aircraft 'tuned' to 550mph, as the people behind the attempt have it. With that much twist the root section would be pushing the aircraft backwards with the effective parts at a suitable angle for thrust. This does look like a thin section high-speed blade, just not one optimised for flight with a tip rotational component of just 500mph and a forward speed of 550mph. Imagine the prop tips pitched at over 50 degrees to meet this - and then picture where the roots would be - essentially backwards.

    This is the right amount of twist for those sort of speeds.. (yes, they do turn half as fast - but they are twice the diameter!)

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    Unless they are running the prop ungeared? Then the angles might make sense - tip speed 1,200 mph.

    Interestingly, running normal .477 reduction gearing and assuming 3,000 rpm and a 3 metre prop the tips would be right up against Mach 1 at 550mph forward speed (around about 332 m/s combined, which is the nominal speed of sound at 6,000ft). No doubt one would be able to hear when that happened.

    Also I am interested in why they made the root thicker - this would make wing/fuselage interference worse. Are you sure this is the right way round? Looking at the image the tips appear thicker.
    Last edited by Beermat; 30th August 2017 at 14:41.
    www.whirlwindfighterproject.org
    It's all good. Probably.

  10. #40
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    Here's a prop on a supersonic aircraft - very interesting article: http://fighterwriter101.blogspot.co....8b-voodoo.html
    www.whirlwindfighterproject.org
    It's all good. Probably.

  11. #41
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    Well, every day is indeed a schoolday. Some very interesting figures here: http://www.machinedesign.com/recreat...imate-hot-rods

    It seems racing Merlins are expected to turn at 3,400 rpm, and the 'racing' gear ratio is .42. So prop speed is more or less the same as stock.

    The article says that race teams like to have prop tip speeds at an apparently optimum Mach 0.8. To do this at 550 mph would mean a prop diameter smaller than stock. So there ya go.
    www.whirlwindfighterproject.org
    It's all good. Probably.

  12. #42
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    Beermat, many thanks for your very informative reply!

    Hope the record attempt is captured on film with really good sound...!
    Last edited by Hooligan; 30th August 2017 at 15:31.

  13. #43
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    Had a good rummage around for images and it appears there is nothing unusual at all about the aerofoil. Just the usual internet spin-out from some random post. It seems it started with someone not associated with the project claiming they had recently scanned the 'new' wing with LIDAR. Hmmm.

    In fact she is little visibly changed from her purple incarnation, which already had a few adverse-pressure-reduction and shock-avoiding things going on. It would be very interesting to see what AP inc have changed to make 550 mph now viable with this airframe and engine. As HP111 said, one would expect something more radical than a paint job. Must be under the bonnet?
    Last edited by Beermat; 30th August 2017 at 18:51.
    www.whirlwindfighterproject.org
    It's all good. Probably.

  14. #44
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    For jets, shockwaves in the intake, particularly oblique ones reduce the speed to subsonic by the time it reaches the engine face.
    If I remember right, you also get a useful pressure increase as you cross the intake shock wave saving a bit of work for the compressor

    It's a long time since I did any fluid dynamics

    Richard

  15. #45
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    "Hope the record attempt is captured on film with really good sound...! " - it's definitely being captured, Pursuit Aviation (who I keep talking about and linking to) have a T-33 chase plane with nose-mounted Shotover camera for air-to-air (photos here and here, there's the webcam for the Facebook livestream (also by Pursuit Aviation), veteran air race photographer Scott Germain is there, and I imagine other moving picture cameras too.
    "those who know keep quiet, and those who don't are frowned upon for asking." - snafu

  16. #46
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    Hopefully they'll be able to fly soon, the weather here is beginning to get away from the sunny and warm streak we've had for the past few weeks.
    There are two sides to every story. The truth is usually somewhere between the two.

  17. #47
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    B`mat,have you found any info at all about the blade twist on the Bear? I have a suspicion that the front/rear props are different...maybe the Shack /Gannet likewise.The Bear looks about 35*,and runs about 750 rpm.
    Also worth thinkking about is that the aircraft `set-up will not be necessarily the same as for `fly fast,fly low ,turn left` at Reno,where one is pulling G fairly constantly where the aircraft and engine are subjected to torque and gyroscopic effects.In this case it will be`fly low-ish,fly fast,fly smooth and balanced`.To that end ,it may well be at a rear -biased C o G with tailplane adjusted/optimised for high speed (better to have an electric(dual) actuator) and maybe an adjustable CoG compensator.; for such an event I would have also considered having a `tuned length `exhaust` system to maximise engine performance...
    Would also be worth considering the advances in helicopter blade sections and tips such as Merlin/Lynx.
    Also in retrospect a look at the Prop on the S6B variants,fuel concoctions etc.

  18. #48
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    My reply disappeared. Short version is 5.6m diameter and 750 rpm. Twist slightly less than stock P-51. Cruise at 440 (faster than P-51) rotates at 480 (slower than P-51) combined 660. Tip speed exceeds Mach 1 in cruise above 40,000ft. Agree that rear set will be different - greater pitch - as need to bite into faster air.

    Re. S6 prop.. now there's a can of worms.
    Last edited by Beermat; 31st August 2017 at 21:21.

  19. #49
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    Latest news is it's back together, engine runs this afternoon, record attempt tomorrow.
    If anybody ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me: It's all balls. RJM.

  20. #50
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    For those not on Facebook, here's a quick pass during the test runs.

    Jason
    Jason Schillereff

  21. #51
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    Holy sh*t batman............

  22. #52
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    I am tempted to dig out the office speakers and scare the **** out of my colleagues!

    Did it years ago when someone emailed me a vid of Miss America going by very low and fast - the speakers happened to be turned up all the way to 11 () and the sudden burst of sound of a Mustang doing 400+kts made the finance team jump - and me!

    Good luck!

  23. #53
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    Here's a few videos from yesterday's test flight (8/31/17) shot by Voodoo crew member Bernie Vasquez.



    Jason
    Jason Schillereff

  24. #54
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    Nice videos and noise Jason - many thanks for posting

  25. #55
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    Sounds superb,Thanks for posting.Do you know what speeds these were ?

  26. #56
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    No, I haven't heard any numbers from the test flights in Idaho, just that they dove tested her before arriving to 565 with almost zero trim needed!!
    Jason
    P.S. The record run is set for Friday afternoon 9/2/17
    Jason Schillereff

  27. #57
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    Is that SATURDAY 2nd, or has it already happened? Confused.

  28. #58
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    It's set for today, Beermat.
    Give a man a fish and eat for a day. Give a man a fishing rod and he'll eat for a lifetime. Give a man religion and he'll die praying for a fish!

  29. #59
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    Good. Thanks - the website said Friday as well. I was wondering whether it will go so fast it will (have already) punch(ed) a hole in the space-time continuum.

  30. #60
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    There is a 7-8 hour time difference.
    Friday is 9/1/2017.
    Saturday is 9/2/2017.
    Afternoon say 1500,in Idaho ,is about 2200hrs UK TIME

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