Raptor Composite Aircraft

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Dexacare, Mar 28, 2016.

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  1. Aug 25, 2019 #1341

    pictsidhe

    pictsidhe

    pictsidhe

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    And no breather for that casing. It has oil going in, a drain and currently no leaks. Anyone else see an issue there?

    Ross, Peter said in a recent-ish video that he didn't calculate that 1800lb as he didn't know how to get solidworks to do it back then. He just looked at similar aircraft for an idea.
     
  2. Aug 26, 2019 #1342

    Venom

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    Unfortunately none of us know what the thing weighs now nor where the CG is. But if he is talking to the DAR then I would bet that he knows exactly what it weighs and where the CG is. And I would guess that you are correct. With more weight going way aft and Jeff building a specific chamber for ballast up front, either the ballast stays or the battery gets jockeyed.

    On a different note....Peter indicated that he was going to run a tied down static thrust test. If i understood correctly this test on a propeller driven airplane is of nearly no value. Is that not true?
     
  3. Aug 26, 2019 #1343

    BJC

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    Such a test can be useful for setting the high RPM stops in the propeller.


    BJC
     
  4. Aug 26, 2019 #1344

    rv6ejguy

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    It seems very odd that Peter hasn't showed the weight now on a new vid since he shows everything else. With the DAR inspection imminent, he'll have to have that information. Peter's been repeatedly asked to reveal the new weight in the YT comments for months now with no response.

    Any time spent running the engine at high power on the ground will be useful to uncover potential issues. The thrust test will make for a good video too- a little more interesting than putting sun visors in...
     
  5. Aug 26, 2019 #1345

    Hot Wings

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    Is that kind of like the inverse of the law of diminishing returns? "Well it's already 1400 pounds over weight. What is another couple of pounds from the sun visors going to make? After all that is only 0.14% of the problem."
     
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  6. Aug 26, 2019 #1346

    pictsidhe

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    It needs weight forward. Those sun visors and ridiculous honeycomb pedals aren't as big a penalty they seem. Not as efficient as weight in the nose, but part way there. What he really needs to do is get weight out of the back.
     
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  7. Aug 26, 2019 #1347

    flyboy2160

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    After the elastomer damper fails again, I predict the IT Peter fix will be.........replacing the elastomer engine mounts with solid aluminum. Then maybe he'll add elastomer mounts between the engine mounting frame and the airframe. That'll fix it!
     
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  8. Aug 26, 2019 #1348

    rv6ejguy

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    I am really surprised that his engineer friend Mark hasn't said something about this aspect of the PSRU design and the fact that the new coupling isn't rated for the rpms or torque of this engine. Does he know know all this? Has he told Peter but Peter doesn't listen?
     
  9. Aug 26, 2019 #1349

    FarmBoy

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    Yes, TV should be analyzed with any engine. A TV reduction coupling or dampener could potentially be required and would, of course, add a few pounds (though unlikely enough to offset size/weight reductions). Such a coupling may be desirable for even a V8 engine for both TV improvements and potential protection from a prop strike.

    You are certainly correct that reliability/durability should be at the forefront, especially for aircraft bound items. While HP/L might be an interesting generalized value, there are certainly many engines with << 100HP/L with very poor reliability and likewise high reliability engines > 150HP/L. What matters most is the design of an engine and what its weak points are from a durability/reliability perspective. As with a diesel, higher HP per volume and/or per revolution makes the design of pistons, cylinders, valves, wrist pins, etc. more important. DeltaHawk found this out the hard way as at least one of these items (wrist pins) was the cause of premature failure requiring engine redesign. All of these items are designed for at least 350 HP in the 2.3L ford engine targeting automotive use and at least 100,000 mile service - this corresponds roughly to a 2-3,000 hour TBO. It also depends on what you mean by long-term - while durability between TBOs is unarguably paramount, a lower life-cycle cost engine that can meet its TBO is just as viable as a "more durable" engine depending on use case (and wallet).
     
  10. Aug 26, 2019 #1350

    FarmBoy

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    Do you have the specs on the new lord coupling handy? I remember looking it up and finding it wasn't the one someone here referenced.
     
  11. Aug 26, 2019 #1351

    flyboy2160

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    The videos look like their DynaFlex LCD, which are used for for truck trannies, etc. If so, it won't make a difference which one he picked: the dynamic alignment specs look pretty tight. I suspect these are intended for use between fixed components, not in the wobbly installation he's got.

    (I designed one-in a long, long time ago at work, but I've completely forgotten everything....except that the parts were nominally fixed and that I needed the consultation with Lord engineering.)
     
    Last edited: Aug 26, 2019
  12. Aug 27, 2019 #1352

    Scheny

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    It should be easy to locate Marc using the comments from the videos. Would be the easiest way to tell Marc what state of the arty for a prop drive looks like. Seems at least he has some influence on Peter.

    I admit, the first iteration of the reduction gear in my boat failed too, but I got an expert and let him tell me what I did wrong.
     
  13. Aug 27, 2019 #1353

    pictsidhe

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    LCD-0150 XR-A, rated at 150hp, 565Nm, 20lb

    I'm trying to find out which turbos he used, anyone know?
     
    Last edited: Aug 27, 2019
  14. Aug 27, 2019 #1354

    flyboy2160

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    What? This is the entertainment gift that just keeps on giving! Just use the one that fits! Sort of like "If you can't be with the one you love, love the one you're with."
     
  15. Aug 27, 2019 #1355

    BJC

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    Has Peter forecasted a first flight date?


    BJC
     
  16. Aug 27, 2019 #1356

    pictsidhe

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    That was my theory on his selection criteria, too.
     
  17. Aug 27, 2019 #1357

    pictsidhe

    pictsidhe

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    I wonder how he is going to extricate himself from this mess.

    He's using Marvel Mystery Oil to add lubricity to the Jet-A. Problem with that idea is, it doesn't...
     
  18. Aug 27, 2019 #1358

    Scheny

    Scheny

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    Some captains prefer to sink with their ship. Hope he is not one of them. But in case he prefers this way out, I hope the camera has 4K
     
  19. Aug 27, 2019 #1359

    TarDevil

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    What really scares me is the possibility he'll get desperate after Elliott refuses to fly it and let one of his YouTube enthusiast with some corporate flight time test fly it. He's had several offers, not sure how serious.
     
  20. Aug 27, 2019 #1360

    pictsidhe

    pictsidhe

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    That or fly it himself is far more likely than Eliot flying it. That is assuming that it stays together long enough to reach TO speed.

    Next episode will probably be the final, final, final housing rebuild to add the breather that he didn't know that it needs...
     

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