Raptor Composite Aircraft

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

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  1. Sep 16, 2019 #1661

    pictsidhe

    pictsidhe

    pictsidhe

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    We can only speculate why he has only run it at full power for less than a minute at a time. No sane person would try a first flight with that amount of testing on any engine, let alone an experimental one that so many are highly dubious about.
     
    Last edited: Sep 16, 2019
  2. Sep 16, 2019 #1662

    Voidhawk9

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    Yes. I needs to be runs for HOURS at max continuous, if not full power. If his claims about the setup are valid, running full power should be no issue.
    Hook up some blowers to the cooling inlets to permit the long runs while tied down. He can then blame the blowers for the inadequate cooling.
     
  3. Sep 16, 2019 #1663

    BJC

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    I’m with Topaz; it is fair game to comment on technical and business model concerns, or to express concerns for safety, but betting on a catastrophic ending should not be something done here on HBA.


    BJC
     
  4. Sep 16, 2019 #1664

    TFF

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    Good or bad design, if he gets stuck having to make the first flight, hopefully self preservation kicks in and he learns how to fly a canard well before attempting. I am no canard flyer but I have seen low time canard pilots PIO or fly way too fast on approach and generally look out of control. Most are not going to stick and rudder one.
     
  5. Sep 16, 2019 #1665

    rv6ejguy

    rv6ejguy

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    He's had several YT pilots offer to fly it for him.
     
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  6. Sep 16, 2019 #1666

    Turd Ferguson

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    Walter Mitty lives on YouTube.
     
  7. Sep 16, 2019 #1667

    AdrianS

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    Fit it with remote control for the taxi tests.
    Let the youtubers bid for the right to "fly" it.
    Win-win, and nobody dies.
     
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  8. Sep 16, 2019 #1668

    Turd Ferguson

    Turd Ferguson

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    If he taxi's around enough he will convince himself he can lift the nosewheel. If he lifts the nosewheel enough, he will convince himself he can fly in ground effect. If he flies in ground effect he will convince himself he can fly around the pattern. If he flies around the pattern..........
     
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  9. Sep 16, 2019 #1669

    Bert

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    Pardon my ignorance but I don't understand this comment. To the best of my [rather limited] knowledge, there is no foam used in the construction of the Raptor itself, only in creating the molds.
     
  10. Sep 16, 2019 #1670

    pictsidhe

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    I could be wrong. But in a strake layup video, there appeared to he a layer of divinycell on top of the 1st layup out of the bag. Even without foam, that seems like a lot of heat to try dissipating through the floor of the tank. That assumes decent agitation so the hot fuel doesn't just sit on top...
     
  11. Sep 16, 2019 #1671

    Topaz

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    This is my concern as well. Especially that last "leap." Once it's hopped, I've been aware of more than one builder, who intended to do a "go slow" flight-test program, give in to their adrenaline rush and excitement over a crow-hop and immediately make a "once around the patch" first true flight. I've read of a couple who just got into the pattern and flew off to their practice area, leaving those on the ground for a simple "first flight" wondering what the heck is going on.

    Given the penchant for "build first, figure out the problems later" that seems to be prevalent in this project, I'm very concerned that, if he gets it in the air himself at all, into ground effect as he's suggesting he might, he's going to ride the adrenaline rush and "go ahead" and try to make the first full flight himself, too, on the basis of, "everything went fine on the ground-effect hop." Assuming it does "go fine", of course, which may be a big assumption.
     
  12. Sep 16, 2019 #1672

    Jeff Liot

    Jeff Liot

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    First post on this forum and possibly the last.
    I like to think that the homebuilt community exists to help and support each other.
    The attention being given here to Peter's project is nothing short of a witch hunt.
    Some of you guys are just stoking your own egos at the expense of a fellow builder who is simply trying his best but may not be meeting your high standards. Criticizing is easy. If you really care, go visit Peter at his project location and help out as best you can.
    Jeff
     
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  13. Sep 16, 2019 #1673

    TarDevil

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    Read the entire thread, Jeff.

    It isn't my nature to directly criticize, but people who pop in, read a few post then flame a knowledgeable group of aircraft builders and designers is classic trolling and blatantly immature.

    Many here have offered Peter help... Peter dismissed their good will.

    Educate yourself first, Mr. Liot
     
  14. Sep 16, 2019 #1674

    Turd Ferguson

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    Peter should be following the highest - or setting an even higher standard. He is planning on selling his product to the general public that doesn't know any better.
     
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  15. Sep 16, 2019 #1675

    Scheny

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    Jeff, I agree with you and Topaz that calling names does not help. Peter has put himself in the situation that he is both in the spotlight of YouTube and in addition the "CEO" of his aircraft startup.

    I am thankful to him to have the opportunity to watch this build twice per week and I am also a fan of the design itself. Yet, there is the other side, where ailerons and nosegear do what they want, the transmission is after n iterations still free floating etc.

    Other topic. All turbo diesel use the diesel as a lubricant and the excess pressure of the common rail is dumped back to the tank. From this alone, no big heat added here. Using it for the intercooler does. Still, 35kW seems odd to me. Fluid transfers much heat, but you got the air on the other side. Heat transfer is not linear with the speed of air flow, so I cannot image it is even possible to get near 35kW.
     
    Last edited: Sep 16, 2019
  16. Sep 16, 2019 #1676

    Rik-

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    I'm new here but there's a lot of NEGATIVE outlooks on a guy that's willing to put it all on the line for everyone to see.

    In the turbine world, the fuel is used as an oil cooler. Also, they preheat the fuel in the turbine applications too so I don't see what the worry is about the heat of the fuel.

    In all honesty, the structure is more of a problem to heat than the fuel so it might be more productive to calculate the heat retention of the structure rather than speculate the radiant heat to the fuel tanks.

    Didn't he have the plane signed off already by a DAR?
     
  17. Sep 16, 2019 #1677

    Malish

    Malish

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    I did ask Peter to visit him and his shop a few ears ago - he did refuse me.
     
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  18. Sep 16, 2019 #1678

    Topaz

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    First off, welcome to HBA! :)

    Secondly, and in answer to your comment, Peter's project is making some extraordinary claims for performance, utility, and efficiency, which do demand extraordinary evidence that the engineering and execution of the project are living up to those claims. We have quite a lot of people here on this forum that constitute an extraordinary breadth and depth of knowledge about aircraft - and especially homebuilt-style aircraft. Some of those people have logged well-reasoned and very legitimate concerns about some things they're seeing on the YouTube videos documenting this project. Some have tried to contact Peter about their concerns, via YouTube comments and, I believe, by more direct means as well. To the best of my knowledge, their concerns and constructive criticisms have all been rebuffed. Given that this is Peter's first "full scale" airplane design, and the level of performance and complexity that he's attempting on that first design, I'll understate and say that I don't think ignoring the proffered constructive criticism and advice he's being given, out-of-hand, is really a wise course of action.

    By the same token, yes, Peter is at least "trying", and he's trying fully out in public for all the world to see his success, failure, or anything in-between. I do applaud him for that. And, yes, this is "the Internet", so there most-certainly is some "dog-piling" going on in this thread, where it turns into a bit of a feeding frenzy (too many metaphors, Topaz! :confused:) where people repeatedly chime in with far-less-warranted criticisms, personal attacks on Peter and, recently, humorously-intended "wagers" on how badly this will turn out and how badly he'll be hurt.

    When we get to that point, it's going too far. There are definitely engineering and production concerns with this project, and discussing them is a healthy and educational thing, especially here on HBA. When it starts getting personal and even ugly, that latter stuff needs to stop. As a moderator here, I'm asking everyone to please tone-down that aspect of the discussion.

    Unfortunately, the reality is that this means little more than his paperwork was in order. A DAR (or even a full-blown FSDO examiner, if they still did that) isn't going to do much more than check your paperwork and give a cursory once-over to the airplane, to make sure you haven't done anything obviously stupid that could get the FAA in public-relations trouble if they give you an airworthiness certificate and the airplane falls on someone's head. An airworthiness certificate pretty much means that you've dotted your "i"'s and crossed your "t"'s, not that your experimental airplane is safe for you to fly.
     
    Last edited: Sep 16, 2019
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  19. Sep 16, 2019 #1679

    bmcj

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    NOTE: I was typing this at the same time as Topaz was posting his comment just above, so yeah, what Topaz said!

    To Rik and Jeff Liot, I have to ask a question of both of you. With two new (or in Jeff’s case, relatively new) members jumping to Peter’s defense at roughly the same time, are you both here as part of a coordinated campaign? In other words, are you both responding to a request or suggestion that people join HBA and comment in support of the Raptor? I’m not saying that’s a bad thing, but the timing seem like it might not be coincidental.

    I also noted that Rik just joined and his profile shows a birthday of 1-1-01. While that is entirely possible (making Rik only 18), I think it more likely that the date was a quick entry to get through the registration process. I have to admit that given all this, it crossed my mind that Rik might actually be Jeff with a second profile.

    Anyway, my second paragraph is neither here nor there, but my first paragraph is a valid question that I hope you will answer. As far as our discussions go, they occasionally take on a less than desirable ton, but our moderators are quick to call people out on them (just as Topaz did a few posts ago) when posts are deemed as less than appropriate. Overall, though, most of the posts in this thread, both positive and negative, are logical and well thought out, and made out of concern for Peter. I agree with TarDevil that there are many posters here that are trying to help and have even offered their suggestions to Peter beyond the scope of HBA.
     
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  20. Sep 16, 2019 #1680

    Topaz

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    Looking at their registration information in more depth (I get to see more of that), they're probably not the same people.
     
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