Another Canard Dream...

Discussion in 'Hangar Flying' started by Apollo, Nov 15, 2013.

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  1. Nov 15, 2013 #1

    Apollo

    Apollo

    Apollo

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    A friend sent me this link to review: composite kit aircraft, Raptor Aircraft Pricing

    This is an interesting and ambitious project with aesthetically pleasing elements. The website has some beautiful CAD graphics, but includes more than one incorrect statement about canard aircraft. It's apparent the designer has learned SolidWorks but does not have much engineering or aerodynamics experience. I see design deficiencies they have overlooked.

    Now they want to take deposits before building and testing a prototype, which is a huge red flag. That business model (for developing experimental aircraft) has failed over and over again. They also have an Indiegogo effort to raise $400,000 to build the prototype.

    The designer mentions his relationship with Jeff Kerlo, who designed the V-Raptor that was discussed in another thread. Wasn't there a controversy about ownership rights for that design? I'm afraid this new effort is going to end badly for depositors.
     
  2. Nov 15, 2013 #2

    autoreply

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    Outside the obvious issues; some random remarks:
    *How can you possibly pressurize such windows? Has that ever been done succesfully?
    *Same for the cabin? Any planes with a significant non-round cross-section, apart from double bubbles/flat bottomed airliners with a pressure-load-carrying floor?
    *Wasn't a PT6 alone 250K?
     
  3. Nov 15, 2013 #3

    Topaz

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    Enough said for me right here, regardless of the technical merits (or demerits) of the design. I don't have any issue with someone putting up a crowd-funding effort to seed-fund their concept -that's what crowd-funding is for. When you donate money to one of those efforts, you're an investor, and that means you may get exactly nothing for your money.

    But a legitimate company doesn't take deposits until they have a tested, saleable product. Especially on something as complex and prone to delays and revisions as an aircraft design. A complex, turbine-powered aircraft design even more so. This site has all the hallmarks - lots of pretty computer-generated pictures, lots of lofty claims that have not been demonstrated, let alone proven. And they're asking for simply huge deposits, up front, years before they could possibly fulfill your order.

    Let's all say Dreamwings together, shall we?
     
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  4. Nov 16, 2013 #4

    Aviator168

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    Why. The only difference I can see from the Velocity is pressurization.
     
  5. Nov 16, 2013 #5

    Toobuilder

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    The "technical details" presented on the site appear to be aimed at a junior high audience. It takes about 5 seconds to see this project is going nowhere at best, and an outright scam at worst. I can't believe anyone would send these people money. Makes the Moller effort appear legit by comparison.
     
  6. Nov 16, 2013 #6

    Topaz

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    We need to be careful about words like "scam". I wouldn't send these people my money for the reasons I outlined above, but I want to clarify that by "legitimate", I really meant "viable", "well-planned", or "qualified to run a business". I can see how I phrased that poorly, and it would be very easy to misunderstand. As outlined in the HBA Rules of Conduct, we should let any accusations of criminal activity be made in a court of law by parties involved.

    No offense to you personally, Toolbuilder, it's just that Jake would prefer it this way on HBA.
     
  7. Nov 16, 2013 #7

    Kyle Boatright

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    I like the part about the design being area ruled. Obviously, what the world needs is a transonic canard pusher.
     
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  8. Nov 16, 2013 #8

    bmcj

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    Speaking of... I recently read that Moller is planning on launching a crowdfunding effort. But I digress from the original subject: any further discussion of Moller belongs in its own thread.
     
    Last edited: Nov 16, 2013
  9. Nov 16, 2013 #9

    Apollo

    Apollo

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    I'm also okay with crowdfunding such efforts. The whole crowdfunding concept is to reduce the risk for any one "investor" to manageable levels. You don't contribute more than you're willing to lose. It's a gamble and most donators understand that (or should).

    I'm not sure what to think about someone that would make a $20,000 deposit based on this website. The completed aircraft is projected to cost over $250k. Where is the buyer's due diligence for such an investment? Clearly the depositors have more money than common sense. People and their money should be protected from predators, but how much obligation do we have to protect the foolish from even bigger fools?

    I also don't believe this project is a scam - they truly want to build it. But that doesn't mean they have the engineering depth, the business knowledge, the ethics, or the technical resources to be successful. In my opinion, the evidence indicates they do not.
     
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  10. Nov 16, 2013 #10

    Topaz

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    In my personal opinion, I agree, especially since you have experience with this configuration that I absolutely do not. In terms of my last post, I have a duty to Jake to enforce the rules of HBA. I know you're not talking about that.

    I suppose, in the end, all we can do is exhort people interested in this product to be cautious. That there are concerns. After that, it's up to them. They're nominally adults, and responsible for their own actions.
     
  11. Nov 16, 2013 #11

    Toobuilder

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    I hope my post on the subject does not appear accusatory, but let's be honest, alarm bells and big red flashing lights should be going off in anyone's head reading the info on that site.

    OTOH, perhaps I'm too jaded, and should have called the guy back who wanted my Hiperbipe a few months ago...

    ...the guy who said he was the nephew of the Syrian defense minister and needed a way to invest in American General Aviation...
     
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  12. Nov 16, 2013 #12

    Topaz

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    What possibly could've gone wrong? :gig:
     
  13. Nov 16, 2013 #13

    Himat

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    If the windows where anchored at the edges in a way that did take tension forces it might be possible.
    I have never heard about anyone that have done this successfully nor tried without success.


    A pressure vessel doesn’t have to be round, other format works to. Usually with a more or less sever weight penalty. In subsea equipment you do find these non round pressure vessels. But there the weight is often not critical.
     
  14. Nov 16, 2013 #14

    Hot Wings

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    Just posting here on HBA is probably good enough. HBA has a high enough ranking on the search engines that if it has been mentioned here it's generally on the first page of a search. If potential customers aren't diligent enough to at least do a simple web search for information then they likely wouldn't be swayed by our opinions.
     
  15. Nov 17, 2013 #15

    autoreply

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    In pure bending I meant. Putting such large flat panels under pressure requires ridiculously thick windows.
    And they're thick-walled right? Even an airliner has only a millimeter of outer skin. Without internal pre-stress in pure tension (like a floor or double-bubble) you can't have non-round/double curved surfaces. The bending forces are simply a few orders of magnitude too large.
     
  16. Nov 17, 2013 #16

    Matt G.

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    That's about the minimum you would see, in only a few areas. That's roughly the minimum skin gage of a 737, but most of it is at least 2 if not 3 times thicker than that. Larger aircraft, even more so.
     
  17. Nov 17, 2013 #17

    autoreply

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    To the best of my knowledge, the smaller (composite) new jets are just over a millimeter. Just measured the A380's skin thickness (GLARE) and it's 3.6 mm. Even a 1ft thick beam would be humongous to cope with the pressure-induced bending.
     
  18. Nov 18, 2013 #18

    Aircar

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    Pressure vessels don't need to be COMPOUND curved --a pure cylinder or any part cut from one , will do just fine --the flat wrap windscreen for example or any airliner passenger window, or the Lear Jet screens for another quick one (provided the detail design of load take out is OK) . Maybe that wasn't the issue referred to but just thought it might have been.

    It appears to be yet another "EZE" rip off with minimal and insignificant alteration (the over wing intake is similar to a roadable canard (Haynes Skyblazer) being pushed and also looking for untutored investors --the prices,etc and use of a PT6 don't seem to add up even closely.

    I DO take issue with the 'kickstarter' and other 'crowdfunder' financing models because the other side of the 'open slather' money chase was MEANT to include crowd questioning --the 'due diligence' being spread over many minds as well as the come-on for greenbacks . This side of the equation has been missing on many many kickstarter type start ups (and shut downs) even though it started with the best of intentions . The inevitable 'kickback' from these schemes is appearing and will taint the whole emerging new technology field like nothing else since the Wall street free for all .
     
  19. Nov 18, 2013 #19

    BoKu

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    Ross, what rings my alarms about this project is that it looks like just one more of those "black aluminum" airplanes where they treat composites like they would aluminum, and pass up opportunities to take advantage of all the neat things that you can do with composites. I see this in the multitude of discrete stiffeners, and what appears to be a lack of sandwich construction.
     
  20. Dec 13, 2013 #20

    Aircar

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    Bob, I missed your post till just now --you may well be right , the LearFan was basically a standard rib and skin ,stringers etc construction in carbon but a good friend of mine and well recognized expert in composites (John Hart Smith) was 'seconded' /loaned to this project for advice on the structural design --to Bill Lear from Donald Douglas Jnr -- and I would defer without hesitation to his expertise in the minimizing of structural weight in this sort of thing. The 787 flaps are built over here and I was working on the F 18 fatigue program at the time the first set were brought in for structural testing --and witnessed the maximum service load test (after which they conduct the long term fatigue test and THEN actually find the ultimate load and break them ... after my contract ended ) --there were as man or more fasteners in those flaps as any metal one of the same size (we built C130J and other flaps/ailerons and rudders here also --seen them all in build )

    They had discrete ribs and stiffeners exactly as if in aluminium -- no sandwich in any of the Boeing composite parts AFAIK (maybe trim tabs) -- don't know enough to know whether this is optimal or for inspection/access etc or certification redundancy etc . I am told that the 787 that suffered battery melt down fire in the ELT (on the ground in England is STILL grounded and that to repair it they have to build a COMPLETE fuselage barrel section just to get the replacement upper shell section and then have to figure out how to splice it all together and tie in to the co cured stiffeners and frames with pressure integrity and no offsets etc etc --seems that is not yet worked out..... at low loading intensity I think sandwich is optimal but for higher loadings the buckled shell or even tension field frame is better (the rudder was best made as a tension field structure in carbon according to John --the wrinkles might not have inspired passengers though .
     

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