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Thread: Raptor Composite Aircraft

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    Moderator Topaz's Avatar
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    Re: Raptor Composite Aircraft

    I don't think anyone here is particularly bashing Peter or anyone else as a person. The most-apt (and American as apple-pie) phrase that comes to mind about this project is, "Bit off more than he can chew."

    Nothing wrong with trying to do better than anyone else has done. Nothing at all. But airplane design is challenging enough even for "stupid simple" designs that it's probably a better idea to start with one of those, or maybe even two, before you go getting other people to commit money to something that even highly-experienced professionals would find to be a challenging requirement set. As has been said by others in this thread, even presupposing that this is going to be a development program and that the prototype might not fully live up to the goals, it might not have been the wisest course to make said prototype of "final product" fit, finish, or quality. Build it rough and easily-changed first (and less expensive in terms of time and cost), and then make a "pretty one" after you've proved the concept is sound and the benefits real. Your investors would probably appreciate this approach as well.

    If there's any personal failing here at all, from what little I know of the project, it's hubris. No more, no less.
    "If you have built castles in the air, your work need not be lost; that is where they should be. Now put the foundations under them." - Henry David Thoreau

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    Re: Raptor Composite Aircraft

    Quote Originally Posted by Topaz View Post
    I don't think anyone here is particularly bashing Peter or anyone else as a person. The most-apt (American as apple-pie) phrase that comes to mind about this project is, "Bit off more than he can chew."

    Nothing wrong with trying to do better than anyone else has done. Nothing at all. But airplane design is challenging enough even for "stupid simple" designs that it's probably a better idea to start with one of those, or maybe even two, before you go getting other people to commit money to something that even highly-experienced professionals would find to be a challenging requirement.

    If there's any personal failing here, from what little I know of the project, it's hubris. No more, no less.
    Not knowing what one does not know is a disastrous flaw in a design engineer or a want-to-be design engineer. Especially if the effort involves other people’s money and / or puts other people’s lives at risk.


    BJC

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    Re: Raptor Composite Aircraft

    When I look at the comments on their YouTube vids, I see comments along the lines of "conventional airplane engines are such dinosaurs..." I think that a lot of this thinking comes from observing that the horsepower per cubic inch of direct-drive air-cooled engines is fairly modest, and that power per in^3 of modern car engines is much greater. The thinking seems to be that power / displacement is some sort of metric of effectiveness at which common airplane engines are deficient.

    In truth, power / displacement is a relatively meaningless number; it doesn't tell you much of value. Power / mass, sure, that's useful, as is power / fuel/hour (BSFC) and even power / installed volume (cowlings can only be so big). But by fetishizing a relatively meaningless metric, a lot of people are missing the point about how effective conventional powerplants really are.

    Conventional airplane engines have a lot of displacement per unit power because that has evolved as the most effective way of delivering power at prop-friendly RPMs. With a lot of cubes, you get a lot of torque, so you can deliver that power directly into the prop without needing an expensive, complicated gearbox with its inevitable mass and reliability baggage.

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    Re: Raptor Composite Aircraft

    Peter had said in one video that if it doesn't work as planned people will then be able to say "I told you so" but to give him the chance to finish, fly and prove it. Fair enough. We'll have to wait for the flight testing to see but there are so many "gotchas" here, I do hope they play everything safe and evaluate the risks fully before flying. Better to admit defeat, disappoint the investors and onlookers if it's not safe than to get someone hurt.
    Ross Farnham
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    Re: Raptor Composite Aircraft

    Quote Originally Posted by ScaleBirdsScott View Post
    ... it seems that the only important goal is to make a thing that manages to obtain the property of flies=yes.
    I respectfully disagree. If just "flying" were the goal, the airplane wouldn't have an interior, an air conditioner, a full IFR stack, etc. It would be a bare-bones prototype that shows that the aerodynamic analysis was accurate and that the performance met the predictions. It would have then also given an indication of structural capabilities and weights, and an idea as to whether this engine choice actually has any viability.

    Quote Originally Posted by ScaleBirdsScott View Post
    Because accomplishing that is at least a validation of some kind to investors/followers/etc that this project has realized some kind of goal and that, even if the result (as so often is the case today) is in fact mostly only fit for a Doggo Meal, it has served as a proof and catalyst for further development.
    Sure - at this point, in desperation (and this is EXACTLY what happened with Cobalt and the Valkyrie), the airplane HAS to fly to show the investors that SOMETHING is working and to keep the $$$ flowing. So the pressure is on to do dangerous things (which is exactly what Cobalt did), or else the project stops. If the investors are smart, they'll understand the "Sunk Cost Fallacy", but I cannot tell you how many $$ people and managers I've worked with that don't understand it...

    Quote Originally Posted by ScaleBirdsScott View Post
    I guess is, Dunning–Kruger + resources + hard work + good persuasion skills gets a lot of things done in this world. One option is it could yield a second, better attempt down the road.
    DK NEVER leads to good results or gets things done - it only ever stands in the way. Hard work is necessary but not sufficient. Good persuasion skills gets investors, but does not produce product. What produces product is good ideas, quality execution, and hard work.

    At any rate, I really don't give a crap about the investors - if they don't understand what they're investing in, that's their problem, and it's only $$$. What I DO care about is safety and people getting hurt or killed. And given what numerous folks have said about structural, aerodynamic and propulsion issues with this plane's design, I have major concerns about anyone who puts their butt in the left seat. I have been convinced that the torsional loads on the wing ARE meant to be taken by the small hole and pin in the strake/wing leading edge that was pointed out. But that's only one of MANY concerns that have been voiced.

    And as an aside, I've worked on teams (some of them absurdly poorly run) that have built flying aircraft in 6 months, from a clean sheet. Scaled regularly used to build planes from a clean sheet in a year or less, with a couple of engineers and a small team (3 - 5) of fabricators. But of course, Scaled knows what it's doing (at least using the old, obsolete and tired methodologies that need to be retired, per the current crop of "innovators" I've mentioned previously).

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  9. #501
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    Re: Raptor Composite Aircraft

    Quote Originally Posted by ScaleBirdsScott View Post
    If I put myself in this Peter guy's shoes, it seems that the only important goal is to make a thing that manages to obtain the property of flies=yes.
    If Peter pushes it outside and smears cow dung all over it, this metric should be within reach without endangering too many lives and while keeping costs to a minimum...

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    Re: Raptor Composite Aircraft

    Quote Originally Posted by Topaz View Post
    This documentary of a business meeting, almost identical to some I've actually attended, demonstrates it well.
    hat was the one of my points long time ago. But believe it or not we (software guys) have a solution for this program


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    Re: Raptor Composite Aircraft

    Quote Originally Posted by rv6ejguy View Post
    Peter had said in one video that if it doesn't work as planned people will then be able to say "I told you so" but to give him the chance to finish, fly and prove it. Fair enough. We'll have to wait for the flight testing to see but there are so many "gotchas" here, I do hope they play everything safe and evaluate the risks fully before flying. Better to admit defeat, disappoint the investors and onlookers if it's not safe than to get someone hurt.
    Amen to that observation.

    Given the lack of adequate testing of the engine/redrive combo, I have voiced a concern for the safety of the test pilot over and over again and recommended acquiring a used Lyc. 540 or Connie 550 and installing it to investigate and prove the aero design first . A suggestion not received well. Did you fall off the face of the earth again

    The engine/drive package due to its overcomplexity brings with it an insane number of potential failure modes that in my opinion far outweigh the advantages,if any, that it may or may not provide.

    I try very hard to strongly emphasize the importance of cautious,calculated,and responsible judgement needed in the test phase of an aircraft development program. Whether or not that advice is followed is out of my control.

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    Re: Raptor Composite Aircraft

    Quote Originally Posted by canardlover View Post
    Amen to that observation.

    Given the lack of adequate testing of the engine/redrive combo, I have voiced a concern for the safety of the test pilot over and over again and recommended acquiring a used Lyc. 540 or Connie 550 and installing it to investigate and prove the aero design first . A suggestion not received well. Did you fall off the face of the earth again

    The engine/drive package due to its overcomplexity brings with it an insane number of potential failure modes that in my opinion far outweigh the advantages,if any, that it may or may not provide.

    I try very hard to strongly emphasize the importance of cautious,calculated,and responsible judgement needed in the test phase of an aircraft development program. Whether or not that advice is followed is out of my control.
    Jeff, I’m fairly confident that your advice to Peter would have unanimous backing from forum members. Over the last week or so since the last run of the engine where there was another minor leak from the gearbox, I have been strongly tempted to contact Peter with exactly the same advice that you have offered him, for exactly the same reasons. An engine failure at 200’ on the first flight would likely see an end to the program.

    At the end of the day, it’s the airframe and it’s performance that Peter needs to demonstrate and validate. The customers are not so concerned about the Audi engine, which is supported by the fact that we are having so many enquiries about our turbine engines from Raptor buyers, and many of our own delivery slot holders are Raptor buyers.

    From a purely selfish commercial perspective, I want to see this program be successful as I will then have 1500 potential customers for our future 300hp Turboprop. However, I am an enthusiast above all and Peter’s concept clearly has appeal which is demonstrated by his order book. I sincerely hope that regardless of what engine goes into the Raptor that the hopes and dreams of those that want a Raptor are not dashed when the prototype rolls itself up into a ball following an engine failure, and the program grinds to a halt.
    Turbine Aeronautics

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    Re: Raptor Composite Aircraft

    Quote Originally Posted by Topaz View Post
    I don't think anyone here is particularly bashing Peter or anyone else as a person...
    You should restrict this sentiment to yourself. What do you mean? "Well, he's an arrogant, incompetent huckster who suckered money in with B.S. promises, but he's an OK person because he likes puppies and gives to charity? This level of arrogant incompetence IS a proper cause to judge him as a person.

    Quote Originally Posted by BJC View Post
    Not knowing what one does not know is a disastrous flaw in a design engineer or a want-to-be design engineer. Especially if the effort involves other people’s money and / or puts other people’s lives at risk.
    BJC
    Quote Originally Posted by Marc Zeitlin View Post
    ...So the pressure is on to do dangerous things ...What I DO care about is safety and people getting hurt or killed. ..... I have major concerns about anyone who puts their butt in the left seat......
    I'm not as concerned about a test pilot getting killed. If he's not enough of an engineer to sniff out the B.S. here, well he'll be a candidate for a Darwin award. Even though they'll have to fly at first far away from Disneyland, a bigger concern is people underneath this thing who never signed up to be endangered by this mess.

    This isn't 1904. Spare me the 'they will learn from this' positive spin. There is plenty of engineering knowledge available to have avoided this flying hype-mobile.

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    Re: Raptor Composite Aircraft

    Quote Originally Posted by canardlover View Post
    Amen to that observation.

    Given the lack of adequate testing of the engine/redrive combo, I have voiced a concern for the safety of the test pilot over and over again and recommended acquiring a used Lyc. 540 or Connie 550 and installing it to investigate and prove the aero design first . A suggestion not received well. Did you fall off the face of the earth again

    The engine/drive package due to its overcomplexity brings with it an insane number of potential failure modes that in my opinion far outweigh the advantages,if any, that it may or may not provide.

    I try very hard to strongly emphasize the importance of cautious,calculated,and responsible judgement needed in the test phase of an aircraft development program. Whether or not that advice is followed is out of my control.
    That has to be frustrating to work there under this sort relationship. At least you've said your piece here and many appreciate the clarity you've brought to this thread.
    Ross Farnham
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    "The world is changed by your example, not by your opinion" Paulo Coelho
    http://www.sdsefi.com/aircraft.html




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    Re: Raptor Composite Aircraft

    Quote Originally Posted by flyboy2160 View Post
    You should restrict this sentiment to yourself. What do you mean? "Well, he's an arrogant, incompetent huckster who suckered money in with B.S. promises, but he's an OK person because he likes puppies and gives to charity? This level of arrogant incompetence IS a proper cause to judge him as a person....
    Accusations of malfeasance, fraud, or just plain ill-intent are best left to the appropriate legal venue, not this forum. If you don't have standing to bring such an accusation in court, you don't have any kind of moral standing to bring the same here. HBA's founder recognized this from the beginning, which is why this is included in the HBA Code of Conduct, specifically paragraphs 9 & 10. Probably something you'll want to read at a time of your convenience during the next minute or two.

    While there are certainly a lot of aspects to the Raptor project that are appropriately described as "questionable", what you're doing is attacking the person involved. You're welcome to do that on Facebook, on rec.aviation.homebuilt, or over a beer in your favorite establishment, but don't do it here. There's plenty of material in this project for technical discussion of the potential pitfalls and problems with the airplane and engine without resorting to attacks on the people involved, and the other members posting in this thread have managed to do so for over 500 posts. Theirs is an excellent example for you to follow.

    If you disagree, or want to discuss this off-topic issue further, I invite you to PM myself or any of the other moderators of this forum. Have a great day.
    "If you have built castles in the air, your work need not be lost; that is where they should be. Now put the foundations under them." - Henry David Thoreau

    Design Project: Conceptual Design of an "Inexpensive" Single-Seat Motorglider
    Discussion Thread for the Project: Discussion: Conceptual Design of an "Inexpensive" Single-Seat Motorglider

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    Re: Raptor Composite Aircraft

    Quote Originally Posted by Topaz View Post
    rec.aviation.homebuilt
    You're really dating yourself there
    I reserve the right to be smarter tomorrow than I was yesterday.

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    Re: Raptor Composite Aircraft

    In the latest video, it was good to see Peter replace all the welded aluminum bellcranks with 4130 ones. Maybe someone looked at my comments...

    Looks like they have 14.5 degrees of elevator up travel now so that seems better than the first design. Have to see what the control forces are like though with the linkage design.

    The intake scoop design gets heavier and more complicated all the time and it's completely unneeded. Controlling the outlet flow is easier, lighter and more efficient from a drag point of view. Lots of time wasted on this unfortunately. Should just use a fixed inlet.

    The strake fairing on the door looks like a bad idea but there is no other choice at this point. I think the door will change shape with pressurization loads and this will misalign the strake fairing with the rest of the wing, probably tripping the airflow. Don't see how this can be made to fit well in flight and still have the door open properly on the ground.

    Redrive bearing wear doesn't look good after a short time running. That will involve more time to fix again.
    Ross Farnham
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    "The world is changed by your example, not by your opinion" Paulo Coelho
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    Re: Raptor Composite Aircraft

    So, still no IO-550?
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