Raptor Composite Aircraft

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

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  1. May 15, 2019 #561

    rv6ejguy

    rv6ejguy

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    The latest vid covers a lot on the lower gear door actuation. Sorry to say, but all Peter's ideas look bad here. I don't think any of the present plans will work with the air loads present in flight. Anything he's designed on the plane with regards to linkages and latches seems not to work even after several iterations, despite modeling in CAD. He could learn a lot by looking at existing designs instead of trying to re-design the wheel so to speak from scratch. The elevator geometry still looks "awkward" here:

    raptor34.jpg

    His verbal discussion about the redrive re-design to get oil to the prop sounds complicated. Again, he could save a lot of time by looking at existing PSRU designs which run oil to the prop shaft.
     
    Last edited: May 15, 2019
  2. May 15, 2019 #562

    Voidhawk9

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    Not too late to hang a -540 on the back and wring out the aerodynamics in flight whilst the redrive issues are properly resolved. On the current path there are likely to be big issues that cut testing short and cause a lot of delays.
     
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  3. May 15, 2019 #563

    Andy_RR

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    Never mind an IO-540. Fire up a decent CFD package and sort the aero out that way!
     
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  4. May 15, 2019 #564

    Scheny

    Scheny

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    Of course I made a mistake :cool:. I calculated Kilowatt and not horses...

    So 150hp is totally correct!
     
  5. May 16, 2019 #565

    flyboy2160

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    Dude, where's my Mars lander?
    dude where's my car.jpg
     
  6. May 17, 2019 #566

    Scheny

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    Lessons learned:
    Don't do quick math for your mars lander, while in a moving metro and you only have a small phone by hand :D
     
  7. May 17, 2019 #567

    rv6ejguy

    rv6ejguy

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    Doesn't matter if it's 115 or 150 hp. The point is this power setting is nowhere close to a cruise power setting let alone one for takeoff or climb. Doesn't prove much of anything. Peter should be flogging this engine at full power/ rpm on the ground for many hours if he wants to uncover any weaknesses in the engine, turbo system or PSRU. Only after things pass with no issues should he worry about getting the prop set to a compromise pitch setting for initial flights.

    Since the airplane is mostly together now, seemingly rushing towards flight testing, I'm very concerned that he's never performed any static load testing to validate the structural strength and I've never seen any mention of any eyes on the project from an EAA Tech Counselor during construction and pre-cover. Will a DAR pass this aircraft without those things?
     
  8. May 17, 2019 #568

    BJC

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    Peter: “What’s a DAR?”


    BJC
     
  9. May 17, 2019 #569

    TarDevil

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    (...and my student, working on his math, asks, "Why are you giggling, Mr Phil?)
     
  10. May 17, 2019 #570

    TMann

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    When I got my plane (a homebuilt from a kit) there was no pink copy of the AW in the papers although one had been issued.
    I asked the local FSDO if they could help me get a valid cert and give me a defined practice area to operate in. I was replacing the prop with a Catto.

    The guy was great to work with and very helpful. He came up and helped me with the paperwork but I think he was more interested in seeing the plane.

    I pointed out that the plane had a IVO prop on a Lycoming IO-360 which is a big no-no. IVO won't even sell you the prop for that application.
    Also, no fuel selector/shutoff at all.
    No metal firewall, just some fire resistant paint (Ocean.)
    ..... and various other flaws.

    I asked him how anyone could have ever issued a AW cert for this aircraft given these obvious issues?
    He shrugged and said "It's experimental."

    So yes, a DAR may very well pass an airplane as soon as they have a cleared check.

    As far as static load testing .... not required. With the engineering software around a qualified engineer can validate the load capacity of nearly any structure. I'll bet Burt Rutan did it with a slide rule (like they did on the SR-71.)
     
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  11. May 17, 2019 #571

    rv6ejguy

    rv6ejguy

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    Not required but since he plans to build hundreds of these for customers, maybe not a bad idea? Airbus had some wings that passed FEA but failed static load tests on the rig if I recall and just a wild guess- they had better tools to do the FEA and dozens of structural engineers with eyes on that project. Composite structures are harder to model accurately because you never really know what the bond strength is at the joints.

    Peter isn't a qualified structural engineer. He mentions "Mark" oversees some of the structural considerations but doesn't elaborate much there.
     
  12. May 17, 2019 #572

    Marc Zeitlin

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    So in the USA, where we're free to kill ourselves if we are stupid, and as TMann pointed out and we've discussed in other threads a bunch of times, DAR's will pass things that look like they were built by cargo cult devotees out of driftwood and old tire scraps, with beanie cap props as propulsion.

    So something that LOOKS as decent as the Raptor does will have no problem getting an AC in the Exp. R&D category. I argue vociferously that the DAR should be doing the equivalent of a CI, and that the Order that explains to DAR's what they should be doing allows for them to reject aircraft that were built with paperclips and rubber bands, but apparently that's not the training they get when they go to DAR school, and my interpretation of the order is not the one that the FAA has. So, yeah - he'll get an AC easily.

    EAA Tech inspections (no pre-cover inspection is required by anyone) are certainly useful and helpful to amateur builders, but I'd argue that Jeff and Mark (Bettosini, I believe) can more than fulfill that particular role, and have to the extent possible.

    With respect to structural static tests, sure - it would be great to do them as proof. Burt R. designed his aircraft with ridiculous safety factors, so never did structural tests BEFORE the fact (and NONE of his EAB aircraft have ever failed structurally when built anywhere close to what the plans said to do). Some structural tests have been done (I did one on a Varieze a few years ago) and in almost all cases, met the ultimate load requirements. Now, without knowing what load factors or SF's Peter has used in the design of THIS plane, or what structural analysis by either Peter or Mark have been done, yeah - _I'D_ want to either see a structural test to ultimate load on all structures, or I wouldn't get in the plane without it having been tested to limit load + 10% in flight. But this would hardly be the first plane to never have had any structural testing done prior to signoff, first flight, or selling a zillion (or maybe 3) kits.

    My $0.02.
     
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  13. May 17, 2019 #573

    TMann

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    I'll be anxious to see them break one hundred. I believe that Berkut sold 60 kits but not all of those flew.
    Has Icon delivered one hundred yet?

    Let's not get ahead of ourselves.
     
  14. May 17, 2019 #574

    rv6ejguy

    rv6ejguy

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    That's Peter's plan given the many hundreds of deposits he has now. With the aircraft way, way overweight and likely to have much higher fuel burn, much lower speeds, much less range and much higher costs than he predicted, I expect hundreds will bail even if it flies well. That part is also in doubt.

    I'd expect many more problems to solve once it starts flying and many, many more to solve to put it into mass production at a rate that would fill the present order backlog in less than 7-10 years.
     
  15. May 18, 2019 #575

    Tom Nalevanko

    Tom Nalevanko

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    There is resurrected Berkut test flying out of KCMA currently. Very fast and loud!

    Best,

    Tommy
     
  16. May 18, 2019 #576

    BJC

    BJC

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    A single completed kit, or a resurrected kit production effort?


    BJC
     
  17. May 18, 2019 #577

    BoKu

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    Given that most of the extra mass is probably in the (very complicated) propulsion system, that IO-550 is probably starting to look pretty good right now.
     
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  18. May 18, 2019 #578

    rv6ejguy

    rv6ejguy

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    Latest vid talks about getting a DAR out to look at the plane. They will have to get the wings and canard on first which are still being filled and primed.

    Peter mentions shooting for Osh, which sounds like very wishful thinking. Rushing this project is playing with fire. I hope he steps back from this plan and concentrates on a conservative and safe test program.

    Latest engine runs took the engine up to around 190hp (160 short of his takeoff power target) and things were getting hot. Even with passing fuel through the intercooler (bad idea), the IOTs were high. Oil and coolant were way hot (over 250F) but Peter thinks that is the same as his Audi runs in traffic. Nope, never gets that hot and you have probably already compromised the rings a bit by running it there. He has no concept of the intercooler heat loads he'll encounter running 70+ inches at 25,000 feet. Diesel starts boiling at 140-150F and even less up high. The CDT will be exceeding 450F at altitude and it won't be long before the diesel fuel being circulated through the intercooler starts to boil. IOTs and EGTs will skyrocket and this engine will become unglued if it hasn't before then.

    He's no longer running coolant through the fuel tanks now, having disabled that system.

    This project seriously needs an engine guy on board to oversee this rather important aspect.
     
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  19. May 18, 2019 #579

    Hot Wings

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    And more deposits when people get to set in that comfortable 62 inch wide cabin surrounded by all that high tech carbon backed up with a few big screen monitors playing their pretty pictures, even if they have to truck it in.
    /cynical mode

    Now that HBA is again being searched by Google maybe this thread will help those thinking about a deposit make a decision with a little bit more realistic information?
     
  20. May 18, 2019 #580

    Tom Nalevanko

    Tom Nalevanko

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    Re the Berkut, a single aircraft. The pilot told me he found it in a barn 10 years ago... All I know.
    Best,
    Tommy
     
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