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    Re: Raptor Composite Aircraft

    So, still no IO-550?
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    Re: High Temp Resin Recommendations

    We're in the process of evaluating high-TG epoxies for a couple of projects in the works. We've considered this one, but the viscosity of 3k cP is a bit high for my taste. For a laminating resin I...
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    Re: Delta wing airfoil

    After a bit of reading on vortex lift, and on Ed Heinemann and the A4 development, I think you're on the right track. As long as you stay in the neighborhood of the A4's thrust/mass ratio, a RIFPIB...
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    Re: Delta wing airfoil

    This is one of those cases where xfoil would probably tell you everything you need to know. My guess is that you'll see a big separation bubble at the forward edge of the flat section starting at...
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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...
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    Re: Delta wing airfoil

    The RIFPIB principle says that an airfoil doesn't have to be very refined in order to be a lot better than a flat plane. Just leave the bottom flat, give the top some sort of curve, make the whole...
  7. Thread: Bearings

    by BoKu
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    Re: Bearings

    Good find; if that bearing matches it's specs, it certainly does have the extended inner ring you're looking for. The spec sheet says that the trade equivalent is R3ZZ, which may or may not be the...
  8. Thread: Bearings

    by BoKu
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    Re: Bearings

    I buy rather a lot of bearings, and I don't think that's how it works. Near as I can tell, ZZ and 2Z are slightly different designations for bearings shielded on both sides.
    ...
  9. Thread: Bearings

    by BoKu
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    Re: Bearings

    All aluminum alloys have approximately the same Youngs Modulus, so within their elastic range, for a given stress they all stretch the same amount. The difference between 7075-T6 and 6061-T6 is that...
  10. Re: Question (from a noob non-pilot): What's up with all the ...

    Those books all seem good. I have the Thomas, and it is great on the theory, though a little shallow on practical matters of detail and execution.

    You might consider coming to one of our Akaflieg...
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    Re: Raptor Composite Aircraft

    Another actual pro tip: If you don't want to be associated with whackadoodle programs, then don't associate with whackadoodle programs. When you do find yourself in a whackadoodle program, your...
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    Re: Raptor Composite Aircraft

    I'd want to see an authoritative citation for that one. I'm pretty sure that if the mass is about right and the CG is right, it will return valuable data.



    The risk/reward thing is an open...
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    Re: Raptor Composite Aircraft

    To abuse the famous Pride and Prejudice quote, "It is a truth universally acknowledged, that an airframe in possession of little service history, must be in want of a proven powerplant."

    Also, I...
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    Re: Raptor Composite Aircraft

    I think that this is a golden opportunity to slap on an IO-550 or whatever is on the SR22 and prove out the structure and aerodynamics with the same installed power as its nemesis. They'd get into...
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    Re: Raptor Composite Aircraft

    I had to hunt up the website: http://www.raptor-aircraft.com/specs.html

    When I looked, it indeed said that the expected empty weight was 2300 lbs.

    As Ross points out, that specs page is heavily...
  16. Re: Homebuilders interested in a CHEAP soaring project see this !

    Spirit and Falcon wings were uniformly mediocre when brand new, and long-term storage of any type is never kind to their unassembled sandwich skins. They are relatively lightweight fiberglass...
  17. Re: Homebuilders interested in a CHEAP soaring project see this !

    That's a steal for the canopy transparency alone. Some early-model Discus or Ventus owner ought to buy it for the canopy and donate the rest to someone who can use it as a simulator. If I was closer,...
  18. Re: Rudder Pedal Spacing - How Far Apart Should They Be?

    This pretty much covers what I came here to add. The ergonomics of sailplane cockpits is a 3D concern that is to a surprising degree constrained by the 2D nature of knee joints. At issue is that most...
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    Re: Superior buys back all XP-382 and XP-400 engines

    Good catch, Marc. Here's the figure in question.

    78734
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    Re: Holes in Spoiler or Not

    So the as-designed Carbon Dragon doesn't have airbrakes? Hmmm...

    The hard part of making Schempp-Hirth airbrakes work properly is keeping the caps from fluttering or pulling upwards while...
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    Re: Superior buys back all XP-382 and XP-400 engines

    This might not be great customer service, but given the bar set by the likes of Jim Bede and Jan Eggenfelner, it's a heck of a lot better than what we've come to expect in the homebuilt world.
    ...
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    Re: Superior buys back all XP-382 and XP-400 engines

    When they have deep pockets.
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    Re: Holes in Spoiler or Not

    Airbrakes like these have so many quirks and subtleties and gotchas that I would stick with what's in the plans until a need to deviate is demonstrated. Once they work, they work great, but making...
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    Re: Raptor Composite Aircraft

    Thanks for that response, and for the reminder that there are actual people behind the keyboards behind these posts on the Internet. My apologies for the snark.

    Yes, you've worked on some amazing...
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    Re: Raptor Composite Aircraft

    Actual pro tip: When boasting about professionalism, use paragraphs and avoid ending your sentences with exclamation points.
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