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  1. Marc Zeitlin

    10/23 Raptor Video

    And this thesis, from 1936 (Caltech), says pretty much that, and has some references to other documents that say similar things. https://thesis.library.caltech.edu/577/1/Malina_fj_1936.pdf It is interesting, however, to see that it's very dependent upon the blade angles of the prop. Way too...
  2. Marc Zeitlin

    TONS of low cost King Mode C's out there... opinions?

    That's not how 91.413 tests work. A Transponder check, done every 24 months per 14 CFR Part 91.413, is done IN the plane, including the transponder, altitude encoder, and transponder antenna. It tests the system, including the static port connection to the transponder altitude encoder. So...
  3. Marc Zeitlin

    New Optional Task-based Phase 1 Flight Test Program for E-AB

    Agreed - for very simple planes, fewer than 30 hours may very well be required. And what set me off on the first posting was that the poster only tested two of the corners of the envelope, and not the most important ones, then claimed that he needed fewer hours because he didn't need to test...
  4. Marc Zeitlin

    New Optional Task-based Phase 1 Flight Test Program for E-AB

    I do. And while I CERTAINLY agree that the 3,053'd RV-7 is going to be WAY more similar to the 15th RV-7 is than the 3,053'd Long-EZ is to the 15th Long-EZ, there are still a zillion things that are not identical. Did the builder install the rod ends correctly? Did he tighten all the jam nuts so...
  5. Marc Zeitlin

    New Optional Task-based Phase 1 Flight Test Program for E-AB

    I will disagree that it can possibly take substantially less than 40 hours to TRULY test a new aircraft, kit or otherwise, modification or otherwise. While you may have followed the plans/kit instructions to the letter, and didn't change much, your plane was NOT built in a factory, using factory...
  6. Marc Zeitlin

    10/23 Raptor Video

    I haven't been paying close attention - is PM really discussing some 40 hour limit on flight testing? And flying the plane outside of the 50 mile radius from KVLD? All I can tell you is that a substantial portion of both the original builders (the folks that actually APPLIED FOR and got the...
  7. Marc Zeitlin

    10/23 Raptor Video

    So there's been a bunch of speculation here regarding the Airworthiness Certificate, Operating Limitations, Area Restrictions, and other issues surrounding possible flights to California and other testing. Not being one for speculation, I spent the $10 to get the aircraft records from the FAA...
  8. Marc Zeitlin

    Adjusting Airspeed for Altitude

    Since the LSA requirement states that CAS is used for stall speed limitations, if one doesn't know what one's CAS is in relation to IAS because one has done zero in-flight calibration, then one has no clue whatsoever whether one is legal or not. I've seen systems that are off (in one direction...
  9. Marc Zeitlin

    Adjusting Airspeed for Altitude

    You're conflating two different things. You're absolutely correct that the INSTRUMENTS need to be calibrated, so that when they're fed a specific pressure, they read correctly. However, this is NOT the same as calibrating the SYSTEM as it's installed in the aircraft. One can imagine that if the...
  10. Marc Zeitlin

    Adjusting Airspeed for Altitude

    This is true. With E-AB aircraft, very few do ANY testing, other than flying around in circles at mid weights and mid CG during their ostensible Phase I "test" period. Can you tell this is one of my hot buttons? Why would the FAA specify how to calibrate airspeed indicators in the FAR's? Not...
  11. Marc Zeitlin

    Adjusting Airspeed for Altitude

    So the short answer is "NO". Firstly, the stall speed isn't defined at SL - just the maximum speed is. Secondly, LSA rules require a 45 KCAS stall speed at MGW and full forward CG. Altitude means nothing - CAS is CAS. If you've calibrated your airspeed with respect to your IAS, then you know...
  12. Marc Zeitlin

    10/23 Raptor Video

    I wish it were that simple - while there's a lot of extraneous systems weight and weird reinforcements that could be removed and obviously a lot of weight removed by switching to a Lycoming or Continental engine (which would then allow removal of nose ballast), dropping it down to the ~2100 -...
  13. Marc Zeitlin

    10/23 Raptor Video

    Nope. Not at 1100 lb. overweight, it isn't, for just one example. The record is full of myriad other issues as well. Closer in the sense that Mars is closer to Pluto than Earth is, maybe. But that's cold comfort.
  14. Marc Zeitlin

    10/23 Raptor Video

    While the general canard community today refers to the small protrusions at the LE, below the stagnation point as vortilons, and to large flow oriented "walls", either top or bottom of the wing, usually at the TE but not always, as "fences", the standard terminology does align with your thinking...
  15. Marc Zeitlin

    10/23 Raptor Video

    They're fences, not vortilons. But in any case, they're supposed to minimize spanwise flow near the wingtips, for stability and deep stall prevention reasons. It's not at all obvious (or analyzable) what the optimum height of the fences should be - the previous size was arbitrary. So it's...
  16. Marc Zeitlin

    10/23 Raptor Video

    This will be somewhat of a diversion from the actual aircraft discussion, but it vaguely applies. Steven Levitt (he of "Freakonomics" fame) has stated numerous times that quitting can be substantially more beneficial than persisting in the face of failure. Obviously not all the time - witness...
  17. Marc Zeitlin

    Using only 4 out of 6 propeller mounting bolts

    This is an interesting question. So I'd need to be more rigorous and actually do some math (which I'm loathe to do), but here's my theory. Standard hubs - either fixed pitch, or C/S - are one piece. This means that ALL the bolts (and the surfaces under them, across the flange) that clamp the...
  18. Marc Zeitlin

    Moderator Approval Required?

    While this practice does what you posit, it MAY also violate copyrights. What is the moderators' position on that issue? i.e., to use my two (well, three) websites for example, if anyone copied pictures (or anything) from it, all of which are copyrighted per the notice at the bottom of every...
  19. Marc Zeitlin

    Who here has no need/intention to add ADS-B OUT?

    Because the ADS-B required airspace is effectively the same as transponder required airspace, and transponders are required above 10K ft. (with the 2500 ft. AGL exception). So if you need a transponder to fly somewhere, you also need ADS-B now. You'd have to go back the transponder requirement...
  20. Marc Zeitlin

    Who here has no need/intention to add ADS-B OUT?

    I have a COZY MKIV that I fly in every airspace except Class A (just haven't had a reason to go that high yet). So yes - I installed ADS-B out in my Dynon Skyview system so that I didn't ever have to think about where I could and couldn't go, and how high I could or couldn't go again.
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