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L/D?

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  • L/D?

    I'm looking for a range of best L/Ds for the patrol. Anyone got that from your fight testing?

    Mark
    Mark
    Scratch building Patrol #275
    Hood River, OR

  • #2
    http://bearhawkaircraft.com/wp-conte...ingReport.html

    Here is a link to an article where the author documents performance testing data. There are best glide speeds, sink rates, and angles of descent at various weights.
    Brooks Cone
    Southeast Michigan
    Patrol #303, Kit build

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    • #3
      Originally posted by Bcone1381 View Post
      http://bearhawkaircraft.com/wp-conte...ingReport.html

      Here is a link to an article where the author documents performance testing data. There are best glide speeds, sink rates, and angles of descent at various weights.
      He talks about exceptionally light ailerons, however some people seem to have heavier ailerons. Maybe he's talking about a low speed flight, mine certainly get heavier with increasing airspeed.
      Is there anything which the builder can change to alter the effectiveness or heaviness of the ailerons?

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      • #4
        I forgot about this thread! Brooks I did see and read that article, but it actually doesn't address my question. I'm looking for the typical best L/D (glide ratio) for a Patrol, not the speed or AoA at which it occurs. 15:1? 20:1?
        Mark
        Scratch building Patrol #275
        Hood River, OR

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        • Bcone1381
          Bcone1381 commented
          Editing a comment
          The article claims that the best glide angle is 4.65 degrees. *An online calculator says that is equal to a 12:1 rise/run or glide ratio..

        • Chewie
          Chewie commented
          Editing a comment
          Thanks, I missed that!

      • #5
        Battson, initial flights in my Patrol revealled very heavy aileron forces. So heavy, in fact, I began to question control authority in gusty conditions. The problem was my doing, however. I had the ailerons rigged about 5/16" below the wingtips, figuring air loads would bring them up to level. "Drooping" the ailerons was a bad choice. Adjusting the aileron pushrods, I raised the ailerons a bit. Forces were reduced. I then began a series of adjustments / flight tests to determine a sweet spot. I ended up with ailerons about 3/8" higher than the wingtips. I also adjusted the flaps to match the ailerons. Aileron forces are quite pleasant, but not too light.
        Now, before someone says it, I know the Patrol has the Riblett airfoil and Battson's 4 place doesn't. It workd so well on mine, it just might be worth a try.
        I reall Mark mentioning that raising the ailerons also reduces adverse yaw. I can't address the difference, but I can say that adverse yaw in my Patrol is not objectionable.

        Bill
        Last edited by Bdflies; 12-04-2017, 08:28 AM.

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        • #6
          We have always told builders to rig their ailerons about 3/8" to 1/2" above the wingtips on BOTH sides. It also reduces adverse yaw.

          The other thing builders some times do is tighten their aileron cables too tight. Lighter cable tension translates into lighter control forces. Of course you can over do it. Mark

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