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Re: QUESTIONS

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  • ph_dutoit
    Good day all. First of all, thank you for the replies to my questions. I have done a bit of reading in the meantime, and learnt the following: Mat Redsell of
    Message 1 of 11 , Jun 1, 2010
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      Good day all.

      First of all, thank you for the replies to my questions. I have done a bit of reading in the meantime, and learnt the following:

      Mat Redsell of marske flying wings fame suggests a CoG range 17-24% MAC. He also reckons a flying wing can tumble if the CoG approaches 50% MAC.

      Dan Raymer suggests a CoG range 25-30% MAC, but reckons 30% is only done after windtunnel evaluation(in our case a no-go then).

      The reason for these questions is that I'm toying with the idea of a flying wing type airchair. Possible pro's are the following:

      1. Greater transportability. I love my Goat 4, but it can be a pain to transport. I dont know how Mike Sandlin gets the wings on top of his truck alone.... I was thinking a 3-piece wing, of say 12 ft segments.

      2. A little less weight, due to the missing tail. It seems to me that for our type of flying a saving in weight can result in a fair gain in performance, maybe more so than trying to reduce drag. It also allows more space to add a small engine.

      3. A lighter wing, since reflexed wings apparently align themselves with the airflow (gusts), you don't have to design to 9 g's.

      4. Flying wings look cool, especially with some forward sweep ;-)

      5. Lower cost due to less materials used.

      I know reflexed airfoils do have a lower Cl, but I reckon the other savings will make up for this.

      Any thoughts on this matter?

      Regards
      Pieter
    • ¹Î¼®
      Hi Pieter, Single person car top loading of the Goat wing is a big issue and is a problem that others have encountered, as I am sure you know. I thought that
      Message 2 of 11 , Jun 1, 2010
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        Hi Pieter,

        Single person car top loading of the Goat wing is a big issue and is a problem that others have encountered, as I am sure you know. I thought that the original Goat1 wing half, with attached struts and cabane (about 42 lbs.), was beyond my lifting weight limits for something of that shape, especially in wind. Since then I have designed Goats with either removbale struts/cabanes (Goat3) or cable bracing. I used to lift and load hang gliders that were heavy, perhaps over 70 lbs., but those had handles and weren't big wind vanes.


        Floyd Fronius converted the Red Goat struts to make them removable during trasport, partly, I suppose, to reduce the lifting weight of the wing panels.

        Your wing, Pieter, has no struts but has extra span and a lot of wood, so I presume it might be heavier than the Goat1 wing. and if so I can understand the desire for something more liftable.

        Better Goat transportability could be best achieved, I think, by avoiding weight and size increases to the main wing, and using removable struts and cabanes. More removable parts will add complexity to the setup, but minimizing the size and weight of the wing panels might be worth it. The best thing of all, of course, would be airport storage and a tow service, but this is rare except in our dreams.

        Best regards,

        Mike Sandlin......San Diego California

        --- In Airchairgroup@yahoogroups.com, "ph_dutoit" <pieterhdutoit@...> wrote:
        ........................
        > 1. Greater transportability. I love my Goat 4, but it can be a pain to transport. I dont know how Mike Sandlin gets the wings on top of his truck alone.... I was thinking a 3-piece wing, of say 12 ft segments.
        >
        >
        > Regards
        > Pieter
        >
      • Phils
        Well It depends on your strength as to what is easy to lift. Car top loading to me is in its own right is difficult with nearly anything..... and I
        Message 3 of 11 , Jun 2, 2010
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          Well It depends on your strength as to what is "easy" to lift.
          Car top loading to me is in its own right is difficult with nearly anything..... and I can bench press 300 lbs. But I'm short too. I think anyone with serious desires to build and fly Airchairs Should look into getting a trailer to haul it on. Even better, maybe a box trailer as you will more than likely WANT to go fly other places. What better way than to outfit your box into a camping RV toy hauler kind'a thing that protects you AND your hard work .
          Being easy to load means one can design it with that in mind. For me trailering is a given , I cant function without a trailer.


          --- In Airchairgroup@yahoogroups.com, ¹Î¼® <ms7525@...> wrote:
          >
          >
          >
          > Hi Pieter,
          >
          > Single person car top loading of the Goat wing is a big issue and is a problem that others have encountered, as I am sure you know. I thought that the original Goat1 wing half, with attached struts and cabane (about 42 lbs.), was beyond my lifting weight limits for something of that shape, especially in wind. Since then I have designed Goats with either removbale struts/cabanes (Goat3) or cable bracing. I used to lift and load hang gliders that were heavy, perhaps over 70 lbs., but those had handles and weren't big wind vanes.
          >
          >
          > Floyd Fronius converted the Red Goat struts to make them removable during trasport, partly, I suppose, to reduce the lifting weight of the wing panels.
          >
          > Your wing, Pieter, has no struts but has extra span and a lot of wood, so I presume it might be heavier than the Goat1 wing. and if so I can understand the desire for something more liftable.
          >
          > Better Goat transportability could be best achieved, I think, by avoiding weight and size increases to the main wing, and using removable struts and cabanes. More removable parts will add complexity to the setup, but minimizing the size and weight of the wing panels might be worth it. The best thing of all, of course, would be airport storage and a tow service, but this is rare except in our dreams.
          >
          > Best regards,
          >
          > Mike Sandlin......San Diego California
          >
          > --- In Airchairgroup@yahoogroups.com, "ph_dutoit" <pieterhdutoit@> wrote:
          > ........................
          > > 1. Greater transportability. I love my Goat 4, but it can be a pain to transport. I dont know how Mike Sandlin gets the wings on top of his truck alone.... I was thinking a 3-piece wing, of say 12 ft segments.
          > >
          > >
          > > Regards
          > > Pieter
          > >
          >
        • Mark
          At some Hang Gliding sites, pulling a camping trailer to the top to launch is impossible or at least improbable. You are unlikely to find a ride up with
          Message 4 of 11 , Jun 3, 2010
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            At some Hang Gliding sites, pulling a camping trailer to the top to launch is impossible or at least improbable. You are unlikely to find a ride up with somebody else. If you had a light box trailer, it may be possible. Plus you can offer Hang Glider pilots, and their wings, a ride to the top.
            My $.03 (inflation makes $.02 worthless)
            Mark

            --- In Airchairgroup@yahoogroups.com, "Phils" <philsconcepts@...> wrote:
            >
            > Well It depends on your strength as to what is "easy" to lift.
            > Car top loading to me is in its own right is difficult with nearly anything..... and I can bench press 300 lbs. But I'm short too. I think anyone with serious desires to build and fly Airchairs Should look into getting a trailer to haul it on. Even better, maybe a box trailer as you will more than likely WANT to go fly other places. What better way than to outfit your box into a camping RV toy hauler kind'a thing that protects you AND your hard work .
            > Being easy to load means one can design it with that in mind. For me trailering is a given , I cant function without a trailer.
            >
          • tjwardx
            ... The obvious solution to this is to find a used Pterodactyl ultralight. Without the engine and prop, it should fold up into quite a compact package. Tim
            Message 5 of 11 , Jun 3, 2010
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              --- In Airchairgroup@yahoogroups.com, "ph_dutoit" <pieterhdutoit@...> wrote:

              > The reason for these questions is that I'm toying with the idea of a flying wing type airchair.


              The obvious solution to this is to find a used Pterodactyl ultralight.
              Without the engine and prop, it should fold up into quite a compact package.


              Tim Ward
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