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Re: [bolger] Aluminium masts

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  • GHC
    Oh yeah, the higher temper the higher strength. 6061-T0 is 18,000 psi yield strength and -T6 is 45,000. Actually 2024 is better stuff 2024-T0 is 27,000 psi
    Message 1 of 15 , Jul 1, 2000
      Oh yeah, the higher temper the higher strength. 6061-T0 is 18,000 psi
      yield strength and -T6 is 45,000. Actually 2024 is better stuff 2024-T0 is
      27,000 psi and -T6 is 69,000 psi. You can use the mast programs on the
      carlsondesign.com website and figure the psi load under various
      configurations and estimate your safety factor. By the way, I find
      strengths of Douglas Fir at about 14,000 max. most other woods a little less

      T6 is a common temper, but is, of course brittle. So, they will form (e.g.
      tapering) at the lowest (annealed) temper because it's easiest on the the
      tooling and energy budget. Then, they will temper. I think my flagpoles
      were tempered 2024.

      My poles are pretty thick - about .125 wall, thicker at the top. The loads
      on poles are really similar to masts - they are rated in mph windload vs.
      flag size. You might guess they go up to about 100 or 120 mph, so, all in
      all, it's a roughly similar solution to a similar problem. In other words,
      if you just traded a (free-standing) mast with an engineered flagpole of
      similar length, you are not going to be far off.

      My light schooner masts were wooden, 3.5" diameter. The 16' flagpoles I
      wanted to use were either 3" or 2-7/8" O.D. If you play with the programs,
      you'll see the wooden mast is a just little stronger, or that it has a
      larger factor of safety. However, you have got to admit that aluminum is a
      lot more uniform material than knotty old 2x4's, so I considered it a wash.

      Plus, I was also willing to take the chance of buckling a $200 pole. In
      practice, it has worked great in all kind of wind, and yes, you can see
      them bend a little.

      Of course, two things to consider - give the tubing some protection around
      the mast partners, because it wants to buckle there. And, don't drill any
      holes near the partners that will start a crack. In truth, the pole mast
      with a little heliarcing might be ideal.

      I thought about a straight tube with a 4' turned wood taper on top, but
      finding precision Al. tubing is harder than finding flagpoles. And, al.
      conduit is worthless.

      GHC




      At 05:20 PM 7/1/2000 -0500, you wrote:
      >Gregg, Ed says: "Sch 40 is high-temper 6061, harder than flagpoles.", do you
      >think that's relevant? I would use wood for the gaff & boom jaws, but wear
      >would be still be an issue.
      >
      >Is the load on a mast that much more than the load on a flagpole? You said
      >you wrote a program that determined that wood was stiffer, but that the
      >aluminum flagpole masts on your schooner (obligatoryBolger reference) were
      >strong enough. Has this been born out in real world testing?
      >
      >When I looked at your masts, it seemed they were awfull thin, just how thick
      >are they? 1/8inch, 14 gauge?
      >
      >On these tapered flagpoles, the walls on the top are thicker than on the
      >bottom, probably because they take a tube and role the taper in. This would
      >seem to me to indicate the weight on the top of the tapered mast is the same
      >as the weight of the untapered pipe. With this in mind, would it be cheaper
      >to just buy aluminum tubing of the appropriate diameter and not worry about
      >the taper?
      >
      >Wonder if your local flagpole company would sell a strait tube?
      >
      >----- Original Message -----
      >From: "GHC" <ghartc@...>
      >To: <bolger@egroups.com>
      >Sent: Saturday, July 01, 2000 4:48 PM
      >Subject: Re: [bolger] Aluminium masts
      >
      >
      >> I ordered two tapered flag poles from a local flag shop for my light
      >> scooner. I believe they were 16 footers, but if you needed them fatter,
      >> you could order 20's and cut the tips off - etc. About $200 each.
      >>
      >> Gregg Carlson
      >> http://www.carlsondesign.com/lscooner.html
      >>
      >> At 03:59 PM 7/1/2000 -0500, you wrote:
      >> >I'm considering the same mod for Entropy.
      >> >
      >> >> much smaller, perhaps 2 or 2-1/2". Sch 40 is high-temper 6061, harder
      >than
      >> >> flagpoles.
      >> >>
      >> >> ED HAILE
      >
      >
      >
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    • Lincoln Ross
      ... Depends on what you mean by brittle. Of course if you do all sorts of forming it will crack, but I think in use it probably won t. I have a 25 year old
      Message 2 of 15 , Jul 1, 2000
        --- In bolger@egroups.com, GHC <ghartc@p...> wrote:
        > snip
        > T6 is a common temper, but is, of course brittle.
        Depends on what you mean by brittle. Of course if you do all sorts of
        forming it will crack, but I think in use it probably won't. I have a
        25 year old bicycle frame from 6061 T6 (tempered after welding) that
        has been crashed at least twice without damage (to the frame, I'm not
        talking about me or the wheels).

        I suspect you need to consider corrosion properties of different
        alloys. I recall that 2024 is not so great for this, and that there
        are specific marine alloys.
      • G Carlson
        You re right, brittle is overstated, 2024-T6 and 6061-T6 are good stuff. So, probably, are 6063 and 7075. I believe the flag poles are anodized, or available
        Message 3 of 15 , Jul 1, 2000
          You're right, "brittle" is overstated, 2024-T6 and 6061-T6 are good stuff.
          So, probably, are 6063 and 7075.

          I believe the flag poles are anodized, or available with. I think, in
          practice, you'll probably take what you can get - no choice at all on
          flagpole materials. In fact, the scope and properties across vendors were
          so identical there's probably a single manufacturer.

          I was really surprised actually by the scarcity and expense of precision
          tubing, and there's a fair amount of aerospace acitivity here (Tulsa, OK).

          Anyway, my spars have been excellent - light, hollow - less windage and
          weight aloft, but there's been little relative interest in doing it this
          way, for some reason. Oh well.

          As an aside, I am have been looking for a trapeze set to set off the
          scooner's main mast - should be fun.

          Gregg Carlson


          >--- In bolger@egroups.com, GHC <ghartc@p...> wrote:
          >> snip
          >> T6 is a common temper, but is, of course brittle.
          >Depends on what you mean by brittle. Of course if you do all sorts of
          >forming it will crack, but I think in use it probably won't. I have a
          >25 year old bicycle frame from 6061 T6 (tempered after welding) that
          >has been crashed at least twice without damage (to the frame, I'm not
          >talking about me or the wheels).
          >
          >I suspect you need to consider corrosion properties of different
          >alloys. I recall that 2024 is not so great for this, and that there
          >are specific marine alloys.
          >
          >
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          >Bolger rules!!!
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        • G Carlson
          Can anyone part with this issue (26:40) covering Herreschoff s Rozinante? (There are other issues of similar interest including Red Head 123:58 124:6 114:32
          Message 4 of 15 , Jul 1, 2000
            Can anyone part with this issue (26:40) covering Herreschoff's Rozinante?

            (There are other issues of similar interest including "Red Head" 123:58
            124:6 114:32 and 56:38)

            Thanks, Gregg Carlson
          • chris
            hi Guys.. Greg It is funny that you mention the aerospace Industry... I just got Three mast ( poles) myself from my brother in law that works at a large (
            Message 5 of 15 , Jul 1, 2000
              hi Guys.. Greg It is funny that you mention the aerospace Industry... I
              just got Three mast ( poles) myself from my brother in law that works at a
              large ( multinational) aluminum extruder.. they supply aluminum tubing for
              areospace and airline manufactures ... the tubes that I got were a mixture
              of aluminum-titanium-magnesium (spelling?) they were seconds that were going
              for scrap. they are 28 feet long- 3 1/2 inches in diameter- and .132 walls.
              they were suppose to be .125, that is why they were heading for the scrap
              pile... I paid 120 bucks for all three ( one dollar a pound) I sold one to
              Dave Gray for "foolhardy" and am keeping the other two for my Light Schooner
              ( when I get aroung to building it)
              ----- Original Message -----
              From: "G Carlson" <ghartc@...>
              To: <bolger@egroups.com>
              Sent: Saturday, July 01, 2000 11:28 PM
              Subject: Re: [bolger] Re: Aluminium masts


              > You're right, "brittle" is overstated, 2024-T6 and 6061-T6 are good stuff.
              > So, probably, are 6063 and 7075.
              >
              > I believe the flag poles are anodized, or available with. I think, in
              > practice, you'll probably take what you can get - no choice at all on
              > flagpole materials. In fact, the scope and properties across vendors were
              > so identical there's probably a single manufacturer.
              >
              > I was really surprised actually by the scarcity and expense of precision
              > tubing, and there's a fair amount of aerospace acitivity here (Tulsa, OK).
              >
              > Anyway, my spars have been excellent - light, hollow - less windage and
              > weight aloft, but there's been little relative interest in doing it this
              > way, for some reason. Oh well.
              >
              > As an aside, I am have been looking for a trapeze set to set off the
              > scooner's main mast - should be fun.
              >
              > Gregg Carlson
              >
              >
              > >--- In bolger@egroups.com, GHC <ghartc@p...> wrote:
              > >> snip
              > >> T6 is a common temper, but is, of course brittle.
              > >Depends on what you mean by brittle. Of course if you do all sorts of
              > >forming it will crack, but I think in use it probably won't. I have a
              > >25 year old bicycle frame from 6061 T6 (tempered after welding) that
              > >has been crashed at least twice without damage (to the frame, I'm not
              > >talking about me or the wheels).
              > >
              > >I suspect you need to consider corrosion properties of different
              > >alloys. I recall that 2024 is not so great for this, and that there
              > >are specific marine alloys.
              > >
              > >
              > >------------------------------------------------------------------------
              > >Lonely? Get Firetalk!
              > >Free, unlimited calls anywhere in the world.
              > >Free voice chat on hundreds of topics.
              > >http://click.egroups.com/1/5477/13/_/3457/_/962504449/
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              > >
              > >Bolger rules!!!
              > >- no cursing
              > >- stay on topic
              > >- use punctuation
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              > >- add some content: send "thanks!" and "ditto!" posts off-list.
              >
              >
              >
              >
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              > Bolger rules!!!
              > - no cursing
              > - stay on topic
              > - use punctuation
              > - add your comments at the TOP and SIGN your posts
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              >
            • chris
              month year????? ... From: G Carlson To: Sent: Saturday, July 01, 2000 11:31 PM Subject: Re: [bolger] Woodenboat
              Message 6 of 15 , Jul 1, 2000
                month year?????

                ----- Original Message -----
                From: "G Carlson" <ghartc@...>
                To: <bolger@egroups.com>
                Sent: Saturday, July 01, 2000 11:31 PM
                Subject: Re: [bolger] Woodenboat No. 26:40


                > Can anyone part with this issue (26:40) covering Herreschoff's Rozinante?
                >
                > (There are other issues of similar interest including "Red Head" 123:58
                > 124:6 114:32 and 56:38)
                >
                > Thanks, Gregg Carlson
                >
                >
                >
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                >
                > Bolger rules!!!
                > - no cursing
                > - stay on topic
                > - use punctuation
                > - add your comments at the TOP and SIGN your posts
                > - add some content: send "thanks!" and "ditto!" posts off-list.
                >
              • Jim Goeckermann
                Greg, Would a copy of that article do, or a loan of the magazine so that you can read something, or do you just want to have your own? Jim
                Message 7 of 15 , Jul 1, 2000
                  Greg,
                  Would a copy of that article do, or a loan of the magazine so that you can
                  read something, or do you just want to have your own?
                  Jim

                  G Carlson wrote:

                  > Can anyone part with this issue (26:40) covering Herreschoff's Rozinante?
                  >
                  > (There are other issues of similar interest including "Red Head" 123:58
                  > 124:6 114:32 and 56:38)
                  >
                  > Thanks, Gregg Carlson
                  >
                  > ------------------------------------------------------------------------
                  > Free, Unlimited Calls Anywhere!
                  > Visit Firetalk.com - click below.
                  > http://click.egroups.com/1/5479/13/_/3457/_/962512655/
                  > ------------------------------------------------------------------------
                  >
                  > Bolger rules!!!
                  > - no cursing
                  > - stay on topic
                  > - use punctuation
                  > - add your comments at the TOP and SIGN your posts
                  > - add some content: send "thanks!" and "ditto!" posts off-list.
                • Lincoln Ross
                  Just recalled re an extruder that we use at work. I won t tell you the name of his outfit because I don t know if he d appreciate the extra business just now.
                  Message 8 of 15 , Jul 2, 2000
                    Just recalled re an extruder that we use at work. I won't tell you
                    the
                    name of his outfit because I don't know if he'd appreciate the extra
                    business just now. Try to find an extrusion place far from
                    electronics
                    firms. If I recall, extrusion dies don't cost very much these days, I
                    think less than $1k. I'll bet if 10 Micro builders got together you
                    could (if one of you was a mechanical engineering type order a die,
                    with the size correct and a bolt rope groove or (aluminum) track
                    integral, and have masts made up. Of course there would be no taper.
                    I
                    have a suspicion there is something wrong with this notion, but I
                    don't know what.

                    Red Zinger uses a flagpole mast these days.
                    snip
                  • Roger Dewhurst
                    I have calculated the euler load on various lengths of aluminium tube of different diameters. I have used a recent version of a Works for Windows spreadsheet.
                    Message 9 of 15 , Jul 2, 2000
                      I have calculated the euler load on various lengths of aluminium tube of
                      different diameters. I have used a recent version of a Works for Windows
                      spreadsheet. Euler theory is commonly used to calculate the stress on end
                      loaded spars, which a stayed mast is.

                      R
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