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Re: [multimachine] Re: cooling concerns

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  • HB
    I don t see that making any difference in the use of old or newer air-cooled small engines They are also using modern small engines NOW without any extra
    Message 1 of 16 , May 8, 2013
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      I don't see that making any difference in the use of old or newer air-cooled small engines
      They are also using modern small engines NOW without any extra cooling modifications just like the way they did with the older engines.



      From: greg123452003 <greg123452003@...>
      To: multimachine@yahoogroups.com
      Sent: Tuesday, May 7, 2013 10:47 PM
      Subject: [multimachine] Re: cooling concerns

       


      --- In multimachine@yahoogroups.com, HB <scfpigs@...> wrote:
      >
      > Small lawnmower type engines have been extensively used for fishing boats in Southeast Asia for more than half a century without any special cooling system modifications.
      > I don't see why this is now a modern concern.
      >
      Because modern engines use much tighter clearances.



    • Eggleston Lance
      yes, I assumed scrap alloy. I am suggesting that extruded aluminum window frames, lawn chair frames, cola cans etal would not be strong enuff for
      Message 2 of 16 , May 8, 2013
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        yes, I assumed scrap alloy.

        I am suggesting that extruded aluminum window frames,
        lawn chair frames, cola cans etal <series 1000> would not be strong
        enuff for this purpose.

        Therefore use previously cast alloy wheels, small engines,
        BBQ, etal to make the props. 
        lance
        ++++
         
        On May 8, 2013, at 1:50 AM, greg123452003 wrote:

         cast from 6061 or A356
        > Al alloy. 1000 series is too weak for this purpose.

        It's going to be scrap alloy, NOT ingots! THINK third world NOT Kalifornia!

      • Adam Simmons
        I doubt it would make any difference, but the critical tolerance for heat is piston to cylinder wall -- especially since the aluminum piston expands at a
        Message 3 of 16 , May 8, 2013
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          I doubt it would make any difference, but the critical tolerance for heat is piston to cylinder wall -- especially since the aluminum piston expands at a faster rate than the surrounding steel cylinder. Older engines left a lot of space between the piston and cylinder wall, and in search for more efficient, cleaner and quieter engines they've shrunk up that tolerance over the years. 

          So, let's say they had .008" before, you probably have .005" now, and that's a big difference when it comes to overheating a motor. Now, cylinders today are much straighter, and the pistons should be designed to limit growth, but the rough idea is that smaller gap, less room to expand.

          Lets' not forget this is air directly above water, which will have a high humidity and fantastic thermal transmission capabilities, not to mention be cooler than air over land.  I don't forsee a problem.

           - Adam


          On Wed, May 8, 2013 at 1:17 AM, HB <scfpigs@...> wrote:
           

          I don't see that making any difference in the use of old or newer air-cooled small engines
          They are also using modern small engines NOW without any extra cooling modifications just like the way they did with the older engines.



          From: greg123452003 <greg123452003@...>
          To: multimachine@yahoogroups.com
          Sent: Tuesday, May 7, 2013 10:47 PM
          Subject: [multimachine] Re: cooling concerns

           


          --- In multimachine@yahoogroups.com, HB <scfpigs@...> wrote:
          >
          > Small lawnmower type engines have been extensively used for fishing boats in Southeast Asia for more than half a century without any special cooling system modifications.
          > I don't see why this is now a modern concern.
          >
          Because modern engines use much tighter clearances.




        • greg123452003
          ... I doubt that aluminum window frames, lawn chair frames or even BBQs are going to be lying around in an African village just waiting to be melted down into
          Message 4 of 16 , May 9, 2013
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            --- In multimachine@yahoogroups.com, Eggleston Lance <wheezer606@...> wrote:
            >
            > yes, I assumed scrap alloy.
            >
            > I am suggesting that extruded aluminum window frames,
            > lawn chair frames, cola cans etal <series 1000> would not be strong
            > enuff for this purpose.
            >
            > Therefore use previously cast alloy wheels, small engines,
            > BBQ, etal to make the props.
            > lance
            > ++++

            I doubt that aluminum window frames, lawn chair frames or even BBQs are going to be lying around in an African village just waiting to be melted down into propellers. And even if that was the only source of aluminum, it's not that hard to add scrap copper to make a very hard wearing alloy.
          • greg123452003
            ... However these are air-cooled motorcycle engines NOT fan-force cooled engines like lawnmowers. These motorcycle engines WILL nip up and seize if there is
            Message 5 of 16 , May 9, 2013
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              --- In multimachine@yahoogroups.com, HB <scfpigs@...> wrote:
              >
              > I don't see that making any difference in the use of old or newer air-cooled small engines
              > They are also using modern small engines NOW without any extra cooling modifications just like the way they did with the older engines.
              >

              However these are air-cooled motorcycle engines NOT fan-force cooled engines like lawnmowers. These motorcycle engines WILL nip up and seize if there is not a sufficient flow of air over them. Sure a fan and shroud can be added if needed, but it would be very useful to know what is being designed. Without knowing the parameters of the most likely boat and the intended usage this is all wild speculation.

              Is the need for a high speed boat to get to more distant fishing grounds and return in a day? Is the boat going to be trawling or even pair trawling? Is the engine needed to help push the boat through the vast expanses of introduced water weeds that are choking large parts of Lake Victoria? Without knowing what the needs are you cannot design a successful solution. And remember an unsuccessful solution wipes out the purchaser's financial viability.

              Design something that's half-baked and it will be like the tens of thousands examples of previous aid lying around Africa, Asia, the Pacific and South America, scrapped and unused.

              To provide a solution, you first need to know what to problem to be solved is.
            • michael broadbent
              While I agree with some of your remarks about knowing what one  as in mind for the end product I believe earlier posts  talked of a small motorbike engine I
              Message 6 of 16 , May 9, 2013
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                While I agree with some of your remarks about knowing what one  as in mind for the end product
                I believe earlier posts  talked of a small motorbike engine I presumed rightly or wrongly 100 to 125cc.
                With that in mind limitations are  already in place as to size of vessel and the type of journeys and use.
                         The problem you mention of weeds is already solved. I live in a 55foot narrow boat on part of the UK
                canal system .Prop fouling occurs both with weeds and rubbish and even discarded shopping trolleys.
                To free the prop there is a weed hatch which allows one to reach the prop from inside the boat.
                      With the long tail the unit if fouled can be spun through 180 degree and the prop worked on from inside the
                boat or if the unit is small the whole unit can be lifted out to work on.
                       My own thoughts are more to the materials available ,if I  require a bearing ,pipe and steel they are all within
                a 10 minute walk not so in other countries .Next is fabrication methods no good saying wield A to B if no wielding is available  or turn pipe to suit if a lathe is several days journey away. Having travelled a fair bit of the world I am intrigued to see how
                different people solve problems in different ways long may it continue.
                 
                Cheers Mike
                        
                      
                        

                 
                From: greg123452003 <greg123452003@...>
                To: multimachine@yahoogroups.com
                Sent: Thursday, 9 May 2013, 9:20
                Subject: [multimachine] Re: cooling concerns



                --- In multimachine@yahoogroups.com, HB <scfpigs@...> wrote:
                >
                > I don't see that making any difference in the use of old or newer air-cooled small engines
                > They are also using modern small engines NOW without any extra cooling modifications just like the way they did with the older engines.
                >

                However these are air-cooled motorcycle engines NOT fan-force cooled engines like lawnmowers. These motorcycle engines WILL nip up and seize if there is not a sufficient flow of air over them. Sure a fan and shroud can be added if needed, but it would be very useful to know what is being designed. Without knowing the parameters of the most likely boat and the intended usage this is all wild speculation.

                Is the need for a high speed boat to get to more distant fishing grounds and return in a day? Is the boat going to be trawling or even pair trawling? Is the engine needed to help push the boat through the vast expanses of introduced water weeds that are choking large parts of Lake Victoria? Without knowing what the needs are you cannot design a successful solution. And remember an unsuccessful solution wipes out the purchaser's financial viability.

                Design something that's half-baked and it will be like the tens of thousands examples of previous aid lying around Africa, Asia, the Pacific and South America, scrapped and unused.

                To provide a solution, you first need to know what to problem to be solved is.



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              • David G. LeVine
                ... Air cooled motor cycle engines idle at low load, at high speed there is lots of airflow, at low speed, not much. A boat will almost always be slow to
                Message 7 of 16 , May 9, 2013
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                  On 05/09/2013 04:20 AM, greg123452003 wrote:
                  > However these are air-cooled motorcycle engines NOT fan-force cooled engines like lawnmowers. These motorcycle engines WILL nip up and seize if there is not a sufficient flow of air over them. Sure a fan and shroud can be added if needed, but it would be very useful to know what is being designed. Without knowing the parameters of the most likely boat and the intended usage this is all wild speculation.

                  Air cooled motor cycle engines idle at low load, at high speed there is
                  lots of airflow, at low speed, not much. A boat will almost always be
                  slow to speed up, hence my concern for additional cooling since the
                  amount of time at slow speed will affect the engine temperature.

                  Dave 8{)
                  --

                  "A word to the wise ain't necessary - it's the stupid ones that need the
                  advice."

                  Bill Cosby
                • Adam Simmons
                  I doubt it ll be an issue. Most engines can take heat abuse for quite a while before there are issues. I ve ran a junkyard assembled Chevy 350 (different
                  Message 8 of 16 , May 9, 2013
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                    I doubt it'll be an issue.  Most engines can take heat abuse for quite a while before there are issues.

                    I've ran a junkyard assembled Chevy 350 (different pistons, different heads, different compression ratios) on a run stand with no load, and no coolant. WOT was controlled by a string with a spare piston on it. After 10 minutes, we started wondering how long it would run.  The RPM was controlled by valve float - roughly 6500.  After another 5, it started to have heating issues,  at around 20 it finally stopped.  

                    An engine designed to be air cooled would last much longer, even sitting still.  


                    On Thu, May 9, 2013 at 11:03 AM, David G. LeVine <dlevine@...> wrote:
                     

                    On 05/09/2013 04:20 AM, greg123452003 wrote:
                    > However these are air-cooled motorcycle engines NOT fan-force cooled engines like lawnmowers. These motorcycle engines WILL nip up and seize if there is not a sufficient flow of air over them. Sure a fan and shroud can be added if needed, but it would be very useful to know what is being designed. Without knowing the parameters of the most likely boat and the intended usage this is all wild speculation.

                    Air cooled motor cycle engines idle at low load, at high speed there is
                    lots of airflow, at low speed, not much. A boat will almost always be
                    slow to speed up, hence my concern for additional cooling since the
                    amount of time at slow speed will affect the engine temperature.

                    Dave 8{)
                    --

                    "A word to the wise ain't necessary - it's the stupid ones that need the
                    advice."

                    Bill Cosby


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