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Re: Friction loss

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  • Tony Foale
    Ref: Harley tests. The speed difference is around 6.5 to 7% depending on the base choosen for the percentage. This represents a difference in power of 19 to
    Message 1 of 24 , Nov 24, 2007
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      Ref: Harley tests.

      The speed difference is around 6.5 to 7% depending on the base choosen for the percentage.  This represents a difference in power of 19 to 22% again depending on the base (belt or chain).

      However, this does not mean that the chain lost 19 to 22 % more than the belt.  It depends on the shape of the power curve and where we are on it.
      Just a small increase in friction loss will cause the bike to run a bit slower but if it happens to be on a steep part of the power curve then engine power will have dropped and so the bike will run slower still and then the power will be reduced a bit more and the bike will run even slower until there is an equilibrium between total drag power and power at the wheel.

      So just a small increase in drive friction may have a disproportionate effect on measured speed.  In order to make the tests truely valid as an indicator of the difference between the two drive systems it would be necessary to gear the chain drive machine to produce the same RPM at max velocity as with the belt drive machine.  Then the difference in velocity would be less.

      To return to the original question about the value of reducing friction in an engine, the answer is yes it can be worthwhile.  Friction loss is considerable and modern racing engines which take advantage of modern surface treatments and coatings can cut friction losses in half.  Unfortunately this doesn't come cheap, but there are other things that can be done without much cost.

      --
      Regards

      Tony Foale
      info@...
      www.tonyfoale.com
    • Otto Nikolaus
      HI Tony, Correct, of course, but there is another issue here, isn t there? Have we not always been told how efficient chains are? 98% IIRC for a new, well
      Message 2 of 24 , Nov 24, 2007
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        HI Tony,

        Correct, of course, but there is another issue here, isn't there?

        Have we not always been told how efficient chains are? 98% IIRC for a new, well lubed chain on new sprockets. Assuming that a belt can improve on this, which I doubt, then we have less than 2% loss to play with anyway. I don't see how that could translate to a 6-7% speed gain no matter how steep the power curve, and certainly not for a Harley.

        Again if this improvement were real, belts would have replaced chains on most bikes surely?

        Otto

        On 24/11/2007, Tony Foale < tonyfoale@...> wrote:
        Ref: Harley tests.

        The speed difference is around 6.5 to 7% depending on the base choosen for the percentage.  This represents a difference in power of 19 to 22% again depending on the base (belt or chain).

        However, this does not mean that the chain lost 19 to 22 % more than the belt.  It depends on the shape of the power curve and where we are on it.
        Just a small increase in friction loss will cause the bike to run a bit slower but if it happens to be on a steep part of the power curve then engine power will have dropped and so the bike will run slower still and then the power will be reduced a bit more and the bike will run even slower until there is an equilibrium between total drag power and power at the wheel.

        So just a small increase in drive friction may have a disproportionate effect on measured speed.  In order to make the tests truely valid as an indicator of the difference between the two drive systems it would be necessary to gear the chain drive machine to produce the same RPM at max velocity as with the belt drive machine.  Then the difference in velocity would be less.

        To return to the original question about the value of reducing friction in an engine, the answer is yes it can be worthwhile.  Friction loss is considerable and modern racing engines which take advantage of modern surface treatments and coatings can cut friction losses in half.  Unfortunately this doesn't come cheap, but there are other things that can be done without much cost.


      • Danny Whitfield
        ... One other detail that I failed to mention is that the belt drive Harley also used a toothed belt primary drive instead of double row chain. Also, the
        Message 3 of 24 , Nov 24, 2007
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          On 11/24/07, Otto Nikolaus <otto.nikolaus@...> wrote:

          HI Tony,

          Correct, of course, but there is another issue here, isn't there?

          Have we not always been told how efficient chains are? 98% IIRC for a new, well lubed chain on new sprockets. Assuming that a belt can improve on this, which I doubt, then we have less than 2% loss to play with anyway. I don't see how that could translate to a 6-7% speed gain no matter how steep the power curve, and certainly not for a Harley.

          Again if this improvement were real, belts would have replaced chains on most bikes surely?

           
          One other detail that I failed to mention is that the belt drive Harley also used a toothed belt primary drive instead of double row chain.   Also, the belt bike's overall ratio was slightly higher than the chain bike's.
           
          Dan Whitfield

           

          Otto



          On 24/11/2007, Tony Foale < tonyfoale@... > wrote:
          Ref: Harley tests.

          The speed difference is around 6.5 to 7% depending on the base choosen for the percentage.  This represents a difference in power of 19 to 22% again depending on the base (belt or chain).

          However, this does not mean that the chain lost 19 to 22 % more than the belt.  It depends on the shape of the power curve and where we are on it.
          Just a small increase in friction loss will cause the bike to run a bit slower but if it happens to be on a steep part of the power curve then engine power will have dropped and so the bike will run slower still and then the power will be reduced a bit more and the bike will run even slower until there is an equilibrium between total drag power and power at the wheel.

          So just a small increase in drive friction may have a disproportionate effect on measured speed.  In order to make the tests truely valid as an indicator of the difference between the two drive systems it would be necessary to gear the chain drive machine to produce the same RPM at max velocity as with the belt drive machine.  Then the difference in velocity would be less.

          To return to the original question about the value of reducing friction in an engine, the answer is yes it can be worthwhile.  Friction loss is considerable and modern racing engines which take advantage of modern surface treatments and coatings can cut friction losses in half.  Unfortunately this doesn't come cheap, but there are other things that can be done without much cost.


           


        • John Fisher
          OK so the comparison is interesting but dubious. Just as a thought experiment, how would one set up a convincing test? for instance, the drive ratio has to be
          Message 4 of 24 , Nov 24, 2007
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            OK so the comparison is interesting but dubious. Just as a thought
            experiment, how would one set up a convincing test?

            for instance, the drive ratio has to be the same for both, but what
            about the sprocket sizes, do you use the same diameters, or do you
            optimize each system to diameters that work best?
            What about measuring power output, could you use a well-regulated
            electric motor to drive an alternator, then measuring output? Or would
            you end up learning more about the alternator's efficiency than the
            drive system?
            seems a bit more complex than I thought at first.
            John

            Danny Whitfield wrote
            >
            >> One other detail that I failed to mention is that the belt drive Harley also
            >> used a toothed belt primary drive instead of double row chain. Also, the
            >> belt bike's overall ratio was slightly higher than the chain bike's.
            >>
            >> Dan Whitfield
            >>
            >>
            >>
            >>
          • Hans Passberger
            which other things??
            Message 5 of 24 , Nov 25, 2007
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              which other things??

              Tony Foale wrote:
              > Unfortunately this doesn't come cheap, but there are other things that
              > can be done without much cost.
            • A. Kovatsch
              first, you must be a bit more specific while revealing us your task or idea, as tons of books are written about reducing friction in motors/engines, and it is
              Message 6 of 24 , Nov 25, 2007
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                first, you must be a bit more specific while revealing us your
                task or idea, as tons of books are written about reducing friction
                in motors/engines, and it is different if you are trying to do
                wonders with some engine from the seventies or you are trying
                to fix engineering errors on some '07 yamaha engine ;o)

                ...because, in one case you may have access to technologies
                and knowledge that were not available to people that designed
                the engine long time ago, and in second case you maybe have a
                chance to find spots where engineers used parts that appear on their
                other models and were designed to meet requirements of several
                different engines, hence some can be of sub optimal design on some
                products, in simple words, they made some compromises for the
                sake of technology, ease and/or cost of production, etc., etc., and
                your restraints may be different from those of a factory.

                friction is basically dependent on quotient of friction, contact pressure
                (force) and velocities of parts involved, and you need to recognize what
                generates each in your case. here I assume that you are interested in
                reducing friction in order to have a more efficient engine and you mentioned
                nothing about reducing mechanical losses in general, because a decent
                percent of power is lost for accelerating masses etc., etc...

                quotient of friction you can vary with surface quality, machining dimensions,
                switching from sliding friction to rolling (like rocker arms with wheels or simple
                sliders), different lubricant (going for a better make of components is usually
                an improvement, in oils, shaft seals, chains, sprockets, belts, bearings,
                everything), different materials sometimes, as they don't all react equally
                when it may come to friction, contact pressure you can vary with geometry
                of components, geometry of their motion, their weight and velocity etc., etc...

                the discussion here went in direction of "chain vs belt", but in line with the
                above, there are details in make and execution in each that can render a
                product "high efficiency" or not. I have a friend who works as a designer
                of lightweight aircraft and motorized kites, and he could talk about belt
                drives for hours as it is one of the most relevant sub assemblies on a
                motorized kite. "High efficiency" belt drive (minimized mechanical losses
                in power transmission) may demand a special maker of the belt, special
                design of teeth on that belt that requires special teeth design on the pulley,
                special grade of aluminum for it, surface quality effects etc., etc., I just remembered
                that pulley had a lathe machined groove over all the teeth so that air doesn't
                get trapped in between the wide belt and the pulley which generates whistling
                which is a sound of mechanical loss, etc., etc...

                someone mentioned running wheels without shaft seals on bearings and I'd like
                to mention that application of any "friction reducing actions" may depend on
                your decision where do you want your motor to be in between reliability and
                efficiency (too much lubricant (grease) can increase mechanical losses
                indirectly, decrease cooling, increase sizes, increase friction, increase wear,
                etc.; too smooth surfaces may not hold lubricant, smaller area sliding surfaces
                may lead to increased loads, etc., etc...)

                Two years ago I was designing a product that was labeled "high efficiency",
                and it was an improvement of the product we already had as standard and my job
                was to be done with minimum of investment. to get the high efficiency that the customer
                demanded on the overall product, we needed to save about a kilowatt on already
                existing ~100kW in an electric motor and I went for the shaft seals expecting to find
                my luck there. Immediately I went for the better make of shaft seals and it removed
                around a kW of losses but I wasn't satisfied, so I read all of the technical instructions
                provided by both shaft seal manufacturers. they both prescribed the same tolerance
                field of the diameter of the machined shaft and both demanded the same surface quality,
                and it was grinding. the acceptable diameters of batch of shafts were several 1/100 mm
                around 2/10 mm below the nominal diameter of the shaft on the shaft seal place. so I spoke
                to the operator of the grinding machine, and he said that, once he sets the machine, he can
                easily group all the shafts from the batch in an area of 3/1000 mm around the given dimension.
                So, I did not prescribe the shaft diameter as loose around a dimension as the shaft
                seal manufacturers prescribed, but from minimal diameter they prescribed as good for
                sealing to 3/1000 above it (and not all several 1/100 mm, you see, attention and accuracy
                is what certainly helps), grouping the shaft seal diameter on all shafts in the batch on the
                lower border of still good dimension.... I remember around extra 400W saved on 100 kW
                3000 rpm electric motor, all being tested on one, same motor in one day, the shaft diameter
                was originally machined to the top value diameter of the "previously acceptable" tolerance field,
                and grinding it again (putting it back on the machine) was removing minimum 2/100 mm
                and more, to the lower border.

                So, the difference between a good motor and high efficiency one was a changed tolerance
                field on the rotor machining drawing and extra ~1 euro for more expensive shaft seals. In your
                case, it is very little likely that you will reach all your desired progress on one component only,
                it is more likely that you will get a little on several components and sub assemblies and so it
                then piles up, I could, for example, reduce these losses even further by reducing the fan size,
                but it had to be used for some other models. ;o)

                the method of turning the engine using an electric motor in order to discover and measure the
                losses of each sub assembly and measure the improvement after modifications has a name
                in english, I think.

                there's more to this but here I'll choose to seize
                my opportunity to wish a nice day to everyone,

                sascha
                http://www.jestartech.com










                Hans Passberger wrote:

                > which other things??
                >
                > Tony Foale wrote:
                > > Unfortunately this doesn't come cheap, but there are other things that
                > > can be done without much cost.
                >
              • A. Kovatsch
                first, you must be a bit more specific while revealing us your task or idea, as tons of books are written about reducing friction in motors/engines, and it is
                Message 7 of 24 , Nov 25, 2007
                • 0 Attachment
                  first, you must be a bit more specific while revealing us your
                  task or idea, as tons of books are written about reducing friction
                  in motors/engines, and it is different if you are trying to do
                  wonders with some engine from the seventies or you are trying
                  to fix engineering errors on some '07 yamaha engine ;o)

                  ...because, in one case you may have access to technologies
                  and knowledge that were not available to people that designed
                  the engine long time ago, and in second case you maybe have a
                  chance to find spots where engineers used parts that appear on their
                  other models and were designed to meet requirements of several
                  different engines, hence some can be of sub optimal design on some
                  products, in simple words, they made some compromises for the
                  sake of technology, ease and/or cost of production, etc., etc., and
                  your restraints may be different from those of a factory.

                  friction is basically dependent on quotient of friction, contact pressure
                  (force) and velocities of parts involved, and you need to recognize what
                  generates each in your case. here I assume that you are interested in
                  reducing friction in order to have a more efficient engine and you mentioned
                  nothing about reducing mechanical losses in general, because a decent
                  percent of power is lost for accelerating masses etc., etc...

                  quotient of friction you can vary with surface quality, machining dimensions,
                  switching from sliding friction to rolling (like rocker arms with wheels or simple
                  sliders), different lubricant (going for a better make of components is usually
                  an improvement, in oils, shaft seals, chains, sprockets, belts, bearings,
                  everything), different materials sometimes, as they don't all react equally
                  when it may come to friction, contact pressure you can vary with geometry
                  of components, geometry of their motion, their weight and velocity etc., etc...

                  the discussion here went in direction of "chain vs belt", but in line with the
                  above, there are details in make and execution in each that can render a
                  product "high efficiency" or not. I have a friend who works as a designer
                  of lightweight aircraft and motorized kites, and he could talk about belt
                  drives for hours as it is one of the most relevant sub assemblies on a
                  motorized kite. "High efficiency" belt drive (minimized mechanical losses
                  in power transmission) may demand a special maker of the belt, special
                  design of teeth on that belt that requires special teeth design on the pulley,
                  special grade of aluminum for it, surface quality effects etc., etc., I just remembered
                  that pulley had a lathe machined groove over all the teeth so that air doesn't
                  get trapped in between the wide belt and the pulley which generates whistling
                  which is a sound of mechanical loss, etc., etc...

                  someone mentioned running wheels without shaft seals on bearings and I'd like
                  to mention that application of any "friction reducing actions" may depend on
                  your decision where do you want your motor to be in between reliability and
                  efficiency (too much lubricant (grease) can increase mechanical losses
                  indirectly, decrease cooling, increase sizes, increase friction, increase wear,
                  etc.; too smooth surfaces may not hold lubricant, smaller area sliding surfaces
                  may lead to increased loads, etc., etc...)

                  Two years ago I was designing a product that was labeled "high efficiency",
                  and it was an improvement of the product we already had as standard and my job
                  was to be done with minimum of investment. to get the high efficiency that the customer
                  demanded on the overall product, we needed to save about a kilowatt on already
                  existing ~100kW in an electric motor and I went for the shaft seals expecting to find
                  my luck there. Immediately I went for the better make of shaft seals and it removed
                  around a kW of losses but I wasn't satisfied, so I read all of the technical instructions
                  provided by both shaft seal manufacturers. they both prescribed the same tolerance
                  field of the diameter of the machined shaft and both demanded the same surface quality,
                  and it was grinding. the acceptable diameters of batch of shafts were several 1/100 mm
                  around 2/10 mm below the nominal diameter of the shaft on the shaft seal place. so I spoke
                  to the operator of the grinding machine,  and he said that, once he sets the machine, he can
                  easily group all the shafts from the batch in an area of 3/1000 mm around the given dimension.
                  So, I did not prescribe the shaft diameter as loose around a dimension as the shaft
                  seal manufacturers prescribed, but from minimal diameter they prescribed as good for
                  sealing to 3/1000 above it (and not all several 1/100 mm, you see, attention and accuracy
                  is what certainly helps), grouping the shaft seal diameter on all shafts in the batch on the
                  lower border of still good dimension.... I remember around extra 400W saved on 100 kW
                  3000 rpm electric motor, all being tested on one, same motor in one day, the shaft diameter
                  was originally machined to the top value diameter of the "previously acceptable" tolerance field,
                  and grinding it again (putting it back on the machine) was removing minimum 2/100 mm
                  and more, to the lower border.

                  So, the difference between a good motor and high efficiency one was a changed tolerance
                  field on the rotor machining drawing and extra ~1 euro for more expensive shaft seals. In your
                  case, it is very little likely that you will reach all your desired progress on one component only,
                  it is more likely that you will get a little on several components and sub assemblies and so it
                  then piles up, I could, for example, reduce these losses even further by reducing the fan size,
                  but it had to be used for some other models. ;o)

                  the method of turning the engine using an electric motor in order to discover and measure the
                  losses of each sub assembly and measure the improvement after modifications has a name
                  in english, I think.

                  there's more to this but here I'll choose to seize
                  my opportunity to wish a nice day to everyone,

                  sascha
                  http://www.jestartech.com
                   
                   
                   
                   
                   
                   
                   
                   
                   

                  Hans Passberger wrote:

                  which other things??

                  Tony Foale wrote:
                  > Unfortunately this doesn't come cheap, but there are other things that
                  > can be done without much cost.

                • Pete Snell
                  Hi All I was just catching up on the digests and was intrigued by this thread. One thing I didn t see mentioned was the possibility that the belt driven
                  Message 8 of 24 , Nov 27, 2007
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                    Hi All

                    I was just catching up on the digests and was intrigued by this thread.
                    One thing I didn't see mentioned was the possibility that the belt
                    driven driveline may have some how increased grip at the rear wheel.
                    Could this be part of the observed effect?

                    Pete

                    --
                    Pete Snell
                    Department of Physics
                    Royal Military College
                    Snell-p@...
                    ---------------------------------------------------------------------
                    In a car everything you see is just more TV. You're a passive observer
                    and it is all moving by you boringly in a frame. On a cycle the frame is
                    completely gone. You're completely in contact with it all. You're in the
                    scene, not just watching it anymore, and the sense of presence is overwhelming.
                    Robert Pirsig
                    Zen and the Art of Motorcycle Maintenance. (1974)
                  • Danny Whitfield
                    ... I am convinced that the absence of heat producing mechanical hinges in ... Dan Whitfield --
                    Message 9 of 24 , Nov 27, 2007
                    • 0 Attachment
                      On 11/27/07, Pete Snell <snell-p@...> wrote:

                      Hi All

                      I was just catching up on the digests and was intrigued by this thread.
                      One thing I didn't see mentioned was the possibility that the belt
                      driven driveline may have some how increased grip at the rear wheel.
                      Could this be part of the observed effect?

                      I don't think so pete, there was no loss of traction as I rolled out of a very slow low gear hairpin curve and accellerated on straight track up through the gears as identically as I could manage in all 200+ vehicles at least 10 laps per bike. The speeds repeated with very few exceptons.


                       

                      I am convinced that the absence of heat producing mechanical hinges in the toothed kevlar belt coupled with lighter belt weight accounts for the difference.

                       
                      Dan Whitfield

                       

                      --
                      Pete Snell
                      Department of Physics
                      Royal Military College
                      Snell-p@...
                      ----------------------------------------------------------
                      In a car everything you see is just more TV. You're a passive observer
                      and it is all moving by you boringly in a frame. On a cycle the frame is
                      completely gone. You're completely in contact with it all. You're in the
                      scene, not just watching it anymore, and the sense of presence is overwhelming.
                      Robert Pirsig
                      Zen and the Art of Motorcycle Maintenance. (1974)


                    • RohanB
                      What about if the gearing was different between chain and belt drive ? Are they IDENTICAL ? Reminds me of the story of how Nortons got the Norton Commando past
                      Message 10 of 24 , Nov 27, 2007
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                        What about if the gearing was different between chain and belt drive ?
                        Are they IDENTICAL ?

                        Reminds me of the story of how Nortons got the Norton Commando past the
                        noise test in the 1970s. Since they didn't have the budget to alter it
                        mechanically to quieten it down in any way, all they did was increase the
                        size of the gearbox sprocket in the final drive a few teeth. When they did
                        the mandatory roll-on test in 2nd gear, the taller gearing limited the
                        acceleration enough to quieten it down enough to (easily) pass the noise
                        test (Was it 86 dBA back then ?). Since the gearing was optional, they
                        didn't even have to sell them like this......

                        Cheers,
                        Rohan.

                        ----------
                        From: Danny Whitfield <eco.usa@...>
                        To: mc-engine@yahoogroups.com
                        Subject: Re: Friction loss
                        Date: Wednesday, November 28, 2007 11:07 AM

                        On 11/27/07, Pete Snell <snell-p@...> wrote:
                        >
                        > Hi All
                        >
                        > I was just catching up on the digests and was intrigued by this thread.
                        > One thing I didn't see mentioned was the possibility that the belt
                        > driven driveline may have some how increased grip at the rear wheel.
                        > Could this be part of the observed effect?
                        >
                        > I don't think so pete, there was no loss of traction as I rolled out of a
                        > very slow low gear hairpin curve and accellerated on straight track up
                        > through the gears as identically as I could manage in all 200+ vehicles
                        at
                        > least 10 laps per bike. The speeds repeated with very few exceptons.
                        >
                        >
                        >
                        I am convinced that the absence of heat producing mechanical hinges in
                        > the toothed kevlar belt coupled with lighter belt weight accounts for the
                        > difference.
                        >

                        Dan Whitfield



                        --
                        > Pete Snell
                        > Department of Physics
                        > Royal Military College
                        > Snell-p@... <Snell-p%40rmc.ca>
                        > ----------------------------------------------------------
                        > In a car everything you see is just more TV. You're a passive observer
                        > and it is all moving by you boringly in a frame. On a cycle the frame is
                        > completely gone. You're completely in contact with it all. You're in the
                        > scene, not just watching it anymore, and the sense of presence is
                        > overwhelming.
                        > Robert Pirsig
                        > Zen and the Art of Motorcycle Maintenance. (1974)
                        >
                        >
                        >
                      • Danny Whitfield
                        ... The driven bike was geared slightly higher than the chain drive bike. This should have made the belt driven bike slower to build power, not faster. But
                        Message 11 of 24 , Nov 27, 2007
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                          On 11/27/07, RohanB <newboltz333@...> wrote:

                          What about if the gearing was different between chain and belt drive ?
                          Are they IDENTICAL ?

                           
                          The driven bike was geared slightly higher than the chain drive bike. This should have made the belt driven bike slower to build power, not faster.  But faster it was!  (Dan Whitfield)

                           

                          Reminds me of the story of how Nortons got the Norton Commando past the
                          noise test in the 1970s. Since they didn't have the budget to alter it
                          mechanically to quieten it down in any way, all they did was increase the
                          size of the gearbox sprocket in the final drive a few teeth. When they did
                          the mandatory roll-on test in 2nd gear, the taller gearing limited the
                          acceleration enough to quieten it down enough to (easily) pass the noise
                          test (Was it 86 dBA back then ?). Since the gearing was optional, they
                          didn't even have to sell them like this......

                          Cheers,
                          Rohan.

                          ----------
                          From: Danny Whitfield < eco.usa@...>
                          To: mc-engine@yahoogroups.com
                          Subject: Re: Friction loss
                          Date: Wednesday, November 28, 2007 11:07 AM

                          On 11/27/07, Pete Snell <snell-p@...> wrote:
                          >
                          > Hi All
                          >
                          > I was just catching up on the digests and was intrigued by this thread.
                          > One thing I didn't see mentioned was the possibility that the belt
                          > driven driveline may have some how increased grip at the rear wheel.
                          > Could this be part of the observed effect?
                          >
                          > I don't think so pete, there was no loss of traction as I rolled out of a
                          > very slow low gear hairpin curve and accellerated on straight track up
                          > through the gears as identically as I could manage in all 200+ vehicles
                          at
                          > least 10 laps per bike. The speeds repeated with very few exceptons.
                          >
                          >
                          >
                          I am convinced that the absence of heat producing mechanical hinges in
                          > the toothed kevlar belt coupled with lighter belt weight accounts for the
                          > difference.
                          >

                          Dan Whitfield

                          --
                          > Pete Snell
                          > Department of Physics
                          > Royal Military College
                          > Snell-p@... <Snell-p%40rmc.ca>
                          > ----------------------------------------------------------
                          > In a car everything you see is just more TV. You're a passive observer
                          > and it is all moving by you boringly in a frame. On a cycle the frame is
                          > completely gone. You're completely in contact with it all. You're in the
                          > scene, not just watching it anymore, and the sense of presence is
                          > overwhelming.
                          > Robert Pirsig
                          > Zen and the Art of Motorcycle Maintenance. (1974)
                          >
                          >
                          >


                        • Ken Augustine
                          Another way was to bend the tachometer needle for AMA noise tests. KA ... From: Danny Whitfield To: mc-engine@yahoogroups.com Sent:
                          Message 12 of 24 , Nov 27, 2007
                          • 0 Attachment
                            Another way was to bend the tachometer needle for AMA noise tests.

                            KA

                            ================================================
                            ----- Original Message ----
                            From: Danny Whitfield <eco.usa@...>
                            To: mc-engine@yahoogroups.com
                            Sent: Tuesday, November 27, 2007 6:48:41 PM
                            Subject: Re: Friction loss



                            On 11/27/07, RohanB <newboltz333@ westnet.com. au> wrote:

                            What about if the gearing was different between chain and belt drive ?
                            Are they IDENTICAL ?

                             
                            The driven bike was geared slightly higher than the chain drive bike. This should have made the belt driven bike slower to build power, not faster.  But faster it was!  (Dan Whitfield)

                             

                            Reminds me of the story of how Nortons got the Norton Commando past the
                            noise test in the 1970s. Since they didn't have the budget to alter it
                            mechanically to quieten it down in any way, all they did was increase the
                            size of the gearbox sprocket in the final drive a few teeth. When they did
                            the mandatory roll-on test in 2nd gear, the taller gearing limited the
                            acceleration enough to quieten it down enough to (easily) pass the noise
                            test (Was it 86 dBA back then ?). Since the gearing was optional, they
                            didn't even have to sell them like this......

                            Cheers,
                            Rohan.

                            ----------
                            From: Danny Whitfield < eco.usa@gmail. com>
                            To: mc-engine@yahoogrou ps.com
                            Subject: Re: Friction loss
                            Date: Wednesday, November 28, 2007 11:07 AM

                            On 11/27/07, Pete Snell <snell-p@rmc. ca> wrote:
                            >
                            > Hi All
                            >
                            > I was just catching up on the digests and was intrigued by this thread.
                            > One thing I didn't see mentioned was the possibility that the belt
                            > driven driveline may have some how increased grip at the rear wheel.
                            > Could this be part of the observed effect?
                            >
                            > I don't think so pete, there was no loss of traction as I rolled out of a
                            > very slow low gear hairpin curve and accellerated on straight track up
                            > through the gears as identically as I could manage in all 200+ vehicles
                            at
                            > least 10 laps per bike. The speeds repeated with very few exceptons.
                            >
                            >
                            >
                            I am convinced that the absence of heat producing mechanical hinges in
                            > the toothed kevlar belt coupled with lighter belt weight accounts for the
                            > difference.
                            >

                            Dan Whitfield

                            --
                            > Pete Snell
                            > Department of Physics
                            > Royal Military College
                            > Snell-p@rmc. ca <Snell-p%40rmc. ca>
                            > ------------ --------- --------- --------- --------- --------- -
                            > In a car everything you see is just more TV. You're a passive observer
                            > and it is all moving by you boringly in a frame. On a cycle the frame is
                            > completely gone. You're completely in contact with it all. You're in the
                            > scene, not just watching it anymore, and the sense of presence is
                            > overwhelming.
                            > Robert Pirsig
                            > Zen and the Art of Motorcycle Maintenance. (1974)
                            >
                            >
                            >



                          • RohanB
                            Not necessarily. If the torque band in a HD Big Twin is stronger lower down, then being geared taller may improve the acceleration in some situations.... The
                            Message 13 of 24 , Nov 27, 2007
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                              Not necessarily.
                              If the torque band in a HD Big Twin is stronger lower down, then being
                              geared taller may improve the acceleration in some situations....

                              The fact that the gearing varied between the two means that all conclusions
                              on the road are comparing apples to oranges. As someone said, doing the
                              SAME engine on a dyno with the 2 different drives fitted is the only way.

                              hth.?

                              ----------
                              >>>
                              From: Danny Whitfield <eco.usa@...>
                              To: mc-engine@yahoogroups.com
                              Subject: Re: Friction loss
                              Date: Wednesday, November 28, 2007 12:48 PM


                              The driven bike was geared slightly higher than the chain drive bike. This
                              should have made the belt driven bike slower to build power, not faster.
                              But faster it was! (Dan Whitfield)

                              ----------
                              >
                              On 11/27/07, RohanB <newboltz333@...> wrote:
                              >
                              > What about if the gearing was different between chain and belt drive ?
                              > Are they IDENTICAL ?
                            • Otto Nikolaus
                              I m sorry but I don t get this. Of course a chain has obvious hinges, but they are well lubricated. A belt has a vastly greater number of invisible hinges or
                              Message 14 of 24 , Nov 28, 2007
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                                I'm sorry but I don't get this. Of course a chain has obvious hinges, but they are well lubricated. A belt has a vastly greater number of invisible "hinges" or it would have no flexibility and be unable to wrap round the toothed wheels. It still has internal friction due to movement of the fibres, and possibly internal viscous drag too.
                                 
                                Can you imagine racers not using belts if they were more efficient? Especially the GP 125s!
                                 
                                Otto
                                 
                                On 28/11/2007, Danny Whitfield <eco.usa@...> wrote:


                                On 11/27/07, Pete Snell <snell-p@... > wrote:

                                Hi All

                                I was just catching up on the digests and was intrigued by this thread.
                                One thing I didn't see mentioned was the possibility that the belt
                                driven driveline may have some how increased grip at the rear wheel.
                                Could this be part of the observed effect?

                                I don't think so pete, there was no loss of traction as I rolled out of a very slow low gear hairpin curve and accellerated on straight track up through the gears as identically as I could manage in all 200+ vehicles at least 10 laps per bike. The speeds repeated with very few exceptons.


                                 

                                I am convinced that the absence of heat producing mechanical hinges in the toothed kevlar belt coupled with lighter belt weight accounts for the difference.

                                 
                                Dan Whitfield
                                 

                                 

                              • bikebreakerbob
                                That seems like a huge difference....surely one of the engineer types here could convert that HP loss to BTU s,and that would be heat absorbed by the
                                Message 15 of 24 , Nov 28, 2007
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                                  That seems like a huge difference....surely one of the engineer
                                  types here could convert that HP loss to BTU's,and that would be
                                  heat absorbed by the chain....would we have a 400 degree chain
                                  here??? --- In mc-
                                  engine@yahoogroups.com, "Otto Nikolaus" <otto.nikolaus@...> wrote:
                                  >
                                  > I'm sorry but I don't get this. Of course a chain has obvious
                                  hinges, but
                                  > they are well lubricated. A belt has a vastly greater number of
                                  invisible
                                  > "hinges" or it would have no flexibility and be unable to wrap
                                  round the
                                  > toothed wheels. It still has internal friction due to movement of
                                  the
                                  > fibres, and possibly internal viscous drag too.
                                  >
                                  > Can you imagine racers not using belts if they were more efficient?
                                  > Especially the GP 125s!
                                  >
                                  > Otto
                                  >
                                  > On 28/11/2007, Danny Whitfield <eco.usa@...> wrote:
                                  >
                                  > >
                                  > >
                                  > > On 11/27/07, Pete Snell <snell-p@...> wrote:
                                  > > >
                                  > > > Hi All
                                  > > >
                                  > > > I was just catching up on the digests and was intrigued by
                                  this thread.
                                  > > > One thing I didn't see mentioned was the possibility that the
                                  belt
                                  > > > driven driveline may have some how increased grip at the rear
                                  wheel.
                                  > > > Could this be part of the observed effect?
                                  > > >
                                  > > > I don't think so pete, there was no loss of traction as I
                                  rolled out of
                                  > > > a very slow low gear hairpin curve and accellerated on
                                  straight track up
                                  > > > through the gears as identically as I could manage in all 200+
                                  vehicles at
                                  > > > least 10 laps per bike. The speeds repeated with very few
                                  exceptons.
                                  > > >
                                  > > >
                                  > > >
                                  > > I am convinced that the absence of heat producing mechanical
                                  hinges in
                                  > > > the toothed kevlar belt coupled with lighter belt weight
                                  accounts for the
                                  > > > difference.
                                  > > >
                                  > >
                                  > > Dan Whitfield
                                  > >
                                  >
                                • Otto Nikolaus
                                  I can t make this add up whichever way I look at it. A speed gain of 87-93 MPH represents a difference of 18%* in power reaching the wheel. This 18% would have
                                  Message 16 of 24 , Nov 28, 2007
                                  • 0 Attachment
                                    I can't make this add up whichever way I look at it. A speed gain of
                                    87-93 MPH represents a difference of 18%* in power reaching the wheel.
                                    This 18% would have to come from the saving over the chain, which
                                    would have to be less than 82% efficient, even if the belt were 100%
                                    (perfectly) efficicient.

                                    Taking a very conservative figure of 30 HP at 100 MPH, 87 MPH requires
                                    20 HP. 18% of this is about 3.5 HP or about 2.6 kW. That would be some
                                    heater cooking the grease/oil in your chain. ;) We can't work out the
                                    actual temp unless we know the cooling available.

                                    *As Tony said, it could be less if the bike had an erratic power curve
                                    in that speed range but we can only guess.

                                    Otto

                                    On 28/11/2007, bikebreakerbob <foist@...> wrote:
                                    > That seems like a huge difference....surely one of the engineer
                                    > types here could convert that HP loss to BTU's,and that would be
                                    > heat absorbed by the chain....would we have a 400 degree chain
                                    > here???
                                  • Ken Augustine
                                    All, Don t forget, this isn t at stabilized top RPM, not just speed where a predictable second order or higher function would be in effect and that, as
                                    Message 17 of 24 , Nov 28, 2007
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                                      All,

                                      Don't forget, this isn't at stabilized top   RPM,   not just speed where a predictable second order or higher function would be in effect and that, as Tony stated, there may be a particularly vulnerable power curve at play.   I remember a pal racing a G-50 because it could pull off corners at ill advisedly low rpm whereas a Manx with an extra hp or two up top, if let drop below some lower bound in the power curve, could get into  *megaphone-itis* and absolutely refuse to accelerate.   If the overall gearing with the belt drive avoided any anomaly in the power curve, the difference could be magnified.  

                                      Beyond that, the temperature of the drive would undoubtedly be as good an indication of the loss although it would be a time dependent function.   This below is a different situation but decades ago I ran my modified street bike on a Matra eddy current, rear tire drive, dyno which had always proven reliable but I couldn't get the bike to pull a single foot pound of torque without instantly sagging the rpm downward.   I kept raising the rpm until it was screaming but it wouldn't sustain the load of the first winding on the fine wire load petentiometer without the rpm falling precipitously.   I checked and rechecked everything with the engine which seemed fine and sounded great so I really leaned on it, nursing the load on and off that first winding in an effort to get the thing to show some evidence of the problem until after about 5 seconds of full throttle, the new Avon rear tire disintegrated.   I then installed an old and hardened Goodyear racing tire through which the bike delivered 67hp on the first pull.  

                                      I realize that the tires on the Harleys haven't been described or defined but the energy has to be going somewhere and the temperature is a good way to look for it but if the overall gearing isn't identical or accounted for, the results are like comparing apples to applets.  

                                      Ken A


                                      ----- Original Message ----
                                      From: Otto Nikolaus <otto.nikolaus@...>
                                      To: mc-engine@yahoogroups.com
                                      Sent: Wednesday, November 28, 2007 4:45:55 AM
                                      Subject: Re: Friction loss

                                      I can't make this add up whichever way I look at it. A speed gain of
                                      87-93 MPH represents a difference of 18%* in power reaching the wheel.
                                      This 18% would have to come from the saving over the chain, which
                                      would have to be less than 82% efficient, even if the belt were 100%
                                      (perfectly) efficicient.

                                      Taking a very conservative figure of 30 HP at 100 MPH, 87 MPH requires
                                      20 HP. 18% of this is about 3.5 HP or about 2.6 kW. That would be some
                                      heater cooking the grease/oil in your chain. ;) We can't work out the
                                      actual temp unless we know the cooling available.

                                      *As Tony said, it could be less if the bike had an erratic power curve
                                      in that speed range but we can only guess.

                                      Otto

                                      On 28/11/2007, bikebreakerbob <foist@hsonline. net> wrote:
                                      > That seems like a huge difference.. ..surely one of the engineer
                                      > types here could convert that HP loss to BTU's,and that would be
                                      > heat absorbed by the chain....would we have a 400 degree chain
                                      > here???


                                    • ray_r.rm
                                      All: Go back a few days to message 13902 where Danny mentions that the overall drive ratio was different for the belt drive than the chain drive. So there no
                                      Message 18 of 24 , Nov 28, 2007
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                                        All:
                                        Go back a few days to message 13902 where Danny mentions that the
                                        overall drive ratio was different for the belt drive than the chain drive.

                                        So there no mystery about friction. It was not a scientific experiment
                                        at all.

                                        -- Rich


                                        --- In mc-engine@yahoogroups.com, "Otto Nikolaus" <otto.nikolaus@...>
                                        wrote:
                                        >
                                        > I can't make this add up whichever way I look at it. A speed gain of
                                        > 87-93 MPH represents a difference of 18%* in power reaching the wheel.
                                        > This 18% would have to come from the saving over the chain, which
                                        > would have to be less than 82% efficient, even if the belt were 100%
                                        > (perfectly) efficicient.
                                        >
                                        > Taking a very conservative figure of 30 HP at 100 MPH, 87 MPH requires
                                        > 20 HP. 18% of this is about 3.5 HP or about 2.6 kW. That would be some
                                        > heater cooking the grease/oil in your chain. ;) We can't work out the
                                        > actual temp unless we know the cooling available.
                                        >
                                        > *As Tony said, it could be less if the bike had an erratic power curve
                                        > in that speed range but we can only guess.
                                        >
                                        > Otto
                                        >
                                        > On 28/11/2007, bikebreakerbob <foist@...> wrote:
                                        > > That seems like a huge difference....surely one of the engineer
                                        > > types here could convert that HP loss to BTU's,and that would be
                                        > > heat absorbed by the chain....would we have a 400 degree chain
                                        > > here???
                                        >
                                      • Otto Nikolaus
                                        The initial claim was that replacing chain with belt produced a speed increase from 87 to 93 MPH. On what basis was this claim made? Otto
                                        Message 19 of 24 , Nov 28, 2007
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                                          The initial claim was that replacing chain with belt produced a speed
                                          increase from 87 to 93 MPH.

                                          On what basis was this claim made?

                                          Otto

                                          On 28/11/2007, ray_r.rm <ray_r@...> wrote:
                                          > All:
                                          > Go back a few days to message 13902 where Danny mentions that the
                                          > overall drive ratio was different for the belt drive than the chain drive.
                                          >
                                          > So there no mystery about friction. It was not a scientific experiment
                                          > at all.
                                        • Danny Whitfield
                                          ... Remember, this is a factory production Harley with stock exhaust not megaphones. It has a torque curve like a locomotive (no flat spots). The tires were
                                          Message 20 of 24 , Nov 28, 2007
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                                            On 11/28/07, Ken Augustine <kineticanalysis@...> wrote:

                                            All,

                                            Don't forget, this isn't at stabilized top   RPM,   not just speed where a predictable second order or higher function would be in effect and that, as Tony stated, there may be a particularly vulnerable power curve at play.   I remember a pal racing a G-50 because it could pull off corners at ill advisedly low rpm whereas a Manx with an extra hp or two up top, if let drop below some lower bound in the power curve, could get into  *megaphone-itis* and absolutely refuse to accelerate.   If the overall gearing with the belt drive avoided any anomaly in the power curve, the difference could be magnified.  
                                             
                                            Remember, this is a factory production Harley with stock exhaust not megaphones. It has a torque curve like a locomotive (no flat spots).  The tires were identical Dunlops and everything was identical except the primary and secondary drives.
                                             
                                            I would bet that where ever in the world you are, examples of these two bikes are also, and could be put side by side again and run with similar results. 
                                             
                                            Danny Whitfield

                                             

                                            Beyond that, the temperature of the drive would undoubtedly be as good an indication of the loss although it would be a time dependent function.   This below is a different situation but decades ago I ran my modified street bike on a Matra eddy current, rear tire drive, dyno which had always proven reliable but I couldn't get the bike to pull a single foot pound of torque without instantly sagging the rpm downward.   I kept raising the rpm until it was screaming but it wouldn't sustain the load of the first winding on the fine wire load petentiometer without the rpm falling precipitously.   I checked and rechecked everything with the engine which seemed fine and sounded great so I really leaned on it, nursing the load on and off that first winding in an effort to get the thing to show some evidence of the problem until after about 5 seconds of full throttle, the new Avon rear tire disintegrated.   I then installed an old and hardened Goodyear racing tire through which the bike delivered 67hp on the first pull.  

                                            I realize that the tires on the Harleys haven't been described or defined but the energy has to be going somewhere and the temperature is a good way to look for it but if the overall gearing isn't identical or accounted for, the results are like comparing apples to applets.  

                                            Ken A


                                            ----- Original Message ----
                                            From: Otto Nikolaus < otto.nikolaus@...>
                                            To: mc-engine@yahoogroups.com
                                            Sent: Wednesday, November 28, 2007 4:45:55 AM
                                            Subject: Re: Friction loss

                                            I can't make this add up whichever way I look at it. A speed gain of
                                            87-93 MPH represents a difference of 18%* in power reaching the wheel.
                                            This 18% would have to come from the saving over the chain, which
                                            would have to be less than 82% efficient, even if the belt were 100%
                                            (perfectly) efficicient.

                                            Taking a very conservative figure of 30 HP at 100 MPH, 87 MPH requires
                                            20 HP. 18% of this is about 3.5 HP or about 2.6 kW. That would be some
                                            heater cooking the grease/oil in your chain. ;) We can't work out the
                                            actual temp unless we know the cooling available.

                                            *As Tony said, it could be less if the bike had an erratic power curve
                                            in that speed range but we can only guess.

                                            Otto

                                            On 28/11/2007, bikebreakerbob < foist@hsonline. net> wrote:
                                            > That seems like a huge difference.. ..surely one of the engineer
                                            > types here could convert that HP loss to BTU's,and that would be
                                            > heat absorbed by the chain....would we have a 400 degree chain
                                            > here???


                                             


                                          • Dan Timberlake
                                            http://www.latus-harley-davidson.com/mbbs2/forums/thread-view.asp? tid=106&mid=444#M444 http://www.latus-harley-davidson.com/mbbs2/forums/thread-view.asp?
                                            Message 21 of 24 , Nov 28, 2007
                                            • 0 Attachment
                                              http://www.latus-harley-davidson.com/mbbs2/forums/thread-view.asp?
                                              tid=106&mid=444#M444

                                              http://www.latus-harley-davidson.com/mbbs2/forums/thread-view.asp?
                                              tid=106&mid=452#M452



                                              --- In mc-engine@yahoogroups.com, "Danny Whitfield" <eco.usa@...>
                                              wrote:
                                              >
                                              >
                                              > Remember, this is a factory production Harley with stock exhaust
                                              not
                                              > megaphones. It has a torque curve like a locomotive (no flat
                                              spots). The tires were identical Dunlops and everything was
                                              identical except the primary and secondary drives.
                                              >
                                              > I would bet that where ever in the world you are, examples of
                                              these two > bikes are also, and could be put side by side again and
                                              run with similar results.
                                              >
                                              > Danny Whitfield
                                              >
                                              >
                                              >
                                              >
                                            • Danny Whitfield
                                              ... I wonder if Latus Harley-Davidson would be willing to dyno a bike before and after changing from chain to belt drive primary and secondary and publish the
                                              Message 22 of 24 , Nov 28, 2007
                                              • 0 Attachment
                                                On 11/28/07, Dan Timberlake <djtcz@...> wrote:
                                                 
                                                I wonder if Latus Harley-Davidson would be willing to dyno a bike before and after changing from chain to belt drive primary and secondary and publish the overlaid dyno graphs? Would this not settle the question?

                                                 

                                                --- In mc-engine@yahoogroups.com, "Danny Whitfield" <eco.usa@...>
                                                wrote:
                                                >
                                                >
                                                > Remember, this is a factory production Harley with stock exhaust
                                                not
                                                > megaphones. It has a torque curve like a locomotive (no flat
                                                spots). The tires were identical Dunlops and everything was
                                                identical except the primary and secondary drives.
                                                >
                                                > I would bet that where ever in the world you are, examples of
                                                these two > bikes are also, and could be put side by side again and
                                                run with similar results.
                                                >
                                                > Danny Whitfield
                                                >
                                                >
                                                >
                                                >


                                              • Hans Passberger
                                                two questions, as I´m doing my heads (aircooled, Heron-style): Is there any perfect valve shape for best performance? tulip, flat, any other? Any concerns
                                                Message 23 of 24 , Nov 29, 2007
                                                • 0 Attachment
                                                  two questions, as I´m doing my heads (aircooled, Heron-style):
                                                  Is there any "perfect" valve shape for best performance?
                                                  tulip, flat, any other?

                                                  Any concerns about installing overlapping valve seats?
                                                  Otherway no room for bigger valves.
                                                • djtcz@comcast.net
                                                  I m eager to hear what Ken says, but I ve noticed that generally the back of the valve needs to match the port approach. Flat valves may be best in engines
                                                  Message 24 of 24 , Nov 30, 2007
                                                  • 0 Attachment
                                                    I'm eager to hear what Ken says, but I've noticed that generally the back of the valve needs to match the port approach. 
                                                     
                                                    Flat valves may be "best" in engines whose ports have a tight floor radius and are more nearly 90 degrees to the stem centerline.  http://www.aa1car.com/library/cylinder_head1.jpg
                                                    Of course there wil be exceptions
                                                     
                                                    Tuliped valves belong with ports that are more nearly parallel with the valve stem
                                                     
                                                     
                                                     
                                                    --
                                                    Dan Timberlake
                                                     
                                                    -------------- Original message --------------
                                                    From: Hans Passberger <passberger@...>

                                                    two questions, as I�m doing my heads (aircooled, Heron-style) :
                                                    Is there any "perfect" valve shape for best performance?
                                                    tulip, flat, any other?

                                                    Any concerns about installing overlapping valve seats?
                                                    Otherway no room for bigger valves.

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