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Re: [Small4-strokeEngines] Sweet Briggs V-twin

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  • Scott Perkins
    It would be much better to talk to actual users of the engines instead of the builders sellers for factual data.... plus, please do not mention airplane use to
    Message 1 of 17 , Sep 1, 2004
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      It would be much better to talk to actual users of the engines instead
      of the builders sellers for factual data.... plus, please do not
      mention airplane use to anyone you speak to. Currently these
      engines are available without cross checking of racing kart
      chassis number or race kart association membership info
      but last year they almost implememted that amid scares
      and rumors of non-appropriate use.

      They basically are taking the next to largest size motors
      and replacing pistons, removing govenor, altering carbs and
      cams. They then seal the engines for "formula" use on the
      racetrack whereby no one is allowed to tinker inside the
      engine further... They run them for 40 races per season at
      rpms up to 5,000 in the Bandolero and 600 series...

      Find your closest race track and go see em in action
      and talk to the owners etc. Currently they do not offer
      souped up "largest versions" as the biggest Briggs motor
      did not exist at the time of the development of hte
      race kart engine. There is such a population of the motors
      that it was decided to stick with the same "next to largest"
      motor for continuity ... plus they do not have the forged
      pistons in the larger size necessary to modify the larger
      engine. apparently the stock cast piston has been found
      not to hold up to 40 races at 5,000 rpms and normal gas.
      I contacted Mahle where they get the pistons and minimum
      order was for 25 custom pistons. User/racers estimate
      32 hp at max revs of 5,000 during racing from the normally
      quoted as 20 hp stock engine...
      Scott

      Jeff wrote:
      >
      > here is a link to company in North Carolina the is Building Briggs
      > Vanguard engines. http://www.perkart.com/vtwin.htm I am going to
      > give them a call and see for sure what kind of #'s these engines are
      > putting out. I am here in Illinois and am currently building a
      > afforaplane and really want a 4-stroke engine, 35-50hp, and under
      > 80lbs. I want to put alittle bit more effort in building my
      > powerplant just to be differant and in my mind on the leading edge
      > of power plants for ultralights.
      >
      > I Was looking in the photo section of this group and saw the
      > ReDrive and pullys for the briggs v-twin... I am wondering where I
      > can get them for my project.
      >
      > So far this group has been alot of help of keeping my ideas alive
      > for a 4-stroke ultralight that will someday compete with the 2-
      > stroke ultralight.
      >
      > Jeff Vernier
      >
      >
      > ### Lets use this list to build a knowledge base for those who are
      > interested in flying with these engines. Don't forget you can search the
      > messages archive for past discussions. Please keep comments on subject.
      > Sorry, no attachments allowed.
      >
      > For access to the home page:
      > >http://groups.yahoo.com/group/Small4-strokeEngines/<
      >
      > For direct access to the files area:
      > >http://groups.yahoo.com/group/Small4-strokeEngines/files/<
      > Yahoo! Groups Links
      >
      >
      >
      >
    • gyachts
      I looked at the V-Twin s before and they only produced 18hp, I m pretty sure. I don t remember the weight but it wasn t very good HP/LBs. Greg
      Message 2 of 17 , Sep 1, 2004
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        I looked at the V-Twin's before and they only produced 18hp, I'm
        pretty sure.

        I don't remember the weight but it wasn't very good HP/LBs.

        Greg
      • Jeff
        that is true, from the factory that is the HP rating, but after doing a few simple modifications like making it breathe better (k&N filter, open exhaust,
        Message 3 of 17 , Sep 2, 2004
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          that is true, from the factory that is the HP rating, but after
          doing a few simple modifications like making it breathe better (k&N
          filter, open exhaust, richen fuel mixture up, advance the timing,
          you can almost double the hp of these v-twins. Now if you raise the
          compression ratio, install forged pistons and cams your in the high
          40's. Now put stiffer valve springs in it, roller rockers. and port
          the head you are over 50hp, you could also put bigger valves in it
          and get a bit more but that takes a bit of machining. I think the
          weight is somewhere around 80lbs but im going to do some more
          checking today

          jeff

          --- In Small4-strokeEngines@yahoogroups.com, "gyachts"
          <gyachts@y...> wrote:
          > I looked at the V-Twin's before and they only produced 18hp, I'm
          > pretty sure.
          >
          > I don't remember the weight but it wasn't very good HP/LBs.
          >
          > Greg
        • Chris Viningre
          I have studied doing the same thing with a Kawasaki V-Twin engine. You may want to consider a different connecting rod sense the stock one is aluminum. Also
          Message 4 of 17 , Sep 2, 2004
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            I have studied doing the same thing with a Kawasaki V-Twin engine. You may want to consider a different connecting rod sense the stock one is aluminum. Also look at beefing up the crankcase and machining it for ball or roller bearings. Plain bearings don't handle side thrust very well. Head gasket should be changed to a copper gasket to handle the compression. All of this will increase the BTU of the engine so consider a oil cooler and a extra quirt of oil. Check the guys that are doing tractor pulls with these engines. They have come up with some neat parts. Good luck.

            Chris
            ----- Original Message -----
            From: Jeff
            To: Small4-strokeEngines@yahoogroups.com
            Sent: Thursday, September 02, 2004 8:25 AM
            Subject: [Small4-strokeEngines] Re: Sweet Briggs V-twin


            that is true, from the factory that is the HP rating, but after
            doing a few simple modifications like making it breathe better (k&N
            filter, open exhaust, richen fuel mixture up, advance the timing,
            you can almost double the hp of these v-twins. Now if you raise the
            compression ratio, install forged pistons and cams your in the high
            40's. Now put stiffer valve springs in it, roller rockers. and port
            the head you are over 50hp, you could also put bigger valves in it
            and get a bit more but that takes a bit of machining. I think the
            weight is somewhere around 80lbs but im going to do some more
            checking today

            jeff

            --- In Small4-strokeEngines@yahoogroups.com, "gyachts"
            <gyachts@y...> wrote:
            > I looked at the V-Twin's before and they only produced 18hp, I'm
            > pretty sure.
            >
            > I don't remember the weight but it wasn't very good HP/LBs.
            >
            > Greg




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          • tmservice1096@sbcglobal.net
            Jeff, where do you get the forged pistons, steel rod, stiffer valve springs, roller rockers, ect? Tom ... From: Jeff To:
            Message 5 of 17 , Sep 3, 2004
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              Jeff, where do you get the forged pistons, steel rod, stiffer valve springs,
              roller rockers, ect? Tom
              ----- Original Message -----
              From: "Jeff" <kenwoodjeff@...>
              To: <Small4-strokeEngines@yahoogroups.com>
              Sent: Thursday, September 02, 2004 10:25 AM
              Subject: [Small4-strokeEngines] Re: Sweet Briggs V-twin


              > that is true, from the factory that is the HP rating, but after
              > doing a few simple modifications like making it breathe better (k&N
              > filter, open exhaust, richen fuel mixture up, advance the timing,
              > you can almost double the hp of these v-twins. Now if you raise the
              > compression ratio, install forged pistons and cams your in the high
              > 40's. Now put stiffer valve springs in it, roller rockers. and port
              > the head you are over 50hp, you could also put bigger valves in it
              > and get a bit more but that takes a bit of machining. I think the
              > weight is somewhere around 80lbs but im going to do some more
              > checking today
              >
              > jeff
              >
              > --- In Small4-strokeEngines@yahoogroups.com, "gyachts"
              > <gyachts@y...> wrote:
              > > I looked at the V-Twin's before and they only produced 18hp, I'm
              > > pretty sure.
              > >
              > > I don't remember the weight but it wasn't very good HP/LBs.
              > >
              > > Greg
              >
              >
              >
              >
              >
              > ### Lets use this list to build a knowledge base for those who are
              > interested in flying with these engines. Don't forget you can search the
              > messages archive for past discussions. Please keep comments on subject.
              > Sorry, no attachments allowed.
              >
              > For access to the home page:
              > >http://groups.yahoo.com/group/Small4-strokeEngines/<
              >
              > For direct access to the files area:
              > >http://groups.yahoo.com/group/Small4-strokeEngines/files/<
              > Yahoo! Groups Links
              >
              >
              >
              >
              >
              >
            • Kev Armstrong
              Jeff wrote ... * The really frustrating thing is that the giants such as Honda, Kawasaki, etc etc could produce the definitive four-stroke for ultralight use,
              Message 6 of 17 , Sep 5, 2004
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                Jeff wrote
                > So far this group has been alot of help of keeping my ideas alive
                > for a 4-stroke ultralight that will someday compete with the 2-
                > stroke ultralight.
                >
                > Jeff Vernier

                * The really frustrating thing is that the giants such as Honda,
                Kawasaki, etc etc could produce the definitive four-stroke for
                ultralight use, as a minor project; good people like you Guys are
                having to sneak around trying to see what can be achieved.

                I suspect that the legal eagles have been so good at getting a nice
                fat pay out from companies making such products, that we may struggle
                to keep a secure supply, even if one of them was brave enough to 'do
                a Rotax' and produce such a unit. Sooner or later someone might
                succeed in blaming his pilot error on his power-unit, and the
                production line would soon shut down.

                Ironically the enviro-movement might in the end benefit us, personal
                watercraft are right in our weight/horsepower range and are getting
                leant on hard to go four stroke, and European scooters, recently more
                or less forced to go 4-cycle, are having a bit of a horsepower race
                in the larger capacities.

                So eventually, and unintentionally, some outfit somewhere will build
                such a unit and see sales suddenly blossom, hopefully when they
                discover it is aircraft builders tearing the power unit out to bolt
                into their Ultralights they won't stop making them.

                I've been watching the Scooter market with interest, as they tend to
                come with centrifugal clutches, and a built-in belt redrive. Although
                not appropriate to raise on here, Aprilia now fit a direct-in-head
                injection system to their scooters (called Ditech on their website)
                which gets rid of many of the flaws in two-stroke motors. This is
                similar to the Mitsubishi GDI system.

                Another irony is that this week I'm picking up an SV650 vee twin
                Suzuki, to use to get to the airfield. 70+ horspower and the entire
                bike only weighs 360 pounds, by the time you've chopped off all the
                bike parts, and maybe the electric start unit the core engine will be
                very light.

                It might be economic to actually buy a full product and remove the
                engine, because of the inflated price we pay for the aircraft
                intended article. A search on the net meant I could buy the full bike
                for £3,800 British pounds. A similar power Rotax engine is at least
                twice that, and you may also give a wry smile at the fact that the
                Big Aprilia Vee twin motorcycles use a superb Rotax made unit....

                Kevin Armstrong
                (no relation to Neil)
              • JERRY
                Jeff wrote: that is true, from the factory that is the HP rating, but after doing a few simple modifications like making it breathe better (k&N filter, open
                Message 7 of 17 , Sep 7, 2004
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                  Jeff wrote:

                  "that is true, from the factory that is the HP rating, but after
                  doing a few simple modifications like making it breathe better (k&N
                  filter, open exhaust, richen fuel mixture up, advance the timing,
                  you can almost double the hp of these v-twins. Now if you raise the
                  compression ratio, install forged pistons and cams your in the high
                  40's. Now put stiffer valve springs in it, roller rockers. and port
                  the head you are over 50hp, you could also put bigger valves in it
                  and get a bit more but that takes a bit of machining. I think the
                  weight is somewhere around 80lbs but im going to do some more
                  checking today"

                  Jerry writes:

                  These modifications for power increases are probably rather optimistic.
                  Improved breathing might provide a few per cent improvement in torque, but
                  the only way to get substantial horse power increases with these small
                  engines is to increase rpm, which is what these modifications do.

                  But higher rpm means more friction, more wear with much shorter life, more
                  excess heat to get rid of (hard to do in an air-cooled engine), certainly a
                  need for a reduction drive. And who knows if the crankshaft, case and
                  bearings can take it for very long. All in all, it would be something I
                  would not want to fly with. What we really need for flying is an engine
                  more suitable for a farm tractor, not for a race car.

                  To me the best approach is to go with an aircraft design that works with a
                  stock engine, rather than to try to hot rod an engine to fit an aircraft.
                  Since we only have about 20 to 30 horse power available from stock small
                  industrial engines, we need a very low flying weight to use them. This
                  means low aircraft weight, as well as low pilot weight. If you just want to
                  putt around the patch at 35 to 40 mph, which is about all you will get out
                  of a conventional high drag design, you will need a lot of wing area. If
                  you want to fly at practical cross country speeds, it has to be very low
                  drag, something like a motor glider.

                  I've been crow hopping my BT project plane again, using a 27 hp Rotax 277,
                  and it looks good so far. The BT is a low drag, light weight, one-off
                  design, close to being a motor glider. It should do real well with
                  something like the stock, stripped down, 31 hp direct drive Briggs.

                  Regards,
                  Jerry Booker
                • jeremy_harris_uk
                  I m not so sure that you need to rev these engines much more than stock to still get a decent power output. I used to race a Mini Cooper S here in the UK many
                  Message 8 of 17 , Sep 9, 2004
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                    I'm not so sure that you need to rev these engines much more than
                    stock to still get a decent power output. I used to race a Mini
                    Cooper S here in the UK many years ago, and even with a cleaned up 5
                    port head (siamesed inlet ports on both cylinder and two of the
                    exhausts siamesed in the head) and single 45 DCOE Weber carb it was
                    fairly straightforward to get 100bhp per litre from an engine that
                    revved to around 7000rpm. This was essentially a 1950's engine
                    design, so wasn't at all "high tech". With this as a baseline it
                    should be possible to get 50hp per litre from an engine that only
                    revs to 3500rpm, as the relationship between power and rpm is
                    linear.

                    The B&S is 670cc IIRC, which means that with some attention to
                    improving breathing (cleaning up the ports, perhaps fitting bigger
                    valves, maybe increasing valve lift), making the exhaust system more
                    efficient, perhaps raising the compression ratio slightly and giving
                    it a decent carburation or fuel injection system you should be able
                    to get around 34hp at the stock 3600rpm without too much trouble. I
                    doubt this would stress the engine at all, as they are designed for
                    industrial abuse so will have a healthy reserve cooling margin.
                    Engine reliability should be virtually unnaffected, as most of the
                    loads will be very similar to those of the stock engine (critical
                    loads on cranks, rods etc come largely from rpm, rather than power
                    output).

                    A modest increase in rpm, say to around 4200 or so, may well get you
                    comfortably into the 40hp region without over-stressing things too
                    much. As the "average" microlight/ultralight only needs around 20hp
                    (single seat) 30hp (twin seat) to cruise and as that's where the
                    engines will operate most of the time, reliability shouldn't be any
                    worse than the same engine driving a generator at full load, day in,
                    day out, in the middle of the desert.

                    All in I can see no good reason why any of these V twins shouldn't
                    be good enough for ultralight/microlight use with a bit of work.
                    The larger ones, like the Kohler at 725cc, might be a better bet,
                    simply as "there ain't no substitute for cubic inches" at the end of
                    the day.
                  • Dan Grunloh
                    ... Thanks Jeremy. I think your summary is about right. A number of folks have shown the V-twins can produce up to 40HP, at least long enough for takeoff. I m
                    Message 9 of 17 , Sep 9, 2004
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                      --- In Small4-strokeEngines@yahoogroups.com, "jeremy_harris_uk"
                      <jeremy.s.harris@n...> wrote:

                      > All in I can see no good reason why any of these V twins shouldn't
                      > be good enough for ultralight/microlight use with a bit of work.
                      > The larger ones, like the Kohler at 725cc, might be a better bet,
                      > simply as "there ain't no substitute for cubic inches" at the end
                      > of the day.

                      Thanks Jeremy. I think your summary is about right.
                      A number of folks have shown the V-twins can produce
                      up to 40HP, at least long enough for takeoff.

                      I'm studying the possibility of putting one on my
                      Air Creation Racer trike. The real question for
                      me will be how much power do I really need for
                      continuous high speed operation? My trike is
                      a little havy compared to a Chaser and I don't
                      know if I would be satisfied with 33-35Hp
                      sustained output. I have a Rotax 447 now
                      and do not run it at sustained full throttle
                      as the CHT tends to climb. Max power output in
                      a speed run is probably about 37Hp with the 447.

                      I eventually need a 4-stroke for the limited
                      fuel tasks in competition.

                      --Dan
                    • Chuck Riley
                      I see B & S has come out with a 31 HP engine. I don t have any printed details as yet. Chuck ... From: jeremy_harris_uk To:
                      Message 10 of 17 , Sep 9, 2004
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                        I see B & S has come out with a 31 HP engine. I don't have any printed
                        details as yet.
                        Chuck
                        ----- Original Message -----
                        From: "jeremy_harris_uk" <jeremy.s.harris@...>
                        To: <Small4-strokeEngines@yahoogroups.com>
                        Sent: Thursday, September 09, 2004 2:05 AM
                        Subject: [Small4-strokeEngines] Re: Sweet Briggs V-twin


                        > I'm not so sure that you need to rev these engines much more than
                        > stock to still get a decent power output. I used to race a Mini
                        > Cooper S here in the UK many years ago, and even with a cleaned up 5
                        > port head (siamesed inlet ports on both cylinder and two of the
                        > exhausts siamesed in the head) and single 45 DCOE Weber carb it was
                        > fairly straightforward to get 100bhp per litre from an engine that
                        > revved to around 7000rpm. This was essentially a 1950's engine
                        > design, so wasn't at all "high tech". With this as a baseline it
                        > should be possible to get 50hp per litre from an engine that only
                        > revs to 3500rpm, as the relationship between power and rpm is
                        > linear.
                        >
                        > The B&S is 670cc IIRC, which means that with some attention to
                        > improving breathing (cleaning up the ports, perhaps fitting bigger
                        > valves, maybe increasing valve lift), making the exhaust system more
                        > efficient, perhaps raising the compression ratio slightly and giving
                        > it a decent carburation or fuel injection system you should be able
                        > to get around 34hp at the stock 3600rpm without too much trouble. I
                        > doubt this would stress the engine at all, as they are designed for
                        > industrial abuse so will have a healthy reserve cooling margin.
                        > Engine reliability should be virtually unnaffected, as most of the
                        > loads will be very similar to those of the stock engine (critical
                        > loads on cranks, rods etc come largely from rpm, rather than power
                        > output).
                        >
                        > A modest increase in rpm, say to around 4200 or so, may well get you
                        > comfortably into the 40hp region without over-stressing things too
                        > much. As the "average" microlight/ultralight only needs around 20hp
                        > (single seat) 30hp (twin seat) to cruise and as that's where the
                        > engines will operate most of the time, reliability shouldn't be any
                        > worse than the same engine driving a generator at full load, day in,
                        > day out, in the middle of the desert.
                        >
                        > All in I can see no good reason why any of these V twins shouldn't
                        > be good enough for ultralight/microlight use with a bit of work.
                        > The larger ones, like the Kohler at 725cc, might be a better bet,
                        > simply as "there ain't no substitute for cubic inches" at the end of
                        > the day.
                        >
                        >
                        >
                        >
                        >
                        > ### Lets use this list to build a knowledge base for those who are
                        > interested in flying with these engines. Don't forget you can search the
                        > messages archive for past discussions. Please keep comments on subject.
                        > Sorry, no attachments allowed.
                        >
                        > For access to the home page:
                        > >http://groups.yahoo.com/group/Small4-strokeEngines/<
                        >
                        > For direct access to the files area:
                        > >http://groups.yahoo.com/group/Small4-strokeEngines/files/<
                        > Yahoo! Groups Links
                        >
                        >
                        >
                        >
                        >
                      • cara@edmc.net
                        The way to get the best performance is to tailor a reduction system using belts or cog belts and use the largest diameter prop you can. Tip velocity can be
                        Message 11 of 17 , Sep 9, 2004
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                          The way to get the best performance is to tailor a reduction system using
                          belts or cog belts and use the largest diameter prop you can. Tip velocity
                          can be anywhere between 550 and 650 ft per second.
                          A larger prop diameter will give you added thrust for take-off and climb
                          without any sacrifice in top speed if the prop is pitched right.
                          Graham

                          Dan Grunloh wrote:

                          > --- In Small4-strokeEngines@yahoogroups.com, "jeremy_harris_uk"
                          > <jeremy.s.harris@n...> wrote:
                          >
                          > > All in I can see no good reason why any of these V twins shouldn't
                          > > be good enough for ultralight/microlight use with a bit of work.
                          > > The larger ones, like the Kohler at 725cc, might be a better bet,
                          > > simply as "there ain't no substitute for cubic inches" at the end
                          > > of the day.
                          >
                          > Thanks Jeremy. I think your summary is about right.
                          > A number of folks have shown the V-twins can produce
                          > up to 40HP, at least long enough for takeoff.
                          >
                          > I'm studying the possibility of putting one on my
                          > Air Creation Racer trike. The real question for
                          > me will be how much power do I really need for
                          > continuous high speed operation? My trike is
                          > a little havy compared to a Chaser and I don't
                          > know if I would be satisfied with 33-35Hp
                          > sustained output. I have a Rotax 447 now
                          > and do not run it at sustained full throttle
                          > as the CHT tends to climb. Max power output in
                          > a speed run is probably about 37Hp with the 447.
                          >
                          > I eventually need a 4-stroke for the limited
                          > fuel tasks in competition.
                          >
                          > --Dan
                          >
                          >
                          > ### Lets use this list to build a knowledge base for those who are
                          > interested in flying with these engines. Don't forget you can search the
                          > messages archive for past discussions. Please keep comments on subject.
                          > Sorry, no attachments allowed.
                          >
                          > For access to the home page:
                          > >http://groups.yahoo.com/group/Small4-strokeEngines/<
                          >
                          > For direct access to the files area:
                          > >http://groups.yahoo.com/group/Small4-strokeEngines/files/<
                          > Yahoo! Groups Links
                          >
                          >
                          >
                          >
                        • Dan Grunloh
                          ... using ... velocity ... climb ... Thanks I agree. I have seen some long props in use on competition trikes. I have accepted that the reduction drive and
                          Message 12 of 17 , Sep 10, 2004
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                            --- In Small4-strokeEngines@yahoogroups.com, cara@e... wrote:
                            > The way to get the best performance is to tailor a reduction system
                            using
                            > belts or cog belts and use the largest diameter prop you can. Tip
                            velocity
                            > can be anywhere between 550 and 650 ft per second.
                            > A larger prop diameter will give you added thrust for take-off and
                            climb
                            > without any sacrifice in top speed if the prop is pitched right.
                            > Graham

                            Thanks I agree. I have seen some long props in use on
                            competition trikes. I have accepted that the reduction
                            drive and prop are critical to get the best performance.

                            What do you think of the latest 40HP 1/2VW engine from
                            Scott Casler? They swing a 60 inch prop at 3600 rpm.

                            My current Rotax 447 spins that size prop at 2500rpm
                            at full throttle.

                            --Dan Grunloh



                            >
                            > Dan Grunloh wrote:
                            >
                            > > --- In Small4-strokeEngines@yahoogroups.com, "jeremy_harris_uk"
                            > > <jeremy.s.harris@n...> wrote:
                            > >
                            > > > All in I can see no good reason why any of these V twins
                            shouldn't
                            > > > be good enough for ultralight/microlight use with a bit of work.
                            > > > The larger ones, like the Kohler at 725cc, might be a better
                            bet,
                            > > > simply as "there ain't no substitute for cubic inches" at the
                            end
                            > > > of the day.
                            > >
                            > > Thanks Jeremy. I think your summary is about right.
                            > > A number of folks have shown the V-twins can produce
                            > > up to 40HP, at least long enough for takeoff.
                            > >
                            > > I'm studying the possibility of putting one on my
                            > > Air Creation Racer trike. The real question for
                            > > me will be how much power do I really need for
                            > > continuous high speed operation? My trike is
                            > > a little havy compared to a Chaser and I don't
                            > > know if I would be satisfied with 33-35Hp
                            > > sustained output. I have a Rotax 447 now
                            > > and do not run it at sustained full throttle
                            > > as the CHT tends to climb. Max power output in
                            > > a speed run is probably about 37Hp with the 447.
                            > >
                            > > I eventually need a 4-stroke for the limited
                            > > fuel tasks in competition.
                            > >
                            > > --Dan
                            > >
                            > >
                            > > ### Lets use this list to build a knowledge base for those who are
                            > > interested in flying with these engines. Don't forget you can
                            search the
                            > > messages archive for past discussions. Please keep comments on
                            subject.
                            > > Sorry, no attachments allowed.
                            > >
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                            > >
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                            > > Yahoo! Groups Links
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                          • GeorgeW
                            Dan-- what s the pitch on that 60 prop that scott is using on that 1/2 VW?? GeorgeW ... From: Dan Grunloh To: Small4-strokeEngines@yahoogroups.com Sent:
                            Message 13 of 17 , Sep 10, 2004
                            • 0 Attachment
                              Dan-- what's the pitch on that 60" prop that scott is using on that 1/2 VW??

                              GeorgeW
                              ----- Original Message -----
                              From: Dan Grunloh
                              To: Small4-strokeEngines@yahoogroups.com
                              Sent: Friday, September 10, 2004 10:56 AM
                              Subject: [Small4-strokeEngines] Re: Sweet Briggs V-twin


                              --- In Small4-strokeEngines@yahoogroups.com, cara@e... wrote:
                              > The way to get the best performance is to tailor a reduction system
                              using
                              > belts or cog belts and use the largest diameter prop you can. Tip
                              velocity
                              > can be anywhere between 550 and 650 ft per second.
                              > A larger prop diameter will give you added thrust for take-off and
                              climb
                              > without any sacrifice in top speed if the prop is pitched right.
                              > Graham

                              Thanks I agree. I have seen some long props in use on
                              competition trikes. I have accepted that the reduction
                              drive and prop are critical to get the best performance.

                              What do you think of the latest 40HP 1/2VW engine from
                              Scott Casler? They swing a 60 inch prop at 3600 rpm.

                              My current Rotax 447 spins that size prop at 2500rpm
                              at full throttle.

                              --Dan Grunloh



                              >
                              > Dan Grunloh wrote:
                              >
                              > > --- In Small4-strokeEngines@yahoogroups.com, "jeremy_harris_uk"
                              > > <jeremy.s.harris@n...> wrote:
                              > >
                              > > > All in I can see no good reason why any of these V twins
                              shouldn't
                              > > > be good enough for ultralight/microlight use with a bit of work.
                              > > > The larger ones, like the Kohler at 725cc, might be a better
                              bet,
                              > > > simply as "there ain't no substitute for cubic inches" at the
                              end
                              > > > of the day.
                              > >
                              > > Thanks Jeremy. I think your summary is about right.
                              > > A number of folks have shown the V-twins can produce
                              > > up to 40HP, at least long enough for takeoff.
                              > >
                              > > I'm studying the possibility of putting one on my
                              > > Air Creation Racer trike. The real question for
                              > > me will be how much power do I really need for
                              > > continuous high speed operation? My trike is
                              > > a little havy compared to a Chaser and I don't
                              > > know if I would be satisfied with 33-35Hp
                              > > sustained output. I have a Rotax 447 now
                              > > and do not run it at sustained full throttle
                              > > as the CHT tends to climb. Max power output in
                              > > a speed run is probably about 37Hp with the 447.
                              > >
                              > > I eventually need a 4-stroke for the limited
                              > > fuel tasks in competition.
                              > >
                              > > --Dan
                              > >
                              > >
                              > > ### Lets use this list to build a knowledge base for those who are
                              > > interested in flying with these engines. Don't forget you can
                              search the
                              > > messages archive for past discussions. Please keep comments on
                              subject.
                              > > Sorry, no attachments allowed.
                              > >
                              > > For access to the home page:
                              > > >http://groups.yahoo.com/group/Small4-strokeEngines/<
                              > >
                              > > For direct access to the files area:
                              > > >http://groups.yahoo.com/group/Small4-strokeEngines/files/<
                              > > Yahoo! Groups Links
                              > >
                              > >
                              > >
                              > >




                              ### Lets use this list to build a knowledge base for those who are
                              interested in flying with these engines. Don't forget you can search the
                              messages archive for past discussions. Please keep comments on subject.
                              Sorry, no attachments allowed.

                              For access to the home page:
                              >http://groups.yahoo.com/group/Small4-strokeEngines/<

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                              [Non-text portions of this message have been removed]
                            • Dan Grunloh
                              ... 1/2 VW?? I can t tell you. There is a Yahoo group for 1/2 VW with lots of posters including Scott. I believe the Ultracruiser and a Prowler trike have
                              Message 14 of 17 , Sep 11, 2004
                              • 0 Attachment
                                --- In Small4-strokeEngines@yahoogroups.com, "GeorgeW"
                                <4strokeul@r...> wrote:
                                > Dan-- what's the pitch on that 60" prop that scott is using on that
                                1/2 VW??

                                I can't tell you. There is a Yahoo group for 1/2 VW
                                with lots of posters including Scott. I believe the
                                Ultracruiser and a Prowler trike have flown with the
                                new engine and 60 inch prop. Tip speed comes out
                                over 900fps. There must be some loss of efficiency.

                                --Dan


                                >
                                > GeorgeW
                                > ----- Original Message -----
                                > From: Dan Grunloh
                                > To: Small4-strokeEngines@yahoogroups.com
                                > Sent: Friday, September 10, 2004 10:56 AM
                                > Subject: [Small4-strokeEngines] Re: Sweet Briggs V-twin
                                >
                                >
                                > --- In Small4-strokeEngines@yahoogroups.com, cara@e... wrote:
                                > > The way to get the best performance is to tailor a reduction
                                system
                                > using
                                > > belts or cog belts and use the largest diameter prop you can.
                                Tip
                                > velocity
                                > > can be anywhere between 550 and 650 ft per second.
                                > > A larger prop diameter will give you added thrust for take-off
                                and
                                > climb
                                > > without any sacrifice in top speed if the prop is pitched right.
                                > > Graham
                                >
                                > Thanks I agree. I have seen some long props in use on
                                > competition trikes. I have accepted that the reduction
                                > drive and prop are critical to get the best performance.
                                >
                                > What do you think of the latest 40HP 1/2VW engine from
                                > Scott Casler? They swing a 60 inch prop at 3600 rpm.
                                >
                                > My current Rotax 447 spins that size prop at 2500rpm
                                > at full throttle.
                                >
                                > --Dan Grunloh
                                >
                                >
                                >
                                > >
                                > > Dan Grunloh wrote:
                                > >
                                > > > --- In Small4-
                                strokeEngines@yahoogroups.com, "jeremy_harris_uk"
                                > > > <jeremy.s.harris@n...> wrote:
                                > > >
                                > > > > All in I can see no good reason why any of these V twins
                                > shouldn't
                                > > > > be good enough for ultralight/microlight use with a bit of
                                work.
                                > > > > The larger ones, like the Kohler at 725cc, might be a
                                better
                                > bet,
                                > > > > simply as "there ain't no substitute for cubic inches" at
                                the
                                > end
                                > > > > of the day.
                                > > >
                                > > > Thanks Jeremy. I think your summary is about right.
                                > > > A number of folks have shown the V-twins can produce
                                > > > up to 40HP, at least long enough for takeoff.
                                > > >
                                > > > I'm studying the possibility of putting one on my
                                > > > Air Creation Racer trike. The real question for
                                > > > me will be how much power do I really need for
                                > > > continuous high speed operation? My trike is
                                > > > a little havy compared to a Chaser and I don't
                                > > > know if I would be satisfied with 33-35Hp
                                > > > sustained output. I have a Rotax 447 now
                                > > > and do not run it at sustained full throttle
                                > > > as the CHT tends to climb. Max power output in
                                > > > a speed run is probably about 37Hp with the 447.
                                > > >
                                > > > I eventually need a 4-stroke for the limited
                                > > > fuel tasks in competition.
                                > > >
                                > > > --Dan
                                > > >
                                > > >
                                > > > ### Lets use this list to build a knowledge base for those
                                who are
                                > > > interested in flying with these engines. Don't forget you can
                                > search the
                                > > > messages archive for past discussions. Please keep comments
                                on
                                > subject.
                                > > > Sorry, no attachments allowed.
                                > > >
                                > > > For access to the home page:
                                > > > >http://groups.yahoo.com/group/Small4-strokeEngines/<
                                > > >
                                > > > For direct access to the files area:
                                > > > >http://groups.yahoo.com/group/Small4-strokeEngines/files/<
                                > > > Yahoo! Groups Links
                                > > >
                                > > >
                                > > >
                                > > >
                                >
                                >
                                >
                                >
                                > ### Lets use this list to build a knowledge base for those who are
                                > interested in flying with these engines. Don't forget you can
                                search the
                                > messages archive for past discussions. Please keep comments on
                                subject.
                                > Sorry, no attachments allowed.
                                >
                                > For access to the home page:
                                > >http://groups.yahoo.com/group/Small4-strokeEngines/<
                                >
                                > For direct access to the files area:
                                > >http://groups.yahoo.com/group/Small4-strokeEngines/files/<
                                >
                                >
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                                > ADVERTISEMENT
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                                >
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                                > [Non-text portions of this message have been removed]
                              • jeremy_harris_uk
                                ... Jeremy replies: Dan, I ve run some numbers through Prop Design and it gives a prop efficiency of just 63.4% for a 60 x 25 at 60mph and 900fps tip
                                Message 15 of 17 , Sep 12, 2004
                                • 0 Attachment
                                  --- In Small4-strokeEngines@yahoogroups.com, "Dan Grunloh"
                                  <dgrunloh@i...> wrote:
                                  >
                                  > I can't tell you. There is a Yahoo group for 1/2 VW
                                  > with lots of posters including Scott. I believe the
                                  > Ultracruiser and a Prowler trike have flown with the
                                  > new engine and 60 inch prop. Tip speed comes out
                                  > over 900fps. There must be some loss of efficiency.
                                  >
                                  > --Dan

                                  Jeremy replies:

                                  Dan, I've run some numbers through "Prop Design" and it gives a prop
                                  efficiency of just 63.4% for a 60" x 25" at 60mph and 900fps tip
                                  speed.

                                  I've been trying to optimise the prop rpm, diameter and number of
                                  blades for my trike project, as I'm after maximum efficiency and low
                                  noise if I can get it. I'm pretty much stuck with a 62" maximum
                                  diameter, due to the clearance needed with the ground and the wing.
                                  Even so, assuming that I need 25hp to cruise at 60mph then
                                  the "best" prop is a 5 blader, which seems counter intuitive to me.
                                  The efficiency results I get from Prop Design, for 700fps tip speed,
                                  NACA 4415/Clark Y, tapered chord with 2 degree alpha are:

                                  2 blade = 77.8%
                                  3 blade = 77.8%
                                  4 blade = 78.0%
                                  5 blade = 78.4%

                                  Prop Design assumes that the blade width is reduced as you add
                                  blades, so a 2 blade has a 3/4 radius chord of 2.7", whereas the 5
                                  blade only has a 3/4 radius chord of 1.1". I'm still learning a lot
                                  by playing with this little programme - the snag is that there are
                                  just too many variables to play with! Still, 78% efficiency looks
                                  pretty much as good as you can practically get with this size prop
                                  in this application.

                                  Jeremy
                                • Dan Grunloh
                                  ... Thanks, that s very interesting! Based on those numbers the 60 inch turning 3600 rpm could suffer a 20% reduction in thrust efficiency compared to your
                                  Message 16 of 17 , Sep 13, 2004
                                  • 0 Attachment
                                    --- In Small4-strokeEngines@yahoogroups.com, "jeremy_harris_uk"
                                    <jeremy.s.harris@n...> wrote:

                                    >
                                    > Dan, I've run some numbers through "Prop Design" and it gives a prop
                                    > efficiency of just 63.4% for a 60" x 25" at 60mph and 900fps tip
                                    > speed.
                                    >
                                    > I've been trying to optimise the prop rpm, diameter and number of
                                    > blades for my trike project, as I'm after maximum efficiency and low
                                    > noise if I can get it. I'm pretty much stuck with a 62" maximum
                                    > diameter, due to the clearance needed with the ground and the wing.
                                    > Even so, assuming that I need 25hp to cruise at 60mph then
                                    > the "best" prop is a 5 blader, which seems counter intuitive to me.
                                    > The efficiency results I get from Prop Design, for 700fps tip speed,
                                    > NACA 4415/Clark Y, tapered chord with 2 degree alpha are:
                                    >
                                    > 2 blade = 77.8%
                                    > 3 blade = 77.8%
                                    > 4 blade = 78.0%
                                    > 5 blade = 78.4%

                                    Thanks, that's very interesting! Based on those numbers
                                    the 60 inch turning 3600 rpm could suffer a 20% reduction
                                    in thrust efficiency compared to your ideal prop.

                                    That is a significant amount.

                                    I am also amazed the 5 blade comes up higher. The increase
                                    is small. I too think it should be less. In real world
                                    we probably can't make the blades narrow enough for the
                                    five blade version. In real world the five blades with
                                    bugs on them may not do as well as two blades with bugs
                                    on them.

                                    --Dan




                                    >
                                    > Prop Design assumes that the blade width is reduced as you add
                                    > blades, so a 2 blade has a 3/4 radius chord of 2.7", whereas the 5
                                    > blade only has a 3/4 radius chord of 1.1". I'm still learning a lot
                                    > by playing with this little programme - the snag is that there are
                                    > just too many variables to play with! Still, 78% efficiency looks
                                    > pretty much as good as you can practically get with this size prop
                                    > in this application.
                                    >
                                    > Jeremy
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