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Re: Briggs small block cooling shroud templates

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  • Kev A
    Jeremy Harris in the UK made a glassfibre shroud; I weighed it compared to a stock one when assembling the Vanguard; unfortunately he d based the mould on the
    Message 1 of 6 , Apr 13, 2013
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      Jeremy Harris in the UK made a glassfibre shroud; I weighed it compared to a stock one when assembling the Vanguard; unfortunately he'd based the mould on the earlier shroud which is smaller, with a smaller cooling fan.

      His was half a kilo or 1.1 pounds, the stock shroud is 1.5 kilos or 3.3 pounds.

      You would have to mount the engine then fit the shroud to avoid damaging it, whereas the steel one is strong enough to manhandle the whole engine with.

      Another potential weight loss is the backplate, which sits behind the flywheel, this could be cut from sheet, carbon would be nice, then use small bonded and bolted cleats or tabs to fix to the case.

      Once I got under the legal weight for FAR103 this wasn't pursued, but would be nice to do; need a galssfibre expert to make one.

      Kev

      --- In Small4-strokeEngines@yahoogroups.com, Alan Stockdale <bluejeans725@...> wrote:
      >
      > As Mario suggests, go with fibreglass...
      >
      > Fred and Barney's method....
      >
      > Go purchase a block of modelling clay, it comes in blocks about the size of a shoe box and is pretty cheap stuff. Slice some up with fine wire into sheets a bit thicker than the clearance you want between the engine and the shroud and press over the motor to form the inside of the shroud surface. Any screw holes you want to connect to can have screws in tubes screwed into them so the tube becomes part of the finished shroud. Feel like a kid again getting your fingers and clay tools grubby and doing fine detail work to make it all smooth and right lol. This method allows the shroud to be made any shape, in multiple parts, and to over lap on edges etc and come apart in as many ways as your imagination allows.
      >
      > Choice of resin/cloth covering materials is pretty wide and once you have the clay over the motor you can make multiples to have spares or use for a plug/mould etc.
      >
      > A very basic covering material is car repair polyester filler resin that already has reinforcing fibres mixed in it, comes in tins from the auto store, top of the range covering is heat and vacuum formed pre-preg carbon fibre. Your choice as to what skill level you use, how thin you make it, where you make it thicker to reinforce it etc.
      >
      > There will be some finishing, - grinding edges etc after you start taking shrouds off the clay, and painting etc.
      >  Do the job before the clay dries out and starts breaking. The clay residue comes off the motor very easily of course. 
      >
      > Pack the clay away in a moist cloth in a bag so it doesn't dry out so some other kids can play with it sometime.
      >
      > Have fun....
      >
      > Alan
      >
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      >  
      >  
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      >
      > ________________________________
      > From: Mario Mohl <mario.mohl@...>
      > To: Small4-strokeEngines@yahoogroups.com
      > Sent: Saturday, 13 April 2013 1:58 AM
      > Subject: Re: [Small4-strokeEngines] Briggs small block cooling shroud templates
      >
      >
      >
      >
      >
      >
      >
      > Fiberglass.
      > # of layers to suit weight vs rigidity reqs.
      >
      >
      >
      > On Fri, Apr 12, 2013 at 10:51 AM, Mike <mostsigbit@...> wrote:
      >
      > I announced this in the Pusher vs Tractor thread, but figured it best to start a focused topic.
      > >
      > >I am doing work to replace the stock cooling shroud of my 23hp Briggs V-twin.  The justifications for me are;
      > >I can't count the number of time I've had to remove my shroud to retrieve something that I dropped into it ( yeah- call me butterfingers).  This will allow (with the cutting of a couple zip ties) full access to the flywheel/fan and magneto area.
      > >The original shroud is 3.3+ pounds.  It is low-hanging fruit in the weight saving department to replace this heavy steel shroud with something a bit lighter, obviously with the expense of less durability.  The current steel shroud will support the weight of the motor if tilted onto the shroud, my replacement will not be this strong.
      > >
      > >This is a work-in-progress.  I've gotten no further than cutting cardboard and making rough changes to the template; hole alignment, fold lines etc.
      > >
      > >This template will consist of two parts, the outside ring, and the cover proper.
      > >
      > >I created the ring part by tracing my existing shroud onto paper, photographing it, and importing the photo into inkscape.  From there it was scaled to actual size and traced as a vector graphic.  The cover went straight from photo to scale and trace.
      > >
      > >I originally had the idea of making this out of aluminum and riveting or dzus-ing the parts together, but somewhere arrived at the idea of using coroplast and zip-tying it.  I've not actually made one of either material, but welcome anyone who wants to try or give feedback to the idea.
      > >
      > >I created a folder in the files section;  http://groups.yahoo.com/group/Small4-strokeEngines/files/Briggs%20Shroud%20templates/
      > >
      > >Mike Phillips
      > >Phillips Brothers
      > >
      > >
      > >
      > >
      > >
      > >
      > >------------------------------------
      > >
      > >
      > >### 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
      > >
      > >
      > >
      > >
      >
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