Wednesday, February 18, 2015

Carbon Rear Swing Arm/NACA Duct/Milan XL(MaX) Progress

The third try at building a carbon swing arm for the Milan.  It is still a work in progress but very nearly ready.  Still needs to have nicely machined dropouts rather than the present trial ones.  The steel version of this weighs in at 1150 g while this one is 700 g. 

Two views of the NACA duct installed.  The NACA duct itself weighs in at around 30 g.  You end up adding a good portion of that weight to bond it in place.  The duct is made to fit onto the door with a small flange that matches the shape of the door.  The tricky part is cutting the hole to just the right size.   You should be able to retro fit this into existing doors with some care and patience.  I have tried it out a couple of times now  and it moves a surprising amount of air.  I can feel the flow almost at my face once you get to about 20 kph.   If you ride with the hood I would highly recommend adding one.  Also in the picture you can see the larger knee pumps in the door so I can pedal the SL without having to move the BB forward of my favored spot.   I will eventually make a new door as this one was a bit of an experiment with the laminate and I cut out the knee bumps and made them slightly larger.  This door now overlaps the shell so water runs off to the outside.  There is still the rain gutter under it which very effectively stiffens the edge of the cockpit opening.  The knee bumps being larger than the original ones must be slowing me down.  I sure can't tell as the SL is a real rocket even compared to the GT which is already pretty quick.   On some of the hills here it is scary fast.  I use the brakes more than with the GT.  

Lots of progress on the larger Milan.  I may end up calling in the Milan MX.  Most of the moulds are now made and the first two bottom parts are moulded.  I ended up having to remake the rib mould that stiffens the sides.  They are a few days away from being done and then we can carry on assembling the velo.  Looking forward to being able to sit in it and see how big it is.  

1 comment:

  1. Both projects look great! Are you going to make these commercially? I have a friend in the UK who made his own (steel) rear suspension for the SL which works very well but is a bit heavy of course.