Sunday, August 25, 2013

TerraTrike Velomobile Light Weight Parts And Build Jig

The last couple of days have been kind of hectic here at the Tinker's Workshop with the continuation of the building of the TerraTrike Velomobile project.  In my last post I had completed all of the fiber glassing of the ribs for the body and cut them all to size.  This was a big task in it's self so the work progress over the past few days with the sealing of the cut edges on the ribs has been keeping me busy.  This was needed to be done so that the exposed foam could be protected against the elements and time and the parts and project will last longer because of it.  

This strange looking tool is called a hot knife or loop I don't recall which but it is worth the cost of the tool as it saved me a tremendous amount of work by being able to remove styrofoam quickly and easily.  The tool is plugged into a transformer and electricity flows through the loop of wire and heats it up.  This in turn makes it easy to melt styrofoam like a hot knife through butter.  The loop of wire on the end as you see it I formed into a special shape so that it would remove only about a 1/4 of an inch of foam from a fiber glassed panel. (See the next photo)

 Here I used the tool to start removing some of the foam from one of the ribs for the body.  I simply run the wire along the inside of the parts and move it along until I have removed what foam I want taken out. 

Once all of the parts have had the exposed foam removed that was not needed I then mixed up batches of fiber glass resin and micro-ballons (microspheric hollow glass balls) to form a putty that replaced the styrofoam with a permanent seal.  The putty mixture is cured over night and then sanded to a  smooth surface with sand paper.  This makes a very strong seal and actually makes the part stiffer as well. 

Here more of the ribs are set aside waiting to be sanded smooth.  The white putty mixture really brightens up the parts.  Some of the piece you see here are not fully sealed with the putty mixture as the center section of the foam on the lower portion of the parts will be removed in the final assembly of the framework.   The outer edges of all the ribs will have the skin of the body mounted to them so it will protect these edges as well. 

As you cane see with these two parts there are a wide variety of shapes that are needed for the TerraTrike Velomobile project.  I took all of the ribs at this point in the build and weighed them. The total weight only come up to 9 lbs 2.3 ounces!  I am very happy to find this out as I am right in my guess of the weight of the body.  This total weight of these parts will decrease as I do more finish sanding on the parts and do the final trim of exposed foam sections on the ribs. I suspect that the total weight of the body will be around 20 pounds or so.  So it is looking good so far.

A rather strange looking assembly that I needed to put together was completed today in the shop with a bunch of scrap lumber I had laying around.  This assembly is the build jig for the body.  Or at least the first jig that is needed to get the ribs into their correct locations for the build.  The blue panel in the computer image is a temporary 4 x 8 foot foam panel that is cut with notches so that the ribs can be slid into correct placement for assembly into the body of the velomobile. 
   Once all of the ribs have been connected together the body will be removed from this jig and permanent pieces of foam will be mounted into the framework where the blue panel was originally.  This will make more sense once that portion of the assembly is photographed and I can show you in a later post.

 Here is a couple of good shots of the jig in my backyard.  This jig is a little over eight feet long and needed to be moved to my garage where the final assembly of the velomobile will be completed.  The workshop is large enough to build the velomobile in but the doorways from the shop are not large enough to get it out of the shop.  This is why the project will be moved to my garage where there is sufficient space to complete the project and get it mounted to the TerraTrike.
  As you can see a lot has been done on the project in a very short time.  Total hours has now come up to 147 hours.  But again I must remind you that about 100 hours of this time was just in the designing of the velomobile.  So 47 hours for all of these parts plus the jig is really not to bad.  Should get really interesting once I can start putting the ribs into the jig and you can see the body starting to take shape.  This will have to be put on hold for a few days as it has managed to get rather hot here again in the Midwest with temps over 90 degrees again predicted for the next three or four days.  By then I should have all of the ribs smoothed out and ready to go so check back again and see how I'm coming along with this fun build. Have a good day and keep tinkering!

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