The New Motor Glider Winter Project Part 2

 With the plug completed for the motor glider fuselage that I wrote about in the first installment of this project now my attention turned to actually making the fiber glass molds to make the fuselage.  With the fuselage being the same shape both on the top and bottom I had to figure out how to make the canopy and the openings where the wing would be attached to the fuselage.  So here is how it all went. 

After the fiber glass on the fuselage plug had cured over night I was able to remove the finished mold for the bottom of the fuselage.  I used a small strip of wood and attached four Styrofoam forms on the bottom of the mold so that it would not wobble around on my work bench when I wanted to make the fuselage bottom in the mold. 

To make the canopy for the top of the fuselage I needed to lay out the shape of the outer edge of the canopy on the plug with a Sharpie pen as shown in the photo above.  

With the guide lines on the plug I next laid down a barrier of modeling clay to make a flange for outer perimeter of the canopy. 

Laying the clay down was tricky to say the least.  But I slowly worked it into shape. Got it nice and smooth or at least the best that I could so I could prep it to lay fiber glass to make the canopy and flange.

Here the fiber glass and resin had been applied to the plug to create the canopy. 

At this point I did not get photos of the next steps in the build. But the simplest way I can explain what I did was that I let the canopy cure over night and then trimmed it off without removing it from the plug.  Then I prepped the rest of the plug so that it I could fiber glass around the canopy and also set up a clay barrier for the opening that would allow access to the servos and make a proper profile for the wing to settle into the top of the fuselage and again make flanges for the mold.  

Here is how the top of the fuselage turned out once I had removed it from the fuselage plug.  I was concerned that I would not be able to remove the canopy from the plug with the top of the fuselage flanges on the plug surrounding the canopy.  

The project making Gods smiled down on me and I had managed to make it all work as the canopy and fuselage top molds popped off of the plug easy as could be.  At this point I was pleased as punch that these complicated parts had turned out so well.  I only needed to make the bottom of the fuselage mold next and that would be a simple task since the bottom had no crazy openings like the top section and canopy.

With the top fuselage mold complete I then had to figure out how to actually use it.  The openings needed to be closed up so that I could make the actual fuselage top. 

To close up the openings I simple took some card stock covered with packaging tape and clamped it to the mold as shown above.  This would make it easy to remove the finished part from the mold as the new part will not stick to the smooth packaging tape thanks to the mold being so smooth and using mold release fluid before laying fiber glass into the mold for the part I wanted to make. 

Here's what the top of the new motor glider fuselage looked like after I had removed it from the mold.  As you can see putting the card stock in to fill the opening worked out very well as now these opening had been closed up.  I needed this to happen so that I could make a proper lip around the openings for the canopy and the wing to rest on when they would be installed for flying.  So I cut these openings out again but left a lip to make it work out the way I planned.

Here the upper and lower halves of the fuselage were taped together to see how the fit up looked.  The fiber glass is thin enough so that the upper portion of the fuselage can be compressed into the bottom portion of the fuselage.  Having both the upper and lower portions of the fuselage be made from the same plug made this work perfectly.  I just taped these parts together at this point just to see if it would all work.  Again another plan had come together rather nicely.  Next to the fuselage you can also see the finished canopy on and off of the fuselage.   

In the two photos above you can see the fit up that I needed to do to get the canopy placed correctly into the top half of the fuselage. Also you can see the cut outs that I had made to the part so that I will have access to the battery compartment under the canopy and the servo area under the wing opening. 

In these images I started laying out the the motor mount, servo mounts, foam core bulkheads and the push rod tubes into the bottom of the fuselage.  This needed to be done before the fuselage was closed up otherwise it would be impossible to get these components into the fuselage. The servo mount was 3D printed and epoxied into place.  The motor mount at the nose of the plane was laser cut to hold the 1180kv motor.  A lot bigger motor than the one I used in the motor glider I flew last year.

Here's a close up view of the motor mount that I came up with.  I needed to be able to remove the motor if I needed without tearing the fuselage completely apart.  Luckily my design worked out very well as I am able to unbolt the motor from the inside of the fuselage without any issues to make it all work. 

Here's a good shot of the motor mount installed into the bottom section of the fuselage. I epoxied the motor mount into the fuselage, let it cure and the sand the fuselage flush with the motor mount in the end. 

So that's about it for today.  As you have seen so far there has been a lot of work that has gone into this build.  A lot of computer work went into the design so it has helped eliminate problems along the way when the actual build started.  Lots of computer time.  But all the planning helps solve issues before parts start to take shape.  So it is all worth the effort for sure that pays off in the end.  Stay tuned for the next installment in the next few days.