After three days of part time work on the plywood frame I want to show you the results.
At first I have build the four vertical sides of the two beams.
You can see these parts (2,4m/8ft long) leaning against the fence.
I used 4mm exterior birch ply and 20x20mm stringers.
It was a little bit tricky to bend the stringers around the curved edges of the panels, while I have to glue and screw simultaneously, 20mm stringers are real stiff.
Then I spend one day with cutting out the bottom panel, marking all the necessary lines and hundrets of points for screw holes, which must be drilled afterwards.
But it's more comfortable to drill all these holes before assembling and makes the build much quicker.
Yesterday two (inner) beam sides were fastened to the bottom.
Several bulkheads and frames are mainly done now.
Now the frame is 3D but I estimate 50% of work is left to do.
In the picture the frame can be seen from the front and right side up.
The bottom is cutted out, where the glue bottle is standing.
This gives the necessary room for the legs of the two pedallers.
The "wings" on the sides are the bottom of the boxes, which will doubleact as side part of the seat bench and swing arm support for the rear wheels.
Then finally the outward sides of the two beams, the top panel from 6mm okoume and the side boxes will complete the frame.