Tag Archives: drawing

Velomobile development drawings: Part 6

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I looked first at the volume of the space taken up by rotating the feet on 175 mm cranks, and compared that to 140 mm cranks. Being so far forward it makes a difference in the volume of the nose and it is easier to push through air.

Also with this I wanted the following:-

  • A single simple form with no jointed surfaces, spats and head-farings. All joints on exterior surfaces of aircraft have fillets between them to reduce vortex drag.
  • The simplest drive line.
  • A faired recumbent bicycle that did not fall over when you try to get in or stop.
  • I wanted it to tilt into a curve to reduce the loads and stress on the wheel system and chassis so they can be lightly built.

!75 mm compared to 140 mm crank frontal areas

140 mm crank rotational volume.

The chassis bounded volume with 26 inch front wheel and 20 inch rear wheels. The chassis will be built from 3.4 mm Corex and 11.5 mm honeycomb board hot-glue gunned with 12 mm conduit.

Velomobile development drawings: Part 5

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I have decided to update this site and describe the line of thought that led to the final design choices, for a velomobile trike.

Getting good airflow over breaks in the surface at the front, is near impossible, so I moved the steering to the rear wheel.

The next stage (body 10) was to try and simplify the form and integrate all the elements using negative pressure and try and do away with surface joints, at the front, as much a s possible.

The wheel spats are more integrated into the nose and the head faring smoothed into the body. I was happy, I had conquered all my demons.

After a short break I returned to this design and gave it a hard critical review. I had lost sight of the friction in the drive line. With so little power available you cannot waste any on extra bearings and changes of direction and weight

Even this simplified form had too many parts and too much wetted surface area.The cross sectional surface area of a reclined human body looking over the knees remains the same. But what about the area of the feet so far forward in a form, what is it, ??? and can it be reduced, ???