| |
|
The drive
chain, shown in the diagram, differs from a conventional bicycle chain in
having cables as the main tension members rather than segmented plates located
by pins. It couples to the chain wheel and sprocket through moulded polymeric
discs that are rigidly attached to the flexible drive cables covering made
of the same polymer. The assembly is light in weight, lubricant free (as
the polymer-metal contact has low friction) and durable. This chain type was
used in the Gossamer series of human powered aircraft where weight is an important
factor in performance, and chain life can be modest.
The sprocket
and chain wheel used in the drivetrain of these aircraft were modified bicycle
components, drilled to lighten their weight. This modifaction was practicable
due to the lower constant forces the drive train experienced during
flight as compared to those associated with a bicycle riding on a rough road
surface. The gear ratio was fixed and selected so that the pilot's optimum
pedaling rate of about 1.5 rps drove the propeller at 100 to 120 rpm. |
|
|
|
|
|
|
|
|
|
|
|
