Heat exchanger systems and associated systems and methods for cooling
aircraft starters/generators are disclosed. A system in accordance with
one embodiment includes a first fluid flow path for a first fluid, a
second fluid flow path for a second fluid, and a third fluid flow path
for a third fluid. The first and second flow paths are positioned
proximate to the third flow path to transfer heat between the third fluid
and both the first and second fluids. The third flow path is configured
to allow a transfer of heat between the second and third fluids at a
first transfer rate when the first fluid carries heat at a first rate,
and at a second transfer rate different than the first transfer rate when
the first fluid does not carry heat, or carries heat at a second rate
less than the first rate. Accordingly, when the heat to be rejected by
one fluid is decreased, the heat transfer rate for the remaining fluid
can be increased.