It’s a clever system. The constant speed prop on a piston-engined aircraft
works on similar principles: by maintaining a constant RPM as the speed
increases the propellor’s angle of incidence is increased to maintain the same
effective angle of attack. Without this system the thrust would decrease with
the increase in IAS – which is what happens with fixed-pitch props.
Chris
On 26 Sep 2014, at 16:01, Chris Trask <christrask@xxxxxxxxxxxxx> wrote:
>
> The C-130 has a somewhat similar arrangement, at least on the -15
> (H-model) and earlier engines. There is a "ground" range where you are
> controlling the pitch of the propeller(s). Then there is a "temperature
> controlling" flight range where you are controlling the TIT (turbine inlet
> temperature" of the engine(s). And finally there is the "temperature
> limiting" range, wher you are basically controlling the fuel rate and the
> engine controller is adjusting the rate so as to limit the TIT. As your
> airspeed increases, the prop pitch is adjusted to maintain a very limited RPM
> range and the fuel rate is adjusted for more power.
--
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