Aircraft electrical system providing emergency power and electric starting of propulsion engines

In an aircraft including at least two engines each having operably coupled thereto an electric start motor and an engine driven electric generator, an air driven electrical generator, and a battery, an electric engine start system comprising:

• means for supplying electrical power from said battery for starting at least one of said engines;
• means for supplying electrical power from at least one of said engine driven electrical generators to the electric starter motor of another of the at least two engines for starting same;
• and
• means for electrically connecting an alternating current (AC) electrical output of said air driven generator to the electric starter motor of at least one of said engines for starting said engine.

An aircraft comprising:

• an engine;
• an air driven generator;
• means for operably connecting an electrical output of said air driven generator to said engine for in-flight starting of said engine;
• an air driven turbine having variable pitch blades disposed to intercept a flow of air about said aircraft, and configured to produce a rotary output operably connected to said air driven generator for driving said air driven generator;
• said air driven turbine including blade pitch actuator means for adjusting the rotational speed of said turbine by adjusting the pitch of said blades with respect to said airstream;
• first sensing means for sensing a rotational speed proportional to a speed of said engine and generating a first input signal proportional to said speed;
• second sensing means for sensing a parameter of said electrical output of said air driven generator and generating a second input signal proportional to said parameter;
• control means for receiving said first and second input signals and generating:
• a first control signal applied to said blade pitch actuator means for controlling an output frequency of said electrical output of said air driven generator by controlling said blade pitch and turbine;
• and
• a second control signal applied to said air driven generator for controlling an output voltage of said electrical output of said air driven generator;
• and
• wherein said means for operably connecting includes an electric motor operably connected to drive said engine when supplied with said electrical output of said air driven generator in a manner whereby said motor is driven in a soft-start manner for starting said engine.

An aircraft including an apparatus, an electric motor operably connected for driving said apparatus, an air driven generator, and means for operably connecting an electrical output of said air driven generator to said motor for driving said apparatus, said aircraft further comprising:

• an air driven turbine having variable pitch blades disposed to intercept a flow of air about said aircraft, and configured to produce a rotary output operably connected to said air driven generator for driving said air driven generator;
• said air driven turbine including blade pitch actuator means for adjusting the rotational speed of said turbine by adjusting the pitch of said blades with respect to said airstream;
• first sensing means for sensing a rotational speed proportional to a speed of said apparatus and generating a first input signal proportional to said speed;
• second sensing means for sensing a parameter of said electrical output of said air driven generator and generating a second input signal proportional to said parameter;
• control means for receiving said first and second input signals and generating:
• a first control signal applied to said blade pitch actuator means for controlling an output frequency of said electrical output of said air driven generator by controlling said blade pitch and turbine;
• and
• a second control signal applied to said air driven generator for controlling an output voltage of said electrical output of said air driven generator;
• whereby said electric motor is started in a soft-start manner and drives said apparatus when supplied with said electrical output of said air driven generator.