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The use of electric motors in the operation of control surfaces
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Dear Insideman
I know many systems are "Life Critical" which is why I would just like to explore the problem both good and bad aspects.
To clarify has anyone tried this if so where to get information, if not could you point me in the right direction.
I know many systems are "Life Critical" which is why I would just like to explore the problem both good and bad aspects.
To clarify has anyone tried this if so where to get information, if not could you point me in the right direction.
omg...
Electric motor type flight controls have ONLY been used in a few applications that I am aware of:
to drive trim-tabs
to drive flaps
in "fly-by-wire" aircraft.
NOTE: fly-by-wire aircraft controls are many magnitudes of complexity beyond the "simplicity" of the first (2) applications noted above [which are very straight forward].
Regards, Wil Taylor
Electric motor type flight controls have ONLY been used in a few applications that I am aware of:
to drive trim-tabs
to drive flaps
in "fly-by-wire" aircraft.
NOTE: fly-by-wire aircraft controls are many magnitudes of complexity beyond the "simplicity" of the first (2) applications noted above [which are very straight forward].
Regards, Wil Taylor
Further to what Wil Taylor says above, there are two main reasons why electrical actuation of flight control surfaces is attractive to aircraft makers - very little of which is to do with safety.
1. Power extraction losses. It is believed that by minimising the uses of hydraulic and high pressure pneumatic systems in favour of more efficient electrical power generation, engine efficiency can be significantly improved (since all these systems are ultimately powered by the engine).
2. Weight. The use of new electrical systems (e.g. 270V dc) allows the use of lighter power cables and more efficient power distribution. It is believed that the resulting electrically driven actuators and cabling will weigh less than the equivalent hydraulic system.
While these issues apply to large commercial transports or fighter aircraft, I'm not sure that either of the arguments are valid for light aircraft.
Regards,
Rikman
1. Power extraction losses. It is believed that by minimising the uses of hydraulic and high pressure pneumatic systems in favour of more efficient electrical power generation, engine efficiency can be significantly improved (since all these systems are ultimately powered by the engine).
2. Weight. The use of new electrical systems (e.g. 270V dc) allows the use of lighter power cables and more efficient power distribution. It is believed that the resulting electrically driven actuators and cabling will weigh less than the equivalent hydraulic system.
While these issues apply to large commercial transports or fighter aircraft, I'm not sure that either of the arguments are valid for light aircraft.
Regards,
Rikman
Electric motors as primary actuators in light aircraft flight control systems, except for the use in the trim systems (stabilizer/elevator, aileron, rudder)have not been used in light aircraft. They have been used in the autopilot systems for many years. In either case, the systems are designed to be easily overridden by normal pilot inputs so they can be dissengaged safely in the event of a failure. For this reason (time and altitude required to dissengage safely)most autopilots in light aircraft are required to be dissengaged during takeoff until you rach and altitude defined as a safe one for the system and disengaged at some altitude prior to landing the airplane.
I know several small aircraft manufacturers, like the old Beech Aircraft(Raytheon) have experimented with electric controls for the airplane - particularly the engine controls - i.e. FADEC, but there has been very little interest in building a true electric airplane even with the advantages of the new high voltage DC systems. The weight penalty of all of the electrical power cables and control signal wiring, the batteries, electric motor actuators(probably dual for redundency) would probably outweigh a cable operated mechanical system by a factor of 10 to 1, as cables, pulleys and push rods don't weigh much.
Even in a large airplane such as Lockheed's "Electric controlled C-141", which tested an all electric lateral flight control system before it was shipped off to the boneyard, the common complaint of the test organizations was the electric actuation system weighed in at 15 to 20% above the current hydro-mechanical system then in use. Maybe with newer technology developments, electric type primary flight controls will get lighter and cheap enough for small airplanes but I personally doubt it. Cables and pully systems are simple and real cheap to build(relative!)- and they have worked reliably since the days of the Wrights!
I know several small aircraft manufacturers, like the old Beech Aircraft(Raytheon) have experimented with electric controls for the airplane - particularly the engine controls - i.e. FADEC, but there has been very little interest in building a true electric airplane even with the advantages of the new high voltage DC systems. The weight penalty of all of the electrical power cables and control signal wiring, the batteries, electric motor actuators(probably dual for redundency) would probably outweigh a cable operated mechanical system by a factor of 10 to 1, as cables, pulleys and push rods don't weigh much.
Even in a large airplane such as Lockheed's "Electric controlled C-141", which tested an all electric lateral flight control system before it was shipped off to the boneyard, the common complaint of the test organizations was the electric actuation system weighed in at 15 to 20% above the current hydro-mechanical system then in use. Maybe with newer technology developments, electric type primary flight controls will get lighter and cheap enough for small airplanes but I personally doubt it. Cables and pully systems are simple and real cheap to build(relative!)- and they have worked reliably since the days of the Wrights!
Electric motors as primary actuators in light aircraft flight control systems, except for the use in the trim systems (stabilizer/elevator, aileron, rudder)have not been used in light aircraft. They have been used in the autopilot systems for many years. In either case, the systems are designed to be easily overridden by normal pilot inputs so they can be dissengaged safely in the event of a failure. For this reason (time and altitude required to dissengage safely)most autopilots in light aircraft are required to be dissengaged during takeoff until you reach and altitude defined as a safe one for the system and disengaged at some altitude prior to landing the airplane.
I know several small aircraft manufacturers, like the old Beech Aircraft(Raytheon) have experimented with electric controls for the airplane - particularly the engine controls - i.e. FADEC, but there has been very little interest in building a true electric airplane even with the advantages of the new high voltage DC systems. The weight penalty of all of the electrical power cables and control signal wiring, the batteries, electric motor actuators(probably dual for redundency) would probably outweigh a cable operated mechanical system by a factor of 10 to 1, as cables, pulleys and push rods don't weigh much.
Even in a large airplane such as Lockheed's "Electric controlled C-141", which tested an all electric lateral flight control system before it was shipped off to the boneyard, the common complaint of the test organizations was the electric actuation system weighed in at 15 to 20% above the current hydro-mechanical system then in use. Maybe with newer technology developments, electric type primary flight controls will get lighter and cheap enough for small airplanes but I personally doubt it. Cables and pully systems are simple and real cheap to build(relative!)- and they have worked reliably since the days of the Wrights!
I know several small aircraft manufacturers, like the old Beech Aircraft(Raytheon) have experimented with electric controls for the airplane - particularly the engine controls - i.e. FADEC, but there has been very little interest in building a true electric airplane even with the advantages of the new high voltage DC systems. The weight penalty of all of the electrical power cables and control signal wiring, the batteries, electric motor actuators(probably dual for redundency) would probably outweigh a cable operated mechanical system by a factor of 10 to 1, as cables, pulleys and push rods don't weigh much.
Even in a large airplane such as Lockheed's "Electric controlled C-141", which tested an all electric lateral flight control system before it was shipped off to the boneyard, the common complaint of the test organizations was the electric actuation system weighed in at 15 to 20% above the current hydro-mechanical system then in use. Maybe with newer technology developments, electric type primary flight controls will get lighter and cheap enough for small airplanes but I personally doubt it. Cables and pully systems are simple and real cheap to build(relative!)- and they have worked reliably since the days of the Wrights!
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