leaded50
Legendary member
Yes.
WING CONTROL SURFACES
- Thread starter Juice
- Start date
So I can buy 180 degree servo and set endpoint lower and make it ~60degrees?
what does it change?
JasonK
Participation Award Recipient
you loose resolution. The signals sent from the TX to the receiver are not analog, they are digital, so depending on the system [based on what I have seen] there could be anywhere from 256 positions to 2048 positions that your TX can sent, if you limit your end points so that it can only go 1/2 the expected range of the servo, then you would 1/2 [so only 128 to 1024 positions] the possible positions that the TX can send... so the servos become more granular in positioning.
in most cases, you probably wouldn't notice this, but it is something to be aware of.
in most cases, you probably wouldn't notice this, but it is something to be aware of.
The 180 degree servos will work just fine. You may lose a bit of resolution but the servo will work.
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You can buy servo extensions that already have the correct connectors, or you can cut your wires and solder extensions in with any wire you want.
Older RC airplanes often had one servo to drive both ailerons because mechanical linkages were cheaper than electronics. This is really where full span ailerons became popular; they are not as aerodynamically efficient, but easier to link to a center servo.
You can buy or make a "Y" harness to drive two servos off of one port on the receiver. If you go this route you have to be careful that the rotation direction is mechanically correct. Reversing one servo in a "Y" harness involves adding some additional circuitry to reverse the signal.
Many planes use two channels to drive the aileron servos. This makes everything easier to hook up, and you can add some flap functionality if you are good at programming your radio and you have enough channels.
Ailerons create a lot more drag when lowered than when raised, this will create a tendency for adverse yaw. Compare this with flaps, half flaps will give you more lift for takeoffs, full flaps will slow you down for landings. Your aileron linkage should create more upward deflection than downward deflection.
The load on the servo is related to the angle of the surface, and the amount of airflow on the surface, and the resistance of the hinges and linkage. The slower you fly and the less control deflection you need, the smaller your servo can be in proportion to the surface. It also helps to build so the linkage doesn't bind.
Control surface linkages are just a pair of levers. Attach the rod close to the pivot on the servo, and the motor torque gets converted into more force and shorter travel. Attach the rod far from the control surface hinge, and the rod's force gets converted into a large torque on the control surface and a small angular deflection. Reverse one or both of these to get more deflection, faster travel, and more load on the servo.
Beware when a rotating linkage goes near top dead center or bottom dead center. If on the servo side, it will create a large amount of force with little motion. When it goes past center, you will actually get reverse travel. You can use this in your favor to get unequal aileron travel. If the linkage goes past center on the control surface side, you will get a plane the surely crashes when the control surface moves really quickly in the wrong direction.
Older RC airplanes often had one servo to drive both ailerons because mechanical linkages were cheaper than electronics. This is really where full span ailerons became popular; they are not as aerodynamically efficient, but easier to link to a center servo.
You can buy or make a "Y" harness to drive two servos off of one port on the receiver. If you go this route you have to be careful that the rotation direction is mechanically correct. Reversing one servo in a "Y" harness involves adding some additional circuitry to reverse the signal.
Many planes use two channels to drive the aileron servos. This makes everything easier to hook up, and you can add some flap functionality if you are good at programming your radio and you have enough channels.
Ailerons create a lot more drag when lowered than when raised, this will create a tendency for adverse yaw. Compare this with flaps, half flaps will give you more lift for takeoffs, full flaps will slow you down for landings. Your aileron linkage should create more upward deflection than downward deflection.
The load on the servo is related to the angle of the surface, and the amount of airflow on the surface, and the resistance of the hinges and linkage. The slower you fly and the less control deflection you need, the smaller your servo can be in proportion to the surface. It also helps to build so the linkage doesn't bind.
Control surface linkages are just a pair of levers. Attach the rod close to the pivot on the servo, and the motor torque gets converted into more force and shorter travel. Attach the rod far from the control surface hinge, and the rod's force gets converted into a large torque on the control surface and a small angular deflection. Reverse one or both of these to get more deflection, faster travel, and more load on the servo.
Beware when a rotating linkage goes near top dead center or bottom dead center. If on the servo side, it will create a large amount of force with little motion. When it goes past center, you will actually get reverse travel. You can use this in your favor to get unequal aileron travel. If the linkage goes past center on the control surface side, you will get a plane the surely crashes when the control surface moves really quickly in the wrong direction.
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