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Oct 15, 2019, 09:29 PM
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Discussion

Servo placement


Well I've noticed that for quite a while placement of servos has been done to make things easier to hook up .
But I wonder if servos in the tail of the plane and in the wings actually slow the actions of the plane like stall turns or roll rates.
If you watch a figure skater when they want to slow their spins they extend their arms .and when they want to speed up they pull their arms and legs as near to the centre as possible. Would this not also be true for a plane as well the weight should be as close to its axis and centre of balance as possible .Then the controls would be more responsive .
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Oct 16, 2019, 03:12 AM
B for Bruce
BMatthews's Avatar
Depends on the weight of the servo vs how much weight for a pushrod. Using pull-pull controls certainly shifts the advantage to using the servos in the middle of the model. And a lot of folks use pull-pull for the rudder. But not too many chose it for the elevator.

Anyway, in the old days with basic servos that weighed a good 1.5oz each or more it made total sense to put them in the middle of the model. But now with really good servos available that are only around 9 to 12 gms one really needs to consider what the pushrods weigh compared to the servos with extension leads.
Oct 16, 2019, 07:36 AM
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I'll guess and say that the difference it makes would be hardly noticeable.

I like to place servos so that they 1. provide the most reliable, strong movement of the control surface and 2. are hidden from view.

Carl
Oct 16, 2019, 10:52 AM
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Unless the servos are needed for weight to make the plane balance they should be centered as much as possible. Servos way out on the wing tips would be quite dumb. ...and yes they would affect the roll both starting and stopping. That is why lighter servos are put on the inside of the ailerons.
Oct 17, 2019, 01:18 PM
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On one of my last Builds I shortened the control rods as much as possible to save weight then had to move the battery as far ahead as possible and add Balsa to keep it from moving around so what I saved by shortening the carbon fibre control rod wasn't less weight than the added wood to keep the battery from being eaten by the motor
So on my next one I won't worry so much about getting a servos a little further back and saving weight and then I can keep the battery further back and Save some weight which will make it easier to access the battery.
Last edited by leo turt; Oct 22, 2019 at 03:12 PM. Reason: Spelling
Oct 17, 2019, 06:40 PM
I just want to go fly!
walter3rd's Avatar
Obviously has it’s limits but I really enjoy servo in the center of Wing with Torque rods for ailerons clean lines
Nov 04, 2019, 02:31 PM
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Me too and its plenty strong enough for race planes s more than adequate for most .
.
I Also like the elevator with a hidden control horn or at the least in the centre out the tail end of the fuse .
The only one that is tough to hide is the rudder .


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