What is best way to mount a tail servo in ARF ?
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From: Houston,
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What is the best way to mount a servo in the tail of an ARF instead of using pushrods ?
Should I just trace and cut out the balsa where the servo will be mounted and reinforce with some ply from the inside, or should I build a little servo tray slightly bigger then the outline of servo and glue it on top of balsa (outside) at the back of the fuse, and then cover back up with some trim sheet or other covering ? This is for my YA 120 size Sukhoi by the way. Just want to make sure I beef it up enough before starting to cut out any balsa.
Any tips, suggestions on how to do this ? A picture would be nice also if available. Thanks
Should I just trace and cut out the balsa where the servo will be mounted and reinforce with some ply from the inside, or should I build a little servo tray slightly bigger then the outline of servo and glue it on top of balsa (outside) at the back of the fuse, and then cover back up with some trim sheet or other covering ? This is for my YA 120 size Sukhoi by the way. Just want to make sure I beef it up enough before starting to cut out any balsa.
Any tips, suggestions on how to do this ? A picture would be nice also if available. Thanks
#2
Stuka depending on where you CG is depends on how much weight you want to add to the tail. Your first question would be the idea situation for a servo. Altough I have never mounted a servo in the tail I have mounted bell cranks and I used light ply for support.
On my edge I used the central hobbies bell crank and mounted it upside down in the tail so that when my servo is pulling I am giving up pressure on the elevators (no rod flexing). I use a single servo mounted at the center area of the CG in main body of the fuse I am using the dave brown carbon fiber rod cut for 4/40 metal rod.
Good Luck
Randy
On my edge I used the central hobbies bell crank and mounted it upside down in the tail so that when my servo is pulling I am giving up pressure on the elevators (no rod flexing). I use a single servo mounted at the center area of the CG in main body of the fuse I am using the dave brown carbon fiber rod cut for 4/40 metal rod.
Good Luck
Randy
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There are many different ways of doing this, obviously. The trace-cut-reinforce method is by far the easiest, albeit not the prettiest and cleanest since the servo will be surface mounted. For most ARF sport planes, this works just fine.
The next step to a cleaner install is to "counter sink" the servo below the surface such that only the servo horn sticks above the monocote. I sometimes build a little hatch cover with a hole on it for the servo output shaft to pass through. Other times, I simply monocote over the servo, leaving a little hole for the output shaft.
The ultimate is to build a rear servo compartment where the rudder and elevator servo are mounted completely inside of the fuselage. This way, only the control rods exit the fuse to connect with the control surfaces. This involves a lot more work since you'll have to build a large hatch cover for the servo compartment.
In any case, I like to mount the rudder servo either on top of the fuse just in front of the vertical stab, or on the bottom of the fuse, such that I can hook up a solid metal rod "pull-pull" linkage to the rudder.
The next step to a cleaner install is to "counter sink" the servo below the surface such that only the servo horn sticks above the monocote. I sometimes build a little hatch cover with a hole on it for the servo output shaft to pass through. Other times, I simply monocote over the servo, leaving a little hole for the output shaft.
The ultimate is to build a rear servo compartment where the rudder and elevator servo are mounted completely inside of the fuselage. This way, only the control rods exit the fuse to connect with the control surfaces. This involves a lot more work since you'll have to build a large hatch cover for the servo compartment.
In any case, I like to mount the rudder servo either on top of the fuse just in front of the vertical stab, or on the bottom of the fuse, such that I can hook up a solid metal rod "pull-pull" linkage to the rudder.



