Rudder geometry

[Planehazza]

Hey all,

I want to try moving the ball on my rudder servo in a hole but I can't as the CF rod would bind against the head tank mount. So instead, can I move the ball on the rudder bell crank out a hole and acheive the same result?

I'm assuming it will work? Either way, the servo has to move further to move the tail the same, so it's increasing resolution (albeit at the price of a small amount of speed). If I can do this, do I move the one on the other side out too so it's symmetrical? Or do I leave the ball that's attached to the tail push rod where it is (inner hole), and just move the one pictured to the outer hole?

I want to try Lee's recommendation of moving in a hole on the servo but, as said, I can't

Ignore the muck, I haven't flown or even dusted off my heli since August lol

Thanks

[Planehazza]

So like this:



So I leave the ball going to the tail pushrod (brilliantly modelled by a Qtip) but move the ball conencted to the servo push rod out. If I understand correctly, it means the servo has to push further to achieve the same tail movement, thus achieving the same as result that moving in a hole on the servo arm?

[Eckchaz]

Harry, I thought you said ignore this thread?

I posted on the other thread by you.. How come the CF rod is binding, is the servo ball on the outside or inside of the horn? Its fine doing this.. its just the same using outer holes on the cyclic bell cranks instead of reducing the servo horn ball distance.

Also, I think its better for you to have them equal.. as Im thinking your not actually increasing the res by what you should do but only 50% of what you should actually increase it by. Does that make sense?

[Planehazza]

Harry, I thought you said ignore this thread?

I posted on the other thread by you.. How come the CF rod is binding, is the servo ball on the outside or inside of the horn? Its fine doing this.. its just the same using outer holes on the cyclic bell cranks instead of reducing the servo horn ball distance.

Also, I think its better for you to have them equal.. as Im thinking your not actually increasing the res by what you should do but only 50% of what you should actually increase it by. Does that make sense?

Nope, I said ignore the muck on the heli lol

It binds like this:



It's hard to see on that photo as it's all black, but the rod sits on that plastic header mount at mid stick. So if I add an input, the rod will drop as the arm rotates, which would cause it to flex against the mount.

[Eckchaz]

lol.. My bad mate.. you did say head tank.. I took it as the horns!

I read you reply on the other thread (including the sneaky edit! lol) but lets keep it to this one...

Like yourself, its really hard to explain clearly. My thinking is that you are increasing the res by moving the ball out on the crank.. so you have increased it by lets say double but that is providing the other side is the same distance!

But if you move the outside to the outter hole BUT keep the other side is in the same spot and not the outter hole, you have still increased the res but you have halved what you could have increased it by because the other side travels a smaller distance to move for the same travel.

Is that clearer? So what im saying is that your wanting to increase the res, so why not move both balls instead of increase one side.. so your only gaining half the res when you could have more?

[Planehazza]

lol.. My bad mate.. you did say head tank.. I took it as the horns!

I read you reply on the other thread (including the sneaky edit! lol) but lets keep it to this one...

Like yourself, its really hard to explain clearly. My thinking is that you are increasing the res by moving the ball out on the crank.. so you have increased it by lets say double but that is providing the other side is the same distance!

But if you move the outside to the outter hole BUT keep the other side is in the same spot and not the outter hole, you have still increased the res but you have halved what you could have increased it by because the other side travels a smaller distance to move for the same travel.

Is that clearer? So what im saying is that your wanting to increase the res, so why not move both balls instead of increase one side.. so your only gaining half the res when you could have more?

Yup very clear, but I think it's wrong Sorry! The other half is on the receiving end, so moving that further out will increase the tail slider movement. That in itself is therefore decreasing resolution, no?

[Eckchaz]

I see your thinking behind it now.. Just looking at my bell cranks and what I done to get the blue light... yep, i'm man enough to admit i am wrong! lol!

[Planehazza]

Hehe. Now I've got to convince Lee also So is it OK to have it like that you reckon?

[Eckchaz]

Oh No Harry.. not another debate with Lee

Do you know what Harry.. I am now thinking my original statement is correct and you are wrong!!... The reason for my change of heart is that your tail pitch slider is on a fixed pivot/leverage point.. so what your doing on the the crank (in the middle!) is exactly as I mentioned before.. because the tail pitch/crank IS the receiving end!

Its defo ok to do it this way (look at all the bell cranks on the Outrages) but you will now have to admit defeat to me and Lee!! Pmsl!!

[Planehazza]

Don't you make me draw a picture in paint lol.

Regardless, doing it MY way has acheived what I wanted . The servo i moving noticeably more to get the same travel on the tail slider

Anyways, agreeing with Lee... are you drunk or something?!?

[Planehazza]

I refuse to be defeated:

[chris jones2.4]

That's how mine is Harry, ive moved to outer hole on the crank and about 17.5mm out on the horn

[Eckchaz]

Don't you make me draw a picture in paint lol.

Regardless, doing it MY way has acheived what I wanted . The servo i moving noticeably more to get the same travel on the tail slider

Anyways, agreeing with Lee... are you drunk or something?!?

I aint drunk.. me & Lee are just right.. the reason why your way still works is because you are still increasing the res but not as much as if you moved both balls out like I previously posted!!

Now you've done it.. now I'm going to get drawings with paint!!!

[Planehazza]

It can't though. If the ball's further out, then it's further away from the tail when input is added, resulting in more tail deflection. How is that more resolution?

Imagine the pic above, but with the bell crank at 45 deg, so the left side is pointing up. Now add a second ball to the outer hole on the left. Because it's at an angle and it's further out on the radius of the circular motion (check me out!) it will move further away from the tail resulting in more tail slider movement for the same amount of servo throw. This is less resolution.

[Planehazza]

Well the proof is in the pudding. With the geometry set the way it is, the servo is noticeably moving more for the same rudder movement, and I've upped the Tx gain by 5% so far with no wagging. It holds a lot better too