My first Heli modification, elevated tail

[hello_hellohello]

Will be experimenting on an elevated tail set up on my Honeybee king I which was left in a kit form when i transfered all my electronics over to my King II. The king I is shaft driven and below are my plans


However i do stumbled into a problem, how do i do the tail control linkage for it to work??

[Super-Hornet]

By the design look, it appears to be ok. U might want to confirm that your 30Degree or 40Degree pinion is messing them well.

It easier to do it in belt. Shaft is possible but more difficult.


EDIT: As for the control linkages, there are 2 ways:
1. Using flexible cable to control it
2. Using an "L" joint/linkage to transfer the control.


SH

[hello_hellohello]

By the design look, it appears to be ok. U might want to confirm that your 30Degree or 40Degree pinion is messing them well.

It easier to do it in belt. Shaft is possible but more difficult.


EDIT: As for the control linkages, there are 2 ways:
1. Using flexible cable to control it
2. Using an "L" joint/linkage to transfer the control.


SH

But how does the control linkages work in these two ways? and which is better?

[Super-Hornet]

Flexible cable
Adv:
1. More suitable for scale because can easily hide the linkages
2. Easier to do.
Disadv:
1. The flexible can must securely fasten in order to prevent it from flexing.
2. May have higher friction than normal rod type.

Rod linkage with L linkage
Adv:
1. Less friction
2. Stronger
Disadv:
1. More difficult to do because u have to develop the L linkage mounting and the routing
2. Maybe uglier.

Using L plate => easiest way is to use servo horn "+" shape. Servo to L plate/linkage is just like normal. Then From L plate to tail control is just like normal servo horn to tail control.

SH

[hello_hellohello]

for the L plate setup, i still kind of confuse. Can elaborate in the form of a simple drawing.

[Super-Hornet]

Look at your "+" shape servo horn.

Align/Place it in such a way it pointed 1, 4, 7 and 10 oclock.

Let the tail servo on the left and tail rotor on the right side.

From tail servo horn, linkage goes from tail servo to L shape's 10 oclock side.
Then from 1 oclock side, another linkage goes from there to the tail rotor.

SH

[hello_hellohello]

okay i get what you mean. thanks. Will be making it next weekend, need to buy an some stuff first. For the mounting branket, what material should i use to keep the weight of the new elavated taill down to the minimum as Honeybee King is a bit tail heavy.

[Super-Hornet]

Lightweight material. It can be ranging from PCB (circuit board) to Carbon Fiber plate to G10 to even aluminium plate.

The trick is not having a single thick and strong plate BUT 2 plate instead.

By using 2 plates u clamp/sandwich these 2 plate on both side in order to gain strength. The strength comes from the mechanical/civil construction word of stressing and compression.

By using sandwich plate (it can be thin), when it is bend, one plate will be "Pull" and one plate will be "Compress". This Stress/Compress will give u a strong foundation...even the material is thin.

EDIT: Take a closer look at what greenhorn has done. That is what I so called sandwich of 2 plates.

SH

[hello_hellohello]

one more question about the elevated tail. During flight for the elevated tail, is it better than the conventional single straight tail boom design or is it more diffcult to control.

[Heli_fanatic]

there is no reason for it to be more difficult i think

[Super-Hornet]

In real heli, the advantage of having elevated tail boom is that, it is more safety for ground crew when there are at the rear of the heli. It is also prevent from tail rotor damage when land in grassy area. That is why u see military heli tend to have elevated tail.

In term of flying characteristic, I would say it is the same... inline tail or elevated tail.

The good thing about elevated tail is that, u can land on grassy area because of the higher tail rotor.

In emergency landing or practicing auto rotate, elevated tail will prevent/reduce the tail boom strike because it does not hit the ground first and then bounce up.

U can also do very scale like flaring landing if u can with elevated tail.

In term of 3D, the bad thing about elevated tail is that u cannot do inverted and having the main rotor/hub grinding the floor surface....because tail rotor will hit the ground first

Some do feel that for elevated tail, the heli will to tilted/slanted to one side when in hover.

SH

[Heli_fanatic]

ive noticed that while watching u fly



Some do feel that for elevated tail, the heli will to tilted/slanted to one side when in hover.

SH

[jansonfinn]

ive noticed that while watching u fly



Some do feel that for elevated tail, the heli will to tilted/slanted to one side when in hover.

SH

even without elevated tail, my heli will also tilted/slanted to one side when in hover, is this normal?

[Heli_fanatic]

yes all helis tend to tilt left so it will look like its tilting right while hovering

[Heli_fanatic]

ccw main rotor direction will cause the heli to tilt right while cw direction of the main rotor will cause the heli to tilt left