Tail rudder servo on the hornet......

[Amaxx]

Well, I have a qeustion for all hornet owners out there.  I have seen a few pictures of the hornets running the tail servo like normal, with a long pushrod, but whats most comman that I seem to see, is the rudder servo right on the tail...  So my question is, with this little machine, does this improve the response of the tail, or is it simply a weight distribution solution   Hope some people have some answers, so thanks for looking

[321]

Some people believed you could improve the tail control (get rid of wag) by installing the servo out on the end of the boom.  But, really, you could get excellent results by mounting the servo where it was intended to be.

[Amaxx]

So, its just a personal preference is all?

[321]

It was wishful thinking.

[Amaxx]

Well, I just wanted to get to the bottom of the situation of it being that usefull or not.  Thanks for your input

[DarkHorse]

Helps weight distribution depending on where you want your battery. With the servo out on the tail you will reduce some mechanical slop though I think most all wagging is due to vibes and slight slop isn't the issue. More mass on the tail means more tail mass inertia that may suit gyro characteristic better and have less jittery wag. The extra mass does effect fast piro rates and causes more stress on the conical gears as a result of abrupt piro acceleration and deceleration. Also the heavier the tail causes slightly reduced forward/backward flip rates, slower than rolling left/right.

[Amaxx]

Hhhmm..... very interesting points you have there.  Glad to hear all these points of veiw.  Thanks

[321]

IMHO, mount the servo where it's supposed to be.  Use a powerful and fast servo like the 3110, but let it be known that an extension wire will have to be used with a micro Futaba servo.  Powerful, because the pitch slider ears bind up and the servo must overcome this.  Work in the pitch slider ears so they operate relatively freely.  A little bit of slop where the ears connect with the blade grip pins is better than it being too stiff.  Use moly grease on the TR hub threads so there is no binding under centrifical forces.  Balance the tail rotor dynamically by unscrewing a blade grip by one thread at a time within reason.  Balance the main rotor dynamically to get a bare minimum of vibration.  Bent shafts will render all your efforts useless.  Use mechanical differential on the rudder servo arm to counter the TR pitch arm's backwards geometry.  Install a good gyro like a GY240 or better.

If you've done all this and all the planets come into alignment, the tail will behave well enough to fly backwards with confidence.  The tail will be more responsive than if the servo were out at the end of the boom and the setup will look better too.

[Amaxx]

Awesome tips   I will have to remember to refer to that post in the future when I own one of these little helis.

[DarkHorse]

> Balance the tail rotor dynamically by unscrewing a blade
> grip by one thread at a time within reason.
This is for an old style Hornet 2 tail hub. The old H2 kit is supplied with a long carbon servo pushrod, the X-3D doesn't give you an option with the kit parts ready for tail mounted servo. This is to accommodate the battery upfront layout.
If you were to purchase a Hornet today... read here.
Got vibes? Try here.