Ground School - Tail Setup for 3D Flying

Welcome to HeliDaniel.com Ground School - Where discuss tips on RC Helicopter Setup. Today we'll be talking about Tail Setup for 3D Flying

People have asked me how to start 3D flying on their heli, the first thing I'll check is their Tail Setup.

Here's the bottom-line - if you want to do any form of 3D flying, you'll need an excellent Tail Setup.

What's in a Tail Setup?

Here's a list:

1. Gyro
2. Tail Servo
3. Tail Pushrod and Guides
   
4. Tail Bellcrank
5. Tail Slider
6. Tail Pitch Arms
7. Tail Rotor Grips & Bearings
   
8. Tail Rotor Blades

First on the list is the gyro, needless to say you should have at least a reputable gyro that was designed for 3D flying that should be matched with a Tail Servo that's recommended to work with it. I'm not big at wasting money experimenting with Gyro/Tail Servo combos, so I just search the forums for combos that others have success with.

Other that that, there are two other things to understand to have a great tail setup - Silky Smooth and Control Geometry

Silky Smooth
What you really need to do is to make sure that items 2 to 7 move with minimal resistance.

How do yo test that? Remove the Tail Pushrod ball link at the servo end and move the push rod back and forth with your fingers, ideally the pushrod should slide back and forth almost effortlessly.

Tail Servo - make sure that the horn, pushrod and ball link stay clear of each other throughout the servo's entire travel.

Pushrod and Guides - Make it as straight as you can, adjust the guides (if any) to do that. The guides will have to stay put and not move around, use CA or stuff something (I like the tips of cable ties - just cut off the rest of the cable tie once you're done stuffing) between the guide and tail boom to secure it. Oil here helps keep it smooth.

Items 4 to 7 - Check all ballinks, bearings and pivots make sure that they are are not too tight. A balllink sizer tool can be used to loosen ballinks. Check for screws that act as pivot points make sure that they are not too tight, use blue locktite to make sure that they don't come loose.

Control Geometry
Control Geometry varies slightly from heli to heli, but I'll just give some tips which I think would work well in most cases. Most helis will have a 5 to 10 degrees more Tail Blade Pitch in one direction than the other to counter torque produced by the Main Rotor.

Depending on your Gyro, you may want to setup your control geometry in a way that the neutral has some Tail Blade Pitch or none at all, you'll have to do your own research here.

Regardless of how you decide to setup your neutral Tail Blade Pitch, when at neutral, your Servo Horn should be right in the middle of it's total travel. Once you got that, you should make sure that there's no binding at the limits of your your Tail Servo Travel.

You should setup it up so that you max out your Tail Pitch in both directions. Also, make sure that there is no chance of the tail mechanism jamming because of too much Tail Pitch.

The distance between the Pushrod ballink and the servo horn center is another thing that can really affect the performance of your tail setup. I like to set it up so that the tail servo horn deflects about 45 degrees from it's neutral at max tail pitch in both directions. I believe that in most cases it's a good balance between maximizing your servo's resolution and tail control speed (the further out you put your ball link, the less the servo has to move to get to a particular tail pitch = faster response) Again, this varies from heli to heli, so you'll have to do your own research and tests.

Belts/Tubes and Blades
I consider belts and torque tubes more on side of drive systems rather than tail setup, but since it can affect your tail performance, here's some tips.

Belts - Generally don't make it too tight or too lose, follow manufacturer's instructions best you can. Too tight and your tail might oscillate, too lose and your belt might slip and you'll lose your tail's performance.

Torque Tubes - Get a good meshing on your gears so that they don't slip and strip (too loose).

Tail Blades - Plastic is fine for mild 3D, but Carbons are the way to go for all out 3D flying. Get the biggest and meanest blades that can fit on your heli.

Other Important Stuff
Note that for some heli models, it might be difficult to achieve a silky smooth tail setup due to the design of its components, but you could still try some of the above to make it much better.

Use low viscosity oil for lubricating the tail components, higher viscosity oil or grease tends to make things sticky and not so smooth.

Slop, make sure that your tail blades pitch don't move around too much without the servo moving. Replace parts that are too lose or worn out to have a tight setup. (That's still silky smooth!)

Finally!
Getting a great tail setup takes time and patience, but once you get there, you won't regret and you can fly with peace of mind that your tail can take anything you throw at it. I hope this little bit of advice helps! Happy flying!