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View Full Version : Tail Pitch Setup 101 (proper tail pitch could affect overall performance a lot!)


timewerx
07-19-2010, 11:40 AM
Tail pitch setup 101:

I believe tail pitch setup is commonly overlooked in setup guides, given that it's automated most of the time - gyro and TX/RX setup usually manage this for you. But do they completely? Unfortunately no.

The gyro could manage the pitch well regardless of tail pitch limits as long as the head speed is okay. But when you're starting to lose too much head speed, for example, pumped the throttle too much and too long in a panicky recovery maneuver, wrong tail pitch limit could make an already bad situation turn really ugly. On the other hand, a good tail pitch limit gives you better confidence in your setup and allows more liberated use of throttle and worry less about losing head speed - usually encountered in aggressive flying such as 3D.

Don't's

-Avoid too much tail pitch. In practice, I generally avoid exceeding 30 degrees pitch both positive or negative (to cause CW or CCW heli rotation). What happens if you exceed that pitch angle, the tail blade starts to stall and generates more drag than force to counter torque, this robs you of significant power from the motor. Tail pitch limit is usually reached when you lose enough head speed, the gyro will pitch the tail blades more to get the same counter torque force. At too high tail pitch, a loss in head speed will make it even worse, as the tail blades becomes a major source of drag, you lose head speed further, until you encounter complete loss of tail hold and even lift from main blades. Really bad especially if you're hurtling towards the ground and ran out of room to try to recover lost head speed back.

-Try not to use neutral/flat/tiny pitch as your pitch limit. For example the main blades spin clockwise and the tail blades are setup to have flat or near flat pitch at maximum left rudder stick. The heli will still piro to the left in that case. It will work but it's not taking advantage of the gyro's full range of operation. It can cause some wagging after a piro, tail hold will be bad in wind gusts, tail will also be bad in hard 3D flying.

Ideal tail pitch setup ('Never Exceed' Tail Pitch Limits)

-If mainblades spin clockwise, max tail pitch to cause heli to piro as fast as possible clockwise is 30 degrees and max tail pitch to cause heli to piro as fast as possible counter clockwise is 20 degrees. Personally, I use 27 / 17 degrees pitch. This may depend on the heli, but try not to exceed 35 / 25 as the absolute maximum tail pitch. If main blades spin counter clockwise, you simply reverse the order of tail pitch limit angles.

Advantages of an ideally setup tail pitch

-Less head speed loss in critical maneuvers - so you can concentrate more on your moves than worrying about collective management and losing head speed.

-Better tail hold in any situation, including wind gusts, flying backwards/side at high speed, etc.

-Tail settles quicker as per gyro sensitivity setting.

-Longer 3D flight time. hovering time will not improve though.

jay2411
07-20-2010, 12:43 AM
Kumusta pare.
Do you use 27/17 degree pitch on the 4G6? What's the easiest way to measure the tail pitch?

salamat

timewerx
07-20-2010, 06:06 AM
Kumusta din at walang anuman! :D

Yes, I use the same pitch currently. I have also used 30/20 with good results. I use a protractor to measure pitch angle of both my main and tail blades, probably not the best, but accuracy is good enough. I wiggle the blades a bit to take slop/free play into consideration.

Maybe you can come over to the Walkera 4G6 section and ask, maybe some of them have a better or more convenient way to measure/set pitch in these tiny helis.

P.S. these pitch angles also work best with a fast tail servo. The stock tail servo on the 4G6 is a slow one and you may need to upgrade to a faster Walkera CB100 servo. Fast tail servo, and optimal tail pitch is a must for 3D flying.
http://www.helifreak.com/showpost.php?p=1916385&postcount=29