tail spin

[tgg]

Hello me again, I have just started my raptor 30 to find that when I increase the engine the tail starts to turn anti-clockwise for a closkwise motion rota, when operating the rudder to the left to counteract this it still move in an anti-clockwise motion but slower but when moving the rudder to the right it really starts to spin,I have a hitec eclipes transmitter and a TG-8000 gyro, this is connected into ch4 and the aux into ch5 I have been told this is correct. I have read on this forum somewhere that it could be that the gyro is in the wrong sence can anybody advise please.
Thanks tony

[Stuart]

The rotation is correct, however, the rudder speed is directly driven from the main pulley so its speed is relative to this.

Your Gyro is a normal Piezo version, so you have two wires that come out of the gyro one feeds into the RX under channel 4 for Rudder and the other feeds into the servo.

A great site for Raptors is the following:-

http://www.raptortechnique.com/

When your running a gyro of this nature you have to setup the revolution mixing. You can find an FAQ for it here too:-

http://www.faqs.rcheliaddict.co.uk/faqs.php?faq_id=30

I've copied and pasted some info from the above site to help you understand in greater detail too.

Okay now on to revolution mix, first we need to understand what it's purpose is. To do this lets go through an example of a helicopter setup with no revo-mix and a gyro that is operating in non-hh mode. The first step is to adjust the rudder linkage so that at center stick (hover point) and the rudder trim centered and zero sub-trim that the helicopter does not rotate right or left. This gets the tail blade pitch set to the right angle to compensate for the torque of the main blades. Now at this stage everything seems fine in hover however if you punch the collective to go up then you will see the nose rotate to the left (on a clockwise rotor). So why did the tail not remain straight? Lets look back at what the tails job is. At hover the blades have 5 degrees of pitch. As it pushes against the air molecules there is a certain amount of resistance. If the pitch of the tail blades were at zero degrees then as the main blades rotate clockwise the rest of the helicopter would go counter clockwise. To compensate the tail pitch is set to a certain amount of degrees to counteract the torque and keep the helicopter pointed in one direction. Now if the head speed or the pitch of the main blades changes then the tail pitch will also have to change to compensate for the new load. So if the main blades are at 5 degrees but now turning faster, then it is moving more air molecules. Or if the main blades are at the same speed but now at 9 degrees then again there are more air molecules to push out of the way. In either case the tail will need to change pitch to compensate.

I've copied and pasted info from your transmitter manual to help as well.

RVMX - Revolution mixing
The revolution mixing function mixes pitch commands
into rudder (pitch rudder) in order to suppress the
torque generated by changes in the main rotor's pitch
angle and rotational speed. You can input independent
values for revolution mixing above and below one-half
throttle for each of the NOR, ST1, and ST2 flight
conditions. Revolution mixing is disabled whenever
throttle hold (ST3, operated by the Flt. Cond. switch) is
on. For a clockwise-turning rotor, revolution mixing
should apply right rudder when pitch is increased; for a
counterclockwise-turning rotor, the opposite should occur.
Remember to set the value for both the top and bottom
of the throttle stick's motion.

Note: A procedure for adjusting revolution mixing is given
in a table on page 45.

Revolution Mixing Programming
1. Call up the revolution
mixing screen by
repeatedly pressing one of
the Up Down Edit buttons
until the RVMX window
appears. The function is active with 0% mixing turned on.
Put the throttle stick to its idle position.
2. Now press the Data +Increase key. This will increase
the percentage of RVMX mixing for the low side of
throttle. You may set a value of 0% to 100% for this side.
If you wish to return the mixing percentage to the default
0% value, press the Active/Inhibit (Clear) key.
3. Move the throttle stick to a position above half-throttle,
and change the percentage number to suit.
4. Now verify that the rudder responds both the correct
direction and amount for travel on both sides when
throttle is commanded.
5. Set up the RVMX values for the other flight conditions
(ST1, ST2) by flipping the Flt. Mode switch and repeating
these procedures.

[G524RR]

Gyro in reverse

Hi tony, another leaner here!!
I had this problem with my century hawk!! The problem could be that your gyro and/or your rudder servo are in reverse! :? I asked at my local club and an experienced pilot sorted it for me. As always, ask an expert. I thought I knew it all!!! Nice L/H pirouttes though!!!! :lol: Then it was explained to me. Laws of gravity, etc. Think logically on this one. (if you had no tail rotor) You have a C/W turning main rotor. The tail wants to go Anti-C/W. Cause and effect!! You are set up to add even more to this effect!! If you think about it, it makes sense, honest. :? Your tail rotor is not acting against the cause. I would suggest reversing your gyro and make sure your rudder servo is correctly set. Please don't sue for damages!! only advice as I see it!!! Let me know how it goes.
G524RR

[tgg]

That for the info stuart and g524rr , checked out the site stuart gave me on raptors, and found that the gyro was set the wrong way, the check was to move the rudder stick to the right then the link bar should move towards the front of the heli, then lift the heli by the rota head then move the nose to the left and this should have the same effect which it didn't so swoped the gyro now working ok will test out tomorrow. Once again thanks for the replys real helped out :lol:

[Stuart]

Sounds like your getting there.....