Lets start at the beginning

Here is the order in which you will have to set up your helicopter:-

1. Reverse Servo’s
2. Check and set up a pitch window mechanically.
3. Centre your pitch servo and set up control throws to match your pitch window and lengthen or shorten pitch linkage so ½ your pitch window has the servo arm centred.
4. Test hover.
5. Set up your Normal mode or hover mode pitch program.
6. Set up your normal mode hover throttle program.

• Pull the linkage off your pitch servo.
• Manually pull the linkage so the washout hub moves as high as it can on your main shaft (or whatever similar linkage binds).
• Put your pitch gauge on your blades and check what pitch you have.
• If you find that you have any more than 15 deg you may have to reduce it.
• Move the washout hub until it bottoms out or until the phasing ring pin is about ½ way out of the washout hub (this may not be the case with your type of helicopter it may not even have a washout hub).
• Check the pitch in this position. What did you have? If you find you have too much positive and not enough negative then you may require reducing your positive pitch range.
• Do this by adjusting the linkages until you have a pitch window that will give you a good compromise what you are really looking for is somewhere between 15 and –10° . You can sacrifice some of the top end if you require more negative. That will only really reduce your reserve pitch for doing Autorotations, you can safely reduce down to about 12° or maybe even 10° if you are sure you will never require reserve blade power to slow down your machine in an auto.
• If you had say 18 to –7° . Push the washout hub until it tops out, then set the linkage length until you have 15° then the bottom you will find will have the extra -3° that you took away from the top and you will have 15 to –10. This is a good pitch window that is very useable and will suit most helicopters.

I have extra pitch because I have overpowered my helicopter for doing 3D which gives me power to get out of trouble (which happens a lot more the more you throw the helicopter around).

 
    3.     You will have to set you linkages up so the servo will move your linkages through your new pitch window. I like to put on a quite long arm on the servo but this is because I’m moving the linkages on my helicopter through 30° .

• Install a servo arm that will give you the correct throw to put your linkages through their pitch window.
• Hold the arm on the servo ball with your hand (so if it binds then it wont hurt the servo it will simply just slide off in your hand). Then with the radio turned on, move the throttle stick to ½ throttle, set the pitch program set to 50% at ½ stick (Start with a new program or reset one preferably).
• Put the throttle stick to full throttle and set your pitch channel end point so that it doesn’t bind the washout hub on the head. I like to do this without the linkage on the ball so I can see how far I have to go before it binds.
• Do the same for your bottom pitch position as well.
• Connect the linkage onto the pitch servo arm, with the throttle at ½ stick you should have roughly ½ your pitch window in degrees on your pitch window.
• If you don’t you may have to adjust the length of the arm off the pitch servo to reach your mixing arm and reset your pitch end points again.
• You should now have the pitch window that you set up in the first step.

 
    4. Now we have to set up our pitch curves. We will start with the Normal mode or Hover mode.
All hovering is done from around mid stick and the more you can move the stick around centre (without it climbing out too fast or smashing to the ground) the better the control over the helicopter. You actually have control over the rate of climb or decent, rather than just bobbing around.

Your normal Pitch curve set up starts with the Helicopter hovering at exactly ½ throttle.

For this you will require an assistant unless you are really relaxed at flying your machine and can take you eyes off for at least 3-4 seconds (sounds short until you try it).

I mean exactly ½ stick not slightly high or low. This should be set on a reasonably calm day, as if it is windy your blades will make extra lift and then you pitch curve will need to be lowered.

• As you have already proficient at hovering you should roughly how much pitch and throttle is required to make your helicopter hover and fly. All we are doing is refining this a lot further. Set the bottom stick pitch to around 0 degrees for now.
• Then test hover you machine. Raise or lower your pitch percentage in your radio Pitch program for normal or hover mode, until your machine hovers at exactly ½ stick.

Recheck by test hovering and you will find the stick has dropped slightly.

If you find the stick is to low then you will have to reduce the hover pitch in your program.

• Hover your machine and only when it is hovering dead still look at the stick position (Not climbing or dropping slightly). Set it so it sits exactly at ½ stick.
• Once this is set if you are a competent flyer you can go to the next step setting your top end pitch. You can do this by going to full throttle and reducing or adding pitch until the helicopter climbs out pretty quickly with a little load on it, then it will unload when the helicopter goes into forward flight. This is both a compromise between both pitch and top end fuel mixture so don’t be to upset if it takes an afternoon to get it right.
• When done we will set the bottom stick position, I do this by completely bottoming my throttle stick (remember before you take off to spin the blades up with the idle trim lever, to keep the clutch engaged) while in full forward flight at height. I then set the rate of decent by adding or reducing pitch until the helicopter descends at a controllable decent rate (floats down gracefully). This will depend on your experience as to how much pitch you like, as a decent rate is a compromise on how much you like to drop the nose in your decent or how windy the conditions are on the day.

Now in a perfect world let’s say your pitch curve started off looking like this:-
    the other spots to around 10% either side of the hover then you will end    

So now as you can see the curve is starting to flatten off. you now have a softer feel on your throttle stick and are able to control your rate of climb and decent a lot more.

But we know that it isn’t a perfect world and at 100% pitch your helicopter engine bogs down at and can’t handle the amount of pitch it is given.

If we go back to our pitch curve of around 25° . +15° and –10° then we would end up with this sort of curve:-

As you can see we have not gone all the way to 100% on the curve only as far as 80%. This will give us around 10° pitch. If you are flying a 30 size machine you may only be able to give your helicopter about 8.5° (as it will bog down if you give it too much) you will have to come back a little further to say around 74%.

If your helicopter climbs out slowly and the engine is screaming you may be able to add some more pitch to your curve. If your helicopter doesn’t descend fast enough then you can add a little more negative pitch to the bottom of your curve. If you haven’t set up your hover pitch up correctly at ½ stick then you will have to raise of lower all 3 centre positions of your pitch curve.

 

• You have set up your end points correctly on the travel adjust setting in your radio program. This evolves pulling off a linkage (either end will do) on your throttle and make sure that the radio doesn’t over travel the linkage on the carburettor, or that it gets enough throttle. The other end point should be enough at ½ idle trim to idle the engine happily cut it out when the idle trim is lowered and engage the clutch and spin the blades when it is raised.
• Now lets get back to the settings 0% is going to idle your engine with the throttle trim at ½ trim. 50% or close to it will give you the right hover RPM and 100% is full throttle without binding the carburettor linkage and doing servo damage.
• Bring your ¼ and ¾ positions closer to centre stick as explained previously, 5-10%.