Ive been toying with the idea for some time of installing a HH gyro on my Cx2 for scale flight, and after seeing a few others who succesfully did this, I decided to share how I managed to get mine to work. I want to thank rbinc for all of his "behind the scenes" help with this.
The only reason I did this was because I fly with a DX7. Most bind the DX7 in the airplane mode for simplicity but this doesnt allow you to access certain throttle curves and throttle hold modes available in the Heli mode. There are issues sometimes with the stock CX2 gyro in the heli mode on the DX7 that causes the tail to wag uncontrollaby on the CX2 and I was having these issues. Unless you just want the experience of doing this, I cant think of any reason to install a HH gryo on this heli because the stock one works very well.
Fuselage mods: I used the E-Flight Jet Ranger body which is a nice one piece unit. BladeCx2Runner descibed issues in another thread of the rear of the canopy coming into contact with Xtreme blades. Mine was very close, so I drilled new body pin mounting holes about 2-3mm diagonal of the originals to pull the rear of the body down just a bit to give a little more clearance. Stock blades should be fine. Also the body pins slide out over time so small peices of small size fuel tubing hold them in place
I also installed a scale lighting set from here:http://flightlights.net/RcHeli.htm
They are expensive but are the smallest and brightest I have seen and they are plug and play on the reciever. One light strobes and the others remain on, so the scale apperance is really cool. I secured them into the body using several CX2 canopy grommets so I could remove them later if needed. I also did not like the open window canopy style so I created windows on my own and covered them with dark blue self adhesive monokote from the LHS airplane section, and trimmed the front with silver auto pinstripe tape.
Gyro install: The Gyro I used is an E Sky EK2-0704A HH gyro that is about $38.00. Its very small and weighs about 8 grams in the case.
This gyro has no "reverse" function but if you install is in the position shown, it will be working in the correct direction. Simply unplug the rudder plug from the 3&1 to the reciever and plug it into the gyro. Then plug the gyro into the rudder port on the reciever and plug the single wire gain plug from the gyro into the "gear" 5th channel port on the reciever. You must plug the gain plug in or the gyro will have to be adjusted manually using the gain pot on the gyro and will only work in rate mode no matter what the setting!!! I wanted to use the gear port to run my lights instead of gain, but doing this would cancel out the whole purpose of getting the HH gyro, so Im running the lights on the 6th channel "Aux" port on the reciever (thanks Sirion!) The lights turn on when I raise the throttle. Your gyro gain will then be controlled by the 5th channel knob on your radio. You must initialize the gyro in HH mode (gain over 50%) and make sure your rudder trim is centered so the gyro know where neutral is.
Make sure that you turn both the gain and proportional pots on the 3&1 all the way off (full left) to allow the new gyro to have control.
I was very dissapointed at first because I could not get the gain above 80% and this was not enough to hold the nose and any higher gain made the heli crazy. I discovered that I had a few broken gear teeth and this was causing a high frequency vibration that was interfering with the gyro in high gain. I replaced the gears and now I am running at 95-98% gain and she holds very well. There is a very slight nose drift to the right after the gyro heats up, but one click of left rudder trims stops the issue.
Its important to remember that the gyro will initialize immediately when the battery is plugged in before the 3&1 will, so you must have the heli sitting on the ground and not moving at all when you plug in the batt.
The heli now flys perfect with my DX7 in Heli mode and now I have access to all my smooth throttle curves that keep the heli from being so throttle sensitive and twichy up and down when hovering. I still have all the bling hidden inside the body now but the increased weight seems to really make her feel more scale. She now weighs in at a hefty 8.6 oz but still gets 8-9 mins of scale flight from a DN 900 Mah pack and leaves 3.6 volts per cell after the fact.
Thanks again for all the tips and help picked up from everyone in the forum.

Great write-up, great qualifiers on why we do this.

Best Regards

Originally Posted by rbinc

Great write-up, great qualifiers on why we do this.

Best Regards

Thanks rbinc. Couldnt have done it properly without your help

Awesome. I may have to try this with my "blinged" out CX2 also. Is the flying characteristics noticeably different? I feel the stock setup almost flies itself, I think I read somewhere a HH on the CX2 almost slows things down or less responsive...is this true?

Oh yeah, do you know where the cheapest shipped price would be for the Gyro?

Originally Posted by puma1824

Awesome. I may have to try this with my "blinged" out CX2 also. Is the flying characteristics noticeably different? I feel the stock setup almost flies itself, I think I read somewhere a HH on the CX2 almost slows things down or less responsive...is this true?

You are correct. Its almost the same as the stock gyro, but the stock setup simply would not work with my DX7 in heli mode. The HH does not start to drift when the batt drains down so the nose holds better during flight. One click of trim during flight is about all that is needed and minor flying of the nose just like you always would. The HH gyro (as with all HH) causes the piro rate to slow when you run high gain. I still have good rudder control , but its a bit more "spongy" feeling and the tail starts and stops are not so jerky like the stock gyro. Its actually much more scale like and smooth.
I wouldnt spend the money just to do this but for me it was worth it to be able to use my throttle curves. I now have have flattened out the throttle curve at hover, so gone are the up and down twitchy hovers with a normal linear curve. The heli holds exactly where I want it and small throttle changes do not cause it to jump to the ceiling or fall to the floor. The DX7 makes this little heli a completely different bird

Originally Posted by puma1824

Oh yeah, do you know where the cheapest shipped price would be for the Gyro?

I got mine here: http://www.helidirect.com/product_in...oducts_id=1743

They are about the same price everywhere though

They are a little heavier and slower but more torque and they do not have the frail leads of the S60. Was disgusted to get my Bell together and lose ANOTHER S60 because the ground lead broke. In all fairness to E-Flite, it's only when you unplug/plug the S60 in a few times that the "hair-gauge" leads fail.

The HS-55 will fit:

Remove the rib and shoulder on the rear of the shaft housing.

Use a CX (not CX2) upper servo/canopy mount.

Space the ail servo 2 mm from the servo/canopy mount on top with 2 mm plastic. Bottom tab of servo is removed like the S60/S75

Space the bottom of the ele servo with 3 mm. Tab is notched like the original S60/S75.

Rock solid great servos that will never cost me another near miss because of lead failure. S60 is ligther and faster than the HS-55 but the Hitec has more torque (none of which is an issue here in the CX). But the leads are durable and it is usually cheaper than the S75 (same dimensions used in the original CX and Blade CP/CP Pro)

Regards

Originally Posted by rbinc

They are a little heavier and slower but more torque and they do not have the frail leads of the S60. Was disgusted to get my Bell together and lose ANOTHER S60 because the ground lead broke. In all fairness to E-Flite, it's only when you unplug/plug the S60 in a few times that the "hair-gauge" leads fail.

The HS-55 will fit:

Remove the rib and shoulder on the rear of the shaft housing.

Use a CX (not CX2) upper servo/canopy mount.

Space the ail servo 2 mm from the servo/canopy mount on top with 2 mm plastic. Bottom tab of servo is removed like the S60/S75

Space the bottom of the ele servo with 3 mm. Tab is notched like the original S60/S75.

Rock solid great servos that will never cost me another near miss because of lead failure. S60 is ligther and faster than the HS-55 but the Hitec has more torque (none of which is an issue here in the CX). But the leads are durable and it is usually cheaper than the S75 (same dimensions used in the original CX and Blade CP/CP Pro)

Regards

Good to know rbinc. The original servo mounting tabs on mine cracked and now the plastic cases on the replacements keep popping open. I removed them and covered them in clear tape which should do fine, but at least I know there are alternatives to the stockers if they break again.
Now if I could only get the tiny crap Walkera electronics in my 4#3 repaired and working!!!

I just installed a Telebee GR201 HH gyro on the tail boom mounting plate (behind the servos). The prop/gain on the 3-1 are turned fully ccw. When I turn up the gain on the Tx 5th channel the tail shakes violently at times, then smooths out. Is this a mechanical feedback problem?

Originally Posted by jswnhart

I just installed a Telebee GR201 HH gyro on the tail boom mounting plate (behind the servos). The prop/gain on the 3-1 are turned fully ccw. When I turn up the gain on the Tx 5th channel the tail shakes violently at times, then smooths out. Is this a mechanical feedback problem?

When you say "shakes" does this mean that the tail jitters or wags a lot when flying with the gain up high and then suddenly stops and becomes normal, or just the fact that this happens with high gain all the time?

Its normal for the gyro to "search" when the gain is too high. It will also do this if the gyro picks up a lot of vibration on the heli. Most people raise the gain until the heli starts to do this searching and then just back the gain down just a bit until it stops. This gives you the highest gain setting without going over the line with it.

Im not familiar with the gyro you have but the rules are pretty much the same for all of them. Your gain should be at least above 50% at all time to be in the HH mode.

Originally Posted by Xrayted

When you say "shakes" does this mean that the tail jitters or wags a lot when flying with the gain up high and then suddenly stops and becomes normal, or just the fact that this happens with high gain all the time?

Its normal for the gyro to "search" when the gain is too high. It will also do this if the gyro picks up a lot of vibration on the heli. Most people raise the gain until the heli starts to do this searching and then just back the gain down just a bit until it stops. This gives you the highest gain setting without going over the line with it.

Im not familiar with the gyro you have but the rules are pretty much the same for all of them. Your gain should be at least above 50% at all time to be in the HH mode.

That's another important criteria Xrayted; if the helicopter shakes at all, solve this before installing the HH gyro. Vibration confuses the piezo and it will never perform well.

Good point.

Agreed rbinc. I had the same issues with my install which turned out to be broken gear teeth. Im thinking his issue is actually gyro search and not actual heli shaking or vibration based on what he is saying, but its hard to know for sure without details.

Hope your doing well

When I back down the Tx gain, things smooth out. Not sure how to determine if I cross the threshold to standard mode.

Currently at 190 g w/o battery. With DN 850mA, 15C lipo the total is 229 g.

Originally Posted by jswnhart

When I back down the Tx gain, things smooth out. Not sure how to determine if I cross the threshold to standard mode.

Currently at 190 g w/o battery. With DN 850mA, 15C lipo the total is 229 g.

Then you are definitely getting gyro "hunt" from the gain being too high. Push it up until you get the jitters and then back it down just until it stops. If you plug the batt into the heli with the 5th channel gain dial ( I assume you are using 5th channel remote gain now) at at least 50% gain or higher (or above midway on the dial), then you are in HH mode. You can start in HH and back down below 50% to rate mode (why do this as its just what the stock gyro was and makes no sense) but you cannot start below 50% (rate mode) and then dial up into HH. The gyro must be started in HH mode to use HH. Make sure you have your rudder trim set in the middle when you power the heli up.
What are your experiences with this HH gyro? does it hold solid once you get the gain down and the tail wag stopped? Do you see any better than you had before? In HH mode the rudder will feel much slower and smoother which is perfect for scale flying. The stock rate gyro works very well on the CX2, so I would imagine your HH is just slightly better than what you had unless your flying scale

I have barely had time to get airborne for testing and am going out of town this weekend. I will try to post results early next week.

The rudder trim is centered. Not sure if there is any drift. Using the stock gyro I started at nearly full left trim and it would drift to somewhat right trimmed over a 10 min flight.