HOWTO Wiki Overall CX and CX2 Setup

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Contributed by a friend in the RCuniverse group...

Heli Setup: Tips, Tricks and Advice

A compilation of compelling comments from the incompetent flier known as, Soloboss

In fairness, everything here is not an original thought. I do know that this stuff works. The information about flybar mods and blade clack that I’ve published here are my ideas and I’ll take editorial (but not financial) responsibility for those comments. There is no serious money involved in any of these modifications. Top dollar item is the aluminum heat sink with the thermo paste. And the flybar collars are a couple of bucks for the set of 4 (including the wrench to tighten them). And I have the aluminum center shaft / flybar hub although it’s certainly not a requirement for good flight. In the forum, I've written a number of articles about my experiments and things that I believed at one time to be true. And sometimes I was wrong. The guys in this forum have always been enthusiastic about my discoveries and polite about my errors. And we all learn. Note that I’m not a helicopter designer and there is no guarantee that this will work for you. If you damage your heli, don’t send me the bill. Talk to your buddies. Talk to the local hobby shop. If they tell you not to do some of this, then don’t. And when you trim a heli, wear eye protection. All of the mods listed below have been done to my CX and the only problem I have is that the little bird has so much energy that I can hardly keep up with it. It’s rock solid and stable. I’m LHS approved (LOL).

Blade CX / CX2 - Why it works, and why that’s bad

The problem we have with the CX / CX2 is that the designers did a really good job. The heli is offered as an indoor or zero-wind trainer. The upper rotor controlled by the flybar works to negate the affect of the lower rotor, which is controlled by us via the servos. It's a balancing act resulting in phenomenally stable hover properties. My hat is off to the designers. The placement of the linkage on the horn is factored against the spinning mass of the flybar, and those two forces are balanced so that any movement you input to the lower rotor is countered by the movement of the flybar / upper rotor. Moving the linkage on the servo horn should be among the last things you do, not the first.

The reason that the heli moves at all is due to the fact that you can 'surprise' the flybar. It takes a second or two for the flybar to realize that you changed the balance of the heli by changing the lower rotor blade angle. The heli moves until the flybar catches up and stops the heli. You have noted that if you move a stick suddenly the heli moves pretty good, but it soon stops and hangs motionless in the air even though you are demanding that it move via the right stick position. Some try to get more positive response by moving the linkage further out on the horn. OK, so do that and you can give the heli a bigger surprise. And it responds by moving more aggressively - until the flybar stops it again.

Balance that 4-in-1 in 10 easy steps

First a message for the LED color curious. I have read this question on the forums repeatedly. 
All of the flyers agree that the 4 in 1 LED does change from Green to Red under full power. 
Reduce the power and it returns to green. 
I’m guessing that the Green / Red is a voltage indicator. 
The lower the battery voltage the easier it becomes to make the greenie go red. 
With a fresh battery, when you apply maximum power, the current goes up, 
the voltage drops and the light goes red. And they all seem to do it. 
OK? So now let’s get on to getting that 4 in 1 balanced.

The PROPORTIONAL adjustment that we talk about is covered in good detail in the owner's manual. But that manual just isn't giving you the information that you need. The steps below will provide you with a process that will get your proportional adjustment set properly. No drift, no change. When it’s done correctly it doesn’t change unless your motor current draw changes. So this is pretty much your ticket to freedom from messing with it.

The information in the manual is in the section dealing with the heli’s ability to hover without rotating. I have a CX, not a CX2 but the operation is the same. The PROPORTIONAL trim screw is the lower one on a CX and the rear one on the CX2. In short, the 4 in 1 is the radio receiver and the motor rpm balance adjuster. The 4 in 1 is under the front canopy. It's the box with the blinking light that you see when you turn the heli on.

The canopy must be removed to access the 4 in 1. Or you can shoot a hole in the canopy to allow access, but you do want to miss the 4 in 1. Even a 22 caliber bullet is large enough - LOL. Seriously, I did put a small hole in my canopy to allow access to the 4 in 1 for the initial setup. Once I adjusted it using the steps below, I’ve never touched it again. The purpose of the adjustment is to balance the rpm of the upper rotor and the lower rotor so the heli will fly without turning (yaw). Here are a few common tips.

• USE NEW BLADES! If there are ANY imperfections in the blade edges it will affect the balance. Balance the blades. Pick a pair of blades, snap them together, and balance them on the balls where the linkage connects. I use a little packing tape on the underside of the light weight blade out near the end of the blade. Add weight to the light weight blade. And be sure the upper rotor is tracking correctly. Yes, there is a section below that covers this little detail. It’s called GET ON TRACK.
• Remove the front canopy so you can access the proportional screw in the 4 in 1. The canopy has nothing to do with the rotation trim adjustment.
• Fully charge the battery, and then operate the heli for one minute before adjusting the 4 in 1. This will bleed off the very high initial charge in the battery so the adjustment will be valid through the mid-range of the charge. It may be off a little for the first minute and at the end of the flight, but it should be good in the middle of the battery charge.
• Throttle up and determine whether the heli turns clockwise or counterclockwise, viewed from above.
• Unplug the battery from the heli. The adjustment only registers in the 4 in 1 when the heli arms, just after you plug the battery in. If you adjust it with the heli powered up, the change won’t register until you pull the plug, then power it back up.
• If the heli rotates clockwise, turn the PROPORTIONAL adjust screw counter clockwise. Don't turn it more than just a very little bit. If you see that the screw turned, that was too much. If you wonder if it turned, that’s about the right amount. Yep – it’s Really Sensitive.
• Plug the battery in and check for rotation. Continue to adjust in very slight amounts until you get it right. Be sure your stick is centered and the trim is centered. It only takes a second to determine if the heli rotates or not. Altitude doesn’t matter. Adjust until you get it spot-on. After this, you'll not ever adjust it again. Unless you change the body, then you might have to mess with it a little. Maybe.

Following are additional tips that will make a huge difference in the stability of the heli:

• The use of the motor heat sink with the heat sink compound will make the motor temperature more stable. Imbalance of the temperature of the two motors affects the balance of the output of the motors and will appear as though the 4 in 1 is out of adjustment. Until you control the motor temperature, you'll never get the 4 in 1 to hold a stable heli rotation.
• If you have the ability (and most anyone does) remove the 4 in 1 (it's just held on with double sided tape), remove the two screws that hold the cover on it, drill some vent holes in the cover, replace the cover, stick it back in place with double sided tape. This will cool the 4 in 1 and make it more stable. If tape scares you, take it to a buddy. If he chases you with the demon tape, get a new buddy.
• If you use multiple battery packs, you will want to ventilate the canopy to push cool air to the motors and the 4 in 1, but I don't know that it's an issue for just one battery, and it's certainly no issue when you are adjusting the 4 in1. Some say that you must also vent the lower body to let the air out. Maybe so. I think that the exhaust air blows by the battery and cools that as well. And we all want to be cool.

Once you get the 4 in 1 adjusted, it doesn't change. If it seems out of whack after a few rough landings, look for bent shafts, chipped blades or anything that will affect rotor speed - but don't start by messing with the 4 in 1.

Get On Track

Tracking is a HUGE issue with a helicopter. But it's easy to tweak - let's get to it. The two blades of the upper rotor have to track in the same plane. Looking at the side of the heli with the rotor turning, PUT YOUR EYE PROTECTION ON, then view the upper blades. The faster the blades are turning the more bad tracking shows. At low RPM, the tracking will look great because the blades are just going around. At high enough RPM for the heli to lift, the imbalance of the pitch of the two blades will become obvious. One blade is lifting and the other is not, thus the tracking is off. Bad tracking also reduces lift, makes a bunch of noise and screws up the proportional setting. Just as your manual says, to adjust the tracking, pop the adjustable link off the upper blade and turn one end of the link to make it longer or shorter. Which way to turn it? Turn it the right way, of course. If you turn it the wrong way, tracking gets worse. When you get it right, you’ll know it: The blades are in line and the noise goes down and the lift increases and the sun comes out and the birds sing and that cute little lady down the street . . . well you get the idea. It’s just better when it’s right.

TRIM for a Solid Hover

Does your heli lift and head for parts unknown? Or does it lift and just sit there the way it was designed to do? As odd as it sounds, when I trimmed mine I didn't even look at the swash plate. Level? How level and compared to what? I can't tell. Heck, I 'm a rodeo clown, not a heli mechanic, so I came up with my own way to do it.

I started by getting the 4 in 1 absolutely spot on. There is no rotation in my heli, so all I was dealing with was fore / aft / lateral movement. And that's where the trim slider positions told me what to do. I don't fly my heli to adjust it. I use a slick table top and power up just to the point where the heli slides across the table. No reason to have the heli fly away for this adjustment. If it won't 'ground hover' it won't hover in the air. Adjust until it will sit still on the table when you throttle up. OK, so it will sit fairly still. It will never be perfect. In my case the heli always lifted and went right. I could almost correct it with the trim. With the linkage in the second hole (the way they come from the factory) 3 turns of the linkage equals the movement of the trim slider from center to fully one direction (i.e.; moving the trim from fully left to mid range = 3 turns of the linkage). So I turned the linkage 3 full turns and flew again. I needed one more turn and it was just right. Then I did the same with the other link. When I was done, the heli will hover with no rotation and no drift with the sliders centered. It's just a few adjustments. Takes about 15 minutes on a bad day. OK, so there is no drift indoors until the heli makes its own wind - and that wind makes it drift.

(Some change to the CNC swashplate. CNC offers bling. CNC plates are heavy. OK, just a little heavy if you’re counting and the weight seems to have no negative issues. CNC plates are strong. Moving your servo control rods to the 4th hole breaks / separates plastic swash plates. My heli has crashed as hard as any and I’m still on my factory swashplate. And when I break it, I’ll get another plastic one.)

A Case of the Jitters

”GLITCHING” That’s the tendency for the heli to jolt the blades for no particular reason. And the power sometimes ‘drops out’ for a split second during flight, and it makes me really nervous. I'll just add a couple of thoughts. Most likely the cause is an electrical surge caused by magic. I have had my heli sitting on the floor armed and ready and if I reach for it, one of the motors will spin. Only for a micro second (or maybe a millisecond), but it's an electrical glitch coming from static electricity or something. It has happened several times to me. If you were hovering and that same 'glitch' happened, you might see a tail twitch or an altitude drop of 12”. Don’t know what it is. I have never seen a post offering any solution for the problem. Some helis do, some helis don’t. I thought the CX2 with the high frequency radio was supposed to address that. I hear it still happens. Some glitch frequently and violently. Mine doesn’t. If it did it would be in the trash and you would be reading someone else’s paper. I don't know that there is anything you can do about it. But I’m just a stupid human, not an electron.

When the temperature goes up, stability goes down – so cool it.

Something that is not stressed enough in the owner's manual is how fragile the 4 in 1 is. Remember; ALWAYS give up when you know you are going to crash. Shut off the throttle just before impact. DON'T EVER command the motors to try to turn when they can't. A new 4 in 1 costs $50.

Things to do

Add the motor heat sink and the thermal paste that sticks the sinks to the motors. Cool motors are cool. Vent the body. Airflow at the heat sinks is good. I've installed a few photos below with a little help from a couple of forum friends. If you poke them they get much larger. Your back button will put everything back into perspective.

Vent the 4 in 1. It's very heat sensitive. A stable 4 in 1 = stable rotation control. And at $50 a pop, cool is a good thing. There are posts all through the forums covering these things.

The CX is a great little heli and it's pretty rugged, but the electrics need special protection. The shiny bits in the 4 in 1 are the innards. There’s very little of the 4 in 1 case left. (The whole thing looks neater from 3 feet away.)

That 4 in 1 takes all of the current for the motors and it gets hot. It will be damaged in just a second of full power with the blades stuck. You really do want to ventilate the cockpit and the case for the 4 in 1. Several of the guys have written about how that's done. And if you search my posts you will read about it again. And ventilate the 4 in 1 case. And add the heat sink and heat sink compound. It all makes a difference. I know, you probably read this same stuff elsewhere in this paper. Well, it’s still true. If you just skip through this paper I didn’t want you to miss it so.

You say you’re unbalanced? I can fix that

The blades have linkage balls on them. The blades will lock together without screws if you are gentle – or put the screws in. Be happy. Get a couple of soup cans and set them side by side spaced so you can put the balls of the blades on the rim of the cans. The blades will balance on the edges of the cans (or glasses or steak knives or whatever). If one end of the blade assembly is light, add a strip of tape to the underside and smooth it out completely so it doesn’t mess up the aerodynamics of the blade. Keep adding lengths of tape until the two blades sit level. I use packing tape in 1/4” wide strips near the outer end of the blades. Scared of tape? Stuck-on peanut butter works. So do boogers. But tape is smoother.

Get Outa the Toilet!

TBE. Toilet Bowl Effect. ‘Round and ‘round she goes in a larger and larger circles and you can’t stop it or control it. Like, wassupwithat? A large part of TBE is caused by friction at the balls on the upper blade where the flybar linkage connects. From the factory there is often a ring of 'flash' plastic around the ball. When you snap the flybar linkage onto the ball there is just a bit of resistance. GET RID OF THAT FLASH. Use a knife and scrape it or sand it or whatever, but ANY resistance in the flybar linkage will cause TBE. And the less the flybar weighs, the worse it is. With clean balls you get no Toilet Bowl Effect. Even with the lightweight flybar. So there are four things that I know of that cause TBE; 1- Binding in the flybar caused by: 1a)Flash on the linkage balls (oh the jokes, but I'm not going there, or 2a)binding of the flybar center mount in the hub. Look for any nicks along the flybar plastic center that may catch on the sides of the hub. If the flybar gets a hard whack it will try to twist in the head. If you have the CNC head the plastic may get a nick in it which will bind against the side of the hub and cause all sorts of grief. A little sandpaper will remove the nick and make your life so much better. 2- Binding of the upper blades when mounted to the upper hub. ANY binding at all will cause TBE. 3- Bent flybar - that little bit of bend will become a whole bunch of bend when the rotor is at speed. That bend causes the pivot at the center of the flybar to bind in the hub. 4- A bent inner or outer shaft - the bent shaft causes the rotor head to spin in a circle, not just rotate and that pushes the flybar out of whack. But it looks just fine when you stop the rotors. It’s magic! Anyhow, it’s also causing TBE. Remove the blades top and bottom. Move the throttle to the right then forward to make just one shaft spin and look down at the hub from directly above. OK, now move the throttle to the left, then forward to turn the other shaft slowly and watch the rotor head. If either shaft is not spinning true, fix it or replace it. If the hub is not spinning true, it's causing the flybar to warp at higher rpm and that does the same thing as a bent flybar.

Flybars; Clack is Whack

So, now you are clacking blades. The blades clack because the flybar can actually INVERT the upper rotor blades! So when you command an aggressive forward move, the flybar pushes back with full force. The rear portion of your blades is lifting to get the heli nose down, and the upper rotor blades are pushing DOWN to counter the move until the upper and lower blades collide (clack) and explode.

There are longer shafts to move the rotor blades further apart. A lot of guys do that and if they are happy, good enough. I have my own method to combat clack. What I'm looking for is increased performance with very limited upgrades. As I started working toward a performance CX, I discovered some cool stuff. I'm no wizard, but I'm really curious and I like to think. I'm having a really good time with the results. Here’s the poop. When you get really good (or really bad) you will transition fast forward to full reverse- like when you are trying really hard to save your butt just before flying into something hard. At that point the lower rotor is tilted well forward and the upper rotor is (naturally) fighting you by tilting backward as far as it can. When you suddenly reverse the right stick, the lower rotor will suddenly tilt back and the upper rotor will react by tilting the opposite way and the upper . . . Man, this is getting too complicated. PUT ON EYE PROTECTION! Hold your heli in your hand and bring the throttle up until you feel the heli start to lift. Now gently move the heli so the nose points up then down, then up and down as you watch the blades from the side. Go easy – if you clack the blades, you can put an eye out. See how that flybar controls the upper blades? When the servos are forcing the lower blades to do as you command, the action really starts. And then there is clack. Got it?

The Clack of Death

The clack is from the upper rotor blades striking the lower blades. Because the upper and lower rotors are going opposite directions the leading edges of the blades hit each other (the clack part) and pretty much just blow up (the death part). Then the clack stops. Then the heli falls outa the sky. Then you go to the LHS. Then you trade money for new plastic parts. And straighten or replace the flybar. Then you explain to the next newbie what blade clack is. It really is that simple. And I suppose that you want a fix? It’s detailed below. I’ve included a flybar mod (CF MODBAR) that takes care of most of the aggravation provided by this little wonder. And others have their own method for controlling clack, but mine is cheaper. And it works for me. Among remedies that are documented as valid are longer shafts. I don't use them. Many do. Again, be happy. The shafts certainly won't affect anything but your budget and if they save blades they save money. Thats reasonable.

Got the Golly Wobbles?? Let’s get it straight

Golly Wobble - that's when the whole heli shakes like it's having a fit. It may fly that way, but c'mon - do you really want to do that to your heli? The first step for me when I had (have) these problems is to isolate the source. You have several places where the vibration can come from; flybar, upper rotor, lower rotor, outer shaft, inner shaft, upper tracking, bent blades. If anything listed is out of whack, it will wobble the shaft assembly which makes the flybar think it's out of balance (even if it's fine!). SO, try this;

First remove all of the blades and the flybar. We need to verify the shafts. When I get a bent shaft, I use this trick to isolate the two shafts so I can determine which shaft it is.

Move the throttle stick to the far right and then add a little throttle. That will run just the upper (inner) shaft. 
Move the stick to full left and add a little throttle to check the outer shaft.  Got it? So, how did you do? Shafts straight? 
I have a straightening section below. If the shafts are good, your head should spin up to about half rpm and show no wobble at all. 
No need to run it at full RPM because with the blades on, the rotors will never spin that fast. 

On the assumption that your shafts are good, drop the flybar into the hub on top. Fold the linkage over the top and stick it down with a little tape. You don't want that link to throw the balance off. Now spin up to about half throttle - just spin the inner shaft. OK? Now spin both of them. If you suddenly have a wobble that wasn't there with either single shaft, check to be sure your bearings are seated. I changed to the aluminum bearing cups and new bearings (it's a kit) and my heli got more steady. If your flybar caused the wobble, you know what to do. If not, remove the flybar and install the LOWER blades. Spin up the lower rotor. If you get wobble, you have out of balance blades or the pitch of one of the blades of goofy. Replace (DON'T Discard) the lower blades and try a again. We've seen blades that are balanced statically (with a scale or balance) but don't have the same pitch. If you get a shake out of the lower rotor, that will cause the entire inner / outer shaft assembly to wobble a bit. That throws the flybar off-center which makes the flybar hub spin off-center, which bends the flybar rods slightly and shakes the heli. But it looks fine when you look at it stopped.

OK, Let's assume that the lower rotor is spot-on. Remove the lower blades and install the upper blades. Do they move freely? Will they rotate when you pass your hand over them creating a little air movement? If not, fix it. If they move freely, spin up the upper rotor. How's the balance? No wobble? So we have verified both shafts, the lower blade pair (separate blades don't count - you only verify pairs), the upper blade pair, and the flybar. Now connect the flybar to the hub. Check the ball on the upper blade where the flybar link will connect. Is it perfectly smooth? Do you use needle nose pliers to push the ball through the loop on the link? If so, look for a burr from the pliers. The ball has to be perfectly smooth. Snap the link onto the ball. Everything is absolutely free and almost moves by itself, right? Now spin the upper rotor - Hang on. Let's see those safety glasses. You think you use a lot of blades now, try flying blind! OK, spin the upper rotor only - and spin it fast enough so it tries to lift the heli. Checking blade tracking at low RPM is worthless. Bad tracking shows when the blades have lift. Is your tracking right on? Hmmm, what have I missed? If it still shakes, look at the lower blades and spin them up - just the lowers, and put some power to it. Look at the tracking of the lower blades. Of it's off, it's the blades and they gotta be replaced. The lower rotor can suffer tracking issues, but there's not much you can do about it other than swap blades. Anyhow, if you keep swapping lower blades and one of the blades keeps showing in the reject pair, you got a dud. It happens. It's a buck. Deal with it. Or boil it in water. It may return to the correct form.

If you had a bent shaft from above, we need to straighten the bad shaft

If it's the outer one, I take the inner shaft out, spin just the outer shaft and very lightly touch it with a felt tip to make a mark on the 'high' side. Then I pull it out, support the shaft on the ends and thump it on the felt tip mark, and try it again. With your heli lying on its side, you don't have to assemble the heli to run the outer shaft. Just stick it through the bearings and engage the drive gear and run it again with the heli on its side. TIP: It takes a pretty good thump to bend the outer shaft. It takes very little to bend the inner shaft. Keep working at it and you’ll get it. I’ve straightened mine several times. The inner shaft is easy. You need a flat surface (table) so you can drop the flybar hub off the edge – then roll the shaft looking for the bend. Straighten it gently. It’s really soft rod. Or get a drill rod and make your own. Use a Dremmel and cut it to length and grind the little flats on it. The drill rod won’t bend and there’s no weight penalty. You want a 0.078 diameter rod. What’s that in fractions?? You, there in the back row asleep – yes YOU!! C’mon, divide 5 by 64. The calculator shows 0.078, thus .078 is a 5/64ths drill rod. And you thought you couldn’t do this.

Transmitter Mod – No More Thumb Cramps for Gramps

There was an article discussing the removal of the springs that hold the transmitter sticks on-center. The author recommends removing the springs. Do they actually help us poor stupid humans fly? I dunno. I do know that I fight them all the time. Maybe I wish they weren’t there at all. Hmmm. I'd sort of like something to center the sticks when I start up, but I guess that's just a crutch. With the adjustments made so far I can lift and hover touching only the throttle lever because the heli is tuned that closely to spot-on. I'm thinking that the spring thing is common with all controllers so we have a center reference point, but I can just tell by that little tingle in the nether regions of my brain that my springs are going to be removed. Hats off to the author, but then another post came along with more information. Take the back off of the transmitter. Note where the springs are fastened and note that the spring mounts are hooked to little tabs. And the tabs can be adjusted using the screws all bright and shiny. As you screw the screws, the spring relaxes. When you screw the screws all the way, there is just the slightest amount of pull from the springs. Just enough to let you know where the center is for the stick, but you don’t have to fight it. That’s where my transmitter is set. I’m happy. Happy is good. And about the throttle stick ratchet action. That ratchet is a real problem for heli pilots. My stable hover altitude is between two notches. The ratchet is fine for airplanes, but for the rest of us, there are three remedies. Pick one. Remove the back cover of the transmitter. Loosen the screw that holds the brass spring blade that makes the throttle all ratchety. That’s fix #1. But the screw is not tight. Maybe that’s not too good. While the screw is loose, use needle nose pliers and smush the jog in the end of the spring blade so it does not engage the teeth. Now tighten the screw. That’s #2. Or you can remove the spring blade and turn it over and re-install it. That’s #3. Pick one and tighten the screw and put the transmitter back together. Aggravation gone. Cost, nothing.

So, I fixed it ‘till it didn’t work anymore. And now it’s better

NO MORE BLADE CLACK. My 'fix' for the blade clack situation is to reduce the weight of the flybar. The lightweight flybar doesn't have the ability to counteract the lower rotor and stop the heli. It can slow it down, but it can't stop it. Others who “Fly it like they stole it” have told me that with my mods the blades WILL NOT CLACK. I never have had it happen. Hardly a guarantee, but it is compelling anecdotal evidence. And one of the readers has moved his link out one hole and he can't clack his either. I don't have the long center shaft or shaved blades or any other tricks. So, if we were having this conversation over the back fence, I'd hand you a beer and recommend that you try my mods to see where you are. The change to the response is fantastic - the lighter the flybar weight, the more responsive the heli. Indoors I fly with two collars on each end of the flybar on the bad days. When I feel brave or I'm outside, I have been down to just one collar on each end of the flybar. I've gone as far as just one collar on each side and it was midway between the hub and the end of the flybar rod. That's a handful and I'm a lousy pilot but I am certain that a better pilot could control it. It just wanted to dance and I couldn't keep up. I'm new to helis, but I've been thinking for a long time. I do what I do best.

THE MOD: If you are able to get a good hover, you don't need the stock flybar weight. Stick a tiny screwdriver or wire down between the brass weight and the rubber boot in the flybar end weight. Pop the brass thing out. Don't loose it. Try to hover with just the rubber boots on the end. If you're OK with it that way, you should see far less blade damage. Lighter Flybar = Less Clack. Then, if all goes well, get more serious. With the weights out of the rubber things, slide the rubbers up onto the flybar and cut the flybar ends off. A Dremmel works great for that. I did shorten my flybar rods to 3 3/8" (measuring just the exposed metal part). Slide the rubber things off the ends of the flybar rods. Go to the local hobby shop and get a set of locking collars. They are about 3/16 in diameter, about a quarter inch long with a hole in the center for a 1/16 inch wire. And they have a setscrew to lock them on. I started with two weights on each end and it flew just like stock, and looked way better IMHO. Then a couple of brain cells fired and I realized that I can defeat several of our enemies with one move and $4.

I purchased a length (24”) of Carbon Fiber Tube - .060 inside diameter x .125 outside diameter. The tube slips nicely over the flybar rod. On each end I have (1) of the collars noted above. That collar holds the carbon fiber tube on and it adds just a bit of weight to the end of the flybar. So what have I done? Well, the look is just what I wanted. Of course, you could use a little paint on the CF tube to get any look you want. If I use clear paint will the flybar become invisible?? The response is very good. The tendency of the heli to go 20 feet, then stop is virtually gone. With the flybar completely free of any drag at the pivot points there is NO TBE. If you do get crash contact, the carbon fiber won’t allow the flybar to bend. The carbon fiber also has very little mass, so there is remarkably little force to transmit into the head in the event of a crash. The good news is that there is a stress relief point where the carbon fiber touches the plastic balls at the middle of the flybar. A bend at that point is easy to see - and easy to fix. Because my flybar is so light, I don't think that it can force the blades to clack. The lighter the flybar the less it fights the heli. That seems to be a very good thing. The upper rotor accelerates more easily so flight is directionally more stable.

Technical Stuff:

Stock flybar weights are 2.4 grams EACH (rubber and brass insert combined). Collar =0.83 gram each. The carbon fiber rod is .217 grams per inch (.217 gm/ in X 3.187” = 0.69 gm per tube). So my mod removed 4.8 grams from the stock flybar. With the rods and collars in place I put back 3.04 grams for a 37% weight reduction. That sounds like a pittance, but look at the weight distribution. The old weights were 2.4 gm each - at the tips of the flybar! Now we have just .8 gm at the tip. The rest of the weight is distributed over the length of the flybar rod. And the flybar is a bit shorter.

Cool moves

Story Time: With the mods and tweaks in this sheet complete, I took the heli back to my LHS and asked the Senior Staff Heli Guru to fly it. A stock CX flies about 12 – 15 feet, then it stops and hovers. Mine flew as far as he cared to fly it, then he turned around and flew back. With my heli at hover in front of his face, he set the TX unit on the sales counter. My CX just hung motionless in the air until he reached out retrieved it with his hand. For the record, the heli that I am flying to do the moves described at the end of this uses a stock battery, stock motor, stock body (with the rear little horizontal wing removed). I have cut the body and the 4 in 1 case for ventilation and I have the aluminum motor heat sink and aluminum flybar hub / center shaft. I have the aluminum upper hub and aluminum bearing-cup that sits on the top of the outer shaft.

Here's something to test your ability

Outside, when you have a calm spell, try this. Hover the heli at a couple of feet off the ground with the nose pointed in the direction you want to go. Then shove the right stick and the throttle stick forward to the max and watch the little bird rip across the yard. The secret is to add a bunch of throttle when you push that right stick. The gyroscopic effect seems to be nullified when you change the rpm of the flybar / upper rotor. When you have gone far enough, bring BOTH sticks back to center - gently. Your heli should have gained about 20 feet of altitude for every hundred feet it flew away. If all is well, land the heli and shut down the power and let it sit for a few seconds to catch its breath - honestly, the battery will see a significant improvement even if you don't disconnect the battery connector. Now repeat the flight described above, and when it's out about 70 feet and 20 feet up, steer into a LEFT turn with the left (rudder) stick and she'll make a wonderful long arc turn-around. Bring the left stick (rudder) back to straight - then reduce the forward and throttle to mid-range. It's pretty dramatic and will make you look like a pro. And I think that part of the trick is to turn left while accelerating. It's a gyroscopic thing. I don't know that I've ever tried the same thing while turning right. Somebody go try it and let me know. NOTICE: If you get nervous as it takes off in fast-forward, don't just cut the throttle back or it will stick its nose into the dirt. And if you maintain full throttle and cut the forward stick it will go nose straight up, then fall out of the sky. Once you figure out the balance, you can hold the right stick full forward and control the altitude and direction with the throttle stick. REMEMBER - Left Stick =Throttle = Altitude (and direction the nose points); Right Stick =Pitch (direction the heli flies) & Ground Speed .

I've worked with this maneuver a bunch and the body on my poor heli shows it. More tape than plastic! I'll gladly accept any input from anyone else on this subject. I know what works for me and I'm still working on the performance aspects of this little heli with only minor revisions to the original design. Yesterday I did what I described above and I went into a long left rudder turn, then added too much left aileron (right stick) and I actually inverted the heli. I have the scratches on the top cover of the aluminum flybar holder to prove it. No, it was not a good landing, but it hit the flybar hub so perfectly inverted that it knocked the outer shaft collar (below the swashplate) out of adjustment and didn't break any blades!

We are reminded as a newbie, not to fly with any breeze. So we go inside and pretend like the significant breeze that the heli creates doesn't matter. It matters. And the longer you fly in a small space the worse it gets. I know that I can blow the leaves off my driveway with the CX from 10 feet in the air. There's more moving air created than I ever would have guessed. AND the air pattern matters. A consistent flow of air around the heli is not so bad, but when you get close to a wall the air pattern changes and the heli will go to the wall. Fly by a chair and the air pattern is again fouled up and you hit the chair. It's not you. Stay away from stuff. I find flying through doorways particularly vexing. Door on one side and wall on the other. Terrible airflow dynamics. A boom style tail does help.

SO . . . what’s next?

SO, you have this little bugger mastered. When are you ready for a single rotor heli? Ya got money ya don't want? Some adapt to the single rotor with no problem at all. Personally, I have a terrible time with them. The single rotor is not forgiving. You want the heli balanced and trimmed all proper or you better marry the banker's daughter. The CX hangs from a gyroscopically controlled upper rotor and it's stable. The CP sits on a column of air and it's inherently unstable. The smaller the heli the harder it is to fly. When you get good with the CP, you can fly anything. So, play with the flybar on the CX, try some of the good-looking mods in this forum. And when you just can't stand it any longer, get the CP. Or rather, get whatever your local hobby shop supports.

Best wishes to all, and to all a Good Night

Mark (aka Soloboss)