Axe CP separations and setup journal

[carloserizzo]

Hey Carlos, i think the t-rex is a little expensive for the project. Try with a Honey Bee King 2.
I'll try that model today "jueves" donde Demetrio, jejeje sorry for the spanish folks!


So, you will try that today jueves donde Demetrio... Pues Demetrio Zigras me ha dado clases a mi! La ultima fue hace como 3 semanas, pues empece clases y ando un poco ocupado ahora... De donde eres? Hace cuanto te iniciaste en el helimodelismo? Vas a la rosaleda?

[Ray K.]

markind-

I was just looking at the close-up photos of your tail rotor system, and have a suggestion for you. It may not be a big deal, but you may want to move your tail fin up the boom (toward the frame) by about 1/2". I've noticed in my experimentation that the tail prop seems to be unusually sensitive to aerodynamic "obstacles". BTW- what kind of connector do you have there on the tail motor? Slick!

-Ray

[carloserizzo]

Hey guys, here I am, again, needing BIG BIG HELP this time. Today I made one of my best hovering, remember I’m a newby. I was hovering for about 8 minutes and then saw a big spark and dark smoke, so I landed the heli and disconnected the battery immediately. Remember my setup: GY 240, C7 ESC for tail motor and 3 in 1 board for the main motor ESC (still with brushed main motor). After letting everything cool down, I started checking everything. The first thing I did was disconnect the main motor. Plug the battery and checked the receiver, everything looked fine, the servos were moving. Then, I apply full right stick and left stick, to arm the tail esc. Looks fine too, the tail motor moves and gyro seems to work. Then, I inspected the 3 in 1 board. Everything appeared to look fine in the trimmers side, but then I checked the other side and BIG SURPRISE, looked like a pizza after 3 hours in the oven. Everything was burned. As I was using just the main esc of the board, seems reasonable to think it burned out. At this point, the only electronic thing that came from stock need to be replaced. As I still have the brushed main motor, am think in buying the ELECTRIFLY C-25 BRUSHED ESC. The other option is spending a bit more and buy the brushless ESC and park 370 motor. If I do that, my axe will look pretty much like Ray’s (I do have the DD tail, but still haven’t done that modification), except for the receiver, because I still have the stock one. The only thing that stops me from buying the brushless main motor is that my LHS told me that I’ll have to upgrade to a brushless tail too.

Ray, at this point you should have flow your heli a lot, so based in your experience I want you to tell me if the GWS DD tail live is long? Have you replace any of it? If you haven’t have any problem with it, and if your DD tail motor life is “long” with the brushless main motor, then I will upgrade to brushless main.

The other problem I’m having is the connections. I’m inspecting my 3 in 1 esc and it connections. It has the battery cables to the board and three cables that connect to channel 3 of the receiver. Is the cable that connects with channel 3 powering the receiver? Because is the only cable that comes from the board to the receiver. So, if I buy an esc, the three cables from the esc should connect to channel 3?
The other thing that is confusing me is the orange wire, connected to channel 5 after following Helimax instructions to install gyro.

Does any of you have the stock receiver? I will modify Rays schematic (with your permission Ray) adapting it to my setup. Ray, can you please check it? Specially the rx channel connections.


Thanks a LOT. You guys have helped me a lot until know, and I think this wont be an exception.

[Ray K.]

Carlos-

I'm sorry about your 3-in-1, man! Your troubleshooting was exactly right, though. Your LHS, on the other hand, was not right. You can run a brushed tail with a brushless main motor just fine- that's how my ACP is set up right now.

You can do one of two things- you can go ahead and buy the ElectriFly C25 ESC, install it, and be on your way. OR, you can go ahead and upgrade to a BL main motor and ESC. There is no reason that you should have to upgrade your tail motor if you decide to go brushless. Either way will work- it just depends on how much performance you want and how much you're willing to spend. The BL system will give more power and longer flight times, but it will cost more.

As far as the GWS tail motor, I can't really say how long it will last. It's certainly at least as good as stock, and it's cheaper to replace. I've got about 5 hours of flight time on the GWS tail motor, and it's still working fine. It seems that the DD tail actually helps the tail motor- the DD system is more efficient, and the tail motor seems to run cooler with a direct-drive prop on it compared to the stock setup. I've been running that tail motor with a brushless main motor with absolutely no problems, and I wouldn't expect it to go any differently for you.

Now, for the connections to a stock Rx:

CH1- top rear servo
CH2- front servo
CH3- ESC
CH4- gyro
CH5- unused (but would be the orange wire if you still had the stock 3-in-1)
Ch6- bottom rear servo

I hope this was useful, Carlos, and let me know if there's anything else I can do to help you. Good luck!!!!

-Ray

[carloserizzo]

Thanks a lot Ray, again, for helping me so much. I think I will upgrade to brushless, seems the best choice. What's your flight time with your 1250 lipo? Because I have the 910 mAh lipo, so my flight time is going to be less than yours, but expect at least 8 minutes in the air. It will suck if I upgrade to brushless to be in the air just for about 5 minutes with this lipo. With the stock motor and the lipo, I have about 15 minutes of flight time.

[Ray K.]

Carlos-

I have my DX7's timer set to 11:00 with my 1250 mAh LiPos. I could easily fly safely for at least a few more minutes, because my charger indicates that I still have about 3.6v per cell left after 11 minutes. Since I removed the low-battery warning system, I just like to be sure I'm not hitting my batteries too hard. That, and I've been maneuvering the helicopter around quite a bit, trying to test the best tail setup. That takes a little extra power too. Even flying as I do, I'm still pretty confident I could safely get 14 minutes of flight time. That's not to say that there's anything wrong with the 910 packs- the 1250's that I've got actually turned out to be a little tough to mount, and made balancing the helicopter a little weird, too. I'd just stick with the 910 pack.

There's no way that upgrading your main motor to brushless will shorten your flight time! It actually *improves* your flight duration. Brushless motors are far more efficient than brushed motors, and take less battery to make more output than a brushed motor. They're also comparatively lighter than brushed motors, so the overall weight of the helicopter will come down too. I feel that the helicopter was easier to fly after I put the Park 370 in- the higher headspeed really smoothed out the heli. Cyclic inputs were actually crisp enough to really control the helicopter. You've made a good decision! There are plenty of BL ESCs out there to pick from, and many are around $35 or so. It's actually cheaper to upgrade to a Park 370 and a decent BL ESC than it is to simply replace the stock 3-in-1! So less money for less weight, longer flights, and more power? Sounds like a winner to me!

[Ray K.]

Okay, guys-

I just came back in from doing a couple test flights with the new ball-link swash link conversion. Overall, I have to say that this is a worthwhile mod, even if you're still using the stock radio. I was a little concerned that the unusual geometry on the links would have adverse effect on the swash, but there seems to be no interaction issues. I spent some time on the setup, and the swashplate stays level throughout the collective range. If I did have to adjust the EPA, is was only by like 4% or 5%- not really enough to matter. I think that it would work fine if you're still using a stock radio, and can be fine-tuned when you get a programmable radio. Once I got the blades tracked in, the helicopter felt almost as stable as my 'Rex- it appears that the deflection in the horns when you're using z-bend links is enough to dull the cyclic and collective response. In all honesty, these last two flights were the highest-performance flights the FrankenAxe has had yet. It was a little windy, so I can't tell if the heli drifts any more or less, but the control is certainly better.

While I was making the special links, I also made a special flybar locking tool out of extra parts. I used one of the links that came in the TRex link pack, and made a link that goes from the swash to the seesaw. This link is the exact length to keep the flybar locked to the swash- so if your swash is known to be level, the flybar will be level to it. This "setup link" was really useful when I was setting up the EPAs, and it also made setting up my pitch curves easier. Bonus!

I'll do a writeup very soon, and I'll be sure to have some good photos. For now, I'll tell you that all you need for the conversion is this stuff:

1 set of TRex 450 (any version) link balls and screws ($9)
1 set of TRex 450 (CDE version) links and link ends ($3)
2 sets of Axe CP swash and pitch links ($7)

I'm assuming that you're using HS-55 (or any servo with the same case) servos, and have the nice thick arms that came with them. The holes in the horns need to be up-sized to accept the ball screws, but I'll go over that in the writeup.

It seems like the simplest mods I've done have been the most effective. If HeliMax were only to give the stock Axe CP as you receive it out of the box some ball-link swash links, brushless power, and a direct drive tail, they would sell a million of them. None of these mods were especially expensive, either. I think maybe I should make a post about what the cheapest path to a really great Axe CP is....

I'll try to have that post up tomorrow evening. Until then...

-Ray

[Ray K.]

This is likely one of the best mods I've made to the helicopter. I had been concerned since I first got into the hobby that the stock Axe CP servo horns and z-bend links were making the helicopter difficult to fly. I quickly made some better horns, but continued to use the z-links. The heli flew a little better, but still felt "swishy" to me, and this was especially obvious after I flew several times with my TRex. So I started looking around for parts, and this is what I came up with- a relatively inexpensive way to convert the links to proper ball links.

You are going to need this stuff:

1 Align PN AGNH1326 - this is a bag of link rods and link ends for a TRex 450 CDE/XL. There are enough rods in this kit to make all the links we'll need and then some.

1 Align PN AGNH1127 - this is a bag of screws and balls that fit the link ends you just bought.

1 set of Helimax Axe CP swash and pitch links - you can salvage parts from your old links, but having an extra set or two of these is a good idea, and then you'll be able to build a cool flybar locking tool.

1 set of HS-55 servos (stock servos have the same case, so these are okay too) with a fresh set of horns - You're going to want to do this with the thickest horns you can get that fit your servos- the whole point of the mod is to reduce servo arm deflection!

Some horns will have to be drilled out to accept the ball screw, and this was the case on my new set of HS-55s (I had a crash that wiped out all my servos). I was able to drill the hole out up to 1/16" with a drill bit held with visegrips. I simply spun the horn around on the bit, and it worked perfectly. The screws fit just right- they hold tension well. So after selecting the horns that lined up best at center for each servo and drilling them out, I installed the ball on the case side of the horn. I don't know if DS285s or other servos will have clearance for a ball on the inside, so be sure to check.

I set those aside, and then began making the links. The easiest way to do it is to take the links off of the helicopter, and use them as length templates for the set that you're assembling. This is why I recommend having an extra set of HeliMax links handy- you'll be able to build a link and compare it directly to a link that came off of the helicopter. It no doubt saves a lot of time and frustration when you know your links will only require minor tweaks! It's also good to have extra pitch links laying around too- they're VERY helpful for blade tracking! I have 8 links in rotation, and they're all slightly different lengths. When you have a situation where your tracking is out, but one turn on the link is too much, just use a different link and check. It's allowed me to really fine-tune the tracking! Ready to spend $4 on extra links yet? Thought so.

It's a simple matter of choosing a rod that's an appropriate length, and putting an Axe CP link on one end, and a TRex link on the other end. The TRex rods have very fine pitch threads on them, so you'll also be able to achieve a finer degree of adjustment. The Axe CP link ends with the coarser threads actually cut new thread for themselves when you screw them onto the TRex rod, and hold firmly. You'll need two long ones and one short one. At this point, you can also make a flybar locking tool. Take one of the left over Align rods, and make a link that has 2 Axe ends on it. This rod will go from the swash to the seesaw, and should be adjusted in length so that when the swash is level, the flybar is level. You'll obviously have to disconnect a pitch link to use the tool, but if you use it on the side of the seesaw that's opposite of your master main blade, it makes setting up pitch curves and checking for unwanted swash interaction a much simpler process. If you're still using the stock radio, you may still want to make one anyway so you'll have it when you get a better radio.

It was actually a pretty quick little project- it's taking me much longer to tell you about than it was to do it! The links fit nicely and don't interfere with anything on the frame. The somewhat compromised geometry of the links really proved to be almost a non-issue. I checked the flatness on the swash all throughout the collective range, and it stayed 99% flat without any adjustment to the EPAs. I tuned my EPAs and got the swash to stay perfectly flat, but it only took about 4% or 5% adjustment to get it. I think the head design of the Axe is actually to credit there- it takes very little vertical movement of the swash to produce large changes in collective. There can't be any more than 10mm of movement for the whole collective range, and that means that it won't be very sensitive to mechanical interaction issues because the movements are so small.

I took the FrankenAxe out for the first test flight with the new link setup, and was immediately aware that the helicopter was way more controllable. Even with the tracking out, it had a much more direct feel to the cyclic than it had before. After adjusting the tracking and dropping in a fresh LiPo, it flew even better. I'd say that it handles more like the 'Rex than an Axe now. I trimmed it out and got it to hover hands-free, and it feels like it's finally got the control authority to fly out of mistakes instead of crashing. This is the best that the FrankenAxe has ever flown. I crashed it really badly about a month ago, and it's been grounded until yesterday. Since flying the 'Rex around so much lately, it just impressed me even more when the Axe was flying so well!

Check out the photos below for detail questions... a picture's worth 1000 words! The second photo is what your finished link should look like, and the other two are of the links installed on the helicopter. If you have any questions, just ask!

-Ray

[carloserizzo]

Hi Ray! REALLY interesting what you have wrote. The last thing I could ever imagined is that the z bends could cause that problem, and how important they are in the stability. Because of what you have wrote, and how you got excited with that improvement, I can’t wait to do that modification. I went today to my LHS and asked about the parts. They had the agnh1326, but didn’t have the agnh1127, so I’ll have to search that one on the web, but because of my location, it takes a little bit to receive the items. Meanwhile, have plenty of work to do. Today I received the brushless esc, DDTAIL motor and propellers. I’ll begin with that, then install the brushless motor and finally the linkage mod. One more question, where did you get that servo horns? Do they fit in the stock motors? I asked about HS55 horns at the store today but they didn’t have any micro servo horns :S.

Thanks!!!

[carloserizzo]

About the servo horns: I found two that seems strong. They are supposed to fit in the HS-55. The first one PN EFLRS754, and the second one EFLRS753. Do you still have the stock servos around? Does the HS55 horns fit in the stock servos? If yes, wich one of this horns would you recommend? Or the axe cp weird servo arms (PN HMXE8818) are strong enough? Because they seems weak to me.

http://www.readyheli.com/E_FLITE_3D_Arm_Set_p/eflrs754.htm

http://www.readyheli.com/E_FLITE_Standard_Arm_Set_with_Screws_S75_HS_55_p/eflrs753.htm

[Ray K.]

Carlos-

Unfortunately, HS-55 horns will not fit the stock Axe servos. I think that Du-Bro makes some horns that will fit the stock servos, but I've never used them. I'm assuming that you're still using the stock servos... have you had any issues with them twitching? That's why I was forced to replace mine. They were twitching, they didn't center up very well, and I cracked an ear off of one of them in a crash. I've been using HS-55s ever since; I think I only had the stock servos for about 2 weeks.

I know for a fact that there are other horns out there that will fit the stock servos... I'm just not sure what brand or style they take. As long as they're even just a little thicker than the stock horns, they'll be better. The other option, of course, is to simply upgrade to HS-55s. They're cheaper to replace, easier to get, faster and stronger than stock, and fit perfectly. Most hobby shops should have them for about $13 or $14 a piece, and you'll need 3 of them. It's not a good idea to mix and match types of servos, so be sure to do a full set instead of just one or two.

-Ray

[Major Bladebreaker]

Ho Guys!

I've tried to read through most of the 19 pages of this post in an effort to make sure I don't ask a question that has already been answered. I didn't get through all of them so I may slow you guys down anyway. First, I bough my stock Axe originally while in Iraq about 7 mos ago (I'm back home now) in order to have something to do off-duty. I own a "hybrid" Trex which consists of an HDX 450 G10 frame and a Microheli haed and tail. The thing flies like a Cadillac compared to the stock Axe but I didn't want to bring it to Iraq as I was concerned the dust would kill it. Hence the Axe for $200 bucks...
I was a rank beginner at the time but have mastered nose-in hovering since (mostly on the Trex though...). I was turned on to the Axe by an Apache pilot who had one in theater and flew it in his spare time. Since then, I have put most of a microheli head assembly on mine (huge difference in performace!) but continue to be plagued by all sorts of electronics problems which I'd like to talk about. I was thinking about cutting my losses at one point, getting rid of it and upgrading to an HDX300 but given that I already have an excellent heli, I'm having a hard time justifying the cost. Meanwhile, the Axe flies quite well when it happens to be working and it is very durable so for now at least I plan to keep it.
Recently, my e-board blew up (literally started smoking and sputtering) and I bought a GY 240. I had a CC Griffin 40 and a C-10 lying around so I followed the instrucions in this post and wired the thing up appropriately. It flew fine for a while but again started smoking after a few minutes. It turned out I had burned out the main motor this time. I threw in a old speed 400 and noticed that after a few minutes the thing slowed down as if out of battery juice and stopped altogether ( I have several 1350 Mah Lipo's and I figured there was no way they could be the problem). Anyway, the Griffin has a prop brake that you can't turn off and so I figure it has something to do with this. Also, I notice that when I turn the main rotors, the servos start to move (no battery connected) so the motor has turned into a generator. Is this the fault of the electronic brake system?...or did I not wire properly?...or something else?
Meanwhile, I'm seriously looking at going brushless. A few questions on that note based on my reading of this thread:
1) Is it possible to use the stock tail rotor system with the brushless tail motor or is DD just that
much more efficient?
2) I'm looking at a Hacker A206XL for the main motor. Any thoughts/cheaper but decent quality
alternatives while staying under 4100Kv?
3) What about an ammo 12-30-4110 for the tail motor vs the 3800 Kv version? Thanks in advance for
your help!!

Mark

[Major Bladebreaker]

Folks,

Just a quick update to my last e-mail, kind of embarassing actually. The moving servo issue, I discovered upon closer inspection, was being caused by a loose screw at the seesaw that was binding and pushing the swash to one side as a result (should have used more loctite...). Not a ghost in the machine as I had at first thought.... I hovered it for a while, though, and noticed the same problem with the motor bogging down (batteries are fully charged). I'm guessing my speed 400 is just not capable of handling 11.1 volts. Is there another explanation? Anyway, thanks!

Mark

[Ray K.]

Hi Mark!

First of all, I'd like to urge you to stay with a brushed tail motor. I'm not saying that the BL tail didn't work, it just didn't meet my expectations- I was routinely (and very easily) out-flying the tail. It couldn't keep up with hard collective changes, and seemed to oscillate before settling in. So far, the most successful tail that I've had on my Axe is a stock (or similar) tail motor with a DD prop. The DD tail is much better than the stock tail, and I'm having a hard time imagining why HMX thought it was a good idea to use the tail that they did- it's not as good and it's more expensive. Weird.

Now, for your gremlins in the ESC.... I wish I knew what to tell you, man! I think you're onto it with the over-voltage idea though. Either that, or you've got a bad brush in the main motor that's causing excessive resistance as it warms up, and it's causing the ESC to shut down as a fail-safe. I dunno.

For the main motor, I'm not sure about that Hacker. I'm not positive if it will mount directly to the fuse or not, but that's an easy problem to fix. The bigger issue is that it may not fit inside the frames, and it's probably way too much motor for an Axe anyway. If you want to build a muscle-chopper, I wouldn't go any bigger than a Park 400. If you're looking to stay below 4100 kV, I'm almost positive that there's a 3800-ish kV version of the Park 370, and that will run you about $50. It's probably also worth looking into the Great Planes Ammo series of motors. They're reasonably priced, and I've been pretty happy with everything that I've got from Great Planes (ESCs, motors, LiPos...). That said, my Park 370 has been plenty powerful for the FrankenAxe, and I've been very pleased with it. If the FrankenAxe had longer blades, I'm sure it would still have the power to pop like the TRex does.

I'm using a CC T-Bird 18 for my main BL motor (Park 370 4100 kV, 12T). I'd give it a 7 out of 10. It's cheap, and it works well enough, but it lacks the programming features that I've learned to love on my 'Rex's ESC. I'm looking into upgrading to a CC Phoenix 10 pretty soon. It's a little more expensive, but it's smaller, lighter, and programmable. Unfortunately, brushless ESCs for motors that only pull 9A are not very popular, and there are only limited choices. And they all cost the same as 35A controllers. Bummer.

Anyway, let me know if there's anything else I can help you with!

-Ray

[Major Bladebreaker]

Ray,

So a brushed tail motor, huh? Should I use that GWS prop you reference? Also, does it work better inverted like you did with the ammo brushless?
BTW, check out the following:
This is a CNC tail motor mount I'm going to try out. It's designed for the Blade CP but I think it will fit the Axe. It's only 8 bucks so I don't mind if it doesn't work out and the OEM plastic part is extremely flimsy:

http://www.helidirect.com/product_info.php?cPath=65&products_id=4553

I'm sorry I don't know how to cut and paste URLs properly so you'll have to cut and paste this into your browser...

Also, you might want to try out these blades. I have a pair and they do make a difference on the AXE:

http://www.helidirect.com/product_info.php?cPath=65&products_id=2142

Helidirect is a good company to deal with: their customer service tends to be excellent but they do make mistakes in shipping occasionally. They always more than make up for it, though.

Anyway, I think you're right, the A20 6xl is overkill for this heli. I'm looking at the A20 22L or a himax 2015-4100 (4100kv) or 2025-4200 (4200kv). The price is right on these and they're Himax. Anyway, thanks for the help and I'll talk to you soon about the results on my Axe. Thanks!!

Mark

[Ray K.]

Mark-

Yes, I'd definitely go with the GWS scimitar prop- I've had the best results with that one. When I swapped back to a brushed tail motor, I returned the tail prop to the original side of the boom, and it works fine. I'm almost certain that it would work fine flipped over too, so it's up to you. For the tail motor itself, I used a GWS EDP-50XC from allerc.com. It cost about $10, and it's virtually identical to the stock HMX tail motor, just without a pinion pressed onto it. Perfect!

Those blades look like they're pretty close... they have a narrower chord, and they're 5mm longer. The root is 5mm, and the stock ACP blades have a 4.5mm root... I hope that's not too much of a difference. $22 for some CF blades is hard to argue with though!!!

Talk to ya later...

-Ray

[carloserizzo]

Ray! I have been kind of disconnected from helis lately, college is driving me crazy this semester. Since my e board of my axe burned out, I havent been able to fly again. I bought the brushless esc but havent found the 370 park motor yet.

I write you this time because my brother is fliying to the States next week, and I would like to take advantage of that and buy the stuffs I need through him. Aside from buying the motor, I want to buy a better heli, thinking in when I get better. I was thinking about a TREX, everyone has recommended that. I want to buy the trex 450 sa because of the price, I'm a student and cant afford the SE version yet. The problem is my LHS (I have only one near my home) only sells parts for the SE version. I have read the main difference between the sa and se version is the material (plastic vs CNC), so, if I broke the blade grips of my sa, for example, can I replace them with the se version with no problem? Or are there parts that fits only in the sa or se version only?

Thanks

[Ray K.]

Carlos-

I've been trying to figure that out too. I bought my SA (and love it!) with the intention of slowly converting it into an SE as I became a better pilot. I've been having a hard time getting straight answers from people, but it seems that most, if not all, of the SA's and SE's parts are interchangeable. I think that if there are any compatibility issues, they probably won't be major ones. That's all kind of beside the point anyway- the TREX flies so nicely compared to the Axe that I still have yet to crash it after about 50 flights- it's that controllable. Parts availability was an important factor in my decision to get the SA over a MiniTitan- I have much better access to repair parts for the 'Rex. That's kind of turned out to not be an issue, though, because I haven't needed replacement parts... yet. I've really enjoyed my SA, and I think that it's a sound investment... that's why I chose it! I'm sure you'll love it if (and when!!!) you get one.

-Ray

[carloserizzo]

Thanks Ray! Other thing, I'm thinking in buying the dx6 transmitter, because the dx7 is too expensive to me and can't take advantage of those servos that came with the combo, so buying an extra set of servos will raise the total cost. With the dx6, are all the channels going to be used? I read somewhere that you use all of the channels because you can control the gyro gain with one channel. Is that possible? My setup will probably be:

Trex 450 sa ARF (with motor, esc), DX6(and use the servos and transmitter that came with the combo), a 2100 mah lipo and the gy240 from my axe. Is that all I need? Can I set my gy240 gain with the trasmitter? because all the combos I have seen has a gy401, dont know the exact reason.

[Ray K.]

I'm going to try do dissuade you from buying a DX6. Don't get me wrong- there is nothing wrong with it, and it's a great radio. Great as it is, a DX7 is a radio that you can grow into, and the DX6 will leave you with an inferior radio as you become a better pilot.

I'm going to tell you a story...

When I was about 14 years old, I was very much into RC monster trucks and stadium trucks. I had a ClodZilla (1st generation aluminum frame) upgraded so heavily that I spent about $800 in ups for it, even when the kit only cost about $200. I also had a (at the time) brand-new Losi LXT, and I had a Novak Rooster with Reverse (at the time new on the market) ESC. My trucks were state-of-the-art. The mistake I made was on my radio- I bought the cheapest Futaba 2-channel radio I could find. It was like $75, and offered no customization options other than gimbal trim. I hated it. I'm sure it cost me races.

Fast forward 14 years to today, and I find myself wanting to get back into RC, except I want to fly helicopters this time. When I decided that I wanted to take the Axe to the next level of performance, I knew that a good computer radio was going to be half the battle, somewhat based on my experience with my trucks. I was looking at the DX6 because it is very affordable, and it offered most of the options that I wanted. Then I started looking at stretching to get a DX7, and I discovered that I could get a combo package from an online vendor that included a Heli DX7, a Spektrum AR6100 Rx, and 3 JR DS285 digital servos for $310 USD delivered. For the capability that the DX7 has for the cost, it was an amazing deal because I could use all of the parts in the combo on the Axe- they were perfect for the Axe, even.

I'm so glad I got a DX7. It's got enough features to keep me satisfied for many years, I'm sure. There's a good chance that it's the only radio I'll ever need. When I bought the TRex, it was a simple matter of putting the servos on the 'Rex and buying a new receiver, gyro and tail servo. I think I got my TRex airborne for something like $700, including batteries. I saved some time and money because I already had a radio that could support a more sophisticated helicopter. That, and I knew that flying the Axe with the DX7 would make it easier to fly.

In the end, I had to be diligent about saving money for a DX7, but it was worth every penny. It was an investment in my RC Helicopter future. If you're still going to do that project with your school involving that model helicopter, then you might be able to convince the school to help pay for a DX7 that you'll own. The stock radio that comes with the Axe is junk- it's probably the helicopter's biggest problem. It works well enough to get you flying, but it doesn't offer any way to tune the way that the helicopter is going to respond to stick movements. Every pilot is going to learn to fly differently, so if that pilot can tune the radio to his liking, it stands to reason that he'll be a better pilot for it.

I guess that's the spirit behind this entire thread:

The HeliMax Axe CP is fundamentally a great helicopter. It's inexpensive, it's easy to modify, it's tough as nails, and most importantly, it's relatively cheap to modify. That said, it has some serious problems from the factory. It needs LiPo. It needs a better stock radio curve program. It needs to be easier to fly. If you're willing to spend a few bucks, an Axe CP can be made into a very nice little helicopter. Flying my 'Rex has made me a build a better Axe, and flying the Axe has made me a better TRex pilot. It's worth the investment. Just don't upgrade with HeliMax parts!!!

Now, I'm thrilled that I opted for the DX7. I can fly any helicopter I want with it. If I wanted to build a scale heli (I've been thinking of a Hind-D gunship....), I have enough radio to control retractable gear, moving elevator, and even nav lights if I wanted to. At the same time, it lets me fine-tune hard 3D machines so that I can truly have very good control over them. I'm sure that I'll be into the hobby for many years to come, and spending $300 on a great radio that I'll probably never outgrow made sense.

Now, if you want to just put your GY240 on the 'Rex, go right ahead. Many people fly TRex's with 240's and they have no complaints. The reason that I went with a GY401 for my 'Rex was because I wanted to be able to change my gyro gain from the radio, and only the 401 can do it. The GY240 works great on my Axe, and I didn't want to take it off, so I just got the 401 for the 'Rex and called it good. The GY240 is no doubt a very good gyro, but it lacks the adjustment and control features that I wanted for my 'Rex. It only cost about $20 more than a 240, so I did it. If you get a DX6, you may not be able to make full use of a GY401. So if you're certain that you want to get a DX6, be sure you have a GY240 for the 'Rex.

But.... Sooner or later, you'll desire a better radio than a DX6.

I hope I helped!

-Ray

[carloserizzo]

Hey Ray! You seems to love your dx7. You conviced me to buy it, but I dont have the money yet, I can't afford it. I guess I'll have to wait a little until I can buy it, or by the moments I will have to buy the dx6. The LHS told me that the main difference between them was the power: dx6 is for park fliers, and dx7 is a proffessional radio. By the moments I dont need a professional radio. I know that if I spend a little more and buy the dx7, I wont have to change my radio in the near future. But in my country is difficult to find spectrum radios and everyone is crazy for them, so I think I'll buy the dx6, and then will sell it to buy the dx7.

I started reading post about the setup I want: trex 450 sa and dx6 radio. Some people seems to have glitching problems, but then they realized it was a cutout problem because of the bad align esc. Can you tell me if you have had any problems with your trex?

[Ray K.]

Carlos-

My TRex has been AWESOME!!! I love it! I had a chance to fly yesterday- probably the last chance before the weather gets too bad- and I flipped the TRex inverted for the first time. It was very brief, but I did manage about a 5-second hover before I decided to flip it back over. That's how good it is- I've only been flying since last April, and the TRex gives me enough confidence to fly like that. It's got enough power and control authority to fly out of trouble. Once you get your basic skills on an Axe, a TRex is a very comfortable helicopter to fly. I haven't had any problems at all with it, other than just basic maintenance stuff like tightening the tail belt. The hardest thing about learning to fly it was getting over the intimidation of it, and learning how to deal with much more powerful collective response. The cyclic and tail control is very precise compared to an Axe. Everything about it is better. I've flown it probably 50 times in the last 2 months, and have not crashed it or had any problems with it. It's great!

I still love my Axe, though. I crashed her pretty hard yesterday, though, so the Axe is all done for the season. I think over the winter I'm going to put the full metal head from MicroHeli on, except for the blade grips (I want to keep those plastic). I've been so happy with the MH swash that I have a hard time believing that the other head parts are bad. I've also been considering going to a Park 400 motor and a CC Phoenix 25 ESC. And some carbon blades. I don't know if the rebuild during the off-season is going to include a new frame or not, but the FrankenAxe will definitely be a different machine in the Spring. We'll see.

That idea of selling the DX6 to help pay for a DX7 is a good one. I say do it!

-Ray

[carloserizzo]

Another question Ray. You have the REFLEX sim, but I think it comes with no controls, maybe the USB interface. What control do you use for the sim? can you use the spectrum? I wrote helimax people to find out if I can use the stock radio with usb interface for the sim, but the told me that for some reason, the stock radio doesn't work with any usb interface.

[Ray K.]

Carlos-

I have Reflex set up so that I can use my DX7 as the controller; you'll need the USB cable intended for JR-style radios. I can't remember very clearly, but I think that there is a controller available for the sim so that you won't have to use your own radio. Personally, I wanted to use my DX7 as the controller so that I could get used to how it feels in my hands.

I'm pretty sure that the stock Axe CP radio will not work with Reflex. In order to get the radio to work correctly on the sim, you must have the ability to send a mechanical swash mix signal, and the stock ACP radio transmits a CCPM signal. With the DX7, however, it's a simple matter of making a model on the radio specifically intended for the simulator. I'm pretty sure that a DX6 will work perfectly on Reflex.

Speaking of DX6, you are looking at the DX6i, aren't you? It's better than the original DX6, but still costs less than the DX7.

-Ray

[carloserizzo]

I first know about the dx6i when looking at the blade 400. In fact, I was thinking about buying the blade 400 just because of the control. Looks like a great deal, seems like an heli between the axe cp and a trex (or maybe bigger axe but with a belt tail system, which will save us a lot of money and complications), and that control will work for other helis. But then I think that a chaper heli will bring me more problems, and decided to go for the trex.

The main problem is that I have to bring all that stuffs through a courier, and deppendind in how much time does he takes to deliver the stuffs, I will go for the dx6 or dx6 i. I would like to receive all of the items by early december, to build it and enjoy it during christmas.