Axe CP separations and setup journal

[carloserizzo]

Hi Ray, thank you for the post. After reading, I have a question: if I move to direct drive tail motor, what other modifications do I have to do to the heli? Because the tail has to move 6 times slower than if it has the gear so that the speed of the proppeller would be the same. who controls that? the gyro adjust that automatically? or do I need to do other modifications, like programming a transmitter like yours (which I dont have, still with the stock radio). So, can I just move to direct drive tail motor with no major modifications?

The other question is: have you tried if that motor fits in the axe tail mount? because I checked out that motor on towerhobbies and it has the same diameter as the axe motor, so, it could be a cheapper replacement for that motor keeping the gear drive system.

Last, what is the main difference between direct drive and geared drive, in fliying terms. Is it easier? faster?

Thanks.

[Ray K.]

Carlos-

When Axes and Blades are converted to run direct drive tails, a much smaller tail prop is used. Since the direct drive prop is spinning much faster than the stock prop, it also uses a less aggressive pitch than the stock prop. With these two factors combined, it ends up making about the same or a little more thrust than the stock setup. The advantage offered by going to direct drive is that the tail is able to respond to rudder and gyro inputs with more precision, because as I noted earlier, the prop is able to accelerate and decelerate about 6 times faster than stock. It offers a more locked-in tail with better response and more power. I can't imagine why this setup isn't used in stock form- it works better, it uses fewer parts, and there is actually less chance of hitting the prop on the ground because of the smaller diameter. Even if you do hit the prop, it's really cheap to replace it- I got the props for about $4 for 6 of them. It does make a little more noise, though.

The tail motor is still controlled by an ESC, which is controlled by the gyro- sort of. Basically, what happens is this: With no rudder input from the transmitter, the gyro will sense and correct any unwanted yaw by automatically adding or removing throttle from the tail motor via the ESC. When you send a rudder command, the gyro gets that information from the receiver, and adjusts the throttle signal to the ESC to develop the desired tail movement. This happens with the stock electronics AND separated electronics- the two systems use different hardware to get the job done, but that's the fundamental principle. The gyro will simply add throttle as necessary to give neutral yaw. Think of a gyro as a "tail governor", and you're on the right track. It doesn't really care if it's telling a servo or a speed controller what to do- it just sends an appropriate signal to keep the tail in check, and does that automatically.

As far as modifications to the helicopter, it depends on what motor you're going to use. At any rate, no modification is major. The reason that I went to the Blade CP Pro tail case was because the Axe tail case has kind of a funny shape, and would have caused the tail prop to hit the tail case. The BCPP tail case is totally flat on the prop side, and allowed the prop to spin without hitting anything. The reason that I said it depends on the motor is because the motor I used has a short output shaft, and the BCCP tail case was the only way I could mount the motor and get sufficient shaft penetration into the prop- there simply would have been too little engagement with the ACP tail case. On the other hand, the brushless motor that I was fooling around with had a pretty long output shaft- I was able to use that motor with the ACP tail case and still have sufficient shaft depth. As for the stock ACP tail motor, you'll have to pull the pinion off, but it looks like that shaft will be long enough to use with the ACP tail case. It all comes down to being sure that the prop is pressed onto the motor shaft far enough, and without interfering with the mount or tailboom. The GWS motor that I'm using fits the ACP tail case perfectly, but the shaft doesn't stick out far enough- that's all.

In your situation, the stock radio will work fine with a DD tail. Once you get the motor that you'd like to use, test fit it to the tail case and see if you can get the prop pressed on without hitting the tail case. If it hits, just do what I did and get a BCPP tail case and modify it the way I did. It took about 3 minutes with a Dremel tool to get it done, and it's been working perfectly so far. I've found that having the motor shaft about half way through the prop is enough, but I wouldn't try it with less than that. Like I said, it just depends on the length of the output shaft on the motor that you choose. It's easy either way, and definitely a worthwhile upgrade- you'll be much happier with the tail's performance.

Hope this helped... let me know if you have any questions!

-Ray

[markind]

Kewl! I am picking up my BCPP tail case today. I should be able to get my BLDD tail running tomorrow.

In other news, I got all the parts for my Hangar 9 F22 Raptor PTS this weekend and got about half the assembly done already. Too sick... TREX needs final tail and rotor head mechanical fine tuning, and it will be ready for Maiden, perhaps next week...

[carloserizzo]

Hey Ray, thanks again for the reply, very usefull. I think I'm moving to DD tail, but still am waiting my GY240 to arrive home. I checked again the gws motor you mentioned, and saw that its a 6-7.2 v motor, but our battery is 11.1 v. Can't the motor get fried? Is it going to last longer or would it fried in few days like the axe's stock motor?

[markind]

Well looks like good news and bad news.

Good news is that I put an e-Flite 20mm heat sink on the tail motor and modified the stock Axe heat sink to fit in the remaining exposed motor area, thus maximizing the cooling potential.

The bad news is that I seem to have modified the wrong tail case. It is the same diameter as the Axe tail boom. I guess that is the difference between the Blade CP tail case and the Blade CP Pro tail case.

Darn. :mad:

[markind]

Hold on, I'm confused now. My LHS says the BCP tail part and the BCP Pro tail part is the same... what is different? How do I fit it to the Axe? :confused:

Edit: Ah, figured it out. You have to pull the little aluminum bit out of the stock Axe tail case first, then that allows you to mount the BCP tail case on the Axe tail boom, with the help of some epoxy.

Got it! Proceeding with re-wiring (again)...


Edit: Ok, almost there. I got new wires, soldered up a 3-pin Dean's connector near the ESC, ran the wires through the tail boom and out through the new tail case, and just now expoxied up the aluminum bit. Next step is to either solder directly to the tail motor wires or rig another connector... I'd prefer a connector, that should make it easier to change the tail if needed in future.

[carloserizzo]

Hey guys, I was reading some heli magazines and have a couple questions. I am a newby newby on helis, and have a lot of it.

Revo mixing happens in the transmitter? In the axe cp, it happens in the transmitter or in the 3 in 1 board? Because I was reading that when you have a heading hold gyro, like the one I'm going to install this tuesday, you have to turn off the revo mixing. So, how can I do that if the transmitter is not programmable?

I still have the brushed main motor and will use the main motor ESC from the board, but also will install the gyro and brushed ESC for the tail motor, and not use that part of the board. So, if the revo mixing happens in that board, I'll have no problems, but if it happens in the transmitter, how can I do?

Have anyone of you run this setup?

In a near future, I will upgrade to DD tail, and hope this work great with Rays advices (I dont know if it will work that great with the brushed main motor, but in the future I think that a brushless motor would be necesary). Running this setup, does anyone of you have an advice for me?

Any comments would be apreciate

[markind]

Carlos the Revo mixing, even if there is some in the radio, which I doubt, would not be enough to mess you up, unless you are a pro 3d pilot, and if so, you wouldn't be flying an Axe.

So, just go for it! Remember after any major mod, treat the heli like it is an all-new, totally unknown experimental aircraft, and take appropriate precautions.

On my side,

Bummer... I messed up my Ammo 3850. I broke the hair-like wires inside the thing. I'll have to get another one... :bawl


In other news:

My TREX project is on hold. But I did manage to get the tail just right and got the limits set properly.

I am about halfway through my new Hangar 9 F-22 Raptor PTS ARF build. I tried to start the Evo .52 engine yesterday, but no luck. I will try it again tonight, this time with the 15%nitro fuel (tried it first with the 10%).

[Ray K.]

Carlos-

You're looking to do exactly what I did on my Axe, and it works fine. The deal with revo mixing is that the radio gear will automatically add in (or take away) some rudder to help keep the tail stable during collective pitch / throttle changes. When you step up to a HH gyro, revo mixing is no longer necessary because the gyro is doing that part for you. Revo mixing is really only necessary with a bad rate gyro. As far as I've been able to figure, the revo mixing happens in the 3-in-1 board and not in the transmitter. It worked very well on my Axe, and I don't expect you'll have any problems.

As far as a DD tail with the stock motor, you should have absolutely superior tail performance. The brushed / DD tail on my bird with the BL main motor spinning the head at 3000 rpm keeps up extremely well, and I can only imagine that it will work beautifully with the stock motor.

markind-

Aren't those 3850 wires tiny!?!?! I couldn't believe how small they are! Sorry you messed 'em up though... Did you happen to make any more progress with the BLDD tail? I'm still trying to figure out what the theoretical ideal setup is. I'd try to get that 'Rex airborne ASAP- you'll LOVE it!!!

Later....

-Ray

[markind]

Hi Ray!

Yep, those wires are tiny. AND they are coated with an insulating varnish which much be scraped or melted off before any solder will bond enough to make a connection.

Belive it or not, I got into the little bugger and re-soldered my broken wires. But, after re-assembly the motor does not spin. Probably, I reconnected the wires improperly. I may go in again to try to fix it, when I have time. I have some time in the mornings to dink with the Axe, while I wait for more fun stuff from Tower. If I fix it, I will keep it as a spare.

The trick is to use a hot soldering iron with a tiny, pencil point tip. Your dollar store irons can not do it. Before soldering, I get in with a lit magnifier and scrape / clean / tin the wires with tweezers, Xacto, and the soldering iron. With patience, the solder will eventually bond to the wires, and a repair connection can be made.

On my next Ammo 3850, I will strengthen and bond the strain relief with epoxy. That would have saved my wires, had I known the strain relief was weak...

But I still got hobby fever, and tonight I install and test the tail, rudder, elevator of my new F-22 PTS. My son and I got the engine running! Its a screamer, but what a nice, slow, calm and quiet idle it has.

[carloserizzo]

Thanks a lot for the help, Ray and Markind.

I was looking for information about the GWS CN12-RXC DD motor. In towerhobbies page, it says it's a 6-7.2 v motor, so I was worried, because my battery its a 11.1v (finally, I got the lipo). In gws says the same information, but then I found this page ( http://www.gwsus.com/english/product/powersystem/edf40.htm ). This fan uses the CN12-RXC motor, and the information they gave in that page is that the CN12-RLC is the 6-7.2 v motor, and the CN12-RXC its a 12v motor, so I think we should have no problems.

About my tail problem, I can't find out exactly what's going on. I followed Ray's advice, disconnected the tail motor from the board and apply some voltage, and guess what? The motor worked. Then, I reconnected it to the board, apply some throttle and the motor worked, sounding strangly, but it worked. Two minutes after that, the motor stopped again. I think the motor AND the board have problems. When I install my gyro, will replace the motor too (fortunately, I have one stock motor replacement). Hope this worked and the problem didn't affect the main motor ESC.

When I was doing some test, I disconnected the main motor and put a voltmeter in there. Applied some throttle and the reading was 0, and in some point it jumped to 12v. I think it has problems too, but then I reconnected the main motor, add some throttle and the speed was increasing accordingly to the inputs. So i think the problem on the readings is maybe that it has no load when i tested it.

[carloserizzo]

Hey Ray, need a little help here, is going to take you 2 minutes. I finally got my gyro and c7 esc today. I was fisicly inspecting my c7 esc and something alarmed me A LOT. I looked the esc in the non label side and saw a tiny chip, MICROCHIP brand. Clearly, two consecutives legs are soldered, and it seems like a fabric mistake to me. Can you (or everyone that has a c7 esc) look yours and tell me if those legs are soldered?

Thanks a lot

[Ray K.]

Carlos-

Mine appears to have the same solder bridge, and it works fine. Try it out- it must be designed like that.

-Ray

[markind]

I got my replacement Ammo 3850 today. I should be able to install and test next week.

[markind]

Alrighty then,

We got the tail re-built, this time being more careful with the Ammo 3805's wires and not cutting them so short.

Confirmed! The GWS 3.5 x 2 organge plastic propellor is fine with just a push-on installation. No glue necessary.

Notice! For the motor / prop to work with this orientation, the tail prop will be spinning down and with the main rotor wash. On a TREX and full scale helis, the tail prop spins up and against the main rotor wash for better control as this increases the airflow over the tail prop blades.

However, the tail prop is small and the new tail case moves it slightly further away from the main rotor such that the tail prop is pretty much out of the reach of the main rotor downwash.

All she needs now is wire cleanup and tie-wraps and she's ready for another Maiden Hover Test. heh.

[markind]

IT WORKS!!

After a few tries, we got her up into a stable hover, in a very confined space. That's all I can do today, after getting the wires all neatly tie wrapped again.

At one point though, the tail ESC just stopped working. I was just sliding on the floor at the time, and when she started just spinning with a dead tail, I figured something failed.

But, I just unplugged the battery, and plugged it back in again to re-initialize everything. No probs after that.

Hmm, Gyro or tail ESC glitch? I hope it doesn't happen again!

Next step: Hover trials in a larger indoor space - my park's Clubhouse. heheh

[Ray K.]

Hi guys.

I lost my job today.

What this means is that I will no longer have all that fancy data acquisition equipment available to me. It also means that it will be some time before I can get back into modifying it, and even repairing it at this point will be a strain. Sucks.

The good news is that I found a GREAT way to do a ball-link conversion for the swash links. All you need are some TRex 450 CDE links, and some ball ends to go with them. I got all the parts I need at my LHS for like $12, and it just so happens that 3 of the links in the set will be the perfect length. So it can be done, and relatively inexpensively too. I intend on putting the servo ball on the inside of the horn, even though it's not going to have absolutely perfect geometry like that. I'm confident that it will be close enough to not really be a problem. Even so, after watching Finless' videos on how to set up an eCCPM bird, I'm sure I'll be able to dial out any unwanted swash interaction with the DX7.

Looks like I'll have plenty of time on my hands here for at least a few weeks... I'll do a full "how-to" writeup soon- photos and the whole shot. I really and truly think that proper ball links for the swash will be the last thing that the FA will need to be a really solid helicopter... I'll let you guys know how she flies once I'm done!

Good thing I keep my resume up to date....

Later!

-Ray

[carloserizzo]

Hey Guys. Ray, I'm really sorry to heard about your lost of job, but think positively: you are very talented, know A LOT of stuffs, and I'm sure you'll give that impression and someone is going to hire you soon.

I’ve been a little disconnected from the forum these days because I started a new semester at college, and that means starting studying, getting out to buy some books and materials… you know how things are.

About my axe, I installed the gyro, ESC, lipo and have flown the heli about 3 times (that must give you an idea about how busy I am). The difference is HUGE. I feel like I don’t need to control the yaw movement anymore. In few days should be arriving the direct tail upgrade, so that’s the next step.

Other thing that has been great news for me: in my college, USB (Universidad Simon Bolivar) there is a mecatronic group, dedicated to develop robotic applications and that kind of stuff. I joined that group this summer, working on camera calibration for robotic applications. I talked so much about helis during summer that they have decided to begin a new project: an autonomous helicopter. Guess who is in charge? Yeap! They gave me the work to choose an heli and design a test platform, for not crashing the heli so many times during test. They bough a century swift 16 heli last summer, but didn’t do anything. They need another helicopter, a smaller one for the test platform. I’m thinking about an helimax mx 400 or an trex 450. What do you think about that?

[Ray K.]

Carlos-

That is GREAT! What an amazing opportunity!

I would recommend a TRex 450 for your test platform. It's powerful, it's design is very simple, and it's going to be one of the cheaper options to modify and repair. My experience with my 'Rex would lead me to believe that it would make a very stable photography platform when properly set up.

-Ray

[tucuso]

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!

[markind]

Sorry about the job Ray! My wife and I knock on wood everyday and say 'thanks god' that I have steady work. I've changed jobs dozens of times but I've been with 3dfx / NVIDIA for about 8 years now, my longest stint anywhere. The gods are smiling on us for now, and its only with their good graces we can enjoy our hobbies.

Hobbies are the lowest priority, if you think about it. How can you enjoy your hobby if something needs fixing at home, whatever it is? You gotta fix the sink/floor/roof/TV/car/job/family first or you really can't relax and enjoy a PASTTIME which by definition something frivolous which passes the time.

This is why in my workplace RC club there is so little activity. Most of the members have more important stuff to do than RC!! Its a sad thing! It makes me appreciate the fact that I have enough freedom to do the RC hobby at all, and nobody can yell at me for not fixing something imporotant because, well, everything is pretty well fixed for us at the moment. Cars are running, kid doing good in school, no money problems, etc etc... Thanks gods!


With that said, before I crash the SOFA2, here are some pics now that I have tidied up the wiring. njoy!

[markind]

What? only 5 pics per post? hmmm... well I had more than 5, so here are the rest///

[markind]

pics...

[Ray K.]

markind-

Looks great! I was thinking about putting my gyro where you have yours, but couldn't really find a good home for the ESC. Oh well. More than one way to skin a cat, right? I'm still working on that ball-link conversion, and have to admit that the geometry is going to be a little more off than I thought. Time for more thinking. I think that I'm just going to go ahead and try it anyway, and use the EPA on the radio to try to dial out any weirdness. We'll just have to wait and see.

As far as the job thing, I'm on alert but not terrified. Fortunately, I was wise enough to sock away some money, and I have about 4 months before the coffers are empty. After even just casual searching, I've found at least 10 good opportunities for me in this area. The best part is that all of them are going to pay me what I'm worth- I found out the hard way that my old employer was ripping me off by about $15k a year. I'm worth about $65k a year according to Monster.com, and all of the prospects I've located are willing to pay me that. So really, I'm regarding this brief hiatus as a chance to re-center myself, and go back to work in a position that I deserve. I have an interview next week with Toyota, and they're even willing to send me to school on their dime. AWESOME! I'm exchanging a dead-end, underpaying job for a much better opportunity. Movin' on up!

It really is too bad that employers don't encourage their employees to have hobbies. Especially in my line of work- I can't think of a better hobby than RC helicopters to help cultivate the type of thought that's useful to engineering firms. Pity.

Until next time....

-Ray

[markind]

FYI - Off topic here:

No doubt! But Ray you are correct - more often than not, a move Out usually ends up to be a move Up.

Yep its wise to sock cash away for those weeks or months between jobs. This has saved my butt more than once in the last 20 years. And yes, its a time for re-evaluation. Think about what YOU want to do for that salary, and add up all your skills and stuff and re-focus into new directions. Its exhilirating, especially when you get that call 'your hired'! WOOT!! :D

These days, if I got laid off for some weird reason, I'd just laugh. Once you get up to a certain level of savings, you start investing. Once you get up to a certain level of investing, you start getting these nice montly dividend checks...

Then one day you add it up and see that the div checks outweigh your takehome pay!! THEN you really start to relax! Time for hobbies!!! :D