Axe CP separations and setup journal

[markind]

It just dawned on me. Its the GYRO. The main motor turns all the way off at zero throttle, but its tied directly to the rcvr. The Tail ESC has the Gyro between it and the rcvr. Not sure why the Gyro is giving a signal when its not moving though...

I'll tinker on this, stay tuned... May try to hop and slide tonight...

[markind]

For the programming part, I just unplugged my main motor from it's ESC and left the "rudder" channel set up as it was intended. Then, by using full right / full left rudder inputs, I was able to program the ESC.

-Ray

Clever! I didn't stop to think sideways...

Son of Franken Axe hovered last night!! First time with BL main and tail! :clappp

The tail was super washy so I upped the Gy240 Gain from 30 to 60. Much better! She was able to hover smooth as glass. Control seemed ok, but my space was limited in the clubhouse. She was very easy to hover with just a couple clicks of trim here and there. Smooth running!! That roughness of the brushed motors is happily gone!

My headspeed was way to high at first, so I went all the way down on Hover Throttle Trim and all the way up on Hover Pitch Trim and she was still just a bit fast, I think. But nice!

The Ammo 3850 on the tail stayed under 140 deg F. The whole time. Acceptable!! Later, I'll add a bit more heat sink and it should be fine.

Unfortunately, even with the e-Flight heat sink properly installed, the Park 370 got up to 180 deg. F and that's a bit high. The good news is if I tweak the main Normal Mode Pitch and Throttle Curves, I can reduce the heat a bit. We'll see... I also might be able to slide the heat sink all the way up, then cut another heatsink to cover the motor's remaining area.

Excellent progress anyway! This has been a fun project! The Axe runs much smoother and the LiPo pack seemed cooler. After the test it was only 104 deg. F.

Once I get the hover nailed down with the stick at about 65% up I can get a good headspeed measurement with my tach and a good current / watts / temp profile of the power train.

btw as expected the CC9A tail ESC and the 20A main ESC were just barely warm to the touch. They have easy jobs, which is what I wanted. Less heat is more efficiency. Less heat on the ESC should translate to less heat on the LiPo.

Looking forward to re-learning my Forward Flight skills! They have been long untried!

:clappp

[AirJet Aviation]

Ray or anybody Please HELP!!!!!!!. I have an AXE and I am getting a pretty good wobble out of the head. I put in a new main shaft but it is still there. Is it the hub? Looking for some answers, it in not real bad but enoying, do AXE's just wobble a little?

What is common cause for this? THANK"S.


Larry

[Phishnvdub]

Check the feathering spindle. If it's bent the head will wobble. Also try to make sure the blades are balanced.

[AirJet Aviation]

Thank you very much!!! A lot better with a new feathering shaft.

Larry

[Ray K.]

Larry-

I'm glad that you found the source of the wobble, but there's a few other "usual suspects" that you may want to note for future reference-

1) Blade tension seems to be a pretty big deal on ACPs. I've had one blade just slightly tighter than the other, and it makes a pretty big wobble (depending on difference in tension) while the head is spooling up and slowing down. I know that all model helis will exhibit this behavior, but Axes seem particularly sensitive to this.

2) Make sure that your feathering shaft screws are completely tight- they have a tendency to walk out a little, even with loctite on them.

3) The "Jesus Bolt" that holds the shoulder block to the mainshaft needs to be as tight as you can get it without cracking the plastic. I've found this to be the culprit on several occasions.

4) The upper mainshaft bearing. It's a ***** to replace, so be sure that it's not just the fuselage screws immediately fore and aft of the bearing. They do come loose sometimes, but I've also burned out 2 bearings so far. When that bearing goes, it's pretty violent vibration that you'll see, so if it's shaking like crazy check that first.

I just got back from my sister's wedding a couple hours ago (8 hours in the car with the gf.... oh boy!), and came back to an envelope from Tower full of ACP goodies, so I should have her rebuilt by Tuesday at the latest. I have this whole week off work, so I should be able to devote all kinds of time to the helicopters. I'm excited to see how these new GWS brushed tail motors work out! Which reminds me...

I was talking to Adam (roommate and BCPP guy) before I left, and we determined that a BCPP tail motor mount *should* press onto the ACP's tailshaft with little or no difficulty. Seeing as they're cheaper than the ACP's motor mount and have a far more graceful design than the ACP's mount, I'm going to try it out with the new motor. It's going to take some very slight modification to accept the new motor, but it's nothing that 5 minutes of Dremel love can't handle. The reason that I decided to try this is that the ACP's mount has kind of a funny shape. The new GWS tail motor doesn't have a very long output shaft, and in order to get adequate shaft penetration into the DD prop means that there would be interference between the prop and the mount with the ACP mount. The BCPP mount will allow for better shaft engagement, as there's virtually nothing for the prop to interfere with. So that's my plan.

I'll let you know how it turns out! And markind- I expect to hear about how the stock ACP tail setup with the BL motor works out under maneuvering conditions soon!

I have to go to bed now. 4 states in 8 hours has a funny way of draining the life out of you...

-Ray

[AirJet Aviation]

Hey Ray,

I just went thru my AXE. I still have just a wee bit of wobble, can you really get all of it out of there? It is much better now. thank you. Question, on normal mode with stock radio are you suppose to have positve pich from 0% on up? In idle up it looks like 10 deg neg 0 50% 10 pos up. I am trying to set up my swash and pitch links but as you know the book is worthless. I need to have the heli set up properly so I can see how shity I am as a pilot. Bought this AXE on ebay, it is in nice shape but I want to make sure all my mechanical adjustments are right. Just liet me know how you would set it up if you were starting from scratch.

I am looking forwrd to hearing how that tail works out.

Thank's Ray get some sleep.

Larry

[markind]

More progress this morning!

I did two 4-minute hovers after tweakin' up the Normal Pitch Curve and smoothing down the Normal Throttle Curve.

The LiPo barely got warm. I'll guess peak at 110 deg. F. It measured 11.2V after the tests. Great!

The Tail Motor and both ESCs barely got warm. Again, maybe 110 deg. F. peak. Great!

The Main Motor maybe, just maybe peaked at around 178 deg. F. Actually, that's not completely insane. I will probably hack in some more heat sinkage, and all should be well.

SMOOTH!!! I can tell too that when she spins down after landing, the main rotor takes a lot longer to come to a stop. Great! Less friction! Looks more cool! :YeaBaby:

I am still putting up with the Tail Motor not spinning down. Its not so bad if I peg the Left Rudder Trim all the way over - the tail still spins but slowly. I can then remove the canopy and disconnect the LiPo pretty safely.

Tracking was dead on this morning. I am still using just one O-ring on each side of the Feathering shaft. Stuffing in the second O-rings just causes huge Flybar friction.

Larry, on the wobble I am still guessing its blade balance. To be competely smooth, the blades must not only have the same mass but also the same CG.

Ray - control issue question: When I raise the throttle to get some altitude, then drop it suddenly, then apply throttle again to avoid thumping the floor, the tail wags around quite a bit, then stabilizes when the altitude stabilizes.

Should I attempt to fix this with the Revo-Mix settings? :thinking Thanks!

[Ray K.]

Larry-

Before I can really answer your question on how to set up your head, I need to know which radio you're using. Are you still using the stock ACP radio? Either way, if you're getting about 10° of pitch in both directions while in idle-up mode, you're not too far off the mark. The important thing is that your pitch values are totally equal at both ends of the stick throw, so that center stick is at 0°. Let me know which radio you've got, and I'll be happy to go over it in detail with you.

markind-

The tail wag that you see with sharp collective changes is exactly the problem I was having, and ultimately caused my last crash. BE CAREFUL!!! It's almost like the tail rotor can't respond to the gyro's input quickly enough. I played around with the gain on the gyro a bit, but it only helped a little and didn't solve the problem- obviously. I think that the stock tail system may be part of the problem... I think that I figured that to be a 1:6 gear reduction in the tail, and that means that tail motor will have to accelerate or decelerate 6 times faster than the rotor itself in order to get meaningful tail response. I'm not confident that the BL tail motor can meet that demand. That's why I went straight to DD, because at least then you've removed that factor. If I were you, I'd go ahead and go to DD and put the 3x3 scimitar prop on- it seemed to be the best setup I've found so far. I really need to figure out what's causing this problem! Again, my gut says that it has something to do with the switching frequency of the tail ESC. I found one at HeliDirect.com that would be suitable- it has 16 kHz switching frequency (double what I'm running now), and it was very inexpensive. I think it was like $15 or so. Hmmm....

Talk to you guys later!

-Ray

[AirJet Aviation]

Hey Fellow Heli driver's,

I am so pissed!!!! What did I do wrong? I hooked up a LI-Po battery that I got from Common Sence and soldered the dean connectors to the battery. Once I hooked it up, it FRYED my ESC. Any Ideas? PLEASE HELP!!!!!!!!! Time to go smoke a pack of marlboro's.


Pissed off Larry!!!1:DH More Money pissed away!!!!!!!!!!!!!!!!!!!!!!!!!!!:flamedevil

[Ray K.]

Larry-

You didn't happen to reverse the polarity on the battery connection, did you? I don't know about you, but it's always stupid mistakes like that that bite me in the ass. I can't think of any other reason that this would have happened... Time to go with full separations!

Helicopters are expensive.

You'll be alright- I've trashed more stuff because of stupid mistakes and/or carelessness on my Axe than I care to admit, and yet I still come back for more. Just be sure to identify the cause of the failure, and learn from it. Stuff like this is the "teething pain" that all new RC heli pilots go through. Think of it as an initiation.... or something.

By the way- you didn't mention which radio you're using... I can't help you until I know what you're working with!

Good luck, buddy! You'll be okay! I promise!

-Ray

[AirJet Aviation]

Yea!!!:BSSLike a dumb shit! I got the wires backwards. I talked to common sence RC, I have the 8C Li-PO's and asked them to send me the 10C Li-PO's they said 8C is not enough power. I bought the 8C cause they were 2 for one in price, should of known 34.00 for two LI-PO's was to good to be true.

On your, I think version 2 frankinAXE it looks like you have the big dean connectors hooking up your battery. I still have the, WELL HAD!!!!!! the eboard with the small dean connector, Freaking things are a ***** to solder, probably why I f@#$%# it up. Do you have 10C or 15C LI-PO's? it sure seems like the stock battery is a POS, I get like 2 min of hover power out of it.

AS far as swash and pitch set up I have the stock radio for now. In normal mode it seems like I have a lot of + pitch with the throttle down, but in idle up it seems normal. I would like to start over so I know it is right, I can't find any information on setting it up. Well, for now back to the Blade CP for learning Take a look at all the CP parts I got. I can Crash the Blade for awhile to learn to fly, cause right now I totally suck!!!!!!!!! Thank's again for your help.

Larry
Pissed off Newbie
Broken AXE!!!!!! Need stock E boared, do to pilot error:bawl
(2) Blade CP's with a ton of back up part's do to lame pilot!!

[Ray K.]

Larry-

I'm using 15C batteries. What the "C" rating is is a measure of the maximum safe discharge rate. It's pretty simple to figure out exactly what that rate is- just take the "C" value, and multiply that by the capacity of the battery. For example, on my batteries, they're rated at 15C and 1250 mAh. 15 x 1.25 = 18.75A safe continuous draw on the battery. The main motor (Park 370) pulls a maximum of 9A, the tail motor pulls about 3A, and all the servos and whatnot probably pull another 3A. So that means that under worst-case load conditions, I'm putting 15A of load on the battery. 18.75 is more than 15, so I'm in the clear. I'm using 20C / 2200 mAh batteries on the 'Rex. The really hardcore 3D guys like to use 25C packs, no doubt because of the higher demand that they put on their electronics. In short, a higher "C" rating will allow you to put more load on and be more abusive to the electrical system. More "C" = more beans.

And yes, I am using the larger Dean's connectors. The Micro connectors are rated for up to 10A, and I believe that the Ultras can take up to something like 50 Amps. They're easier to solder, and easier to connect and disconnect. I like them alot, and have used them on my 'Rex as well- I don't like having to worry if I'm going to melt a connector mid-flight or not. Any disaster that I can prevent is a welcome addition to my helicopter!

So onto the swash setup...

Since you're using the stock radio, your setup will be a little different from that of a different radio. The manual VERY briefly mentions that your servo arms should be parallel to the servo cases when the collective stick is full down in Normal mode, so start there. Once that is done/verified, switch over to Idle Up (you disconnected the main motor, right?) and center the collective stick. You *should* have 0° of collective, but this is what to do if you don't. If your blade tracking is good and you don't want to risk messing it up, you can raise or lower the swash as necessary by equally adjusting each of the swash links. This will make for reasonably fine adjustment of the collective pitch. Otherwise, you can just adjust the pitch links (or a combination of the two adjustments) to get as close as possible to 0° at center stick. A trick I like to use when I'm doing this is to designate a master blade and grip, and mark them with a paint pen or a Sharpie. Use that one master blade as the benchmark for all of your adjustments. I also like to put a dark stripe on the master blade, and then use clear tape to balance the other blade when you go to balance the blades. This way, if you're tracking is off, you can adjust the "slave" blade relative to the master, and you'll know for sure that you aren't screwing with your pitch settings. I make only one with a stripe so that it's REALLY easy to see what's going on when I'm hovering- if I see a stripe on the blade, I adjust the other blade as necessary.

Now, if you were running a separate radio, I would recommend that you make your servo arms level at 0° pitch. I can't really think of why you wouldn't be able to do that with the stock radio, but I figure that HMX recommends that setup for a reason. Since the stock radio doesn't allow for adjustable pitch or throttle curves, I'm willing to bet that setting up the head so that you have 0° pitch at center stick will give the collective ranges desired in both flight modes. In Normal mode, I would only expect to see 3 or 4 degrees of negative collective at bottom stick and about 10 degrees of positive pitch at full stick, and somewhere around +/- 10° pitch in Idle Up. The big thing here is that you have totally equal negative and positive collective pitch at low and high stick in Idle Up mode. If you decide to change the swash height, be sure that you don't go overboard. It's not hard to imagine that if you went too far in one direction or the other you might bottom out the seesaw/slider against the shoulder block, or you might push it up so high that it comes off of it's keyways. In fact, you may want to set up your servo horns, then center the seesaw/slider on the mast by adjusting the swash links, then adjust your pitch links to get 0° at center stick. In fact, that might be the best way to do it. Just be sure to keep your swash level!

Hope this was helpful!!!

-Ray

[AirJet Aviation]

Ray, Thank's again for your help. Question, When I power up, (well, when I had an E boared) Normal mode, throttle back I have about 8 DEG + pitch. My servo's arms are not parallel with the servo housing, but real close in Idle up. how do you adjust the servo arms? Do you pull them off and then put them back on?

I can tell I am a lifer in this RC Heli game as nothing in a long time has pissed me off so much.

Larry

[Ray K.]

Larry-

Wow, man, that sounds kind of jacked up! +8° at bottom stick in Normal mode? That's A LOT. Something weird is going on here. And you said that Idle Up mode seems to be acting correctly? Hmmm.... I'm going to have to think about this one.

How much pitch are you getting in Normal mode with the stick all the way up? As you move the stick from full down to full up in Normal mode, the pitch should very slowly increase until you get to middle stick, then increase faster as you pass through mid-stick and continue up to full stick.

Did you happen to take pitch measurements on both extremes of the stick throw in Idle Up mode? Or what about center stick in both modes? I know that your numbers are likely to be off, but having that information will be helpful in determining what the issue is.

Also, make sure that there is no mechanical binding or interference anywhere in the head system while you're doing all of this- that may be what's doing it too.

Let me know what you come up with, and we'll go from there.

Hang in there, dude! We'll get it!

-Ray

[markind]

Sorry about your Axe headaches, Larry! Dang if I was in Denver I would have soldered those connectors for you, and while I was doing it I would have pointed out that the C rating of those packs are not high enough to drive the Axe.

Commen Sense packs in general are heavy for the charge they supply. The best are Thunder Power, and of course they are the most expensive. But every ounce is critical for a micro heli like the Axe! Whattya gonna do? :dontknow

I used the big conference room again this morning and after upping my Pitch Curve and lowering my Throttle Curve I did two 5-minute hover tests.

Very smooth on the hover, but washy on the control. I see the need for the Bell-Hiller Mod clearly now.

But first things first. The Main Motor is still flirting with the maximum allowable temps, and got up to about 176 deg. F. measured shortly after landing. Everything else is cool. The LiPo finished after two 5 minute hovers at 11.13V, at about 110 deg. F. Good!

But the tail is too squirrelly when Collective Pitch / Throttle is changing rapidly.

Next step: Prepare for the DD tail mod. :bomb:

[AirJet Aviation]

I wish you were in Denver to help me speed up this learning curve!!!!!!!
I am trying to swap my 8 C'c for 15C's and pay the difference. I am kinda screwed till I find another E boared. Don't have the money for seperates right no so I am going to continue crashing the Blade CP till I run out of parts or NOT CRASH!!

I really want to get the AXE airworthy again cause I really like the size and design.
PLEASE keep your eye's open for another E boared for me.

Larry

[Ray K.]

Larry-

Would you like to buy my old e-board? $20 sound okay?

-Ray

[AirJet Aviation]

YES RAY!!!! That sounds good, hell I should give you a bonus for all your help. That would be great then I can get her up in the air. email me at airjet@ricochet.com For the details. Thank's.
Larry

[Ray K.]

Hi everyone!

So I went to my LHS yesterday and bought out all of their BCPP tail cases- 2 of 'em for $3 each. It was funny, because the guys there all know that I fly an Axe and a TRex. They were wondering why on Earth I was buying BCPP parts, but then I went onto explain what I was up to. They got a good chuckle out of it, but it turns out that the BCPP tail case slides onto the ACP tail shaft PERFECTLY! I just mixed up a small batch of epoxy, and glued that sucker down.

The BCPP tail case is a much simpler design than the Axe's, and will be ridiculously easy to modify. There's a small portion of plastic that will have to be ground out to accept a cylindrical motor can, because the BCPP's tail motor is flat on two sides. Other than that, I plan on cutting off the rear portion of the tail case because I don't need any provision for the reduced tail. Simple!

So the point is that BCPP tail cases will neatly fit on an Axe, if you ever find yourself in a situation where you can't get your hands on the actual Axe part. In fact, I would recommend this part anyway- it's a cleaner design, and they're cheaper. It will effectively make your tail boom about an inch longer, so it may have an effect on your CG. Since the boom will be a touch longer, it should give the tail slightly better authority also- it'll have a longer lever arm to act on the fuselage with. On the downside, it's going to increase the helicopter's polar moment of inertia, but I don't think that it will be enough to be a really big deal.

I'll take some photos once I'm done with the mods.

Later!

-Ray

[carloserizzo]

Hi again guys! I had several problems with my internet supplier so I couldn't be able to connect in a long time. I realized some of the post get lost because of an internal problem of this page. Fourtunately, I saved some information from RAYS TM that helped mi A LOT, about the throttle and pitch curves.

THANKS RAY!

Here it is:

-Ray

" Now, onto the curves...

It's actually a pretty simple concept, and I think that it's unfortunate that there's so much confusion about it. Basically, what you're doing when you're setting up a curve (pitch or throttle- doesn't matter) is that you're telling the radio how much signal to send to the Rx for a given stick position. For example, if I want 80% of full throttle at only half collective stick, I would set the center stick position to give me.. you guessed it... 80% throttle and 0° pitch at middle stick. All of these curves (which usually end up looking more like a "V") are plotted as an X vs Y graph on the radio's screen given that your radio has a graphical setup screen, as most contemporary heli radios do. The DX7 has 5 points evenly spaced along the x-axis that the y-axis value can be manipulated at: low stick, mid/low stick, mid stick, mid/high stick, and top stick. This format applies to both the throttle and pitch, but the curves are set up independently. This is good, because the left stick's vertical movement has to control both the throttle and the collective pitch simultaneously. What's better still is that each flight mode (Normal, Idle Up 1, Idle Up 2, Hold) have their own set of curves. This means that when the radio is being set up, you have a total of 4 pitch curves and 3 throttle curves (Hold mode doesn't use a throttle curve- the throttle is full stop regardless of stick position) to set up.

Now this sounds like a lot, but it's really not bad at all. It's one of those things that makes way more sense when you're doing it. Ideally, what you want is to mechanically set up your helicopter so that when the heli's collective pitch is 0°, the collective stick is exactly centered (50% output at 50% stick). Really, I find this part to be the hardest- it usually takes several repetitions of powering up, checking the pitch with a gage, powering down, adjusting, powering up, and re-checking. Not that it's hard, it's just time-consuming and a little irritating because I want to go fly. Once you've got a clean 0° of collective pitch at center stick, the rest is really pretty easy, especially with an electric heli. Nitro helis take a little more tweaking on the throttle curves, because engine RPM may not be totally proportional to throttle position.

I think that this will help to illustrate: When my FrankenAxe is in Normal mode, this is what happens. At full bottom stick, I have zero throttle and about -3° of collective pitch. As I move the stick up, the throttle comes up at a linear rate, as does the collective pitch- because both are being controlled simultaneously by the same stick. By the time I get to half stick, the throttle is at 80%, and the collective pitch is at 0° This is the place where the magic starts to happen- the ramp rate of the throttle and pitch curves change. By the time that I get to full stick, the throttle has only come up an additional 20%, coming to 100% throttle. Now, while the rate for the throttle has dramatically slowed down, the pitch curve is doing the exact opposite of my throttle curve. From center stick and 0° collective, I have a full +12° of collective pitch at full stick. Setting it up like this makes takeoff and landing easy, because the motor (and rotor head) get up to speed right away, but the collective stays relatively inactive until half-stick. Also, this means that full bottom stick has the motor stopped, which is a pretty good idea when you want to hook up or disconnect the battery.

Now this is where the Idle-Up modes come in. In order to hover inverted, you need negative collective and a good amount of throttle. As a result, the curves for the Idle-Up modes look very different from the Normal mode curves. Since the 50%+ stick portion of the Normal mode curves offer very good upright flight performance, there's no reason to change them. The difference is that when I switch to Idle-Up and I want to fly inverted, -3° of collective is not enough, and throttle dropping sharply toward zero as I pull the stick lower is NOT what I want. So, when I'm in Idle-Up 1 and at full bottom stick, I have 100% throttle and -12° of collective pitch- it's a mirror image of the "top" half of the Normal mode curves. In other words, the XY plot of the throttle curve in Idle-Up 1 looks like a shallow "V"- it starts at 100%, reduces to 80% at middle stick, and ramps back up to 100% at full stick. Conversely, the pitch curve in Idle-Up 1 is a straight line, from corner to corner on the plot. At bottom stick, I have -12° of collective pitch (and 100% throttle), the pitch is at 0° at center stick (and 80% throttle), and at full stick I have +12° pitch and 100% throttle. I should point out now that I have my throttle and collective values absolutely identical to each other above center stick across all 3 flight modes, and it's for an important reason. As long as I'm flying upright, I can switch between all the flight modes and have no change in the helicopter's performance. It wouldn't be very cool to be putting along in Normal mode, decide to hit the Idle-Up switch, and suddenly gain throttle or lose collective or whatever. That would be BAD!

Basically, you set up your pitch curves to give you the collective range that you want, and then you can adjust your throttle curves to give you the power/headspeed that you want for a given pitch angle. My curves are very very simple- I only use 3 or the 5 available adjustment points, and my curves are actually two straight lines- one from 0% to 50% stick, and the other from 50% to 100% stick. I have the ability to use exponential curve rates, but I've not found that necessary. What expo does is that it truly "curves" your curve- it will no longer be linear; rather a smooth and flowing bend between value setpoints. You may be wondering about the 2 points that I don't use- I set the radio to "inhibit" these points. When you do that, the radio just jumps to the next known setpoint and makes a straight line (or expo curve) between those points. It's good to have 5 setpoints (some radios even have 7), but I've found that I don't need them for either of my helicopters.

Wow.. that was a bit more long-winded that I was hoping for, but I hope it was helpful!

-Ray

[carloserizzo]

LITTLE HELP HERE PLEASE!


Guys, I still have my stock axe cp, until my gy 240 and tail ESC arrives. The last fly I made, I was like 4 minutes hovering (yeah yeah, I still have the stock battery). Then, I charged the battery to go for more hovering. When it was done, I went to my yard for the flight, powered up my axe and SURPRISE! I started giving it some throttle and it started spining really fast. I slowed it down and tried again... nothing got better.
Then, I started playing with my gyro (the one in the eboard), seems like it worked but just for a minute, then it started spining again. I continued playing with the gyro (with the gain), but the motor stoped COMPLETELY. Its just dead now. I tried with the transmitter trim, and then again with the gyro, but now it doesn't do ANYTHING!

I would like to know if I fried the gyro because of bad operation (I changed the gain without turning off the heli, and dont know if you can do that), or if it is because the tail motor is just dead.

Thanks a lot.

[Ray K.]

Well, first things first...

Carlos-

That sounds like a dead tail motor to me. A quick and easy way to check it is to take a 9v battery (or something similar) and just apply power directly to the tail motor through it's extension lead. If the motor doesn't spin, it's fried. If you need to replace it, keep reading- I listed the tail motor that I'm using now, and it's a much cheaper way to replace the stock tail motor than buying another HeliMax motor. It cost about $10.

Now onto the FrankenAxe...

I finally got her all put together last night, and took her out for some test flights today. This is absolutely the BEST configuration I've flown with so far!!! I swapped the 10T pinion out for the 12T, and I'm using a DD tail with a GWS brushed tail motor. As much as I hate to admit it, the brushed tail works way better than the BL tail. I'm not giving up on the BL tail motor; I just have some research and testing to do before I try it again. Anyway, if I were to tell somebody how to build the ultimate separated Axe CP, this is the recipe:

E-Flite Park 370, 4100 kv main motor with 12T pinion / Castle Creations ThunderBird 18 ESC
Futaba GY240 gyro / ElecrtiFly C7 ESC / GWS EDP-50XC motor / GWS 3.25x3 scimitar prop
ElectriFly BP1250 Lithium Polymer batteries (11.1v / 15C / 1250 mAh)
Hitec HS-55 servos
MicroHeli CNC swashplate
HMX CNC flybar cage
Programmable radio of choice

The reason that I jumped up to the 12T pinion is because I wanted more headspeed. There is nothing wrong with using the 10T- this change was just personal taste. I should note, however, that the motor sounds much happier with this pinion, and cyclic inputs are a bit crisper with the additional 500 rpm that this pinion gives over the 10T. Under extreme collective jabs the motor bogs a little bit, but I also had my throttle curves relaxed a little because I didn't know what to expect with the new pinion. I'm sure that putting them back to how I had them will fix that.

I tried the new tail motor with the GWS 3x2 square prop on my first test flight, and wasn't really pleased with it's authority. It held the tail just fine, but strong rudder inputs felt weak. So I swapped props to the scimitar prop, and the tail responded much quicker. When I was fooling around with the BL tail motor, it absolutely provided more piro power, so that's why I'm not giving up on it. If I can just solve the response problem, the BL motor will certainly be the better pick. This setup definitely works very nicely though- the tail is solid, and doesn't skip a beat with hard collective punches. Certainly way better than stock!

As I mentioned in a previous post, I borrowed a Blade CP Pro tailcase to do this build. I had to modify it a little bit to accept the motor, but it fit the Axe's small aluminum tailshaft (the little cylinder that's pressed into the tailcase and bolts to the tailboom) perfectly. There's no way that it would be secure without a little glue, but the Blade's instruction book has you glue the tailcase to the tailboom, so no worries. They recommend CA glue, but I used some 5-minute epoxy just to be sure. It came out very nicely, I think, and should hold up very well. I included some photos of the modified part, and my final tail mounting orientation.

In a nutshell, if you're looking to separate your Axe, use the recipe in this post and refer to the first few posts of this thread for the "how to". This is BY FAR the best my Axe has ever flown!

Later....

-Ray

[markind]

Great progress Ray!! How did you fix the prop to the tail motor? CA glue?

Any guess as to why the DD brushed tail motor responds better that a BL DD tail?

Any guess if the 12T pinion is reducing the main motor operating temperature?

[Ray K.]

markind-

The prop isn't really fixed onto the motor shaft with anything other than friction. That's actually part of the reason that I flipped the rotor back over to the right side of the helicopter- the prop will push itself onto the shaft in this orientation. When a left piro is called for, the prop simply stops spinning at worst, so there's really not much need to secure it very hard. With the BL motor and the way that I had it flipped it was possible for the prop to pull itself off of the motor, so I was using just a dab of CA to hold it there. Not so much that it couldn't be removed, though.

It's really hard to say at this point with the lack of information that I have about brushless technology why the brushed motor works better. Several pages ago in this thread, Curtis (mashburncs) pointed out that there is a response lag associated with brushless motors. I think that it's possible that this is the problem I'm having, but I also think that the switching frequency on the ESC (PWM- Pulse Width Modulation rate) might hold the problem too. Again, I don't know much about BL at this time, but it seems that an ESC that can send switching commands to the motor at a higher speed and resolution would be a big help. The DD props that I'm using are super-light, so there can't be much inertia from the prop itself. The motor's response rate or the ESC's control rate, or both, must be the problem. I saw a video on YouTube of a guy with a BLDD tail on an Axe, and he was doing some very aggressive 3D with it, so I know that this can work. I'm almost certain that it's a hardware issue. Like I said, I still have some learning and testing to do, but I'm confident I'll get this figured out. It's just going to take some time, that's all.

As far as the main motor and it's new pinion, I'm certainly paying a small penalty in flight duration. The motor itself certainly isn't running any cooler, but I don't think it's really much hotter either. The battery and ESC temps seem to remain unchanged. I really need to get a thermometer! I'm really happy with this pinion, though- the helicopter "pops" a lot better, and cyclic control is more direct. It's a keeper!

Now I need to do some homework on brushless motors and ESCs....

-Ray