Axe CP separations and setup journal

[markind]

That sounds like a Swash Mix setting. Make one of the setting negative, then test again (with main motor unplugged!). Keep playing with the Swash Mix settings until:

A) Everything is going in the correct direction
B) Regardless of the sticks postions, there is no Binding around the swashplate


In other news,

I have now got 10 flights under my belt on my TREX450SEV2. Today I was in a respectable wind - maybe 8 - 12 knot gusts coming at me. The 'Rex did me proud - hovering around keeping under control as long as I keep to Tail-In maneuvering at stay within 60 feet or so of myself and the lawn. Great fun! Actually starting to relax a bit now...

[Major Bladebreaker]

Hi Folks!

It's been a while since I've written but it's taken me a while to get my Freestyle Hobby tail mod (a month and a half because it sat in Italian customs for several weeks...). I had to pay import tax to the tune of 50 USD so the kit ended up costing me close to $150 bucks! I'm happy to report after much fiddling that the tail mod makes a world of difference with this heli. Combined with a complete microheli head, it gives a Trex feel to it and is actually quite a pleasure to fly. I call it a T-max because the tail mod is made up of Trex parts (the Mod includes an Align tail slider and tail rotor assembly). I'll post pictures here in the next few days.
I have a question about pinions, though. I've already burned out a brushless motor (an Ammo 4200KV/95 watt/12 Amp max motor) as the thing ran very hot and at one pointand literally went up in smoke in the end (complete with autorotation straight to the ground...). My batteries only put out 17 Amps which limited my choice of motors when I separated the thing. I had a 14T pinion on it. Meanwhile I bought a Castle Creations motor with similar specs, put a 15T pinion on it and figured I'd be OK as maybe the Ammo was just a poor quality motor. So far, the CC hasn't gone up in smoke but it's close! It runs extremely hot. Are my pinions too large or my motor specs just plain old insufficient? Thanks!!

Mark

[d3vnu11]

I just wanted to let every one know I successfully flew my CP with the new radio yesterday thanks for all the input guys you've been a great help :)
Regards,
Kevin

[markind]

Y aaay!! Glad to hear it!! New ACP Pilot takes to air! Feels good, eh? Go real easy with it and build up confidence slowly...

[Ray K.]

That's great news!!!!

Markind got it exactly right- just take it slow, and like Han Solo said, "don't get cocky, kid!" Build on the skills that you already have, and take baby steps. The power to weight ratio- even on an ACP- is far greater than any real-life helicopter could ever dream of having. I'm sure you've noticed by now that RC helicopters are quite a handful.

I'm definitely excited that you got her airborne, though- that's GREAT! If there are any other questions about radio setup or other modification issues that you might have, please don't hesitate to ask. You know where to find us!

Keep it business-side up, man!


Mark-

I'm almost positive that your pinion has too many teeth. Just running some quick math here... you have a 4200 kV motor, and you're running LiPo, which means that your motor is putting out 46620 rpm at full boogie. You're running a 15T pinion against a 180T main gear that gives a 12:1 rear ratio, and that will yield 3885 rpm on the head. That is WWAAAAAAYYYYYYY too much, man! The air resistance against the blades at that kind of speed is more than the drive system was ever designed to handle. All of that air resistance is turning into electrical load on the motor, battery and ESC, and it's little wonder that your ESC got smoked as a result. In order to compensate for the huge loads that your head is putting on the drive line, your ESC was forced to pull more Amps than it was rated for. In fact, there's a good chance that your batteries could have been damaged too.

A good target headspeed for an ACP is in the neighborhood of 2500-3000 rpm. In order to get a headspeed of something just shy of 3000 rpm, an 11T pinion should do the trick. In fact, a 10T will also put you in that range. So instead of dropping the cash on another ESC and motor, just spend the $3 or $4 it's going to take to get a pinion with fewer teeth. Aside from the fact that your ESC will love you for it, you'll also be transmitting better torque to the head, which will give the collective more snap and make the head harder to bog down.

Let me know how you do!


-Ray

[markind]

Hi Ray K I think you posted this before but could you recommend a vendor source for these little pinion gears? Thanks!

[Ray K.]

Unfortunately, I really don't have any known vendors. I lucked out with my motor (Park 370) in that it came with a 10T and a 12T pinion, so I haven't really had to search for pinions. That said, the EFlite pinions that came with my motor mesh perfectly with the ACP main gear, and if the motor you're using has the same output shaft diameter as a Park 370, you could use those pinions. They should be available from any vendor that carries EFlite merch. Other than that, I would just check out all the usual suspects and see what they have to offer... ReadyHeli, HeliHobby, Tower Hobbies, A Main Hobbies, etc. There's a good possibility that your LHS has something for you too, so don't forget about them!

-Ray

[Edwinssiv]

Well this seems to be one of the most active Axe CP threads I find...
So...a question. I am having problems with stripping of the main drive gear and I don't understand why. It happens only on powering down quickly. I have used a piece of paper in between the gears to space it as well as plastic baggie piece. Both times it seem that everything is meshed nicely. I am running the Eflite 400 3700kv with 12 tooth pinion, Flight Power 1345 11.1 3s battery, the Great Planes 35A ESC and HeliDirect plastic blades.
Any ideas on what is happening?

[Edwinssiv]

Ok I found out the problem...as I was typing my question I thought about the engine brake. So I went and checked it...the instructions said that it was default set to off but it was on. So either it came in the on position or some how I turned it on....after turning it off I don't see how I could have accidently turned it on.

[markind]

Oh that's ok Ray K I also have a Park 370 I just need to dig up the pinions. I know they are in a little pillbox somewheres...

Oh and I forgot to ask before, my Park 370 is running too hot, despite my nicely modded heatsinks which provide good contact. I also forgot which pinion is on at the moment, but assuming I have the 10-tooth should I try for 12 or vis-versa? Just experimenting again...

[Ray K.]

Edwin-

I think that you're onto it with the motor brake. It doesn't seem like the most likely cause, but on the other hand, it's probably about the only thing that could be doing it. I have a hard time imagining that the rotor head on an ACP holds enough inertia to strip gears, but I could be totally wrong. Also, it's possible that your gear mesh is a little too loose, and you're not getting adequate contact area between the gears. That would also cause stripped teeth. Soooo..... I guess I would try disabling the brake, and setting the mesh just a tad tighter.

Markind-

My motor seems to run a bit on the warm side too, but not so hot as to cause serious concern. I'm sure that you're already using heat transfer compound (aren't you?!?!), but I guess the other thing you could try is to find another heat sink with more surface area. It could also be that if you're using too aggressive of a pinion, it's causing excessive heat in the motor because of the high loads put on the motor.

I've used both the 12T and 10T pinion on my ACP, and I think that I actually liked the 10T better, despite the lower headspeed. The benefit of the higher headspeed seemed to have little effect on flight performance, and my flight duration was slightly reduced. I'm thinking about swapping back to the 10T before flying season is back in full swing. I just don't know yet.... the 12T did seem to do better in the wind, though. I'd start with the 10T, and if you don't like it, go for the 12T.

-Ray

[C R Mudgeon]

Ray ,
I'm coming into this discussion late. But, I have a question about the pinion. Is there a special pitch for the pinion or will any pinion work. The reason I ask I have a motor ( 3200 kv 450hdx motor (http://www.helidirect.com/product_info.php?cPath=385&products_id=4641)) and I was going to use a 13t trex 450 pinion. It should have a head speed of 2300. I'm pretty sure this will work.

--C R Mudgeon

[markind]

Thanks Ray K! I am pretty sure that while the pitch on the tail motor pinon teeth are non-standard, it appears the teeth on the main rotor gear have a standard pitch, so it sounds like a safe experiment to try the 13t TREX pinon.

I think I have one as well so this may be another experiment I will try.

I am leaning toward tinkering my Axe into a nice stable hovering bad boy again, and I have some CnC aluminum head parts I need to use. Specifically, I have HMXE7456, but it is un-useable without HMXE7455, so more money will get (into) the Axe.

Edit: HA! I just learned that to use those CnC parts, you must also have a special main shaft HMXE8316. Guess I'm getting the shaft...

Looks like I will go for the Bell-Hiller mixing mod kit too. It appears to be compatible with all the other HMX aluminum CnC bits. Now that I have some TREX experience, I will know if its my skill or the mechanicals causing any hovering difficulties. heh

The tail now, is a whole 'nuther story. I have the DD and brushless setup, with CC 9A ESC and Gy240, and last I tried it, she could hover just fine, but try swinging the tail around with some rudder input and she was all over the place - quite hazardous. Stay tuned...

[Edwinssiv]

Well...the engine brake was the problem!
I was hovering trying to dial in the 401 gyro...I was on my third lift off and one of the ball links from the bell-hiller upgrade came out! And guess what the only damage was....yep...shredded another main gear! And of course none of my LHS has any in stock...lol..I bought them all last week. So this will be #4 in 2 weeks.:arggg:
So double check those ball links and make sure to loctite them! I thought I had them all but must have missed one.

[Ray K.]

Markind and C R-

I'm just about positive that a TRex pinion will not work. A quick look at the main gear and a loose pinion I have show beyond doubt that the teeth are cut much differently. There's no way a TRex pinion will properly align with the ACP gear teeth. As far as which one of these is considered "standard" tooth pitch, I have no clue. I'm inclined to think that once you get up into .50 nitros, there are probably only about 2 types of teeth across all models. The only thing I can tell you for sure is that I know the EFlite pinions work on an ACP main gear, and it's only a question of if the motor's output shaft is appropriate for these pinions. That's why I just made it easy on myself and used an EFlite motor.

-Ray

[C R Mudgeon]

Dang!
Your right Ray. I checked the pinion on a honey bee fp main gear which is a clone of a Blade CP main gear and it seemed to work. But when I put it against the Axe, :arggg: NFW. Nuts, I just happend to have that motor and pinions hanging around looks like I have to get a new one. I know you are using a 10 and 12t gear. Where did you get the pinions? Did they come with the motor?

Thanks again,

C R Mudgeon

BTW This is a GREAT thread! Great job Ray! :thumbup:

[Ray K.]

C R -

Thanks for the kudos! Yes, the pinions did come with the motor. It's almost like EFlite or Helimax wanted it that way... that the motor would work perfectly on an Axe. If you end up having to get a new motor, I think I got mine from my LHS for about $45 or so... not too bad.

Ray

[Ray K.]

OOOO OOOOO OOOOO!!!!! DID YOU SEE?!?!?!

I don't know how many of you guys subscribe to RC Heli Magazine, but that's MY TRex in the "Letters" section of the new issue!

YYYAAAAYYYYY!!!!!!!

Sorry... couldn't contain myself!

-Ray

[C R Mudgeon]

Super :thumbup: Any Web Links?

[Edwinssiv]

Or if not a link....post a picture of it! Scan it so we can see!
Congrats...it's fun to have a little claim to fame :noteworthy:happyd
Will you still talk to all us little people now that you are a famous builder?

[Ray K.]

Well, I couldn't find a weblink associated with RCH Magazine (they haven't even updated their page to the new issue yet), so I'm attaching the same photo they printed.

And of course I'll still be around now that I'm a "famous builder"!!!! It's just a TRex, and I'm just a normal guy. The comeraderie in this hobby is one of my favorite parts about it, and you bet your fancy aluminum swashplate I'll be around!

Cheers!

-Ray

[C R Mudgeon]

And of course I'll still be around now that I'm a "famous builder"!!!!


-Ray


Now you can get a gig on The Discovery Channel. American Frankenchopper! :)

Excellent paint on the canopy. The Rex looks real nice. :thumbup:

[Edwinssiv]

Ok...I am at my wits end with this thing...I am hoping it is something I am just over looking.
I have been having problems getting the Futaba 401 to work on either of my Axes.
They are set up completely different...I use the Spectrum DX6i TX
First one I have 6 Series Eflite brushless 6 pole moter 2000kv 35A Electrifly Brushless ESC with 24 tooth 64 pitch pinion and the 12A Electrifly brushed ESC for the tail...
Second one I am running stock motor with 20A Esky brushed ESC and the 12A electrifly brushed ESC for the tail.
I have tried to get the 401 to work with either of these helis and it causes the tail motors to pulse so I can not get it to hold the tail at all....I have tried everything I can think of to get this to work. Anyone have any ideas????
:arggg:

BTW...I have a cheapie Esky HH Gyro that will work fairly well on both helis...

[Ray K.]

Edwin-

Do you have your 401 set for a digital servo? If so, the signal frame rate from the gyro may be the problem- the TM ESC may not understand that type of signal, and requires an analog signal. Try setting the gyro up for an analog servo by using the dip switch labeled "DS" and setting it to "OFF" on the gyro. I don't know a whole lot about the DX6i... does it allow you to use your Gear channel as the gyro channel? I've heard of other folks having problems using 401s on ACPs, and it seems to me like radio setup is frequently a problem too. So, try the switch on the gyro, and double-check your radio setup. Lastly, it could just be a simple matter of the gyro gain being incorrectly set up. I wish I could be more help... I'm using a 240 on my FrankenAxe, so this is a problem that I haven't had to solve for myself.

Let me know how you do!

-Ray

[Edwinssiv]

Thanks for responding Ray...I am running it in normal mode(not digital). The 6i does run the gyro from channels 4&5 it will allow me to adjust the gain from it but it does not eliminate the "pulsing" of the tail motor...I will have to try to video it so I can show you what it does...but then I have the Freestyle tail conversion coming so with the elimination of the tail motor I should be fine...I can Hardly wait!
The Heli I have running with the Esky is working good...so I just need the winds to calm down here and I will be out flying beyond hovering my rec room...