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Jul 01, 2006, 07:37 PM
Got more toys than my kid
macr0t0r's Avatar
Thread OP
Discussion

HoneyBee CP2/Blade CP Brushless Tail motor re-visited


EDIT x2: Just an FYI, but if you are just now reading this thread to do a brushless-tail mod...DON'T. It's not worth the money now that there are real-tail 300-sized Helis out there. If you want a Blade with a real tail, either get a Blade CP, or better yet, get a Compy!
https://www.rcgroups.com/forums/showthread.php?t=611407

EDIT: The final analysis and setup for the brushless tail is found at this post: https://www.rcgroups.com/forums/show...9&postcount=78

Alright, I know the standard consensus is that the dual-tail mod is the best, but I'm still holding this belief that a brushless mod done properly could still be better. I wish to avoid the dual-motor mod due to the added weight at the end of the tail-boom, and I'd really like to avoid the maintenance issue.

Currently, it seems the Feigao motor is the accepted solution, but it seems strange that you need to use a LARGER brushless motor than the brushed one. It also seems counter-intuitive that the brushless draws MORE current.
https://www.rcgroups.com/forums/showthread.php?t=487151

So, with my modified HoneyBee CP2 sitting in front of me, I wish to somehow get a brushless tail on it that actually IMPROVES performance.

My thoughts:

Whatever solution I come up with, it needs to be high-torque so that speed can be varied quickly for best response. Currently, the Feigao motor is lighter than the current outrunners on the market, but the high 4500 kV makes it eat a lot of amps even when using a little 3x2 prop. Even at 17g, it is still a bit heavier than the current brushed tail-system. Being that it's heavier AND draws more current, it seems to be a pretty sub-standard solution.

First off, there is a new 16.5mm micro Outrunner that is being developed by CustomCDR: https://www.rcgroups.com/forums/showthread.php?t=517005
In theory, you could wind this motor to handle the stock tail prop (a deep pitch reduces the need for large changes of RPM for control authority). It's small diameter means there should be little rotational inertia to fight. It could be a viable solution. However, Outrunners can be a tad...unreliable...when starting from a stopped position, so that may cause problems if you do a maneuver using enough Yaw input to stop the outrunner.

Now, there are already micro-brushless motors to be found, but the price is a tad prohibitive: http://www.bsdmicrorc.com/products.cfm?catID=10037
I AM curious if anyone has tried one, though. In theory, these should be lighter AND put out more power. However, it looks like you may have to use the gear-drive, judging by the kV rating.

In any case, I'm tempted to grab the little motor from CustomCDR and use a CC10 ESC on it. Winding the regular 22.5mm motors have been difficult enough, though, so trying to wrap a 16.5mm with my clumsy fingers sounds daunting.

Anyone else still experimenting with brushless tails? What about using the Feigao motor with the stock gear-drive to increase torque and permit use of the stock tail rotor? Granted, it means more weight, but perhaps the current usage would be greatly reduced? Are there good brushless inrunners that are smaller than the Feigao? (Can't find them at the moment).

- Jim
Last edited by macr0t0r; Jan 23, 2007 at 05:08 PM.
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Jul 01, 2006, 08:53 PM
Formerly of mcba fame
Matthew Allen's Avatar
Interesting thoughts, I'd like to see what you come up with. It sounds like the CustomCDR option has the most potential. I had a thought:

What if you set up the proportional for the outrunner in such a way that it never came to a complete halt, even with full left rudder? This would overcome the problem of stopping and starting. I realize that outrunners aren't particularly good at running slowly either, but you would only need to get it going slowly enough that you still had good left rudder response. You might be able to help it along by using a tail rotor with more inertia, i.e. heavier blades, though this wouldn't help with fast changes in RPM.

It would always be a compromise. You obviously want higher pitch for tail response, but for my idea you would really want fairly low pitch. It might be, however, that you could establish some kind of happy mean.

I'll keep thinking...

Matthew

EDIT: On a slightly related note, I would love to see somebody build a NOTAR system for a micro heli, or even any model heli. Now THAT would be cool.
Jul 01, 2006, 09:23 PM
Real men breath methane
WarLordLAN's Avatar
That would be cool and it would get the weight closer to the cg. I doubt that micros have enough down draft.
Jul 01, 2006, 09:25 PM
Got more toys than my kid
macr0t0r's Avatar
Thread OP
A neat idea, but even the full-scale NOTAR helicopters were criticized for the lack of yaw-response. No way a NOTAR would satisfy the twitch-happy thumbs of an RC pilot!

I see your point about using a lower-pitch to allow the motor to spin faster (and possibly to continue spinning). Keeping a wide diameter is still important, though. Will have to think some more on this.

QUESTION: What is the kV of the stock tail-motor? Anyone know?

- Jim
Jul 01, 2006, 09:26 PM
Flying Dirty
Rotorslicer's Avatar
I had 2 honeybee's that's what i learned on then move up to a trex, never look back the trex is so stable compared to honeybee, plus you can fly it in 5-10mph winds, do yourself a fav, move up, you be glad that you did... trust me..it just gets better with a t-rex, why rack your brain with all these issue's ...just move into the higher in, so to speak, you gonna spend more trying to upgrade these thing's plus as i remember the blade tracking was just a plus the all the 370 motors and tail motors that i had to replace it just is not worth it.... with this said...peace Keep'em flying ...glenn
Last edited by Rotorslicer; Jul 01, 2006 at 09:39 PM.
Jul 01, 2006, 10:07 PM
Registered User
Quote:
Originally Posted by Rotorslicer
I had 2 honeybee's that's what i learned on then move up to a trex, never look back the trex is so stable compared to honeybee, plus you can fly it in 5-10mph winds, do yourself a fav, move up, you be glad that you did... trust me..it just gets better with a t-rex, why rack your brain with all these issue's ...just move into the higher in, so to speak, you gonna spend more trying to upgrade these thing's plus as i remember the blade tracking was just a plus the all the 370 motors and tail motors that i had to replace it just is not worth it.... with this said...peace Keep'em flying ...glenn
Yes T-Rex is nice and stable, but it is a mini. There are places to fly where a micro is more suitable and there are place where a mini is suitable.

BTW, the idea that stock CP2 or Blade CP can't fly in 10-15 mph wind is a myth...it's just not true. A better wording might be that T-Rex flies better in 10-15 mph wind than stock CP2/Blade CP.
Jul 01, 2006, 10:29 PM
Registered User
JustPlaneChris's Avatar
Quote:
Originally Posted by uabass
BTW, the idea that stock CP2 or Blade CP can't fly in 10-15 mph wind is a myth...it's just not true.
For that matter, a Honey Bee FP2 can fly in that much wind. I've got video to prove it.

I haven't tried it myself, but logically it seems that a small brushless with the stock gear and tail rotor would work just peachy and never wear out. Why the fascination with direct drive?

I really find it interesting how so many people jump into a thread like this and say "aw, forget these things and upgrade to a Zing Bling XYZ. It's bigger and better."

Well, sure. I guess it might be. But some of us simply prefer the micro helis. We like the light weight, the care-free fun (cheap fun) and the "tinker factor". I've had a big gas heli, and I doubt I'll ever have another now that I've discovered these cute little buggers.

-Chris
-Honey Bee FP2 with Lipos and modded head
-Honey Bee King with brushless power on order
Jul 01, 2006, 10:54 PM
Got more toys than my kid
macr0t0r's Avatar
Thread OP
Heh, I have an old Whisper helicopter for outdoor flying in the wind. I didn't buy the HoneyBee because it was cheap...I bought it because it was SMALL. Often, night-time is the only time I can fly, so having a performance heli that can rip around my garage is ideal.

That being said, I've seen people pour $250 into an 8" airplane for the sake of achieving performance in a tiny package, and I understand why. If I can make my Honeybee fly like a T-Rex in the confines of my garage, I will be a very happy boy!

Now that we've gotten the pre-requisite micro-bashing out of the way, let's get back on topic!

Checked up on the CustomCDR 16.5mm motors. They should weigh around 10-12g. The Feigao motor weighs 17g. The stock motor weighs 7g, but requires the gear drive.

Hmmmmm....I might have to make the plunge on this... If I use a shallow 5" prop, that should be proper air displacement for good control authority without the current draw.

- Jim
Jul 01, 2006, 11:55 PM
Got more toys than my kid
macr0t0r's Avatar
Thread OP
Another thread of a someone trying to improve the situation.
https://www.rcgroups.com/forums/showthread.php?t=515041
Seems that the Feigao with the stock gear-drive is a solution, though still a bit heavy. At least it has less current draw than the DD setup.

- Jim
Jul 02, 2006, 12:51 AM
Registered User
Hmm. I have a DD tail on mine at the moment and a brushless main.

Has anyone tried a GWS EDF-40 ducted fan on the tail?
Jul 02, 2006, 01:25 AM
Got more toys than my kid
macr0t0r's Avatar
Thread OP
Did see someone post that. Although rather cool-looking, it was heavy, and not very efficient. Generally, a plane that moves slowly through the air needs a wide, shallow prop. So, a 3D plane will use a 9x3.7 while a racer will use a 7x6 prop. A tail-rotor is often going so slow it is standing still! So, a wide diameter with shallo pitch is the most efficient. A ducted fan is a small diameter with a deep pitch: good for jets, but not for helicopter tail rotors.

- Jim
Jul 02, 2006, 09:44 PM
Registered User
I've got a GWS Dragonfly (Tower had a $31 sale - couldn't resist), that I mothed (significantly), mostly in between battery charges, while learning how to fly. I switched to brushless main (ARC-20-27-80) and then brushless tail (http://www.bsdmicrorc.com/productDet...95&catID=10037)

The mothed DF is around 165g AUW with a TP 480 2S (total current draw is around 3A at hover); 175g with a TP 730 (goes about 15 mins, 20 mins with all my crashes!) and around 205g with a TP1320.

The brushless tail is pretty pricey, I'm also planning on using it in some micro fixed wings (the cox micro warbirds), if it survives my heli training period (it's pretty delicate!), but it seems to be working really well. I'm running it with a GWS3030 prop, and a CC TB9 ESC (lightened wires). It draws <1.5A WOT, and it's WAY lower than WOT at hover, with all the above battery configurations.

I'm not sure if this helps, since my bird is mothed, but I think if your bird isn't too heavy it should work (not sure of the current draw though). I've also been waiting for the 16.5mm brushless (I'll probaby try it as a main on the mothed DF as well).

If someone wanted my advice (which probably isn't worth much); I'd recommend waiting for the 16.5mm's
Jul 02, 2006, 10:27 PM
Registered User
Very good post OP. I would love to hear a brushless working solution to the tail and I also been thinking about this issue. The one I can think of is by Tmorita but Im not sure if it will work well with a CP.

We don't jsut tinker with it, we know we love it that's why we just want to make it a even better machine. Not that we don't know we can always get a better bird in term of the performance. It's just about the love of the machine But also I guess it depends on personal experience also.
Last edited by cat5; Jul 02, 2006 at 10:39 PM.
Jul 03, 2006, 12:01 PM
Got more toys than my kid
macr0t0r's Avatar
Thread OP
Anyone try this solution yet? A Feigao 1208430S 12x22mm Brushless Inrunner with a 10-tooth pinion on the stock gear-drive.
http://www.bphobbies.com/view.asp?id...05&pid=U832265
The kV is 5250, so it will NEED the gear-drive, but it's quite a bit smaller than the other Feigaos. Only 10.5g! If needed, you could replace the stock propeller with the 4530 propeller and have a pretty reasonable solution. It claims a max voltage of 7.4V, but brushless motors are more limited to WATTS, not volts. Sooooo...with 2amps max, that makes 14.8VA. Using a 3-cell Lipo, that limits current draw to 1.3 amps. Perfect!

Unfortunately...they are out of stock. I need to find another source.

I'm going to have to pull out my lab gear and see if I can get a kV rating on the stock motor, unless someone already knows it?

@Donglass: Yah the Mighty can certainly fill the bill, though I think the kV is still a bit high for efficient direct-drive purposes. I'm surprised you used the 3030 prop. Did you try the GWS 4027 prop? The control response would've been a bit higher for tail-rotor purposes. For economical purposes, I'm keeping my eye on the lower-cost CustomCDR option.

- Jim
Last edited by macr0t0r; Jul 03, 2006 at 12:43 PM.
Jul 03, 2006, 01:26 PM
Registered User
Quote:
Originally Posted by macr0t0r
Anyone try this solution yet? A Feigao 1208430S 12x22mm Brushless Inrunner with a 10-tooth pinion on the stock gear-drive.
http://www.bphobbies.com/view.asp?id...05&pid=U832265
The kV is 5250, so it will NEED the gear-drive, but it's quite a bit smaller than the other Feigaos. Only 10.5g! ....

I'm using the heavier Feigao #1208428 (5300kV) on mine, which I used as a brushless tail on my FP heli for a few years. Mine has a 10T pinion, and uses the stock tail prop & gear. I had to dremmel a little from the mount to make it fit, but otherwise the installation was painless. I'd be concerned about the current rating of your 5250 motor. Only 2-amps...seems low to me, compared to the 5A max of my 5300. Although I'll admit I've never put a meter on mine, so it MIGHT work....just watch the piros!


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