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Old Jan 11, 2007, 09:02 AM
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Joined Oct 2006
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For some early morning laughs, I uploaded a video of my CX2 for you guys!

http://www.rcgroups.com/forums/showt...67#post6711202

Hopefully the new boom will improve my already amazing (tee hee) aeronautics skills!
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Old Jan 11, 2007, 10:03 AM
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Roswell, GA
Joined Jun 2004
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Has anyone experimented with restricting the travel of the flybar to reduce it's max authority?

Just thinking that might be an alternative to making it lighter or shorter - theoretically it would keep the stock stability during mild maneuvering (until the flybar runs out of travel) but allow greater overall maneuverability & reduce the risk of blade clashing.
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Old Jan 11, 2007, 10:28 AM
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Virginia
Joined Jan 2007
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Just an out of the ordinary question here, but I just swapped out my stock motors with the Vortex moters. As I was "breaking them in" (just let it run on the floor at about 30% power), I hear it start to "twitch", then all of a sudden, one of the motors stopped! I cut throttle down and tried it again, but the one motor wouldn't work. I unplugged it and plugged in the stock one and it worked. So I tyried the Vortex one again and it worked fine. I started to break them in again, this time about 20%, and I heard that twitching again. Not a lot, but just real short quick twitches. I then held it and gave it full throttle for about 10 seconds. When I tried to trottle down - I got NOTHING! No radio response whatsoever! I unplugged the battery and plugged it back in and it worked fine for the next few minutes. Not sure what the heck happened there, but does anyone have any suggestions???
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Old Jan 11, 2007, 11:19 AM
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United States, KS, Pittsburg
Joined Mar 2005
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Sno-Flyer.. I'm not sure what's going on there, I wonder if the motors are getting hot from being ran like that. I wouldn't think thy would. Do you have any ventilation to the canopy?

When I raced RC cars, we would break in the motors by putting the motor in a glass of water and then taking a low volt battery and connect it directly to the motor (the smaller the motor, the lower the volt). A nice long run time of about 10-15 mins at a slow to medium pace on the motor is what I always liked to see. After that we would dry the motor out with some compressed air, and then a drop or two of bearing oil (there was a few companies that produced oil just for motor bearings).

Everyone had their own method, but this one worked well for me. The water kept things cool and lubed enough to not arc, but still let the brushes cut to the shape com.. It also carried away the carbon dust from the fresh cut brushes.

In your case Sno, you might be picking up some arcing from carbon dust buildup from cutting the brushes. If the motors were tight, then there is probably more friction at the brushes, causing them to cut a bit harder, and producing more dust. The arcing can cause small interference, but most likely is just making the sounds of it.

Take a look inside the "vents" on the motors and see if there is a bunch of black dust, if there is try blowing some of it out. You can take some compressed air to it, but watch that you don't blow any grease or oil off the bearing/bushings (not sure what these motors use), just blow the air lightly through the vents.

That's my 2 cents.. It might not be right, so please take it with a grain of salt. I'm pretty new to the heli biz, and my brushed electric motor experience is strictly in rc cars, as all my fixed wing models were converted to brushless before any maidens.

----------------------

Brett,

Limiting the travel could probably lower the blade clashes, as it would keep the heli from maneuvering so violently, however, I would think you would loose a bunch of performance in everything except hover. I think the largest problem with the blade clashes are due to the flexibility of the blades. When you start to toss the bird around, the blades start to flex pretty hard as they try to lever the model to the direction that your intending it to go. Limiting the movement of the flybar would cause the heli to not be able to get to maneuvering so wild, and therefor would lower the blade clashes.
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Old Jan 11, 2007, 11:35 AM
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Salt Lake City,UT
Joined Nov 2006
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NS I am going to try your method to break in the Vortex motors. Hopefully it works out well.

I was with the stock setup other than the motors. I wonder if that had any thing to do with our different results. I will try breaking them in this weekend when I have time and I will get back to you on them.

Let us know how it flies at your work.

Ed
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Old Jan 11, 2007, 11:58 AM
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Roswell, GA
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My thinking is the flybar reduces maneuverability by trying to keep the top rotor from changing paths, it's a restoring force rather than helping it follow what the airframe is doing. So reducing how much it'll be able to correct should let the upper rotor follow the helicopter better, at the expense of stability once it hit the limit.

Should be easy enough to test, if the wind ever quit blowing here I'll play with it a bit
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Old Jan 11, 2007, 12:27 PM
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United States, KS, Pittsburg
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Ed,

I should get a chance to fly it in a bit here. The ceiling is only 10 foot, but there's plenty of room to get it going forward and side to side, and should be a lot of fun. I'll try to dig up some more info for ya on the break in. I remember there being some good thread on here somewhere a while back that had much more specific details on the process, but over all it's really easy.

I wouldn't think the stock setup would have anything to do with the motor problems. From my comparisons, the only difference between the two setups is the spaceing on the rotor heads. Everything else was the same.

Noah G.
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Old Jan 11, 2007, 12:28 PM
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United States, KS, Pittsburg
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Brett,

The flybar works a lot like a gyro, the weight at the end of the bar keeps it rotating in the same circular plain, and as a result forces the top blades to NOT change directions. This is what keep the heli so stable. The flybar will fight the heli's attempts to change attitude (nose down/up/forward, side to side etc.) If you limit the movement of the flybar, you will reduce the amount of movement the heli has before it is forced to change the plain of the weighted flybar, which is difficult for such a light heli to do.

I think your on the right path with thinking, however, the flybar is a staying power, reducing it will cause the heli to hit the resistance sooner, and will take more force to start to change paths. With a very open flybar, you can tilt the heli forward a great deal, an achieve good motion without changing the path of the flybar. With a limited travel, the amount you will be given before you have to fight the flybar's plain of movement is much less, resulting in the majority of the force that was intended to go into forward movement being used to change the plain of the top blade.

The bottom blades "move" the heli, the top blade "stabilize" the heli. Ideally, you would like the flybar to have enough movement to allow the heli to "swing" in any direction without changing the angle of the flybar. A flat spinning flybar is like a top, and will move up, down and laterally with ease, but changing the angle of the spin is very difficult.

Noah G.
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Old Jan 11, 2007, 12:58 PM
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Roswell, GA
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I think I'll see the opposite - more flybar travel means it can change the upper rotor cyclic pitch more as well, so more power to try & keep it level (as defined by the flybar's path).

I'm basing this on full-sized helicopter experience, could definitely be wrong but there's only one way to really find out...
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Old Jan 11, 2007, 01:11 PM
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Hi all:

Any thoughts on post I made about shortening the lower blades?

Robert
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Old Jan 11, 2007, 02:00 PM
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United States, KS, Pittsburg
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Hey Robert,

I read the post this morning, but was in a hurry to get to work, and hadn't commented on it yet.

The mod sounds good. I figured you would have to trim it out again with the shorter blades, it's not much but the lower rotating mass will cause it to spin easier.

I'd like to hear how the shorter blades work out when you get wild with it. I'm betting that your going to see some more pep from it as the blades should spin up a bit faster being shorter. And the lack of clashing will be a nice change!!!

Please let us know how it works out for ya when you get a chance to ring it out a bit. I've only got one broken lower blade right now and replacements are limited, but as another broken one comes along (and with my flying.. that shouldn't be long.. ) I think I'm going to trim mine down. You went to 5.5, I might try 5.75 and see what it does. I can always trim off more, but you cant put it back on...

For a mild little trainer, these things a lot of fun. Must be that hot rodder in me getting such a kick out of seeing all the ways one can mod this little bird.
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Old Jan 11, 2007, 02:20 PM
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Aurora, CO
Joined Apr 2003
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Quote:
Originally Posted by Peregrine Falcon
I did leave the screw at the top off. I read about doing that somewhere and it makes sense. Now, when I crash, the flybar just pops off.
EVERYONE should do this. I wish it shipped without the screw in place.

I've had a dozen crashes with mine (gettin' crazy with it...that and letting friends fly it! ) and I haven't bent a shaft or broken anything but blades and skids. In fact, I've only had to bend the flybar back in a few of those crashes.
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Old Jan 11, 2007, 04:02 PM
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I got the chance to fly the CX2 in the training room. Like I said the ceiling isn't very high, so I couldn't go ballistic in there, but I did get to ring it out a bit, and I'm pretty happy with it.

I got a full 10 min flight out of the deal with the stock battery, and while I couldn't go very high, I sure did give it all I could in that little space. I really don't like to, but I let it go to the LVC this time to see what type of time I could get. This weekend I'll fly it in one of the gyms and I'll time it again then to see if it's consistent.

With the mods, I was able to maneuver MUCH better, and it was noticeably more powerful and quicker!! I adjusted both the elevator and aileron links out one notch, and I think that is the biggest contributor to the better agility of the bird. With the vortex gear, I experienced no blade clashes, again. I'm not throwing it around like I will in the gym, but several time I did take it full click across the room, and slam full reverse. The bird doesn't like it much, but no blade clashes at all. The little sucker would almost be pointing straight up for about a quarter second though..

I hope you guys get the motors going. Did everyone get theirs from BP? I hope I don't jinx myself, but I'm pretty darn happy with mine. I will probably order a new body and boom for it next week, and start looking for places to lighten it up.
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Old Jan 11, 2007, 04:56 PM
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Twin Falls, Idaho
Joined Jan 2005
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Peregrine..

"Battery question:

By the way, can any one tell me if you need to make any modifications to fit the common sense battery? I saw on a thread where the manufacturer posted detailed instructions on their web site as to the steps necessary to get a good fit. But that included trimming the canapy, cutting the battery holder and using either tie wraps or velcro. I'm hoping I don't need to do any of that. And, what about the mega packs I keep hearing about, can you just take out the spacers and electric tape them back to fit"?

I have run tests on the stock E-flite packs, the Mega packs and the DN Power packs.
Check out the last couple pages of this thread...

http://www.rcgroups.com/forums/showthread.php?t=582090

The Mega packs only needed the spacers removed. I even used the same tape to reassemble it.

Roger
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Old Jan 11, 2007, 05:19 PM
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Virginia
Joined Jan 2007
10 Posts
Re: Vortex Motors

Hey all--first post, but I've been lurking about a month reading while learning my CX2.

I just installed the Vortex motors from BP--experienced the same issue with flight time for the first two charges I ran. Third was markedly better. I'm about to do the fourth.

I agree with others who have posted that these motors are quieter and run cooler, though performance may be a placebo effect. They definitely are no worse than the stock motors. I think given 5-7 charge runs, the flight times will be close to stock.

This toy is just too fun to tinker with. I'm running all CNC aluminum parts possible so far (marked increase control stability over plastic), Vortex motors, stock blades, and control arms moved to the 2nd bell housing hole.

I didn't think it was possible, but I can now confirm the CX2 is indeed capable of a five to seven second hover without any control changes. Of course, the only adjustments I have not made yet are to the gyro's gain.

Cheers,

Justin.
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