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Old Apr 30, 2012, 08:26 AM
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Jurgen Heilig's Avatar
53859 Niederkassel, Germany
Joined Sep 2000
18,763 Posts
Quote:
Originally Posted by Colonel Blink View Post
Oh dear - Programmable mixing and wing mixing are both showing as 'inhibited'....

I'll try:
a) Braiding (plaiting) the wires to the rudder & elevator servos (as a father of a 10yr old girl, plaiting is second nature as I do her hair most nights)
b) If no luck, I'll try a toroid on the pan servo wire
c) Failing all else, I'll put some mixing in to counteract the unwanted movement
...
I would stay away from those actions. If you get an uncommanded control input on the rudder channel, when moving the ailerons stick, there is something severly wrong with your RC system. Take it as a warning sign and have your gear checked. Better safe than sorry.

Jürgen
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Old Apr 30, 2012, 05:08 PM
Wingbreaker
Italy, Lazio, Albano Laziale
Joined Oct 2008
160 Posts
Hello,
I maidened my EZstar I today.
ice flying but ...
... it tend to turn right. Slightly when gliding power off, quite strong under power. I trimmed the rudder for straight and it's 20 degrees left.

I don't see any evidence of not alligned things, wimgs appear stright same for the tail.

I suppose that at least I have to angle the rusheless outrunner motor.
If the plane goes right where should I angle the motor? In a tractor config I would have angled the motor left, but with a pusher with the power applied behind COG?

Thanks for your support

Al
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Old Apr 30, 2012, 06:44 PM
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Zaurak3's Avatar
Nebraska USA
Joined Mar 2008
1,450 Posts
Quote:
Originally Posted by asimmetrico View Post
Hello,
I maidened my EZstar I today.
ice flying but ...
... it tend to turn right. Slightly when gliding power off, quite strong under power. I trimmed the rudder for straight and it's 20 degrees left.

I don't see any evidence of not alligned things, wimgs appear stright same for the tail.

I suppose that at least I have to angle the rusheless outrunner motor.
If the plane goes right where should I angle the motor? In a tractor config I would have angled the motor left, but with a pusher with the power applied behind COG?

Thanks for your support

Al
Al - It should not be turning to the right, especially when power is off. There must be some misalignment somewhere. Also, check the lateral balance for one side heavier than the other.

If it were just turning under power, then you would want to angle the motor with the front end of the motor more right than the rear (prop blast blowing towards the aft port/left quarter).

Perhaps you could post a photo showing alignment for more help.
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Old May 01, 2012, 01:53 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Ilkley, West Yorkshire, UK
Joined Nov 2008
3,631 Posts
Assimetrico:

Congrats on your maiden!!!

I found that my EasyStar flew straight as die on the std Permax 400 & NiMH batteries, the Permax 400 & 2S Lipo and also with a 2700kV inrunner & 2S Lipo. But as soon as I changed to a 3S Lipo (still with the 2700kV inrunner because I'm too lazy to change it for the 2200kV motor I have) I got a pretty severe right turn induced, which really caught me by surprise the first time.

My belief is that the reason for the right bank is caused by the clockwise spinning (seen from the rear) cylinder of air coming off the prop. By the effect of angles of attack etc, this increases the lift created by the left tailplane, reduces it on the right, and creates a rightward 'lift' force on the fin. In other words, it tries to twist the empennage clockwise. This was not evident at the 70W on 2S, but has suddenly manifested itself on the 200W (nearly 3x the input power) of 3S. This is at it's worst on launch when power is high and speed is low (so little control authority to counteract it). On full size a/c like the Piper PA28, full throttle (esp on take off) requires a bootful of right rudder to keep it in a straight line for exactly the same reason.

Now personally I use a 'climb & glide' flight profile and so trimming the turn out using the control surfaces would affect the glide part of the profile, so I didn't want to do that. I have found that what works for me is to launch at far less than full throttle. Especially on 3S, the EZ will fly on half throttle quite happily. At the lower power, the unwanted turning effect is reduced. Once a decent flying speed has been reached and the wings and control surfaces have gained some authority in the faster air running over them, I ramp the throttle up and counteract any tendency to turn with left rudder. All this takes place in probably a couple of seconds.

I avoid launching and banging the throttle straight up to the max - there lies disaster as you are low, slow, have a powerful force trying to force a turn and only low forces available from the rudder & dihedral to counteract it..........
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Last edited by Colonel Blink; May 01, 2012 at 03:27 PM. Reason: speling
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Old May 01, 2012, 06:41 AM
Gravity? No, the Earth sucks
scottdearinger's Avatar
United States, IA, Des Moines
Joined Apr 2011
1,214 Posts
Quote:
Originally Posted by scottdearinger View Post
I flew that other plane of mine into the clouds today- first time I have ever done that- and had a gopro mounted on it for the first time ! Eckace made it into the clouds also- ceiling was at about 1500ft- was too cool- we carried 6 cameras aloft on 2 flights- I got 12 clips to edit together!!!
I best get busy....

Edit done- I only used 6 camera views as movie getting long- but its good!!!

here is link to the "other plane video" I just wanted my EZ friends to see us

http://www.rcgroups.com/forums/showt...9#post21486050
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Old May 01, 2012, 02:53 PM
Wallop!
Martin7182's Avatar
Bussum, Netherlands
Joined Oct 2009
774 Posts
Maidening two new brushless motors

Hi guys,

Maidened two new motors last weekend, a 77g 3900kv inrunner and a 32g 1600 outrunner. So these are about the EZ* extremes in terms of kv rating (without raising the motor position).

Name: 77g_3900kv.jpg
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Description:
77g 3900kv Hyperion inrunner
I knew that the inrunner would become hot but I wanted to test it anyway. The motor has the same shaft as the brushed 400 permax, so I decided to glue the original prop on. I'm not sure but it seems to be 5x4 or so. I reinforced the plastic mount with a thin piece of PCB that I drilled and filed in shape. Total weight as shown in the picture is 96.0g, so including the mount, prop and bullet connectors. The static test results are as follows, at full throttle:

original EZ* 5x4? prop:
2s lipo: 25A, 180W
3s will fry ESC and motor so I didn't try that.



Name: 32g_1600kv.jpg
Views: 44
Size: 186.0 KB
Description:
32g 1600kv RCTimer outrunner
The outrunner is just 32g and it's so small that it fits inside my favourite motor mount; a 35mm film canister. So it's an outrunner that can be mounted like an inrunner . Due to it's near nacelle position I could only mount a 5 inch prop. 6 inch gave 2mm or so clearance, so I didn't dare to try that. Total weight as shown in the picture is 54.3g. The only thing I didn't like was the fact that there are only two mounting holes. This makes it a bit wobbly and during my first static tests the motor became resonant at a certain rpm with the slightest propeller imbalance.

Here are my static measurements @full throttle:

5x5 electric prop:
2s lipo: 4.7A, 38W
3s lipo: 8.8A, 107W


The maiden of the inrunner was a no-brainer. At full beans this thing goes off and becomes small in seconds.
Testing the outrunner was a bit more complicated. I didn't knew if it would stay aloft at only 38W power. With the brushed motor (64W with stock 6 cell nimh) it needed at least about 75% throttle. So I tried the 3s lipo first and tested it flying half throttle, which at static conditions seems to use about 35W. It went well and the 3s being a lot heavier than the 2s this gave me enough confidence to try the 2s lipo as well. To my surprise, it flew reasonably well. It now floats even better than before and stays in the air at about half throttle, which under static conditions is about 1.5A, 11W. I didn't measure the AUW but it should be under 600g now. This is still with heavy wires, heavy connectors (30g), a heavy 30A ESC (30g) and a 2200mAh 2s lipo (115g). So a lot lighter could be possible if I really want to. For flexibility reasons I'll leave the wires and bullet connectors for now. Next step will be to try a 10A ESC (20g off) and a lighter lipo (have to calculate the minimum weight for proper CG first).

Who of you has ever tried small and light motors in the EZ*? How did it fly?
Are there efficient motors available lighter than 32g but still with a 3.17mm shaft?

Let's start the hunt for thermal-May .

Cheers,
Martin
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Old May 01, 2012, 03:36 PM
So I'M meant to be in control?
Colonel Blink's Avatar
Ilkley, West Yorkshire, UK
Joined Nov 2008
3,631 Posts
Quote:
Originally Posted by Jurgen Heilig View Post
If you get an uncommanded control input on the rudder channel, when moving the ailerons stick, there is something severely wrong with your RC system. Take it as a warning sign and have your gear checked. Better safe than sorry.

Jürgen
Jürgen: Yet again you are correct, in that it was the radio system.....thanks!

Having braided the servo wires (on the grounds that it can't hurt...); I spun it up (without the FPV gear) just to make sure I had everything connected up correctly. I noticed that on low throttle (L stick), operating the rudder or elevator (R stick) caused a noticeable variation in motor speed - and not a transient change whilst the servo was operating. So the issue wasn't limited to the pan servo (Ch4).

Swapping the Corona RP6D1 synthesised Rx for the much larger & heavier Hitec Rx which has given sterling service cured the problem..........

Anyone else noticed any 'signal bleed' between channels on the Corona Rxs????
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Last edited by Colonel Blink; May 01, 2012 at 04:17 PM.
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Old May 01, 2012, 04:29 PM
Why so serious?
2500GENE's Avatar
United States, FL, Cape Coral
Joined Dec 2007
5,972 Posts
Quote:
Originally Posted by Colonel Blink View Post
Jürgen: Yet again you are correct, in that it was the radio system.....thanks!

Having braided the servo wires (on the grounds that it can't hurt...); I spun it up (without the FPV gear) just to make sure I had everything connected up correctly. I noticed that on low throttle (L stick), operating the rudder or elevator (R stick) caused a noticeable variation in motor speed - and not a transient change whilst the servo was operating. So the issue wasn't limited to the pan servo (Ch4).

Swapping the Corona RP6D1 synthesised Rx for the much larger & heavier Hitec Rx which has given sterling service cured the problem..........

Anyone else noticed any 'signal bleed' between channels on the Corona Rxs????
What servos are you using? I use the synth Coronas and notice that condition with the cheaper servos like the HXT900 or SG90s but not the HS55 for example.
With your FPV set up functioning you may find the servos doing a dance at times if they can't handle the extra rf interference.

I would have said something sooner but I was in the pool.
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Old May 01, 2012, 04:38 PM
Why so serious?
2500GENE's Avatar
United States, FL, Cape Coral
Joined Dec 2007
5,972 Posts
Quote:
Originally Posted by Martin. View Post
Hi guys,

Maidened two new motors last weekend, a 77g 3900kv inrunner and a 32g 1600 outrunner. So these are about the EZ* extremes in terms of kv rating (without raising the motor position).


So it's an outrunner that can be mounted like an inrunner . Due to it's near nacelle position I could only mount a 5 inch prop. 6 inch gave 2mm or so clearance, so I didn't dare to try that. Total weight as shown in the picture is 54.3g. The only thing I didn't like was the fact that there are only two mounting holes. This makes it a bit wobbly and during my first static tests the motor became resonant at a certain rpm with the slightest propeller imbalance.


Who of you has ever tried small and light motors in the EZ*? How did it fly?
Are there efficient motors available lighter than 32g but still with a 3.17mm shaft?

Let's start the hunt for thermal-May .

Cheers,
Martin
I ran a 1650kv turnigty outrunner on my ez for a bit with a similar mount I made. I reversed the shaft and mounted it on the lip of the mount with the supplied x mount. Used a 7 inch prop that way but wound up likiing the 6x5.5. Worked well on 3 cells though I don't have any data now to post.
I'm still in the pool.
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Old May 01, 2012, 06:13 PM
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Zaurak3's Avatar
Nebraska USA
Joined Mar 2008
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Originally Posted by 2500GENE View Post
I'm still in the pool.
Of course, that would be the `Gene'-pool...
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Old May 01, 2012, 06:51 PM
Why so serious?
2500GENE's Avatar
United States, FL, Cape Coral
Joined Dec 2007
5,972 Posts
Quote:
Originally Posted by Zaurak3 View Post
Of course, that would be the `Gene'-pool...
Women like the gene pool. I invited all the new neighbors over for a pool party. Perhaps I expected too much......
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Old May 01, 2012, 07:02 PM
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Zaurak3's Avatar
Nebraska USA
Joined Mar 2008
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Originally Posted by 2500GENE View Post
Women like the gene pool. I invited all the new neighbors over for a pool party. Perhaps I expected too much......
Looks like you may have a severe case of `displacement' issues there...


(We're gonna need a bigger pool...)
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Old May 01, 2012, 07:06 PM
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H2SO4's Avatar
Australia, New South Wales, Sydney
Joined Jan 2011
2,695 Posts
Quote:
Originally Posted by Colonel Blink View Post
Having braided the servo wires (on the grounds that it can't hurt...)...
I am in no way an authority, but I wonder whether braiding the three conductors does in fact hurt, a little?

In electronics, things get braided and wound to introduce either a particular inductance, or as much inductance as possible (resistance to high-frequency waveforms). Since the servo signal is a pulse train with ~1ms pulses, it's presumably important that the pulse edges (up/down) should be as fast and sharp as possible. True, the pulse frequencies themselves may be measured in milliseconds (an eternity by digital electronics standards), but the sharpness of the pulse edge is determined by much faster waveform transients. In other words, to ensure the pulse reaching the servo is nice and square-ish, the wire may need to be capable of accurately conveying microsecond-length transients, not just milliseconds, and added inductance would certainly impede that to an extent.

Whether it's enough to significantly degrade the signal and perhaps even confuse a servo, that I've got no idea. Presumably an analog servo doesn't really care about edge sharpness since it's not doing edge detection, but I wonder whether more sophisticated digital servos are in fact doing exactly that?

A braided, conductive sheath over the wire would presumably help to prevent unwanted RFI reaching the servo, but twisting the conductors themselves would "round" the pulse edges and induce a corresponding (and tiny) waveform in the positive and negative rails.

Just thinking out loud. I don't know whether the inductance caused by braiding/winding servo leads would be a bad thing overall. Comments?
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Old May 01, 2012, 07:23 PM
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Zaurak3's Avatar
Nebraska USA
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Just more `out loud' thinking, but in an earlier time, servo wires were commonly `braided' with the idea being that external interfering signals induced on the wires would be effectively `cancelled-out'. This is done in other applications as well.

Not as much a problem these days with SS RF causing interference as it appears more of a white noise than the the AM/FM-modulated RF back then, but not sure if there would be much pulse degradation internally due to the braiding - a simple oscilloscope measurement should verify one way or the other.
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Old May 01, 2012, 08:27 PM
OFF TOPIC POSTER
Des Moines IA
Joined Dec 2005
4,811 Posts
I think braided or twisted servo wires was back in the day of brushed motors but i could be wrong.
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