HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Aug 31, 2012, 11:28 AM
IHW Heli Division
IntegrityHndywrk's Avatar
United States, FL, Palm Coast
Joined Mar 2012
6,505 Posts
Quote:
Originally Posted by razorblade View Post
I am currently dealing with some AR7200BX cyclic oscillation issues.

The problem is three fold:
  1. The 4F200 is a small 200 size heli
  2. The AR7200BX is sensitive to input voltage and needs a BEC voltage of 5.0 volts when fitted into a small 200 size heli.
  3. The HobbyWing FunFly 40A BEC is measuring at 5.3 volts (+/- 1 volt).
In my latest flight video I am flying with a different ESC, the HobbyWing FunFly 40A ESC with built-in switched BEC rated (on the label) at 3 amps and 5.0 volts. But I measured the actual running voltage to be 5.3 volts.

On the AR7200BX there is a trim pot #1 used to trim cyclic gain. I have it turned all the way down. I can't go any lower. And cyclic oscillation still appears.

So I am considering getting the Castle Creations BEC. Its $24 dollars from my LHS. The output voltage is programmable from 4.8V to 9 volts in tenths of a volt increments. From what I have read and heard is the output voltage is very accurate. Sounds like this will be "a" solution to my problems.
Interestingly enough i have the Hobbywing Platinum Pro 40A ESC in my v450 and it seems to have weird response at the lower BEC output setting with my savox servos. BUT it's labeled as 5.2v output. Where as my Hobbywing Skywalker 40A and 20A are labeled as 5v. When metering the Platinum pro i was reading 5.3v or so. I have yet to meter the other 2. I still use the skywalker on my 4f200. I have never used the 40a one yet. I only recently got it to test with the v450. I could probably get back to you if you want me to check out the output voltage. I'm fairly sure the flyfun models also use a "5.2v" BEC. My issue on the V450 was resolved by switching to 6V output instead. But all of my servos are capable of receiving 6v, i don't know if your ES08s can but your tail servo should be able to. I'm positive your RX will have no issues with that either.

Nice write up on the servo install too BTW!
IntegrityHndywrk is online now Find More Posts by IntegrityHndywrk
Last edited by IntegrityHndywrk; Aug 31, 2012 at 11:36 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 31, 2012, 11:52 AM
Registered User
razorblade's Avatar
United States, MN, Coon Rapids
Joined Feb 2012
308 Posts
Quote:
Originally Posted by IntegrityHndywrk View Post
Interestingly enough i have the Hobbywing Platinum Pro 40A ESC in my v450 and it seems to have weird response at the lower BEC output setting. BUT it's labeled as 5.2v output. Where as my Hobbywing Skywalker 40A and 20A are labeled as 5v. When metering the Platinum pro i was reading 5.3v or so. I have yet to meter the other 2. I still use the skywalker on my 4f200. I have never used the 40a one yet. I only recently got it to test with the v450. I could probably get back to you if you want me to check out the output voltage. I'm fairly sure the flyfun models also use a "5.2v" BEC. My issue on the V450 was resolved by switching to 6V output instead. But all of my servos are capable of receiving 6v, i don't know if your ES08s can but your tail servo should be able to. I'm positive your RX will have no issues with that either.
All the electronics listed that I have used can handle 6 volts:
  1. Futaba S3154 servo
  2. EMAX ES08MD Servo
  3. Align DS420 Servo
  4. Spektrum AR7200BX Receiver

The problem is the 4F200 is small and the beastx 3 axis gyros over-react when the BEC voltage is over 5 volts and that's with the cyclic gain pot on the rx turned all the way down.

I am pretty sure when I install the AR7200BX on a 450 class heli, then I can run the BX at 6 volts.

Another thing, at one time when I had the Phoenix ICE 50A installed on the 4F200 and set the BEC volts to 5.5volts (the only change I did that day) the oscillation appeared. I attempted to mitigate by turning the cyclic gyro gain pot on the rx down. I had the pot all the way down and the oscillation was still there, less of it, but still there. In order to get it running optimal, I returned the BEC voltage back to 5 volts and increase the cyclic gain pot 1/25 turn.

Weird but it kinda makes sense. I don't think these receivers have a voltage regulator built-in them. Which would mean gyro sensitivity is relative to input voltage. And that would apply to all gyros including tail gyros, I suppose.
razorblade is offline Find More Posts by razorblade
Reply With Quote
Old Aug 31, 2012, 01:50 PM
Fly Straight Fly High
tengarang's Avatar
San Jose, California
Joined Aug 2010
3,468 Posts
Hi Integrityhandywork,

After you successfully helped me setup my rx2702V last time, i was inspired to get another one for my other fixed pitch....

I tried it last night and both my cyclics are fried....the reason is the cyclics are analogue and not digital whereas my tail was digital....

do you think from what you know...and this is a question for everyone...that my rx2702V unit is fried? Also I would like to know what the fram rate i.e pulse width constrants this rx2702V could handle.

on my working setup

i was using these for my cyclics on the 2702V

http://www.hobbyking.com/hobbyking/s...dProduct=11627

which has the following specs

http://www.servodatabase.com/servo/turnigy/tgy-390dmh

with a Pulse Width: 1500-1900 Ás.

this wetup works.

my analogues were HS-82 servos from hitech
tengarang is online now Find More Posts by tengarang
Reply With Quote
Old Aug 31, 2012, 02:40 PM
Registered User
razorblade's Avatar
United States, MN, Coon Rapids
Joined Feb 2012
308 Posts
Quote:
Originally Posted by IntegrityHndywrk View Post
Interestingly enough i have the Hobbywing Platinum Pro 40A ESC in my v450 and it seems to have weird response at the lower BEC output setting with my savox servos. BUT it's labeled as 5.2v output. Where as my Hobbywing Skywalker 40A and 20A are labeled as 5v. When metering the Platinum pro i was reading 5.3v or so. I have yet to meter the other 2. I still use the skywalker on my 4f200. I have never used the 40a one yet. I only recently got it to test with the v450. I could probably get back to you if you want me to check out the output voltage. I'm fairly sure the flyfun models also use a "5.2v" BEC. My issue on the V450 was resolved by switching to 6V output instead. But all of my servos are capable of receiving 6v, i don't know if your ES08s can but your tail servo should be able to. I'm positive your RX will have no issues with that either.
Oh another difference between our HobbyWing ESC's...

The FunFly 40A has a switched BEC. The SkyWalker 40A has a linear BEC. Not that it matters, but it could, ya never know - different chip set - maybe. What BEC voltage (running voltage) do you get on the SkyWalker 20A ESC? I have that same one as well.

Another thought comes to mind. The stock 4F200 20A ESC, which had a linear BEC, didn't give me any cyclic oscillation issues.
razorblade is offline Find More Posts by razorblade
Reply With Quote
Old Sep 01, 2012, 09:17 AM
Team WarpSquad
Japan, Tokyo
Joined Jun 2011
2,713 Posts
Quote:
Originally Posted by tengarang View Post
Hi Integrityhandywork,

After you successfully helped me setup my rx2702V last time, i was inspired to get another one for my other fixed pitch....

I tried it last night and both my cyclics are fried....the reason is the cyclics are analogue and not digital whereas my tail was digital....

do you think from what you know...and this is a question for everyone...that my rx2702V unit is fried? Also I would like to know what the fram rate i.e pulse width constrants this rx2702V could handle.

on my working setup

i was using these for my cyclics on the 2702V

http://www.hobbyking.com/hobbyking/s...dProduct=11627

which has the following specs

http://www.servodatabase.com/servo/turnigy/tgy-390dmh

with a Pulse Width: 1500-1900 Ás.

this wetup works.

my analogues were HS-82 servos from hitech

I doubt your RX is dead.
The RX2702V can deliver 4A+ without getting fried. I know. I had a servo on my V450 go bad (short) and it could drop the voltage enough or heat the BEC enough to turn off the RX but nothing extra died (ESC or RX).
thwaitm is offline Find More Posts by thwaitm
Reply With Quote
Old Sep 01, 2012, 03:25 PM
Fly Straight Fly High
tengarang's Avatar
San Jose, California
Joined Aug 2010
3,468 Posts
Quote:
Originally Posted by thwaitm View Post
I doubt your RX is dead.
The RX2702V can deliver 4A+ without getting fried. I know. I had a servo on my V450 go bad (short) and it could drop the voltage enough or heat the BEC enough to turn off the RX but nothing extra died (ESC or RX).
thank you sir
tengarang is online now Find More Posts by tengarang
Reply With Quote
Old Sep 01, 2012, 10:09 PM
IHW Heli Division
IntegrityHndywrk's Avatar
United States, FL, Palm Coast
Joined Mar 2012
6,505 Posts
Quote:
Originally Posted by razorblade View Post
All the electronics listed that I have used can handle 6 volts:
  1. Futaba S3154 servo
  2. EMAX ES08MD Servo
  3. Align DS420 Servo
  4. Spektrum AR7200BX Receiver

The problem is the 4F200 is small and the beastx 3 axis gyros over-react when the BEC voltage is over 5 volts and that's with the cyclic gain pot on the rx turned all the way down.

I am pretty sure when I install the AR7200BX on a 450 class heli, then I can run the BX at 6 volts.

Another thing, at one time when I had the Phoenix ICE 50A installed on the 4F200 and set the BEC volts to 5.5volts (the only change I did that day) the oscillation appeared. I attempted to mitigate by turning the cyclic gyro gain pot on the rx down. I had the pot all the way down and the oscillation was still there, less of it, but still there. In order to get it running optimal, I returned the BEC voltage back to 5 volts and increase the cyclic gain pot 1/25 turn.

Weird but it kinda makes sense. I don't think these receivers have a voltage regulator built-in them. Which would mean gyro sensitivity is relative to input voltage. And that would apply to all gyros including tail gyros, I suppose.
Might give this a try in your line between the ESC and the RX: http://helidirect.com/align-51v-two-...tor-p-7099.hdx

IntegrityHndywrk is online now Find More Posts by IntegrityHndywrk
Reply With Quote
Old Sep 01, 2012, 10:45 PM
IHW Heli Division
IntegrityHndywrk's Avatar
United States, FL, Palm Coast
Joined Mar 2012
6,505 Posts
Quote:
Originally Posted by tengarang View Post
Hi Integrityhandywork,

After you successfully helped me setup my rx2702V last time, i was inspired to get another one for my other fixed pitch....

I tried it last night and both my cyclics are fried....the reason is the cyclics are analogue and not digital whereas my tail was digital....

do you think from what you know...and this is a question for everyone...that my rx2702V unit is fried? Also I would like to know what the fram rate i.e pulse width constrants this rx2702V could handle.

on my working setup

i was using these for my cyclics on the 2702V

http://www.hobbyking.com/hobbyking/s...dProduct=11627

which has the following specs

http://www.servodatabase.com/servo/turnigy/tgy-390dmh

with a Pulse Width: 1500-1900 Ás.

this wetup works.

my analogues were HS-82 servos from hitech
I agree with thwaitm, your RX is probably fine. For servo specs for the 2702V. It's a bit of a clouded issue. But this is what i know.

Servos that work:
The stock v450 servos, which were made to work with the 2702V, are similarly speced to the Hitec HS-5065MG but are not as well made as them, obviously. Also the Align servos for the 450 and Savox SH0257 cyclic and Savox SH1357 tail servos all work with the 2702V. If those won't fit, perhaps you can find something with similar specs that will. The Emax ES08 MD are also known to work with the 2702V.

The servo spec for the 2702V is 1500Ás neutral pulse width, using a 20ms frame rate or 1520Ás @ 333hz. Depending on how the mfg. might label them. Sometimes you can't even find the pulse width spec anywhere.

Good luck! As you've encountered. not all servos play well with Walkera receivers.
IntegrityHndywrk is online now Find More Posts by IntegrityHndywrk
Reply With Quote
Old Sep 01, 2012, 10:56 PM
IHW Heli Division
IntegrityHndywrk's Avatar
United States, FL, Palm Coast
Joined Mar 2012
6,505 Posts
Quote:
Originally Posted by razorblade View Post
Oh another difference between our HobbyWing ESC's...

The FunFly 40A has a switched BEC. The SkyWalker 40A has a linear BEC. Not that it matters, but it could, ya never know - different chip set - maybe. What BEC voltage (running voltage) do you get on the SkyWalker 20A ESC? I have that same one as well.

Another thought comes to mind. The stock 4F200 20A ESC, which had a linear BEC, didn't give me any cyclic oscillation issues.
It's been said that the linear is more efficient for energy but switched is more efficient for heat. Anyway, i'll get back to you on the output of my 20A. I'll have to run and meter it later.

Oh and FYI the Platinum pro has a switched bec. I actually think you can change it to linear too as an option. I forget. But that was the one i had the issue with my servos at the 5.2v setting.
IntegrityHndywrk is online now Find More Posts by IntegrityHndywrk
Last edited by IntegrityHndywrk; Sep 02, 2012 at 12:00 AM.
Reply With Quote
Old Sep 02, 2012, 09:47 AM
Fly Straight Fly High
tengarang's Avatar
San Jose, California
Joined Aug 2010
3,468 Posts
Quote:
Originally Posted by IntegrityHndywrk View Post
I agree with thwaitm, your RX is probably fine. For servo specs for the 2702V. It's a bit of a clouded issue. But this is what i know.

Servos that work:
The stock v450 servos, which were made to work with the 2702V, are similarly speced to the Hitec HS-5065MG but are not as well made as them, obviously. Also the Align servos for the 450 and Savox SH0257 cyclic and Savox SH1357 tail servos all work with the 2702V. If those won't fit, perhaps you can find something with similar specs that will. The Emax ES08 MD are also known to work with the 2702V.

The servo spec for the 2702V is 1500Ás neutral pulse width, using a 20ms frame rate or 1520Ás @ 333hz. Depending on how the mfg. might label them. Sometimes you can't even find the pulse width spec anywhere.

Good luck! As you've encountered. not all servos play well with Walkera receivers.
t han k s
Again for your time and detail I think I'll go with the turnigy servos I posted since I have them
tengarang is online now Find More Posts by tengarang
Reply With Quote
Old Sep 02, 2012, 01:33 PM
IHW Heli Division
IntegrityHndywrk's Avatar
United States, FL, Palm Coast
Joined Mar 2012
6,505 Posts
Quote:
Originally Posted by tengarang View Post
t han k s
Again for your time and detail I think I'll go with the turnigy servos I posted since I have them
Yeah, sorry. I just assumed from the data that i posted you would have figured out that your turnigy servos should work fine. They are a slower pulse cycle at 3ms (according to servodatabase) so they are expecting to be updated much sooner than the 20ms the 2702v puts out. So they may have some odd behavior. Probably, just simply not performing as precise or as smooth as they are capable of because they are being updated slower. But since it's for a FP i don't think it will be any problem at all. I missed the part where you were already using them but the ones that fried were a different set of analog servos. I thought you were shopping for new ones. So is it now that you have 2 FP helicopters running the same servo sets and rx?
IntegrityHndywrk is online now Find More Posts by IntegrityHndywrk
Reply With Quote
Old Sep 02, 2012, 02:56 PM
Fly Straight Fly High
tengarang's Avatar
San Jose, California
Joined Aug 2010
3,468 Posts
Quote:
Originally Posted by IntegrityHndywrk View Post
Yeah, sorry. I just assumed from the data that i posted you would have figured out that your turnigy servos should work fine. They are a slower pulse cycle at 3ms (according to servodatabase) so they are expecting to be updated much sooner than the 20ms the 2702v puts out. So they may have some odd behavior. Probably, just simply not performing as precise or as smooth as they are capable of because they are being updated slower. But since it's for a FP i don't think it will be any problem at all. I missed the part where you were already using them but the ones that fried were a different set of analog servos. I thought you were shopping for new ones. So is it now that you have 2 FP helicopters running the same servo sets and rx?
Yea this would be my second set up just that my first setup uses an hs84 instead of ino lab 261 for the tail

Appreciate you following up and confirming
tengarang is online now Find More Posts by tengarang
Reply With Quote
Old Sep 03, 2012, 07:34 PM
Moving Parts
ChopperJack's Avatar
United States, MS, Columbus
Joined May 2011
1,315 Posts
It Flys Again

After the crash, replacing cyclic servos, and about eight hours figuring out how to set servo arms at 90 degrees, it flys again! Subtrim PIT. and AILE do not adjust individually. AILE adjustment moves AILE and PIT. servo arms opposite from each other. PIT. adjustment moves servo arms same direction (both up or down together). It took me a long time to figure this out. Eventually I found the magic combination.
ChopperJack is offline Find More Posts by ChopperJack
RCG Plus Member
Old Sep 03, 2012, 07:40 PM
IHW Heli Division
IntegrityHndywrk's Avatar
United States, FL, Palm Coast
Joined Mar 2012
6,505 Posts
Quote:
Originally Posted by ChopperJack View Post
After the crash, replacing cyclic servos, and about eight hours figuring out how to set servo arms at 90 degrees, it flys again! Subtrim PIT. and AILE do not adjust individually. AILE adjustment moves AILE and PIT. servo arms opposite from each other. PIT. adjustment moves servo arms same direction (both up or down together). It took me a long time to figure this out. Eventually I found the magic combination.
The best practice is to not use any sub trim or trim but to make mechanical adjustments. If you don't know how you should read up on it. But if your just learning using trims and sub trims is not going to be a problem until you try 3d or inverted flight. Then your trims and sub trims will react backwards. Just my 2 cents.
IntegrityHndywrk is online now Find More Posts by IntegrityHndywrk
Reply With Quote
Old Sep 03, 2012, 07:49 PM
Moving Parts
ChopperJack's Avatar
United States, MS, Columbus
Joined May 2011
1,315 Posts
Quote:
Originally Posted by IntegrityHndywrk View Post
The best practice is to not use any sub trim or trim but to make mechanical adjustments. If you don't know how you should read up on it. But if your just learning using trims and sub trims is not going to be a problem until you try 3d or inverted flight. Then your trims and sub trims will react backwards. Just my 2 cents.
I agree, 100 per cent mechanical alignment would be best in a perfect world. You know, it would be just perfect if those little servo arms would attach to the servo spline shaft perfectly at 90 degrees! Unfortunately, perfect 90 degree mechanical alignment is IMPOSSIBLE. That is why they gave us subtrim. If subtrim will allow you to achieve perfection, might as well use it. Just my 2c.
ChopperJack is offline Find More Posts by ChopperJack
RCG Plus Member
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Another new Walkera! HM 4F200 heli-parkflyer Micro Helis 84 Jan 08, 2011 02:40 PM
Off Site Walkera 4#3 2.4Ghz RTF - Metal Head Version nighthawk0077 Aircraft - Electric - Helis (FS/W) 0 Nov 22, 2009 08:23 PM
Discussion Unique "mixer less" Bell Hiller Head design of the MSR plus Walkera 4#3 Mixer lesss EQMOD Micro Helis 47 Sep 26, 2009 11:59 PM
Discussion 45 Degree Flybar Conversion on a Walkera 4#3 V1 BELL HILLER head EQMOD Micro Helis 13 Sep 01, 2009 11:15 PM
Build Log Walkera 4#3 HH-65 USCG Dauphin--VIDEO 4 Blade head works page6 stevel48 Micro Helis 146 Dec 03, 2008 10:16 AM