Fun, Learning, Friendship and Mutual Respect START  HERE


Unregistered
Go Back   HeliFreak > R/C Helicopters > Main Forum - Helicopter Talk


Main Forum - Helicopter Talk R/C Helicopters and the people who fly them. VENDOR TOPICS DO NOT GO HERE. Full Scale Heli threads go in OT please


Reply
 
LinkBack Thread Tools Display Modes
Old 01-02-2013, 07:00 AM   #1 (permalink)
Registered Users
 
Posts: 2,832
 

Join Date: May 2011
Default Would mixing Cyclic servos make that big of DIFFERENCE?

I currently have futaba bls351 on cyclic but yesterday one crapped out on me. I have a bls255HV available to me and was wondering if I could try it on cyclic combined with the two remaining bls351, the 255 is faster but at high voltage, Im guessing at regular 6v they should be close with speed. I am running a vbar 5.3 silverline. Can I get away with doing this?
__________________
Trex 700L NEO / Mikado Logo 600SX Vbar 6.0/ Trex 470LM NEO, Oxy 2 CC Talon 25 NEO, 450 pro vbar 6.0pro/ Trex 700n DFC OS105HZR, Velocity50 Vbar 6.0pro -Oxy 5 NEO-/Trex 600efl PRO (Night Flyer) vbar/CC HV80 ......ALL VBAR CONTROL
Stevin is offline        Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 01-02-2013, 07:03 AM   #2 (permalink)
Registered Users
 
Posts: 671
 

Join Date: Nov 2009
Default

im gonna say dont do it
kheinink is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 07:10 AM   #3 (permalink)
Registered Users
 

Join Date: Sep 2011
Default

Best not with fbl.

If it's only temporary and are going to do it anyway put it on elevator.

Sent from my GT-I9300 using Tapatalk 2
__________________
Gaui X5 Formula SK720
Trex 600 EFL Pro AR7200BX
Trex 450 Pro DFC HC3SX
Blade MCPX BL
Stanley Speel is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 08:20 AM   #4 (permalink)
Registered Users
 
Posts: 487
 

Join Date: Feb 2008
Default

I asked that question at a LHS and they said not to mix servos cause the gear ratios could be off a little impeding radio response. I believe them, it makes sense.
__________________
Trex 500ESP - Gaui 425 - Gaui 550 - MCP-x




Robertwav1 is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 10:18 AM   #5 (permalink)
HF Support
 
Posts: 34,290
 
My HF Map location
Join Date: May 2006
Default

Not a good idea. The speeds of the servos are quite different as are the torque values. On a 3-servo setup, the servos work in concert to move the swash. Having one move faster or slower than the other tow will introduce some weird effects on the swash, especially with collective changes.

If you're bent on trying it, do as was suggested above and put the 255 in the elevator position.
__________________
-Kevin

No helicopters were harmed in the creation of this post.
AMA CD # 7309, Turbine Waiver# RW 890
Click Here For Bergen Intrepid Turbine Build Videos
Skiddz is online now        Reply With Quote Quick reply to this message
Old 01-02-2013, 10:58 AM   #6 (permalink)
Registered Users
 

Join Date: Aug 2010
Default

Quote:
Originally Posted by Stevin View Post
I currently have futaba bls351 on cyclic but yesterday one crapped out on me. I have a bls255HV available to me and was wondering if I could try it on cyclic combined with the two remaining bls351, the 255 is faster but at high voltage, Im guessing at regular 6v they should be close with speed. I am running a vbar 5.3 silverline. Can I get away with doing this?
My question is why? I am thinking you are desperate to fly, but...It is winter, even in NY I think. Just order a new servo.

On the other hand, you don't need our permission to do whatever you want. You do probably need to reset up your v-bar to make sure the servo endpoints (I guess is done in the vbar) are ok and not binding.
ahahn is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 11:00 AM   #7 (permalink)
Registered Users
 
Posts: 2,055
 

Join Date: Jun 2012
Default

I would say don't do it, but I'm going to disagree with Stanley Speel and say if you're going to do it at all, make sure it's on a FBL setup (as on a flybar it really would move to wherever you commanded it, and if it has different gear ratio it would put the swashplate uneven and make you crash)

On a FBL heli, the controller will put the servo wherever needed to make the heli do what is commanded by the radio.

And if you do it, put it on the elevator.

(I'm still not saying to do it though)
__________________
XL Power 520 / Spektrum DX6
PcChip is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 11:58 AM   #8 (permalink)
Registered Users
 
Posts: 1,712
 

Join Date: Aug 2007
Default

I wouldn't even try it...
__________________
Lean not on your own understanding.

Protos Max V2, Goblin 630, 500
silas3d is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 01:04 PM   #9 (permalink)
Registered Users
 
My HF Map location
Join Date: Nov 2006
Default

I wouldn't even do it at all...not worth it.
__________________
Team Mikado USA!!!
Team Scorpion!
Logo 600SX - Scorpion 4035-560, 10s 4400 packs
Logo 690SX - Stock Scorpion motor, 12s 4500 packs
sgrim80 is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 01:10 PM   #10 (permalink)
Registered Users
 
Posts: 212
 

Join Date: Oct 2010
Default

I have heard the same things that have been said. The speed will be off causing some interactions in the swash. I would stay away from that idea.
__________________
TT E720 w/ SK540
Trex 600N DFC w/ OS 55, CGY750
Trex 500 DFC w/ SK540
Trex 450 Sport FBL w/ SK540
Futaba 14SG
Vermillionx is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 01:15 PM   #11 (permalink)
Registered Users
 
Posts: 6,970
 
My HF Map location
Join Date: Oct 2008
Default

simple answer - on electronic CCPM systems its a no. If no other options elevator might work but again as some mentioned. Even adjusting end points speed and torque is different so its not worth it to me.
im4711 is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 01:19 PM   #12 (permalink)
Registered Users
 
Posts: 2,829
 

Join Date: May 2006
Location: Woodstock, GA
Default

I think it would be an interesting experiment. As noted above, the FBL controller should compensate and drive each servo as needed. My guess is you'd never be able to tell the difference in flight!
__________________
Team Synergy / Rail Blades / Morgan Fuel
beeflyer2 is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 01:56 PM   #13 (permalink)
Registered Users
 
Posts: 3,008
 
My HF Map location
Join Date: Apr 2008
Default

Do a YouTube search for Rob Cherry. Watch his x5 vids. Those vids are witha vbar and 2 different brands of cyclic servos. This heli has been like this for over a year.
__________________
Screw It, I'm gonna fly.

In search of a 500-600 sized heli.
Preferably rtf with vbar.
povern is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 04:07 PM   #14 (permalink)
Registered Users
 

Join Date: Sep 2011
Default

The thing about fbl is theres a chance it might think that the slower servo is wind / drift etc etc and end up overcompensating causing a crash.

At least with flybarred it will surely work to some degree.

Sent from my GT-I9300 using Tapatalk 2
__________________
Gaui X5 Formula SK720
Trex 600 EFL Pro AR7200BX
Trex 450 Pro DFC HC3SX
Blade MCPX BL
Stanley Speel is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 04:12 PM   #15 (permalink)
Registered Users
 
Posts: 3,008
 
My HF Map location
Join Date: Apr 2008
Default

For you guys that dont want to look it up:



Yes, mismatched cyclic servos and a vbar..... It can be done.
__________________
Screw It, I'm gonna fly.

In search of a 500-600 sized heli.
Preferably rtf with vbar.
povern is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 06:07 PM   #16 (permalink)
Registered Users
 
My HF Map location
Join Date: Mar 2007
Default

I agree with the advise that it's generally not a good idea to run unmatched servos on a CCPM machine. Having said that, back when CCPM was coming into fashion, servos weren't nearly as good as they are today and getting a matched set was more problomatic. The only problems you'd have however was some amount of unwanted mixing between cyclic and collective if one servo was significantly slower (or not as strong) as the rest of them were. There was a lot of discussion on the subject but in real world flying, the only time those unwanted interactions would show themselves was if you were trying to do something that required the servos to move faster than the slowest servo could move. Other than that, it wasn't an issue and the only folks that could really feel it were the top lever pilots anyway. It simply wasn't an issue for us mere mortals. Of course, those were all flybarred machines. Personally, I'd think as long as you're to the conservative side in your flying, you'll probably be Ok but I'd be replacing that servo ASAP.

Povern, what servos were on the bird in the video you posted?

Steve R.
Intrepid175 is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 06:28 PM   #17 (permalink)
Registered Users
 
Posts: 6,970
 
My HF Map location
Join Date: Oct 2008
Default

Quote:
Originally Posted by povern View Post
For you guys that dont want to look it up:



Yes, mismatched cyclic servos and a vbar..... It can be done.

for all the lazy guys of us ... thanks by the way ... I still watched the video and went to the youtube side to see what servos he uses and where he put them ...


OK nice flight video and no info about the servos used and no info about using different servos or other details. I do not say its not doable but do not expect to search for a video that does not show any details.

BTW nice flight. So what servos and where did he place them? Also did not see any straight climb out to see if they travel same speed or not. Can you correct manually for the mismatch as a good pilot - yes you can. Will a good system make proper corrections in hover - yes it will. No FBL system would overcome the speed of the servos and torque. The pilot will adjust for that. Doable - yes I agree it is. Would I recommend it as permanent solution - not really except you do not care about precision flying.


So great video but hard to see for the rest of us that this is with different servos and where they are placed or what servos are used. But we would be happy for any feedback.
im4711 is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 07:17 PM   #18 (permalink)
Registered Users
 
Posts: 2,055
 

Join Date: Jun 2012
Default

Quote:
Originally Posted by beeflyer2 View Post
I think it would be an interesting experiment. As noted above, the FBL controller should compensate and drive each servo as needed. My guess is you'd never be able to tell the difference in flight!
I totally agree, I'd be willing to bet $10 you'd never notice as the FBL controller will do all the magic behind the scenes to get it oriented at whatever angle you command it to.

On a flybarred machine it would probably go out of control and be difficult to get back to the ground.

However, as much as I want to see if I'm right, I'm not going to say "do it"!
__________________
XL Power 520 / Spektrum DX6
PcChip is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 07:22 PM   #19 (permalink)
Registered Users
 
Posts: 43,724
 
My HF Map location
Join Date: May 2008
Default

Yeah I took that video.. I don't recall mixed servos. Did Rob say that in the video at one point?

I myself would think (especially with FBL) you could get some weird wobbles going as the FBL tries to correct with the swash never moving the same speed.. could get catastrophic if is escalated.. just my thoughts.
__________________
"It's not just a hobby... it's a lifestyle" - Pete ϟ MINNESOTA!
Goblin 500 + 700 / SK540 / Jives / DX8 / Quantum / RJX servos / 306b / Deep cycles
Slyster is offline        Reply With Quote Quick reply to this message
Old 01-02-2013, 07:52 PM   #20 (permalink)
Registered Users
 
Posts: 3,008
 
My HF Map location
Join Date: Apr 2008
Default

Quote:
Originally Posted by Slyster View Post
Yeah I took that video.. I don't recall mixed servos. Did Rob say that in the video at one point?

I myself would think (especially with FBL) you could get some weird wobbles going as the FBL tries to correct with the swash never moving the same speed.. could get catastrophic if is escalated.. just my thoughts.
Pete, he doesn't say in in the video, but have you ever looked at his x5 up close? I know he flew for about a year, give or take, with different servos.

I believe his elevator was the odd servo out.

Point is, it can be done, and the fbl will compensate for it.
__________________
Screw It, I'm gonna fly.

In search of a 500-600 sized heli.
Preferably rtf with vbar.
povern is offline        Reply With Quote Quick reply to this message
Reply




Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the HeliFreak forums, you must first register.
Please enter your desired user name, your REAL and WORKING email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself. Use a real email address or you will not be granted access to the site. Thank you.
Email Address:
Location
Where do you live? ie: Country, State, City or General Geographic Location please.
Name and Lastname
Enter name and last name here. (This information is not shown to the general public. Optional)
Helicopter #1
Enter Helicopter #1 type and equipment.
Helicopter #2
Enter Helicopter #2 type and equipment.
Helicopter #3
Enter Helicopter #3 type and equipment.
Helicopter #4
Enter Helicopter #4 type and equipment.

Log-in


Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




Copyright © Website Acquisitions Inc. All rights reserved.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.

SEO by vBSEO 3.6.1