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Borneoben · 01-06-2010, 10:46 AM

Hi Guys

I have an interesting question for you.

I know that Damping in FBL heads is a hot topic, some people have good results with rigid heads and some swear by Damping.

However, how about flapping hinges on a scale multibladed head?

I am planning on a Multiblade FBL head for a scale project with a SK360 for stabilisation duties but i am concerned about potential oscillation problems.

Any advice greatly recieved

Cheers
Ben

Borneoben · 01-10-2010, 07:53 AM

Wow I'm amazed no one has an opinion on this?

Im considering installing the head without the SK360 and seeing how it flies first. As i really want to put it onto another heli.

Any thoughts guys i would appreciate it.

Ben

kazager · 01-11-2010, 05:57 PM

Maybe post it in Scale too?

whaleboy · 01-12-2010, 01:11 AM

Am I alone in not having the slightest idea what a "Flapping Hinge" is?

-David

rickn816 · 01-12-2010, 09:35 AM

Quote:

Originally Posted by Wazzer

Wow I'm amazed no one has an opinion on this?

Im considering installing the head without the SK360 and seeing how it flies first. As i really want to put it onto another heli.

Any thoughts guys i would appreciate it.

Ben

No. It will not work. Sorry. The FBL system relies on feedback from the blades to send the next set of instructions through the servos to the swasy. When you hinge the blades, you lose the feedback and the heli will crash.

There is a thread on RCGroups about this. He lost his machine. Total loss.

Rick

SidewaysLS4 · 01-12-2010, 11:19 AM

I have a CopterX super-flappy 4 blade head with a Sk360 and it works pretty good. Hasnt crashed yet.

rickn816 · 01-12-2010, 03:31 PM

Quote:

Originally Posted by SidewaysLS4

I have a CopterX super-flappy 4 blade head with a Sk360 and it works pretty good. Hasnt crashed yet.

Lucky. The manual states you need a rigid head.

Rick

SidewaysLS4 · 01-12-2010, 03:45 PM

I wouldnt say "need" a rigid head, just that stiffer dampers work better. For scale apps...not all that important IMO, at least with my experiences.

Lets see what the manual says...

How stiff the rubber rotor head dampers are will have an effect on tuning the gyro
and flight performance. Performance will be better with the teeter damping a stiffer
than normal, but too stiff can cause vibration, which is hard on the airframe, gyros,

and servos.

rickn816 · 01-13-2010, 12:41 PM

Quote:

Originally Posted by SidewaysLS4

I wouldnt say "need" a rigid head, just that stiffer dampers work better. For scale apps...not all that important IMO, at least with my experiences.

Lets see what the manual says...

How stiff the rubber rotor head dampers are will have an effect on tuning the gyro
and flight performance. Performance will be better with the teeter damping a stiffer
than normal, but too stiff can cause vibration, which is hard on the airframe, gyros,

and servos.

OK. Damped, but not flapping hinges.
Rick

SidewaysLS4 · 01-14-2010, 04:20 AM

Rick, your thoughts on a fully flapping hinge head while spooled up with centripetal forces pulling the blade assembly rigid much like a damped head?

I'd also like to know if you recommend torquing down the blade screws to eliminate any lead/lag flapping.

jvthert · 01-14-2010, 11:09 AM

Lead/ lag is essential. You should never tighten your bladegrips to prevent it.

rickn816 · 01-14-2010, 08:35 PM

Quote:

Originally Posted by SidewaysLS4

Rick, your thoughts on a fully flapping hinge head while spooled up with centripetal forces pulling the blade assembly rigid much like a damped head?

I'd also like to know if you recommend torquing down the blade screws to eliminate any lead/lag flapping.

Page 6 of the 2008 manual:

"Performance will be better with the teeter dampening a stiffer than normal, but too stiff can cause vibration."

I followed a thread on RCGroups involving a scale Agusta. He had flapping hinges, and the machine crashed. The unit depends on feedback from the blades. The flapping hinges remove that feedback. Lead-lag is not an issue. I would set the screws as you would with a flybar.

Rick

SidewaysLS4 · 01-14-2010, 10:58 PM

Wow, I gonna have to find that and see what happened. Kinda intreguing considering how my CopterX "it doesnt get any flappier than this" 4 blade head and SK360 get along so well together in flight.

kennethw · 01-14-2010, 11:22 PM

You might want to talk to Super-Hornet, he has a few Multi-Blade flapping hinge heads coupled with the SK360, all fly perfectly.

SidewaysLS4 · 01-15-2010, 08:31 AM

Got a link to that e-stabilized crash because of a flapping head thread? I cant find it.

rickn816 · 01-15-2010, 05:58 PM

Quote:

Originally Posted by SidewaysLS4

Got a link to that e-stabilized crash because of a flapping head thread? I cant find it.

Start reading here.

Rick

http://www.rcgroups.com/forums/showt...808224&page=18

SidewaysLS4 · 01-16-2010, 09:26 AM

Yeah, that is a weird one. Violent pitch on small stick movement was interesting. I have my 450 flapper head running 90*/sec in the SK with 1650rpm headspeed, and on brain-fart occasions had the opportunity to full-stick it with 27% Bell rates...and it followed commands precisely. I dont know what happened with his heli, whether he still was running 1000 rpm headspeed which might have turned natural heli response to mush (just saw that on the 1st page, maybe he sped it up a bit). I have 0 experience with the bigger stuff, so I dont know how that speed is however. Kind of strange reading his experiences, somewhat different from what I've been having with the SK.

I can say though, on a fully flapping 450 4 blade head, the SK360 performs admirably, and reports indicate others have the same experience.

01-06-2010, 10:46 AM	#1 (permalink)
Borneoben Registered Users My HF Map location Join Date: Feb 2005	Flapping Hinges and Electronic Stabilisation, Good Idea? Hi Guys I have an interesting question for you. I know that Damping in FBL heads is a hot topic, some people have good results with rigid heads and some swear by Damping. However, how about flapping hinges on a scale multibladed head? I am planning on a Multiblade FBL head for a scale project with a SK360 for stabilisation duties but i am concerned about potential oscillation problems. Any advice greatly recieved Cheers Ben

01-12-2010, 01:11 AM	#4 (permalink)
whaleboy Registered Users My HF Map location Join Date: Nov 2007	Am I alone in not having the slightest idea what a "Flapping Hinge" is? -David __________________ Trex500 sk360 \| Logo400 vbar \| Logo500 vbar \| logo 600se vbar \| Synergy N9 sk360 \| E-Aurora vbar \| Mini Protos beastX \| mcpX

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01-10-2010, 07:53 AM	#2 (permalink)
Borneoben Registered Users Thread Starter My HF Map location Join Date: Feb 2005	Wow I'm amazed no one has an opinion on this? Im considering installing the head without the SK360 and seeing how it flies first. As i really want to put it onto another heli. Any thoughts guys i would appreciate it. Ben

01-11-2010, 05:57 PM	#3 (permalink)
kazager Registered Users Join Date: Apr 2009	Maybe post it in Scale too?

01-12-2010, 11:19 AM	#6 (permalink)
SidewaysLS4 Registered Users Join Date: Apr 2009	I have a CopterX super-flappy 4 blade head with a Sk360 and it works pretty good. Hasnt crashed yet.

01-12-2010, 03:45 PM	#8 (permalink)
SidewaysLS4 Registered Users Join Date: Apr 2009	I wouldnt say "need" a rigid head, just that stiffer dampers work better. For scale apps...not all that important IMO, at least with my experiences. Lets see what the manual says... How stiff the rubber rotor head dampers are will have an effect on tuning the gyro and flight performance. Performance will be better with the teeter damping a stiffer than normal, but too stiff can cause vibration, which is hard on the airframe, gyros, and servos.

01-14-2010, 04:20 AM	#10 (permalink)
SidewaysLS4 Registered Users Join Date: Apr 2009	Rick, your thoughts on a fully flapping hinge head while spooled up with centripetal forces pulling the blade assembly rigid much like a damped head? I'd also like to know if you recommend torquing down the blade screws to eliminate any lead/lag flapping.

01-14-2010, 11:09 AM	#11 (permalink)
jvthert Registered Users My HF Map location Join Date: Mar 2007	Lead/ lag is essential. You should never tighten your bladegrips to prevent it.

01-14-2010, 10:58 PM	#13 (permalink)
SidewaysLS4 Registered Users Join Date: Apr 2009	Wow, I gonna have to find that and see what happened. Kinda intreguing considering how my CopterX "it doesnt get any flappier than this" 4 blade head and SK360 get along so well together in flight.

01-14-2010, 11:22 PM	#14 (permalink)
kennethw Registered Users Join Date: Feb 2009	You might want to talk to Super-Hornet, he has a few Multi-Blade flapping hinge heads coupled with the SK360, all fly perfectly.

01-15-2010, 08:31 AM	#15 (permalink)
SidewaysLS4 Registered Users Join Date: Apr 2009	Got a link to that e-stabilized crash because of a flapping head thread? I cant find it.

01-16-2010, 09:26 AM	#17 (permalink)
SidewaysLS4 Registered Users Join Date: Apr 2009	Yeah, that is a weird one. Violent pitch on small stick movement was interesting. I have my 450 flapper head running 90*/sec in the SK with 1650rpm headspeed, and on brain-fart occasions had the opportunity to full-stick it with 27% Bell rates...and it followed commands precisely. I dont know what happened with his heli, whether he still was running 1000 rpm headspeed which might have turned natural heli response to mush (just saw that on the 1st page, maybe he sped it up a bit). I have 0 experience with the bigger stuff, so I dont know how that speed is however. Kind of strange reading his experiences, somewhat different from what I've been having with the SK. I can say though, on a fully flapping 450 4 blade head, the SK360 performs admirably, and reports indicate others have the same experience.

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