Round 2: The LAMA V4 Dual Swashplate Project : Push Pull Straight Link Bell Head - RC Groups
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Oct 25, 2009, 10:41 AM
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Round 2: The LAMA V4 Dual Swashplate Project : Push Pull Straight Link Bell Head


Revisited the Dual Swash Mod and this time with the symmetrical Bell Head Push Pull mechanism and using straight swash to mixer linkages;



This is a continuation of the original concept found here;

https://www.rcgroups.com/forums/showthread.php?t=839154


This time the linkages are symmetrical and straight despite the 90 degree shift. The link configuration follows a PUSH-PULL mechanism minimizing any slop in transmitting the swash pitch data to the upper rotor blades;




The idea is to relocate the mixing arm close to the corner of the grip allowing a straight swash to mixer ball link. The sync arm is then removed (from the original config) and relocated just above the swash using two servo link arms tucked inside the upper shaft sync forks.




Tracking test video;

* Take note of the bind free flybar and how the mixers move with the swash. Such configuration allowed me to maximize the transmission of pitch data from the upper swash to the upper rotor blades.

LAMA V4: Dual Swashplate Flybar Bell Mixing Version 2 : Tracking tests (1 min 29 sec)


Cyclic Punch Tests:

LAMA V4: Dual Swashplate Flybar Bell Mixing Version 2 : Cyclic Punches (1 min 27 sec)


Testing the heli using a short flybar;



Cyclic Punch tests using the short flybar;

LAMA V4: Dual Swashplate Flybar Bell Mixing Version 2 : Cyclic Punches with short flybar (0 min 54 sec)


Simple flight circuit with the short flybar;

LAMA V4: Dual Swashplate Flybar Bell Mixing Version 2 : Indoor circuit with a short flybar (0 min 41 sec)
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Oct 25, 2009, 10:45 AM
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The mix arm hub mechanism was derived from an old CP2 frame;



Mix arm hub trimmed and drilled a small hole for the mounting scew;



Checking the alignment of the screw;



Mixing hub mounted at the blade grip;



Mixing arm from a Belt CP / HBK2 tail rotor arm



Final config;

Oct 25, 2009, 11:37 AM
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you should patent this before the chineese steal it. and you should just break down already and make a cp coax(i know it probably isnt feasable just a thought)


CG
Oct 25, 2009, 12:02 PM
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Quote:
Originally Posted by Cable Guy
you should patent this before the chineese steal it. and you should just break down already and make a cp coax(i know it probably isnt feasable just a thought)
I hope the Chinese (or whoever) have already shamelessly stolen the plans and are working on a cheap clone so I wouldn't have to recreate what EQMOD has made.

Vas
Oct 25, 2009, 06:39 PM
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I think once it is published on a public forum, it now becomes public domain ? Not sure.
Oct 25, 2009, 06:40 PM
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A short outdoor flight. Just testing and smoothing out the linkages ;

LAMA V4: Dual Swashplate Flybar Bell Mixing Version 2 : Test Outdoor (1 min 26 sec)
Oct 25, 2009, 10:47 PM
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With so much cyclic data, you can actuall put the heli's body at an extreme angle without the need of hard acceleration and still recover from it;

Oct 26, 2009, 01:15 PM
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OK! Finally achieved a much precise and crisp cyclic control on this platform by reducing the lag on the flybar;

Punch 1

LAMA V4: Dual Swashplate Short Paddled Flybar Bell Mixing Version 2 : Cyclic Punches 2 (1 min 40 sec)



Punch 2

LAMA V4: Dual Swashplate Short Paddled Flybar Bell Mixing Version 2 : Cyclic Punches 1 (1 min 9 sec)





How was this done ? By simply adding paddles with a slight positive pitch and heavily shortening the flybar;







A positive pitch on the paddles allows for quick stabilization by applying a small amount of lift on both sides of the flybar.

As such, lag is greatly reduced and you still get the required stabiliztion despite the shortened flybar. Also with a short flybar, load on the upper rotor motor is also reduced.

LAMA V4: Dual Swashplate Short Paddled Flybar Bell Mixing Version 2 : Tracking (1 min 9 sec)


Hover stability test;

LAMA V4: Dual Swashplate Short Paddled Flybar Bell Mixing Version 2 : Stable Hover (0 min 26 sec)
Oct 26, 2009, 07:34 PM
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Outdoor video of the crisp cyclic head;

LAMA V4: Dual Swashplate Short Paddled Flybar Bell Mixing Version 2 : Test Outdoor (3 min 31 sec)
Oct 27, 2009, 03:57 PM
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Improved the head some more;

Lama V4: Dual Swashplate Short Paddled Flybar Bell Mixing Version 2 : Indoor Circuits (2 min 33 sec)
Nov 05, 2009, 03:38 PM
QuAd FaNaTiC
Razors edge 29's Avatar
awesome!
Apr 04, 2010, 11:28 PM
still running into stuff...
Constrictor007's Avatar
That thing is awesome! how can I get you to convert my Axe CX Micro
Apr 05, 2010, 04:48 AM
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Wow, you deserve a medal for even understanding the setup, let alone tuning it.

Maybe Kamov needs an engineer?
Apr 05, 2010, 04:56 PM
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This is awesome EQMOD, I've been reading most of your threads and it just blows my mind how agile these coax have become with a dual swashplate mod.

I'm currently waiting on UPS to deliver my spanking brand new Walkera 5#10 that will very possibly be joining the ranks of double swashplate machines out there.
Quick question, Do you think the shortened paddled flybar mod is better than a flybarless dual gyro design?
Apr 05, 2010, 09:12 PM
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Also EQMOD,
I've seen you talking about flybarless vs flybared setup. Does the flybarless setup flies like a FP? (ie. unless forward cyclic is corrected, it remains going forward) Or the moment you release the stick, it locks to hover (stock lama hover feel)?
How about the controls on this Link Bell Head, is it stock lama hover feel?


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