Discussion Round 2: The LAMA V4 Dual Swashplate Project : Push Pull Straight Link Bell Head

[EQMOD]

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;

http://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)

[EQMOD]

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;

[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)


CG

[VasMan]

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

[EQMOD]

I think once it is published on a public forum, it now becomes public domain ? Not sure.

[EQMOD]

A short outdoor flight. Just testing and smoothing out the linkages ;

LAMA V4: Dual Swashplate Flybar Bell Mixing Version 2 : Test Outdoor (1 min 30 sec)

[EQMOD]

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;

[EQMOD]

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)

[EQMOD]

Outdoor video of the crisp cyclic head;

LAMA V4: Dual Swashplate Short Paddled Flybar Bell Mixing Version 2 : Test Outdoor (1 min 25 sec)

[EQMOD]

Improved the head some more;

Lama V4: Dual Swashplate Short Paddled Flybar Bell Mixing Version 2 : Indoor Circuits (2 min 33 sec)

[Razors edge 29]

awesome!