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Master CP - Training Gear or No?

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Old 04-18-2014, 06:55 PM
  #1
Hedgewarden
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Default Master CP - Training Gear or No?

I am a fairly good (intermediate level?) pilot of FP Helis. I have a Master CP that I wish to transition to.

I added training gear, and on my first "flight", trying to scoot around on asphalt, the heli immediately rotated over the forward training gear balls and sanded the blades on the asphalt. In retrospect, I had wiggled the cyclic to test tx-rx connection before trying to lift up - I since read that with FBL birds, that can leave the servos locked at limits - the swash was definitely tilted forward after I removed power. It was quite level when I tested it on the bench (with rotor power disconnected.)

On the second "flight", I discovered I had insufficient downward pitch when a gust of wind lifted the heli and tilted it to the right, despite my having pulled the throttle to min. I since changed the low end pitch on "Normal" flight mode to give a little negative pitch. The blades got a few tenths of millimeters shorter again.

The third flight, the heli wanted to tilt forward again, rotating on the the forward balls of the training gear. No contact this time since the additional negative pitch let me pull it back level on the ground, but I'm still not able to make a clean launch to a low hover.

On the test stand, the bird will tilt according to the cyclic just fine.

I am tempted to remove the training gear and move to grass - and let the crashes happen if the bird does not respond in Normal flight mode similar to an FP. At present, the throttle and pitch curves are set to some recommended "beginners" settings, with restricted ranges. Cyclic axes have no restrictions.

Eqmnt: Master CP and Devo 10.

Experience: WLToys V911, and V912, with which I am proficient enough to crash only when trying a new stunt, like flying through a box (V911) or the wind gusts and I lose some control of the V912 - which is almost identically the same size as the Master CP.

What are the thoughts about removing the training gear? Are CP helis in "NORMAL flight" mode REALLY that much different than FP helis? If so, how so?

Thanks for any help.
-Howard
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Old 04-22-2014, 04:43 PM
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Hedgewarden
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Follow-up: Taking hints from a few things I have read, I decided to give up"scooting" the Master CP around on its training gear and try a direct take-off from grass.

It lifted fairly well, and was generally controllable, except that it seemed to struggle with the weight and rotational inertia of the training gear. Then, after a minute or so of hovering at about 1-2 feet, it started oscillating in roll and pitch axes with NO control inputs. Landing was accomplished without crash only because the training gear rotated the chopper to upright in a very awkward touch-down.

So, my conclusion is that training gear is NOT compatible with the 6-axis stabilization in the Master CP - the loop gain or time constants are NOT able to handle the additional rotational inertia of the training gear.

My second conclusion is that, despite all the dire warnings that CP is a huge step from FP - e.g. that "everything" I learned flying FP needs to be forgotten and relearned for CP - may be over-blown for "Normal Flight" mode. Of course, stunt mode and 3-D flying is obviously going to be a whole different world - one which I plan to attack on a simulator. In the mean time, I am excited to start practicing normal mode flying with a "beginner's CP" to experience how the 6-axis stabilization is going to make precision flying more fun. My base for comparison is the WL Toys V912 - which is almost identically the same size, but has only yaw stabilization and judging from battery specs, about 1/2 the power of the Master CP.

Of course, once I get more than 60 seconds of air time, I may have to retract all optimistic attitudes.

Please temper all my conclusions with the fact that I am still posting noobie questions.

=Howard

Last edited by Hedgewarden; 04-22-2014 at 04:46 PM. Reason: Clarification
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Old 07-13-2014, 08:55 AM
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dchin62973
 
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Fixed Pitched (FP) Helicopters are designed with only (2) servos to control cyclic movements. With a Collective Pithed (CP) Helicopter, there are (3) servos that control the cyclic movement. The extra servo controls the PITCH of the blades on the helicopter. So, the design is totally different as adjustments to the cyclic servos have to be made properly before flying. If you have a crash, linkages and servos must be replaced. A defective cyclic servo can cause more problems when flying. An improperly ball linkage can cause instability and poor blade tracking causing power loss when throttling the helicopter up.

Essentially both FP and CP Helicopters fly the same in NORMAL Mode. CP Helicopters have a STUNT Mode as the architecture allows for negative PITCH on the blades achieved through the PITCH Servo (Third Servo). Consider a digital pitch gauge to balance the PITCH of your blades on the Walkera Master CP. Align sells the AP-800 Digital Pitch Gauge and TAROT sells a lower cost brand.

http://youtu.be/K-T3BkulkAg

-Dane,
Sales@rtf-heli.com
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