Tuesday, 27 December 2011

Wallkera V200D03: Binding Issues, Tail Set Up And More...

Well it has taken a long time to get around to getting any further with setting up the Walkera V200D03 and then more time to get a blog posted on it...the run up to Xmas is always a busy time in my industry and then as for the Xmas period itself, well say no more!!!

So, first off a report on the binding process of the V200D03 flybarless collective pitch helicopter. Everything in the manual tells you that you must always turn on the transmitter first, then plug in the helicopter battery within 10 seconds.Further the throttle stick and trim must be in the bottom position before powering up the helicopter. All standard procedure I am sure you will know. The only thing is that if you do that the receiver will not pair with the transmitter, well at least not for the initial binding.

What the instructions do not tell you is that for the initial binding procedure all the switches on the transmitter need to be either up (for those on the the Tx face) or back (for those on the top).

Then, most importantly you need to reverse the switch on order; so that is connect the battery on the helicopter and then turn on the transmitter.

Yes, I was a little hesitant and cautious about doing this even though I was reasonably confident that every indication is that this helicopter has a built in fail safe that does not allow power to the motor without a transmitter signal. Then, the Devo 8 takes its time powering on, unlike I am used to with the Spektrum DX7 which is almost instantaneous. So having waited this out, hey bingo! Pairing successfully completed.

So, that completed I could then move on to checking out the helicopter set up. Mostly it was fine and probably only needs fine tuning to my personal flying preferences. One thing that did strike me was that for just a small rudder command the tail servo was travelling to its full extent. Now the question is: is this the full range of travel of the servo or is its travel being limited by the physical range of travel of the tail rotor sliding sleeve. If this is the case it will be stalling the servo and placing a strain on it. Such loads can dramatically shorten the life of the servo. I must say that I could not hear the servo stalling even when full left or right rudder was applied from the transmitter.

The other issue with this is that this set up gives very sharp tail action for very small transmitter inputs. For this reason at least for initial flights while I see how this helicopter behaves in the air and to cover the possibility of servo stalling until I have checked this out further I prefer to adjust this.

There are a couple of options here:

  1. Through the receiver/gyro reduce the Rudder Ext. Adjusting it to the full -ve value lead to little difference to reducing the effect.
  2. In combination with 1, through the transmitter Servo Travel screen reduce the extent of the rudder travel. The value required to prevent the servo reaching its limit of travel by the tail rotor sliding sleeve was actually 30% left and right. This is a very low value and leads me to the conclusion that the servo is not stalling, Walkera would not set it up like that.
  3. Another option is to relocate the tail servo bell crank on the servo bell crank in a hole nearer the centre.
  4. A further approach is to add exponential to the rudder through the transmitter setup screen. This will not actually reduce the overall travel of the servo but it makes it less sensitive near the centre of the stick so that larger stick commands will be required to produce the same same movement.

 The final setup I chose here will take a little trail and error experimentation; and it is likely that it will be a combination of several of the above, at least 1, 2 and 4. I will just have to see how sharp the tail action is in flight and adjust accordingly. The problem with 2 above is that if you reduce the rudder servo travel too much through the transmitter it can make the servo movement very sluggish in some set ups.

Moving on:

Christmas is a time for giving so just a quick suggestion to remember those selflessly working at this time for us, especially those in the emergency and medical services. Many of us heli maniacs I know have an interest in air ambulance services, which are all funded by voluntary contributions from the public. It currently costs around £1000 a flight when one of these are called out and the work that these crews do is invaluable, so if in these thrifty times if you do have even a little to spare consider contributing it to a cause like this.

Alternatively, there are other ways that you can get involved with supporting your local  (or any regions for that matter) air ambulance service. Many R/C helicopter clubs are involved with raising funds in one way or another and some hold specific events to do so. One such, that you may consider getting involved with is the RCHA Fun Flyin' at Lincoln where they raise money for the Lincolnshire & Nottinghamshire Air Ambulance For the last two years they have attempted to break the world record for the most R/C helicopters hovering simultaneously. As far as I am aware they still have the Guinness Book of Records world record. It is a great fun day and very well attended, including by some very top names.

Here is a video from the 2011 event:

I will follow up with details of this years event when they become available.

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