Saturday, 3 March 2012

mCPx Update and more...

Well after the main frame replacement I thought I would give a very quick update.

Having completed the replacement of the main frame I had left it that I had levelled the swashplate by eye with final adjustments to be made using the trims if necessary.

Well when I took it out the other day, we finally got a window in the weather in my little corner of the UK, I expected to be having to make trim adjustments but to my surprise everything was spot on and the little heli flew like a dream straight off, which was very pleasing.

Now for those of you who are longing for the Summer and, hopefully, long days of good flying weather here is just a teaser of a little Italisan sunshine:

 For some at least the 2010 Heli Smackdown clearly went with a real splash!!!

I hope that cheered you up if you have been suffering from Winter blues. On the optimistic side, and I like to think of myself as an optimist, the great thing about this time of the year is that we have the whole of Spring and Summer to look forward to. Here in the UK, this week we have a little tempting glimpse and a few signs that Spring is just around the corner. During the day we have had some pleasantly warm sunshine and believe it or not on March 1st I actually got a chair out and had my lunch sitting out in the garden...a first for this year at least!

I hope you all enjoy a great Spring and Summer, with lots of great fying weather, wherever in the world you may be.

Well after the main frame replacement I thought I would give a very quick update.

Having completed the replacement of the main frame I had left it that I had levelled the swashplate by eye with final adjustments to be made using the trims if necessary.

Well when I took it out the other day, we finally got a window in the weather in my little corner of the UK, I expected to be having to make trim adjustments but to my surprise everything was spot on and the little heli flew like a dream straight off, which was very pleasing.

Now for those of you who are longing for the Summer and, hopefully, long days of good flying weather here is just a teaser of a little Italisan sunshine:

 For some at least the 2010 Heli Smackdown clearly went with a real splash!!!

I hope that cheered you up if you have been suffering from Winter blues. On the optimistic side, and I like to think of myself as an optimist, the great thing about this time of the year is that we have the whole of Spring and Summer to look forward to. Here in the UK, this week we have a little tempting glimpse and a few signs that Spring is just around the corner. During the day we have had some pleasantly warm sunshine and believe it or not on March 1st I actually got a chair out and had my lunch sitting out in the garden...a first for this year at least!

I hope you all enjoy a great Spring and Summer, with lots of great fying weather, wherever in the world you may be.

Thursday, 16 February 2012

Blade mCPx - Replacing The Main Frame

Something that I had not anticipated with the Eflite Blade mCPx collective pitch RC helicopter was the possibility that I would be replacing the main frame. Short of breaking the body mounting posts (which I had managed to break one on the Blade mSR but had repaired that with a the use of appropriate glue) there seemed little that might call for it. However, what I had not considered was that the main frame might need to be replaced not because of damage to the main frame itself but the attachment of a component to it.

Video courtesy of BrainShaw33

The damage must have occurred after a particularly heavy meeting with the ground recovering from inverted, although I must say I had not noticed it at the time as I called it a day with that unscheduled landing as I was aware that the batteries were low. The damage that had gone unnoticed initially was to the two posts that come vertically out of the landing gear to mount it in the main frame. These had both split near their base but neither had come broken clean off. It was only the next time that I tried to fly the mCPx that it became apparent that something was amiss as the helicopter was very unstable and pretty quickly came down. Close inspection then revealed that one of the posts had broken off while the other was near to doing so. Not of itself a problem, just pick up a new set of landing skids and you are away again. 

 When you realise that the post has broken off right at the base with the post itself still wedged in the main frame things are not so straightforwards; at least not when you discover that the little plastic post can not be coaxed out by pulling or levering it and is even resistant to any attempts to drill it out.

At that point the only remaining option is to get a new main frame as well as a new set of landing skids.

So a few days later the items have arrived - together with one of the new tail rotor blades for the V2, which I thought I would get to try while I was ordering. These have a wider blade with a greater pitch angle on it to provide better tail holding capabilities, or so they claim.

So with all parts at the ready I proceeded to set about the job of changing the main frame. You will need good light and if your eyesight is not 100% then probably a magnifying glass as the parts are tiny. Neither is it a job for anyone who is all thumbs!

The first step is to remove the tail boom and disconnect the tail motor plug from the main board. The boom comes free without too much trouble if you give it a sharp pull. I recommend that you first unplug the tail motor because giving a sharp pull on the tail boom can lead to it jolting away quite rapidly leading to you yanking the cable from the tail motor to the main board. The result may be damage to the wiring or the plug.

That done and the canopy removed I moved onto removing the main shaft. If you take the main gear off and disconnect the 3 pushrods from the swashplate the main shaft will then lift out complete. It is also necessary to remove the top and bottom bearings from their housing in the main frame. It is wise to note which way round they sit when doing so. I would describe them as having a closed side (has larger flanges) and an open side (whereby you can see more of the bearings). In each case it is the 'closed' side which faces out when located in the main frame.

After that the servos can be removed. I left all of these plugged into the main board. This seems to be the simplest option but alternatively you could unplug them, having first clearly marked which one goes where. I also left the servo pushrods in their respective servos, although these can quite easily drop out.

The first servo that I removed was the elevator servo, located to the rear of the main frame. This is actually the most fiddly of the three due to its location within the main frame, whilst the 2 lateral cyclic servos just screw onto the open sides. Each servo is located with 2 diagonally opposite x-head screws which can be easily removed with the jewellers screwdriver provided with the model. The other opposing corners are just pushed onto plastic locators on the main frame, or in the case of the 2 side servos there is only 1.

The screws are rather tiny, as can be seen in this picture, so care is needed not to lose any.

Having removed the three servos I next removed the main board. This is again held in place with 2 screws, each with their own washer so that the screws can be bedded down firmly without damaging the more fragile material of the main board. These two screws are also longer than those used to locate the servos.

Next the main motor can be unscrewed. Again two hex screws hold it in place (Note these are short, stubby screws). Then the motor can be slotted out from its quite tight housing.

That done you are left with the old main frame separated from its fixtures.

All the parts attached to the main frame are held in place by a sum total of 5 pairs of screws.

One new main frame waiting to be made up into a 3D flying machine.

Putting it all back together again in the main frame is basically a reverse of the above process of taking it apart.

I started first by attaching the main board, remembering that the copper wire from the main board wraps around the canopy support arm on the left side.

Then in goes the motor, followed by the two lateral cyclic servos. Just make sure that you get the servos on the correct side or your swash plate movements will be reversed.

When it comes to replacing the elevator servo at the rear there is a definite trick to it. It is necessary to ensure that the servo pushrod is attached to the servo BEFORE you put the servo back. There is no way to do it afterwards. Furthermore the servo pushrod has to be the right way around. The pushrod should be on the inside with the short hooked end on the outside.

Correct placement with the servo pushrod arm central and the hook to the outside.

Incorrect placement with the servo pushrod arm on the outside.

Having made sure that the servo pushrod is correctly attached to the servo the next point is to ensure that when putting the servo back in place that you lead with the servo pushrod, slotting it through the oblong plastic frame opening on the top between the upper main bearing, to the front, and the tail boom mount to the rear.

With that done the fitting of the main frame is all but complete.

All that remains now is to put the complete main shaft back on, re-attach the servo pushrods to their respective ball ends and replace the tail boom. When replacing the tail boom wrap the motor wire back along the top of the tail boom so that when the boom is pushed back into the main frame the wire slots into the grove for it above the tail boom hole.

Next ensure that the swash plate is level. The pushrods may have changed length if the ball links have become screwed on more or less in the process. Further, there is no guarantee that the two mainframes will be identical and if the servo locations are slightly different the servo pushrod lengths will need to be changed. It is then a matter of attaching a LiPo to provide power in order to centre all the servos. The length of the various servo pushrods, respectively, can then be changed as required by screwing the ball links on or off a turn or so until the swash plate is level in all orientations.

If unable to get the swash completely levelled by eye by adjusting the pushrods, as these may not make fine enough changes on such a small helicopter, then it can be fine tuned using the sub-trim of the transmitter (if using a radio like the Spektrum DX6 or 7) or if using a lower specification transmitter that does not have this you will have to adjust it with the trims.

All that then remains is to check that all the controls are operating the swash in the correct directions and take a test flight to making any final adjustments to the trims.

So what was the cost of this?

BLH3505 Main Frame w/hardware           £4.99
BLH3504 Landing Skid & Battery Mount  £4.50
Total cost                                                  £9.49

I also fitted a new style tail rotor as mentioned before, BLH3603 £1.50

Now how does that compare with the cost of accident repairs on say a 450 size helicopter? Probably 5 to 10 times cheaper; plus there are alot less parts to break, it is very much more resilient to crashes and so much more straight forward to repair (if you can handle the tiny size of everything!). The only tool that I needed to use throughout was the provided jewellers screwdriver.

It is no wonder that these little micro-size 3D RC helicopters are becoming so popular!

So is the Blade mCPx the only real choice in this niche of the RC helicopter market!

Absolutely not. Here are 3 other major contenders from Walkera worthy of more than just serious consideration:
                     - The Walkera Genius CP

 - The Walkera Mini CP: this one you don't even need to pick up when it crashes!!!

                                                                                               - The Walkera V120D02S

I will be doing in depth reviews of these on these in the coming weeks.

Keep flying, and ENJOY!!!

Saturday, 4 February 2012

LiPo Batteries: All You Need To Know

Walkera V450D01 inverted hover (grass cutting!)
If there is one thing that has helped the hobby of flying RC helicopters explode to its current popularity it has to be the develoment of the LiPo battery, largely as the result of the drive to produce small light rechargeable power sources for the mobile phone industry. With not only their size and weight characteristics but also their power output and storage capacity being very favourable for use in RC flying models, where the power to weight ratio is so critical, everything was set for electric powered models to make huge strides forward. Whilst the only viable power source had been nitro/gas engines the hobby was always going to remain limited to the more serious enthusiasts; largely because of the generally perceived difficulty, messiness and expense of these models. Furthermore, the required size and noise of these models restricted when and where they could be used. With the rise of the LiPo battery the way was paved for electric powered RC helicopters and planes to rise to the fore and make the hobby much more widely accessible. Once radio controlled helicopters were able to enter the toy market the real surge in interest in the hobby side inevitably followed and from that rise in popularity we have seen not only a much wider range of manufacturers in the market but also manufacturers who have the financial means to invest in driving technological developments forward whilst dropping the prices of advanced products still further for the consumer. So the benefits of the advent of the LiPo battery have been wide ranging for the RC helicopter hobby.
Electric RC helicopters now have the power to perform the most amazing aerobatics even in large size models

LiPo’s, or more correctly Lithium Polymer, batteries are the most common way today of powering electric RC models. Planes and helicopters are biggest beneficiaries of the development of LiPo batteries because they are very light in weight compared to the amount of energy they can store. They also have high discharge rates compared to conventional rechargeable batteries (NiCad or NiMH) enabling them to provide the huge bursts of power required by high performance motors used in extreme flight manoeuvres. It is the innovation of the LiPo rechargeable battery that has enabled electric power to become so popular for RC helicopters, brought the cost down and opened the wonders of flying RC helis to a much wider audience who would never otherwise have entered the hobby.

The latest micro-technology together with the advent of LiPo batteries has enabled palm-sized Rc helicopters to be developed, now with highly agile performance, such as this 6-Channel RC helicopter from Walkera.

For all their advantages there are a few downsides to LiPo’s; namely their relatively high price, whilst having a lifespan that is quite limited. You need to care for them properly if you are going to get even 300 – 400 cycles out of them. In order to do this you need a little knowledge on how to care for them (another article needed for this). There is a degree of hazard involved with LiPo’s, the volatile electrolytes have been known to catch fire. This is not something that I would overplay but it is something that you need to be aware of and should always be kept in mind.
The risk of LiPo fires are sometimes overplayed but it should never be forgotten!
There are a few numbers on LiPo batteries that you need to particularly look out for, which determine its rating and suitability for your particular model. The main ones are the batteries voltage (V), its capacity (mAh) and its discharge rate or ‘C’ rating.

Confused by all the numbers listed for a LiPo?

So, the first of these – voltage (V). LiPo battery packs are built up of cells each with a voltage of 3.7v. Those used in radio controlled helicopters, planes and the likes will normally be 1 to 6 cells each of 3.7v. LiPo’s will normally state the number of cells (S) but do not always show the voltage. So a 1S pack will be 3.7v, a 2S pack is 7.4v and a 3S pack 11.1v, right the way up to a 6S pack at 22.2v. Why is ‘S’ used to represent the number of Cells? Well it is the number of cells in Series and ‘C’ is used to represent the discharge rate. Ok, ‘C’ for Discharge rate! Makes sense! Well actually there is sense in it as the discharge rate is a factor of the Capacity of the cell. This will all become clearer later. If there are a number of cells in Parallel this will be given a ‘P’ number, but other than very large capacity LiPo’s packs are usually 1P. So you might see “3S 2P” written on a LiPo, indicating that there are 2 lots of 3 cells in series hooked up in parallel.
The important thing though with voltage is simply to ensure that you have the correct voltage LiPo’s for your particular model. This will be determined by the motor and speed controller combination of the model. You simply follow that. So if it states you need an 11.1v 3S LiPo you get just that for your model. The capacity and discharge rate of the LiPo’s can be easily varied but the voltage must be right.
That then leads nicely on to deal with LiPo capacity. This is usually given in mAh (milliamp hours). This quantifies how many milliamps you could drain from it at a constant rate for an hour in order to fully discharge the pack. Thus if you could run a LiPo at 2200mA for an hour its capacity would be 2200mAh and it would have twice the capacity of a LiPo that could run at only 1000mA for an hour in order to completely drain it from fully charged. It is like the size of the fuel tank in your car. Obviously the larger the capacity of your fuel tank, or LiPo battery, the longer you can run for. With radio controlled models, especially RC helicopters and planes, the limiting factor is the weight and size of the battery pack. A larger capacity pack may give you longer flight times but being heavier it will adversely affect performance.
So now for the discharge rate (C). As noted before the ‘C’ is related to the capacity and here is how. The C number represents how many times faster than the Capacity you can discharge the pack safely at a constant rate. So a 2200mAh LiPo with a 20C rating can be safely discharged at up to a sustained load of 44000milliamps (44amps). From this you can also determine how long it would take to totally discharge the pack at that load. Since the capacity of a pack is quantified by how many milliamps it will take to totally discharge it in an hour, the time it will take to drain at the C rate will be 1 hour, or 60 minutes, divided by the C value. So a 2200mAh pack with a 20C rating would discharge in 3 minutes. In practice we never constantly apply anything like these levels of sustained discharge so the flight times a much longer.
Many packs will now show two figures for the capacity, eg 20C/40C. The first of these represents the constant discharge rate discussed above and the second the ‘burst rate’. As you might guess from the name the burst rate denotes the discharge rates for short bursts. 

Some manoeuvres require short bursts of high power. 
Pictured is the amazing Walkera V120D02S performing 3D

There are a number of factors to keep in mind when selecting the C rating for your batteries. Firstly it should be noted that in general the higher the discharge rate the more expensive the LiPo, although the difference is getting less. Secondly, you cannot use one that is too low; which would damage your pack and quite possibly ESC. For beginners and light sport or scale flyers with RC helicopters up to a 450 size 20-25C is ample. When you start doing more aggressive 3D manoeuvres or using bigger helicopters you need to look at stepping up to 35-45C rated packs. The best advice here though is that if you can afford to do so you should go for a little more than you need. A LiPo pack running close to its limits will get hot and this shortens its life. So you may pay more for a more generous C rating but it is likely to last you longer. A tip here is to test the temperature of your LiPo’s immediately after landing. If it is too warm to comfortably hold tightly in your hands then the pack is getting too hot. This means that either you need a higher C rated pack or your pack is getting old and needs replacing.
LiPo’s will also be overheated by running them too long. Never ever run them to a standstill. As they run down the voltage drops and the internal temperature rises, with 3 volts per cell being the critical point at which they become overheated and potentially damaged. Often quoted is the 20% golden rule. That is, you always have 20% of the LiPo’s capacity remaining at the end of the flight (Sometimes you will see this written as the 80% rule – obviously this being that you should not drain more than 80% of the capacity).  So a 2200mAh pack should always have a minimum of 440mAh remaining. A good digital charger will show you these figures. If you hook it up after a flight it will give you the capacity remaining in the pack and you can also read the voltage of each individual cell. Alternatively you can measure the voltage of the whole pack with a digital voltage meter. Look for reading of more than 3.75 volts per cell (ie 3.75 x the number of cells in the LiPo pack). So that would be 11.25v for a 3S pack. 
Conversely, at the other end of the scale you should never overcharge a LiPo. A 3.7 volt per cell LiPo is fully charged when it reaches 4.2 volts. Beyond this again it will overheat, shortening its lifespan and potentially they can set alight as the electrolytes they contain are volatile. A good quality charger which measure this and you will be safe so long as you set the correct number of cells or voltage on the charger (the correct voltage to select will be 3.7 x the number of cells in the LiPo pack).
It is also important to get the charge rate correct in order to maximize the life of your LiPo’s. Until recently this was always no more than the capacity of the LiPo (So a 2200mAh LiPo could be safely charged at a current of 2200mA). Now an increasing number of manufacturers are indicating that better quality packs can be charged at rates of 2-3 times the capacity or even more in some cases. The best advice here is to follow the advice given by the manufacturers of the brand that you purchase. The advantage of course of charging at a higher rate (current) is that the pack charges quicker; which equals less waiting time and more flying time.
Next it is important to balance a pack after charging. This ensures that every cell in a multi-cell pack has the same voltage. Your charger reads the total voltage across the whole pack, so that if it is set to charge a 3 cell pack it will stop charging when the voltage reaches 12.6 volts (3 x 4.2 volts). Now obviously that does not mean that each cell has 4.2 volts. One cell could have charged faster than the other two and have reached a higher voltage, and as discussed above it is critical that a cell does not get charged beyond 4.2 volts. Therefore, the pack should be balanced using a balance board, or today many better quality charges have a balance socket so that this can be done whilst charging.  
Charging using a 'blinky'

Alternatively, you can use a ‘blinky balancer’ which you can purchase separately if your charger does not have the facility. Cheaper balance chargers achieve the same effect through charging through the balance plug on the LiPo, but as this has narrow gauge wire only capable of taking a low current charging has to take place more slowly.

Charging through the balance plug

Finally a word on safe charging. It is always stated that you should never leave a LiPo unattended whilst it is charging. Since this is not very practical to stand watching them the whole time the following safety precautions are recommended. Firstly, check your LiPo’s regularly until the charge cycle is complete and never leave the house (preferably stay in the same room) during this time. It would be courting disaster to leave them whilst you go out and likewise do not go to bed with them still on charge, even though you know your charger will stop when they are completely charged. Charge your batteries in a fire proof container. The purchase of charging bags is highly recommended. Preferably charge your LiPo’s in a room fitted with a smoke alarm. Or even better buy one especially to site above where you recharge your batteries.

Look after your LiPo’s and they will repay you with good sustained performance over a long period of time. Charge safely and you will enjoy many years of flying.

 The power of electric flight - go anywhere, anytime - and now even fly onboard with FPV

Saturday, 31 December 2011

Blade mCPx: Further Adventures (or should that be 'Misdemeanours'!)

Well here in the midst of the British winter outdoor flying days have been few and far between...and on the few decent days we have had over the last few weeks it seems that I just haven't had the opportunity to get out flying - business takes priority this time of the year. Then add to that the short day length in the UK at this time of the year.

At last on Monday of this week I did manage to get the chance to pack my bag with the mCPx and Spektrum DX7 and head off down to the flying field and put a couple of packs of lipos through...yes, that reminds me - when it comes to lipos for the mCPx do invest in as many packs of the Turnigy nano-tech 300mAh 35C batteries as you can. They fit the Blade mCPx without modification, the extra capacity of the 300mAh gives you longer flight time and being 35C you get the extra zip you really need to get this little heli moving. It really is needed for 3D flying and really for any type of flying where you have wind to contend with. (If these figures leave you bemused then take a look at the RC Helicopter Fun website - it's loaded with information and he gives you easy to understand and in depth rundowns depending on the level you want. For the ABC on lipo batteries click HERE ).

It was not a still day by any means but we actually had some bright sunshine - not always helpful this time of the year as it is so low in the sky, so you have to keep it in mind when flying. One of the nice things about the mCPx for someone starting out with a collective pitch helicopter is the smooth transition when on standard setting between the 3 flight modes (if using a DX7). Of course its stability and resilience to crash impacts are huge reasons to favour it, plus the fact that it is generally just a great helicopter that no matter what you level of competence (once you have at least a small amount) you can always get something out of this little heli...and largely that something is loads of fun. Plus it is a heli that just grows with you as you grow with it.

Now this day was one when i was going to test the resilience of the mCPx - not by design. Flying it round first getting the feel of it again after not having been out with it I thought I would have a go at some new inverted manoeuvres I have been practicing on the flight simulator - the result a couple of heavy power on impacts into the ground, fortunately nice soft grass after all the rain we have had. It is actually quite a smart move finding some grass to fly over when your starting or trying out something new. The result of the impacts, well it through the main gear as usual...just a push back on job and off we go again. The second impact did result in breaking the canopy and a piece came clean off, while part was retained by the canopy supports. Here are the pictures:

Right side: as it should be.
Left side: with the crash modification

You can see what a tidy job I made of the modification. I certainly shall not need to rush out to buy a order a new canopy...and it flies fine still, so no other damage done.

Back to the flight sim for more practice I think!!!

To finish this post off I thought I would just add a note on the importance of a correctly set up swash plate in order to get a collective pitch helicopter to be a pleasure to fly rather than a handful. Below are pictures taken of the 450 size helicopter I am finishing off show how a swash plate should look:

Low Stick Position - Swash at Lowest Point
Mid Stick - Swash at Middle of Range
High Stick position - Swash at Highest Point
Note how the swash plate is nice and level throughout the full range of its movement. Regardless of where the left throttle/pitch stick on the transmitter is the swash plate stays level as it moves up and down with the stick movements.

To finish off with...a teaser video...

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.

Monday, 5 December 2011

Walkera V200D03 - Setting Up The Devo 8 Transmitter

In the unboxing review of the Walkera V200 D03 I stated that I was going to report on how I found programming the Devention 8 transmitter included in the package. So, here is that rather overdue report.

The Devo 8 is really easy to programme. Everything is very intuitive and very easy to find. I was very pleased with the touch screen, it was sensitive enough without being over sensitive and it does make it much quicker and easier to navigate than conventional means via buttons or buttons and scrolling mechanisms.

Nearly everything was already set as per the V200 D03 manual. The setting programmed in give a good starting point for general flying and advanced aerobatics. From these they can be fine tuned to individual preference. They can be smoothed out to tame the helicopter down for novice pilots (together with adjustments made to the receiver/gyro unit) or it can be tuned up for more aggressive 3D flying. All the parameters that you want can be readily adjusted, and it is so easy to do so with the new touch screen.

The only settings that I initially changed were the Power Amplification (which was set to the maximum +20 dBm, where the manual recommends it to be set at 0 dBm), the sound (personal preference, I’m not a fan of it bleeping at me every time I press a button so I turned it off) and then finally I activated the throttle hold. As provided the transmitter is set up for the Rudder D/R switch to control the rudder dual rates. I changed it to operate the throttle hold. I like to have this function:

1)      for safety, so that I know I’m not going to power the main blades accidently at the wrong time
2)      if an RC helicopter crashes in idle up mode (Flight Modes 1 and 2, or stunt mode as it is otherwise known) then you want to quickly be able to cut the power to the rotors to minimise damage. Again, that is a personal choice but one that is widely followed.

A feature of the Devo 8 that I really love is the ability to change the gyro sensitivity at the flick of a switch. Above the cyclic (aileron/elevator) stick on the right side, by the Aileron Dual Rate Switch is a 3 position Mix Switch.
This allows you to select between 3 pre-set gyro sensitivity settings. These are factory set at:

·         Pos 0: 75%,
·         Pos 1: 70%,
·         Pos 2: 40%.

The higher the percentage the more sensitive the gyro is and the faster it will react to movements of the helicopter not resulting from stick inputs. Thus the lower the percentage the softer the response of the helicopter and the more stable it will be in the air. The beauty of this is that if for example the wind picks up you can easily reduce the gyro sensitivity to increase stability in the wind and make it more flyable.

 Alishanmao demonstrates use of Gyro Gain Switch in the wind

It also means that as your flying skills improve you do not necessarily have to start making adjustments to the receiver/gyro itself to allow you to progress to more agile helicopter performance – useful when you are transitioning, as you can try for a while with the helicopter flying in a more aggressive style and then flick it back to your usual more balanced position to recompose yourself; then have another go with it flying more agile.

The factory settings on the mix switch can be readily changed through the touch screen menus and the stability/agility of the helicopter is always a product of what is set in the transmitter and the settings made on the receiver/gyro itself. Thus if you increase the sensitivity on the gyro through the unit on the RC helicopter, Pos 0 will represent 75% of that, with Pos 1. 70% of that and Pos 2. 40%.

The beauty of a transmitter like this is that the permutations are endless and you can fine tune each helicopter to your individual preferences and flying style. The settings for each helicopter are then stored under a separate profile selectable from the touch screen menus.

It is a great transmitter for a great RC helicopter.

Have fun!

Wednesday, 23 November 2011

And Now For Something Completely Different - Well Not Quite!

Well at the weekend I took a break from my world of RC helicopters and tried something else rather exciting. A friend and I went over to Bruntingthorpe race track and aerodrome, near Lutterworth in Leicestershire, to have a go at driving some supercars with Trackdays/6th Gear. There was a bit of a raw wind blowing and by the time we were called over for our drives, having had a preview lap being driven round in a Range Rover Sport, we didn't know if we were shaking with excitement or cold!

Lamborgini Gallardo

I had chosen the Lamborghini Gallardo, which was sensationally quick and gripped the track like you wouldn't believe. The only problem I found with this car was that I had trouble finding the brake pedal which meant that I was looking to come off the power early to locate it. The difficulty is that not only is the space between the pedals small, not a problem for me as my feet aren't large, but there was something that stuck out above the brake pedal and I kept catching my foot on that stopping me hitting the brake.

My friend however had no such problem in her chosen supercar, the Ferrari F430, in classic Ferrari red and managed to outscore me. Next time Fi!!!
Ferrari F430
For thrill seekers who love cars it's a must do. How does it compare with flying an RC helicopter for fun? Different! They are both unbelievable in their own ways...but I tell you what, you can get alot of flying time for the price of a supercar drive.

It sure was a brilliant day and the company made it all the more so...thanks again Fi.

What the day did do was set me could hear the cogs whirring...the companies that do experiences like this for thrill seekers do cars, helicopters, planes, tanks etc etc etc. Now maybe someone could come up with something similar so people can experience the amazing fun of flying an RC helicopter. Maybe start them off with 1/2 hour instruction on a flight simulator before a try at a co-axial helicopter and then the indomitable little Blade mSR before letting them lose on having a go on a big bird...something like a nitro (the noise just adds to the adrenaline rush) helicopter of at least a 600 size - impressive in the air and stable. This would have to be harnessed to a buddy box so that an experienced pilot could get them up and down safely. Top it all off with a demo from a crack 3D pilot, like this...

...and I think it would be a real thrill for people and a brilliant taster of a rapidly growing hobby.

So, if someone out there takes my idea up and makes a fortune from it...please send me a slice!!!

For now, HAVE FUN!!!

These guys certainly did:

                                                       The Other Way To Use A Buddy Box!!!

Friday, 18 November 2011

Further Adventures With The mCPx

Well yesterday was a perfect day for flying - mild, bright cloudless skies and little or no breeze. Just as Murphy would predict though I had a day of appointments and other business to attend to resulting in no opportunity to get out flying. That just made me all the more determined to go out today and would you believe it the weather today was back to cloudy and breezy, with some quite strong gusts easily exceeding 20mph. This is well on the limit for the mCPx and more windy than conditions I have flown it in before.

Seeing as I had to go out anyway to the local post office I thought I would take it with me and go to the flying field - or more precisely the village green (now how quintessentially British is that, a term you wouldn't see used elsewhere in the world I dare say!). It is lined by roads on two sides and garden hedges and trees on the other two, is large enough to have a small children's football (soccer!) pitch in the middle and is covered in short to medium cut grass turf - just ideal for mCPx flying.

The Village Green

I started off flying quite gently, just gauging the wind and the effect it was having on the little mCPx. For such a tiny RC helicopter it handles the wind extraordinarily well. Then something strange happened. During this reserved flying the helicopter just started spinning like it was under full rudder and dropped to the ground. My immediate thoughts were that the main gear had dropped (as it will commonly do on impact but has never done before mid-flight), losing all transmission to the main blades and allowing the body to just spin. Actually it isn't even the likely effect of such an event and on inspection the main gear was still in place and there was no play at all in the main shaft. Further reflection makes me wonder if there was a momentary loss of power to the tail motor - with no counter-acting force to the revolution of the main blades the helicopter would spin as it did.

Having checked the helicopter over thoroughly and found nothing a miss I spooled it up again and as everything was fine with it I gave it another flight. It was performing quite happily so I decided next flight I would try putting it into Flight Mode 1 (which allows negative pitch for inverted flying). At this time the wind was picking up and clearly too strong now to try at getting the mCPx inverted.

The next flight I stayed in Normal Flight Mode and I was pleased with how well this sub-micro class radio controlled helicopter was handling the increasing wind. Then a particularly strong gust lifted it skywards and carried it towards some trees bordering a garden. In danger of going either into a tree or losing it over a hedge into a neighbouring garden I swung it around and pushed the nose down slightly to get it moving forwards and away from the obstacles. However, it was still drifting away from me and the extra lift from facing into the wind just increased its altitude further. My response was to push forward still further on the elevator to try and get some forward momentum into the wind but ended up with it just plummeting from the sky and into the fortunately soft grass.

The damage report:
  • Mud and grass on one of the main rotor blades
  • One missing push rod link from the swash plate to the blade grip (no surprise there then, these come off quite readily and you have to be prepared to lose a fair few)
  • Slight gnarling of a few teeth on the main gear but no tooth had lost its complete width so it is still usable until a replacement arrives (obviously as the main gear was thrown down on impact the motor pinion flat spotted just a part of a few teeth rather than going through the whole tooth had the main gear not thrown) - a quick test has subsequently shown that it still runs smoothly.

 The Derlin Main Gear by Xtreme - harder wearing than the standard main gear.

  Well, with no spare push rod links with me it was time to head home - reflecting on what had happened and what different responses might have been needed.

Time to get some more links ordered (I am down to my last two now) and wait for a slightly less windy day to try again.

In the meantime, here is how it should be done: