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Posted by navigator2011 | Feb 26, 2013 @ 02:55 PM | 26,854 Views
Blade balancing certainly is a fundamental part of flying helicopters, but it can also be one of the more frustrating and tedious tasks involved in setting up a helicopter. A typical instrument for balancing blades is a simple seesaw type of device, where the helicopter blades are fastened onto opposite ends of the seesaw and then the angle of the seesaw and blades can be directly observed. The seesaw portion of the blade balancer typically rides on bearings so as to minimize errors due to friction. Blades that are very well balanced should sit nearly horizontal, perpendicular to the direction of gravity. When the angle of the blades and seesaw is not horizontal, the blades are out of balance and will cause vibrations during flight. Typically, an appropriately sized piece of clear tape is applied to the center of gravity of the lighter blade to bring the two blades into balance.

Ideally, the base of the blade balancer should be placed on a flat, horizontal surface so that the angle of the blades and seesaw can be compared to that of the surface. One difficulty that I continually encounter is that there is not even one truly horizontal surface in my home. This causes blades to appear unbalanced even when they are actually balanced. Of course, this can be overcome by taking careful note of the angle of the surface, but it is not the easiest approach. Another difficulty is that it can be difficult to discern small angles. For example, a difference in 0.05g on 450-...Continue Reading
Posted by navigator2011 | Jan 30, 2013 @ 01:19 PM | 20,559 Views
What had originally started out as a simple main bearing replacement turned into a full-blown rebuild of my 450 Pro. I can never resist the argument that while the heli is already apart, I might as well do things right, not over. As a consequence, this formerly clone 450 Pro is now almost entirely an Align Trex--I think the carbon fiber frame, main gear, and skids are the only remaining clone parts. Oh, yeah, the motor is not Align, either. I used a Turbo Ace 804 Brushless Supremo Motor, which seems to have plenty of power for this helicopter.

All along my intention has been to turn this heli into a proper Align Trex 450 Pro, but there are a few noteworthy areas where I have deviated away from Align. One thing I decided to do was install turnbuckles for the servo links. Turnbuckles are offered at quite a few places online, but it seemed that everyone is constantly out of stock. I did finally manage to find Tarot TL45116-02 Servo Linkage Rods 1.5mm x 19mm. These turnbuckles make leveling the swash incredibly easy without destroying the links by popping them on and off the swash balls repeatedly. Every kit should include a set of turnbuckles!

Another important factor concerns the Align DFC rotor head. When I first began assembling the DFC head, I was a bit shocked to find that the DFC head dampers are so rigid, as though they were just solid plastic. On my other, conventional Align rotor head, the dampers are rubber. The rubber dampers have worked out very...Continue Reading
Posted by navigator2011 | Dec 03, 2012 @ 03:14 PM | 23,436 Views
After having put the Hybrid 450 Pro into the air without any problems, and having sold all of my V400D02-related equipment, it is time to return my attention to my other 450 Pro. In the course of building the Hybrid 450 Pro, I found that the clone rotor head was irreparably warped, and so I substituted the Align rotor head from my regular 450 Pro. The Hybrid 450 Pro is flying very smoothly with the Align rotor head, but this left my regular 450 Pro without a decent rotor head. This seemed like a good time to spring for an Align Trex 450 DFC Main Rotor Head Upgrade Set, Part Number AGNH45162.

I suppose I didn't research this purchase quite well enough because only after receiving the DFC rotor head did I start encountering postings about the DFC grip links snapping. It appears that the tiny threaded grip links do not extend deep enough into the plastic ball links to provide adequate support, possibly during flight and certainly not during a crash. While there are many people flying just fine with the DFC links, there seems to be a growing number of people who've crashed and cannot determine whether the links simply snapped on impact or actually broke first and caused the crash. In either case, the threaded links that come with the 450 DFC kit look very small and fragile by any standard. There is no way I will put a heli into the air when I have foreknowledge of a weak link that I fear could cause a crash, so my 450 Pro has been grounded for a while as I work to...Continue Reading
Posted by navigator2011 | Nov 16, 2012 @ 01:34 PM | 17,790 Views
After having stripped off all of the dual brushless electronics from the V400D02 for installation on the Hybrid 450 Pro, I discovered that I had enough leftover spare parts to completely rebuild the V400D02 all over again. Well, I had everything except the Rx2614V receiver, anyways. The V400D02 now has a COCO Superframe, Hitec HS-5055mg servos, a brushless Esky main motor, an RTF-Heli style signal converter, and the stock brushed tail motor. All of these parts are used, but are still working just fine. Although a brushless tail motor is preferred, my original reason for changing to the brushless tail was reliability, not performance. The stock tail always handled well enough for this heli, but the stock motors are frequently reported to quit working quite suddenly. At any rate, the objective of this build was to use up a lot of the spare parts I had on hand, and I didn't want to spend any extra money on this heli.

It is no secret that installing the brushless system on the V400D02 can require a lot of wiring. Another objective of this build was to minimize the amount of wiring needed, especially inside of the lower frame area, which houses the battery. Minimal wiring makes the heli lighter, looks better, and allows for the use of bigger batteries. The lower frame area is now largely void of wiring--at least as compared to previous builds. The wires from the battery to the stock ESC and the connectors to the brushless ESC are soldered together into one assembly. The brushless ESC still can be unplugged, which simplifies putting the ESC into programming mode and setting the throttle range. Additionally, rather than using zip-ties to consolidate excess wiring, I have used heat shrink to organize all of the wires that plug into the receiver. With the heli set up this way, I should be able to attach an Rx2614V, plug in all the wires, set the throttle range, and then go fly with minimal fussing around.
Posted by navigator2011 | Oct 29, 2012 @ 01:10 PM | 21,300 Views
If you visit the Walkera V400D02 thread, you will find that it's no secret that the V400D02 frame is very lightweight and flimsy. Many RCG members have reported that the upper portion of the frame just below the main motor is prone to cracking; and once that happens, strange wobbles begin to present during spooling. The lower portion of the frame is easy to bend, as well, thereby changing the shape of the battery cage and giving the heli a noticeable lean when sitting on flat ground. Moreover, the plastic boom mount is easy to snap in a moderate to hard landing. Aftermarket parts must be purchased in order to reinforce the boom.

I have never been a fan of the V400D02 frame. One problem I found is that the battery must be loaded into the frame, thus limiting the size and dimensions of the batteries that may be used. Another problem I encountered is that it is difficult to secure the battery inside the frame. Walkera supplies stiff rubber bands with the V400D02, but I didn't like forcing rubber bands onto the frame every time I loaded a battery. Velcro seemed to work pretty well, but then I needed a spatula to insert and remove the battery.

Another annoying aspect of the V400D02 frame is that it limits the types of cyclic servos that may be used. Small brackets are utilized to secure the stock servos to the frame. I had to cut and hack the servo cases to fit them into the brackets, remove a portion of the V400D02 frame for clearance, and drill new holes in the...Continue Reading
Posted by navigator2011 | Oct 25, 2012 @ 11:04 AM | 18,739 Views
When the stock brushed main motor and brushed tail motor in the Walkera V400D02 are replaced with superior brushless main and tail motors, there arises a few other issues that must be worked out. One issue that was discussed previously is the need for creating a power check bridge for the Rx2614V. The power check bridge enables the Rx2614V to power the brushless motors in the absence of the stock brushed ESC. Another issue is setting, or programming, the throttle range in the new, brushless ESC.

A typical approach to programming the throttle range in the brushless ESC is to turn on the transmitter, raise the throttle stick to its highest position (e.g., 100% throttle), connect the battery to the brushless ESC, wait for the brushless ESC to issue 'two beeps,' and then immediately drop the throttle stick to its lowest position, 0% throttle. The brushless ESC then finishes initializing and all is good. Although this sounds simple enough, it doesn't appear simple when the V400D02 is involved. The reason is because Walkera transmitters and receivers often take up to 10 seconds to bind, whereas most brushless ESCs want to initialize immediately. By the time the Walkera system begins sending a high-stick signal, the brushless ESC has already stopped listening.

Of course, there are ways around this problem, depending on the type of receiver you are using. For instance, with the Rx2702V in the V450D01, you can speed up the binding process considerably by setting a fixed...Continue Reading
Posted by navigator2011 | Oct 24, 2012 @ 01:01 PM | 16,167 Views
It is no secret that the stock, brushed main motor and tail motor that come installed on the Walkera V400D02 are woefully underpowered and a chronic source of grief for virtually everyone who has become involved with this helicopter. The only component that ranks worse than the motors is the stock servos--many are stripped right out of the box. Changing the servos to metal gear servos ranks very high on the list of needed improvements to the V400D02. Changing the servos is a topic for another day, however. Here, the topic is generally related to replacing the stock brushed motors on the V400D02 with brushless main and tail motors.

Many members have gone to the trouble of purchasing and installing all of the parts needed to convert the V400D02 to a dual brushless heli, only to find that when the battery is connected, the heli just sits motionless, repeatedly beeping. The reason this happens is because the Rx2614V receiver needs to 'see' some voltage from the ESC before the receiver will power the motors. When you look at the Rx2614V, you will see a Power Check port which receives a plug from the stock ESC. Although the Rx2614V is powered by the ESC through a Main port, the receiver apparently also needs to detect power to the Power Check port. When we convert to a dual brushless system, of course we remove the stock ESC, and with it goes the plug to the Power Check port. Even though the Rx2614V then receives power from the brushless ESC through the Main port, the...Continue Reading
Posted by navigator2011 | Oct 23, 2012 @ 02:25 PM | 20,175 Views
As most RCG members will tell you, a universal rule in this hobby is that RTF helis rarely are ready to fly safely out of the box--and the Walkera V400D02 is no exception to this rule. A misadjusted micro heli can be annoying and tricky to repair, but a maladjusted V400D02 is very dangerous and quite a bit more costly, too. You will be best served to make it a personal requirement to go through any new heli and perform a mechanical set up before even attempting to spool up. So how do we mechanically set up a V400D02?

The picture below shows a V400D02 that is properly set up. When the throttle stick is positioned at 50%, each of the servo arms is at a 90-degree angle to the servo casing, the swash plate is level, and the swash plate is positioned in the middle of its total path of travel along the main shaft. Additionally, the two grip links should be the same length, and adjusted so that both main rotor blades have zero blade pitch. Many beginners are uncertain how to make all of these adjustments. The following steps are intended to provide a formula for setting up the V400D02.

The first thing to do is unplug the main motor and the tail motor--this is the best way to prevent an accidental spool up and injury. With the motors disconnected, put the throttle stick to 50% in stunt mode (ST-1), and switch the receiver from WK mode to ADJ mode to turn off the 3-axis gyro. This will put the servos into their centered positions without the 3-axis gyro interfering....Continue Reading