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MRC’s XRB Helicopter Review


At the January 2003 AMA Convention in Pasadena, CA. I first saw an XRB Mini Lama electric helicopter and I thought it flew great and was a very cool item. In my review of the convention I expressed my interest in getting the item but that: “I resisted…for now!” That model flew at the end of a 12 foot tether and for some reason that tether kept me from buying one. In October 2004 they came out with the new XRB SR (Sky Robo) Lama, flying without tether using a four channel FM radio system and a two cell Lithium battery for power. They even improved the looks of the model by making its basic color silver with red highlights. My resistance was now gone and I had to have one.



Kit Contents

The quality of this product was apparent to me well before I had finished unpacking the kit. I saved the box — I can easily store my XRB in its original packaging when not flying or displaying it. The copter took up the front 2/3s of the box and was packaged in plastic that allowed me to see what I was getting through the front of the box, while keeping the copter from shifting or being damaged in normal transport. The back 1/3 of the box securely held the transmitter and all other parts in individual bags inside two cardboard boxes that were secured in the cardboard “tray” in the back packaging. The box was/is an excellent way to store and protect everything when not in use.

My kit included a two-cell Lithium battery all ready resting in the battery tray under the helicopter. In a small box to the right of the transmitter were six sets of replacement blades with three pairs for the top of the mast and three pairs for the bottom of the mast. Also in that box was the hub for training gear for a beginner to use. In the second and larger box that was stored to the left of the transmitter were all the other parts. This included the Lithium battery charger, the safety (beginner) skid parts, the skid braces, the blade balancer, two small screw drivers and an Allen wrench, light weight stabilizer weights, a card to fill out and an excellent instruction manual.

The instruction manual was excellent and I highly recommend that every pilot read it before flying the XRB. It was a very quick read with large text and many pictures/drawings. Pages 19-23 described how to balance and adjust the helicopter for blade tracking, movement in any direction and adjusting the yaw. The instructions also covered fine tuning and setting the XRB up for an expert pilot. They clearly showed what transmitter control caused what movement with the helicopter and gave recommendations for starting flight. The assembly and reading of the manual took little time and was well worth the effort.

I did need to buy 8 AA size batteries and installed them in the transmitter. Otherwise everything I needed came in the box.


For the inexperienced helicopter pilot they supplied a simple to assemble training skid that they called the Safety Skid. It snapped together as shown on page ten of the instructions. It’s to help keep the beginner from tipping over on landings and take-offs.

The Lipoly battery slid into a battery holder under the copter and plugged into the copter only for flying. They recommended that it remain unplugged when not flying to avoid having the voltage drawn down and possibly ruining the battery. The three wire plug was unusual to this reviewer and complicated trying to use another brand of Lipoly as a backup battery.

The XRB came with the standard round stabilizers that supply higher stability and slower response. But they also packed a pair of light weight (flatter) stabilizers for use by advanced pilots. These reportedly supply lower stability but quicker response. The switch between the two different pairs of stabilizers appeared simple in the instructions. They also showed how to change the connecting rod on the stabilizer to the other side of the stabilizer to get quicker response. All flights for this review were with the standard stabilizer.

To store my assembled XRB in the original box, after I installed the skid braces, I had to make some cuts in the protective plastic with my Exacto knife to fit the copter with the skid braces back into the protective plastic. The two pictures below show the plastic with parts removed to fit the skid braces. The second picture, showing the black back piece, best shows where I cut out plastic.

Side notes:

As mentioned in the introduction, I first saw the tethered version of the XRB at the AMA Convention in 2003. Below is a picture I took of it being flown in demonstration and a picture I saw on the Internet of the RED tethered XRB. in talking about it with a friend at the time, he didn’t like the look of the counter-rotating blades and thought it didn’t look real because of them. I told him that some of the first attempts at helicopter type vehicles involved counter-rotating props and that the Soviets even had an attack helicopter powered by them. The photo below of the KA50 Black Shark won me a free lunch. I have included a couple of pictures of it below.

If you would like an XRB Lama to look even more scale then the one I reviewed, they do sell an interior for the copter as an accessory. While I loved the scale looks of the Lama I understand that at the Tokyo Toy Fair last year they unveiled an Airwolf body that may become available as an accessory for the XRB in the future. The second picture below is from the Tokyo Toy Fair. The third picture is one that Tikaboo posted in RCGroups as I was reviewing the XRB. Unfortunately, I know nothing more about the Airwolf versions of the XRB other than the pictures are cool.

Improvements over the Tethered XRB

Besides the most obvious changes of RC vs. tethered and silver vs. red, I noted several other changes in the new XRB from the original. The first was the addition of the little jet engine on the top back of the copter. While purely cosmetic I found it a very eye appealing addition.

A more important change was the taller mast which gave more separation for the counter-rotating blades. This change was not important for most slow beginner style flights but was significant for the pilot that wanted to do faster more aerobatic maneuvers. In the faster maneuvers the blades of the original XRB were known to sometimes strike one another as the foam blades flexed during the rapid change in direction. With the taller mast that should be far less likely to happen. This is a design improvement that affects performance in a positive way.


I took my XRB to my church for the first flight out of an abundance of caution. This gave me a large and mostly empty fellowship hall in which to fly and got me away from possibly breaking Christmas decorations that are all over our family room, and I do mean all over the room. At the hall I did a final ground check of the XRB and listened to the smoothness of the servos as I slowly moved the transmitter sticks with the throttle off. I also did a range check with the transmitter antenna down and it failed my normal test with the antenna all the way down. However, I had plenty of range with the antenna at half mast. (They did a nice job wrapping the receiver antenna in the cockpit area of the copter.) With all systems go it was time to fly.

The power up procedure:

  • Always turn on the transmitter first and make sure the throttle stick is in the off position.
  • Remove the front compartment from the copter.
  • Plug the Lipoly battery into the fixed socket in the front right of the XRB.
  • Reattach the front bubble compartment.

I got my friend Bob Ramirez to come out of the church kitchen to videotape my first flight. I set the XRB on the ground facing away from me and I positioned myself behind it by about six feet. Its right was my right and so on. I powered up the motor, lifted off, and it wanted to fly backwards.

Type Name
This version of the first short flight is for dial up users.
0.1 MB

It was tail heavy (my fault) so I shut it down and landed. Per the pictures below, the wire from the battery can hit the bottom of the canopy. I had felt that resistance and thought the battery was all the way forward. When the XRB initially wanted to go backwards, I immediately thought of the battery and landed and I was right. I bent the wires coming out of the battery slightly, and it installed properly immediately. I put the canopy in place and was ready for attempt # 2.

Type Name
“Success” for dial-up users.
0.4 MB

The XRB hovered on the second flight, hands off, with only one or two clicks on the rudder trim tab during the flight. After the short videotaped portion of the flight I was able to get in another ten minutes of flying and was moving the XRB where I wanted with very good control. I even tried a few emergency let goes of the right stick when the XRB was in forward and slide flight and it stopped its progression and went into a hover within a few feet. This is a novice friendly flier. I went and asked my pastor, Reverend Robert Mitchell, if he could take a few still pictures of the XRB in the air and the stills below were some of the ones he took. After about 16 minutes of flight time I lost the ability to climb with the copter and during the next minute or so I flew just above the ground in a small box pattern before the low voltage forced me to land. No damage, no crashes, and, most amazing for me, I was not the least bit tense. I did intentionally make some slightly fast angled landings during the main portion of my flight time and safety skids helped the XRB land upright.

I went home and recharged the battery. (It takes about one hour and fifteen minutes to completely recharge after a full flight discharge.) I got in a second flight but this time I was by myself. I started on the coffee table and flew up and over the sofa and landed on the informal dining table in the family room. This was a tricky approach because of a low-hanging light fixture but I was successful. I had never tried that with my other copters but you can bet I will in the future…when I am home alone. Taking off from the table I slowly flew through the kitchen and a couple of archways as I went through the dining room and living room and back into the family room. I made a pass over part of the Department 56 “Dickens Village” and I caused a blizzard with the artificial snow and made an emergency landing as I was a caught off guard. Cleaning up that mess was the only downside to my flights. I recharged the battery so the XRB could be flown at my club’s Christmas party that night.

This was easily the most relaxing hands on flying experience I have had with any helicopter. I did get pushed around a Little when I was flying up near the air duct in the church hall when the heater kicked in. That action helped confirm that this is an indoor flyer unless there is no wind at all outside.

At the Modesto Club’s Christmas party I again had trouble getting the bubble compartment on the front of the copter due to the wire from the Lipoly battery. I had Jeff Hunter fly without the front bubble in place. This was Jeff’s first flight with the XRB and it was in a room full of people…but I had assured Jeff the XRB was rock solid. He took off from the table in front of me. I started the video camera about ten seconds into the flight. Jeff is an expert pilot, and he acknowledged that the XRB is very easy to handle as it flies so steady in the original set-up.

Type Name

This version of the flight at the party is for dial up users.
0.4 MB


This review focused on the XRB RC version in its most stable set-up, the way it was sold. With the battery properly forward the XRB was rock solid indoors with no heating or air conditioning on. When they came on I could no longer fly hands off but it remained very easy to control. If someone has some flying experience so that they know the vehicle’s left and right, coming and going then they can probably master this copter with just a little practice. Start with a lot of room and when you feel comfortable you can start flying in a regular room with furniture. I am fairly new to helicopters but I felt completely comfortable after I got the battery properly positioned during the flying on the first battery charge. I even felt comfortable flying it through archways between rooms at my home during the second battery charge. I love how it handles!

The only problem I had of any sort was getting the canopy on over the battery wires where they come into the fuselage. I was successful at the church and at home earlier in the day but I again had trouble at the party. I examined that more closely. A truly minor problem when I think of problems people have with some other micro helicopters! I removed a small piece of plastic about 1/16th inch wide about 3/8ths long center bottom of the plastic compartment. now the wire just jits in that slot and i have no problem with it. I look forward to flying it frequently during the next month or so in the current stable set-up. After that I will change over to the more responsive settings with lighter stabilizer weights with a flatter shape and move the rod to the other side for more movement. If that makes a substantial difference in performance I will either report that here or do a mini review update with a video. For now, if you are interested in learning how to fly a helicopter, this is an excellent choice.

Radio Control Plane & Helicopter Simulator

Many people do not believe in simulators. Why? Because they don’t think it helps them in flying a real model. After all… what’s more realistic than to fly the real thing? Well, I will have to tell you that simulators these days mimic the real thing pretty well. The costlier simulators all have photo-realistic backdrops which make the simulator experience even more real. Coupled with superb model flight characteristics, you will feel as though you’re there at the field but from the comfort of your home.
Simulators have been introduced to help beginners learn the basics of flight, control inputs, orientations, What If’s & scenario practicing, e.g. takeoffs, landings, 3D Flight, Acrobatic, Etc. It also allows the more advanced user to practice advance maneuvers which will be too risky to try on real models.
A simulator if used well will help a user learn fast. The cost and money factor of crashes which limits a student’s learning capability is eradicated with simulators. Students tend to be more daring since a crash costs nothing more than a simple push of the reset button. Heck… the simulators nowadays actually do the resetting for you so you don?t even have to push any reset buttons!
Though the initial outlay for a proper simulator may be quite substantial, let me assure you that you will make up for the cost the first time you use the simulator. A crash or two on the simulator already makes up for the cost of a real model, not to mention the amount of time saved from having to order parts and re-build or build another model.
There are many different RC simulators in the market. Some are free and some are not. If you just want to learn the basics then a free simulator would be good enough to help you gain orientation skills and the necessary reflexes to fly an r/c model. After all, flying is all about trained reflexes under different scenarios and orientations. Normally the more expensive simulators will have better flight physics thus more accurately mimicking real life scenarios.
Simulator Most simulators will require you to use your own R/C Controller which plugs into your computer either via a serial/parallel or USB cable (dongles). Freeware Simulators will allow you to connect home-made serial/parallel/USB connectors from your controller’s trainer port to your computer. Paid simulators will come with their own dongles which basically is the copy protection built into the software to prevent piracy.
You can connect a controller as simple as a joystick to the PC to start trying out the simulator but the best way to train is to use a proper 4 Channel Controller. Better still, if you want to use all the features of some of the simulators like Flight Modes (for Helicopters) then a 6 Channel or higher controller should be used. Most controllers like FUTABA, JR PROPO, & etc can be connected to the simulators which normally come with their own connectors and adaptors to support most types of radios. Some simulators even have their own “dummy” controllers which will allow you to fly the simulator but cannot be used to control a real R/C model since they do not that transmission capabilities. They are basically ?joysticks? in the shape of a controller.
Personally, I have tried Real Flight G2 and Aerofly Professional Deluxe (AFPD). I would recommend AFPD because of the nice true to real life flight characteristics of helicopter models plus the photo sceneries just make the flying experience so much more enjoyable and realistic.

Aerofly Pro Sim1Aerofly Pro Sim2








Here’s a list of some of today’s more popular simulators, not necessarily in order of preference or performance.


Aerofly Pro Sim3


End-to-End Battery Soldering Technique

What you need:  

There’s a few key concepts to remember when doing end to end soldering. Surfaces must be clean and the iron must be hot/massive enough to transfer sufficient heat in only a few seconds to minimize damage to the cells. Wear safety goggles – the solder will splatter! Here’s what is needed to do the job:

Soldering iron: Although a larger 60-80 watt iron is often recommended, I find that I can get along fine with the Weller 40W WLC100 soldering station. This iron is great for other types of soldering that you would likely be doing and comes with the screwdriver tip in the photo below . The only drawback is that after doing several joints it’s a good idea do give the hammer head tip some time to refill its “reservoir” of heat.

  • Scotch-brite scrubbing pad
  • Kestler 60/40 rosin core electronic solder
  • Corrosion free flux (even though it apparently is a bit corrosive) is useful in tiny amounts
  • Sponge (wet) for cleaning solder tip. One is included with the WLC100
  • Masking tape – 1-1/4″ wide if to be used as insulation between cells
  • Soldering jig – one can be made from wood, but I went with a magnetic jig available through Hobby Lobby or New Creations
  • Pre-made insulators or a brass tube of the correct diameter sharpened on one end to cut out holes in the masking tape to match the diameter of the cell buttons
  • Heat shrink to fit the assembled pack , 2-5/8″
  • Heat shrink to fit assembled stick, if used, 1-7/16″
  • Hot melt glue
  • 1 pair of end caps, if used
  • Small bench vise
  • “Extra hands” stand to hold wires and connectors while soldering them. The wooden one in the top left corner is good for connectors because it doesn’t pull off the heat.
  • Large straight blade screwdriver to remove heat from cells after soldering.
  • 13 gauge silicone wire
  • battery connection braid
  • battery connector ( I use Astro Zero-Loss)
  • heat gun

Pack construction:

  1. Prepare the insulation
    • Make button insulators for the positive end (if pre-made insulators are not used)
      • Lay 4 or so strips of 1-1/4″ masking tape onto a hard cutting surface in a stack so that 4 insulators are made with each cut.
      • Cut the strip into squares with a steel rule and a knife.
      • Use a sharpened brass tube of the correct diameter to make holes to fit tight against edge of + button and drill holes in the centre of the tape squares. Make enough for more than double the number of the cells to be soldered.
    • Make 1/8″ to 3/16″ wide strips of masking tape by repeatedly scoring the roll of tape so that 4 to 6 tracks are made on the tape roll for pulling off these narrow strips. I have used a balsa stripper for this.
  2. Prepare the cells
    • Strip off both layers of heat shrink (RC2400) to give bare cells.
    • Take a small piece of Scotch-brite pad and scour the cell’s button and a similar sized area on the other end.
  3. Apply cell insulation
    • At some point get the soldering iron heating up during this stage. In fact these first steps can be intertwined with other steps so that the soldering iron can recover its heat.
    • Install the “+” button insulators. Either:
      • install pre-made insulators (usually plastic) and hold in place with a couple of small pieces of tape to be removed later.
      • apply two of the masking tape insulators made earlier – the second one being rotated 45 degrees so that there is an 8-point star wrapped around to the side of the cell. Roll on hard surface to flatten against cell.
    • Apply two wraps of 1/8″ tape on each end of each cell. In the case of the homemade button insulators above, use only one wrap over them. This insures that the tape thickness is the same on each end of the cell to keep the cells aligned exactly inline during soldering. The purpose of these wraps of tape is to provide non-meltable insulation between the cell sticks in the assembled pack in case of severe overheating – during which both the heat shrink and hot melt glue could start melting away. Remember that you don’t need these with the LOGO 10 packs and their plywood keel.
  4. Tin the cells
    • Arrange all the cells together with the same end up. I do the “+” end first.
    • (Optional) Use a toothpick to apply a little smear of flux.
    • Get the large screwdriver ready to touch to the heated area of the cell immediately after the soldering iron is removed.
    • Clean the soldering tip on the wet sponge and apply a little fresh solder to it.
    • Touch the tip to the cell end for only a couple of seconds (or until the flux is observed to melt) and touch the end of the solder to the heated area. Feed in just enough solder to give a very thin layer of solder. Swirl the solder tip around the edges of the tinned area a bit just as the tip is removed. This whole step should only take a few seconds.
    • As soon as solder is finished being fed, drop it and grab the screwdriver so that at the very instant that heat is removed one can…….
    • Press the flat screwdriver blade on the heated area so as to pull off as much heat as possible from the cell.
    • Repeat this with all the cells, stopping to allow the tip to heat up when poor soldering is noticed.
    • Flip the collection of cells over and tin the other end. Note that in the case of RC2400 cells there is a purple substance that reminds me of grape jelly in a recess at the centre of the cell. It can be ignored as it melts and flows off to the side.
  5. Solder the cell sticks together (technique particular to magnetic jig)
    • Turn off the soldering iron and allow it to cool down enough to change to the hammerhead tip and of course turn it on and give it ample time to heat up again. Hint: Visit the EZone for awhile during this operation, hehe.
    • Set up the soldering jig. In the case of the nice magnetic jig, clamp it in the vise. I add an extra measure of insulation to this jig by:
      • wrapping the piece at the end of the jig which clamps in the vise with electrical tape for those times when you must solder the sticks with the +end down (repairs).
      • putting two strips of clear tape on metal rails where the bare cell sides contact it.
    • Put the first cell on the jig with the “+” end up and put the next one just above it – slightly further apart than the height of the hammerhead tip.
    • Clean both ends of the hammer head on the wet sponge and lightly tin them.
    • Place the soldering tip between the cells in proper position for soldering in the next step.
    • Drop the end of the hammer head firmly and squarely onto the “+” button while simultaneously bearing/sliding down with the top cell onto the other end of the hammer head. I sometimes wiggle the handle of the soldering iron to get a feel for square contact between the two cells. This step should take a few seconds at the most
    • QUICKLY: Lift/slide the top cell enough to allow easy extraction of the hammer head and then smartly slide the top cell down to join the two areas of pooled solder. If you get more than a little solder splashing out then you are using too much solder. If you are not following my recommendation to remove the shrink-wrap and are soldering up a flashy pack with the labels lined up nicely (I do this sometimes), then exaggerate a bit of a lift as you are pulling out the tip to clear the edge of the shrink-wrap, so as to not melt it.
    • Lift the stick /stack high enough to place the next “victim” at the bottom and repeat. Note that since the completed portion of the battery stick is at the top, the length of the battery stick can extend well past the end of the jig.
    • You might as well pace yourself here, because after 5 or 6 joints the tip should be allowed to recover its heat for a few minutes. To kill the time, I usually take a razor knife (bonus sparks possibly), thin cardboard, or thin plastic sheet and extract any solder balls by sliding them between the cells.
    • If (when) you get a bad result, give it a deliberate, quick snap to break the joint. If the cell can is lifted a bit, I tap it flat on the bench (confession).
  6. Assemble the pack
    • Turn off the soldering iron, let the tip cool down enough to remove it, install the screwdriver tip, and turn it on again.
    • Install the shrink wrap on the battery sticks, if used.
    • Glue the sticks together (to the keel if a LOGO 10 pack) in proper orientation with a small bead of hot melt glue. I get the two sticks lined up on the bench a little ways apart, run the bead on the top of one stick, roll it so that the glue is now at “3 o’clock” and roll the other stick into contact. All this needs to be done quickly before the glue hardens.
    • Tin and install a piece of braid to connect the sticks at one end or….
    • Install the odd number cell across the end.
      • Tin and install two pieces of braid facing outwards from the pack on each cell at one end of the pack. bend them so that they will meet the ends of the “bridging” cell.
      • Place several strips of masking tape across the end of the pack to insulate this last cell where will rest and hot melt glue it in place. It must not be allowed to short out on the other cells!
      • Solder the braid to the previously tinned cell.
        • Protect the pack with cardboard or cloth and clamp it lightly to the bench.
        • Clean and tin the solder tip.
        • Apply solder while pressing the tip onto the braid while keeping it its proper place.
        • Drop the solder, grab the cooling screwdriver, and press it onto the braid to hold it in place while the solder tip is removed. Let the heat escape to the screwdriver.
        • This whole process should only take a few seconds…… Press your thumb on the heated areas. It should not hurt;)
  7. Install the wiring and connector
    • Cut the silicone wire to the proper length, strip and tin the ends, and solder it to the connector(s).
    • Protect and insulate the pack with cardboard while clamping it lightly in a vise with the unfinished pack end facing up.
    • If end caps are used, be sure to feed the wiring through the end cap.
    • Solder the red and black wires in place on the end of the pack, towards each other and slightly to one side. Make sure that the polarity is correct.
    • Heat the end caps with a heat gun to make them more pliable and reduce the chance of them tearing and then install them on the ends of the pack.
  8. Apply outer layer of heat shrink
    • Leave about 1/4″ overhang if end caps are used and the shrink will form nicely around them.
    • If end caps aren’t used leave more slack and
      • On the lead end, leave about 3/4″ extra and form it around the wires as it shrinks and is bent flat in one direction
      • On the other end leave about an inch extra, and fold the flap back against the pack.
  9. Slow charge the pack at C/10 for 14-16 hours to “equalize” it. At C/10 the batteries can dissipate the heat from overcharging while other cells “catch up” to the same voltage.

Batteries – Different Types & Maintenance

There are many types of batteries available in the market these days for RC use and sometimes even experts get mixed up between the different types and the proper care needed for each specific type of battery. This article will help shed some light to new comers to battery power as well as a reference for the experts to refresh their memories on the characteristics of the different types of batteries and the needed care for each type.

Commonly used Terms

Final charge voltage: the voltage at which the battery’s charge limit (capacity limit) is reached. The charge process switches from a high current to a low maintenance rate (trickle charge) at this point. From this point on further high current charging would cause overheating and eventual terminal damage to the pack.

Final discharge voltage: the voltage at which the battery’s discharge limit is reached. The chemical composition of the batteries determines the level of this voltage. Below this voltage the battery enters the deep discharge zone. Individual cells within the pack may become reverse-polarised in this condition, and this can cause permanent damage.

Memory effect: The real memory effect has been recorded by Nasa, caused by repeated charge / discharge cycles. Nasa has found that full capacity can be regained by overcharging the cells. In modelling applications different effects are responsible for the reduction in cell capacity. The problem can be cured by balancing the cells (see below), and prevented by the measures described in Chapter 4.1.3.

Balancing: a method of regaining full (nominal) capacity by alternately charging and discharging the pack, sometimes several times. This process is especially useful after a long period of non-usage (e.g. after purchase, or after several weeks without flying), and is also used to disperse the memory effect (see below). The effect of balancing is to break down the coarse crystaline structure (low capacity) inside the cell and convert it into a fine crystaline one (high capacity).

C: Coulomb or capacity: Unit of measurement relating to the quantity of charged energy. In conjunction with charge current data this unit is used to determine the recommended / prescribed charge current of a battery of a given capacity. Example: if the charge or discharge current of a 500 mAh battery is 50 mA, we refer to this as a charge or discharge at one tenth C (C/10 or 1/10 C).

A, mA: unit of measurement relating to charge or dis-charge current. 1000 mA = 1 A (A=Ampere, mA=Milliampere)

Ah, mAh: unit of measurement for the capacity of a battery (Amperes x time unit; h = hour). If a pack is charged for one hour at a current of 2 A, it has been fed 2 Ah of energy. It receives the same quantity of charge (2 Ah) if it is charged for 4 hours at 0.5 A, or 15 minutes (=1/4 h) at 8 A.

Useful information about batteries and maintenance

General information Do not charge below 0C, optimum is 10…30C. A cold cell is not capable of accepting as much current as a warm one. For this reason you must expect differences in charge characteristics if you use fully automatic charge current calculation (in Winter the charging properties will be worse than in Summer). The best working temperature for a Ni-MH cell is 40 … 60C. At lower temperatures the cell can not supply higher currents. Caution when using those cells a a receiver battery in a helicopter in the wintertime. The lower the internal resistance of the battery, the higher the charger can increase the charge current for that battery. For a battery charger which sets the current automatically the resistance of the cable is added to the internal resistance. For this reason: use heavy cable (large cross-section), even for receiver batteries, and keep them short. Do not charge via a switch or switch harness! If you wish to measure battery capacity accurately a suitable discharge current is usually 1/10 C.

Reflex charging Charging processes which include a brief discharge pulse definitely have the effect that the battery is several degrees cooler at the end of the process. However, from the point of view of the competition operator this is an undesirable effect, as the cell chemistry can only supply high currents if its temperature is raised to a certain extent. All these effects, whether they actually occur or are simply hear-say, have no practical significance if batteries are correctly handled in the first place. When a battery is full, you can’t fill it any fuller!

Memory effect of Ni-Cd & Ni-MH cells If cells are repeatedly stored partially discharged, or are recharged from a half-discharged state, what is known as the memory effect sets in. The cells note that their full capacity is not required, and react by refusing to make it available. One aspect of this is that the crystalline chemical structure inside the cell changes; the cell’s resistance rises and its voltage collapses under load, with the result that “full capacity” can no longer be exploited at normal discharge currents. Even if reflex charging were to eliminate the memory effect, there is no denying the necessity to store your cells in the discharged state; this applies to Ni-Cd cells and also to Ni-MH cells.
A characteristic fact of these cells is that they self-discharge – and the rate of self-discharge is different for each individual cell in a battery pack! If a fully charged pack is left for a considerable time, it will eventually consist of cells of widely varying states of charge. If at this point you …
a) … give the pack a full charge: the cell with the highest charge will be overcharged, heat up and be ruined, while the cell with the least charge will still not be full after the same period of charging.
b) … discharge the pack: the cell with the least charge will be completely flat first, then reverse polarity and often suffer an internal short-circuit. At the point when this happens, the cell with the most charge is still not yet completely discharged.
This is a reliable method of wrecking your most valuable packs – and rest assured that reflex charging will make absolutely no difference. However, there is one method of avoiding the problem: discharge cells after use, and recharge them just before use!

Nickel-Cadmium-batteries (Ni-Cd)
Nominal voltage level: 1.2 V / cells.
Selecting the fast charge current (manual setting): Charge current = 2 C (never less!) (C=nominal battery capacity)
Maximum continous discharge current: Currents of 10 C to 30 C are possible, depending on cell type.
Long time storage: Empty i.e. discharged to the discharge voltage cut off level (see maintenance), at low temperature (-20C to +10C).

Maintenance: Charging: The automatic current setting circuitry (patent applied for) provides optimum protection to your Ni-Cd batteries during charging. The reduced current towards the end of the charge ensures a completely full pack combined with only a slight temperature rise, as you will easily see in comparison with conventional constant current techniques. Do not use the automatic charge current calculation of the Ni-Cd batteries when charging Ni-MH batteries! Discharging: To prevent your cells from memory effect and to keep the full capacity you have to discharge it after use, even when you store it over night (select Auto-D program to discharge down to 0.85V / cell). If a battery is brand-new or used irregularly it is often only possible to balance it completely by carrying out several discharge – charge cycles. Amongst model car operators it is standard practice to erase any memory effect by completely discharging each cell individually via a resistor (approx. 68 Ohm). This deliberately “unbalances” the pack, but it can cause the automatic charge termination circuitry to switch off the current prematurely during the charge process. For receiver batteries special types such as the Sanyo KR500AAEC / N500AC (lower resistance) are a good choice. Warning: The reduced charge current with 1-6 cells makes the voltage peak in the charge curve very slight, especially with batteries of high nominal capacity. In this situation the charger is sometimes unable to detect the “full” condition due to the ill-defined peak.

Nickel-Metal-Hydride batteries (NiMH)
Voltage level: 1.2 V / cell.
Selecting the fast charge current (no automatic program!): Charge current typical 1 C (never less!) (set a fixed current of, for example, 1.2 A with 1100 mAh batteries, or 3 A with 3 Ah cells). Some modern high-current Ni-MH cells made by particular manufacturers can safely be charged at a higher rate of up to 1.6 C (Panasonic 3000: 3,5 – 4A, GP 3000/3300: 3 A, Saft 3000: 3 A (not if battery is charged inside a transmitter!), Sanyo 3000/3300: 4 – 5A).
Maximum continous discharge current: Currents of 5 C to 15 C are possible, depending on cell type. Long time storage: Empty, i.e. discharged to the discharge voltage cut off level (see maintenance), at low temperature (-20C to +10C).

Maintenance: To protect your Ni-MH batteries from the memory effect and keep the full capacity, discharge the cells after use down to the discharge voltage limit even when you store it over night. Never discharge by car bulbs or the drive motor (premature charge termination!), but use only the Auto-D programm when the battery type Ni-MH is selected. The cut off voltage is 1 volt / cell. This eliminates the danger of deep discharge termination and polarity reversal (over-discharge). It is important that you take the trouble to give Ni-MH cells when storing at +10…30C a charge / discharge cycle around every four weeks, otherwise they become tired, and have to be pampered to restore them to full vigour. This involves going through the tiresome business of many repeated charge / discharge cycles. The automatic current setting circuitry (patent applied for) provides optimum protection to your Ni-MH batteries during charging. Do not use the Ni-Cd automatic current selection for Ni-MH batteries! Warning: Never charge fully charged Ni-MH batteries with the Auto C (or ..CD programs): Over-heating and danger of explosion! The cut off automatic is disabled for about the first 5 minutes of charging – this could lead to a minimum charge time of about 10 minutes! Amongst model car operators it is standard practice to erase any memory effect by discharging each cell individually via a resistor of approx. 10 Ohms in series to a 1 amp silicon diode (1N4001). Warning: At lower cell counts (1-6) and low charge currents (below 2 C) the battery makes only a very low voltage peak when fully charged. Under those conditions the cut off automatic works less reliable then with higher currents and/or higher number of cells. Typical for Sanyo Twicell and RC3000H cells: High maximum load capacity and voltage level. Typical for Panasonic P3000NIMH cells: High maximum charge capacity and voltage level. Typical for GP GT3000 / 3300 cells: Extremely high charge capacity, good voltage level. Can be discharged with medium currents (about 40…45 A).

Lead-acid batteries (Pb) and VRLA (valve regulated lead-acid) batteries
Nominal voltage level: 2.0 V / cell.
Charge voltage level: 2.3 V / cell; 2.42 V / cell for 3 hours.
Min. discharge voltage: 1.7 V / cell (this reduces lifetime).
Number of cells to be selected on the isl 6: Nominal voltage of the battery to be charged divided by the nominal voltage level of lead-acid battery cells = cell count. Example: 12 V-Lead acid battery divided by 2,0 V => 6 cells. Selecting the fast charge current: Charge current = 0.4 C (C = nominal battery capacity) Maximum continous discharge current: Typically 0,2 C, short time load up to 1 C.
Long time storage: Full at low temperature, more precise: at +10C up to 12 month, at +10…20 max. 9 month, at +20…30C max 6 month, at +30…40C 3 month. Charge again after this period.

Maintenance: In contrast to Ni-Cd/Ni-MH batteries, lead-acid batteries must be fully recharged after use in order to maintain full capacity. The nominal capacity can be reduced very quickly by incorrect handling (overloading, repeated 100% discharges, and especially deep-discharges). Please observe the battery manufacturers recommendations. Typical: The characteristics of lead-acid batteries are quite different to those of the Ni-Cd sealed cell packs which are used as the power source in model aircraft, cars and hydro-boats. They can only tolerate relatively low currents relative to their capacity if their full capacity is to be exploited, and/or the voltage is not to collapse too far. Used as single-cell glowplug energiser batteries and power source in some scale boats. Very low self-discharge rate.

Lithium-Manganese-Oxide batteries (LiMnO)
Nominal voltage level: 3.0 V / cell.
Selecting the fast charge current: Up to 0.35 C, dep. on cell type.
Maximum continous discharge current: Up to 1.5 C.

Maintenance: Always store these cells in the charged state.
Typical: These cells are particularly recommended as receiver batteries (2 cells required), although correct charging and storage are very important. However, we do not recommend them as slow-fly flight packs, since they have a limited ability to supply high currents, and their useful life varies greatly according to the discharge current and the extent to which they are discharged. Very good weight : energy ratio. Hint: The most common form of this cell type is the “Tadiran” cell. Tip: Ideally all single cells in a pack should be charged separately; alternatively charge all cells in parallel.

Lithium-Ion batteries (Li-Io & Li-Po)
Nominal voltage LiIo: 3,6 V / cell (SAFT)
Nominal voltage LiIo/LiPo: 3,7 V / cell (SANYO, KOKAM)
Max. charge voltage LiIo isl 6: 4,1 V +-40mV / cell (SAFT) (absolute limit 4.3 V / cell) LiPo isl 6: 4,2 V +-50mV / cell (MoliCel)
Min. discharge voltage LiIo isl 6: 2,5 V / Z.(MoliCel), 2,7V/Z.(SANYO) (absolute limit 2.3 V / cell) LiPo isl 6: 3,0 V / cell (KOKAM)
Number of cells to be selected on the isl 6: Nominal voltage of LiPo-pack nominal cell-voltage = cell count. –> 11,1 V LiPo-pack divided by 3.7 V => select 3 cells! If you would select more, the pack would explode during charging! Example: The Kokam TP8200 3s4p pack consists of 12 cells. 4 of 2050mAh are connected parallel (4p) -> 4 * 2,05 Ah = 8200mAh. 3 of the paralleled cells are connected in series (3s)-> 3*3,7V= 11,1 V.
Selecting the fitting cell type: Select that battery type from the isl 6 menue which characteristics match best with the data sheet of the battery manufacturer. Selecting the fast charge current: Charge current = 1 C (SANYO / KOKAM) or less (0,7 C PANASONIC) (C = nominal battery capacity).
Maximum continous discharge current: Up to 4 C (very new types more), depending on cell type.
Long time storage: Empty, i.e. discharged to the discharge voltage cut off level (see maintenance), at low temperature (-20C bis +10C).
Maintenance: Discharge with 1 C down to above listed discharge voltages. Always store these cells in the discharged state, if stored fully charged, the result can be a permanent reduction in capacity. When stored at +40C or more charge additional every two months. Typical: They are very popular as power supplies for sail winches (2 cells). Their limited ability to supply high currents means that they are only suitable as flight packs with more than 20 minutes flight time (slow flyers, Piccolo, Hornet, Logo10).

Very good energy : weight ratio. Hint: Many manufacturers direct how many cells are allowed to use in series and/or parallel use. The exact technical term of a Li-Po cell is Lithium-Ion-Polymer battery, the “true” Lithium-Polymer cells work only with higher temperatures of more than 60C.

Setting up an RC Helicopter

Setting Up a Helicopter

Raptor 30 HeliFirst thing after you bring your newly purchased Helicopter home, regardless whether it’s new or second hand, is to check that the helicopter is properly set up. Even an experienced helicopter pilot will not be able to fly an improperly set up helicopter. He might not crash it if he is lucky, but he will definitely have a hell of a time trying to fly it right.
A properly set up helicopter will fly the way you want it to. You will not have to fight the controls just to get the helicopter to a position you want it at. Flying improperly set up helicopters is both a risk to yourself and others so please make sure you do it correctly.
The things that are most important to look out for are as follows.
Make sure all parts are secure – You wouldn’t want a screw to work loose during flight. A helicopter needs all its parts to be working in harmony for a successful flight. Any parts which work loose during flight will most definitely be the end of your helicopter. If you’re lucky it will meet terra firma. If you’re not, it will meet someone before crashing. So make sure all parts are secured and put on some lock-tite (threadlock) for all metal to metal screws. Do not put threadlock on metal screws that will contact plastic.
Make sure your blades are properly balanced – There are many things to balance for a helicopter. Firstly are the main blades, you have to make sure that the rotor blades are properly balanced laterally and horizontally. This will ensure that no vibrations creep in when your rotor spins. When you are done with your main blades, make sure your tail blades are balanced the same way. As soon as you see any vibrations on your helicopter, land it and make sure you fix the problem. Vibrations are the source of many mechanical failures. Parts will work loose during flight and wear and tear will be exaggerated. A well balanced vibration free helicopter is a pleasure to fly and it will appear to run smoothly at all times.
Make sure your Helicopter is properly balanced – Do not fly with a nose or tail heavy helicopter. Apart from loosing unnecessary power in maintaining proper balance during flight, you will once again increase unnecessary wear and tear on the swash plate. To balance a helicopter, make sure the helicopter balances at the main rotor shaft. Pick up the helicopter by the rotor head and make sure the helicopter and tail boom is parallel to a horizontal reference. Once that is achieved, your helicopter is properly balanced. In achieving perfect balance, try not to add any unnecessary weight to the helicopter if possible. A heavier craft although more stable will use up unnecessary power. Try to balance the helicopter by re-arranging the positions of your onboard equipment, which may be the servos, battery packs or even gyro.
Make sure no bindings occur – Very important in the functioning of the helicopter is to ensure that no moving parts bind. Make sure the gears are not meshing too tightly since they draw power and increase wear and tear. Other areas of binding might occur on your swash plates. If the swash plates seem to be binding, just reduce the throw of the servos enough to a point where full stick movement will not cause the cyclic swash plate movements to bind.
Ensure servos and equipment are properly installed – When installing servos, make sure that they are properly secured to the craft with no free play or movement. Also make sure that the servo travel direction is properly corresponding to your intended stick movement. If they are not, reverse the servo direction either mechanically if possible or though the controller. As a general rule, ensure linkages from the servo horns are at 90 degrees position at center stick. This ensures linear movement on both sides of travel.
Make sure your Pitch Settings are correct – There are many ways to set up your pitch for your collective pitch helicopter rotors. All of it is based on personal preferences and flying style. However a general guideline would be to ensure that your pitch throws do not exceed the maximum recommended pitch for the helicopter in both positive and negative pitch positions. Make sure that the negative pitch does not exceed maximum when the throttle stick is moved all the way to the bottom and likewise ensure that the positive pitch does not exceed its maximum when you move the stick all the way to the top. For beginners, you might want to set 1 or 2 degrees positive pitch for bottom stick position until you are more used to flying a helicopter with negative pitch or you might get a nasty surprise of “helicopter meets ground REAL FAST” when you redude throttle. Apart from getting the pitch correct for the main blades, ensure that the rotor head paddles are in line with each other with 0 degrees pitch when the swash plate is level. Having positive or negative pitch will only create unnecessary drag and loss of power.

ADVISE TO BEGINNERS: If possible, always get an experienced pilot to help you with your first setup and flight. Even after a helicopter has been properly set up, you will still need to fine tune the trim on the helicopter to make sure everything is perfect. This is where most beginners, especially those who don’t know how to hover yet (even on a properly set up machine) might crash and get disheartened

Choosing a RC Helicopter

Choosing a Helicopter      
For beginners into this hobby, the first question that comes into mind is which helicopter to buy. This is very often associated strongly with the budget available. A word of warning is that this hobby is not cheap by any means. Even if you find purchasing your first helicopter affordable and cheap, you will soon find that repair and maintenance costs will amount to quite a bit. Of course you will also soon learn that the “itch factor” will kick in and you will find yourself spending money on parts, upgrades or even new helicopters just because this hobby is so darn addictive. Anyway you have been warned. Now is the time to read on and enjoy!
Also please keep in mind that even the most experienced pilots will have a crash or two now and then. This could be due to sheer cockiness or lack of concentration or even mechanical failure when flying a helicopter. Replacing parts on a precision machine could really run up your budget. If you are cost conscious then a good place to start would be a .30 size engine helicopter with collective pitch and good availability of parts.

 Raptor 30Deciding on your first helicopter can give you a migraine. You can basically choose from two types of helicopters; a collective pitch or a non-collective pitch machine.
A collective pitch machine basically means that the pitch of the rotor blades changes according to your throttle/pitch stick position. A non-collective pitch machine means that the blades are of fixed pitch and the lift of a helicopter is basically controlled by increasing or decreasing the speed at which the rotor turns.
To the beginner, a collective pitch machine is harder to set up but is easier to fly because it can maintain constant head speed all the time which means control is always there regardless whether you are ascending or descending. The collective pitch machine is also more expensive due to more moving parts and the requirement to have an added servo for pitch control. A collective pitch machine is always recommended for beginners but if budget is a limitation factor, you can always learn to fly on a fixed pitch machine like I did on a “Mini Dragonfly”. Additionally the collective pitch machine will allow you to develop your flying skills without having to upgrade from a fixed pitch machine later on.

    Quick Lesson on Head Speed & Control: The faster a set of rotor blades spin, the better response you will have from the cyclic controls. For a collective pitch machine, you can set the rotor to spin at a certain fixed rate e.g. 100% throttle and yet have the helicopter remain on the ground by having 0 degrees of pitch on the blades. Normally this does not happen but it just basically illustrates how a collective pitch machine is different from a fixed pitch machine which will take off even before you hit the 100% throttle position. You can never change the throttle & pitch combination. To descend on a Fixed Pitch helicopter, you will have to reduce throttle to reduce the rotor head speed which is equivalent to lift. This in-turn will effectively reduce the amount of cyclic control on the helicopter thus making it more sluggish. This is the main reason why it is easier for the beginner to learn to fly on a Collective Pitch Machine.

In addition to the helicopter type (Collective & Fixed Pitch), the size of a helicopter will dictate the stability and reaction time for each model. Generally the bigger the helicopter, the more “stable” the craft, especially in stronger winds. Small micro / mini electric helicopters will definitely be more twitchy as compared to the larger gas powered ones. The sheer weight of larger machines normally weighs down the machine making it more sluggish and allowing beginners to have more reaction time. However larger machines are by no means sluggish as the power plant is normally more than enough to make them perform the wildest acrobatic maneuvers. The ability of each helicopter to perform stunts depends on the design of the craft in addition to the power plant it has.

OS .91 Heli Engine An engine for a helicopter is similar to that of a model aircraft engine. The only difference is the larger heat sink on top of the engine for better cooling. Model Engines normally will require model fuel and a host of other accessories to start, run and maintain the engines (e.g. electric starters & etc)
Motors that comes with electric model helicopters are normally “Brushed” Motors. These tend to wear out relatively quickly and you will find that you will need to upgrade to “Brushless” motors (along with brushless speed controllers) if you’re really serious about flying and wish to put the helicopter through its many hours of flight. For better long lasting flights, people normally use lipo (lithium polymer) batteries as opposed to Nicad / Ni-MH batteries. Other accessories like a special lipo battery charger will be required plus the batteries can be just as costly as model fuel since they tend to damage easily under excessive current load or drainage.

JR Propo PCM 9XII Controller Helicopter Radios are different from Aircraft radios in many ways. The most obvious is the capability of Helicopter Radios to electronically mix certain functions like pitch and throttle (via curves or points), tail rotor and throttle via Revo Mixing. Most radio these days have different modes that allow a modeler to switch between Airplane, Helicopter and Glider Modes like the JR 9XII Radio that I have. Most radios also hold quite a number of model memories which means you can use the same controller with different models that you own. All you would need are extra sets of receivers and servos.
Different radios come with different servos & receivers. Some even come with nicad battery packs while others don’t. It is important that for helicopter radios to have servos with output shafts that are ball-bearing driven to reduce friction under heavy constant usage & vibrations from a helicopter. Speedy servos are also important for increased response times especially for the tail rotor control which is normally connected through gyros. Many helicopter radios come packaged with five ball bearing-ed servos and a large batter packs to handle the extra load and movements on servos.
Futaba S 9252 Hi-Torque Ball Bearing Servo The things to look out for and to have in a helicopter radio would be:

  • Ball-Bearing Servos (5 Servos are needed: Throttle, Collective Pitch, Tail Rotor, Cyclic Left/Right, Cyclic Forward/Backward)
  • Large capacity receiver/servo battery packs 1200mah or more
  • Minimum 5 points Throttle & Pitch Curve settings
  • Throttle Hold Capability
  • 3 Flight Modes (Normal, Idle Up 1 & Idle Up 2)
  • Revo Mixing
  • PCM / PPM Receiver


 Just like other equipment on board a helicopter, the gyro is perhaps the most important aid equipment that will help a modeler pilot his helicopter. A gyro is basically an electro-mechanical device used in a helicopter to help stabilize the tail of a helicopter during flight. As with all gyroscopes, it aids by detecting unwanted movements around the yawing axis. An unwanted right handed swing of the chopper will be countered by a left input of the tail by the gyro to maintain heading of the chopper & vice-versa for a left handed swing. Swings about the main shaft axis normally occur when a helicopter powers up or down due to the torque of the motor and rotor blades.
A gyro is a device used to correct such unwanted swings and is normally attached electronically in between the tail servos that control tail pitch and the receiver. A sensor, either mechanical or peizio in nature, will measure unwanted change in yaw of the aircraft and will correct the situation by increasing or decreasing the tail rotor pitch to stabilize the movement.
Flying a helicopter without a gyro will definitely be a handful and quite a challenge even to more experienced pilots.