The 'PCM10' first appeared around 1988 and remained unchanged until the appearance of the 'S' version in 1993. This introduced the 'S' type '10 bit' encoding system, three more model memories and three more programmable mixers. It also sorted out some of the minor bugs in the original software, like the fact that the stopwatch function was cancelled when you left the introductory screen.

The 'SX' version continues this trend and there are now further software refinements. One welcome modification is that four of the programmable mixers are of the 'multi-point' type. This means that you can vary up to seven points on the mixing 'curve'. This is most useful when you program your own tail mixing, for example, or when used with the new JR carburretor. The 'freeze' option, which allows you go into the transmitter programming without stopping the motor in the model has been extended to cover more features, including all eight programmable mixers.

The most obvious new feature is the addition of two more 'Idle-up' conditions. The term 'idle-up' has become redundent and, since the original 'PCM 10', JR now prefer to call these conditions 'Flight Modes'. Thus, we now have a total of seven flight modes available: 'Normal', 'Stunt 1', 'Stunt 2', 'Stunt 3', 'Stunt 4', 'Hold' and 'Invert'. Each of these modes can now call up rates, mixing, pitch and throttle curves, gyro gain and tail pitch curves by operating a single switch - well almost.

The two extra modes, 'Stunt 3' and 'Stunt 4', are actually selected by using the existing 'Stunt 1' and 'Stunt 2' selector switch in conjunction with a second 'enabling' switch , which can be either the 'Gear' switch or the 'Aileron D/R' switch. Thus, to go from 'Stunt 2' to 'Stunt 3' you have to operate two switches! You obviously need to fly the system to fully appreciate this, but it seems to be an awfully clumsy arrangement.

Another new feature is that you can now add 'exponential' to the pitch and throttle curves. this means that, having programmed in the basic curve that you require, which may be a jagged 'dogleg' shape, you can turn it into a nice smooth curve by adding exponential.

The continuing development of gyro systems has prompted the addition of more choices of gyro gain. When used with a linear type gyro (gain proportionally ajustable from the transmitter) you can set three different gains, any one of which can be automatically called up by the flight mode switch.

Well, actually you can only purchase the system as a transmitter/receiver 'combo', although the first batch will also include an aluminium carrying case. On later batches, this will be an extra. You can use the system with all of the vast collection of JR servo types and most (though not all, alas) previous receivers.

Obviously, for review purposes, we needed a complete system and the set received included four of the new NES-4000 'Super Servos', plus an NES-4231 as a throttle servo (don't be jealous, we were given four weeks to return it), plus a 1300 mAh battery pack, all the usual hardware and a set of very nice English instructions. This represented what the manufacturer regards as a typical set, but at around £1600 it is unlikely that many would be sold in the UK.

This is of the familiar JR construction, based on an aluminium extrusion with plastic side plates. The upper half of the front panel, including the stick bezels is in metallised plastic, as is the rear panel. The plastic side panels have soft rubber inserts and there are shaped rubber strips which can be attached to the rear to produce a very comfortable 'wraparound' shape.

The rear panel accommodates a plug-in RF module and a removeable cover which allows access to the battery which is a 700mAh nicad. Below the RF module there is a socket for theDSC/data transfer lead.

At the top of the two side panels there are auxilliary control levers. That on the left trims the low pitch end point (Flight Mode N only), while the right hand one trims the high pitch end point (ditto). Also on the right hand panel are the charging socket and a potentiometer which adjusts the contrast of the information display.

On the case top there are two switches on the left and two switches on the right. At the left side, the front (three position) switch is the Flight Mode switch, while the longer rear switch is the GEAR/INVERT switch. On the right, the longer rear switch is the THROTTLE HOLD switch, while the shorter three position front switch is the rudder dual rate switch (identified as RUDD D/R - it is interesting that when there are three rates they are still referred to as 'dual rates'). The rudder dual rate switch also operates auxiliary 3. This was a Mode 2 transmitter and I assume that Mode 1 sets have the Flight Mode and Hold switches transposed - though I have no way of checking this. Also on the top panel is a ball-jointed adjustable aerial. The aerial itself can be removed and stowed inside the case via a hole in the right hand side panel.

Just in case you are totally confused by now, the front panel has been left till last. There are the usual two dual-axis control sticks with separate electrical trims. The sticks are ajustable for length and tension, while the trims have an extra notch in the middle of the throw which allows this point to be found by 'feel'.

Above the sticks there is a meter which now, alas, only indicates battery strength. On each side of this there is an auxiliary control knob; HOVERING THROTTLE on the right and HOVERING PITCH on the left. Further to the left, there are two switches, the outer one being the three position elevator rate switch (ELEV D/R). Inside that there is a MIX switch. This provides a manual method of turning the programmable mixing on or off. Note that there are other (automatic) methods to acheive this.

On the right hand side there are a further two switches, the inner one being a switched auxiliary channel (AUX 2) and the outer one being the three position aileron rate switch (AIL D/R). Between the sticks there are two green LED's to show that the power is on, a neck strap anchorage point and the main on/off switch (up for on).

Below all this is the main LCD display screen which incorporates a touch sensitive membrane which serves as the programming input. The points to be touched appear on this screen as highlighted 'flags'. When you first switch on, you are greeted by an introductory screen which tells you the selected model name and number together with the type of encoder which is selected and the total time (integrated time) that that particular model has been used since last reset. Note that there is a separate integrated timer for each model number. You are also told the transmitter battery voltage and there is a display of any process timer that is selacted. In the top right-hand corner there is a single flag marked ENTER.

Touching the ENTER flag on the introductory screen will put you into FUNCTION MODE. This presents you with a set of numbered flags (1 to 8) and a flag bearing the legend D.LIST.

Programming PCM 10 is performed by first calling up the appropriate FUNCTION. This can be done in two ways:
1, a) Enter the number (2 digits) of the function required, by touching the number flags, The name of the Function will appear to confirm your choice.
b) Touch the ENTER flag.

2, a) Touch the D.LIST flag. A 'page' of nine available functions will appear, together with + and - flags.
b) Touching the + will step through all of the available functions in turn. The - will step through the functions in reverse. After the ninth function, another 'page' containing nine more functions will appear. There are three of these pages, plus a fourth page containing the remaining 5 functions.
c) When the required function is highlighted, touch the ENTER flag.

A full list of the available functions and the adjustments which can be performed by each is as follows

FUNCTION 11 REVERSE SW - Reverses the direction of any servo.
FUNCTION 12 TRAVEL ADJUST - Sets the throw of each channel in each direction. Max. 150%,
FUUCTION 13 D/R & EXP - Allows 3 different rates and 8 types of response to be set for aileron, elevator & rudder channels.
FUNCTION 15 SUB TRIM - Offsets servo to one side. Max. 125%.
FUNCTION 16 THROTTLE HOLD - Moves throttle to a pre-set point.
FUNCTION 17 FUNCTION SELECT - Selects which switch enables Flight Modes 3 & 4, which switch operates the 'Gear' and 'Invert' functions and enables the high and low pitch trim levers.
FUNCTION 18 THROTTLE CURVE - Allows the adjustment of 5 different throttle curves (Flight Modes N, 1, 2, 3, 4).
FUNCTION 23 AUTO DUAL RATE - Allows the selection of 1 of 3 different rates on the aileron, elevator and rudder channels for each flight mode (1, 2, 3, 4 & Hold).
FUNCTION 25 STUNT TRIM - Offsets aileron, elevator and rudder trim for each flight mode (1, 2, 3 & 4).
FUNCTION 28 DATA RESET - Returns all settings to default value.
FUNCTION 41 RUDDER/THROT MIX - Compensates for changing tail load.
FUNCTION 44 GYRO SENSITIVITY - When used with a linear gyro, allows the selection of 1 of 3 different gains for each flight mode (N, 1, 2, 3, 4, Hold & Invert).
FUNCTION 47 REVO-MIX - Changes tail trim to compensate for changing torque.
FUNCTION 48 ACC MIX - Adds an ajustable time delay to REVO-MIX.
FUNCTION 51 PROGRAM MIX 1 - )
FUNCTION 52 PROSRAM MIX 2 - ) Mixes any channel with any other channel.
FUNCTION 53 PROGRAM MIX 3 - ) Linear mix.
FUNCTION 54 PROGRAM MIX 4 - )
FUNCTION 55 PROGRAM MIX 5 - ) )
FUNCTION 56 PROGRAM MIX 6 - ) ) Mixes any channel into any other
FUNCTION 57 PROGRAM MIX 7 - ) ) channel with 7 point curve.
FUNCTION 58 PROGRAM MIX 8 - ) )
FUNCTION 65 SWASH TYPE - Allows the selection of 1 or 3 servos for swashplate operation and allows the ajustment of the swashplate timing to avoid interaction.
FUNCTION 68 PITCH CURVE - Allows the adjustment of 7 different pitch curves (Flight Modes N, 1, 2, 3, 4, Hold & Invert).
FUNCTION 75 SERVO TEST - Cycles all servos slowly over full range.
FUNCTION 77 FAILSAFE - Set individual servos to hold or go to preset position on loss of signal.
FUNCTION 81 MODEL NAME - Records name of model.
FUNCTION 82 TRIM OFFSET - Offsets aileron, elevator or rudder centrs to one side. Does not change end points. Max. 127%.
FUNCTION 83 TRIM RATE - Sets trim travel of aileron, elevator and rudder channels. 0 to 100%.
FUNCTION 84 MODEL SELECT - Selects one of ten different models.
FUNCTION 85 MODULATION - Selects SPCM, ZPCM or PPM.
FUNCTION 86 TRANSFER - Transfers model information to another transmitter via the DSC lead.
FUNCTION 87 TIMER - Resets integrated timer. Enables and sets countdown timer.
FUNCTION 88 KEYBOARD LOCK - Sets keyword to protect information.

Note that TRIM OFFSET does not move the set end points, but SUB TRIM does.

If you want to use the 'S' type modulation, you need an 'S' type receiver. This is the usual JR size and has the servo sockets along one end. Until recently, JR tended to rely on their 'ABC&W' receiver in preference to a dual conversion type, but are now using a dual conversion receiver with the 'ABC&W' circuitry. Presumably, this gives the best of both worlds.

Note that this receiver will only work with the 'PCM 10SX' transmitter.

The 'NES-400 Super Servo' is a new type which is said to give five times the 'holding power' of existing servos. What this means is that the servo circuitry tends to resist any force which tries to move the servo away from the selected position. It is worth pointing out that this does not mean that the servo has more power to assist it to arrive at the selected position. In fact, a study of the manufacturers figures shows that the actual torque available from the servo is quite modest compared with other JR servos.

This resistance to unwanted displacement is acheived by generating a pulse within the servo which updates the information at a much higher rate. Standard servos are updated once each time a 'frame' of information is transmitted. Nominally, this happens 50 times per second. If you stall a conventional servo, it will 'buzz' at this frequency which is close to the familiar 'mains' frequency which dominates our lives. By updating the servo more frequently from its own internal reference it has a stronger resistance to any disturbance. Hence, a stalled 'Super Servo' doesn't buzz.

One result of this is that the servo will tend to hang onto the last known position regardless. If, for example, you turn on the receiver supply without turning on the transmitter, the servo will hold whatever position it happens to be at. This has possible repercussions if you are using a PPM system, since any loss of signal will mean that the servo can go to virtually any position and then hold it. For the moment, therefore, it would appear that these servos are for PCM use only.

Well, just about anything that you can think of, but you may have to do a little tinkering to get there! Just about all of thee better known helicopter mixing options are already set up for you in the form of dedicated mixers. Anything different that you may want can be easily catered for by the eight free programmable mixers that are included. Anyone with a 'Chinook' in mind should have no problems.

All of the main flying controls can have their throw adjusted in each direction, with three different rates available. The rate switches can also call up positive or negative differential, or a dogleg type of response.

The failsafe can set each channel individually to hold its last position, or go to a preset point.

The limits are purely in the capabilities of the user.

While it is not the purpose of this review to present a one-on-one comparison between the '10SX' and its competitors, some comments are certainly necessary. The dedicated contest flyer will find everything that he currently thinks he needs and it is presented in an easy to understand, user-friendly manner. The inexperienced flyer will certainly find it confusing, but it is nowhere near as confusing - or downright intimidating - as some of its competitors. JR continue to use the conventional trim lever, with a helpful centre notch, while at least two competitors now use the so-called 'digital' trim, which this writer finds to be virtually useless (that's a personal opinion, not a criticism)!

The advent of multi-point mixing on all the current sets has a lot of uses - when you get to grips with it - particularly in terms of tail rotor mixing and, with the new JR carburretor, control of fuel mixture.

Where the JR 'PCM 10SX' falls behind most of its competitors is in the area of versatility. The switch set-up that is supplied is almost engraved in stone! There is no choice whatever as to what switch does what. The only choice that you have is in which of a limited selection will 'enable' flight modes 3 and 4 - a most clumsy arrangement anyway. Most of its competitors now allow you to select any switch to perform any function - once you have tried it, nothing else will do!

Finally, you still have to buy either a 'Heli' or an 'Aero' set. This is not going to be a problem to the dedicated flyer, but you are parting with an awful lot of money to fly just one type of model.

I used to think that manufacturers like JR actually read these reviews and took note of them, but that cannot be the case. For some seven years now (as of 1999, make that 12), this writer has been asking why it is that not one radio manufacturer allows you to see both the pitch and throttle curves together on a heli set. The first manufacturer to do this will render all other equipment obsolete overnight!