Having compared the 'PCM 8' - probably unfairly - with the 'PCM 10', lets compound the felony by completing the comparison. The other obvious difference is that it does not have the touch sensitive keyboard fitted to the front of the LCD display. This has been replaced by seven pushbuttons ([Up], [Down], [<], [>], [+], [-] and [CL]) mounted immediately below the slightly shallower display. However, there is a hidden bonus here as you can now adjust the display brightness, or contrast.

When you switch on the transmitter, you become aware that the display is very different and consists of two lines of 16 characters (32 in all) which are about 3/8th of an inch high and very clear and easy to read - a situation which is aided by the fact that you are not looking 'through' the keyboard. Further investigation reveals that there is no programmable mixing, no CCPM mixing and only 3 model memories. There is no 'trim offset' and you cannot program the rudder position when the 'throttle hold' switch is operated.

Having completed the comparison, lets take pity on those who are not familiar with the 'PCM 10' and describe the 'PCM 8' properly.

The transmitter case appears to be a mixture of plastic mouldings and aluminium extrusions. In fact, metallised plastic has become so good these days that it is possible that some of the apparently metal parts may actually be plastic. However, the top, rear and bottom of the case are certainly metal and the front panel may be. Case sides (ends?) are plastic and have an inlaid rubber section with gives a soft feel. Two self adhesive rubber strips are supplied which can be stuck onto the case rear to give a 'wrap-around' effect. The result is solid, chunky and very comfortable.

A solid metal handle is fitted to the top of the rear panel which makes carrying the transmitter very convenient, but may give problems for tray users. The rear panel also houses the plug-in RF module and has a removable cover for access to the battery. This is an eight cell 700 mAH nicad.

Stick units are adjustable for both length and tension, while the trim levers now feature a notch at the travel centre to give a positive indication of this position. The familiar mechanical overtravel of the trim levers has now been discontinued, although this is not immediately apparent, since the new one-piece moulding looks identical.

At the lower edge of the front panel is the previously mentioned display and seven pushbuttons, while at the top there is a large RF meter. This is flanked by a 'hovering pitch' knob on the left and a 'hovering throttle' knob on the right. These are only effective on the 'normal' (N) pitch curve.

Also on the top right of the front panel is a long toggle switch which operates the 'Aux 2' and a shorter switch which selects the aileron dual rate. On the left side is the elevator dual rate switch. At the left side of the top panel there are the 'throttle hold' and rudder dual rate switches. Matching them on the right are the 'invert' switch and the three position ('N', '1' and '2') 'flight mode' switch. The rudder dual rate switch also operates 'Aux 3', which is intended for use with a gyro having a proportional type of gain control (curious this, as JR no longer produce one). When the inverted flight facility is not in use, the 'invert' switch operates the 'gear' function (which is actually the 5th channel, or 'Aux 0', with the pitch channel being 'Aux 1'). This control layout is identical on the 'PCM 8', 'PCM 9', 'PCM 10' and 'Computer 8', although some of the budget JR sets are quite different.

The case sides incorporate 'High' (right) and 'Low' (left) pitch trim levers which can be inhibited if required. These later controls can also be found on all the 'PCM' series, but not on the 'Computer 8'.

In common with many of the lower priced JR sets there are two modes of access:
a) Hold down the [Up] and [Down] keys together and then turn on the transmitter. This gives access to the 'System set-up mode'.
b) Turn on the transmitter and then press the [Up] and [Down] keys together. This gives access to the 'Function mode'.

For those who find the cheaper JR sets confusing or even intimidating, rest assured that the resemblance ends here! In either mode you now have [Up] and [Down] keys which cycle through the various functions (each of which is clearly named) and [<] and [>] keys which select each feature of that function. What's more, say you are setting the dual rate function and are on channel 3 (elevator), stepping down to the next function - which is the exponential function - you will find that you are still on channel 3. Simple, no complicated flow charts to remember and no codes to learn to indicate each function. When you have the feature that you need, [+], [-] or [CL] keys allow you to increase, decrease or reset the value.

'System setting mode' allows you to set-up the following:
SELECT MODEL - Selects model 1, 2 or 3.
NAME INPUT - Allows you to enter the model name (7 characters maximum).
MODULATION - Selects PCM or PPM.
COPY - Copies all information from one model number to another.
RESET ALL - Resets all parameters to default value for a given model number.

'Function mode' gives access to the following functions:
REVERSE - Selects normal or reverse for all 8 channels.
THROW ADJUST - Sets end points, in each direction for all 8 channels. Max 150%
SUB TRIM - Offsets neutral of each channel up to �125% (�30� servo travel).
DUAL RATE - Sets servo movement for each position of dual rate switches from 0 to 100%.
EXPONENTIAL - Sets non-linear servo movement.
THROTTLE HOLD - Selects throttle position when 'hold' switch is operated. Also has 'AUTO-CUT' feature which operates throttle hold automatically at preset point on throttle.
THRO CURVE (NORM)
THRO CURVE [ST-1]
THRO CURVE [ST-2]
- Sets 'Lo', 'Hi' and 3 intermediate throttle positions when 'flight mode switch' is in the 'N', '1', or '2' position.
PITCH CURVE [NORM]
PITCH CURVE [ST-1]
PITCH CURVE [ST-2]
PITCH CURVE [HOLD]
PITCH CURVE [INVT]
- Sets 'Lo', 'Hi' and 3 intermediate pitch positions when 'flight mode switch' is in the 'N', '1' or '2' position, or when the 'hold' or 'invert' switches are operated.
ATS REVO-MIX - Sets 'Up' or 'Down' tail compensation rates, above or below hover setting, between 0 and 100%. Hover position can be anywhere on throttle stick. Separate setting when flight mode switch is in '1' or '2' position varies about zero pitch point. Clockwise or anticlockwise rotor direction.
ATS ACC-MIX - Introduces a variable time delay into 'REVO-MIX'.
STUNT TRIM - Allows trim of aileron, elevator and rudder channels to be offset up to plus or minus 125% when flight mode switch is in the '1' or '2' position.
AUTO DUAL RATE - Allows flight mode switch, or hold switch to select dual rate automatically.
THRO TRIM RATE - Sets throttle trim rate between 0 and 100%.
PITCH LEVER - Inhibits or activates high and low pitch trim levers.
INVERTED SWITCH - Reverses elevator, rudder and pitch channels for inverted flight. Separate pitch curve available.
FAIL SAFE - Controls may be set to hold their last position or go to a preset position. Time delay can be 0.3, 0.5 or 1.0 seconds.
REVERSE - etc.

'Sub trim' needs to be used with care since it is possible to restrict throw in one direction if over-used. It moves the whole of the servo range, including the end point settings. However, it cannot exceed the limits already set by the 'throw adjust' function.

When setting the throttle and pitch curves, the hi and low positions cannot exceed the throw already set by the 'throw adjust' function. This can also limit the effect of the high and low pitch trimmers. To avoid this, you should ensure that the upper and lower limits of the 'pitch curve' adjustment are between about 10% and 90%. If you then need more pitch, use the 'throw adjust' function to obtain this. The three intermediate points occur at the 1/4, 1/2 and 3/4 positions on the throttle stick travel and are not adjustable. They can all be inhibited or moved above or below the normal linear response. This is probably easier to understand than most comparable sets, since allowing you to program points anywhere on the throttle throw (and understanding just how to do it and/or change it) is, perhaps, too much of a good thing.

Note that there is no separate throttle curve for inverted flight. Any of the 3 existing curves can be used and called up by the flight mode switch.

Stunt trim works like sub trim and has the same restrictions.

At the beginning of this article I mentioned a feature of the 'Computer 8' that I would have liked to see retained. This is the ability to increase the throw via the rate switches (more than 100%) or the pitch and throttle curves, rather than having the throw limited by the 'throw adjust' function. Curiously, the other new JR set - the 'x-347' - does have this facility!

It must be pointed out that this does mean that extra care is needed on the 'PCM 8', when setting up, to avoid setting more throw than is actually available. However, in fairness, the facility to increase the throw without having to go back to the 'throw adjust' function is of maximum use when CCPM mixing is used - which is not available on the 'PCM 8' anyway.

The programming system used is very straightforward - as already mentioned. There does seem to be a great reluctance on the part of the average modeller to use computer sets, despite their many obvious advantages. As I do not share this reluctance, I find it very difficult to understand. Granted, some early cheaper sets did use rather convoluted access systems, but therein lies the challenge! The only possible difficulty with the 'PCM 8' could be in the whole concept of using percentages to express the various parameters. Interestingly, many people seem able to grasp the idea quite well if the '%' is simply omitted and it is considered as 'marks out of a 100'. I thought that JR were following this line of thought when they introduced the 'PCM 10'. Perhaps that was the other design department!

At the risk of repeating myself, the virtue of the programming system used is that you do not have to remember which function follows which, or which way round the system you have to drive it to find a given function. You just step through it until you find the one you want - and it works exactly the same both ways. If you go past the required function, you can step back to it or 'go round again'. Each function is clearly named. Try it once and you will be convinced.

Included with the equipment is a neck strap and a set of servo trays. The standard receiver is the 8 channel PCM unit with ABC&W, a feature which appears to have saved JR from following the dual conversion route chosen by others. Servos can be any from the vast range available from this manufacturer, but NE 517's are standard. A 700 mAH receiver pack is supplied together with a dual charger which now has a British three pin plug. Yes, there are English instructions too.

A worthy successor to the 'Computer 8', despite my earlier misgivings. If I needed a new helicopter set right now, I would give this one very careful consideration. It does not have all of the functions which can be found on the most expensive sets, but it has more than the average modeller is ever likely to need. Come to think of it, it probably has more than most modellers can be bothered to use. I like the straightforward entry system, which should help to overcome many modellers resistance to computer sets.

It would have been nice to see more than 3 model memories, but I get the impression that this would have meant a big price increase due to memory limitations. If the original object was to produce a 'budget PCM 10', this may well have been a major factor.

I really can't wait to see what they come up with next!