Short Finals No.5

DB or not DB

It is very curious just how many times the combination of the letters 'D' and 'B' may be found in the model flying world. The thought was prompted by the appearance of the Sanwa 'DB Laser' R/C outfits which contain no explanation whatever as to just what the 'DB' stands for. This started a long line of conjecture which continues to grow.

Was it perhaps a tribute to the editor of a certain modelling magazine with the hope of some free advertising as a reward. There is another magazine in the same stable which also has a 'DB' as the editor which makes the idea seem even more plausible.

Then of course there is the 'DB' who stands on top of an ancient van in all weathers and amuses the public while model flyers creep by pretending to be someone else in the vain hope that they will not be noticed. But then he would never stoop to blatant commercialism, so scotch that one.

Another 'DB' used to produce kits somewhere in darkest Northants, while a distant cousin of his who has not been heard of for quite some time used to live in Majorca and write for the model mags.

I wonder if Sanwa can have heard of the 'DB' who lives in Muswell Hill and produces vast quantities of vintage models while simultaneously dispensing plans to all and sundry. It seems doubtful, but you never know.

It does seem unlikely that its a salute to the 'DB' who works at MacGregor Industries, after all he sells JR equipment!

My favourite theory is that it is an appreciation of the man who used to build very early proportional R/C equipment - the DB 'Quadruplex' - in the USA. It could even be the 'DB' who is now arguably the top aerobatic flyer in that country. He also produces the software for the computer flight simulator seen on the Argus stand at Sandown.

Yet another 'DB' is well known for his scale plans service and used to be a well-known competitor in scale contests. He too has been known to contribute to the magazines.

Wait a minute now, there used to be a 'DB' who kept a model shop in Watford and was renowned for his genial nature and cheerful advice. Perhaps it's a tribute to him.

Strange though really, I always thought that 'DB', or more correctly, 'db' was an abbreviation of the word decibel, which is a measure of the amount of noise produced by something.

Multiple redundancy?

For some four years or so I have been flying a 35MHz FM outfit produced not a million miles from Watford. The original receiver supplied with this outfit has been flown in several pylon racers and has latterly been used in a helicopter without any problems. However, a few weeks ago it gave a couple of glitches.

This did not worry me too much since I was flying on 68 at the same time as another flyer on 69 which, even with modern equipment, is pushing your luck.

A couple of days later the receiver glitched again while I was flying with the field entirely to myself. Always being one to heed the gypsies warning, I paid a visit to the manufacturer to have the receiver checked over. It was soon discovered that tuning one particular coil of the receiver produced no result whatever. Investigation revealed that there was no power supply to that part of the receiver due to a wrongly placed component.

The particular part of the circuit concerned is what is known as an RF amplifier and its purpose is to amplify the signal from the aerial before passing it on to the receiver. In this instance it was supplying a drop in the signal rather than an increase.

So who needs it?

I am not programmed to respond in that area

It can not have escaped your notice that the microprocessor has now entered the model R/C world (whoops - I nearly said R/C model world!). No, I don't mean that all the model writers have bought wordprocessors, I am referring to the various interfaces at each end of that tenuous RF link that we try to control our toys with.

In the computer world it is rapidly becoming standard practice to charge the customer for lessons in how to use the equipment that he has just paid an arm and a leg for. This must be the ultimate in 'con' tricks and we can only hope that it does not spread to the R/C world. Having said that, there is certainly going to be a need for some sort of training scheme.

One recently introduced set of equipment has a liquid crystal display which refers to the rate switch settings in terms of percentages. All very well, perhaps, if the maximum travel available was 100%. In this case, however, 100% refers to the throw already set on the end point adjustment. To make things even worse, the rate switch can be set to give more throw than the end point setting.

If you are still with me, consider the following:-

If the end point adjustments are set to different figures in each direction - say more up than down - both of these settings are referred to as 100%, although they are not the same!

The end point adjustment itself uses a number between 0 and 255 to set the amount of movement required. However, if you do not set the travel it will 'default' to a figure which gives two thirds of the maximum travel available - or from position 42 to position 213.

In the immortal words of Dave Day, "If you are confused - so am I".

Quote of the month

A little girl, the daughter of a well-known modelling writer, accompanied her dad to a major trade show (not for the first time). On returning home, she was asked by her mother (another well known trade show attendee) just who she had met there.

"Well," she replied, "there was big Uncle Dave with a beard, Uncle Dave from the magazine, Uncle Derek from Solarfilm and that pillock with the duck!"

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