Trainers, Engines and Radios
The attached notes for new radio modellers are based on my own experiences and prejudices. I hope they are of some use.
Kits for first Trainers
A trainer should be stable, slow flying, well behaved and tough. I recommend that you start with a four channel set-up (elevator, rudder, ailerons and throttle controls) straight away. It should have the following features:
High wing (for pendulum effect stability),
A modest amount of dihedral (further lateral stabilisation)
Light weight (for slow flight),
Tricycle undercarriage (for easy ground handling),
Good selection of materials (for strength where it counts!).
These days it is more popular to start with an “Almost Ready to Fly” (ARTF) trainer. There are good examples from makers such as Kyosho, VMAR, Thunder Tiger, Ready and a number of others. They are less work before you start flying, but perhaps a little more difficult to maintain and repair. Some of the instructions for completing assembly are not comprehensive but we can help you to avoid the pitfalls; if you pick one of the most popular trainers we may even have compiled a set of notes (ask Mick Saxton).
If you enjoy building models, some of the best kits for trainers that are available are:
ATS Kite - good flying and ground handling characteristics.
Cambrian FLYER - well thought out design from a very good company.
MFA YAMAMOTO - good flying and ground handling characteristics.
Others that the model shop may try to sell you include:
Flair Cub - the market leader for a few years - not a favourite of mine, largely because if its poor ground handling properties.
Foss Uno-Wot - an excellent second model, with which you will be able to develop your skills, but not really a basic trainer.
Engines
There are some excellent engines to be bought these days. For flying at Leatherhead you will have to bear in mind our tight noise restrictions. It is better to go for a quiet engine to start with, rather than a cheaper, noisier one, which will need an add-on silencer (which may make it difficult to adjust satisfactorily). All of the four-stroke engines, at least up to 0.70 cu.in size, are quiet enough, but they rather expensive to “risk” in a trainer. The choice of two-strokes is wide and the following are all good:
OS engines produce ranges of plain bearing (LA series) and of ball raced (FX series) quality engines (from Japan). The FX engines are undoubtedly the best two-strokes widely available; powerful, reliable and quiet, but their price is reflective of their quality. The LA plain bearing engines are more economically priced. They are less powerful but very easy and reliable to operate. They are quiet enough without resort to a silencer extension (provided the right choice of propeller is used).
Irvine produce good ball raced (British) engines, which are quiet enough and, in my experience, very reliable. They are less expensive than the equivalent OS, and are very well made. I have had good experience of the earlier range of Irvine engines, including the old Irvine 46 in one of the club trainers. The latest products from Irvine are beautifully made and particular attention has been given to making them quiet.
Many of the club members have the Super Tigres. These Italian engines are also very well made and, because the Italian economy has been weak, they are inexpensive. However, it is my impression that they are trickier to keep going, especially on cold winter days.
I would suggest that, in general, is better to avoid second hand engines, and also the cheaper Chinese and Russian ones (ASP, SC and MDS). You could be lucky and get a good one, but sometimes they are tricky to operate reliably. To be fair, some of the cheaper maker’s new engines appear to be much better than their earlier ones. They tend to be quieter, and easier to set up for reliable running than the earlier versions, but I remain very cautious about recommending them.
Choice of propeller can make a very large difference to engine noise as well as performance. The APC and Bolly sport ranges offer a good balance of quietness and efficiency. Graupner props are also very good but they tend to be a little heavier; the extra ‘flywheel’ effect suits some engines. Some of the other makes are less efficient and give more noise. The instructions with your engine will indicate a range of compatible prop sizes. In order to keep the noise down, you should select a prop from the higher end of the recommended diameter/pitch range.
Electric flight has now reached the stage of development at which it can be considered for training. The elimination of oily engines is the main attraction for some people. However, electric flying is not without its pitfalls and the help and advice of an experienced practitioner will be very useful (preferably before you dash off to the model shop!). Contact Ted Dalley (01372 458782) for such help.
The choice of your first radio is quite important because it will influence any future additional equipment that you buy (if you keep to one make you will have the advantage that all of the plugs and sockets fit and all the components are compatible). The leading makes are all excellent. You will need a four channel set, but may consider it worthwhile to spend the small extra amount for equipment with a couple of extra channels or even one of the basic computer sets. Make sure that you choose a set that feels comfortable to hold.
You must use properly constructed rechargeable (NiMH or nicad) battery packs in transmitter and receiver - no dry cells and no individual cells with spring metal connections. The sets should be bought complete with batteries and appropriate chargers.
For a long time Futaba has been the UK market leader, and many club members use this make. Futaba have the largest range, from basic 4 channel sets (such as the Skysport 4, which we use with a club trainer) to very sophisticated and flexible computer sets. There is an effective service organisation (run by Ripmax). Advantages of choosing Futaba are:
a) extra servos, switches, crystals, etc. are stocked by almost all model shops,
b) we have club Futaba transmitters enabling an instructor to have dual control (via a “buddy box” lead) which is generally better for early training sessions.
JR also make excellent equipment – JR enthusiasts claim that, in some aspects of design, ergonomics and quality, their equipment is even better than Futaba (although some of the circuit boards are identical).
Sanwa probably offers the best value for money currently. The quality of their products is very good, and their entry-level computer transmitter has set a target for the other makers to follow. New Sanwa equipment uses the same standards as Futaba, but older Sanwa sets were not compatible.
Hitec also offer very good value. Their current equipment appears to be comparable with their competitors, but please do not be tempted to buy second hand sets of this make.
Before you buy radio equipment, have a word with the regular fliers about choice of crystals. We have been trying to ensure that we avoid having too many members wanting to use the same channel. Currently we are able to use all 36 channels that are numbered from 55 to 90. To minimise risks of interference, we discourage flying while an adjacent channel is in use and we remain cautious about the risk of a slight problem in the pits (receiver to receiver) with frequencies that are 23 channels apart.
I hope that these guidelines are of some help. They are not tablets of stone and they will quickly become out of date, so please ask questions of the experienced club members. I have never met a modeller who was unhappy to talk about his hobby (obsession).
Happy Landings
Geoff Bignold
last updated 23/11/2002