Designing and Building Model RC Warships E-Book

Glynn Guest

• Herausgeber: The Crowood Press
• Kategorie: Lebensstil
• Sprache: Englisch

Seitenzahl: 221

Veröffentlichungsjahr: 2024

Beschreibung

Warships are often appealing subjects for working models, especially if there is a personal or family connection with a vessel. However, models based on warships can have a reputation for being difficult to build and safely operate. This can be avoided if the idea of 'Stand-Off Scale' is used. This is where the model will have the appearance of the full-size when sailing, but is a practical working model boat. To successfully build this type of working boat and minimize the problems that might occur, it is important to have some understanding of how such ships work. With this in mind, this book not only details all the information needed to design, outfit and operate a model warship, but also supplies information about how the boats operate.

Leseprobe

Contents

1 Introduction

2 Size and Scale

3 Hull Materials, Tools, Adhesives and Joints

4 Motive Power

5 Radio Control

6 Designing the Hull

7 Building Hulls

8 Different Hull Forms

9 Internal Outfitting and Test Float

10 Sides and Superstructures

11 Adding Details

12 Painting

13 Preparing to Sail

14 Sailing

15 What Next?

Resources

Index

Chapter One

Introduction

The urge to create something new and original is a common one and people usually find this to be a rewarding challenge. If you are lucky then you may have a job that involves this sort of work and actually pays you for doing something you enjoy. However, most of us are not so lucky, but there is always the option to take up a creative hobby.

Building reduced-scale models has a long history. Our ancestors, as soon as they learned to shape materials, started to make models of things like figures and animals. This could have just remained an artistic activity but they also had an educational value and became toys for the young to learn about the world. It was not hard to recognise that they could also be useful in science, technology and engineering. The scale may have been reduced but they could often prove that an idea or technique would work or not. This would be a much quicker and cheaper way to find and solve any problems before starting on the real thing. This is especially true of anything dynamic, such as vehicles, where small changes can have significant effects on the safe, reliable and economic operation of the full size.

A static model, no matter how good it looks, can lack the appeal of one that can move in a realistic fashion. The earliest model boats that could actually sail like the real thing would have been based on vessels with sails, wind being willing to move boats no matter their size. The advent of power sources small enough to fit inside a model boat, like clockwork, steam and electric motors, opened up the potential to make working models of virtually every type of vessel. Radio control then allowed these models to be fully under the command of the operator.

Now you can buy a model boat ‘ready to run’ – just charge the batteries, drop it in the water and sail off. This can give you pride of ownership and operation but not much of the creative satisfaction we first talked about. Many people build a model from a commercial kit or a published plan. This certainly needs involvement that is more personal and hopefully generates greater satisfaction of the ‘I made it’ kind. However, there is often the desire to build a model for which no commercial kit or plan is available, a truly original piece of work.

Models based on warships are often regarded as ‘difficult’ things to build and to safely operate. Some people build warship models that are of ‘museum quality’ with every little detail visible, which can take vast amounts of time, skill and money to complete. This is something that not everyone has the inclination to commit to, in what should be a relaxing hobby. It is possible to strike a balance between these demands by adopting the ‘stand off scale’ approach. The model is simplified, but not to the point where it spoils the appearance and sailing performance. Because it is intended to be viewed when sailing, every little detail that could not be seen under these conditions anyway, can be omitted. The result should be a model that you can honestly say ‘I built it all myself’.

Readers might have some relevant experience outside the area of model boating. This would mean that some sections in this book overlap with already developed skills and experience. For example, you may have operated radio-controlled (RC) cars or aircraft models, but it still might be worth reading sections you know something about. Model boats can have their own unique peculiarities – a bit like the people who build and operate them.

RESEARCH

This term can sound intimidating and put otherwise talented and able people off the idea of making a model boat with any pretentions towards being a representation of a full-size vessel. In fact, some characters in this hobby will take great delight in boasting about the amount of time, money and effort they had to spend researching their ‘master-pieces’ before they could actually start to build it. It might be best to leave them in their world, as we are aiming to produce a stand off scale (SOS) model that, with much less heartache (physical, mental and financial), will result in a model that looks the part and you can enjoy sailing without worrying about the investment.

Partially built model based on Huascar warship and reference materials used.

TWENTY YEARS AGO

Things are somewhat easier now with the vast amount of information available via the Internet, not so when the idea came to make a model based on the Peruvian turret-ram ‘Huascar’. It had a very different appearance along with an intriguing history. She was built in England in the 1860s for the Peruvian navy; at that time, many South American countries were trying to establish their independence from Spain. While the Huascar arrived too late to join the conflict with Spanish forces, its crew were involved in a revolution in Peru and became somewhat piratical. This resulted in two Royal Navy vessels having an inconclusive battle with it. Later, during hostilities with neighbouring Chile, the Huascar was captured and incorporated into the Chilean navy, where it remains to this day. Luckily, in 1971 she was restored, which was quite a task as there was, understandably, little reference material to work with. She has now become a Chilean national monument moored at Talcahuano, much like HMS Victory is in Portsmouth.

Designing a model of Huascar created the same problem that the restorers faced – the lack of sufficient details. The best found were simple sketch drawings of the outline, some internal details and a basic deck plan. This showed that a viable model could be made, but left many puzzling areas. Historical references only had illustrations of limited detail, not helped by the numerous changes that it had undergone in its long history. For example, it had been fitted with an extensive outfit of sails and rigging during the delivery voyage from England, wind power being essential to supplement the modest 300 tons of coal it could carry for the steam engines.

All this was rather frustrating; the real thing existed several thousand miles away, but my hobby budget would not stretch to a visit to take all the photos needed to fill these gaps. In an attempt to locate more information, I wrote to the Chilean Embassy in London, explaining my problem and asking if they could point me in the direction of better information. An encouragingly prompt response came with the promise of further help and this arrived within a couple of months. The Chilean Naval Mission had obtained two tourist guides for visitors to the Huascar. These were in Spanish, but no translations were needed as they were beautifully illustrated and answered most of my questions.

Completed model of Type 23 frigate along with the references used.

A LITTLE BETTER NOW

When I came to build the Type 23 frigate there was much more information available. Collecting information was started a couple of years before any building commenced. As a result, a folder contained several magazine articles and a couple of Royal Navy recruitment booklets. The latter might be an easily overlooked source of very valuable photographs, freely available, but if you go into a recruiting office, modellers that are more senior might first want to explain that they are not thinking of joining the Navy!

The Internet threw up some highly detailed plans of these vessels but with a price to match. As an SOS model was being contemplated, buying these plans did not seem justified, as they would possibly double the building cost of the model. A few simpler drawings and photos on the Internet were sufficient to supply the basic proportions and layout of the Type 23. If there is a moral in this experience, it is not to rush into a project, but to start collecting useful material for as long as possible and keep your eyes open all the time. An example of this was the chance discovery of a book (The Model Ship by Norman Napier Boyd – ISBN 1 85149 327 1) that contained photographs of Type 23 models.

GOOD BOOKS

It might seem that the Internet could supply all the information you might need to build a good model. Just put the name of a vessel or class/type into a search engine and a flood of potential sources might emerge. You need, however, to exercise a degree of critical judgement as some could be limited in accuracy and value. Nevertheless, it is often possible with the right search criteria, to find a ‘gem’ or two.

Discount book collection used for some models.

Books might be considered as ‘old hat’ to many, but a book should have gone through many cycles of rewriting, checking and editing before it reaches your hands. This ought to mean that its content can be trusted to be accurate. Luckily, there are many books written on the subject of warships and ships in general. Possibly a touch ironically, the Internet can be very good at locating just the right book to meet your needs when planning to build a model. Some websites give you a preview of a book’s content, which can help, especially if you are looking for features like scale drawings. Discount bookstores can sometimes be a treasure trove for reference books; there are a few that I cannot pass without going in, and over the years I have found some unbelievable bargains.

There is also the public library system to consider. While a local branch may only have a limited stock, if you become a member, then you can access the on-line catalogue, with the potential to borrow a book from anywhere in the country. Using an author’s name or subject matter can locate a surprising range of books. This is especially valuable if the book you want is out of print, rare or perhaps too expensive to buy. My small local branch library has yet to let me down when ordering such items. Finally, books and book tokens make good birthday and Christmas presents, perhaps more welcome than another item of clothing.

A bibliography is included and is based on the books I have in my possession. It is not intended to be encyclopaedic, but to give you an idea of what is available. Also, using these authors’ names when searching can lead you to much useful material.

Plastic kits can be a good reference for larger working models.

PLASTIC INSPIRATION

Another possible item to help with designing a working model could be one of the small plastic construction kits. Even at a much smaller scale such as 1/600, the manufacturers take great care to achieve accurate shapes. This can be used to get the correct proportions for a larger model and illustrate the sometimes complex areas on the full-size vessels.

Some kit instructions also include useful drawings and painting details. These, combined with good photographs of the real things, are often enough to make a realistic working SOS model. Good enough for the majority but, of course, never enough for the aesthetes and purists that may lurk around the lake, but then nothing ever is.

TELEVISION AND FILMS

Many would consider these two media to be at best entertaining diversions (at worst mind dumbing), but they can occasionally be a very useful source of information. This was brought home to me when I chanced upon a TV programme about chaplains in the Royal Navy. It was based upon a chaplain’s first posting on board a ship, which just happened to be a Type 23 frigate. While an interesting subject in itself, many of the background images were a godsend for anyone building a model of these vessels. Alas, a little too late for me as I’d more or less completed my model!

Chapter Two

Size and Scale

Having decided which vessel they plan to base their model upon, an inexperienced person might then rush into designing and building it. This can lead to problems, which might not become apparent until much later, possibly just as the model is being prepared for its first sailing.

SCALE MATTERS

Scale in this sense simply refers to the ratio of the model’s size compared with the full-size item. It is usually quoted as a fraction, for example 1/100 means all items on the model have been reduced to a linear one-hundredth of the full size.

You could build a model to any size you fancy, but there are some scales that have become popular with modellers and manufacturers. Even when building your own original creation, it can sometimes be handy to use suitable commercial items. Table 1 lists a range of popular scales and the modelling areas in which they are commonly found; this should not stop you ‘borrowing’ them for your model.

Table 1 Common scales used in models.

Scale

Model Type

1/24

G Gauge Railway

1/32

Military + Plastic Kits

1/35

Military + Plastic Kits

1/48

O Gauge Railway + Plastic Kits

1/64

Die Cast Cars

1/72

Plastic Kits

1/87

HO/OO Gauge Railway

1/96

Ships

1/144

Plastic Kits

1/160

N Gauge Railway

1/192

Ships

1/220

Z Gauge Railway

Plastic aircraft kits of the right type and scale have saved me lots of anguish when outfitting the flight decks of aircraft-carrier models. The thought of making from scratch such numerous and very obvious things that have to look identical does not bear thinking about.

Well-populated aircraft carrier flight deck.

Anchor chain from cheap jewellery.

Even a little bit of lateral thought can be handy, such as fashion jewellery, which can make anchor chains, not perfect maybe but close enough and painless. There are also many small businesses that can supply scale details and fittings for this hobby, usually at these common scales. Therefore, choosing a scale for your model, even if it is an original design, that matches or is close to one of the common commercial scales, does make sense.

Slightly over-scale ladders.

These scales might seem to have ‘odd’ numbers like 1/96 rather than the neater looking 1/100. This is due to their origins, which might have a practical rather than a coldly logical basis. The multiples of twelve are related to the imperial units of twelve inches to the foot. Thus, a scale of 1/48 can be expressed as one inch equals four feet or 48 inches. To be honest, you can usually mix near scales without causing visual offence. A personal dislike is making ladders – the model railroad scales can provide suitable items. N gauge railway ladders (1/160) have often adorned my 1/144 scale models and no one has yet noticed this scale mismatch!

Series of warship models built to a common scale.

A further consideration could be if you plan to build more than one type of vessel to a common scale. Coming into this hobby via model aircraft made me familiar with building models using balsa sheets. It seemed sensible to continue with this material and so early models based on destroyers were sized to fit the standard balsa sheet lengths. This worked out to be around the imperial scale of one model inch equalling twelve full-size feet or 1/144. This produced practical models that performed well, not too expensive and, as found out after building quite a few, easy to store. Only later did it become apparent that this scale would allow me to build a range of warship models.

Table 2 Comparison of the effects of differing scales on the size of a model.

Table 2 shows the effect of scale on three common types of warship. It ought to be clear that the 1/96 scale makes a practical destroyer model, the cruiser is becoming a handful, but the battleship would be quite a challenge to transport, let alone getting it in and out of the water. At scale 1/192, things are turned around with a manageable battleship model, the cruiser is fine but the destroyer has become a featherweight – possible, but quite a challenge, unless you accept sailing in only calm conditions. When built in 1/144 scale, the destroyer is a useful size and you do not need to be a weightlifter to cope with the battleship. This admittedly fortuitous discovery has been proven with models based on cruisers and aircraft-carriers built in this scale, but I have yet to build a battleship model.

STABILITY (OR HOW TO REMAIN UPRIGHT)

It is worth spending a little time on how boats, model and full-size, manage to float and to know which way up they should be floating. Not essential knowledge, until you have problems.

The model’s operating weight (often-termed displacement) is perhaps the best thing to calculate first. Boats, model and full-size, float due to Archimedes’ principle, which is, as the hull descends into water, it ‘pushes’ (displaces) water out of the way. The water pushes back with force equal to the weight of water displaced (up-thrust). Hopefully, the weight of water displaced will match the model’s weight before it submerges. This is a stable position: push the model down and the up-thrust exceeds the model’s weight, so it rises back to the equilibrium position. This explains why models sink lower in the water as more weight is added to them.

Why boats (model and full size) float.

Movement of centre of buoyancy corrects bows going downwards.

It also shows why models are stable, even if there is apparently more of the model above than below the waterline around the hull. Two ‘centres’ are needed to explain this. The first is the centre of gravity, the point inside the model around which the total weight acts. The centre of buoyancy is the point inside the hull where the up-thrust force acts. It is the position of the displaced water’s own centre of gravity. When the model is trimmed to float level, then the upwards’ and downwards’ forces are directly in line and in equilibrium. This is the same situation as a ‘see-saw’ being balanced on its central pivot.

Should the bows of the model be pushed downwards, then more of the forward section of the hull is immersed. This moves the centre of buoyancy forwards and now the up-thrust and weight, which should not move, act to rotate the model back to the level state.

Stability tested by heeling the hull.

Transverse stability can be a problem and sometimes you can witness someone’s pride and joy rolling from side to side, as it sails along, possibly with any spectators wickedly watching to see if it turns upside-down. A test that I give to every new model is to roll it by pushing down on the edge of the deck until it is at the level of the water. Upon releasing the model, it ought to spring smartly upright, probably oscillating a few cycles, before ending back upright. This has always been proof that the model has adequate transverse stability and, unless I sail it in stupidly rough conditions, no problems will occur.

Most people will realise that this stability requires the model’s centre of gravity to be low, but are surprised that it can still be above the centre of buoyancy. This sounds like an unstable situation as, when rolled, weight pushes down, while up-thrust pushes up, and it seems like it ought to carry on rotating.

The important thing is that rolling the model immerses more of the hull on the lower side, while reducing it on the raised side. This moves the centre of buoyancy to the lower side and the up-thrust, combined with the weight force, ought to act to restore the model to the upright position.

At rest with the centres in line.

Centre of buoyancy moves to low side and the out-of-line forces roll the hull back upright.

It is worth mentioning two terms that are important for transverse stability: the metacentre and the metacentric height. The former is the notional point on the vertical centreline of the hull about which the centre of buoyancy appears to swing as the model rolls. The metacentric height is the distance that this metacentre is above the centre of gravity of the hull. This has a positive value if the metacentre is above the centre of gravity, positive being stable and good. If the metacentric is below, a negative value is used because it is unstable. The metacentric height of a model can be found from a simple inclining experiment, but successful operation of a model does not need the knowledge of its value. However, what is desirable is an understanding of its existence, plus ensuring that your model has an adequate positive value.

Centre of buoyancy swings about the metacentre.

All of this goes to show that for a given depth of hull immersion, a wider beam of model will be more stable as the centre of buoyancy will move further to the low side for the same angle of roll. However, for all models it will pay to keep the centre of gravity low, everything above the waterline as light as possible and internal weights low.

PRECAUTIONARY CALCULATIONS

Some people avoid mathematics like the plague, but a few simple calculations before starting to make any working model of your own design can save a lot of heartache. For example, will it float correctly, can all the planned internal items fit inside the hull, and can it even be transported to the lake and launched safely? The most extreme size problem can be a model built indoors, which is then found to be too large to move outdoors without some unwelcome structural changes to the model and maybe house.

Block coefficient – the fraction of a rectangular block that the hull just fits inside.

You could be put off by trying to use techniques used in full-size boat and shipbuilding, where accurate results are vital and demand complex methods. With our models we can relax a little and simply settle for a reasonable estimate using the ‘block coefficient’ and water density. You take the length, beam and draught of your hull; multiply them together to give you a ‘block’ of water that the underwater part of the hull will fit into. The block coefficient is simply the fraction of that block that the hull will actually occupy. For slim vessels (like fast warships) this fraction might only be a half (0.5) but for ‘tubbier’ models it would be more. Using this figure multiplied by the volume of the ‘block’ of water, you have the hull volume, which if then multiplied by the density of water (appropriate units of course!), gives you an estimate of the model’s weight.

Experience with many models based on displacement vessels has shown that if using inches to measure the hull and get the value of the ‘block’ in cubic inches, then multiplying this by ⅜ (0.375) it will produce, if not a perfect value, at least a good workable estimate of the model’s probable weight in ounces. The ⅜ (0.375) being a product of an average block coefficient and the density of water. If using metric units like centimetres and grams, then a different number would be needed; my rusty maths suggests it ought to be around 0.67 with these units.

This simple weight calculation proved invaluable with the Huascar model, as my warship models are often built at 1/144 scale. However, at 1/144 scale, a Huascar model’s length would be 40cm (16in) with a weight of 0.6kg (22oz), which seemed to be uncomfortably small. Going up to the next popular scale of 1/96 gave a more promising length of 60cm (24in) and a weight of 2kg (72oz). But, 1/72 scale with a model length of 81cm (32in) and 5kg (174oz) looked to be a much safer bet and more impressive.

The Type 23 model’s scale was already fixed at 1/144, so that it would be compatible with my other warship models. This gave me a model length of around 91cm (36in) and a 1.8kg (64oz) weight. This was much more comfortable and well within my successful experiences.

These simple calculations before building also allow you to ‘play’ with the effects of small changes. You may feel that the planned model length is fine (fits in the car?), but wish for a little more internal space or greater weight. With an SOS type of model, you can often get away with small changes to a model’s beam and underwater draught. A quick piece of arithmetic can show you how much can be gained by these changes before committing yourself.

SUMS FOR SPEED

Powering a new model is often a problem if you want to achieve a reasonable scale-like performance. Those who feel the need to impress or maybe intimidate others, will no doubt just stick in the biggest motor and as many shovelfuls of batteries as possible.

Many people are puzzled that when operating a scale-model boat, if you just multiply the full-size vessel’s top speed by the scale, it can look way too slow. An example is something like a ship with a top speed of say 24 knots (kn) (a knot is one nautical mile per hour or about 51cm/s or 20in/s). This means the vessel moves forwards around 1,200cm/s (480in/s). If a model is built to 1/100 scale and you multiply these values by this scale, it will cover 12cm/s (less than 5in/s). This would produce the same time for both the full-size and model to pass a fixed point. In many people’s eyes, this is acceptable, but when sailing at a distance away from any fixed reference points, it can look slow. The model fails to create a wave pattern that matches what you would expect the full-size vessel to generate at 24kn. You may have to look for a second or two before it is clear that the model is actually moving at all.

This problem was quickly recognised by film-makers when attempting to make realistic action scenes using scale-model boats (a lot cheaper than using the real things, especially if they wanted to sink them). They ran the cameras at a faster speed than normal, so that when the film was played back, the wave and model motions looked much better. We can do the same by running our models at the ‘dynamic scale’ speeds, which produce the same wave patterns. This is based on the work of the nineteenth-century engineer William Froude and others when developing the theory of scale-model testing in naval architecture.