Introduction

When the engine for a new civil transport, the New Large Aircraft, was considered in Chapters 1 to 10 many assumptions were introduced to make the treatment as simple as possible. In the treatment of the engine for a New Fighter Aircraft in Chapters 13–18 the level of complexity was increased. The properties of the gas were allowed to be different before and after burning of the fuel and the effect of the mass flow of fuel added to the gas passing through the turbine was included. The effect of the cooling air supplied to the turbines was allowed for and the effect of the pressure loss in the combustor was accounted. It is appropriate to recalculate the performance of an engine for the civil aircraft with some of these effects included and that level of fidelity will apply to most of this chapter.

Another difference between the treatment for the civil engine in Chapters 1–10 and the treatment for the combat aircraft was the mixing of the core and bypass streams upstream of the final propulsive nozzle in the combat engine. Some large civil engines are mixed and this chapter therefore opens with a brief consideration of this option. Following this the consequences of different levels of fidelity in modelling will be addressed. A significant part of the chapter uses the most accurate model to look at the impact of cooling air, pressure drop in the combustor and component efficiency on the thrust and sfc of engines; this is done first for the engine on-design and then off-design. The chapter concludes with a brief consideration of propulsion for high-speed civil aircraft.

The benefit of mixing in large civil engines

It has been quite common for large civil engines to have a mixed exhaust, where the core and bypass streams are mixed before the final propulsive nozzle. Indeed, most of the Rolls-Royce RB211 engines were mixed and mixing is still common for smaller engines.

History and regulation

As jet air transport increased in the 1960s the annoyance to people living and working around major airports was becoming intense. Regulations affecting international air transport are governed by the International Civil Aviation Organisation (ICAO), but this body was moving so slowly that in 1969 the US Federal Aviation Agency (FAA) made proposals for maximum permitted noise levels. After extensive discussions in the USA these were formally approved as Federal Aviation Regulation (FAR) Part 36 in 1971, retroactive with effect from 1969, but only for new aircraft. Shortly afterwards the ICAO Committee on Aircraft Noise published similar recommendations, to be known as Annex 16, a formal addendum to the 1944 Chicago Convention on Civil Aviation; each member state had then to accept the rules in Annex 16 and write them into their legal framework. The underlying principle for the noise certification of aircraft under FAR Part 36 and Annex 16 are similar and has remained unchanged ever since, with the levels under the US and ICAO rules subsequently becoming virtually identical.

The certification for noise relies on measurements at three positions, two for take-off (referred to as lateral and flyover) and one for landing (referred to as approach). The levels are expressed in decibels (EPNdB) using effective perceived noise level (EPNL), described in outline below. The layout for testing is shown in Figure A1.

The noise at the lateral position is the highest noise measured along a line parallel to the runway whilst the aircraft is departing at full power and the maximum usually occurs when the aircraft has climbed to about 1000 feet. Flyover noise is measured directly under the flight path after take-off and at an altitude where it is normal to cut-back the power to reduce the noise whilst still maintaining a safe rate of climb. The approach noise is also measured directly under the flight path as the aircraft prepares to land, with the glide slope carefully controlled.

Introduction

The engine requirements for an aircraft depend upon the size, range and speed selected, but they also depend on the aerodynamic behaviour of the aircraft and the way in which it is operated. In this chapter some very elementary aspects of civil aircraft aerodynamic performance are described (if further explanation is needed the reader is referred to Anderson (2011)). These lead to a brief description of the conditions which are most critical for the engine: take-off, climb and cruise. It is possible to see why cruising fast and high is desirable, and to calculate the range. We can also develop the New Efficient Aircraft, the NEA, to form the basis of the exercises in Part 1 of the book. Knowing the ratio of lift to drag it is possible from this stipulation of the NEA to estimate the total thrust requirement.

Payload versus range

It is common to show aircraft performance by plotting maximum allowable payload against range capability, and an example corresponding to the Airbus A330-300 is shown in Figure 2.1. The presumption is that only enough fuel is carried to enable the mission, though reserves are also carried to enable diversions or other contingencies to be handled safely – it is the intention that these reserves will not be used. As the range is increased the weight of fuel at take-off must increase. The maximum payload allowed by the structure is marked by line OA and, as the range is increased along the line OA, the payload can remain constant at its maximum value, despite the increased weight of fuel, until the point A is reached. At point A the total weight of the aircraft has reached the maximum take-off weight and the range for this is denoted by R1. For the range to be increased beyond R1 requires additional fuel but, since the maximum take-off weight has been reached, for extra fuel to be carried the payload must be reduced. Payload may be substituted by fuel in this way until the tanks are full, denoted by point B in Figure 2.1. To increase range beyond that for B implies the drag, and consequently aircraft weight, has to be reduced in order to reduce fuel consumption, and this leads to a steep drop in payload for a small increase in range.

Introduction

The compressor, which raises the pressure of the air before combustion, and the turbine, which extracts work from the hot high-pressure combustion products, are at the very heart of the engine. Up to now we have assumed that it is possible to construct a suitable compressor and turbine without giving any attention to how this might be done. In this chapter an elementary treatment is given with the emphasis being to find the overall features of the compressors and turbines, including the number of stages, the suitable rotational speeds, the diameters and some indication of the flowpath. The details of blade shape will not be addressed. Further information is obtainable in a recent book by Dixon and Hall (2013) and at a more specialised level for compressors in Cumpsty (2004).

The description of turbomachinery is based on the fan, compressor and turbine for the engines of the NEA. To avoid unnecessary duplication, the design is restricted to the case with a fan pressure ratio of 1.5 at cruise. At this condition the stagnation pressure and temperature entering the engine are p02=35.6 kPa and T02=245.4K. From Exercise 7.4 the mass flow through the engine to give the required thrust is 392 kg/s and of this 32.1 kg/s goes through the core (bpr = 11.2 The turbine inlet temperature is 1500 K, the overall pressure ratio is 45 and the HP compressor pressure ratio is 18. From Exercise 7.6 the fan diameter is 2.66 m.

For the large engine that we are considering the most suitable compressor and turbine will be of the axial type. These are machines for which the flow is predominantly in the axial and tangential directions, and stand in contrast to radial machines for which the flow is radial at inlet or outlet.

Because the pressure rises in the direction of flow for the compressor there is always a great risk of the boundary layers separating, and when this happens the performance of the compressor drops precipitously and it is said to stall. To obtain a large pressure rise (or, as it is more commonly expressed, pressure ratio) the compression is spread over a large number of stages.

Introduction

It would be possible to calculate the performance of an engine in the manner of Exercises 7.2 to 7.7 for every conceivable operating condition, e.g. for each altitude, forward speed and rotational speed of the components. This is not an attractive way of considering variations and it does not bring out the trends as clearly as it might. An alternative is to predict the variations by using the appropriate dynamic scaling – apart from its usefulness in the context of engine prediction, the application of what is conventionally called dimensional analysis is illuminating. The creation of groups which are actually non-dimensional is less important than obtaining groups with the correct quantities in them. The reasoning behind these ideas is discussed in Chapter 1 of Cumpsty (2004). For compatibility with the usual terminology, however, the phrases ‘dimensional analysis’ and ‘non-dimensional operating conditions’ will be retained here.

Using the ideas developed on the basis of dynamic scaling it is possible to estimate the engine performance at different altitudes and flight Mach numbers when the engine is operating at the same non-dimensional condition. From this it is possible to assess the consequences of losing thrust from an engine at cruise and, in some cases, to estimate how the engine will behave on a static test bed.

Engine variables and dependence

Figure 8.1 shows a schematic engine installed under a wing. For simplicity this is a mixed-flow engine, where the core and bypass streams are mixed before entering a single propulsive nozzle. Later the treatment can be generalized by considering the two streams separately. Alternatively, with bypass ratios to 10 or more, the errors may not be large if the analysis concentrates on the bypass stream and assumes the ratio of core jet velocity to bypass jet velocity stays approximately constant.

Introduction

In Part II the approach shifts away from the broadly chronological towards the ethnographic. In the previous chapters we traced the changing meanings of race, with an eye to the constant interweaving of ideas of nature and culture, and with the aim of nuancing conventional chronologies that – to oversimplify – traced a broad historical sweep from race as culture, to race as biology, and back to race as culture, with race itself disappearing in the last phase. From this point in the book the focus is on the way racial inequality and racial difference are reproduced in changing ways in everyday practices in specific places. The idea is not to give regional overviews, but to focus on specific ethnographic cases in their regional context. Three preliminary points need emphasis.

Racial categories as relational

First, racial difference is not just about disadvantaged racialised groups, but about a set of relational racialised identities: white, mixed, black, indigenous, Asian, etc. are all equally significant; these categories or identities gain their meanings and power in relation to each other. This emphasis derives in part from recent research focusing on whiteness, as a category or social position that, in the past, has not always received much attention, as the study of race has typically been a matter of white researchers investigating groups seen as ‘other’ and usually disadvantaged or oppressed, a viewpoint that tended to take whiteness for granted or assume its privileged status. Greater attention to whiteness has shown that it is also a historically changing and unstable category – one that, in the United States, for example, during the late nineteenth and twentieth centuries absorbed categories previously defined as non-white, such as southern Europeans, the Irish and Jews (Brodkin 1998; Kolchin 2002; Roediger 2006) – and a heterogeneous one for which privilege is not necessarily automatic (Hartigan 1999).

Racial practices as relational

Second, understanding racial difference and inequality requires seeing race as relational in a different sense and embedding it in a local cultural context, paying attention to class, politics, space, gender, values and morality.

In the previous chapter we were concerned with outlining what ‘race’ means in a way that grasps its variety, while also placing some constraints on that variety to avoid placing too many very diverse eggs in one basket. Some of the features that are often said to define race – the use, by people classifying people, of criteria of physical appearance, nature, heredity, bodily form, biology – can be found in many contexts, lending them some affinity with contexts more typically associated with the idea of race. But it seems unhelpful to include all these very heterogeneous contexts together. Instead, the history of Western modernity, broadly defined, can be used as a thread to string together a specific set of contexts in which race is most helpfully understood as a specific phenomenon.

That thread, however, has to be seen as itself diverse. The usefulness of ‘Western modernity’ as a connector or umbrella should not tempt us into assuming that ways of thinking about physical appearance, nature, heredity and bodies do not undergo very significant changes over time; not to mention the ways of perceiving habit, customs, behaviour, civilisation, morals and culture that always go alongside them in racial thinking. Nor should we assume that the thread has a simple starting point: as I briefly indicated in the previous chapter, the ancient and medieval worlds had plenty of conceptual elements related to all these ways of thinking, even if we decide not to label these as racial.

This chapter explores how ideas about what we can, for shorthand purposes, call ‘nature’ and ‘culture’ have worked together in ways of explaining humans and human diversity. The aim is to describe the conceptual resources – about bodies, environments, heredity and behaviour – that were available early on for an emerging mode of racial thinking, and how these developed in the context of European colonialism. The argument is that ideas about bodies, environments, heredity and behaviour were constantly intertwined in historically changing ways in this overall context and that it makes sense to grasp all these ways as ‘racial’, rather than confining the idea of race to, say, the Enlightenment and thereafter.

The period we explore in this chapter is a long and varied one: from the Enlightenment (dating from about 1650 to about 1800) to the era of eugenics (from the 1880s to the 1930s). The last chapter, although it started with the ancient and medieval periods, also explored early modern New World contexts, reaching into the late eighteenth century, and thus overlaps considerably with this chapter. But I want to keep this very broad period in mind, because it helps to grasp a series of transitions – but also continuities – which are vital to understanding changing ideas about race and changing structures of racialised relations.

As we saw in the previous chapter, some scholars speak of a transition from a pre-1800 classification of cultures to a post-1800 classification of bodies. I think this is misleading in so far as it ignores the role of ideas about bodies, nature, heredity and blood in earlier periods – although these ideas need to be understood in their historical context. It is also potentially misleading by inviting us to focus only on bodies (or more specifically biology) after 1800, neglecting the role of ideas about culture and behaviour, or rather neglecting how these might have been understood to shape biology, rather than biology determining culture in a one-way relation. As I have argued, race has always to be seen as a natural–cultural assemblage in which ‘nature’ and ‘culture’ are always shaping each other and the differences between them are not always clear.

However, there is no doubt that changes in racial thinking did take place, especially during the nineteenth century, although these have to be seen in the context of the longer period spanned by this chapter. By 1850 the Scottish medic and anatomist Robert Knox could say, ‘That race is everything, is simply a fact, the most remarkable, the most comprehensive, which philosophy has ever announced. Race is everything: literature, science, art – in a word, civilization depends on it’ (Knox 1850). This statement would not have been made in 1650, or even 1750. As I have argued in previous chapters, the absence of a declaration of this kind in these earlier periods should not be taken to mean that racial thinking did not exist then: it was not organised under the banner of ‘race’ as a coherent and elaborated theory (about biology), but it certainly existed.

We have come on a long and varied journey in this book, covering a long time span from the ancient Greeks and Chinese through to the twenty-first century, and drawing examples from many geographical locations, including India, Japan, Australia, the Americas, Africa and Europe. My aim has been to analyse what race is – or what we should take it to be analytically – and how it works by demonstrating the varied forms that thinking about race and racial difference can take, and the different ways racial exclusion and inclusion can operate. In conclusion, I summarise some key ideas by addressing two areas in the theorising of race: (a) what race is; and (b) how we can explain its presence and operation. I then explore some dimensions of race as a global phenomenon.

Theorising race

How have social scientists tried to explain race? In essence, once they had concluded that race was not a biological reality, and was a ‘social construction’, explaining it became a matter of relating racial categories and racial thinking to other social processes and ideas. As we saw in Chapter 1, central to these other factors have been coloniality (encompassing colonialism, African slavery and post-colonial power differences) and capitalism: race has widely been seen as driven by the politics and economics associated with these processes, past and present.

Although race has been theorised in relation to other social forces, many scholars have argued that race should not be ‘reduced’ to being a side-effect of these forces (see Chapters 4 and 6): as a set of ideas and practices embedded in social contexts, race can drive other processes as well as being driven by them (Omi and Winant 1986). As we have seen, race can indeed become a major force, with the power to, among other things, explain ‘everything’, as Robert Knox put it in 1850 (see Chapter 3); to create what Du Bois called ‘double consciousness’ (see Chapter 8); to produce radical forms of segregation, complete with an elaborate etiquette of behaviour and rights in the US South and South Africa (see Chapter 7); and to shape ideas about the nation, development and immigration (see Chapters 6 and 8).

I start by mapping out the basic conceptual territory of race, providing a guide to what kind of phenomena we, as anthropologists, and others are talking about when we use this term. This proves more complicated than we might have imagined, because race is a concept that has been used in varied ways at different times, in different places and by different people.

Before I start sketching out the territory associated with the concept, it is interesting to try a small experiment, to see what the term means to you.

Defining ‘race’

This exercise is best done collectively, in a classroom or seminar context, but you can also do it individually.

Write down a definition of ‘race’, in terms of what you understand by the concept. What does something have to be, or to have, for you to apply the word ‘race’ or ‘racial’ to it?

What about the word ‘racist’? Is this different and if so, how?

When I try this exercise with students in Britain, there is no consensus about these terms. Some people talk in terms of nationality and cultural background; some mention religion; others mention physical appearance, referring, when pushed, to skin colour and perhaps type of hair. Occasionally, people will mention ‘blood’ or parentage. Being ‘racist’ is usually said to mean discriminating against someone – excluding them, insulting them – on the basis of these characteristics.

Already we can see that the term race covers a broad area, including terms – such as culture, nationality and religion – that might be seen as conceptually different from race. When we look at contexts where race is part of a public, official discourse and we might expect clarity about what it means, this looseness of meaning is reaffirmed. For example, Britain's Race Relations Act (1976) says race in its name, but actually defines ‘racial grounds’ of discrimination as including ‘colour, race, nationality or ethnic or national origins’. Legislators were not trying to produce a coherent conceptual definition of race for the analytic purposes of social science, but their definition is indicative of the vagueness of the term. It also indicates a tendency to simply avoid a clear definition: ‘racial grounds’ includes ‘race’, which remains undefined, as if everyone already knows what it is.

If a key frame for understanding the reproduction of racial difference and racial inequality in Latin America was the idea of mixture, while for the United States and South Africa it was segregation and desegregation, then race in Europe is overshadowed by the theme of immigration. This does not mean that that immigration has been unimportant in Latin America or the United States – or that mixture and (de)segregation are not significant in Europe – but immigration has provided the dominant frame for recent ideas about race in Europe in a way that exceeds both other regions (Silverstein 2005 The idea that racialised minorities are, in one way or another, related to the image of ‘outsider’, and that the nations of Europe are, in a deep historical sense, ‘white’, has profound roots in the region. This is despite the fact that many countries have been linked into centuries-old transnational networks of colonialism and empire, which brought non-whites into their territories from an early date, and despite the fact that post-WWII immigrant communities have now given rise to third-generation offspring who are, in most instances, national citizens of the countries their grandparents migrated to. This said, to grasp race in Europe we need to extend our gaze beyond post-WWII immigration. In fact, ideas about race in Europe draw heavily on other, linked, histories, which create the context from which more recent immigrations take their meaning.

European histories of race

First, Western Europe has been the source of the colonial and imperial enterprises that were constitutive of modern racial formations. European thinkers and scientists were at the centre of the production of knowledge about human diversity and race, drawing on information derived above all from European colonies (see Chapters 2 and 3). Europe provided the colonists who conquered and settled the Americas as well as the colonial staff who administered and governed colonial possessions, but colonial Europeans and their colonially born descendants also circulated through Europe, and colonial soldiers, traders and administrators frequently returned there.

Latin America and especially Brazil have often been seen as the polar opposite of the United States and South Africa in terms of racial formation. In the past Brazil touted itself as a racial democracy compared to the image of the United States as a racial hell; today, despite recognition that Brazil has its own problems of racism, some Brazilians still see race-based affirmative action as a US model of racial policy that is unsuited to their national reality, as we saw in the previous chapter. There are important differences between Latin America, the United States and South Africa, but these should not obscure the fact that they are all variants of a similar history of colonial rule, racial oppression and nation building with racial hierarchy at the core. The key differences lie in the way legal racial segregation and clearly defined racial identities came to characterise the United States and South Africa, and the legacies of these two features during the processes of formal desegregation that have occurred in the United States after WWII and in post-apartheid South Africa. In Latin America both features, while not absent, have been less marked.

In this chapter I explore why racial segregation emerged in the United States, how it operated and its continuing legacies today. As in the last chapter, I use ethnographies of particular places to illustrate the processes at work. At the end I deal briefly with South Africa, using it as a counterpoint to the United States, in order to examine segregation and desegregation in a context in which the subordinate black class is a native majority, rather than a deracinated minority, and has taken the reins of power.

Changing US demographics

In Chapter 2, in comparing patterns of race mixture and racial classification in the colonial Americas, we saw that the United States, especially in the South, developed along comparatively segregationist lines, drawing increasingly clear boundaries between white, black and native American from the late eighteenth century onwards, with black and slave being almost coterminous categories – although less so in the North – and an increasing emphasis on including mixed-race people in the subordinate categories. Table 7.1 shows how the country looked by 1860, just before the Civil War.

In the last chapter we already entered the twentieth century, via eugenics and the continued influence of scientific racial typologies and social Darwinism on thinking about human diversity. This and the concern changes that began in the early decades of the century, took fuller shape from mid-century and are still with us today. In terms of the conventional chronology of race that guides the first half of this book, and which I am also trying to challenge and refine, this period witnesses a shift from ‘biology’ to ‘culture’. Briefly put, the powerful reliance on biology that characterised late nineteenth- and early twentieth-century thinking about race is generally said to be displaced, especially after WWII, by an emphasis on culture, often signalled by using the terms ‘ethnic group’ or ‘ethnicity’ (derived in the 1930s and 1940s from the older term ‘ethnic’, as alternatives to ‘race’). Some approaches describe the complete demise of race – specifically in Europe – as a discredited concept that has lost virtually all traction and been replaced by a ‘cultural fundamentalism’, in which groups are seen as fundamentally different by virtue of cultures that are deeply rooted and basically conflictive. This fundamentalism does not link cultures to racial biology, nor does it see some cultures as inferior and others as superior (Stolcke 1995My view is that this does not do justice to the ways race, racial thinking and racial hierarchy do persist, even in Europe.

Others do not envisage the erasure of race, but instead a complex shift, involving different but overlapping spheres – science, politics, everyday cultural practice – and hiding the persistence of race and of many racialised processes of naturalisation, not to mention the persistence of racism, now apparently without the trappings of race or biology. This scenario, in which race is ‘buried alive’ (Duster 2003;Goldberg 2008), has been said to involve ‘neo-racism’ (Balibar 1991a), ‘new racism’ (Winant 2002), ‘cultural racism’ (Hale 2006: 144; Taguieff 1990) and even ‘raceless racism’ (Goldberg 2008). Scholars have also referred to ‘colour-blind racism’ (Bonilla-Silva 2003) and ‘race-evasive discourse’ (Frankenberg 1993), to indicate the ways many people in the United States, especially white people, try to avoid explicit reference to race, amid claims that we live in ‘post-racial’ times (Lentin 2014).

Introduction

In the preceding chapter we explored how the concept of race as a biological reality has persisted in a number of ways in the spheres of biological science, psychology, medicine and forensics. In this chapter I look at how race as a concept and racialised ideas about nature and biology appear (and disappear) in the domains of politics and the everyday. This is potentially a vast topic, and more detail about it will emerge in subsequent chapters that explore how race operates in the social and political life of specific regional contexts. What I am interested in in this chapter is seeing how a more or less explicit reference to ‘race’ remains part of public institutional practice in an era of cultural discourse and how a concern with race as phenomenon involving biology, heredity and nature – not just culture – also persists in the public and everyday domains.

Of science and society

A caveat: the fact of discussing first ‘science’ and then ‘politics and the everyday’ should not be taken to imply a separation between science and society, because science is itself a social activity and is deeply implicated in social policy. The findings of science about race and medicine have vital practical and policy implications (e.g. about how best to practise diagnosis, how to design screening programmes, how to address public health problems such as heart disease or hypertension), as well as shaping the economic workings of pharmaceutical companies which may choose to target ‘ethnic’ minorities with specific treatments. What genomics has to say about human diversity and race in forensics has important consequences for policing, the collection and storing of DNA in databases and the possible targeting of racial minorities in the criminal justice system. If we were to believe the race and IQ theorists, this would have radical consequences for education policy.

More broadly, science is deeply embedded in a social context, even while its internal problem-solving is not determined by this context: as we saw in the last chapter, it is hard to draw very tight connections between specific racial theories in late nineteenth-century science and specific configurations of empire; likewise, the demise of scientific racism started while European empires were still at their peak.