Bugatti's U16

Author

admin

Browse pages
Current page

1

Current page

2

Current page

3

Current page

4

Current page

5

Current page

6

Current page

7

Current page

8

Current page

9

Current page

10

Current page

11

Current page

12

Current page

13

Current page

14

Current page

15

Current page

16

Current page

17

Current page

18

Current page

19

Current page

20

Current page

21

Current page

22

Current page

23

Current page

24

Current page

25

Current page

26

Current page

27

Current page

28

Current page

29

Current page

30

Current page

31

Current page

32

Current page

33

Current page

34

Current page

35

Current page

36

Current page

37

Current page

38

Current page

39

Current page

40

Current page

41

Current page

42

Current page

43

Current page

44

Current page

45

Current page

46

Current page

47

Current page

48

Current page

49

Current page

50

Current page

51

Current page

52

Current page

53

Current page

54

Current page

55

Current page

56

Current page

57

Current page

58

Current page

59

Current page

60

Current page

61

Current page

62

Current page

63

Current page

64

Current page

65

Current page

66

Current page

67

Current page

68

Current page

69

Current page

70

Current page

71

Current page

72

Current page

73

Current page

74

Current page

75

Current page

76

Current page

77

Current page

78

Current page

79

Current page

80

Current page

81

Current page

82

Current page

83

Current page

84

Current page

85

Current page

86

Current page

87

Current page

88

Current page

89

Current page

90

Current page

91

Current page

92

Current page

93

Current page

94

Current page

95

Current page

96

Current page

97

Current page

98

Current page

99

Current page

100

Current page

101

Current page

102

Current page

103

Current page

104

Current page

105

Current page

106

Current page

107

Current page

108

Current page

109

Current page

110

Current page

111

Current page

112

Current page

113

Current page

114

Current page

115

Current page

116

Current page

117

Current page

118

Current page

119

Current page

120

Current page

121

Current page

122

Current page

123

Current page

124

Current page

125

Current page

126

Current page

127

Current page

128

Current page

129

Current page

130

Sir,

You are wrong to suggest (Motor Sport, April 1988) that the 16-cylinder Bugatti engine was cobbled together out of old bits. The T45 was a completely new design, with more in common with the T46 and T50 than the T35 or T39, despite retaining the three-valve head.

The entire Bugatti Empire seems to have been built on the sale of the original U16 Aero-engine to the Americans during the First World War. However, Bugatti had not finished building it and clearly wanted another go with a racing engine; which he did in 1929-30.

The engineering justification for small cylinders is to allow a higher compression-ratio and specific output without getting excessively high valve and plug temperatures. Plugs were very unreliable in those days and compression ratios accordingly low.

The U16 layout with two crankshafts gives a short, compact and light design with low frontal area, and it fits into a standard-width chassis. A V16 would not have been easy to design with such close-spaced bores.

The crankshafts bolt onto the bottom of the cylinder blocks. Main bearings are spring rollers and the big ends are white metal. A plain centre main gives oil access, and there are blow-off valves at either end of the crankshafts. The two blocks are keyed onto the end gear casing which contains 15 gears. The blowers are driven off the back. The gears on the back of the cranks are centilevered, there being no outboard bearing to steady them. The whole thing is a beautifully compact unit.

The Bugatti’s engines run backwards so that the transmission could go round in the conventional way. The Maserati U16 had engines going round the conventional way, with the transmission going backwards.

This was because the Maserati engine was made from near-standard bits. The remarks about the Maserati being too fast for the chassis could be because this backwards rotation causes abrupt break-away if you lift your foot going too fast round a right-hand bend. It is possible that the later 5-litre Maserati U16 was changed to left-hand rotation because at least one engine was built to run backwards.

When Ernesto Maserati was asked about his U16 engines, he said that he was copying the Bugatti concept. It must, I think, be assumed that all the engine makers had been watching the development with interest, although very few had established eight-cylinder designs running from which to develop their own.

Bugatti probably built six engines, since he usually made half-dozens. He probably blew one up on the test bed and he also destroyed one in a car, leaving four. Ernesto Maserati said that he made three U16 cars, four V4 of 4-Litres (one of which was a sports-car for pulling the birds) and one V5 5-litre car.

The two racing cars have disappeared, but two V5 engines survive from a boat, one left-hand and one right-hand rotation. Perhaps they come from a car, because the Maseratis put two U16s into a chassis making a 32-cylinder car. They seem to have frightened themselves with the project because it was hurriedly and completely dismantled. Perhaps it was the end of the V5 racer.

If Rolls really wants something exclusive, what about a 24- or 32-cylinder motor?

J Howell

Copthorne, Sussex