I've now collated the dba flyby measurements taken by ELS as each craft crossed the finish line at the recent Rother Valley National. The line was on a full power part of the course so the figures are a good guide, however the line was wide and on occasion craft took the corner wide and closer to the meter so some individual readings may be high. The average is probably the most reliable guide.



The limit is 96dba so obviously those with averages over that need to be working on the problem, particularly the top 3. From noise analysis so far silencers are the key problem. As well as ensuring any stuffing is up to scratch, in some cases bigger and better silencers are needed. You may also want to consider turning the exhaust into the plenum, although that brings it's own problems. Running the fan above 150m/sec tip speed also seems to generate excess noise.



no average loudest

39 99.5 105

5 99.2 106

33 98.3 103

316 97.7 102

2 97.4 102

16 97.4 103

50 97.3 100

34 96.7 103

32 96.6 102

1 96.3 101

37 94.9 101

42 94.5 98

110 93.4 95

144 92.8 98

76 92.6 94

83 92.6 98

100 92.6 95

160 92.5 93

55 92.2 104

52 92.1 94

140 92.1 98

70 92 98

54 91.8 97

150 91.7 99

88 91.6 94

36 91 96

169 91 98

53 90.9 97

78 90.8 95

194 90.7 98

J20 90.4 94

81 90.3 92

46 90.2 96

18 89.8 92

40 89.6 94

87 89.6 95

J19 89.6 92

145 89.4 98

118 89.3 96

72 88.9 95

117 88.3 93

133 88 97

191 87.1 92

201 83.5 96

J11 82.5 89