getting to grips with aircraft performance 如何掌握飞机性能 2(15)

.  
At a fixed cruise Mach number, the maximum FL (buffet ceiling) is determined for n = 1.3g.

3.4. Cruise Optimization: Step Climb
Ideal cruise should coincide with optimum altitude. As a general rule, this altitude is not constant, but increases as weight decreases during cruise. On the other hand, ATC restrictions require level flight cruise. Aircraft must fly by segments of constant altitude which must be as close as possible to the optimum altitude.
In accordance with the separation of aircraft between flight levels, the level segments are established at ± 2,000 feet from the optimum altitude. In general, it is observed that in such conditions:
SR ≥ 99% SR max
As a result, the following profile is obtained for a step climb cruise (Figure F26).

thrust

Flight levels are selected in accordance with temperature conditions. Usually, the first step is such that it starts at the first usable flight level, compatible with maximum cruise altitude. This is the case with the ISA condition cruise example in Figure F26.
4. FCOM CRUISE TABLE
In the FCOM, cruise tables are established for several Mach numbers in different ISA conditions with normal air conditioning and anti-icing off. Aircraft performance levels are presented in Figure F27.

 IN FLIGHT PERFORMANCE CRUISE  3.05.15  P 9 
SEQ 110  REV 31 

R
CRUISE -M.78 
MAX. CRUISE THRUST LIMITS NORMAL AIR CONDITIONING ANTI-ICING OFF  ISA CG=33.0%  N1 (%) MACH KG/H/ENG IAS (KT) NM/1000KG TAS (KT) 
WEIGHT (1000KG)  FL290  FL310  FL330  FL350  FL370  FL390 
50  84.0 .780 1276 302 180.9 462  84.0 .780 1189 289 192.5 458  84.0 .780 1112 277 204.0 454  84.1 .780 1044 264 215.4 450  84.7 .780 992 252 225.6 447  85.9 .780 955 241 234.1 447 
52  84.2 .780 1288 302 179.2 462  84.2 .780 1202 289 190.3 458  84.3 .780 1127 277 201.4 454  84.5 .780 1060 264 212.0 450  85.1 .780 1011 252 221.3 447  86.3 .780 977 241 229.0 447 
54  84.4 .780 1300 302 177.5 462  84.5 .780 1216 289 188.1 458  84.6 .780 1142 277 198.6 454  84.8 .780 1079 264 208.4 450  85.5 .780 1031 252 217.0 447  86.9 .780 1003 241 223.1 447 
56  84.7 .780 1314 302 175.7 462  84.8 .780 1231 289 185.9 458  84.9 .780 1159 277 195.7 454  85.2 .780 1097 264 204.8 450  85.9 .780 1052 252 212.6 447  87.6 .780 1036 241 216.0 447 
58  84.9 .780 1328 302 173.9 462  85.1 .780 1246 289 183.6 458  85.2 .780 1176 277 192.8 454  85.6 .780 1117 264 201.3 450  86.4 .780 1075 252 208.1 447  88.3 .780 1070 241 209.0 447 
60  85.2 .780 1342 302 172.0 462  85.3 .780 1262 289 181.3 458  85.6 .780 1195 277 189.8 454  85.9 .780 1137 264 197.6 450  86.9 .780 1102 252 203.0 447  89.2 .780 1110 241 201.5 447 
　
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：getting to grips with aircraft performance 如何掌握飞机性能 2(15)