Lancair Legacy - CAFE Foundation

165016001550150014501400Legacy N199L: EGT and CHT spreads at 8,500', 2550 RPMA⊕A⊕A⊕â200ââ190â1350â 18017514 14.5 15 15.5 16 16.5Fuel flow, gallons per hour (gph)Legacy N199L; wide open throttle, CAFE data 2/23/02. CHT for 100 °F day.Cont. IO-550-N engine, 310 HP. V = speed at best CAFE fuel flow.bCEGT #1EGT #2V bCEGT #3⊕ EGT #5= 282.4 smph @ 14.2 gphA⊕CHT #1CHT #2CHT #3AâA⊕CHT #5TAS390380370360350340330320310300290280270260250240230220210MPG x108.5K/2550: This graph depicts the veryhigh cruise speeds that the Legacy canachieve at 8,500’ density altitude. Due toconcerns about leaning the mixture at relativelyhigh power settings, the range of fuelflows examined here is more limited.Nevertheless, it is evident that the tests didexplore lean of peak mixture settings whichyielded some reduction in CHT in all cylinders.The engine ran smoothly at all settingspresented here.The CHT values here show that theLegacy cooling system is more than adequateat the high cruise speeds at which itnormally operates. The high level of ramair pressure available at such speedsaffords such fast aircraft a substantial coolingadvantage. However, an ineff i i c i e n tcooling system at such high pressures cancause large speed penalties that go unnoticedunless the system is critically examined.The Legacy’s cooling system was testedin both climb and cruise mode to determineits ram recovery. We define ram recoveryas that percentage of freestream total pressurethat is ‘captured’in the cold air coolingplenum inside the cowling. The measurementwas made using a pair of probesinside the cold air plenum. One probe wasa piccolo tube that sampled average staticpressure in the plenum. The other probewas a forward facing pitot tube placed justabove cylinder #3’s cooling fins inside thecowl.The test results showed that the Legacyachieves 60% ram recovery in cruise at240 KCAS but 117% ram recovery in climbat 138 KCAS . The readings of the piccoloand pitot were essentially identical incruise. In climb, the piccolo read 12.4 inchesof water versus 14.2 on the pitot probe.14 MONTH 2002