N930NN, one of American’s 304 Boeing 737-800s, taxies in to the terminal at DFW. ⠀ ⠀ Fitting the 60-inch fan CFM56-3 to the 737-300/400/500 required some creativity with the low wings and squat undercarriage of the 737; the engine accessory drives were mounted to the sides allowing the nacelle to be flat bottomed. The top of the nacelle is nearly level with the top of the wing and the engine is tilted 5 degrees nose up for intake clearance which also gives a downward thrust component. ⠀ ⠀ On the 737NG family, the landing gear was lengthened to allow stretched fuselage versions, but this also allowed a new CFM56 version, the -7, to be used which has a 61-inch fan. The intakes for the NG are rounder and less flat bottomed than those of the 737-300 family as a result.⠀ ⠀ The CFM56-7B on the Boeing 737NG family was a significant improvement over the CFM56-3 engine used on the 737 Classics in many ways to create a more efficient, powerful and reliable engine.⠀ ⠀ For example, aerodynamic improvements mean the number of fan blades were reduced from 38 on the -3 to only 22 on the -7B. In addition, advances in software and materials science also offer an 8% reduction in fuel burn and a 15% reduction in maintenance costs on the CFM56-7B versus the older CFM56-3. Compared to the older -3, the -7B engines can stay on the wing about 20% longer before major maintenance is needed. ⠀ ⠀ Commercial aircraft engines are some of the most fascinating technical achievements in aviation in their own right.⠀ ⠀ #Avgeek #aviation #aircraft #planeporn #KDFW #DFW #airport #igTexas #planespotting #airlines #Boeing #737 #American #AmericanAirlines #dfwavgeek #instagramaviation #N930NN #splendid_transport #instaaviation #aviationlovers #aviationphotography #flight #aviationphotography #AvgeekSchoolofKnowledge #AvGeeksAero #AvGeekNation⠀ (at DFW Airport) https://www.instagram.com/p/B5G_wEehKcz/?igshid=s1lao42hhxhz