Tuesday, June 4, 2013

737 Increases use of Titanium on Its Engine.

Back in the day, a long time ago, my uncle pioneered with Titanium, at Lockheed Skunkworks when developing the SR-71.  He recounted to me, "they had no manual on forging Titanium panels, and attaching it to the airframe. Many years later after his career on the SR-71 became history, I went to a aero space museum in California to see one of these birds that he had help design, make, and fly. I didn't kick the tires, but I slapped the titanium hull shaped like a hydroplane hull. It sounded like a cardboard box that couldn't hold the pressures, heat and power of a Mach 3+ aircraft.  A revolution had arrived and then it faded as it aged. But the technology born out on scraps of papers, and trial and error, remained into the space age. Titanium has become the metal of choice in commercial aviation. So without further waxing on about the SR-71 lets talk about the MAX.

But First a Salute To The Titanium Bird


So the Max takes on advancements from the SR-71 with new titanium engines aspects.

More Details on 737 Max Materials Emerge   "Article reference link"


"A switch from composite to titanium for the inner walls of the thrust reversers on the Boeing 737 Max has allowed designers to increase the fan diameter in the airplane’s CFM International Leap-1B turbofans without a proportional increase in the size of the nacelle. The relatively minimal growth of the nacelle means Boeing could keep its original plans for coping with the small amount of ground clearance margin available while optimizing thrust levels, explained 737 Max program vice president and general manager Keith Leverkuhn."

So the the old 737 CFM engine is not your dads CFM engine. Its a pouring out of technology on the 737 Max structure and engines. The horses aren't spared in this effort to Maximize the MAX.

“We tailored the engine to the wing [and] we tailored the engine to the thrust that we need to be able to deliver the combination of fuel burn and range,” said Leverkuhn, who took over as Max program head for Bob Feldman some two months ago, when Feldman moved to the 777X.

Another recent advance involved what Leverkuhn described as a “sculpting” of the engine inlet to maximize laminar flow. Those and other refinements allowed Boeing to raise the target range of the 737 Max 8 some 500 nm beyond that of the 737-800, to 3,620 nm, as well as meet Chapter 14 noise requirements. It also now expects the fuel-burn advantage to reach 13 percent. Previous estimates placed the benefit at 11 percent. “And I would say there is pressure for even more as we learn more and more about the engine and more about the airplane,” said Leverkuhn."

So Boeing is in the sweet spot to substantially challenge the head started Neo.  Whose designs are pretty much set in cement. The following considerations from the article tell out what advantages the Titanium influence will have on performance, maintenance and efficiency. The Max with a 13% fuel burn improvement doesn't just stop engine improvement. Combine this configuration with wing and body improvement. A 13% improved engine is then mounted on an optimized body, where Boeing has been playing with for over forty years. The have the 737 aero science down to the rivets. Stuff this aircraft with lightweight optimization and you get an over achiever on maintenance, consumption and comfort. The final erasure and sketch is about here so it can freeze and build.

SR-71 engine like stuff:
  • Another recent advance involved what Leverkuhn described as a “sculpting” of the engine inlet to maximize laminar flow. Those and other refinements allowed Boeing to raise the target range of the 737 Max 8 some 500 nm beyond that of the 737-800, to 3,620 nm, as well as meet Chapter 14 noise requirements. It also now expects the fuel-burn advantage to reach 13 percent. Previous estimates placed the benefit at 11 percent. “And I would say there is pressure for even more as we learn more and more about the engine and more about the airplane,” said Leverkuhn.
  • Although titanium weighs somewhat more than the composite material typically used for the inner wall, the need for insulation blankets to protect the composite from the heat generated means the traditional combination weighs more, explained Leverkuhn.
  • The titanium option will also result in less maintenance, he added, particularly given the increased heat exposure resulting from drawing the inner wall closer to the engine to minimize the size of the nacelle.
  • “A titanium inner wall is unique in the industry,” said Leverkuhn. “However, we've had some experience with it in military applications, so we've taken some lessons learned from them and bring that technology forward on the Max.”
  • Now scheduled to reach firm configuration in July, the program has already passed through the midpoint of its so-called long-lead releases as part of the detailed design process, added Leverkuhn. In short, although the program remains still relatively early in the development process, all evidence presented by Boeing appears to indicate a clear path toward certification and entry into service as planned, in the fourth quarter of 2017.