Quality and Cost Control

Quality and Cost Control for the UltimateL39

The original path to fabricating parts for the UltimateL39 project involved an English Wheel and a Shrinker/Stretcher to produce fan duct 1/4 panels. These would then be welded together into an assembly and strengthened with supporting banding sections riveted onto the outer duct assembly. It took two weeks to generate the first 1/4 panel and thus it was obvious that two aircraft conversions were out of the question. In addition, cold working aluminum panels then welding them together (which anneals the aluminum at the weld seam) invites stress fatigue cracking shortly after putting the assembly in service. Major OEMs address this by using stamped sections and riveting them together (like the WestWind fan duct). When weldments are done, the final assembly is heat treated to relieve local stress and generate uniform strength. Stamping tooling was cost prohibitive and heat treating an assembly as large as a fan duct is an invitation to generate very large pretzels. We needed a solution that could give us the exact complex fan duct and inlet cone geometry we needed to extract exceptional performance from the install yet straight forward enough to be repeatable and cost effective.

The production solution was a carbon composite fan duct and inlet cone. This is nothing new as Honeywell does this on the -20, -40,, variants of the TFE731 series of motors. Tooling for large composite parts is not cheap but within the realm of possibility on this project: this is especially true when you look at ten weeks of a craftsman's labor to generate even one fan duct by working aluminum. Molds were made and casting tooling was generated for the 410 Stainless Steel front motor mounts. It was a lot of work and relatively expensive to get here but now a -3 motor installation kit can be generated in a reasonable amount of time with a high level of quality on an ongoing or repetitive basis. Up front costs were high but, in addition to repetitive quality, production costs are relatively low. Installations and engine installation kits from other vendors are costly while the UltimateL39solution is significantly less. So this is the answer when I'm asked "If your solution is soooo good, why does it cost less money?". Because we designed it that way.