Originally Posted by
RichardLee
Helix bikes are welded inside an inert vacuum chamber to mitigate problems working with titanium. What is puzzling though is there cannot possibly be inert vacuum chambers large enough to accommodate anything the size of $100M+ fighter jet aircraft.That means either (a) inert vacuum chambers are not really necessary to effectively work with titanium, or (b) the most sophisticated fighter jets have structural integrity problems. Neither observations are consistent with all the type about sub-sonic titanium bicycles.
Nearly 6 am Jan 1...awggh... exhausted but just can't fall asleep.
Titanium isn't generally used for big stuff like the airframe or skin...at least on no plane I ever worked on. (Back in the day, it was all aluminum.) TI is typically used for higher temp applications, eg, jet engine exhaust flow control, where individual parts aren't large.
(TI is used more extensively in the SR-71, which had friction heated wings at mach 3 speeds. Many assemblies were loose at room temperature cuz operating dimensions were only achieved at much higher in-flight temps. But one can make big things with rivets, which can make very strong assemblies. And gas shielded welding works better with simply shaped parts.)