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Zoo Tycoon said:
“Does anyone know if the J85 has steel LP compressor blades/staters?

I notice it was never used in any super cruise applications and typically super cruise engines will have a steel front end. This was/is because of the heat build up during sustained supersonic flight. Aluminium Alloy loses strength too quickly and Titanium has a habit of catching fire although has seen a few applications. Most supersonic aircraft such as the F5 will only be cleared for a short time at high speed measured in tens of seconds to a few single minutes. The XB1 usefulness will be significantly limited if it can’t collect sustained supersonic flight thermal flux data.

Also has anyone seen objective for time at supersonic Mach number?
Nobody has had issues with titanium fires in their engines since the 1960s, because people learned just how much stretch was happening and made the appropriate allowances for it.”

Scott Kenny replied;-
Nobody has had issues with titanium fires in their engines since the 1960s, because people learned just how much stretch was happening and made the appropriate allowances for it.

Zoo Tycoon
Ah no, Concorde entered service in 1976, and by 1980 had suffered two Ti compressor fires. So several Ti compressor stages were changed to steel. I understand the problem wasn’t blade stretch, but manufacture quality assurance. Remember that in the first five years of Concorde service the fleet, although small, achieved about 100 x the time at Mach 2 as the entire military previous experience. The grim reality associated with pioneering is a harsh mistress.

<blockquote data-quote="Zoo Tycoon" data-source="post: 614019" data-attributes="member: 1642">Zoo Tycoon said:“Does anyone know if the J85 has steel LP compressor blades/staters?I notice it was never used in any super cruise applications and typically super cruise engines will have a steel front end. This was/is because of the heat build up during sustained supersonic flight. Aluminium Alloy loses strength too quickly and Titanium has a habit of catching fire although has seen a few applications. Most supersonic aircraft such as the F5 will only be cleared for a short time at high speed measured in tens of seconds to a few single minutes. The XB1 usefulness will be significantly limited if it can’t collect sustained supersonic flight thermal flux data.Also has anyone seen objective for time at supersonic Mach number?Nobody has had issues with titanium fires in their engines since the 1960s, because people learned just how much stretch was happening and made the appropriate allowances for it.”Scott Kenny replied;- Nobody has had issues with titanium fires in their engines since the 1960s, because people learned just how much stretch was happening and made the appropriate allowances for it.Zoo Tycoon Ah no, Concorde entered service in 1976, and by 1980 had suffered two Ti compressor fires. So several Ti compressor stages were changed to steel. I understand the problem wasn’t blade stretch, but manufacture quality assurance. Remember that in the first five years of Concorde service the fleet, although small, achieved about 100 x the time at Mach 2 as the entire military previous experience. The grim reality associated with pioneering is a harsh mistress.</blockquote>

[QUOTE="Zoo Tycoon, post: 614019, member: 1642"] Zoo Tycoon said: “Does anyone know if the J85 has steel LP compressor blades/staters? I notice it was never used in any super cruise applications and typically super cruise engines will have a steel front end. This was/is because of the heat build up during sustained supersonic flight. Aluminium Alloy loses strength too quickly and Titanium has a habit of catching fire although has seen a few applications. Most supersonic aircraft such as the F5 will only be cleared for a short time at high speed measured in tens of seconds to a few single minutes. The XB1 usefulness will be significantly limited if it can’t collect sustained supersonic flight thermal flux data. Also has anyone seen objective for time at supersonic Mach number? Nobody has had issues with titanium fires in their engines since the 1960s, because people learned just how much stretch was happening and made the appropriate allowances for it.” Scott Kenny replied;- Nobody has had issues with titanium fires in their engines since the 1960s, because people learned just how much stretch was happening and made the appropriate allowances for it. Zoo Tycoon Ah no, Concorde entered service in 1976, and by 1980 had suffered two Ti compressor fires. So several Ti compressor stages were changed to steel. I understand the problem wasn’t blade stretch, but manufacture quality assurance. Remember that in the first five years of Concorde service the fleet, although small, achieved about 100 x the time at Mach 2 as the entire military previous experience. The grim reality associated with pioneering is a harsh mistress. [/QUOTE]

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