xrearl Posted January 11, 2017 Posted January 11, 2017 https://tacairnet.com/2015/06/18/redeveloping-the-f-4-phantom-ii-into-a-mach-3-fighterspy-plane/ 3 Quote
RUSTYMORLEY Posted January 11, 2017 Posted January 11, 2017 Wow. Thanks for sharing this. Same for me, a very unusual tale indeed !!! Quote
JediMaster Posted January 13, 2017 Posted January 13, 2017 I remember reading that in one of my books about the F-4. As it never got very far it's not widely known, but it's an interesting "what if" up there with the F-108, TSR2, and YF-12. Quote
Stratos Posted January 14, 2017 Posted January 14, 2017 I just printed it and will add to my Phantom reference book, such development planes are always cool. Quote
Toryu Posted January 16, 2017 Posted January 16, 2017 You can't build a Mach 3 capable airframe by just bolting on water-tankss, tweaking the inlet-system and modifying the flight-controls of a Mach 2 airframe. The most critical problem north of Mach 2 is shock-heating. You can go Mach 2.5 for a very short time in an aluminium-airframe (as actually demonstrated by F-4s during Project Skyburner), but that's about it. Aluminium will weaken a lot above 120°C, which is about the leading-edge temperature at Mach 2*. If you want to go faster (even just on a dash), you'll need different materials: stainless steel (heavy) or titanium (a dog to work with - especially machining - thus gold-dust expensive). The US had their strategic bird at this time (SR-71), and giving funds to Israel for tweaking a Mach 2 bird into a low-volume Mach 3 retrofit-program wasn't a politically and fiscally sane idea. ___ * Depends on a couple of factors, but generally Mach 2 is an upper-bound for aluminium-airframes for this very reason 2 Quote
Fubar512 Posted January 17, 2017 Posted January 17, 2017 You can't build a Mach 3 capable airframe by just bolting on water-tankss, tweaking the inlet-system and modifying the flight-controls of a Mach 2 airframe. The most critical problem north of Mach 2 is shock-heating. You can go Mach 2.5 for a very short time in an aluminium-airframe (as actually demonstrated by F-4s during Project Skyburner), but that's about it. Aluminium will weaken a lot above 120°C, which is about the leading-edge temperature at Mach 2*. The F-104's Vmax was also limited due to thermal issues, it could attain a Mach number high enough to melt its windscreen (which if I recall correctly, occurred between Mach 2.25 and 2.5). I am sure a similar issue existed with the F-4. Quote
Toryu Posted January 17, 2017 Posted January 17, 2017 There was a flight by an operational F-104C, using tweaked inlet-cones (similar to those on the NF-104) and the larger tail of the twin-seaters/ G-model. They went out to about Mach 2.5 with acceleration still ongoing, when the pilot (Tom Delashaw) RTBed. http://www.i-f-s.nl/f-104-records/ There used to be a pilot's account of Delashaw, but I can't find it now. The F-104G has three limits concerning speed: M 2.0 (mainly a stability limit) 750 KIAS (q-limit) 121°C Compressor Inlet Temperature The windscreen-thing was probably an issue on all fightes back then. Luckily, the fuel wouldn't last too long anyway. Quote
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