Apparently Spey on Mirage III too.
In a footnote, he mentions that the Spey-engined Mirage IIIK was proposed to the RAF as a Hunter replacement in 1964, "with the full backing of Rolls Royce": sounds to me like another round of RR's anything-to-undermine-the-Harrier campaign to me... :rolleyes: He confirms that the Spey-Mirage did NOT need a larger fuselage, since the Spey had a smaller diameter than both the Atar and the Avon, although he doesn't mention the issues of air intake mass-flow and rear fuselage cooling. The latter was the reason for the Kfir's enlarged rear fuselage BTW: the J-79 is actually narrower than the Atar. With the Spey being a turbofan, I'd imagine that the duct wall temperature between the core and the afterburner would be lower than the J-79, although it might well have needed a Kfir-style fintake for afterburner cooling.
http://www.whatifmodelers.com/index.php ... 54.40;wap2
(also a mention on Wiki article on Mirage III)
Maybe these are not the best sources, but some they are.
(But I'm not an expert on that, so maybe I'm wrong)
Yep, the Spey-engined Mirage IIIK and IVK were the ones I was after, mainly. With the Avon M.III being a nice plus. I'm building an AU nation, slowly, and atm quite a few of the mid-CW aircraft might just be Spey powered, for commonality, fuel efficiency and the habit of flying low over the Northern Atlantic regions. Although I've also heard nice things about the Atar maintenance and handling qualities...
There were also talks about Spey-engined F-100 Super Sabre, A-4 Skyhawk and F-8 Crusader, to mention a few. And of course, the Phantom and A-7 got the things anyways. More projects here:
http://www.secretprojects.co.uk/forum/i ... 471.0.html
And for the Mirage IVK:
http://www.secretprojects.co.uk/forum/i ... 299.0.html