Talk:Operational Requirement F.155

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I am curious about several parts of this this statement:

The English Electric Lightning for point defence was nearing completion of development.

Was it not the case that the Lightning was considered as an outright replacement for the Javelin? IE, was there always a plan to introduce the SR.177 beside the Lightning, or was this a plan that developed while the various plans were under design?

The Saunders-Roe SR.177 mixed-power was planned to enter service in a few years and cover the interim period.

Which interim? Between the Javelin and F.155?

The Canadian Avro Arrow was a possible contender to cover the interim but its capability was for an intruder at 50,000 ft travelling a Mach 0.9.

The Arrow was certainly more capable than that, with supercruise of M1.5 at 50kft and ceilings considerable higher. This statement seems rather suspect. From all the documents I can find (on the web), it was pretty much a direct match for the F.155 in overall performance and range. Does anyone have more detail?

Maury 21:51, 7 December 2006 (UTC)

British Secret Projects: Jet Fighters Since 1950 by Tony Buttler. I should have added it as a reference. Will do so now and be more explicit on SR.177. GraemeLeggett 09:56, 8 December 2006 (UTC)

Would you mind copying in some of the text on the Arrow? Like I said, these numbers appear incorrect. My question is whether this is a case of deliberate underestimation in order to make the British designs look better in comparison (as happened with the Arrow, they "tuned" the requirements to make sure Avro won), or they knew something everyone else didn't. Maury 12:58, 8 December 2006 (UTC)

The Derek Wood book, Project Cancelled also deals with the SR.177 proposals. Do you know it? Bzuk 13:02, 8 December 2006 (UTC)

The sole purpose behind the development of the mixed-power SR.177 (and the preceding SR.53) was to achieve the extremely high climb rates necessary for interception of possible future Soviet high-altitude supersonic bomber designs, which, due to their supersonic speed, would give very little warning time in which to 'scramble' the defending fighters once detected by the then-contemporary ROTOR system. As it turned out, the Soviets didn't deploy a supersonic bomber with the range to reach Britain until much later, and in the event, the Lightning's climb performance was deemed more than adequate. This need for an excellent climb performance was the reason for the Napier Scorpion boost rocket motor in the ventral fuel tank of the P.1 (Lightning) being developed as a sort of insurance. Again, as it turned out, it wasn't needed. So the SR.177 was cancelled (apart from any other reasons) because the Lightning was thought capable of doing the job just as well. The same applied to F.155. In addition, a Mach 3 interceptor version of the TSR.2 was also planned, but that too was cancelled.

BTW, the term 'point defence' isn't really accurate, it was the time available to intercept that mattered - if you double the speed of the intruder you halve the time available to the defenders to intercept it. And any UK interceptions of Soviet bombers would have taken place while the bombers were still out over the North Sea. — Preceding unsigned comment added by 80.4.57.101 (talk) 14:02, 17 February 2012 (UTC)

Assessment comment

The comment(s) below were originally left at Talk:Operational Requirement F.155/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

Needs a good editor to rewrite it. Karl Dickman talk 22:42, 21 January 2007 (UTC)

Last edited at 22:42, 21 January 2007 (UTC). Substituted at 01:54, 30 April 2016 (UTC)

OR F.155 vs. OR.329

In many other articles on the topic, the term "OR.329" is used to describe what I think is the same set of designs. Does anyone know more on this? It isn't mentioned here at all. Maury Markowitz (talk) 16:26, 4 June 2020 (UTC)

OR.329 was the Operational Requirement - F.155T was the specification issued to the aircraft manufacturers to meet that requirement - the article appears to be incorrectly named as F.155 wasn't the Operation Requirement.Nigel Ish (talk) 19:14, 4 December 2021 (UTC)