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By: - 4th May 2012 at 15:29 Permalink - Edited 1st January 1970 at 01:00
Don't know if this helps, but!
There were two flavours of AI23.
Only AI23B had a scope, the earlier AI23 used a HUD.
So Mk1 and 2 variants used AI23 (oddly never remember it being called 23A) and were never fitted with AI23B and could therefore only be fitted with the Firestreak, which if I remember correctly was originally called Blue Jay or something very similar.
The AI23B version was introduced with the F3 onwards. Although of course one of the major enhancements to the B version was the ability to interface with Red Top (this at one time also had a Blue name) missiles which was served by the "Computer Red" itself a part of the radar. Oddly the HUD disapeared in favour of a heads down scope.
Export and other variants had other colour designations for the analogue computer within the radar.
It is a common myth that AI23B could only ever operate in lockon mode, later mods ( and a change of designation to AI23C) allowed a "track while scan" pseudo mode. A change to the PRF rate also allowed the range to be increased to 80nm. You will often see references to its short range i.e. 30 milles but I've locked on airborne targets, at its then max range, of 60nm and we could still detect second timebase returns.
By: - 5th May 2012 at 01:12 Permalink - Edited 1st January 1970 at 01:00
[QUOTE=Peter Mills;1886075]Don't know if this helps, but!
Only AI23B had a scope, the earlier AI23 used a HUD.
QUOTE]
Peter,
I thought all marks of Lightning werre fitted with a radar scope?, early marks had the PAS fittment where as that latter had the LFS, none to my mind ever had an HUD fitted?
crl848,
It will be most likely that the radar system was removed or disabled prior to the testing the Mr Aird as aerodynamic test round would not require any 'lock' to function, De-Haviland would have used aircraft with a full radfar fitment to fully test live firing on drone targets.
Lets not forget that the DB aircraft were hacks used for lots of development in their specific field and many changes were made to there instruments and fits to suit their designated test programme.
The DB cockpit on p.31 is undergoing such mods and has its radar scope removed at the time of the picture being taken.
Regards,
John.
By: - 5th May 2012 at 09:24 Permalink - Edited 1st January 1970 at 01:00
Thanks, that sounds like the most likely explanation.
By: - 5th May 2012 at 13:12 Permalink - Edited 1st January 1970 at 01:00
I believe that one difference between AI.23 and AI.23B was that in the former the pilot used the CRT to acquire the target and then switched to the PAS (which provided steering and range marks) for the final attack. There were a number of criticisms of the PAS, and also of the need for the pilot to change from "head down" to "head up" during the final stage of the attack. Hence in AI.23B the entire attack was carried out "head down" using the CRT.
Posts: 43
By: crl848 - 4th May 2012 at 13:51
Right, I've managed to confuse myself looking at my copy of Stewart Scott's Lightning part 1 book.
P.18 has a summary of the initial test programme plan, under which development batch aircraft XG313 and XG325 are listed as "AI20/Blue Jay" and "AI23 development" respectively.
Later on (p.133) the use of these aircraft in the De Havilland Red Top trials is described by test pilot George Aird. He says "...there was no radar in the DB aircraft and the missiles fired were were just aerodynamic test rounds... We had no weapons system at all, no Pilot Attack Sight...".
Finally the unidentified DB cockpit pictured on p.31 has a PAS but no radar scope.
So. Were the aircraft not fitted with the planned radar/sight, or were these removed prior to use by De Havillands? Many thanks for any insight.