Anything at all on AI Mk. 25

Maury Markowitz

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I've come across a few fleeting references to AI Mk. 25, supposedly for Hawker Siddeley P.1154. But now I can't find anything.

The naming is curious. It suggests that it was designed after Mk. 24, which seems highly unlikely! Or maybe they skipped a few numbers?

Does anyone else have anything on this, or perhaps better google-fu?
 
Maury Markowitz said:
I've come across a few fleeting references to AI Mk. 25, supposedly for Hawker Siddeley P.1154. But now I can't find anything.

The naming is curious. It suggests that it was designed after Mk. 24, which seems highly unlikely! Or maybe they skipped a few numbers?

Does anyone else have anything on this, or perhaps better google-fu?


I have seen references to "AI Mk 24" in the mid/late 50s in connection with other planned radars after AI Mk 23. There was the Aspinall CW radar, AI 18 derivatives, J Band AI 23 and other designs planned at that time. Its likely that this AI Mk 24 has little to no connection to Foxhunter. It just means "the radar after AI Mk 23", with AI Mk 25 being the radar after that.
 
Incidentally, I believe the "Aspinall CW radar" was a Radar Research Establishment design by Rueben Aspinall, CBE. He was a key figure in the development of coherent radar in the UK.

http://www.purbeckradar.org.uk/penleyradararchives/documents/aspinall/letters/index.htm

These letters contain lists of the extensive information Mr Aspinall had on his post-war work on Guided Weapons. This was all passed to CHiDE for safekeeping and will be available there.

Obtain docs on CD here: http://www.purbeckradar.org.uk/penleyradararchives/request/
 
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So first point is that there was work post '57 on new radars leading to a system that was intended first for the Or.346 aircraft, this being as FMCW system, but trials where disappointing. Treasurey approval in Oct '57 for a proof of concept 200W search only FMCW AI set aiming fora range of 50nm.

However the backup option was to move to PD and this option was ultimately put into action at the end '62 as a FMICW system. Flights proved the concept, such that this was the basis in '62 for the new X-band AI set for the P1154B, aiming for a 60nm range against a Canberra sized target with an auxillary Q-band using the same dish for use in ECM conditions.
By '64 this program was on good shape, but when the Admiralty abandoned the P1154B in the later part of the year, the program was downgraded to a research project looking at future AI and AEW technologies.
During '65 the AFVG lent new impetus to the effort but now Elliot was leading rather than G.E.C. constraints meant the X-band only system could be fitted into a trials Canberra as the indended use of a Valient for the full set suffered from the grounding of the Valient fleet. Flight trials began in Sept '66. The porgam suffered from a rationalising act in '66 as there was no need for a UK developed AI set, and so the flying was stopped in '67.

The ADV concept of the MRCA (Tornado) was on the cards from '69, and definition of the AI set for it was during '69 as a AI set using X-band FMICW of 1.5 -2kW. In 1970 the verdict was that it was not only possible but desirable to pursue a UK based solution and by '71 the earlier Elliot set was flying again in support of the effort.
Proposals by MEASL and Ferranti in '72 both being X-and 2kW FMICW with high PRF.

So I think we can answer that, AI.24 was always the designation of the new generation AI set after AI.18, but AI.25 might (and I stress might here) be an option for scaling the system down to fit the Sea Vixen's nose as the orriginal OR.346 to P1154B effort was a 36" dish and 32" sub-reflector.
 
Just came back to this thread now. zen, that does seem like reasonable speculation but was the Vixen not already "done" by the time MRCA was being considered?
 
Just came back to this thread now. zen, that does seem like reasonable speculation but was the Vixen not already "done" by the time MRCA was being considered?
Well not really this is more before MRCA and after P1154B for the RN....if not during the P1154B fiasco.

So the logic is they re-looked at extending Sea Vixen life or new build to get something to AW.406
Likely this is the similar time frame to exploring CF.299 on the Sea Vixen.

I guess the theory was if the radar missile combination could deliver the desired results then the Sea Vixen was proven operable from the CV Fleet.
In the end the F4K was chosen as the quick and interim solution, while the AFVG was the long term.
 
AI radars, in 1963 - 1966 timeline:

Hughes/EMI Pulse-Doppler radar for P.1154 (800lb weight)
Ferranti OSIRIS Pulse-Doppler radar for the P.1154
Elliott coherent radar proposal for Lightning
GEC incoherent MTI module for AI Mk 18 adaptable to AI Mk 23
Ferranti / Hughes coherent MTI module for AI Mk 23 (based on CORDS for the AN/APQ-109)

From Tony Wilson, English Electric Lightning - Genesis & Projects
 
During 1964 BAC proposed fitting a P.45 fighter variant with a pulse-doppler radar with a 30in (76cm) diameter dish (with an option for 36in) for a radar-guided version of the HM.45 (licence-built Hughes GAR-11 Falcon).
Presumably it would have been one of these radars?
 
AI radars, in 1963 - 1966 timeline:

Hughes/EMI Pulse-Doppler radar for P.1154 (800lb weight)
Ferranti OSIRIS Pulse-Doppler radar for the P.1154
Elliott coherent radar proposal for Lightning
GEC incoherent MTI module for AI Mk 18 adaptable to AI Mk 23
Ferranti / Hughes coherent MTI module for AI Mk 23 (based on CORDS for the AN/APQ-109)

From Tony Wilson, English Electric Lightning - Genesis & Projects
Clearly both a minor revelation to us mortals and an excellent advert for the book. I will place it on my list.....an ever expanding list that is becoming completely unachievable.
 
AI radars, in 1963 - 1966 timeline:

Hughes/EMI Pulse-Doppler radar for P.1154 (800lb weight)
Ferranti OSIRIS Pulse-Doppler radar for the P.1154
Elliott coherent radar proposal for Lightning
GEC incoherent MTI module for AI Mk 18 adaptable to AI Mk 23
Ferranti / Hughes coherent MTI module for AI Mk 23 (based on CORDS for the AN/APQ-109)

From Tony Wilson, English Electric Lightning - Genesis & Projects
FWIW, there were four proposals solicited for the P1154 coherent AI, from Hughes/EMI, Ferranti, Elliott and GEC/Westinghouse
 
How much detail us available on these 4 options?
 

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