WW-II tech questions

I didn’t think the FuG 202 was “the first operational night fighter radar,” but I wasn’t certain without checking.

Andy: You’re quite right about AI Mk IV having two CRTs, one for azimuth and one for elevation. Why did I think there was only one? I must be going senile! :rolleyes:

The Blenheim success of July 1940 was achieved using an AI Mk III set, but this was still experimental equipment and very limited in its ability. This is why the success of 22/23 July 1940 was, I think, the only ‘kill’ ever achieved with AI Mk III. That, of course, is why I mentioned AI Mk IV in my original post and referred to it as “the first British AI radar which saw large-scale operational use.” AFAIK, AI Mk III was the first airborne radar to see operational use, but I’d be interested to know if this is incorrect.

Hi All
I think the FuG 202 LIchtenstein BC set entered service in 1942 (probably the second half).
It operated at about 490 MHz at a power output of about 1.5 KW.
Range about 2 miles maximum down to about 650 feet where it would have up to the pilot to visually acquire the target.
The RAF had AI as it was known to us Brits in service much earlier than this.
The first succesful night combat using AI was carried out on the night of 23rd July 1940 when a Blenheim Mk1F of the FIU shot down a Dornier 17 of 2/KG3. I think the AI set carried in this instance was probably earlier than AI MkIV which was the first British set in ‘mass’ production.
AI MkIV had a similar performance to German set but had an even lower frequency.
The display was the split type with two CRT’s showing azimuth on the left and elevation on the right.
I know an ex RAF radar nav from this period and he tells me that after a while one gained the knack of reading the left scope with the left eye and the right scope with the right eye.
The squadron MO’s were very strict on eye testing and monitoring because the eyes could be become strained and therefore useless quite quickly.
If the original postee wants to contact me off list I’ll gladly point him in the right direction for further reading.
regards
Andy Jones.

Originally posted by Distiller
@1) The first operational night fighter radar was FuG 202 “Lichtenstein BC” on Me110’s

Can I ask when the FuG 202 came into service? I didn’t think radar-equipped Bf 110s were in service until mid-war, but I confess to not knowing a great deal about German airborne radar.

The U-boats in by March 1943 could fire FAT (circling type) torpedoes, and they also had acoustic homing torpedoes, to home onto the engine noise from a ship. This could be countered by towing a pnumatic drill inside a watertight container behind a ship, which the torpedo would home onto instead.

On the Allied side, by July 1943 a homing torpedo, the Mk 24, (code name ‘Fido’) was in use, and in late 1944, the air-dropping of Sonobouys came into use.

Geoff.

@1) The first operational night fighter radar was FuG 202 “Lichtenstein BC” on Me110’s (1.5kw impulse at 490MHz). The display was divided into 3 displays of 8cm diameter: (i) target distance (ii) relative height deviation (iii) relative sideways deviation. The WSO gave the pilot directions, but no real blind firing took place, since the pilot had to accquire the target visually (exhaust flames and the smell of exhaust gas) or with an IR scope, then he usually fired from well under a hundred meters. The other way was to bring the night-fighter on a head-on course with the help of the radar (and ground-based radar operators) and fire with automatically triggered upward-firing quad 20mm guns when passing under the bomber at high speed.

@2) No. The German T5 “Zaunkoenig” (= wren) used accustic homing.

@3) Enemy convois: SIGINT, aerial reccon, other subs, spys on land. Enemy vessels: binoculars from the sub or from high above on a “Bachstelze” towed gyroplane. Own position: stellar navigation, plotting like any other vessel. Radar: some had, but only navigational, not for accquiring targets

Off the top of my head I seem to recall that there was a stage in the war where a few U-Boats were lost for no apparent reason – until reports surfaced that their torpedoes were turning around and sinking them! Whether this meant that there was some form of ‘hunting’ radar involved or just that the torpedo had an inbuilt search patten to follow – which failed – I don’t know. Whether this still makes the torpedo dumb I don’t know either. – Nermal.

I’m not quite sure I understand what you mean by the first part of question 1. Like all radars, the first airborne interception radars worked by sending out radio energy and receiving the re-radiated energy. I suspect that this isn’t what you mean, and if you can clarify what you want to know I’ll do my best to answer.

With regard to the second part, the first British AI radar which saw large-scale operational use (AI Mk IV) consisted of a single display with a vertical line down the middle. The distance down the line where the target blip appeared indicated its range from the night fighter, and the extent to which the blip was larger to the left or the right of the line indicated the bearing of the target relative to the night fighter. There are a large number of books available on the subject, many of which include drawings showing these displays which are much easier to understand than my explanation.

As regards U-boats, I don’t know a great deal off the top of my head, but I do know they did have some radar equipment, certainly in the latter part of the war. This was, IIRC, for the detection of aircraft whilst on the surface, rather than for seeking ships to sink. U-boats were also equipped with radar detectors which would indicate if an Allied aircraft had seen the U-boat on radar, giving it time to crash-dive. However, the Allies started using microwave radar which this detector could not receive and thus the Allies were able to attack a lot of U-boats on the surface without warning.

The U-boat question would be dead reckoning and astral fixes.
Basically running a plot from leaving port and relying on that.
As for targeting the Germans had spies in the U.S ports – merchant ships of friendly nations who would pass on sightings
of convoys and the use of maritime patrol aircraft.
The was also the intelligence evesdropping on radio chatter
which the Germans could pick up snippits from.