Whooosh, Bang- UK's WWII Rockets

Bubbles_Barker

LE
Book Reviewer

tiv

LE
While searching the IWM site a short sequence of photos (H 16371 to H 16375) came up. Oddly there is a bearing scale painted around the bottom of the projector support that couldn't have been easy to use.

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large_H_016371_2.jpg
 
While searching the IWM site a short sequence of photos (H 16371 to H 16375) came up. Oddly there is a bearing scale painted around the bottom of the projector support that couldn't have been easy to use.

View attachment 607094View attachment 607095
I suppose it depends on whether the scale was intended to be used by the crew manning the projector or whether it was intended to be used by the battery commander to see whether the projectors were pointed more or less at the correct target or off somewhere else.
 
While searching the IWM site a short sequence of photos (H 16371 to H 16375) came up. Oddly there is a bearing scale painted around the bottom of the projector support that couldn't have been easy to use.

View attachment 607094View attachment 607095

Nice! You know what you've found there?
confirmation they were called 'Zeda projectors'. Why? Who knows at this point! but at least we have a name. Although it could be a typo for 'Zenda' which has been mentioned before. These sorts of notes were fairly prone to inaccuracies.
 
While searching the IWM site a short sequence of photos (H 16371 to H 16375) came up. Oddly there is a bearing scale painted around the bottom of the projector support that couldn't have been easy to use.

View attachment 607094View attachment 607095
I thought a lot of these system towards the end of the war were used to set up box barrages based on radar controlled gunnery systems.

I guess it’s difficult to see what’s behind the breech (?) there may be a cut out to allow them to read the base. (I.e you’re seeing 180 degrees off where they’re aiming from where the photo is taken.

There were mobile Z projectors as well.


I get the distinct impression they were used for firing a volley of rockets in the approximate direction of the enemy.

If a Z projector only needed a crew of 2 to operate it and the 3.7 inch needed a crew of 7 you’re onto a winner. Especially when you remember that until the introduction of the VT fuse, AA artillery wasn’t exactly useful other than as a moral boost.
 

tiv

LE
I thought a lot of these system towards the end of the war were used to set up box barrages based on radar controlled gunnery systems.

I guess it’s difficult to see what’s behind the breech (?) there may be a cut out to allow them to read the base. (I.e you’re seeing 180 degrees off where they’re aiming from where the photo is taken.

large_H_016373_1 copy.jpg
 
I thought a lot of these system towards the end of the war were used to set up box barrages based on radar controlled gunnery systems.

There was a fire control radar, as well as optical tracking. Each of these fed into a plotter, which outputted a modified baring and elevation for each of the projectors. The gunners then laid their projectors onto the designated settings, and when ordered the entire lot salvo'd. This is why you'll see Z Batteries with each projector laid out in a line.
No gunsights were provided or needed for this.

Interestingly, part of the defence scheme was to use the projectors against dive bombers. This requirement entered into the weapon when the Stuka was still considered an issue. One didn't need gunsights for that either, as they had a photo-electric fuse that acted as a proximity fuse. But you needed to be able to lay the weapon so it pointed roughly in the direction of the dive bomber, hence the little windows on the front.
You could also use hte PE fuse agaisnt level bombers, but it had to be daylight, and a German aircraft's life expectancy over the UK in daylight was.... Yeah, that's why you never see the PE fuses being talked about as they got no real use.
 
There was a fire control radar, as well as optical tracking. Each of these fed into a plotter, which outputted a modified baring and elevation for each of the projectors. The gunners then laid their projectors onto the designated settings, and when ordered the entire lot salvo'd. This is why you'll see Z Batteries with each projector laid out in a line.
No gunsights were provided or needed for this.

Interestingly, part of the defence scheme was to use the projectors against dive bombers. This requirement entered into the weapon when the Stuka was still considered an issue. One didn't need gunsights for that either, as they had a photo-electric fuse that acted as a proximity fuse. But you needed to be able to lay the weapon so it pointed roughly in the direction of the dive bomber, hence the little windows on the front.
You could also use hte PE fuse agaisnt level bombers, but it had to be daylight, and a German aircraft's life expectancy over the UK in daylight was.... Yeah, that's why you never see the PE fuses being talked about as they got no real use.
How did the director system give the data to each projector? Where there repeating dials on each one for the crew to follow?
 
Nice! You know what you've found there?
confirmation they were called 'Zeda projectors'. Why? Who knows at this point! but at least we have a name. Although it could be a typo for 'Zenda' which has been mentioned before. These sorts of notes were fairly prone to inaccuracies.
Ahem...
 

Tyk

LE
What was the practical rate of fire of those projectors? I can't imagine a salvo of rockets teararsing towards a bomber being a particularly welcome sight. Must have been a combination of brown trousers and downright impressive.
 
Possibly by intercom, the operator on the right is wearing headphones.

View attachment 607180
If it is by repeater where are they? Quite a lot of the information is relayed verbally in the action portrayed in this film.

EDIT

The thought occurs that with guns the predictor output seemed to be used to point all the guns (with an attempt at precision) at where the target will be. With a Z battery is the predictor used to point each projector at a place around where the target will be with no attempt at correction on to the target? Such an arrangement would be logistically simpler, the same prediction could be communicated to each projector crew via an audio circuit. It fits in with what we are seeing in the photos.
 
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With respect to fire control, a big of quick googling turned up the following:

The first describes the ring or scale.
World War II anti-aircraft rocket battery and bombing decoy control building 265m north east of Ashridge Farm
Each of the rocket bases conforms to a standard design, this being an octagonal base of concrete about 2.6m in diameter with a 1.2m square concrete ramp on one side of the base and a flared concrete apron at the other. At the centre of the base within a ring about 1m in diameter are six equally spaced bolt fittings for holding the rocket projectors which were probably 3 inch (c.7.5cm) projectors for fire against formations of bombers. Around the perimeter of each base was either a cast iron protractor ring calibrated in degrees, or an incised ring made by pressing the concrete with the raised lettering of one of the cast iron rings. This arrangement would have allowed for the aiming of the rocket projectors.

The second is an account by a Home Guard member who manned a rocket projector. The commands for bearing, elevation, etc. came over an intercom headset from the operations room.
Memories of the Home Guardicon for Recommended story by martin_p_h

Each projector could fire two 3" anti-aircraft rockets having a maximum altitude of 19,000 ft. and a ground range of 10,000 Yards (5.7 Miles). The heavy finned rockets were about six feet long and each had an adjustable nose fuse to be set to explode the warhead at the correct altitude. Two men manned each projector. The commands for altitude, bearing, elevation, loading, etc. came over a sound-powered intercom from the operations room to a headphone worn by No.1, who relayed the orders to No.2. Each man set a fuse, No.2 loaded the rockets onto their guide rails and pulled them down onto the electrical firing pins and then set the elevation wheel. The firing pins were connected via safety switches to a firing handle and a 6v. dry battery. No.1 set the bearing and reported "Charlie 5 ready" etc.; on the command "Fire", he depressed the firing handle. If the rockets misfired, we had to wait 20 minutes before unloading.

The sound powered headphone system was not very clear and probably was responsible for some early bearing/elevation setting errors. But some enthusiastic HG Marconi engineers soon designed a powerful valve (vacuum tube) amplifier to replace the official system. Before this there were a few near accidents. On one occasion the Railway Station-Master phoned the Battery Commander to complain about the flight of two lonely rockets, which had nearly shot down some of his wagons standing at the station. All the rest went in the direction of the enemy planes.

Both are worth reading in full, the Home Guard one in particular.
 
What was the practical rate of fire of those projectors? I can't imagine a salvo of rockets teararsing towards a bomber being a particularly welcome sight. Must have been a combination of brown trousers and downright impressive.

Weirdly, they actually tested the brown trouser effect. One night they sent some poor sod up in a plane and shot a couple of salvo's at him.

The results were:
1) Yes you can tell when the battery is firing due to the massive flash of the weapons igniting.
2) You can see the wave of rockets closing towards you.

It has been noted in another document the Germans were very shy of getting within range of a Z battery. They tended to veer away. I suspect unlike flak you very much could see you were being shot at, and it can't have been a fun few seconds watching 64 rockets hurtling towards you.
 
Now there's a find... I wonder if we can confirm it?

Apparently the Admiralty requested PAC for defence of aircraft carriers. Now, did it happen? I'm guessing its going to be an escort carrier, not a full fat carrier.

Edit:
Apparently it was Carriers in the Med, date of early 41.
HMS King George V had UP fitted - initially on B turret, but they were moved to bridge wings, apparently.
 

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