Village Inn / AGLT developments.

[JFC Fuller]

I have been doing some very limited background reading regarding late war Lancaster variants and modifications and around the Avro Lincoln. Whilst Village Inn was being used in reasonable numbers by the end of the war (despite the issues with German homing equipment) the system appears to vanish after the war. Wikipedia mentions a AGLT Mark III that placed the scanner remotely from the turret, did this enter service? How come the system appears to have never been a standard fit on the Lincoln?

I am also curious as to whether any consideration was given to using the system with the other turrets, especially after the adoption of the twin 20mm dorsel turret on late model Lancasters and of course the Lincoln?

The systems post war vanishing act is odd given that the RAF did not lose heart in the tail warning radar, after all the Canberra got Orange Putter whilst Red Steer was fitted to the Vulcan.

This Lincoln is but it certainly has an AGLT installation for the tail turret so clearly the system was used with this type.

http://www.bredow-web.de/Museum_Cosford/Avro_Lincoln_BII/avro_lincoln_bii.html

According to this Flight Global article it was planned to develop the Lincoln's tail turret AGLT to fire the guns automatically!

http://www.flightglobal.com/pdfarchive/view/1950/1950 - 0182.html

 

[robunos]

Some information on AGLT Mk III, from
'British Aircraft Armament' volume 2, R Wallace Clarke, pp. 194-5 :-

"... The Mk III, however, was put into limited production. In this
version the scanner was not linked to the turret movement: when
a target was located, the scanner locked on...
and the information (was) projected onto the collimator.(the display unit)
This enabled the gunner to dispense with the continual searching
movement of the turret.
Testing was carried out by the Telecommunications Research
Establishment...
After lengthy development the Mark III was finally put into production.
The first operational squadron... was 101... in the autumn of 1944.
Soon after this, 49, 159, and 635 squadrons were converted.
These units found difficulty in operating the equipment and the
scanner drive mechanism gave trouble. (my bold)
Dr Hodgkin's (development) team continued to improve the system but...
large scale conversion of turrets was postponed. In september 1945,
proving trials were carried out...
but by this time there was no great urgency as hostilities had ceased."

From the above we can see that the AGLT Mark III did operate not very
satisfactorially, still being under development at the war's end.
Given also the prevailing view that there would be no further war for
ten years, by which time the Lancaster/Lincoln's jet-powered successors,
planned from the start not to be fitted with defensive armament, would
be in service, (OR.229 was issued in late 1946, B.35/46 following in early
1947), and I think there is the reason AGLT was not developed further.


cheers,
Robin.

 

[robunos]

I don't know where this Lincoln is...

The clue is in the link address you posted,
it's in the RAF Museum at Cosford...

http://www.rafmuseum.org.uk/cosford/collections/aircraft/avro-lincoln-b2.cfm


cheers,
Robin.

 

[JFC Fuller]

I found these images in my hard drive, note the AGLT installed in the tail. Note also that the installation of the lower barbette would prevent the aircraft from carrying the H2S bombing radar. I suspect that was one of the reasons why this concept never went into production.

 

[robunos]

It's a test aircraft for a remotely controlled turret system.
Referring again to British Aircraft Armament' volume 2, this time pp. 195-57,

"In May 1942, the Air Ministry placed an order for a...
remotely controlled turret system...
Boulton Paul, who would produced the barbettes, and
British Thompson Houston, who had experience of remote control systems.
The gunner would would occupy a sighting station in the tail...
The BTH control system employed an Amplidyne system...linked to a
'convergence computer', designed by the RAE...
By 1944 BP had completed the ...barbettes which passed their...tests in July.
The sighting...systems were not so advanced, for the requirements were so complex
as to require completely new technology.
The designers were gradually overcoming the problems, but were not very pleased when
the Air Staff made a requirement for the inclusion of AGLT radar tracking in the system. (my bold)
Development proceeded until...1945...
The system was finally passed for Service use in late 1945. The system was never adopted for two reasons.
Firstly, the development of radar sighting had reached a stage where the fire controller could
carry out [his duties]...from a central position...
and secondly, the jet bombers being designed would not need guns for protection."


cheers,
Robin.

 

[JFC Fuller]

Robunos,

Many thanks for the reply.

I suspect that the primary reason for types cancellation is contained in this phrase:

the development of radar sighting had reached a stage where the fire controller could
carry out [his duties]...from a central position...

To carry both barbettes a Lancaster or Lincoln would have to sacrifice its H2S or have less firepower than a Lincoln. The centrally located gunner would not occupy the tail so that position could be used for a barbette and the blind bombing radar retained. With the end of the war there was no need for the system to pursued too aggressively.

 

[Rickshaw]

Surely H2S could be carried elsewhere on the airframe? The Americans managed to put it onto the B-29 without sacrificing armament. You could even perhaps mount the scanner on one of the engine nacelles.

Oh, and there were plans to arm the V-bombers with self-defence weapons, as has been related elsewhere on this site.

 

[geeshockbloke]

How about this?

AVIA 6/15459 - Rear defence of fast bombers by guided weapons

from 1948.

Mark

 

[JFC Fuller]

Rickshaw,

The B-29 had the advantage of being a much larger and more powerful aircraft with a tricycle undercarriage. A quick look at a Lancaster shows that the only alternative location for the H2S was the nose, and that would mean adopting a Lincoln style remote nose turret and sacrificing the bomb aimers position!

geeshockbloke,

Work certainly continued after the war, elsewhere in this forum there is a proposed tail gun position for the Valiant that was to be remotely aimed using a radar. The tail mounted radar certainly survived with the Canberra getting Orange Putter and the V-Bombers getting Red Steer.

 

[Rickshaw]

Rickshaw,

The B-29 had the advantage of being a much larger and more powerful aircraft with a tricycle undercarriage. A quick look at a Lancaster shows that the only alternative location for the H2S was the nose, and that would mean adopting a Lincoln style remote nose turret and sacrificing the bomb aimers position!

Mmm, and the problem with that is? Alternatively, it would be possible to place the scanner under the cockpit, back from the nose. Your assumption that there could be only one place where a H2S scanner could be mounted appears to be falling to pieces.

geeshockbloke,

Work certainly continued after the war, elsewhere in this forum there is a proposed tail gun position for the Valiant that was to be remotely aimed using a radar. The tail mounted radar certainly survived with the Canberra getting Orange Putter and the V-Bombers getting Red Steer.

So, it appears the assertion that the Jet Bombers "being designed would not need guns for protection," was false as well...

 

[JFC Fuller]

Mmm, and the problem with that is? Alternatively, it would be possible to place the scanner under the cockpit, back from the nose.

Again, look at a Lancaster, and the size of a H2S radome, clearly there is not enough room in front of the bomb bay, which on a Lancaster continues under the cockpit. There was still a requirement for visual aiming where posssible. So nothing is falling apart.

So, it appears the assertion that the Jet Bombers "being designed would not need guns for protection," was false as well...

Was never my assertion.

See the attached images.


Edit: Both the B-24 and the B-17 sacrificed the ball turret, in service, in order to carry the H2X (AN/APS-15) radar, see attached images again, just as the Lancaster with would only have been able to take one 20mm barbette and H2S. So it seems that rickshaw's argument has not just fallen apart but has been ground into dust.

Edit 2: Handley Page Halifax, either a ventral turret or the radar scanner- not both, see attached images again.

 

[iverson]

I suspect that acceptance/use of AGLT was also limited by the RAF's experience with its earlier tail-warning radar, Monica. Monica was a disaster. It was a magnet for nightfighters--so much so that RAF offensive nightfighters used it to attract their Luftwaffe counterparts.

AGLT differed from Monica in that it was a more focused centimetric radar set. But by 1945, the RAF knew that the Germans could home on centimetric transmissions using the Naxos passive homer. This device homed on H2S. H2S was the RAF's only navigation aid that was effective independent of range, so the danger of using it was, rightly or wrongly, accepted. But, as with Monica, the limited protection that a sightly more effective gun armament could provide was probably not enough to offset the danger of adding yet another conspicuous transmitter.

Guns really did offer little protection at night. The famous physicist Freeman Dyson discussed this in his book "Disturbing the Universe". Dyson was assigned to operational research during the war and studied loss statistics. His unit's work showed that Luftwaffe nightfighters had such a marginal speed advantage over Lancasters that as little as a 20 mph improvement in the average speed of the latter would be enough to make interceptions almost impossible. Eliminating guns, turrets, and their crews provided just the weight and drag reduction needed to achieve this. Smaller crews also meant fewer casualties when aircraft were lost. Officialdom would not listen during the war. But afterwards, the logic took hold and British bombers abandoned the gun.

 

[iverson]

I am also sceptical of the idea that H2S had to be placed in the lower fuselage location or that lack of a visual bomb-aiming station in the nose was an insurmountable obstacle. Mosquitos operated with H2S installed in the nose even though this displaced the visual bombing equipment. Fortesses of 100 Group carried H2S under the nose and appear to have retained the bombardier's station. V-bombers carried their H2S in the nose with a visual bomb-aiming station immediately behind and below, in the lower fuselage.

I suspect that the rear fuselage just seemed like the most convenient location, all things considered. The lower turrets used in Lancasters were not very effective because the gunner could not see anything against the dark ground. Lower hemisphere attacks were also not perceived to be a significant threat until German the RAF realised that the Luftwaffe used oblique guns (Dyson discusses this in his book as well). So a rear-fuselage H2S installation preserved visual bomb-aiming at little obvious cost.

 

[JFC Fuller]

Mosquitos operated with H2S installed in the nose even though this displaced the visual bombing equipment.

In the case of the Mosquito the the original underbelly installation of H2S must have had a significant performance sacrifice to an aircraft that was dependent on speed, so relocation to the nose would make sense.

Fortesses of 100 Group carried H2S under the nose and appear to have retained the bombardier's station.

In the USAAF hat was an initial fit that was abandoned on later aircraft which sacrificed the ball turret. The RAF aircraft sacrificed the chin turret and only take the radar in that position because of the extra distance between the bomb bay and the nose.

V-bombers carried their H2S in the nose with a visual bomb-aiming station immediately behind and below, in the lower fuselage.

The system installed in the V-Bombers was a completely different and highly evolved system, not to mention the fact that the aircraft were designed from the outset to take it. Though thank you for pointing out that the aircraft retained a visual aiming position, clearly there was still a requirement for it.

I suspect that the rear fuselage just seemed like the most convenient location, all things considered. The lower turrets used in Lancasters were not very effective because the gunner could not see anything against the dark ground. Lower hemisphere attacks were also not perceived to be a significant threat until German the RAF realised that the Luftwaffe used oblique guns (Dyson discusses this in his book as well). So a rear-fuselage H2S installation preserved visual bomb-aiming at little obvious cost.

Exactly, without a very substantial redesign to the Halifax and Lancaster there was no way that the H2S could be mounted anywhere else on the airframe.

AGLT differed from Monica in that it was a more focused centimetric radar set. But by 1945, the RAF knew that the Germans could home on centimetric transmissions using the Naxos passive homer. This device homed on H2S. H2S was the RAF's only navigation aid that was effective independent of range, so the danger of using it was, rightly or wrongly, accepted. But, as with Monica, the limited protection that a sightly more effective gun armament could provide was probably not enough to offset the danger of adding yet another conspicuous transmitter.

The concept was certainly not abandoned, tail warning radars were developed for both the V-Bombers and the Canberra, though what became neccessary was better training for more disciplined use, same with H2S. However, for the lancaster generation it always struck me that AGLT was only part of the solution, what was needed was better armament behind it. The Boulton Paul Type H that was under development in 1942 (mid-upper) and the Bristol B.18 (tail) that was designed for the Windsor though rejected- both with twin 20mm Hispano's.

Of course the other option was to lose most of the armament and take the speed approach.

 

[iverson]

I think my point has been missed. Tail-warning radar and gun-laying radar are quite different things.

Gun-laying radar like AGLT is only valuable when you are going to let the enemy get within gun range. At that point, statistically speaking, a relatively low performance Lancaster was dead. A more heavily armed, more maneuverable opponent was in firing position and probably already firing.

Post-war tail-warning radar served a very different purpose: it helped high performance, usually unarmed bombers stay OUT of gun range. Given an initial altitude advantage, the post-war jets that used tail-warning sets had the performance to outclimb, out-maneuver, and/or outrun an interceptor that had to climb up after them and enter a tail chase. Even the RB-36 could escape jet fighters given some warning and plenty of altitude. Under the Featherweight program, RB-36s were stripped of guns for just this reason. If a MiG-15 or -17 got into a position where an RB-36 could get a shot in, the MiG had a firing solution of its own, and the RB-36 was going to lose.

Monica was thus a failure in night bombers. As a gun-laying set, it provided something that night bombers did not need for their survival--improved gunnery--while depriving them of stealth, the one thing that they did need. It was like trying to see a gunman on a dark night by hlding up a spotlight. As a tail-warning set, Monica was also a failure in bombers. British heavies had no speed or altitude advantage over enemy interceptors. Bomber tactics kept the bombers packed together in space and time and at low to medium altitudes so as to concentrate the bomb damage and saturate the defenses. There was not much that they could do with early warning warning, and, again, the emissions just drew the enemy to them.

Monica was, however, a success in bomber-support Mosquito nightfighters that had the performance to exploit the warning. Mosquito fighters had a large advantage in speed and acceleration over the usual Ju88 or Bf110 nightfighter. The Mosquito could stooge along in the bomber stream, imitating a heavy, until it picked up a Monica contact. Then it could do a maximum-performance 360-degree turn and, with a little luck, come up behind a German nightfighter that was still looking out ahead for the Lancaster it expected to attack.

The WW2 fascination with gun defense of bombers was a tragic error. That isn't an opinion--the operations research statistics show it and subsequent history has born it out. Mosquitos had the lowest loss rates of the war. Guns and turrets added weight and drag without contributing significantly to the survivability of a bomber (even USAAF YB-40 gunships could not survive in the face of fighter attack despite an armament that was much heavier than a Lancaster's). Thousands of bomber crews might have lived had that lesson been learned earlier and had Mosquitos replaced the heavies completely.

 

[iverson]

"The concept was certainly not abandoned, tail warning radars were developed for both the V-Bombers and the Canberra, though what became neccessary was better training for more disciplined use, same with H2S. However, for the lancaster generation it always struck me that AGLT was only part of the solution, what was needed was better armament behind it. The Boulton Paul Type H that was under development in 1942 (mid-upper) and the Bristol B.18 (tail) that was designed for the Windsor though rejected- both with twin 20mm Hispano's."

I believe that AGLT was tried with 0.50-in guns in the Rose turret. But more powerful guns weren't really the answer. They were even heavier, longer, needed more hydraulic power, traversed more slowly, and came with greater performance penalties. The Hispano was case in point. Windsor turrets suffered from vibration, which probably had much to do with the need to handle the mass and length of the weapon in a slipstream.

AGLT was also no more than an improved predictor gun sight. It solved the range problem and helped estimate lead and deflection more accurately. But it did not make the gun significantly more effective in real-life terms.

So, while tail-warning radar was not abandoned in Canberra and the V-bombers, guns were. A tail turret was considered for the Valiant, I believe, but not adopted. Maximizing the performance of the bomber with respect to the fighter and spoiling the fighter's aim--with chaff and ECM--proved much more effective than shooting. Guns disappeared.

 

[Rickshaw]

Mmm, and the problem with that is? Alternatively, it would be possible to place the scanner under the cockpit, back from the nose.

Again, look at a Lancaster, and the size of a H2S radome, clearly there is not enough room in front of the bomb bay, which on a Lancaster continues under the cockpit. There was still a requirement for visual aiming where posssible. So nothing is falling apart.

Then lose some of the Bomb bay. Visual aiming was over-rated anyway, considering the RAF had long adopted area bombing. By "in under the cockpit" I was referring BTW more to "just behind the nose".

If we talking about structural modification then an nose extension would not be out of place. The Lincoln Mk. 20 had a 10 foot nose extension for extra observer stations. This could have been done to the Lancaster as well as the room used to mount the H2S.

So, it appears the assertion that the Jet Bombers "being designed would not need guns for protection," was false as well...

Was never my assertion.

Errr, where did I claim it was. I merely said "the assertion". No personal adverb was attached.

See the attached images.


Edit: Both the B-24 and the B-17 sacrificed the ball turret, in service, in order to carry the H2X (AN/APS-15) radar, see attached images again, just as the Lancaster with would only have been able to take one 20mm barbette and H2S. So it seems that rickshaw's argument has not just fallen apart but has been ground into dust.

Edit 2: Handley Page Halifax, either a ventral turret or the radar scanner- not both, see attached images again.

They sacrificed the ball turret, just as the British heavies their under fuselage turrets because it was a convenient place to hang the scanner without altering the existing structure. However, if we are discussing a more extensive modification to accept a remotely aimed set of barbettes, then why not make the modifications necessary to mount the scanner elsewhere? I still tend towards removing it entirely from the fuselage and placing it under one of the wing nacelles, perhaps with a fuel tank on the other side to compensate for the increased weight.

Nothing has "fallen apart" except your original assertion and the other assertion about the v-bombers. Remember the adage, "loose lips sink ships"? Well, loose assertions sink arguments as well.

 

[JFC Fuller]

Windsor mountings vibrated because they were mounted in outer engine nacelles in flexible wings. The Bristol B.18 turret that I mentioned never suffered from vibration as it was never installed, only produced in mock-up form but rejected in favor of engine nacelle barbettes.

There is not a huge amount of difference between AGLT and something like Orange Putter, especially as AGLT seems to have been used as a tail warning radar. The difference with AGLT was that it was plugged into an effector.

Then lose some of the Bomb bay. Visual aiming was over-rated anyway, considering the RAF had long adopted area bombing. By "in under the cockpit" I was referring BTW more to "just behind the nose".

And if you look, there is insufficient space between the front of the nose. If you lose bomb bay you sacrifice bomb carrying capacity- so cant go there either.

If we talking about structural modification then an nose extension would not be out of place. The Lincoln Mk. 20 had a 10 foot nose extension for extra observer stations. This could have been done to the Lancaster as well as the room used to mount the H2S.

You mean the Mk.30, and that was as an MPA. The lincoln was also a much more powerful aircraft and the fuselage extension a very significant modification. We were not talking about never considered structural modifications, but actual aircraft.

They sacrificed the ball turret, just as the British heavies their under fuselage turrets because it was a convenient place to hang the scanner without altering the existing structure. However, if we are discussing a more extensive modification to accept a remotely aimed set of barbettes, then why not make the modifications necessary to mount the scanner elsewhere? I still tend towards removing it entirely from the fuselage and placing it under one of the wing nacelles, perhaps with a fuel tank on the other side to compensate for the increased weight.

Exactly, mounting it elsewhere in a useful operational fashion would have required very significant redesign, as the aircraft were there was nowhere else to place the scanner.

Nothing has "fallen apart" except your original assertion and the other assertion about the v-bombers. Remember the adage, "loose lips sink ships"? Well, loose assertions sink arguments as well.

My original assertion still stands- the Lancaster could not have carried the H2S anywhere else and you have been completely unable to discount it. And what V-Bomber assertion?

 

[GUNDAM123dx]

Hello guys, I've made an AGLT video in Chinese language (cuz I post it on chinese website) https://www.bilibili.com/video/BV1jF411W7i2/.
And there're two films of Village Inn & AGLT from TRE. I used some part of them (Original English sound) in my video .

However it seems they are still in private copyright (https://www.radararchive.com/?page_id=34) or something. (i'm not sure about copyright laws in US or UK. me Chinese.) So maybe I cannot just post the two original films here. Plz contact me for them if it's ok.

And document AP1093C (edit: page26), AP1093D (edit: page51-61) talked about AGLT in detail. Pretty useful.

 

[Wurger]

Hello guys, I've made an AGLT video in Chinese language (cuz I post it on chinese website) https://www.bilibili.com/video/BV1jF411W7i2/.
And there're two films of Village Inn & AGLT from TRE. I used some part of them (Original English sound) in my video .

However it seems they are still in private copyright (https://www.radararchive.com/?page_id=34) or something. (i'm not sure about copyright laws in US or UK. me Chinese.) So maybe I cannot just post the two original films here. Plz contact me for them if it's ok.

And document AP1093C, AP1093D talked about AGLT in detail. Pretty useful.

Any chance of sharing the missing parts/chapters? AGLT aren`t included.

 

[Justo Miranda]

Hi

 

[Justo Miranda]

Post-2

 

[GUNDAM123dx]

Hello guys, I've made an AGLT video in Chinese language (cuz I post it on chinese website) https://www.bilibili.com/video/BV1jF411W7i2/.
And there're two films of Village Inn & AGLT from TRE. I used some part of them (Original English sound) in my video .

However it seems they are still in private copyright (https://www.radararchive.com/?page_id=34) or something. (i'm not sure about copyright laws in US or UK. me Chinese.) So maybe I cannot just post the two original films here. Plz contact me for them if it's ok.

And document AP1093C, AP1093D talked about AGLT in detail. Pretty useful.

Any chance of sharing the missing parts/chapters? AGLT aren`t included.

AGLT are already included in these two files. Try look again carefully.
update: Page 26 in AP1093C. Page 51 to 61 in AP1093D.