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[DBS]TH0R

B-25D - belly turret too effective?

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Thank you for finally contributing something useful to this discussion and my suspicion about the belly turret being ineffective. From the video above:

 

RAF_Mitchel-II_Mod2.thumb.jpg.54263cbdcfef4c53c81cbebd6779912a.jpgRAF_Mitchel-II_Mod1.thumb.jpg.54d079a3c49876210e549e9d569b04ba.jpg

 

- you can clearly see a modified Mitchel II (B-25D) bomber with installed 2 waist guns, together with a single gun in the improvised tail. C/P of the same mods USAAF has done in the field on their B-25C/Ds

- my educated guess would be that the belly turret was removed on that one

 

Furthermore, some more interesting details can be found in this article (sources - 4 books, can be found at the end):

 

http://www.airvectors.net/avb25.html

 

Quote

Additional armament was provided as well. Four 12.7-millimeter Brownings were fitted in blister packs on the sides of the fuselage below the cockpit, and up to three Brownings were mounted in the nose, though these nose guns were often removed. A single tail gun was fitted, with the gunner firing in a prone position. Later production had a raised position for the tail gunner. Waist gun positions were also added to later production, though the top turret was often deleted. The bomb bay was modified to handle mines and depth charges, and an underbelly rack permitted external carriage of a torpedo. When the 12.7-centimeter (5-inch) HVAR (high velocity air rocket) became available, ten stub attachments for these rockets were provided under the wings, giving the PBJ-1 tremendous salvo firepower.

 

Quote

Armament fit of the B-25G was otherwise generally similar to that of the B-25C/D, with top and bottom turrets and no tail guns. The remote-control bottom turret was deleted midway through production. The same scheme had been used in early combat versions of the B-17 and B-24 and had been found lacking with these aircraft as well. The worst problem was that sighting through a periscope tended to make the gunners airsick, and was a tricky task to begin with. Doolittle had found the whole idea ridiculous: "A man could learn to play the fiddle good enough for Carnegie Hall before he could learn to fire that thing." The turret also tended to get stuck in the down position, leading to unwanted drag, and the periscopic sight often got muddy or cracked during landings.

The B-17 and B-24 quickly converted to the manned Sperry ball turret for belly protection. Since the B-25 generally operated at low altitude, belly protection was judged to be low priority, and the turret was simply deleted. That helped reduce weight, which was important since the big M-4 cannon cut into the B-25G's performance.

 

The last paragraph most likely explains why RAF has kept their lower turrets, although your video shows that clearly some modifications USAAF used also found their way to RAF B-25Ds...

 

This implementation (later cheek guns on B-17s were a success) was clearly a fail, since it was deleted from several bomber types early on.

Edited by [DBS]TH0R
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Interesting discussion, chaps. Did anyone define what they meant by ‘effective’? As I look at it, bomber guns were for deterrence as much as anything especially when considered as part of a wider formation: as much lead in the air as possible, covering all angles of approach. Disrupting fighter attacks were an effective use of turrets, even if outright downings were far lower

 

Personally, I seriously doubt that a remote, non gunner-LoS turret likely put many rounds on target. But it would force fighters to make less efficient attacks and so saved aircraft, if somewhat indirectly. I avoid it in the sim, so maybe it is doing it’s job?

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Well, what I meant by "effective" is to track targets as easily and engage them with the same (gunner) reaction speed as the top turret. My opinion is that this was not possible with these turrets, and that this sim should try to simulate a discrepancy between top and belly one. Also, with dirt and cracks being mentioned, accuracy was probably lacking as well. But that is merely my assumption. :)

 

My in-game tests were not standardized by any means and represent merely an educated guess. Having that belly turret is, I will agree, a nice deterrent. Unless the attacker knows about its limitations / effectiveness.

 

When I find some free time, I would like to test this properly and conclusively.

 

 

Edited by [DBS]TH0R
(gunner)

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Blenheims tried a similar concept to defend its soft belly. A turret in the nose facing backwards and aiming with mirrors in a periscope. 
Like all turrets it added drag and weight, but it was utter useless because of lack of field of view. I think it was the shortest career in history. 
There are no doubt that all bellyturrets had problems but the only one worth having was mounted on US heavies. 
and remote controlled ones in B 29. The belly turret top turret could be controlled by one operator. 

Edited by LuseKofte

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44 minutes ago, [DBS]TH0R said:

Well, what I meant by "effective" is to track targets as easily and engage them with the same reaction speed as the top turret.

 

Yeah, I would doubt it was as effective as  a manned turret with space and a good view.

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3 hours ago, [DBS]TH0R said:

my educated guess would be that the belly turret was removed on that one

 

Ah, so you can lip read 1940's strine after all :) 

 

Joking aside, you are quick to cherry-pick the odd bomber out to fit it into your narrative, but don't forget the RAF also used Mitchell III's aka B-25J model, which had no bottom turret.

 

None of that alters the fact that the RAF used B-25C & D models aka Mitchell II's right through to the end in the ETO.

 

What you didn't spot in that film was the big difference between USAAF B-25D operation in the PTO & RAF B-25D operation in the ETO.

 

The dust & mud you mention very often, while certainly a factor on rough jungle strips in the PTO, dust in the dry season / mud in the wet, was not a factor for the RAF in the ETO as their B-25's operated from paved runways in a temperate climate.

 

This dirt & mud was the the main factor for removing the dustbin attributed by your B-25 pilot in his diary and in fact the only one he mentioned.

 

RAF Mitchell II's operating in the ETO did not have that problem. If they had, they would have been quick to ditch that turret not just for the weight saved, but for the trained air gunner now available for duty elsewhere.

 

=============================

 

That said, all your left with is an assumption that one turret is less effective than the other. That might be hard to prove. Personal anecdotal comments about playing the violin being just that, anecdotal.

 

Both turrets were operated by the same drive mechanism, Bendix, from what I've read. So the speeds for traverse & elevation should be the same.

 

Both gunners were on the intercom as was the whole crew, and trained to use it for spotting & tracking bandits, thereby sharing situational awareness.

 

Both turrets had the same armament, 2x .50"cal Browning's.

 

Where is this big discrepancy between the two that you seek? And most importantly, how can you prove it?

Edited by Pict
Spelling, tweaking etc.

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The video shows both the B-25D as we have it in-game, and the modified one. The former is featured at the end of the video, with the crew next to it discussing while it is being "bombed up".

 

11 hours ago, Pict said:

Joking aside, you are quick to cherry-pick the odd bomber out to fit it into your narrative, but don't forget the RAF also used Mitchell III's aka B-25J model, which had no bottom turret.

 

None of that alters the fact that the RAF used B-25C & D models aka Mitchell II's right through to the end in the ETO.

 

What you didn't spot in that film was the big difference between USAAF B-25D operation in the PTO & RAF B-25D operation in the ETO.

 

The dust & mud you mention very often, while certainly a factor on rough jungle strips in the PTO, dust in the dry season / mud in the wet, was not a factor for the RAF in the ETO as their B-25's operated from paved runways in a temperate climate.

 

This dirt & mud was the the main factor for removing the dustbin attributed by your B-25 pilot in his diary and in fact the only one he mentioned.

 

RAF Mitchell II's operating in the ETO did not have that problem. If they had, they would have been quick to ditch that turret not just for the weight saved, but for the trained air gunner now available for duty elsewhere.

 

There is a clear distinction between the Mitchel II (B-25D) and Mitchel III (B-25J). Without going into details, the most obvious distinction being top turret position which was moved forward, reasons being:

 

http://www.airvectors.net/avb25.html

 

avb25_04.png

 

 

Quote

avb25_08.png

 

The B-25H incorporated the Mitchell's first really practical tail turret, fitted with twin 12.7-millimeter Brownings. The rear fuselage was made deeper to accommodate the turret. There was also a single flexible 12.7-millimeter Browning on each side of the fuselage, in staggered positions behind the wing. The staggering of the side gun positions helped keep the two gunners out of each other's way.

 

The top turret was moved forward to behind the cockpit, where it could contribute to the forward firepower in strafing attacks, and was changed to a new NAA design that gave the gunner a better field of view and was better contoured to reduce drag. A pair of small bumps were added on the top of the fuselage behind the top turret to keep it firing into the tail.

 

The B-25J was effectively the same as a B-25H, but with no 75-millimeter cannon and a different nose, or more accurately a pair of alternate noses. The first was a glass nose with one flexible and two fixed 12.7-millimeter Brownings, and the second was a "strafer" nose with eight 12.7-millimeter Brownings. The longer noses resulted in the B-25J returning to the length of the B-25C/D.

 

Hence why, the one in the video looks like a B-25C/D with modifications done to it as described in the book and in the article linked above. B-25J also had a clearly different tail gunner position, and twin .50 unlike the single gun visible on that RAF bomber in the video.

 

Also interesting, from the same article, related to the B-25B:

 

Quote

* Doolittle considered the bombers available to the USAAF, and found the Mitchell the best suited for the job. 24 B-25Bs were modified at the Northwest Orient Air Lines center in Saint Paul, Minnesota for the mission. Armor was removed; the remote control lower turret, which nobody found particularly useful, was replaced by a 190-liter (50 US gallon) fuel tank. Other fuel tanks were added, increasing the capacity of the B-25B to a total of 4,320 liters (1,140 US gallons) from a normal capacity of 2,625 liters (694 US gallons).

 

 

As for the dust and mud being a problem only in the PTO, why do you think these turrets were then removed from B-17s and B-24s both operating in the ETO much more early in the war than the B-25s?. There was also a problem with cracks on the periscope prism, as described in the article above.

 

The extra special assumption here being that they only operated from concrete runways and there was no dust present on ETO airfields. :)

 

"The trained air gunner now available for duty elsewhere" is an even bigger assumption, with so many evidence available how they just gave the same gunner a different "tools" to work with (2 waist guns or a tail gun).

 

 

11 hours ago, Pict said:

=============================

 

That said, all your left with is an assumption that one turret is less effective than the other. That might be hard to prove. Personal anecdotal comments about playing the violin being just that, anecdotal.

 

Both turrets were operated by the same drive mechanism, Bendix, from what I've read. So the speeds for traverse & elevation should be the same.

 

Both gunners were on the intercom as was the whole crew, and trained to use it for spotting & tracking bandits, thereby sharing situational awareness.

 

Both turrets had the same armament, 2x .50"cal Browning's.

 

Where is this big discrepancy between the two that you seek? And most importantly, how can you prove it?

 

The only one throwing out anecdotes here is you, yourself here. OTOH I have provided sufficient reasonable doubt on the lack of effectiveness of the Sperry belly turret implementation below and behind the wings of a bomber on a center fuselage section.

 

Description of the discrepancy between top and belly turrets can be found in few posts above:

 

 

Together with my desire to test this thoroughly with repeatable results.

 

 

 

 

Edited by [DBS]TH0R
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I have no dog in this fight, but have to say that of the two opposing sides, one is quite convincing and documented. I’ m quite surprised that this side has no direct line with devs by the way.

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1 hour ago, [DBS]TH0R said:

Together with my desire to test this thoroughly with repeatable results.

 

Did North American, the people who built the aircraft not already test it? Was it not tested and approved by the USAAF? Did the British Air Ministry not test & approve it? Did the RAF not test it in combat and continue to use it?

 

Could be that if any of the above found any evidence to suggest that said turret was ineffective in any way that they would have documented that clearly. Why not look for that kind of documentation?

 

=====================

 

Like I said before and will say again, you might be right. I just have yet to see any solid compelling evidence that proves that you are right.

 

1 hour ago, KGM_Roll said:

I have no dog in this fight, but...

 

It's not a fight as far as I'm concerned, and I don't intend to let comments like that go unanswered without stating that clearly.

 

I don't see this as a fight nor intend it to be one. I would like to see clear proof of this theory, which as I have said already more than once may well be correct.

 

 

1 hour ago, [DBS]TH0R said:

The extra special assumption here being that they only operated from concrete runways and there was no dust present on ETO airfields. :)

 

I've already looked into that and the information regarding the bases that RAF Mitchell II's operated from in the ETO is readily available. I stated that they operated from paved runways in the ETO

 

At no point did I put forward the idea that there was only one type of airfield in the ETO.

Edited by Pict

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20 minutes ago, Pict said:

Did North American, the people who built the aircraft not already test it? Was it not tested and approved by the USAAF? Did the British Air Ministry not test & approve it? Did the RAF not test it in combat and continue to use it?

 

Could be that if any of the above found any evidence to suggest that said turret was ineffective in any way that they would have documented that clearly. Why not look for that kind of documentation?

 

=====================

 

Like I said before and will say again, you might be right. I just have yet to see any solid compelling evidence that proves that you are right.

 

USAAF tested and approved for service Sperry belly turrets across several bomber types. In practice, they were found lacking and replaced in later models. With some, even during production line. There are a many examples of tech that seemed useful in theory, past testing but in the end proved inadequate in practice.

 

In order to prove this beyond any reasonable doubt, books and materials about RAF Mitchel IIs would be of use. Can anyone help where to look for?

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4 hours ago, [DBS]TH0R said:

 

USAAF tested and approved for service Sperry belly turrets across several bomber types. In practice, they were found lacking and replaced in later models. With some, even during production line. There are a many examples of tech that seemed useful in theory, past testing but in the end proved inadequate in practice.

 

In order to prove this beyond any reasonable doubt, books and materials about RAF Mitchel IIs would be of use. Can anyone help where to look for?

 

The following info proves very little either one way or the other and is from Wikipedia, soooo....anyhow it could be a point from where to start looking further.

 

I highlighted the interesting part in red

 

https://en.wikipedia.org/wiki/No._98_Squadron_RAF

 

==============================================

 

220px-Mitchell_Mk.II_98_Sqn_RAF_in_fligh
 
A 98 Sqn Mitchell returning from France, 19 April 1944.

No. 98 Squadron reformed on 12 September 1942 at RAF West Raynham as a bomber squadron of 2 Group, flying the North American Mitchell II.[3][6] Relocating to Foulsham in mid-October, the Squadron continued training on the Mitchell, being declared operational on 8 December 1942, at first flying Air Sea Rescue (ASR) missions.[6] On 22 January 1943 the Squadron made its first attack on the enemy, when six Mitchells from 98 Squadron and six from No. 180 Squadron (also flying its first combat mission[7]), with an escort of Mustang fighters from 169 Squadron, attacked oil installations at Terneuzen, Belgium. One 98 Squadron Mitchell was shot down by German anti-aircraft fire while two of 180 Squadron's aircraft together with two 169 Squadron Mustangs were shot down by Focke-Wulf Fw 190 fighters. Following this inauspicious debut, 98 Squadron returned to ASR missions while modifications were made to the Mitchell's defensive gun turrets, the Squadron returning to combat on 13 May when six aircraft attacked railway marshalling yardsat Boulogne.[6] In August 1943 the Squadron moved to Dunsfold to take part in pre-invasion attacks on Northern France and on V1 flying bomb launching sites in the Pas-de-Calais. After the Normandy landings the Squadron operated in close support of the advancing Allied armies,[3] and from October 1944 was based at Melsbroek near Brussels, Belgium, moving to Achmer, near Osnabrück, Germany, just days prior to VE Day.[2]

 

=============================================================

What is meant by "modifications were made to the Mitchell's defensive gun turrets" is unclear and simply throws up more questions

 

Were some removed and replaced? 

Were others added?

Were some found to be ineffective and modified to be more effective?

Or any combination of the above.

 

However it puts RAF 98 Sqn in the cross-hairs for a more in depth look :) 

 

====================================

 

Update: The video I posted yesterday from the AWM (Australian War Memorial) was of "180 & 98 Mitchell Squadrons in England", and the bomber with the modified turrets was according to the AWM text "Mitchell bomber of No. 98 Squadron RAF taxiing returning into dispersal bay" *AWM is a very solid reference point.

 

So this was when they were still based in England and with the lack of invasion stripes, prior to D-Day.

 

More questions come to mind. Was this an experimental ship? There are still plenty of Mitchell II's with the dreaded dustbin present in that film, so were they modified in some way?

 

Funny thought my Australian jest may well have had some truth in it after all :biggrin:

 

Still looking....mostly for verifiable photos of Mitchell II's on bases in Belgium, especially RAF 98 Sqn at Melsbroek or actually come to think of it, any Mitchell II with invasion stripes will work too ;) 

Edited by Pict
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1 hour ago, Pict said:

Still looking....mostly for verifiable photos of Mitchell II's on bases in Belgium, especially RAF 98 Sqn at Melsbroek or actually come to think of it, any Mitchell II with invasion stripes will work too ;) 

 

Lots of images available out there, but happily I found exactly what I was looking for in a 2 birds with one stone fashion;

 

RAF 98 Sqn Mitchell II's at Melsbroek wearing full invasion stripes.

 

royal-air-force-2nd-tactical-air-force-1943-1945-raf-and-dutch-naval-ground-crews-prepare-to-load-50-f-in-wintry-conditions-at-b58melsbroek-belgium-M9YMHJ.thumb.jpg.3c51b17a6661191f82d8e9a83d24c85f.jpg

 

The dreaded dustbin (lower turret) is clearly present. So from this we know that they were used in this configuration well after any question was raised about gun turrets requiring modification as per the Wiki info above, which was dated 22 January 1943.

 

So, if the Wiki info is correct, can we assume that modifications were undertaken to make them satisfactory? Of course not :biggrin: 

 

=========================

 

I turned up another photo of an RAF 98 Sqn Mitchell ? like the one in the video, with the waist & tail guns, this time the call sign is Y-VO as opposed to D-VO in the film clip. Can't see the serial no's, so it's not sure if it's a different aircraft or not as coded can change. Semi invasion stripes on the fuselage put the date a bit after D-Day. 

 

Anyone know more about these? They appear to be neither D's nor J's, at least not production versions, but something part way in between.

 

RAF98SqnMitchell-Y-VO.jpg.bec2270f195c61197578e9cc69ada747.jpg

Edited by Pict
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interesting discussion, but I would be leery to declare the belly turret "ineffective" based on a comment in a book.

 

some points:

 

1. If remote controlled turrets were "ineffective", why did USAAF go the other way and instal a remote controlled chin turret on the B-17G? When B-17s did not have the chin turret, the preferred LW tactic was to attack B-17s from the front where they were defenceless. Once the chin turret was installed, frontal attacks were considered too dangerous by the LW. Does not sound like the turrets were ineffective.

 

2. Many RAF bombers, like the Lancaster, did not have a belly turret. The Lancaster was defenceless and had a blind spot from below. Because of this, the preferred tactic of LW nightfighters was to attack RAF bombers from below. The RAF was aware of this flaw, no doubt one of the reason they would have kept the belly turret on their B-25s.

 

3. You cannot compare the PTO and the ETO. B-25s in the PTO flew mostly over ocean or undevelopped jungle where long range was at a premium. They also never faced the AA/air opposition that bombers ran into over Germany. The LW had many heavy attack planes: Me-110/410, FW-190, Me-262 specifically to break up bomber formations that had no equivalent in Japan.

 

4. There seems to be a misconception that attacking unescorted bombers in daylight was a turkey shoot, but that was never the case even in 1943. It was very dangerous for a small group of fighters to attack a U.S. bomber unit because of all the fire power they could put up. You look at LW tactics and you see they were careful to mass maximum firepower to inflict the most casualties: 1) they would concentrate on one squadron, either out front or in the back; 2) they would send in the heavy attack planes: Me-110/410/FW-190s to try to break up the formation; and 3) when the formation was broken up, Me-109s would swoop in the finish off the stragglers.

Edited by Sgt_Joch
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Okay, I worked my way through this mess of a topic and one guy just asks for the lower turret to have less accuracy while the other is sperging all over the case because "RAF had turrets".

Did I paraphrase that correct? If so, I agree the lower turret should have a lower accuracy on the B25 due to it being a technically complex and demanding system.

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The B 29 had remote controlled turrets with seemingly good result. Turrets could interconnect eith eachother and operators was placed in domes where they could have situational awareness and sights. The same goes for the remote controlled front turret in B 17. 
it had a person sitting there with extremly good view and a sight. 
the turrets we are talking about is operated with a gunner that only had a periscope to help him. 
and apparently he got motion sickness by using it, like if your new to VR   The field of view he had was so narrow that even he was told where the fighter was , he probably never saw it in the periscope before it was too late

Edited by LuseKofte
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This is from the USAAF official history, description of the disastrous Schweinfurt mission in October 1943. It gives a good overview of LW tactics:

 

Quote

Wave after wave of fighters attacked. Usually a screen of single-engine fighters would fly in from in front, firing normal 20-mm. cannon and machine guns until very close to the formation. Closely following the single-engine fighters, large formations of twin-engine fighters appeared in waves, each firing large numbers of rockets from projectors carried under the wings. They lobbed their rockets into the bomber formations, generally from about 1,000-yard range and from the rear, making use of the natural advantage in sighting afforded by stern attacks. Like good duck hunters they fired at the leading element, knowing that the normal spread of bursts would be likely to give them hits. Meanwhile, the single-engine fighters refueled and attacked from all directions. Soon they were followed by re-formed groups of twin-engine rocket carriers. After expending their rockets, these twin-engine fighters frequently came in firing cannon and machine guns. The enemy aircraft concentrated on one formation at a time, breaking it up with rocket attacks (which by the way were, like flak, more effective for this purpose than for immediate destruction) and then finishing off cripples with gunfire. One combat wing of the 1st Bombardment Division, which bore the brunt of the counterattack, was almost completely wiped out by these tactics.99

 

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There's quite a bit of guesswork and chit-chat going on here.

  • First of all, the ventral turret of the in-game "B-25D (RAF)" is definitely simplified; for example: extending it and getting ready for combat took about 1 min
  • The RAF noted the shortcomings of the ventral turret, but it was indispensable over Western Europe 1943/44
  • The in-game "B-25D (RAF)" is a B-25D-20/-25/-30/ or -35 block - the RAF received copies of each
  • A number of those late block Mitchell II were delivered in the revised B-25D2 configuration (ventral turret replaced with waist guns & tail turret)
  • 2 Group did operate a few modified pre-D-20 Mitchell II (waist guns replacing the ventral turret, no tail turret) in 1945

 

I really want a B-25D2 modification if they are going to rework the Mitchell into a collector plane, but the standard configuration was omnipresent throughout the war and is absolutely essential.

 

1 hour ago, LuseKofte said:

The B 29 had remote controlled turrets with seemingly good result. ... The turrets we are talking about is operated with a gunner that only had a periscope to help him. 

The fire control system used in the B-29 and the ventral Bendix turret used in the B-25 are hard to compare.
Now, what about the periscope-sighted defensive armament of the Douglas A/B-26? It worked.

 

-------------------------------

1 hour ago, Sgt_Joch said:

The LW had many heavy attack planes: Me-110/410, FW-190, Me-262 specifically to break up bomber formations that had no equivalent in Japan.

Ki-44-II Otsu w/ Ho-301, Ki-45 Kai Hei or J2M for example.

Edited by =27=Davesteu
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I bet Pict is tons of fun at parties🤥

 

It should be quite obvious that a gunner using a gun fired upright, without a parascope, in a glass turret, will have (to a degree) an easier time spotting, tracking, and aiming than a gunner using a remote turret with a parascope. Even assuming the turret never got the poor reviews which it certainly did. It is also quite obvious that the gunners use the same AI to track, aim and fire, no matter what gun position they use.

 

However, I think trying to address the discrepancy opens a can of worms which is likely not worth the effort to clean up. The belly turret might be the most glaring drawback of using the same AI for all gunners, but where does it end if we decide to try and model the AI more precisely? it raises so many questions: open sights vs reflectors? Visibility effects? How about the Peshka waist gunner which tracks targets just as well as the Halberstadt gunner with severely limited visibility?

 

It is a valid observation, and totally worthy of discussion, but trying to address it raises so many questions about how far down the rabbit hole the devs should go, and will likely serve little purpose other than creating controversy.

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2 hours ago, Sgt_Joch said:

1. If remote controlled turrets were "ineffective", why did USAAF go the other way and instal a remote controlled chin turret on the B-17G? When B-17s did not have the chin turret, the preferred LW tactic was to attack B-17s from the front where they were defenceless. Once the chin turret was installed, frontal attacks were considered too dangerous by the LW. Does not sound like the turrets were ineffective.

 

That wouldn't be the same turrets that shot Thor down in his head on pass in the OP would it? He seems to think so :biggrin:

 

On 10/14/2019 at 11:21 PM, [DBS]TH0R said:

Belly turret was simply ineffective, it was removed in the field and in later models for a good reason (fun fact: those turrets were then used as cheek guns in B-17s).

 

=================================================

 

1 hour ago, Sturmalex said:

sperging all over the case because "RAF had turrets".

Did I paraphrase that correct?

 

Like a paratrooper that forgot his static line :biggrin:

 

 

1 hour ago, LuseKofte said:

The field of view he had was so narrow that even he was told where the fighter was , he probably never saw it in the periscope before it was too late

 

Do you have any figures or info on the periscope field of view angle? I've been looking for that but so far turned up nothing.

 

The turret gunner was on the intercom like the rest of the crew, see image below from B-25 manual.

 

2131493252_B-25lowergunturretinstallation.thumb.jpg.0b265a6e6ed7f3ff5f545b36bbf5cb9a.jpg

Edited by Pict

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10 minutes ago, Pict said:

 

That wouldn't be the same turrets that shot Thor down in his head on pass in the OP would it? He seems to think so :biggrin:

 

The B-17G gunner with a chin turret had a nice chair and more importantly - a full glass dome in front to track and acquire targets. Did not think such an obvious advantage needed explaining. :)

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2 minutes ago, [DBS]TH0R said:

Did not think such an obvious advantage needed explaining. :)

Sitting in that front dome of plexiglass seeing fighters and flak thrown at you, might not be seen as a “advantage” from the one sitting theres point of view. Aluminium did not provide better protection, but my guess is it still felt safer. 
About the periscope. I only looked in some modern ones in Submarine and artillery. 
I cant imagine the one in this turret is much better

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56 minutes ago, Cpt_Cool said:

I bet Pict is tons of fun at parties

 

I'm having so much fun I almost missed this little gem...

 

so are we talking metric or imperial tons here? ;)

 

57 minutes ago, =27=Davesteu said:

A number of those late block Mitchell II were delivered in the revised B-25D2 configuration (ventral turret replaced with waist guns & tail turret)

 

Thanks for that info, that's means that the RAF 98 Sqn Mitchell II's mentioned above in that configuration are indeed B-25D-2 production models.

 

So the modifications that were made to the Mitchell's defensive gun turrets according to the Wiki page referenced above are more likely to have been to the standard B-25D versions of the Mitchell II's that had the dustbin and most likely that it was the dustbin installation itself that was modified.

 

Unless anything better than that comes up, I'm happy to conclude that the RAF after taking a beating with the dusbin on an early sortie, addressed the problem sufficiently to keep it operational for the rest of the war.

 

Therefore no need to do anything drastic, other than have a party ;)

Edited by Pict

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4 hours ago, LuseKofte said:

Sitting in that front dome of plexiglass seeing fighters and flak thrown at you, might not be seen as a “advantage” from the one sitting theres point of view. Aluminium did not provide better protection, but my guess is it still felt safer. 
About the periscope. I only looked in some modern ones in Submarine and artillery. 
I cant imagine the one in this turret is much better

 

I don't think any position in a bomber when under fire or a head on pass was safe. :)

 

 

6 hours ago, Sgt_Joch said:

1. If remote controlled turrets were "ineffective", why did USAAF go the other way and instal a remote controlled chin turret on the B-17G? When B-17s did not have the chin turret, the preferred LW tactic was to attack B-17s from the front where they were defenceless. Once the chin turret was installed, frontal attacks were considered too dangerous by the LW. Does not sound like the turrets were ineffective.

 

The problem itself isn't with the turret mechanism, speed of rotation of ability to fire, rather the available view out to the gunner using it. Think of it as fully zoomed in vs. zoomed out in-game. Which do you think would give you a better view of your surroundings?

 

B-17G glass nose with reflector sight:

 

b17-nose-gunner-cockpit-m0a.jpg

 

vs. the periscope view of the belly position:

 

4 hours ago, Pict said:

The turret gunner was on the intercom like the rest of the crew, see image below from B-25 manual.

 

2131493252_B-25lowergunturretinstallation.thumb.jpg.0b265a6e6ed7f3ff5f545b36bbf5cb9a.jpg

 

The glass dome in the B-17G matched perfectly with the twin .50 Sperry turret. Or in other words, technical problems with jamming when lowering/retracting aside, the main problem was with the gunsight the belly implementation used - gunsight that cracked or got dusty and visibility out was hindered. The glass nose in the B-17G gave as good a view out as the top turret or a proper tail gun position.

 

 

4 hours ago, Pict said:

Thanks for that info, that's means that the RAF 98 Sqn Mitchell II's mentioned above in that configuration are indeed B-25D-2 production models.

 

So the modifications that were made to the Mitchell's defensive gun turrets according to the Wiki page referenced above are more likely to have been to the standard B-25D versions of the Mitchell II's that had the dustbin and most likely that it was the dustbin installation itself that was modified.

 

Unless anything better than that comes up, I'm happy to conclude that the RAF after taking a beating with the dusbin on an early sortie, addressed the problem sufficiently to keep it operational for the rest of the war.

 

Therefore no need to do anything drastic, other than have a party ;)

 

Jumping to conclusions now? Nice. Since when does operational = effective?

 

There are many reasons why I'd want to keep the turret on the plane provided there wasn't a better solution available. Here are just a few:

  • low number of D2 late production models available
  • belly turret even though ineffective, still serves as a deterrent
  • since it is late in the war, there is lower number of Axis fighters around*

 

 

* some B-17s late in the war flew without waist gunners.

Edited by [DBS]TH0R

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15 hours ago, =27=Davesteu said:

Now, what about the periscope-sighted defensive armament of the Douglas A/B-26? It worked.

 

Also featured problems, based on the Wiki article:

 

https://en.wikipedia.org/wiki/Douglas_A-26_Invader

 

Quote

A tractor-style "jump seat" was located behind the "navigator's seat." In most missions, a third crew member in the rear gunner's compartment operated the remotely controlled dorsal and ventral gun turrets, with access to and from the cockpit possible via the bomb bay only when that was empty. The gunner operated both dorsal and ventral turrets via a novel and complex (and problematic) dual-ended periscope sight, which was a vertical column running through the center of the rear compartment, with traversing and elevating/depressing periscope sights on each end. The gunner sat on a seat facing rearward, and looked into a binocular periscope sight mounted on the column, controlling the guns with a pair of handles on either side of the column. When aiming above the centerline of the aircraft, the mirror in the center of the column would flip, showing the gunner what the upper periscope was seeing. When he pressed the handles downward, as the bead passed the centerline the mirror would automatically flip, transferring the sight "seamlessly" to the lower periscope. The guns would aim wherever the periscope was aimed, automatically transferring between upper and lower turrets as required, and computing for parallax and other factors. While novel and theoretically effective, a great deal of time and trouble was spent trying to get the system to work effectively, which delayed production, and it was difficult to keep maintained in the field even once production started.[12]

 

The more information is presented here, the less I believe something like this (discrepancy between top turret) can even be simulated in-game. All of our planes are in mint conditions, why wouldn't a bloody turret then be as well? 😄 EDIT: I would still like to have the discrepancy simulated, if nothing else then by simply lowering the belly gunner skill level one or two levels below the rest of the crew (gunners). Simply because of so many documented problems with sighting mechanism of a said turret implementation.

 

I do want that B-25D2 mod though, closest thing to a B-25J. 😎

Edited by [DBS]TH0R

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Here is my current (most likely final) assessment of all of the above. Should detailed historical documentation of significance surface I might review it.

 

Wiki info regarding RAF 98 Sqn turned out to be taken from the Squadrons diaries, which have been collated into an interesting read here http://www.rafjever.org/98squadhistory3.htm


Mud/dust blocking the periscope view port

This one I can readily accept as a reason to remove the turret as it would render it useless, but only when mud/dust are persistent problem as was the case from jungle strips in the PTO. This can be proven not to be the case for the RAF Mitchell Squadrons in the ETO as they are documented to have operated from paved runways.

 

Cracked periscope view port glass

Chances of this happening on the runway are small and like all other accidental equipment damage can be put down to such. After T/O should the glass be found to be cracked in such a way that rendered the turret useless, RTB.

If this was a persistent problem affecting many aircraft it would have been investigated and if no solution found, it would have been the end of the turret as it would be deemed totally dysfunctional.

As the turret soldiered on till wars end in the ETO, we know this was not a problem. Why haul 2500 lbs of uselessness into combat for years?

 

Vertigo

This is a not so common medical condition, plenty of info available about it. Affects a small percentage of the population, more women than men and more in the old than in the young. As the aircrew were all medically fit young men, who trained on the equipment, the chances of having a gunner rendered useless in combat by looking through the turret gun-sight would be tiny.

It affects the crewman not the turret. If anything was to get rated novice by me it would be the person allowing a gunner suffering vertigo to go on combat ops. In the worst case scenario if you had the bad luck to have a gunner affected by vertigo in the combat area, you would just swap out the gunners.

Gunners were selected for their ability, some were good on some equipment, others not so hot for one reason or another. This is not the fault of the equipment.

 

The lower turrets were said to be unpopular

No surprise, I know what I would prefer given the choice. That has no bearing on the effectiveness of the equipment, but is just a reflection on aircrew preference when faced with an option.

 

Turret raise/lower mechanism prone to jamming

On reflection I find that this was actually quite serious and I think more serious than any of the above. As, if the turret jammed in the raised position it would be rendered useless. If it jammed in the lowered position it would slow the aircraft to the point of dropping it out of formation, or slowing the whole formation down. Add to that the info on hard landings when it was stuck in the lowered position.

 

This is what I think the RAF modifications were about, working out the bugs in the turret raise / lower mechanism.

 

Situational awareness

Bomber crews were a team connected to each other via an intercom. The situational awareness of each crewman was shared the with the team to create an overall picture of what was going on around the bomber, this is well documented.

 

An attempt to separate out different gunners situational awareness is to misunderstand how that gunner functioned in the defense of the aircraft as a whole. To argue that the lower turret gunner had less situational awareness than the top turret gunner and therefore conclude that he was less effective is easy to prove wrong.

 

Lets say on our bomber that one turret is rendered out of action for some reason, say an electrical/hydraulic fault or even just a simple ammunition jam. Our bomber is down one turret. But has our bomber suffered a reduction in situational awareness? No it has not. Therefore we are dealing with two different items, situational awareness of the crew and effectiveness of any given turret.

 

Should we persist with that flawed argument and treat each gunners individual situational awareness as the measure of how effective he is, then we must apply that to all bombers and their individual gunners.

Upshot of that is that we can see with ease that the upper gunner in an He-111 for example, has a much better individual view than the lower gunner, or waist gunner.

 

Should we then reduce the effectiveness of 4 of the He-111's gunners? Absolutely not, and for exactly the same reasons that we should not reduce the effectiveness of the B-25D lower turret gunner.

 

That about covers it for me. It's been fun, interesting and somewhat educational. Thanks :) 

Edited by Pict
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1 hour ago, Pict said:

Should we persist with that flawed argument and treat each gunners individual situational awareness as the measure of how effective he is, then we must apply that to all bombers and their individual gunners.

Upshot of that is that we can see with ease that the upper gunner in an He-111 for example, has a much better individual view than the lower gunner, or waist gunner.

 

Are you saying that:

 

"You would be just as effective (spotting, tracking, aiming,) through a parascope vs a firing station with unobstructed views "

Or

"Its not worth addressing (due to the subjective nature of relative turret effectiveness or other reasons)"

 

Because I agree with statement number 2, but it still seems like you are arguing statement number 1. Which is ridiculous.

 

Sure the crews had radios - but - have you ever been with somebody who points out, shall we say, a deer in the woods? Only you don't see it. Your friend describes where it is, points at it, you have an unobstructed view and the exact same viewshed. But it still takes you an embarrassing amount of time to spot it? Imagine doing that through a parascope (which, incidentally, disoriented people to the point of sickness), with the stress of battle, with only auditory help. No way in hell would it be just as easy to spot, track, and aim. Not a chance.

 

I have an idea. We will put you in a blindfold, give you a gun and a headset. Then a crew will call out apples for you to shoot off of imaginary heads. Don't worry, the apples can't move or shoot back.

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Having flown and trained as part of multi crew ops in war zones I think you underestimate how well a team can function with practice and experience, when you fly and live together and your combined actions effect real outcomes. 

 

Communication and situational awareness moves to the next level when you gel (and train as a team.) perhaps not  quite the same as friends deer hunting  (not intended as belittling) 

 

Not entirely relevant to all of the above posts, but it is an interesting point,

 

also a team that does not 'gel' can be at a big disadvantage regards efficiency, I have also flown in this situation and it is horrible 

 

Cheers, Dakpilot 

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The turret caused severe disorientation vertigo, it's very common in situations where the body and brain get confused as to what movement is affecting them, such as when reading in  a car - the brain thinks you're stationary, the body is moving, you feel sick. Also very common when looking through mirrors or periscopes that shift your field of view away from the direction of your head/neck, especially in situations where your body is also already moving laterally. Lastly I'm sure many of you regular VR users can attest to feeling Vertigo when first getting used to the headset. Some games can be extremely nauseating - moving your head a little, camera moving laterally, and rotating, all at the same time your actual body is reporting being still in  chair...? 

 

That's the vertigo we're discussing. Not the chronic condition.
I'm with @Cpt_Cool on this one, argue 2 all the way, production realities and all that, but arguing 1 is absurd.

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FYI - I can create a mod which redirects the B-25d belly turret so that it uses a separate AI configuration file (from that used by other gunners)... so I can modify:

- Burst length, the amount of time spent between bursts

- How often the AI switches targets,

- The range at which the AI opens fire,

- How much AI skill level impacts accuracy.

 

So, if anyone is willing to either provide references (and even speculation) about how the gunner should behave differently... I can set the files up. Similarly, if someone wants to do some testing.

Edited by Avimimus
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Thank you very much for your offer @Avimimus!

 

However, first I believe we should properly test whether there actually is a difference between the top and bottom turrets in B-25D. My testing in the first post was nothing more than a hunch, based on the facts I know from reading about the B-25s...

 

For proper testing, sadly, I don't have the time now.

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The turret configuration files have information on animation speeds (i.e. going from a retract to extend or sitting to standing positions; position switching speeds; reload speeds), turret firing arcs, turret rotation speed, and some values (e.g. parallax) for associating the turret with the floating aim-point overlay (if flying with the "hud" on and low difficulty settings). They also have the ammunition load, misfire chance, and tracer frequencies. The only thing which is possibly relevant and new is "FovH=" and "FovV=". However, these may be related to setting up the armour box rather than the gunner field of view.

 

In terms of the gunner behaviour ingame it would appear that everything refers to the same AI configuration file (shared with all other gunners). So aside from durability rotation speed, retraction, and weapons equipped the turret is identical in behaviour to all other turrets.

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9 hours ago, Avimimus said:

In terms of the gunner behaviour ingame it would appear that everything refers to the same AI configuration file (shared with all other gunners). So aside from durability rotation speed, retraction, and weapons equipped the turret is identical in behaviour to all other turrets.

 

Thank you for finding this data out. Looks like my hunch that they preformed the same was accurate then...

 

Is there any difference between the FovH and FovV between the two turrets?

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On 10/15/2019 at 10:22 PM, Pict said:

 

 

 

I think I now know how this came about, judging by this film clip the RAF had a secret weapon...

 

. All Australian crew leaving and inspecting aircraft after operations. Crew discussing operations with Flight Commander, smoking. Fuel tanker truck arrives to re-fuel aircraft. Aircrew return and watch Mitchell being bombed up for mission.

 

This is genius, off course all the nausea problems of an upside-down worldview through a turret periscope would off course not affect upside down australians.

Another WW2 secret solved!!

 

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I think we have a few different modes of things making the belly turrets ineffective in real life vs what would be reasonable to put into a flight sim. As it stands we dont simulate random part failure aside from when overdriving your aircraft, so i think that shouldnt be applied selectively. IE, i think the impacts of mud/dust and breaking the periscopes on landings should be neglected since the player always starts with a factory-new aircraft.

 

Next, there are several key points to consider with the effectiveness of the belly turret when it was working. The gimme one is the FOV. I'm going to go on a bit of a tangent here, but bear with me. A good tank crew knows their vehicle well-enough, and likewise knows their other crew members such that if any single crewmember says "I see something" on the intercom, everyone in the tank knows which sector that thing is in. If the crew is even more well-trained they can communicate IE:  driver says to the gunner "Gunner, something coming into your zone" The gunner then knows that there's something in front of the tank (As that's where the driver is looking) and if the gunner also knows where his own gun is pointing, he will also know where the target will enter his FOV from. This is nice and effective allowing incredibly quick response times despite the gunner's small FOV; however, it is a 2D scenario where it is unlikely for the gunner to miss a target. When you consider this initially for a standard gunner looking out a window, it should be fairly applicable -- If a target is about to leave gunner A's area and enter gunner B's area, then with a good crew A need only call out to B for B to know a target is approaching from A's sector. When the target then enter's B's sector the response time for B is fairly low, since B can likely scan the entire area between his sector and A's sector. When you get down to say something where it has the FOV of a WWII submarine periscope, you then have a lot less FOV to scan with. If a target passes into the belly turret's sector and is missed by the gunner, they may not even get a chance to shoot at it. 

 

How would I suggest this be setup? I'd give each turret a percentage chance to lose a target when it passes from one sector into another, with the percentage being variable depending on config settings per-aircraft (and maybe per-skill). If the turret fails and loses the target, it must search for the target using whatever methods the game may normally use (Maybe not since i've read a few accounts of how AI pilots know you're there as long as you are within the area they could possibly ever be looking at), or maybe add a target reacquisition delay that's a base time configed for each turret, + a little bit of randomness in the time so we dont actually have to calculate out when the gunner acquires the target. Really this would probably be nice to have on all aircraft which have turrets with the percentage and acquisition delay depending on the skill settings. 

 

For the vertigo portion, I think this something we need to look into more. Motion sickness and vertigo are highly variable depending on the person so unless this was a very big issue inherent to the turret design i'd air on the side of neglecting this if the FOV changes are taken. I would bet that the US has boxes full of reports about this if it were an issue (since we have reports on crew injuries from tank hatches, and literally have boxes of reports on the impact of mold on every rubber piece fielded in the PTO...). While it does seem likely, I dont think the sources we have here are sufficient to prove that the turret did cause significant vertigo issues in overall, really we have a single quote from Doolittle on the issue, and some forum posts of people saying that they did. If I believed everything WWII-related that i read in only one secondary source, then i'd believe the M4 Sherman was named after a union war general as an anti-confederate conspiracy, that the Japanese Class-A armor plating in WWII was vastly superior to anything the US could make, and that the M1 Garand made such an incredibly loud ping that it was an issue (to only name a few horribly, terribly incorrect ones). Any facts regarding WWII need to be taken from primary sources, preferably technical ones, and checked against other primary sources as the information can often be contradictory depending on the context the reader has. Failures to do this start myths as each new article does nothing but parrot a single statement regardless of the truth. 

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