20mm cannon, best, worst, specs, comparison to LMG, HMG etc.

[riacrato]

yep. greater firepower. like the 2 x Mk108 'Kannonboot' under the wings the nose Mk108. or the 2 x rocket tubes. on a -109. I wonder how effective those
rockets actually were..

MK108 gunpods were never used operationally afaik

What I read about the 21cm Werfergranate used with Fw 190s it seems noone was ever satisfied with the results and the added firepower was probably offset by the additional drag. iirc their use was discontinued at least once and the were only reintroduced because there was nothing comparable.

I also don't think the R4M was particularly accurate, it was more like a shotgun.

 

[davebender]

I disagree. Post-WWII folding fin rockets are based on the R4M for a good reason. However the R4M entered service too late to make a serious impact on WWII.

I agree with Shortround6 concerning other WWII aerial rockets. Can you imagine employing a modern day 227mm MLRS artillery rocket against aircraft? Using a 21cm Nebelwerfer42 rocket against aircraft is essentially the same thing.

 

[P-40K-5]

MK108 gunpods were never used operationally afaik

I though there were at least a few with 2 x Mk108s that were in operational use.

What I read about the 21cm Werfergranate used with Fw 190s it seems noone was ever satisfied with the results and the added firepower was probably offset by the additional drag.

couldn't the rocket tubes be Jettisoned? That would take care of the drag/weight problem after its use.

 

[davebender]

Germany was working on a rocket pod for the R4M when the war ended. I expect it could be jettisoned.

Investing development money in the 21cm Werfer-Granate 21 would be like beating a dead horse. The system is never going to be effective.

 

[P-40K-5]

really? I though the WGr 21 Rocket launcher tube had explosive bolts so it can be jettisoned. interesting, thanks.

 

[davebender]

This discussion about fighter aircraft firepower has gotten me thinking.

The 3cm Mk108 hub mounted cannon provided plenty of firepower for killing WWII era heavy bombers provided the projectiles hit the target. So did existing MG151/20 cannon mounted in Fw-190s and Hs.404 cannon mounted in Spitfires. Rather then loading down fighter aircraft with additional weapons and ammunition all you need is a 30 lb gyro stabilized gunsight to put the existing cannons on target.

Why didn't gyro stabilized gunsights receive a higher priority for development?

 

[P-40K-5]

the EZ42 was used used in some Me262's and Fw190's. from what I read, it could hit targets with a 20* deflection
and could hit targets at 1500m. not to shabby. as far as development, maybe the priorities changed for fighters?
bigger(weapons) were better? etc.

 

[Rivet]

The German pilots did not like the R4M. As with most early unguided rocket developments the accuracy was nowheres near that of a rifled tube. This another bit of archania gleaned in a chance meeting in Savannah at the Mighty Eighth Museum.

Askania Werke gunsights at the end of the war were probably the best in the world, as well as being fitted to fighter developments they were used on anti-aircraft weaponry.

Research Lt. Col. Paul Irving Gunn for an in-depth understanding of the M-2 Browning as an aerial weapon. What that fellow did with the weapon won the Battle of the Bismarck Sea, a pivotal battle in the SW Pacific. Aviation vs. Naval Power. Regards

 

[Tante Ju]

Why didn't gyro stabilized gunsights receive a higher priority for development?

Problem was human element. Also in decision making, but think little. Gyro stab sight gives lead element - based on what? Speed of angle, and distance data. Distance data was always input by pilot.. with errors. Sight computed prediction based on those errors, so it is not instant problem solver. As long as pilot gave wrong distance (easy - in combat) sight gave complete wrong information.. pilot is going to miss. In many ways this can worse than manual prediction.

These sights were not mature until Korea war. On US side - then pilot need not interfere, sight distance was given by measurement of radar in F-86. So in my opinion, this was useful advancement, but I think it is bit over rated effectiveness in WW2. It was not auto solution. Also I understand fear of introduce more complex expensive sight. Both sides - by 1941, British, German had working sight.. but introduction delayed until 1944... probably of fear of great ranking offizier.

 

[Kryten]

accuracy becomes a mute point if the pilot is spending more time jinking about to avoid return fire, the rockets were after all an attempt to put a weapon that could outrange the .50's on the bombers onto a fighter!
large rockets are a desperation attempt to put a large fragmentation warhead into the box in the hope of causing damage rather than trying to hit a specific target which would have been nothing but insane luck to achieve!

gunpods are a poor substitute for a properly integrated weapons system, all that extra weight dangling below the wings has an adverse effect on both handling and climb, the germans got it right with the FW190 bomber killers,next to useless in a dogfight but thats totally missing the point, the 109 was left scrabbling around to find something effective!

 

[Shortround6]

Problem was human element. Also in decision making, but think little. Gyro stab sight gives lead element - based on what? Speed of angle, and distance data. Distance data was always input by pilot.. with errors. Sight computed prediction based on those errors, so it is not instant problem solver. As long as pilot gave wrong distance (easy - in combat) sight gave complete wrong information.. pilot is going to miss. In many ways this can worse than manual prediction.

These sights were not mature until Korea war. On US side - then pilot need not interfere, sight distance was given by measurement of radar in F-86. So in my opinion, this was useful advancement, but I think it is bit over rated effectiveness in WW2. It was not auto solution. Also I understand fear of introduce more complex expensive sight. Both sides - by 1941, British, German had working sight.. but introduction delayed until 1944... probably of fear of great ranking offizier.

I agree for the most part. They were not an automatic solution. They also needed the pilot to "track" the target for a short period of time in order to generate the solution.

One problem with Gyro gun sights is that you need gyros. I know that sounds basic but gyros were often in short supply. My grandfather made gyros in WW II. He worked for a 4 man company on the coast of Maine and the company owner even got gas ration coupons for his two seat private plane to help speed delivery. Gyros were in demand for certain flight instruments, auto-pilots, and bomb sights. They are made to very tight tolerances, close to watch making.

 

[Glider]

Gyro sights were in pretty widespread service in the RAF by the end of the war with an emphasis on fighter aircraft not GA for obvious reasons, but some were fitted to bomber gun turrets. UK Production at the end of the war was about 1,000 a month, USA production I have no idea but its safe to say it was significant with different factories producing versions for the USAAF and the USN. German produced about 750 during the war.

I would certainly agree when people say that the inputs were human and open to error but depite this the improvement in accuracy was very significant for the early ones which were soon taken out of service for practical problems, 100% for the MkII GGS which was the version produced for the RAF, USN and USAAF.

Human error was reduced by presetting the sight for the German Aircraft of the time and the pilot or gunner would select the aircraft and the sight did the rest.

The design may not have been fully mature but it was mature enough. A couple of quotes affirm this

The sights seemed to possess almost magical qualities. As an ex-Battle of Britain pilot stated: ' I look back on previous combats where the enemy escaped more or less intact, and realised that I could most certainly and easily have destroyed it if I had been using a good gunsight'. A demonstration was also staged for two pilots of the USAAF. One reported:

I believe this sight would improve gunnery at least 100 per cent. Shooting is at the moment for most pilots purely guesswork. A pilot cannot guess with this sight, due to this I am sure that at least the lower bracket of pilots (75 per cent) will improve their shooting to the level of the best gunnery shots now, and the best ones can do even better. It is easy to handle, and there is no situaiton it cannot handle as well as the GM2, and in most cases (90 per cent) it will do better

 

[Juha]

Hello
in Allied gyro gunsights the range measurement depended on the known spans of the known enemy a/c and worked reasonable well against them, probably against for ex Ta 152H the range question would have been more difficult before they got accurate info on its span. IIRC when RAF studied the effect of theGGS on accuracy by comparing effectiveness of GGS equipped Spitfire sqns against those with normal reflector gunsights, there was a clear improvement in accuracy but not an overwhelming one.

Juha

 

[P-40K-5]

Re: on deployment - Fritz Hahn notes some 200 were used in FW 190s and Me 262s.

Develepment was ongoing from 1935, the first EZ 40 was presented summer 1941. Hahn also shows some hit % with the standard Revi 12 and EZ 40 sight. At the short, typical battle 25-50% increase was seen against fighters and bombers (it was more pronounced for the non-manouvering latter types), and more at very long ranges. This was understood for the Bf 109F's 2x7.92mm. However, it didn't change a few rules of thumb : effective fire can be only performed at short ranges, long range fire is ineffective with either gunsights.

The EZ 42 was quite successfull : "Reports of pilots showed, that individual attacks could be performed at 20 degrees of deflection. Despite the max. range of the EZ 42 was specified as ca 1000m, there were multiple Abschüsse from 1500 m engagement distance.

Hahn quotes an Allied report comparing the 'American Gyro-gunsight' and the EZ-42. The US version showed up 20% larger errors in the neccessary deflection angle, which already at low angles measured up to 1 degree error (...die selbst bei kleinen Winkeln noch bis zu 1* Fehler betragen haben.)

The EZ 42 was stabilised by two gyroscopes. Apprx. 800 were produced, from July 1944, most were however produced in 1945.

 

[Glider]

Am I right in remembering correctly that the EZ40 wasn't put into production?

 

[Juha]

Hello
the results of the British study on the accuracy of Mk II GGS vs GM 2 reflector gunsight in 1944. The analysed 130 Spit IX combats with fixed-graticule sights 34 kills -26% of the total. Mk II GGS equipped Spit IX sqn 38 combats scoring 19 kills – 50% of the total.

Juha

 

[davebender]

Sounds like even early model gyro gunsights doubled weapon effectiveness. So 1 cannon plus a 30 lb gyro gunsight is as effective as 2 cannons without a gyro gunsight.

 

[Tante Ju]

Double is I think too much. GGS Sqn may shoot twice amount of aircraft per mission, but it is difficult to say how better is actual improvement in accuracy. There are many factor in air combat, sight is one.. no Squadron did same performance, even with same plane.. however, in one Squadron pilots, more successfull, wear red socks, in 4 mission shoot down 8 aircraft, other Squadron, wearing blue socks, only 10 aircraft in 30 mission... so wearing red sock gives you 6 times improvement..? Perhaps... but if you have 1000 mission sample, likely difference will be small or change..

From discussion earlier: EZ 40 (Askania) hit rate 6,3% at 200m, standard Revi 12, 4,5%, against fighter.. 400m: 1,3% vs 2%..

So its better, even near 50%, however actual difference is not so breath taking.. so out of 100 bullets fired, not 4 but 6 will hit? Sure better, but its still **** accuracy.. and plane do not destroyed from either 4 or 6 bullets.. and even less 1 or 2.. However if you go close.. soon 50% will hit. say 50 meter...

 

[Juha]

I agree with Tante Ju
especially the Mk II GGS sample was too small for any definite conclusion and in air combat there were so many variables. Of corse there was a clear indication of better results with the gyro sight but how great the improvement was, difficult to say without much more info on the raw material and still especially the GGS sample was too small.

Juha

 

[davebender]

Perhaps not but a gyro gunsight weighed only 30 lbs. Even a 10% increase in effectiveness would be worthwhile for such a small weight gain.