Best tank killer aircraft of WW2 Part I

[Erich]

quite a bit actually from what I understand before going over to the Bf 110G which they then shipped out all Do 217's. He then was transferred over as Gruppenkommandeur of II./NJG 5 flying the 110G-4 in which he was killed in a stupid accident. What sucks for me is that his kills confirmation of 12 have fallen off the face of the earth. I can only trace up to 7 right now............anyway I degress as this is a tank busting thread...........yo pass the 3.7cm bitte !

 

[lesofprimus]

Big Guns
Cannon with a calibre of 37mm and more have never become popular as aircraft weapons, despite many attempts to adopt them, both for air-to-air combat and for air-to-surface combat. Currently they are very rare. The main attraction of such weapons has always been the possibility of a single-shot kill of a large bomber, a small ship, or a tank. The disadvantages of these weapons are excessive weight, limited ammunition supply and low rate of fire. Recoil is also a significant problem, but in theory this is one that can be avoided by the development of recoilless guns. However, no recoilless gun has ever been really successful.

Early Experiments
Among the earliest cannon fired from aircraft were the Hotchkiss weapons of calibre 37mm and 47mm, weapons constructed with parts of the automatic cannon of the period. The 37mm was produced in significant numbers, and available in version with a long and a short barrel. A few hundred French aircraft were equipped with them during WWII; mostly on the Breguet 5 and the Voisin 4, both single-engined aircraft of pusher configuration. Because they were loaded manually, the rate of fire was very low; and they were not very effective in air-to-air combat. They were useful as ground attack weapons, however.

The French identified another possible use for large cannon: As anti-submarine weapons. During WWI aircraft were slow enough that a spotted submarine might be able to dive before the aircraft could drop bombs on it. A cannon extended the reach of the anti-submarine aircraft. This culminated in the concept of a "high seas flying boat", for which a specification was written in 1918. This would be an aircraft with a crew of four, an eight-hours endurance, and an armament including two machineguns, 120kg of bombs, and a 75mm cannon with 30 rounds! The aircraft designed to this specification never entered service, but the Tellier T.7 did serve as testbed for the 75mm cannon between 1920 and 1922.

In Britain too, experiments were conducted with a number of large-calibre weapons, mainly for use against balloons and airships, although they were also used for ground attack. Vickers delivered the Vickers 1½-pounder and 1-pounder guns, the 1.59in Vickers Crayford, also known as the "Rocket Gun" because its incendiary projectile left a trail of sparks, and the Vickers 1-inch gun. The automatic 1-pounder cannon, basically a much enlarged Maxim machinegun, was the most successful, but nevertheless remained rare. Its recoil was the largest disadvantage.

More common than the Vickers guns was a weapon developed by the Coventry Ordnance Works, the 37mm 1½-pounder COW gun. The COW gun was automatic, very light for a weapon of this calibre, and had a good ballistic performance. But nevertheless it was a bulky weapon, and it saw little service. During the the interbellum it was carried by a few large aircraft, and a handful of fighters were designed round it, but none of these installations was adopted by the armed forces. The weapon seems to have seen its only actual service on the ground, as anti-aircraft gun...

Cleland Davis designed the recoilless guns named after him. They were simple weapons, basically a barrel with two open ends; the recoil was compensated by firing a lead shot rearwards. The loading procedure required the barrel to be made in fore and aft pieces, joined at the center, so that the round could be inserted manually. Leaks at this joint were a serious design problem. Three versions were produced, a 2-pounder, a 6-pounder and a 12-pounder. Its service life, mainly as anti-Zeppelin weapon, was short. The lead shot fired from the rear, and the rearwards blast, made this weapon highly inconvenient to install in the fragile WWI aircraft. It was installed on some aircraft, but generated little enthusiasm among the crews who had to use it.

One of the first aircraft designed for a really large cannon was the Admiralty Type 1000, also known as the AD.1. The Admiralty's concern was the German fleet, and it planned three versions: A bomber, a torpedo bomber capable of carrying an 18 inch torpedo, and a gun machine armed with a recoilless Davis 12-pounder gun. The latter would be used to lob shells at small warships from a safe distance. Development of the giant seaplane began in 1915, and it was completed and flown in the summer of 1916. Concerns about the rearwards blast of the Davis gun caused to design to be changed for a 12-pounder Naval Landing Gun, a conventional cannon, that would be installed on a mount allowing 49 degrees elevation and 38 degress depression. In the end, no gun was ever installed in the AD.1.

Soviet Recoilless Guns
The recoilless Davis guns inspired the development by B.S. Stechkin and L.V. Kurchyevskii of a series of similar weapons in the USSR. Between 1930 and 1936, when he was arrested and disappeared, Kurchyevskii developed a series of guns, that were installed in experimental and even production fighters. The design of all these aircraft was influenced by the rearwards firing of a compensating mass. Either the guns had to be in the wings, or the barrel had to be extended to the extreme tail of the aircraft.

Project Z, also called TsKB-7, was a small low-wing monoplane fighter developed by Grigorovich. He used parts of the I-5 biplane fighter to speed development. The aircraft had a recoilless 76.2mm DRP under each wing, and a single 7.62mm PV-1 machinegun in the fuselage to assist in aiming. About 50 production aircraft, called I-Z, were built. But because they suffered from handling problems, and the DRP guns were single-shot weapons, they were mostly used for further development work. Grigorovich followed with the IP-1, a refined aircraft armed with APK-4 guns at the wingtips. These could fire five rounds. Although the IP-1 entered production, it was without the recoilless guns: The 20mm ShVAK was preferred. The IP-4, with four 45mm APK-11 guns, remained experimental. Later Grigorovich fighters still had heavy armament, but significantly, stuck with multiple conventional 20mm cannon.

Meanwhile, work had also been underway in Tupolev's design bureau. The ANT-23 had a highly original concept: The crew and the two engines, one tractor and one pusher, were installed in a small nacelle. The long barrels of the recoilless APK-4 guns actually formed the tail booms. However, when a shell exploded in one of the guns the ANT-23 barely landed safely, and the aircraft was abandoned. More promising was the ANT-29. This was a conventional, highly streamlined twin-engined monoplane, with a single 102mm DRP or two APK-8 in the fuselage. The ANT-46, a basically similar design, instead had two APK-11 guns in the wings, and apparently the design goal was to use the 100mm APK-100. But the arrest of Tupolev and the disappearance of Kurchyevskii ended the development of fighters with recoilless guns.

Tank Busters
The interest in large aircraft cannon was revived during WWII by the steady increase in the armour thickness of tanks. Most air forces discovered the need for dedicated anti-tank weapons for attack aircraft. However, experience on the battlefield showed that this was not always the best solution: Tanks were well protected against anything but a direct hit, and that was difficult to achieve. Soft-skinned supply vehicles or horse-drawn artillery where much more rewarding targets, but the power of a heavy cannon was wasted on them.

In the USSR, S.V. Ilyushin managed to convince the Politburo of the need for a modern, heavily armoured ground-attack aircraft. The first prototype of the Il-2 Shturmovik flew in 1939. With 990kg of armour, the Il-2 was always a modest performer and highly vulnerable to fighter attack, but it was well-protected against small arms fire from the ground. The Il-2 was, according to Stalin, as essential for the Red Army as bread, and about 36000 were built. This made it the world's most built aircraft, but such production figures were necessary to compensate for the heavy losses. Instead of large cannon, the Il-2 relied on high-velocity guns of small calibre. The initial armament of 20mm ShVAK cannon was insufficient, but they soon replaced by the powerful 23mm VYa. Only in 1943 a number were equipped with the 37mm NS-37. These were considered effective enough against the German tanks, because the rear and top armour was much thinner than the front armour.

P.O. Sukhoi, with his Su-6, had unsuccessfully competed with the Il-2: Although the Su-6 was a better aircraft, it was decided not to halt production of the Il-2. This did not deter him, and in 1942 he got approval for a long-range attack aircraft to complement the short-ranged Il-2. The Su-8 was a sleek, powerful, twin-engined aircraft, again with a heavily armoured cockpit. It could be armed with either four 37mm 11P-37 cannon, or two 45mm OKB-16-45 cannon. The latter were fed by clips. To assist in aiming, four 7.62mm ShKAS guns were installed in the wings. The Su-8 would have had the heaviest forward-firing armament of any WWII aircraft, but it was not put in production, because the war was nearly won. The line of thinking behind the Su-8 was continued with a series of anti-armour derivatives of the excellent Tu-2 twin-engined bomber. The second prototype of the Tu-2Sh carried a 75mm cannon, and the third carried two 20mm ShVAK cannon, two 37mm NS-37 and two 45mm NS-45. The Tu-2RShR had a 57mm RShR cannon installed in the lower fuselage. All these aircraft remained prototypes.

Initially, the Germans also opted for high-velocity cannon, but they did not have a direct equivalent of the VYa. Instead, the Junkers Ju 87G anti-tank aircraft appeared with two BK 3,7 cannon in pods under the wings, with six rounds each. The BK 3,7 was a 37mm weapon, developed from the Flak 18 anti-aircraft cannon. This armament installation proved highly successful against Soviet armour, despite the vulnerability of the obsolescent Ju 87 design. A purpose-designed attack aircraft was the Henschel Hs 129. As in the Il-2, the cockpit was an armoured box. With two Gnome-Rhone 14M4/5 radials, captured French engines, the Hs 129 was decidedly underpowered. It had a MG 17 and a MG 151/20 on each side of the fuselage, but the anti-tank cannon was carried in a fairing under the belly. It could be the 30mm MK101 or MK103, but also the BK 3,7. There were even experiments with the mighty 75mm BK 7,5, in an attempt to ensure the destruction of Soviet tanks, that carried increasingly heavy armour. Such 75mm cannon, the KwK 39 and PAK 40, also appeared on the Ju 88P, but their weight, recoil, and enormous muzzle blast were too much even for this twin-engined bomber. After the Ju 88P-1, later models switched to two BK 3,7 cannon, or one BK 5, derived from the PAK 38.

The RAF and USAAF never had an armoured ground-attack aircraft similar to the Il-2. Instead, they increasingly used fighter-bombers. Compared with the Il-2, these were more vulnerable to small arms fire from the ground, especially those with liquid-cooled engines, but on the other hand they could defend themselves succesfully against enemy fighters, and in general formed a force with superior range, speed, and flexibility. Both approaches can be defended. The Germans seems to have considered the Allied air superiority on the Western front more threathening, but then the front in the East was much longer, and air support was spread thinner.

Below, a table of anti-tank cannon carried by WWII aircraft. The ammunition specified in this table is the AP round used for anti-tank missions, which usually has a higher muzzle velocity than other rounds developed for the same gun.

Name Ammunition Rate of Fire Muzzle velocity Weight
MK 101 30 x 184B (355 g) 250 rpm 960 m/s 178 kg
MK 103 30 x 184B (355 g) 420 rpm 860 m/s 146 kg
BK 3,7 37 x 263B (380 g) 160 rpm 1170 m/s 295 kg
BK 5 50 x 419R (1250 g) 50 rpm 1200 m/s 540 kg
BK 7,5 75 x (3300 g) 933 m/s 1000 kg
VYa 23 x 152B (200 g) 500 rpm 905 m/s 69 kg
NS-37 37 x 195 (735 g) 250 rpm 900 m/s 150 kg
Vickers S 40 x 158SR (1130 g) 100 rpm 615 m/s 134 kg
Moulins 6pdr 57 x 441R (3170 g) 60 rpm 790 m/s 816 kg

Fighter-bombers could still be armed with large guns, and the Hurricane Mk.IID was fitted with two 40mm Vickers S cannon in pods under the wing, with two Browning .303 retained to assist in aiming. In the North African desert it proved effective, but the type was abandoned because it was vulnerable both to enemy fighters and to light AA guns, and its armament was considered to be ineffective against the newest German tanks. An alternative was the Mosquito Mk.XVIII with an Molins 57mm cannon, but this cannon too was rated unable to cope with the armour of a Tiger tank. The Mosquito Mk.XVIII, nicknamed Tsetse, was instead sent to Coastal Command for use against U-boats. The Allies switched to rockets as anti-tank weapons, and did not consider cannon again.

Near the end of the war a new breed of attack aircraft started flying. These were aircraft with the general configuration of light bombers, but a performance closer to that of fighter-bombers. A good example was the Beech A-38 Grizzly, a compact, clean aircraft powered by two mighty R-3350 radial engines. The A-38 carried the powerful T15E1 75mm cannon in the nose, with 20 rounds of ammunition. Unfortunately for the A-38, all R-3350 engines were required for the B-29 program.

 

[lesofprimus]

pics.....

 

[evangilder]

Nice writeup, Les. Hard to imagine a Mossie with a 57mm cannon!

The original P-38 design and all of the early models though the P-38D carried a 37mm cannon with 15 rounds of ammo. Obviously, 15 rounds aren't going to get you far and they went to the 20mm cannon with 150 rounds.

The solid nose attack B-25s did have a variant (B-25G) with the 75mm M-4 and 21 rounds, loaded manually. The M-4 was later replaced with the lighter T13E1 (B-25H). The barrel went through the tunnel that would normally be for the crew access to the greenhouse up front. The mod was done in New Zealand by North American engineer Jack Fox, working with Pappy Gunn. By the time they were readily available (Late 1944), the H model often flew without the 75mm due to lack of targets for it. It also had a slow rate of fire due to manual loading, which also was a reason to have it removed.

The B-25H also carried 16 x .50 caliber machine guns! It was mainly used for anti-shipping and ground attack missions in the Pacific. With the 75mm, it was quite effective against ships. The slow rate of fire would not have done well for tank-busting.

 

[GermansRGeniuses]

BUT, it could sink a large ship in something like seven shots...


AMAZING.

 

[plan_D]

Mosquito FB. XVIII "Tse-Tse" Named Tse-Tse Fly because it had more bite than a normal Mosquito. 6 pdr (57mm) Molins cannon with 25 rounds.

 

[cheddar cheese]

I prefer the BK 7,5 75mm cannon on the Hs-129B-2...

 

[plan_D]

I like that too but only 25 were built, weren't they?

 

[cheddar cheese]

I dont know the exact number, but it certainly wasnt many.

 

[plan_D]

I read they had some success in their short career. One hit from that 75mm would rip any tank apart, from the top. Same calibre as a Sherman M4

 

[cheddar cheese]

It was the plane that was bad rather than the gun. The cockpit was too cramped and the engines were unreliable. Wasnt too fast either...

 

[the lancaster kicks ass]

a 6pdr could ged rid of allot of things though..............

 

[Lightning Guy]

The USAAF drew up design specs for a version of the P-38 equipped with a 75mm gun that even Kelly Johnson wasn't aware of. The modification involved moving the cockpit forward to what was normally the armament section while the 75mm gun ran beneath the cockpit floor with the auto-loader sittting in the spot that had been the cockpit. 21 rounds were carried along with 300rpg for 2 .50cal mgs bracketing the cannon.

 

[the lancaster kicks ass]

the .50cal would proberly have been used to sight the 75mm................

 

[Lightning Guy]

That was the primary mission, but they also allowed the fighter to have some measure of self-defense as the 75mm weapon would have been useless in air-to-air combat.

 

[the lancaster kicks ass]

but 300rpg wouldn't last long at all................

 

[Lightning Guy]

24 secs. That would be comparable to the ammo supply on most marks of the Spit.

 

[the lancaster kicks ass]

wow didn't think it'd last that long, mind you i'm normally thinking about the .303...............

 

[cheddar cheese]

The USAAF drew up design specs for a version of the P-38 equipped with a 75mm gun that even Kelly Johnson wasn't aware of. The modification involved moving the cockpit forward to what was normally the armament section while the 75mm gun ran beneath the cockpit floor with the auto-loader sittting in the spot that had been the cockpit. 21 rounds were carried along with 300rpg for 2 .50cal mgs bracketing the cannon.

Woah, even I didnt know about that!

 

[DerAdlerIstGelandet]

Yeah I did not know that until now either, that is really interesting. I have found some info on it though since reading this last post. It was called the XP-58 Chain Lightning.

The XP-58 was the largest version of the series of aircraft based on the P-38 and continued with the XP-49. The "Chain Lightning" was initially designed as a long-range bomber escort, but was redesigned as a low-altitude ground attack aircraft and finally retro-designed back to a bomber escort/attack aircraft. Besides the many role changes, the XP-58 was plagued by engine, armament and crew changes. In the final configuration, the aircraft had two crewmen; a pilot and a rear-gunner operating two power turrets although the turrets and the forward firing armament was never actually installed. Engine and supercharger problems caused the project to be canceled after one aircraft was built.
TYPE
XP-58 Number built/Converted
1 Remarks
Larger version of P-38
SPECIFICATIONS
Span: 70 ft. 0 in.
Length: 49 ft. 3 in.
Height: 16 ft. 0 in.
Weight: 31,306 lbs. empty/38,874 lbs. gross
Armament: Designed for one 75mm cannon and two .50-cal. machine guns --or-- four 37mm cannons. Two rear-firing power turrets with two .50-cal. machine guns each.
Engines: Two turbo-supercharged Allison V-3420-11/13 engines of 2,600 hp. each
PERFORMANCE
Maximum speed: 430 mph. at 25,000 ft.
Cruising speed: 274 mph.
Service ceiling: 38,400 ft.
http://www.wpafb.af.mil/museum/research/p58.htm