OS2U-3

OS2U-3

SB2U-2

OS2U-3

SB2U-2

USA

I Rank

Battle rating:

AB	RB	SB
1.0	1.0	1.0

Class:

Bomber

Light bomber

Hydroplane

Research:2 000

Purchase:2 100

Show in game

Description

The OS2U-3 Kingfisher is a Rank I American hydroplane with a battle rating of 1.0 (AB/RB/SB). It was in the game since the start of the Open Beta Test prior to Update 1.29, however the vehicle was removed from the American air forces tree in Update 1.57 "Battle March". Those players who acquired the aircraft before it was removed still have access to it.

OS2U-3 Kingfisher is a delicate eye appealing float plane (beauty is in the eye of the beholder) of mid-wing monoplane design with a large central float and two smaller floats, one under each wing. Designed in second half of the 1930s it served throughout the WW2 primarily in the US Navy as catapult launched scout plane. As such it had long endurance and was often used for Search and Rescue operations. In War Thunder it is classified as a bomber and placed at Rank 1 in US Navy branch immediately after OS2U-1. Main difference from OS2U-1 are additional self-sealing fuel tanks being added in the wings and armor protection for pilot (seat and windshield).

Kingfisher is not an agile plane and has a low top speed. Offensive armament consists of a single 7.62 mm (0.30 cal) gun (with 500 rounds) which requires prolonged periods of time with sights on target to reliably do significant damage. It has a gunner also equipped with a 7.62 mm gun, however while his firing arc is relatively wide, it does not cover six o'clock low (low and behind the plane) so be wary of enemies approaching from that angle. Occasionally it will set an enemy on fire, snipe his pilot, or even do critical damage but frequency of this happening strongly depends on gunner's skill. Also, you can take gunner view and try shooting it down yourself.

In addition, Kingfisher can carry two 100 lbs bombs capable of destroying most ground targets and landing crafts, however, these require extreme accuracy since are very weak and have a small blast radius.

For these reasons Kingfisher is among most players considered overall bad plane, but do not be discouraged. Sure, this is no RP and lions farming machine but (mostly in Realistic and Simulator battles) it can be fun to immerse in the time of WW2 on different locations, especially over Pacific.

Overheating is not an issue with Kingfisher. Relatively low power air-cooled engine will not overheat while keeping it at 100% throttle even on warm maps (Pacific, Mediterranean maps). Overheating temperature for oil is 105°C and for engine 260°C. Effectiveness of oil cooling is more dependent on air temperature and engine cooling on speed at which air travels over the engine. WEP-ing (War Emergency Power) for long periods will overheat the engine in most conditions, while oil will overheat only at low altitudes (< 2 km on warm maps). To cool down simply pull throttle back from WEP to 100%.

General info

Flight Performance

Stat card

Characteristics
Stock
Max Speed (km/h at 6,550 m)		Max altitude (meters)	Turn time (seconds)		Rate of climb (meters/second)		Take-off run (meters)
AB	RB		AB	RB	AB	RB
278	527	6,130	35.6	39.0	11.9	12.4	305
Upgraded
Max Speed (km/h at 1,700 m)		Max altitude (meters)	Turn time (seconds)		Rate of climb (meters/second)		Take-off run (meters)
AB	RB		AB	RB	AB	RB
306	565	6,130	31.1	33.1	17.2	14.1	305

Details

Features
Combat flap	Take-off flap	Landing flap	Air brakes	Arrestor gear
✓	✓	✓	X	X

Limits
Wing-break speed (km/h)	Gear limit (km/h)	Combat flap (km/h)	Max Static G
			+	-
405	350	360	~18	~18

Optimal velocities
Ailerons (km/h)	Rudder (km/h)	Elevators (km/h)	Radiator (km/h)
< 200	< 200	< 240	> 250

Compressor (RB/SB)
Setting 1
Optimal altitude	100% Engine power	WEP Engine power
1,376 m	400 hp	450 hp

Engine performance

Engine
Engine Name			Number present
Pratt & Whitney R-985-48 9-cylinder			1
Engine characteristics
Weight (each)		Type	Cooling
290 kg		Radial	Air
Engine power (Stock)
Mode	Max		Take-off
Arcade	364 hp		415 hp
Realistic/Simulator	360 hp		411 hp
Engine power (Upgraded)
Mode	Max		Take-off
Arcade	446 hp		496 hp
Realistic/Simulator	400 hp		450 hp

WEP Duration
Arcade		Realistic/Simulator
25 seconds		Infinite

Survivability and armour

Examine the survivability of the aircraft. Note how vulnerable the structure is and how secure the pilot is, whether the fuel tanks are armoured. Describe the armour, if there is any, also mention the vulnerability of other critical aircraft systems.

Armaments

Offensive armament

The OS2U-3 is armed with:

• 1 × 7.62 mm Browning machine gun, nose-mounted (500 rpg)

Suspended armament

The option available for the OS2U-3 are:

• 2 × 100 lbs AN-M30A1 bombs

Defensive armament

The OS2U-3 is armed with:

• 1 x 7.62 mm Browning machine gun, dorsal turret (600 rpg)

Usage in the battles

Kingfisher is classified as a bomber and as such it spawns at altitude. Primarily, it should be used in ground attack role across all game modes. If possible, stay out of sight of the enemy and try to take indirect routes to desired targets. Single 7.62 mm gun is capable of destroying artillery, AAA (stationary and on trucks) and armored cars. Tanks and light pillboxes cannot be destroyed with such a small MG caliber but only with bombs. Cargo ships will require a single 100 lb hit on deck. Landing crafts may be taken out by gunfire but will require lots of hits.

Principal way of accurate dive bombing with the Kingfisher.

Arcade battles

At the start of the battle dive to the side and let your team to engage first enemy wave. Then when they are engaged in fight and distracted approach enemy ground targets. As the main goal is to remain undetected as long as possible always choose targets closer to the edge of the map.

When you are lower than the enemy it is harder for him to see you against the ground. Also, enemy must approach much closer before your marker (name tag) shows up while at the same time his marker will show earlier. What distance will enemy's marker show up depends on weather conditions (clouds), altitude difference and pilot's skill.

If more maneuverable enemy gets on your six (any biplane and most of monoplane fighters), and you cannot escape it, try jerking, shaking and changing heading in random fashion while the gunner does his work. Arcade flight model is more forgiving and will allow some aerobatics. This is especially viable if the enemy has only low caliber guns such as Kingfisher's. Use this time to reach friendlies. Alternatively, get in the gunner's view and try to deal damage to the attacker.

Even though it has no wheels it can land on airfields but touchdown must be gentle and at low speed to avoid serious damage. After repairs it will be spawned in the air. In “Domination” mode, where the goal is to seize enemy airfields by landing on them, Kingfisher can be used for capture but once landed it cannot takeoff immediately. This coupled with dynamic nature of arcade battles usually leads to loss of the aircraft, therefore it is best to use it in last effort to turn the tide of the battle.

Realistic battles

This is where bomber spawn comes in handy. Dive to the side of the map and start approach to remote enemy ground targets. By doing so chance to be detected by the enemy is minimized even more so than in Arcade. Observe the sky and report any spotted enemies to your team.

In RB and SB modes flight model is realistic and the lack of powerful engine will be obvious. Thanks to its low Power to Mass ratio of about 0,13 kW/kg (P-26A Peashooter has 0,29 kW/kg) acceleration and climb rate are very poor. Energy retention is not Kingfisher's strong side either. Every hard turn will drain its energy and it will lose altitude rapidly. Attempts of performing any difficult maneuvers, such as loop, are not advised before gaining some altitude and reaching decent speed (over 200 km/h IAS) otherwise the plane will stall out and plunge in the ground or become an easy target.

Since Kingfisher was never equipped with a bomb sight there is no bombing reticle in RB. Another important thing is that in this mode both bombs will drop at the same time. Therefore, dive bombing technique is to be used. To hit a target climb a few hundred meters (250 m at least), line up with the target at least 1 km out to avoid lateral movement at final approach, when 500 m from the target start diving at an angle (30° or more – steeper the angle and higher the speed, less lead on target is needed), aim just above it, drop the load and pull out. Light tanks should be attacked from the back as it is easier to follow their movement. Try this in test flight before trying to pull it off in a battle.

Bombs can be set to explode not on impact, but with delay, too. This option makes ground attack safer since it gives the attacking aircraft more time to exit the blast radius. Kingfisher has a few things in its favor when preforming dive attacks. First, low speed and low wing loading make pulling out close to the ground very easy. This means higher chance of scoring a hit. Another thing is small blast radius. While it requires high precision at the same time it lowers the chance to cause damage to the aircraft. If chosen to perform low bomb release 1 sec delay will give enough time to leave the blast radius and avoid damage.

After offensive ammo has been consumed ground attack can be continued with gunner's MG which has unlimited ammo. Approach the target in low level flight, after passing it pull up in shallow climb and switch to gunner's view to destroy it.
When landing on water aircraft must be close to a carrier to repair. Approach it from the stern and stop at bow because most carriers will be moving and plane needs to stand still during repair/reload.

Simulator battles

Aircraft's characteristics and advice mentioned in Realistic battles section apply to Simulator mode as well.

Cockpit visibility is decent but thanks to gunner's view this aircraft has excellent potential for situation awareness in simulator mode and this is what sets Kingfisher apart from majority of its opponents. Zooming in while in cockpit will activate telescopic sight which, while great for landing shots on distant targets, may be slightly bothersome because it narrows the field of view.

Events

Once in a while under in-game Events & Tournaments tab there will be Floats event. It is Arcade event for float planes such as Kingfisher in which, among others, it will encounter H6K4, and PBY-5a. Stay away from their six because their gunners will shred Kingfisher to pieces in matter of seconds. Wait for them to land in an attempt to capture zone, then drop 2 x 100 lbs on them. When other options exhausted, you can resort to ramming. It is perfectly acceptable tactic when you are outmatched by these multi engine beasts. Try to approach them from the front or sides to avoid most of their gunners. Their fuselage is very strong so avoid it and aim for the wings.

Modules

First modification to research should be Mk. 41 which allows installation of two 100 lb bombs. Next, focus on performance and survivability upgrades: fuselage repair, radiator, compressor, engine, wing repair, airframe and cover. Weapons upgrades can be left for last. These will allow the use of more effective ammo belts.

Manual Engine Control

MEC elements
Mixer	Pitch	Radiator			Supercharger	Turbocharger
		Oil	Water	Type
Not controllable	Controllable Automatic pitch	Controllable	Not controllable	Combined	Not controllable	Not controllable

Pros and cons

Pros:

• Bomber spawn.
• Gets to participate in Floats event (infinite fun).
• Can land on water.
• Telescopic sight (RB).
• High minimum fuel load.

Cons:

• Low top speed.
• Poor acceleration.
• Poor climb rate.
• Low Power to Mass ratio.
• Small burst mass due to single 7.62 mm.
• Poor energy retention.
• No bombing reticle in RB, SB.
• Telescopic sight (SB).

History

OS2U Kingfisher built by Vought-Sikorsky Aircraft Division was catapult-launched observation floatplane designed by Rex Beisel (a design engineer responsible for F4U Corsair). Kingfisher was assembled using a revolutionary spot welding construction which created a smooth fuselage that generated less drag. It also had number of innovative features, such as deflector plate flaps and drooping ailerons used to create additional lift at low speeds which improved control of the plane.

First prototype XOS2U-1 flew in 1938 and first production variant was delivered in early 1940. Despite its modest performance it gradually started replacing Curtiss SOC Seagull biplane and ended up as U.S. Navy's main ship-launched scout plane during WW2. It stayed in use much longer than expected because its successor Curtiss SO3C Seamew suffered from various issues, most notably engine failures.

OS2U-3 first flew on 17 May 1941. It was very similar to OS2U-1. Main difference from its predecessor was additional self-sealing fuel tanks in the wings and improved armor protection for the pilot. It had a 450 hp (336 kW) Pratt & Whitney R-985-AN2 engine (all Kingfishers were powered by different versions of this engine). It was armed with a 7.62 mm gun in the nose (hidden inside engine compartment) and a 7.62 mm gun in dorsal turret on flexible ring mount. Also, apart from 100 lb (45 kg) bombs it was able to load 325 lb (147 kg) of depth charges. The OS2U-3 was the most produced variant with just over 1000 units built. It was the only exported variant and it served in many countries from Uruguay to Australia including the Soviet Union aboard cruiser Murmansk (USS Milwaukee). Last of the Kingfishers were withdrawn from service on Cuba in 1959.

Kingfisher landing near USS Massachusetts in 1944.

While some were deployed to land bases (OS2U-2 installed with wheels instead floats were mostly used for training) most of Kingfishers operated from U.S. Navy's heavy and light cruisers and battleships. Violent launch was done into the wind by catapult powered with a cannon shell. Landing required ship to make a turn in order to create patch of relatively calm sea surface where Kingfisher could land and then taxi to the “sled” used to pull it closer to the ship's crane which would hoist it back on deck.

In the early 1940s seaborne radar was a rarity and still primitive, the eyes and ears of a fleet of warships were limited at best. This is where the observation aircraft was imperative. A battleship would launch a Kingfisher seaplane and the aircraft could then patrol the surrounding seas for hundreds of miles for hours at a time. Depending on the threat, the Kingfisher might be looking for anything as huge as an enemy fleet or as small and deadly as a single enemy submarine. In the case of the latter, the Kingfisher had teeth of its own: even with its limited payload, Kingfishers assisted in the sinking of U-Boats U-576 and U-176. Simply finding a target or enemy fleet was of immense use to the bridge crew of a warship, but the Kingfisher could do more. Once an enemy fleet was identified it was almost inevitable that an engagement would take place – even in the 1940s, naval guns were well capable of firing shells in excess of 20 miles. The Kingfisher could fly over an enemy fleet and report directly back to the bridge crew of any warship within its own fleet, giving real time feedback of the accuracy of shot and corrections to bring the tremendous firepower onto a target. Furthermore, the importance of naval gunfire did not stop with engaging other vessels: carrying some of the largest guns in the entire world on a mobile platform, battleships were the ultimate fire support during an amphibious assault. As US Marines fought their way from beachheads all across the Pacific theatre, the guns of the fleet were often there to eliminate concentrations of enemy troops and heavy defensive positions. Again, the Kingfisher was ideally placed to ensure this supporting fire was accurately and efficiently delivered.

Even though it was used in many different roles, as trainer, bomber, anti-submarine platform in the Atlantic, scout, naval gunfire spotter etc. the Kingfisher was most respectable for Search and Rescue missions where it was involved in saving downed airmen in the Pacific. On one occasion in 1942 over Pacific a B-17D became disoriented, ran out of fuel and ditched. After drifting for several weeks without food and water crew and passengers were rescued by a Kingfisher. With all the survivors on its wings it could not take off and started taxing to nearest island before being relived by a torpedo boat. However, most notable rescue happened in 1944 over Guam when a Kingfisher of USS Indiana rescued two downed airmen despite being exposed to fire from several nearby Japanese artillery positions.

The only confirmed kill scored with Kingfisher happened on 16 February 1945 at Iwo Jima where Lieutenant D.W. Gandy shot down a Zero fighter.

Media

Camouflages & skins

Skins and camouflages for the OS2U from live.warthunder.com.

• "Special skin for 'Floats!' event" by Kulcsos12
• "The Squid Pack" - Eel by Chobittsu
• "Dark blue" by OraMagic

Videos

• Realistic gameplay: "Derp Thunder - War Thunder Gameplay" by BaronVonGamez
• Kingfisher vs. Kingfisher: "War Thunder- OS2U Fight to the DEATH- War Thunder Custom Battle" by PhlyDaily
• Arcade challenge: "War Thunder Planes: The Kingfisher Challenge" by Krebs

Read also

• Text of this page was written for the Wiki competition "Combat training" by Angel_Maker. Link to original contest entry article.
• Ugly Ducklings article by Mark Barber
• Official forum discussion on OS2U-3 Kingfisher

Sources

Paste links to sources and external resources, such as:

• topic on the official game forum;
• page on aircraft encyclopedia;
• other literature.