SM.91
Contents
Description
During 1942, the Regia Aeronautica required a defence fighter to provide a defence against bombers accelerating the advance of Allied troops into Italy. The SM.91 was created, a twin-engine fighter with DB 601 engines, armed with six 20 mm MG 151s up front and a turret equipped with a 20 mm MG 151 controlled by the gunner. 2 were created, taking flight for the first time on 11 May 1943, and achieved 27 hours of flight time but never entered official evaluations. One was captured by the Germans, while the other was destroyed by Allied bombing raids.
Introduced in Update 1.85 "Supersonic", the SM.91 looks like a normal heavy fighter with a very good frontal armament capable of destroying an enemy aircraft or a light or medium tank very easily with a single burst, however the performance of the aircraft allows it to recover quickly enough when it loses a lot of speed, unlike other heavy fighters. In addition to this, it equips a small rear turret with a 20 mm cannon with which you can easily defend yourself from enemy fighters.
General info
Dimensions and weight
Length: 13.25 meters
Wingspan: 19.70 meters
Height: 3.85 meters
Wing area: 41.76 sq.m
Empty weight: 7023 kg
Plug-in capacity: 600 kg
Maximum practical weight: 8653 kg
Theoretical wing load: 168.18~207.21 kg/m²
Crew: 2 people
Power configuration
Number of engines: 2 units
Engine Country of Origin: Germany
Engine brand: Daimler Mercedes-Benz
Engine type: 12-cylinder tandem (V12) liquid-cooled piston engine
Engine Model: DB605A1
Pressurization configuration: No pressurization system
Engine weight: 720 kg
Idle power: 5 hp
Sea level static power: 1236 horsepower (285.68~351.99 horsepower/ton)
Sea level afterburner power: 1407 horsepower (325.21~400.68 horsepower/ton)
Static power of 2 kilometers: 1320 horsepower (305.10~375.91 horsepower/ton)
5,000 meters static power: 1257 horsepower (290.54~357.97 horsepower/ton)
8 km static power: 1081 horsepower (249.86~307.85 horsepower/ton)
Take-off and landing performance and ground maneuverability
Take-off and run distance: 640 meters
Landing and running distance: 520 meters
Speed of damage to the landing gear: 300 km / h
Minimum take-off speed: 166 km / h
Landing gear layout: the last three points
Landing Gear Type: Full wheels
Gliding turning radius: 12.52 m
Parking elevation angle: 13.0 degrees
Endurance
Fuel tank distribution: 1 on each side of the wing (inside the engine compartment), 1 on each side of the fuselage (behind the engine), and 3 on each side of the wing (outside the engine compartment).
Internal oil volume: 309~1030 kg
Maximum static fuel consumption: 9.90 kg/min (4.95 kg/min per unit)
Battery life: 31 minutes 13 seconds ~ 104 minutes 03 seconds
Theoretical range: 1612 km
Combat radius: 480 km
Structural strength
Critical speed of disintegration: 845 km/h
Aileron rudder criticality: 280 km/h
Elevator lock rudder critical: 450 km/h
Steering rudder lock rudder criticality: 200 km/h
Flap gears: Off-Operational-Takeoff-Landing
Flap damage speed in each gear (excluding closed gear): 535-450-260 km/h
Flight performance
The SM.91 fulfils a similar role to the P-38 when flown as an interceptor: a twin-engined fighter that is surprisingly capable as a dogfighter due to its good turn rate, especially when spaded. The twin Piaggio P.XI RC.40 12 cylinder inline engines, which happen to be a pair of the powerful DB 605 Inverted V12 engines, are placed away from the cockpit, meaning its hard to take them out in a head-on. However, the heavy nature of the plane means that its acceleration is quite sluggish at low altitudes. The aircraft also sports leading edge wing slats that shorten the turning circle and has airbrakes that can help it slow down in a dive and help when landing on an airfield, which is already fairly easy due to its tri landing gear.
| Characteristics | Max Speed (km/h at 7,010 m) |
Max altitude (metres) |
Turn time (seconds) |
Rate of climb (metres/second) |
Take-off run (metres) | |||
|---|---|---|---|---|---|---|---|---|
| AB | RB | AB | RB | AB | RB | |||
| Stock | 561 | 546 | 9500 | 21.1 | 21.9 | 9.3 | 9.3 | 300 |
| Upgraded | 610 | 585 | 19.0 | 20.0 | 15.3 | 12.0 | ||
Details
| Features | ||||
|---|---|---|---|---|
| Combat flaps | Take-off flaps | Landing flaps | Air brakes | Arrestor gear |
| ✓ | ✓ | ✓ | ✓ | X |
| Limits | ||||||
|---|---|---|---|---|---|---|
| Wings (km/h) | Gear (km/h) | Flaps (km/h) | Max Static G | |||
| Combat | Take-off | Landing | + | - | ||
| 845 | 300 | 535 | 450 | 260 | ~10 | ~5 |
| Optimal velocities (km/h) | |||
|---|---|---|---|
| Ailerons | Rudder | Elevators | Radiator |
| < 280 | < 200 | < 450 | > 380 |
| Compressor (RB/SB) | ||
|---|---|---|
| Setting 1 | ||
| Optimal altitude | 100% Engine power | WEP Engine power |
| 5,800 m | 1,232 hp | 1,387 hp |
Survivability and armour
- No armour
- Self-sealing fuel tanks (1 in each centre wing, 1 in each frontal section of tail, 3 in each wing)
The SM.91 has a good survivability, being able to take multiple 12.7 mm hits before going down; however, be careful when the enemy has 20 mm cannons or higher since they will cause serious damage to your aircraft fuselage and engines.
One DB 605 Inverted V12 engine is powerful enough to keep the aircraft flying in case of losing the other one, however; use of Manual Engine Controls is vital in this situation. Detailed explanation below.
Modifications and economy
| Flight performance | Survivability | Weaponry | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
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Armaments
Offensive armament
The SM.91 is armed with:
- 3 x 20 mm MG 151/20 cannons, nose-mounted (300 rpg = 900 total)
- 1 x 20 mm MG 151/20 cannons, chin-mounted (300 rpg)
- 2 x 20 mm MG 151/20 cannons, wing-mounted (300 rpg = 600 total)
The SM.91 has 6 of the powerful MG 151/20s mounted in the centre of the aircraft and can utilise the minengeschoss round. Use "Stealth" or "Air targets" belts for best effectiveness.
Suspended armament
The SM.91 can be outfitted with the following ordnance:
- Without load
- 6 x 50 kg GP 50 bombs (300 kg total)
- 6 x 100 kg GP 100 bombs (600 kg total)
The SM.91 can carry up to 6 x 100 kg bombs, which makes it useable in ground forces battles. Due to the rather small size of the bombs, you have to be extra accurate when dropping bombs.
Defensive armament
The SM.91 is defended by:
- 1 x 20 mm MG 151/20 cannon, dorsal turret (350 rpg)
The SM.91 can defend itself very well from any tailing aircraft. Use "Universal" belts for the most effective defensive fire.
Usage in battles
When flying it as an interceptor, it can shred bombers apart with its powerful armament and can ward off escorts who try to tail it with its single 20 mm cannon. However, it is paramount that you come in from oblique angles when attacking bombers, as their gunners can easily take out your pilot due to your lack of armour and bulletproof glass.
When flying it as a ground attacker, be wary that carrying the max payload will significantly decrease performance and you will be a prime target for low flying fighters like Yaks and Spitfires. However the maximum payload is rather weak, only 6 x 100 kg bombs with a max armour penetration value of 91 mm and a blast radius of 4 m. This means that you must land a near perfect or direct hit on medium and heavy tanks in order to destroy them.
On Simulation Mode
While flying on simulation mode you can take your time to reach a safe altitude around 3,500 to 5,000 m climbing within ally air space. Keep in mind that you should use this aircraft with a Boom and Run mindset, that being the case, you should dive on your target while remaining hidden for your enemy as long as possible. Remember that in order to concentrate your burst mass in one zone, and hence having a greater chance to destroy the enemy plane (module; i.e., wings, tail) in one pass, you should open fire according to the gun targeting distance you are using, being a good setup from 300 m to 500 m.
With your 6 x 20 mm MG 151/20 cannons you will be able to shoot down almost every enemy aircraft on your gunsight. However, always check the surroundings before attacking, you dont want to get swarmed after engaging with an enemy. You have to remember that most enemy aircraft, save bombers, are faster and turn better than you. Therefore, you need to choose your targets wisely.
If everything mentioned before goes wrong and you end up with an enemy, or in the worst case, multiple of them going after you, you still have one chance to get out of that situation alive and it is your dorsal turret. The plane is equipped with a 20 mm MG 151/20 cannon and, when used correctly, it can pose a serious threat to most enemy fighters tailing you.
It is recommended to perform evasive manoeuvres and wait until the enemy behind you gets in a range of <500 m, practically point blank. Therefore you will have an easier time leading your bullets in the enemy direction; when successfully hitting an enemy at this range it will just take a couple of direct hits to set the bandit on fire, or if you get a good shot at his wings, send him down immediately.
Counter-tactics
Do not head-on this plane, the 6 x 20 mm cannons will most likely destroy your plane and do not underestimate the defensive cannon. Armed with minengeschoß belts, the nose-mounted cannons can easily cut your wings or set you on fire.
It is best to attack this plane from below since the deffensive 20 mm MG 151/20 cannon won't be able to aim lower than just a few degrees below the tail. Keep also in mind that even a P-47 can outturn it, so if an SM.91 gets behind you, force him to turn and make it lose energy.
If you are flying an aircraft with decent performance in vertical manoeuvres, force the SM.91 to fight on the vertical. Due to the deficient acceleration capacity combined with a bad performance when going vertical, you will most likely get guns on target rather easily with this tactic.
Manual Engine Control
| MEC elements | ||||||
|---|---|---|---|---|---|---|
| Mixer | Pitch | Radiator | Supercharger | Turbocharger | ||
| Oil | Water | Type | ||||
| Not controllable | Controllable Not auto controlled |
Controllable Not auto controlled |
Controllable Not auto controlled |
Separate | Not controllable 1 gear |
Not controllable |
The SM.91 has a very forgiving MEC, therefore don't worry about killing your engine and try different settings according to the maps conditions.
As a general setting you can: set the water and oil radiator at 30%, it will be a long time before cooling off is needed if using 100% throttle, however if WEP is engaged then you will need to open both radiators up to 45%; propeller pitch set at 100% when climbing and lower it to 85%-90% when going horizontal.
If the engines take damage, it will usually be only one of them. That said, the SM.91 is able to fly with only one of its engines working. However, try to extend its life span or even keep the engine alive until you are back at the airfield to repair.
In order to do this, set the damaged engine (or both, if that's the case) as follows: water and oil radiator at a 100%, propeller pitch at 0% to 30% depending if you really need a boost to, for example, get over a hill; and throttle to 50%.
Pros and cons
Pros:
- Devastating armament: 6 x centre-mounted 20 mm MG 151 cannons will make quick work of any aircraft
- Great for head-ons
- Main armament has a large ammo capacity
- Gets an attacker spawn (AB/RB)
- 20 mm MG 151 cannon in the back turret
- Surprisingly good turn rate
- Can act as a powerful interceptor
- Made entirely out of metal, so it can take some punishment.
- Fuel tanks are self-sealing
Cons:
- Tail is prone to snapping when under fire
- No armour protection
- Big target
- Lack of bulletproof glass means pilot is susceptible to getting knocked out, especially in head-ons
- Wings are littered with fuel tanks
- Carrying the largest payload has a noticeable effect on performance
- High tendency to flip forwards upon landing when braking
Summary
This type of aircraft was developed by Savoia Masetti in the early 40s of the 20th century, which has relatively fierce firepower, with the overall ideal flight performance, the aircraft can be competent as a heavy fighter mission, and at the same time its acceptable mount and cannon firepower combined, in the ground support also has a completely standard efficiency, the only defect is that the whole aircraft has no effective protective measures, survivability is difficult to meet the needs of fighting in the dense self-defense firepower network. In terms of appearance, the overall configuration of the aircraft is similar to that of the P-38 series of heavy fighters, with the central fuselage mainly housed the cockpit, while the engine nacelles on both sides extend backwards and install tails, but it is more slender and slender than the P-38 overall, and a larger self-defense turret is installed in the rear of the central fuselage.
History
In 1942, the Regia Aeronautica requested a new, long range aircraft that was to be powered by the German DB 601 Inline Inverted V12, carry an 800 kg bomb load, have 6 x 20 mm main armament and a single 20 mm rear cannon. Savoia-Marchetti had previously worked on the SM.88 heavy fighter and the request for a long range fighter disqualified the 88, as it only had a 1,250 L fuel capacity. SM started to work on a new fighter named the SM.91 that was made entirely out of metal, had 6 x 20 mm MG 151 cannons (7 if you count the rear gunner) provided by Germany, was powered by two DB 605 engines and had a range of 1,600 km with a 1,600 L fuel capacity that could be enlarged to 1,800 L with auxiliary tanks.
The two prototypes that were produced made their maiden flight on the 11th of May, 1943 and logged 27 hours at Vergiate. However, it was never entered into the official trials, mainly due to it still being in testing. The first prototype was captured and sent to Germany, and the second prototype was presumed to have been destroyed by bombers.
Media
- Skins
- Videos
See also
External links
| Savoia-Marchetti | |
|---|---|
| Bombers | S.M.79 serie 1 · S.M.79 serie 8 · S.M.79 AS · S.M.79 bis/T.M |
| S.81 | |
| Attackers | SM.91 · SM.92 |
| Export | S.M.79 B |
| Captured | ▀S.M.79 serie 1 · ▀S.M.79 serie 4 · ▀S.M.79 serie 8 |
| ▀S.M.79 AS · ▀S.M.79 bis/N · ▀S.M.79 bis/T.M · ▀S.M.79 B | |
| Italy strike aircraft | |
|---|---|
| Ba.65 (K.14) L · Breda 88 (P.XI) · F.C.20 Bis · P.108A serie 2 | |
| Ro.57 Quadriarma · SM.91 · SM.92 | |
| Hungary | ◐Bf 110 G-4 · ◔IL-10 |
| Romania | Hs 129 B-2 (Romania) |
