Reviewing IL-2’s P-39L-1

Here we go with my final IL-2: Battle of Kuban aircraft review. Over the course of the last year and half I have reviewed each individual aircraft release as they were presented to us starting with the Bf109G-4 and ending with the P-39L-1. Of course, two more aircraft reviews are due soon as well with the new Collector Plane Bf109G-6 and La-5FN Series 2. Look for those soon. In the meantime… Bell’s unconventional P-39!

A star in the east

The P-39 had incredible potential as a hot performer and Bell aircraft was able to sell the fighter to the USAAF as a new high speed interceptor capable of 360 mph and fitted with some of the most powerful armament available at the time. Operational realities and equipment hamstrung the early P-39s performance and its poor showing in New Guinea while fighting at high altitudes over the Owen Stanley mountain range against the A6M Zero doomed the fighter’s reputation – at least it did in the United States.

The P-39 found little success with the RAF either. Early experiences with the Airacobra Mark I lead the RAF to halt further orders. The remaining Airacobra’s were shipped by convoy to Murmansk in the Soviet Union where new aircraft were desperately needed. Here, the P-39 began to earn a very different reputation.

P-39-greenfields

In 1943, supplies flown in via Alaska continued to increase and multiple units involved in the Kuban battle were equipped with the P-39. Pilots flying it found success against the Bf109 in low altitude fights and famous Soviet aces such as Aleksandr Pokryshkin increased their scores considerably flying the fighter.

Contrary to popular opinion in the West, the P-39 was not used as a “tank buster” in these battles as the P-39s M4 cannon was infrequently (if at all) fitted with AP rounds and the low muzzle velocity of the cannon made for an ineffective anti-tank weapon. Against bombers, attack aircraft and fighters, however, the P-39s armament excelled and the low altitudes on the Eastern Front were just where the P-39 performed best. Having high quality radio equipment also allowed the VVS to use more sophisticated battle tactics such as the ‘Kuban Stairs’ to draw German fighters into battle.

Raw performance

Performance numbers come from the IL-2 forums with tables provided by 1CGS for each of their aircraft. These numbers are a summary. For the full details visit the IL-2 forums.

Stall

P-39L-1

  • Indicated stall speed in flight configuration: 160..172 km/h
  • Indicated stall speed in takeoff/landing configuration: 140..151 km/h

Bf109G-4

  • Indicated stall speed in flight configuration: 165..175 km/h
  • Indicated stall speed in takeoff/landing configuration: 154..167 km/h

Despite the P-39s stability issues, its stall speed is lower than that of the Bf109G-4. Useful for landings but I wouldn’t recommend stall speeds with this fighter as a spin can rapidly develop if you’re not careful.

Climb

P-39L-1

  • Climb rate at sea level: 16.7 m/s
  • Climb rate at 3000 m: 13.5 m/s
  • Climb rate at 6000 m: 7.2 m/s

Bf109G-4

  • Climb rate at sea level: 20.1 m/s
  • Climb rate at 3000 m: 18.9 m/s
  • Climb rate at 6000 m: 15.4 m/s

At sea level the Bf109G-4 does what it does against most fighters and outclimbs the P-39L-1 easily. As the altitude increases the advantage goes more and more towards the Bf109.

Speed

P-39L-1

  • Maximum true air speed at sea level, engine mode – Take-off: 539 km/h
  • Maximum true air speed at 2850 m, engine mode – Take-off: 600 km/h
  • Maximum true air speed at 4600 m, engine mode – Military: 596 km/h

Bf109G-4

  • Maximum true air speed at sea level, engine mode – Emergency: 540 km/h
  • Maximum true air speed at sea level, engine mode – Combat: 517 km/h
  • Maximum true air speed at 2000 m, engine mode – Combat: 564 km/h
  • Maximum true air speed at 7000 m, engine mode – Combat: 640 km/h

At sea level there is very little difference between the P-39 and Bf109G-4 and that narrow performance difference remains in place at medium altitudes too with the P-39 on Take-off power able to outspeed the Bf109G-4 by nearly 40km/h. In actual tests, however, the differences are smaller as the P-39 can overheat quickly and has only 5 minutes on Take-off power.

Turn times

P-39L-1

  • Maximum performance turn at sea level: 21.5 s, at 270 km/h IAS.
  • Maximum performance turn at 3000 m: 30.3 s, at 270 km/h IAS.

Bf109G-4

  • Maximum performance turn at sea level: 21.2 s, at 270 km/h IAS.
  • Maximum performance turn at 3000 m: 27.2 s, at 270 km/h IAS.

Although turn times appear remarkably similar between the Bf109G-4 and P-39 in this test, the ability for the P-39 to dig in and really pull tightly (before stalling) gives it a slight advantage in that a P-39 can easily pull its nose up and get a shot in while the Bf109 may not be able to. This advantage for the P-39 increases as speed increases as the P-39s elevator remains effective.

The P-39 in combat

P-39-overhead-fireball

The best word to describe the P-39 is quirky. It doesn’t follow any of the “rules” for WWII combat aircraft. Its tricycle landing gear, armament, engine arrangement, and cockpit configuration are all unique. The P-39 is surprisingly easy to handle in basic flight and its only on the edge of the envelope do I find it difficult to master.

The aircraft’s weight and engine limits make it difficult for the P-39 to compete in a head to head duel with an excellent aircraft like the Bf109. In more chaotic combat situations, however, sound tactics and experience with the P-39 can make it into a capable performer. Its fast and agile enough to put any FW190 or Bf109 caught out of position in a potentially bad place.

The throttle and engine are sensitive. You need to read the technical notes before flying away with this fighter and you need to watch your manifold pressure, RPM, and throttle position carefully.

The twin .50cal machine guns are more than enough but if you bring the .30 cal wing guns too it makes a heck of an impact to have all of those firing. If those aren’t enough the M4 37mm cannon on the P-39L-1 makes a dramatic impact. If you can land a shot.

As an attacker the P-39 is pretty good too with a 250kg bomb and the previously mentioned weapons making short work of artillery and light vehicles. Its a terrible tank buster (as I explained earlier) so just don’t bother and bring an IL-2 for those tasks. Though effective, the P-39 is not as stable a gun platform as the P-40 (or other types) and I find it a bit difficult to put rounds on target at times and doubly so when there’s a crosswind or turbulence.

In summary, I would say that the P-39 is a useful and effective fighter but it really only achieves that in the hands of a specialist. You need to spend time with the P-39 and really get to know its quirks in handling, armament, and engine management. When doing so you can do really well with this fighter. Caught 1 vs 1 at a disadvantage and I think you’ll want another fighter instead.

Overall report

Pros

  • Very well armed for air to air combat
  • Useful as a light ground attacker
  • Easy to fly (but difficult to master)
  • Tough and able to resist battle damage

Cons

  • Poor climb rate
  • Restrictive engine management
  • Cockpit visibility can be challenging at times

Screenshots

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2 Comments Add yours

  1. TJR says:

    Shammrock, Love your work dude keep it up!

    How do you throttle up to takeoff power mode? is it like boost with a separate button? My throttle (I leave AI engine control on) will only go to 90%

    Liked by 1 person

    1. ShamrockOneFive says:

      With Normal mode you don’t really get much choice. On Expert you can work the prop pitch and throttle to give you Take-off and Maximum (1 minute) power. You can get this on Normal mode but only under specific circumstances.

      In Expert mode the P-39 is a difficult engine to manage. A little easier than the P-40 but not by much and it requires a gentle touch on the throttle otherwise you risk over-reving the engine.

      Like

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