ENERGY MANAGEMENT

The information on the chart above is of no value unless you can make it work for you. But what exactly does it tell you to do? You might look at the chart above and see the corner speed at 380kts and go all misty-eyed thinking that you just need to stay at corner, turn at your maximum rate, and good things will happen. Unfortunately life isn't that simple!

The red curve on the EM diagram represents your instantaneous turn rate. The highest point on that curve is well known to flight sim' pilots as the corner velocity and it is easy to see how the turn rate at that point makes it very attractive. Unfortunately you simply will not be able to stay at that point without out losing energy very rapidly. For example, at 400kts in the above diagram you will have a negative excess power of around 1250 feet per second.

That means that if you want to stay at that speed, pulling 12.2G you will need to trade in your altitude at a rate of 1250ft every second. That's the catch, the price is simply impossible to pay! You can't lose altitude that quickly because 1250 ft/s is over 700kts and you are only at 400kts. Even if it were possible to lose altitude at that rate, placing yourself 6000ft below an opponent is tactically unsound.

So in order to answer the question, we need to reflect on something known as energy management. Energy management is difficult to explain because while turn rate is easy to see in flight, it's a solid concept that most flight sim' pilots find easy to visualise, energy is much more difficult to grasp. That's why inexperienced pilots take the turn rate now, and worry about the energy later. That's a mistake that can be illustrated with an example.

Starting at an altitude of 10,000ft with a clean configuration at 400kts, execute a break turn by banking and pulling full aft stick and maintain it for five seconds. What will happen is shown in the diagram below. If you hold your altitude during that five seconds your speed will bleed from 400kts to 200kts, because with a negative Ps of 1250ft/s you will decelerate at a rate of 38 knots every second. That situation is shown in the diagram below.

So far we have considered two possibilities. Firstly we considered trying to trade altitude to maintain airspeed, but we would need to lose around 6000ft, which we know is impossible. The second alternative was to allow our speed to bleed at the rate of 38kts every second. However there is a third option, you could maintain your speed by using less back pressure on the stick, and maintain just that G load that will allow you to keep your speed constant! That is the correct option!

That's the hard part to grasp, most pilots won't ease the backpressure for fear of being out turned. They can't believe that maintaining their energy could be as important as maintaining their turn rate because the effect of turn rate is so much easier to see. And few of us would deny that the sight of a bandit gaining angles is enough to inspire an urge to pull harder on the stick. But let's see what happens if we do pull less G and maintain our energy, that means maintaining both our 10,000ft altitude and our 400kts airspeed.

Here you see that by sustaining your 400kts you have given up sixty degrees to the pilot who pulled full aft stick. However, if he elected to stay co-alt he will now be at 200kts and will suddenly realise that those angles were only on loan. Had he elected to trade some altitude to help mitigate his loss in airspeed, he would still be both lower and slower, faced with the prospect of losing his angles and his airspeed to get the altitude back.

You, on the other hand, have only been using your energy at the same rate at which your turbofans have been producing it, you will therefore be able to continue to turn at your sustained turn rate indefinitely. Your opponent has sacrificed his energy permanently because that extra turn rate required a big energy overhead that was non-refundable! It's easy to see in this example that being low or slow is a bad thing.

Generally speaking, spending all of your energy for a gain that does not prove decisive is unwise. It is better to save that energy for when you really need it, an emergency, or a sure kill. It is better to make small gains and retain the energy even if faced with the prospect of a shot. However if you are as close to getting a kill as shown in the screen shot below… Take it.

In this screen shot you can see the pilot holding a sustained turn at just over 300kts at 4.8G while holding the Bandit in the funnel. You see that the last extra pull for lead and the shot cause another 40kts to bleed away, and this is an extremely vulnerable position to be in. If the bandit had a wingman, or if the fight had attracted other enemy aircraft, 260kts is not a good place to be! Regardless of how good your situational awareness may be, dogfights have a tendancy to attract other aircraft like mothes to a flame, while any degree of target fixation will ensure that you remain unaware of your peril. Your only safe guard in this, is training. You must develop the habit of never geting slow with out very good cause.

The prospect of a kill, may have justified the shot above, however don't be like the pilot in the previous example who used all of his energy to gain 60 degrees, with a further 60 yet to go, it wasn't worth it. Wallowing at 200kts with poor control and a bandit pulling away from you is not going to give you the sort of shot that will compensate you for the energy loss. What is worse, your opponent will own the vertical, because when he recognises your low Es he will be able to make use of the vertical and win back those angles and more, since you will be unable to follow him.

Only spend all of your energy if you are sure of a kill or your life depends on it! If you detect a missile launch, or a bandit making weapons parameters, then spend it all. There are no prizes for dying with an extra 100kts on board. However if you are tempted to spend all of your energy just for a better position, remember that even with the prospect of a shot, it may only be a worthwhile risk in a clear one versus one environment. Once your energy is gone it's not easy to get back, and another bandit or a missile launch warning while you have low Es will spoil your day.

The point of this example is simply that when the pilot in the above example used G for brains and thought he was winning the angles fight, he was actually losing an energy fight he didn't even know he was in, the old rope-a-dope in action! Referring to the next and last EM diagram then, we are now in a position to state what it is really telling us. Basically, don't take the turn rate now, and worry about the energy later. Hold your energy, fly intelligent BFM and the angles will take care of themselves!

So to recap, if you try to fly the red line with full aft stick, you will gain angles for a short time, but your speed or altitude will be consumed so quickly that your ability to continue turning will ebb with your energy. You will become low or slow with no where to go! Think of the red line as being an indication of where you could go in an emergency! A wise opponent, who flies closer to the blue line and his sustained turn rate, will maintain his energy and thus retain the ability to continue turning indefinitely.

So, the answer to the original question is that the diagram shows you to fly to the blue line! Stay in that part of the envelope where you have positive or zero Ps, try and stay out of the negative Ps region when ever possible.

Go to Part IV