Cannons just aren't working out for me. (I dumped a relative ton of EC into them and anti-proton damage consoles too... but oh well). But, Escorts are. But Escorts are supposed to use Cannons for max maxiness (I thought) .. so .. this was causing a short circuit.
Arcana beat me to the punch... I was writing about the same thing!
Overall, you should limit a ship to about 5-6 beam/cannon weapons in total (even if you have more slots to add additional weapons) at 100 weapons power level for energy (I typically set 80-100 weapons, 60 shields, 40 engines, and 20 aux... you have the presets to punch up shields or engines if you need it).
Also, the types of weapons in use will drain your energy faster than others:
Dual Heavy Cannons are the worst to place. While their Damage Per Volley/DPS is high, they drain -12 power each. (There are wide arc varieties you can craft, but those have the same drain.) I'd use one at most.
Quad Cannons are an odd beast. Power drain is -10 each, four shots, but you can only equip one quad cannon per ship and there's three types: Disruptor, Phaser, and Plasma only. (I've never used them: they are levelless, and damage per volley is 50% of a Dual Heavy Cannon, or essentially the same output as a Dual Cannon.)
Dual Cannons and
Single Cannons (just called "cannons": Plasma Cannon, Tetryon Cannon, etc.) drain -10 power each.
Beam Banks are the beam array version of cannons: narrow arc, two shots per fire. Like cannons, Beam Banks also must be front mounted. Like Beam Arrays, though, proximity is required for higher damage: firing these at 3km is better for damage than at 9-10km, which is why die-hard escort players tend to pass on these in favor of cannons. (Like Blasters in CoH, Escorts shouldn't be close and personal with anything unless it's trying to fly right past it.) Those drain -10 power each.
Turrets are the weakest of the cannon weapons, but they are worth consideration for your back slots over mines or phaser banks because their radius is 360 degrees. They constantly fire no matter what direction your ship is headed at: if you're facing forward, they can fire at the same time as your front weapons. If you don't use turrets on the back slots, those weapons can't fire unless you turn around. These drain -8 power each.
Better Weapon Info:
http://sto.gamepedia.com/Ship_weaponWhy not Beam Arrays? Beam Arrays and other high-arc/wide arc weapons are more useful on Cruisers and Science vessels where broadsiding a ship matters: Escorts fly and turn way too fast to make broadside attacks worth the trouble, and Cruisers have way more slots to make the lower DPS of Arrays not matter as much. The higher flight speed and faster turning potential means I avoid wide arc weapons on Escorts typically: the port and starboard shield facings are better used to bend a 90 degree turn if your front and rear facings are zeroed out and you need quick defense from fore and aft targets.
Cannons do the same damage from 10Km away as they do from point blank. Of course, your weapons energy available means your first volley of cannon fire will be the most damaging with repeat volleys being less and less powerful until the energy recovers. With Beam Arrays and Beam Banks, you have both Weapons Energy Level as well as distance mitigating damage potential.
And like any glass cannon, you should go out of your own way to get out of a position where you take fire on all four sides in an Escort. That's the best way to explode.
So an
ideal weapon mix for DPS play is about 5-6 weapons to drain about 50-60% weapons power in a single volley facing forward in attack, with the "recovery phase" being when you are flying away from your target taking fire in the aft and positioning for another run at them. Your turrets can't fire fast enough to drain your recovering weapons energy without the front weapons engaged. The downside to this approach means that having them means you'll be 8-16% less in energy than the first volley unless you cease fire altogether when retreating. (This guide was written for a Science ship, but it works on Escorts, too. Escorts are just squishier and typically can't do control worth a damn.)
Yes, Torpedos are free: don't worry about them draining energy. Torpedos make excellent additional weapons if you have more slots than you need for beams and cannons. Mix the front slots with any combination of Cannons you like, with one slot for a torpedo, and the back slots with turrets and a one slot torpedo:
Typical Tier 5/6 Escort --
Front (5 slots): 2 slots of Dual Cannons or Cannons, One Dual Heavy Cannon, One or Two Torpedos (one cluster, one standard as a fallback since recharge on cluster torpedos sucks.)
Rear (3 slots): 2 slots of Turrets, One Cluster Torpedo
The Breen Arc is the best way to get your first cluster torpedo. Typically, you can only equip one TYPE on a ship, so the Delta Quadrant Missions are a place to pick up a second one. (I'm not 100% sure of the names, but you can't have two Breen Cluster Torpedos on the same ship. You can, however, have one Breen and one Vaadwaur Cluster Torpedo.) I like Clusters on Escorts because they turn the mine concept around on it's head: instead of dropping them and passively hoping a pursuer hits them, you're throwing them at a shield weakness directly to exploit it. The downside of Cluster Torpedos are the same as using mines: they're practically useless on a small, fast craft like an Escort (or enemy equivalents like Fighters or Corsairs). When the cluster unpacks into mines, 75% of the time an escort is too far away from the mines to trigger them, or they lock on but can't move fast enough to catch the ship and eventually fade. Having a regular torpedo on hand mitigates this problem (a quantum overcomes speed issues readily.)
Hargh'peng Torpedoes are also sweet if you can nab one early on in the game. If you do get one in the early levels, don't ditch it! The crafting system means that a Mark III Hargh'peng can be upgraded to a Mark XIII and placed on your Tier 5/6 ship no problem instead of paying a ridiculous fee for one in the Exchange. Especially on large ships, it's entertaining to watch it slap a Borg Cube with a purple Radiation DOT, followed by a secondary explosion that hits up to 10 ships in an AoE from the target. (The consequence? Hargh'peng Torpedoes can't be improved with consoles, take longer to recharge, and Torpedo Skills like High Yield doesn't affect it.)
And I'd set all the cannons/beams/turrets to autofire (right click them to outline them as green), so it's as easy as picking a target, flying up to them, then for the distance from 10-2km, watch your front shield and the enemy facing, and click on a torpedo if the enemy facing goes down. If it doesn't, fly away, heal your front shield facing (or balance the remaining shield energy at the least), and come back for another go at it.
Arcana is right, every shot fired makes your next shot less powerful until your weapons energy is recovered. But at least this way you're constantly firing and not worrying about running "dry" on subsequent runs. (Starting a run at below 50 weapons power is no place to be.)
Also: my captain is an Engineer. "Miracle Worker" alone improves the survivability of an Escort dramatically when fighting something much more powerful than you, or a mob of 2-4 ships that are your level or close, but it's not a strategy that can keep an Escort alive in a mosh pit of 4-8 ships firing upon you at once.
(I'm an armchair player, not a min-maxer. Corrections welcomed!)