Once you've gotten upward in grade and/or rank,, you've probably discovered there are lots of different impulse engines. In this guide, I will set out to demystify and simplify impulse engine. Without further adieu let's get started.
The impulse engines is the equipment on your ship that allows your ships to at sub-light speeds outside of Sector Space. In Sector Space, you are moving faster then light using your Warp Engines. In general, if you loose your Engine Subsystem , you can't move or turn faster than a snail's space. You are a sitting duck ripe for the plucking.
The top speed sublight of your ship depends upon severy factors: the type of ship, the type of engine, the Mark of the Engine and Engine Subsystem Power. Engine power is power setting plus all of the possible bonuses from skills, consoles, traits, and ship class power bonuses. The higher the engine power the faster you can go. Engine power also affect how fast your ship can turn in the same manner.
Your throttle affects how much thrust your impulse engine is generating. It has a linear response. And you can view you ship's current speed by holding the mouse pointer over the throttle bar. The speed (Impulse) will show in real time as a tool tip.
Your ship also has a mode know as Full Impulse. Full Impulse diverts all (actually most) ship's power to the engines. Your other subsystems drop down to 5. The Captain Skill Driver Coil will increase the amount of power your Engine gets at Full Impulse (up to 125). And it improves the reductions to other Subystems (down to 30 instead of 5).
Full Impulse allows your ship to travel much faster in on-Sector Space maps In general, Full Impulse is 2-3x as fast as normal mode, ButFull Impulse can only be used out of combat. When you enter into combat mode, Full Impulse mode is automatically disengaged.
Impulse Engines Types
Note: For this guide I'll use the term "impulse engine(s)" in referring to all engine types. The term "Impulse Engine" (capitalized) will be used for that specific type of engine.
To begin with I'll start with the engine types and well get into more detail later. In broad terms, there are three different types of impulse engines. The differ on their performance curves (i.e. top speed vs engine power setting). In my Beginner's Guide to Ship's Power, I refer to high power as 75+ and low power as <75. In this guide, I'll be use much broader ranges high will be 60+ and low power will be <40. There are three different types of impulse engines: the Impulse Engine, Hyper Impulse Engine, and the Combat Impulse Engine.
Those are the plain vanilla type of engines. The Impulse Engine has a linear performance curve. It's not a curve, it's a straight line. Your new ships come equipped with an Impulse Engine. And there isn't much more to be said about them.
Hyper Impulse Engines
The Hyper Impulse Engine power curve is skewed. It skews upward at higher engine power. And it skews downward at low power settings. So at high power settings is substantially faster then other impulse engines. And at low power settings, it's slow then other engine types.
Combat Impulse Engines
The Combat Impulse Engine power curve is skewed in the opposite manner of the Hyper Impulse Engine. It skews downward at high power settings. And it skews upward at low power settings. So the Combat Impulse Engine is slower at high power levels, and it's faster then other engines at low power levels.
Impulse Engines : The Equipment
In the section, I'm going to discuss the impulse engines as equipment and that means stats. As in all equipment, they have different tiers (e.g. Mk I, Mk II, etc.) The higher the tier, the better the base stats.
Engine have 3 basic stats which affect your ship's movement: Speed (SPD), Turn Rate (TURN), and Full Impulse (FULL). Speed is the base speed the engine gives your ship when it moves. The Turn Rate determines how fast your ship can turn. And Full Impulse is the additional amount of Speed you travel when you activate Full Impulse.
Now as ship equipment, the class of ship that you currently flying has equipment modifiers. These modifiers adjust to the base equipment stat when installed. And when viewing engine equipment, the stats may be adjusted when within the context of your ship (i.e. looking a equipped equipment or items in your inventory). If you are comparing stats in the same context, you won't be getting false numbers. I won't get into details but in general the bigger the ships, the lower the ship speed and turn rate modifiers. The smaller the ship, the higher the engine speed and turn rate modifiers.
Engines, as equipment, also has differing levels of quality (e.g. Common=White, Uncommon=Green, Rare=Blue, Ultra-Rare=Purple). Engines have better quality by having additional attributes. In most cases it will be 1-3 of the following attributes: [SPD], slight increase to the base Speed state; [TURN], a slight increase to the base Turn Rate stat; [FULL], a substantial bonus to Speed at Full Impulse; and [AUX], allows 25% Speed and Turn when engine subsystem is disabled. One extra attribute is Uncommon, two extra attributes is Rare, and three extra attributes is ultra-rare.
What's the right engine for me?
I'm going to give the all purpose answer that everyone hates: It depends. It depends because everyone has their own play style and character builds. There are so many things to consider, there isn't a "one size fits all" answer. But I will give some general advice to help you determine which engine is right for you.
The main factor is the Engine Subsystem power setting which ultimately is your top speed. The power level(s) that you run at will be the biggest determinate for choosing your engine. Since I'm not going to include graphs. here is the next best thing: a chart.
Note: The chart is the top speed at full throttle at different power settings. The stats are for a Light Cruiser (The Federation Starter Ship) and Mk IX Engines. First column is engine power setting, second column is speeds for an Impluse Engine, third column is speeds for a Combat Impulse Engine, and fourth column is speeds for a Hyper Impulse Engine.
In general if your engine power setting run in the low range, a Combat Engine is probably the best choice. Your top speed at lower engine power is quite a bit better then the other two engine types. Some player flying smaller ships may have their engine power allocation at 40-50 because they depend on speed for defense. As you can see from the chart above, the Combat Engine is still a slightly better choice. And at high engine power setting, Hyper Impulse Engines are by far faster.
If you run at the mid power band most of the time, your engine won't make that much difference. The difference in speeds is less then 1 Impulse Factor. So your engine choice isn't that critical. So take into account if you run at lower or higher engine power at times. If its a substantial amount of time, the Hyper or Combat Impulse engine might be for you.
And were does that leave the Impulse Engine? Well it's a middle of the road choice. If you are varying your engine power to all levels of the time, the Impulse Engine is going to be your best choice because of it's linear performance curve.
And now a discussion about extra engine attributes: [SPD], [TURN], [AUX], [FULL]. The [SPD] and [TURN] bonuses are base +1 which will be modified for ship type. If you want a higher Speed or Turning Rate for you ship, look for engines with one or both of these attributes. These bonuses affect the base stat of the ship, other modifiers (e.g. high engine power or RCS Turn Rate consoles) which buff these stats will also boost the bonus as well.
If you hate taking forever traveling around asteroid belts or orbiting planet, engine with the [FULL] attribute. This will boost your top Full Impulse speed by quite a bit. If you get an [FULL]x3 impulse engine, in a Reconnaissance Science Ship or Escort, you can get from here to there in the blink of a Scalosian's eye.
If you are a big PVP player, investing in an engine with the [AUX] attribute is a good idea. When you engine is knocked out by whatever means, your ships speed drops to 5 and your turn rate make's a snail look like a Olympic runner. But if your impulse engine has the [AUX] attribute your can still move and turn at 25% of your base stats. Being able to still maneuver your fragile Escort can be difference between surviving or being turn into an exploding cloud of gas and debris.
And this is the end of the mini-guide. I hope you found it useful. If you learn one new thing you didn't know before, then I have succeeded in my goals for this guide.
After the latest patch a Mark IV Combat Impulse Engine Speed-Turn and a Mark VII Combat Impulse Engine Speed-Turn don't make any difference in combat. None whatsoever. My engine settings are the same, my ship and consoles are the same, my captain skills are the same. Same ship, same captain, same equipment and NO difference in turn rate or speed at the same engine settings. Why? When I view the tool tip of Mark IV and and VII combat engines I see NO difference in stats. Even when I compare the bound engine and the inventory engine. Is this a bug? Thank you.
An important feedback for impulse engines following my older post just above: If the item is level based the whole concept of Mark I-XI falls short. [Edit] I bought the Mark IV from Earth Space Dock paying dilithium. I crafted Mark VII at Memory Alpha. I bought Mark IV when I was Lieutenant Commander. I crafted Mark VII when I was captain. No difference between them. I checked Memory Alpha Mark XI combat impulse engine too. Same stats for me! Weird... Why spend crafting materials for a higher tier item then? Higher tier items' stats improve based on the item mark. Only impulse engines are buggy. There IS a difference between a Mark V Resilient Shield Array and Mark VII Resilient Shield Array at Memory Alpha.
I did notice that SPD and TURN numbers between the different Marks tended very close magnitudes. While trying out various combinations of engines and Ship Tiers and Types, I noticed inconistencies in the reported numbers. For instance, on the Defiant Retrofit, the Impulse and Hyper Impulse Engines were showing a Speed of 14, the Combat Impulse Engine was showing Speed of 13. All 3 engines where common Mk IX engines.
On my Miranda ships, I wound up with a Combat Impulse Engine Mk II. The stats of the Mk II are the same as the Mk IX Combat Impulse engine. Yet the top speed of the Mk IX engine is higher than the Mk II engine.
At this point, I'm inclined to think it may be a display error bug. But I'm going to be doing a lot more testing tonight wide a wide range of Marks of Engines and Ship types. I need a lot more data before I can pinpoint what is going on.