Since we're all sitting here bashing your LHS...in whom you may have faith...it's probably best if one of us delve at least a bit into where angels (and zeeb) fear to tread. *heh* So, without getting TOO far into the physics and mechanics of things, here's a little "thrust angle primer" so to speak.

Let's take any airplane you wish to name. It has a "true center", or 'reference line'...that is to say that, if balanced correctly and trimmed for level flight, it will travel forward directly on that line. it is the 'center of flight' if you will. There are bits of the airplane above, below, and to the sides of this line, but this is the center line of the flight path taken by the airplane. (Yes, the actual definition of the reference line is considerably more complicated than that, but that works for this discussion, so go with me)

Now...everything would be hunky dory if we could mount our motor such that it provides thrust directly along that line. It pulls, in other words, EXACTLY in the direction the airplane wants to fly, imparting no other forces except straight thrust along that line.

However...'tis not to be. SEVERAL things impact its ability to do so, but the 2 most common are "P-Factor" and "Torque"

Torque is pretty simple. The propeller is a rotating mass, spinning in a clockwise direction (usually) from the pilot's point of view. Ok, fine. But, Newton was right...for every action, there's an equal and opposite reaction. So, as the prop rotates clockwise, the airplane tries to rotate counter-clockwise, or roll to the left.

P-Factor is a bit more complicated....in its simplest terms, one side of the prop-disc (the imaginary circular disc created by one rotation of the prop) produces more thrust on one side than the other...the side where the blade is traveling DOWN rather than UP, or, usually, the right side. This means that the motor is basically pulling the plane with more force on the right than the left...introducing a tendency to yaw to the left.

Finally, motors are quite frequently mounted such that the prop's center is not in line with the reference line, due to the shape/size of the cowl, motor, etc...frequently it is above or below it, meaning, again, with respect to the reference line, the airplane gets more thrust from below or above, leading to a tendancy to pitch up or down.

You combine all of these things, and what you get is an airplane that WANTS to fly in a particular direction, but an engine that it attempting to pull it slightly away from that straight line.

Many folks try, thus, to correct this with 'thrust angles'. They mount the motor slightly "tilted" in one way or another (or multiple ways) to offset these issues. For example, to combat P-factor, (that tendency to yaw left), they'll introduce "right thrust"...which i to say, they'll mount the engine pointed very slightly (usually a degree or two) to the right...P-Factor tries to yaw the plane left, but the engine pointed slightly right tries to yaw it right...the hope being that these two effects "cancel each other out". You'll also hear folks talk about "up thrust" or "down thrust" to combat a plane's tendency to pitch one way or another, depending upon motor location.

These attempts to manipulate the motor's physical placement so as to direct its thrust elsewhere are commonly known as "thrust angles". Quite often these days (as is the case with the Pulse XT) ARF manufacturers have (at least in theory) tested their airplanes to determine the 'correct" amount of thrust angle in various directions, and build these angles into the firewall/motor mount. You'll probably notice that the firewall on the Pulse seems to be 'pointing right'...it is.

And yes, depending on the airplane, these angles can certainly have a rather significant impact on how the aircraft flies, so, especially for a newer pilot, it can be pretty important not to change them if the manufacturer has set them. As you can see, however, simply ROTATING the engine can't possible change these angles. Now, if you need to MOVE it to rotate it...say, up, or left, or whatever, then yes, it might...but simply twisting it 90 degrees has no impact on the angles whatsoever.

Now...having said all that, I'll depart a bit from 'common wisdom' and say this:

A growing number of people are starting to realize something Chip Hyde knew a LONG time ago...that ALL of the "variables"...P-Factor, Torque, "Spiral Slipstream", etc etc...that we try to 'correct' with thrust angles are just that...VARIABLES. Torque and P-Factor, for example, are MUCH more pronounced at slow speed, high power, high AoA attitudes than they are at higher speed/lower AoA attitudes. As such, NO "thrust angle" is going to be correct for all situations. it may "exactly" offet a variable at 3/4 throttle, level flight, but then be well off the mark in a high alpha situation, or steep climb from slow speed.

As such, many of us build airplanes with "0-0" angles...in other words, mounted straight ahead, right on, or as close as we can get, to the reference line, with no up or down thrust, and no right or left thrust.

YES, that makes your airplane react to all the "variables"...but the reaction is, in a manner of speaking, "consistent", and thus, at least in the opinion of some (myself included), easier to trim.

Anywho, hope some of that helps. I'm sure it'll be disagreed with by several, but hey, that's half the fun.