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You may wonder, in your first days as bona fide mechwarriors, "Do I really NEED double heat sinks (DHS)?" Your answer is, quite emphatically, YES!
At the very least, in light mechs they are an absolute MUST HAVE kind of item.
But then, I'm sure you'va taken the word of a perfect stranger before, only to get burned ("I get tested every month!" or "You're my first, I swear!"). The casinos in the Crimson Strait? NO ONE there is telling the truth.
But I am. I don't expect you to believe me, though, on JUST my word. So, I decided to prove this point to you with some similarly bona fide science. More or less.
This topic came up before, more than a few times. Your best source around these forums for info, of course, is the indispensable user known as Koniving. But really, look at my glorious numbers:
Allow me to explain.
For this test, I used three identically-equipped LCT Locusts. The LCT-1V(P) was equipped with ten single heat sinks (SHS), all torso mounted (2 RT, 1 LT, 7 engine). The LCT-3S was equipped with ten SHS (2 RL, 1 LL, 7 engine). The LCT-3M was equipped with DHS (2 RT, 1 LT, 7 engine). All three mechs were equipped with a 190 XL engine, endo steel internal structure, ZERO armor, and a single CT-mounted large pulse laser (LPL). Each mech weighed-in at 17 tons, according to mech lab. No modules were equipped, and no other equipment not explicitly stated above were equipped. This was done in order to standardize the loadout across the three mechs. While the variant (and the hardpoint layout, therefore) is different for each, this has no known effect on the mech's heat production.
The method for the test follows. Three maps were selected for their geography and ambient heat. Caustic Valley was selected for the high-temperature map. It has the caldera area, in which ambient temperatures are considerably higher than in other map areas, and it has a small lake. Crimson Strait was selected for a moderate-temperature map. It has large areas of varying water depth, as well as considerable land area with consistent temperature. And finally, Alpine Peaks was chose for a cold map. Alpine has no temperature variations, but was chosen over the Frozen City and Frozen City Night maps for its more consistent surface and elevation, and for its relative lack of manmade structures to obstruct movement.
Each mech made a series of test runs on each map, seven in all per mech, for a grand total of 21 test runs. Each run consisted of the following measurements, as the highest percentage number displayed on the mech's HUD:
-heat at a stop
-heat at a walk (~50% max speed; 70-73 kph in the Locusts)
-heat at a run (~100% max speed; 169.3 kph in the Locusts)
-peak heat when firing the LPL from a dead stop with heat normalized to the first measure
On the Caustic Valley map, these runs were conducted in three distinct areas:
-the 3-line, for a nominal temperature measurement
-the lake, for a water-effect measurement
-the caldera, for a max-temperature measurement
On the Crimson Strait map, these runs were conducted in three distinct areas:
-the street, onto which mechs are inserted in Testing Grounds
-the shallow water in the vicinity of the above street
-the deep water behind the island
On the Alpine Peaks map, only one run was conducted. This roughly followed the established path or roads around the perimeter of the map, beginning around the 10-line.
In addition, after completing all other runs on a particular map, the following steps were taken with each mech:
-mech was brought to a standstill and given not less than five (5) seconds for temperature to remain at nominal standstill level
-mech was accelerate to full throttle; simultaneously, LPL was fired continuously
-mech continued running on nominal heat area, over relatively level and smooth surface, until overheat shut down occurred
-time from start to overheat was recorded
Another mech was brought in to test the additional heat for using jump jets for movement. The mech was a JR7-D(S). It was stripped of armor, added the 190 XL engine, added three external DHS (2 RT, 1 LT, 7 engine), added a single LPL in the right arm, and added five jump jets (2 RT, 2 LT, 1 CT). The run was repeated on Caustic Valley in the same manner as with other mechs. The first jump jet (JJ) measurement was attempted from a standstill, resulting in no appreciable change to heat. The next attempt was made while the mech was at full throttle and full speed, again with no appreciable change in heat. The attempt to ascertain a heat difference for JJ use was thus abandoned, and the run was completed in the same manner as with the three LCT mechs.
One other note: The timed-run time entered in the LCT-3M for Alpine Peaks is erroneous. After 4:11, the mech's heat had not yet begun to rise appreciably. With each shot fired, at a full-speed run, the heat would spike to 6%. It would fall back to 0% within about 2 seconds, well before the weapon could fire again. It was decided that it is not reasonably possible to induce overheating under those conditions. However, it is not certain that an entry of "infinity" is reasonable, as it may (however doubtfully) have eventually risen, given enough time. For purposes of this demonstration, it is sufficient to state that the LCT-3M could not be overheated in that time, but was only tested for a period of 251 seconds, during which its heat failed to reach 7% of max, and failed to sustain any appreciable level for the recharge period of a LPL.
Also worthy of note: All three of these mechs are ELITE, and the LCT-3M is MASTER. That is, all heat management efficiencies have been completed by the pilot, and as of a relatively recent patch to MWO, pilots' efficiencies are reflected in Testing Grounds. The following is a set of results from a previous set of tests with the LCT-3S and LCT-3M, equipped similarly (one difference: both had 3 tons of armor, bringing them to max weight of 20 tons):
In this example, the LCT-3M DID overheat and shut down at 4:11.
In the newer test (top), there are three entries with two values. LCT-3S standing on Caustic and Caustic/lake, and LCT-1V(P) standing on Caustic/lake. I was able to reproduce both results, but a pattern to either number was not readily apparent.
So, newblets, what stands out to us so far?
First, the old BattleTech tabletop standard for mounting heat sinks in the legs is present in MWO. That is, any leg-mounted heat sinks in a mech, when that mech's legs are in water, are doubled in effectiveness. They become, for that time, effectively DHS. Since Inner Sphere (IS) DHS are too large to fit in a mech's legs, this effect can only presently be produced with SHS-equipped mechs. The leg-mounted SHS produced a 3% heat difference for the mech standing in water, 3% walking in water, 3% running in water, and 3% standing and firing in water, on Caustic Valley. In the Crimson Strait, the only appreciable heat buildup was at a run and when firing. Running in shallow water, the leg-mounted SHS produced a 3% heat difference, and a 4% difference was appreciated in firing from a standstill.
So, mounting heat sinks in the legs does make them more effective in water-rich environments. The comparison also holds true for torso-deep water. This is a more pronounced difference for the mech with leg-mounted SHS.
That's all neato and stuff, but what about the DHS-equipped mech?
True, the -3M was outperformed by its leg-SHS counterpart in water, at least for standing still and moving. With the exception of the deepest water, though, the DHS mech still reached lower max temperatures when firing from water.
But the DHS mech clearly outperformed the SHS counterparts in most ways. The DHS mech was compared in an overheat run in deep water, also, with the leg-SHS mech. It lasted nearly three minutes of constant running and firing, to the mere 37 seconds of the SHS mech. In Caustic Valley, the DHS mech lasted over three times as long running and firing. In Crimson Strait, on dry land (the route started at the lower level dock, through the train tunnel, around the mountain, and back to the lower level), it lasted more than 4.5 times as long as either SHS mech, and it is virtually infinitely longer-lasting in Alpine Peaks.
Crunch the numbers for yourselves and let me know what you think.
But here's the big-picture tie-in:
In a light mech, you've GOT to keep moving. In most mechs, really, except for snipers and LRM boats in good positions and with good friendly protection, you've got to keep moving. Especially when you're firing, and thus giving up your position, you've got to stay on the move to survive.
But this is absolutely VITAL in a light mech, and most folks spend that cadet bonus on a light, just to get into their first owned mech (there was a time when there was no cadet bonus, and when you accrued ZERO mech XP in trial mechs).
Overheating is death to the light pilot. It is only VERY rarely forgiven by the enemy. You must be able to shoot and move simultaneously, and to do so sometimes for extended periods. There is virtually NO reason at all to take SHS--even on the coldest map, a mech with ten SHS and a single LPL cannot keep running and firing for a single whole minute without overheating, whereas one with DHS can do so indefinitely.
Give up the crit space and the C-Bills. Get the Double Heat Sinks for your mech.
***EDIT 04/11:
IF you don't already know, Double Heat Sinks (DHS) dissipate heat more quickly than do Single HEat Sinks (SHS).
Your mech's engine has a certain number of internal heat sinks that cannot be changed. To ascertain this number, divide your engine's rating by 25 and round down to the nearest integer. For this test, a 190 XL engine was used. 190 / 25 = 7.6 -> 7 internal heat sinks. EVERY mech must have at least 10 heat sinks, however. Thus, three additional heat sinks must be distributed throughout the mech, REGARDLESS of the chassis, tonnage, etc.
Further, each mech can only have EITHER DHS OR SHS installed at a given time. No mech may mix heat sink types. The engine's internal heat sinks will be of the same type as any external heat sinks when installed in that mech. If you pull your 250 STD engine out of your SHD-5M (with DHS) and install it in your SHD-2D (with SHS), the ten internal heat sinks are automatically changed to the type equipped on that mech at no additional charge. Your tech may get sick of having to change out heat sinks every time you feel like trying out a new loadout, but you don't have to pay him for it.
For SHS, the heat dissipation rate is 1.0 whether in or out of the engine. For DHS, the rate is 2.0 in the engine and 1.4 out of the engine. This was a balance decision, as DHS mechs were apparently just TOO ridiculously reliable by comparison to their SHS counterparts.
Also, engines 275 and larger CAN house additional heat sinks inside of them, but the ten built-in internal heat sinks are all that are required. The additional heat sinks are added per the above (1 per every increment of 25 in the engine rating, rounded down to the nearest integer).
Engines do not create more or less heat based on their rating. A 100 STD creates only as much heat as does a 360 XL. What determines your mech's heat is its movement (still, walking, or running) and weapon usage. What counters that heat is your heat sinks and certain consumable modules (Cool Shot). At a fixed movement speed, a mech with a smaller engine will experience more heat than a mech with a larger one, all else being equal. But it is the movement speed relative to that mech's MAXIMUM with that particular engine that determines its heat level.
For background: MWO is the latest step in the evolution of a series of games that began with FASA's BattleTech tabletop (TT) game in the 1980's. In the original game rules, set in the year 3025 (I think?), the heat rules were very similar to what we experience now in MWO.
The map space was divided into equally-sized hexagon-shaped spaces, or hexes. These were 30 meters across. Each mech had a number of Movement Points (MP) that it could spend per round (6 seconds in game time, but often took several minutes to an hour or more IRL, depending on the number of elements on the board), which was determined by dividing the mech's engine rating by its weight and rounding down to the integer. A stock LCT-1V, for instance, had a 160 STD engine, and weighed 20 tons. 160 / 20 = 8 -> 8 MP. This was the mech's walking MP maximum, ie the maximum number of MP it could spend in a round at a walk. Multiply that number by 1.5 and round up to get its max running MP. 8 * 1.5 = 12 -> 12 running MP. Jump jets in TT Battletech cost heat to use, too, and made a target more difficult to hit. As they appear to create NO HEAT AT ALL in MWO, let's forego the JJ discussion.
MWO seems very well based on this MP system basis. At walking speeds (up to 50-60% of maximum speed), a mech generates a walking heat level. At a stop, it generates none (the heat level displayed is due to ambient heat). At speeds above that walking speed, the heat climbs toward a higher running heat level. In TT Battletech, using up to the maximum walking XP caused a mech to accumulate 1 point of heat. Anything over that, up to that mech's maximum running MP, caused 2 points of heat to accumulate. Once all movement and weapons fire was conducted, heat was tallied. Heat was then removed, 1 point per SHS or 2 points per DHS. The resulting residual heat carried into the next round, and any movement or weapons use in that round accumulated on top of the residual heat from the previous.
Each weapon created a certain fixed amount of heat whenever it fired, too. A damaged engine might cause additional heat buildup, too, as could being hit with a Flamer (and later on, certain types of munitions). TT Battletech also had the rule that, if there were heat sinks equipped in a mech's legs, and that mech ended the round in water above its ankle, that those heat sinks' effectiveness would be doubled for that round. Hence the increased cooling efficiency in MWO for heat sinks in a location that is at least partially submerged, at least while it is so. The numbers bear this out for ALL mech components, not just the legs, in MWO--look at the increased cooling efficiency of all three mechs in deep water on Crimson Strait.
Rather than break this out into six-second rounds, though, MWO manages this heat number constantly, in real time. I just thought it kinda important that new players understand the basis for the heat system in the beloved TT game of my childhood.
END OF EDIT***
Edited by TheRAbbi, 11 April 2014 - 09:31 AM.
Sure. You can place DHS, and the never overheat (and have to remove some crits for the 2 required heat sinks(FF armor most likely and a ton of Gauss ammo)), but the benefits would not, for this outliner build, be cost effective, or even effective to the costs in crits it would need to give up to be able to take the upgrade.
