Let's go racing, boyz!
I am very familiar with the principle of operation manual for the 200-4R. It is well worn out.Your statement above that fluid is only one of other means used to cool a clutch pack is incorrect. Its the only way to remove heat from a steel.
The clutch lining holds oil (kind like a sponge) that is used to disperse heat. Sooo if the clutch does not hold enough oil on the shift the heat that was generated will still be present to some degree. This will start to cause the clutches to glaze loosing their ability to retain and release fluid so the clutches ability to disperse heat is now even more reduced. The more the clutch glazes the less fluid is retained the more heat will be generated till the clutch looses its holding capacity and of course it will fail. The thicker steel will help this problem to a degree. It will slow the heating process. Its still the clutches ability to retain a sufficient amount of oil that is the radiator of sorts not the steels alone. Just using a clutch material that will hold more oil will disperse more heat.
I can see where the thin steels in a road race application where shift cycling 2-3 3-2 Etc. can build heat that cannot be removed quick enough before the next shift cycle. In this case thicker steels is much better option. In a drag racing application or typical street application where there is not a lot of shift cycling thinner clutches and steels to increase the capacity can work very well. The drum that Chris is working on would be the best of both worlds.
You're absolutely correct that the fluid removes heat from the frictions and the steels. You're also correct that the fluid in the frictions absorbs and dissipates much of the heat generated during the application of the clutch and after the application of the clutch. I think you are missing the point I tried to make. The fluid removes the heat from the steels after the clutch has applied. The steels absorb some of the heat generated during the application of the clutch. I never stated that the steels were the only means of absorbing or removing heat from the act of the clutch applying. I may not have covered all the ways that heat is absorbed from the act of the clutch applying, and how the heat is removed or dissipated after the clutch has applied, and if that confused you about what I was trying to get across, I apologize.
It appears to me by your statements that you do understand that the steel plates do act as a heat sink to some degree. Right?
Back to the example of the brakes. The rotor absorbs the majority of the actual heat generated during the act of braking. The pads also absorb some heat and the material is sacrificed as it burns away. The act of the pad material burning away into brake dust actually absorbs some of the braking heat. In an automatic transmission clutch, just like quickt explained the friction material is not sacrificed and the fluid is what draws the majority of the heat generated, even to the point that the fluid vaporizes when the heat has reached the vaporization temperature of the fluid. After it has vaporized, the frictions and steels have to absorb the heat being generated and since they're so tiny compared to a true dry clutch design, the frictions and steels burn from being overheated. The steels will do their part to absorb heat from the fluid to keep the fluid from reaching the vaporization temperature. When the steel has heat soaked and can no longer help draw heat from the fluid, and if the duration of the shift is still occurring, heat will quickly reach vaporization temperature and things start going bad.
Back to the brake example. After the brake has been applied and the brake pedal released, air circulating around the rotor will draw heat, that has accumulated in the rotor, away from it. Much like the fluid in an automatic transmission will draw away the heat that has accumulated in the clutch pack. Yes, the fluid did dissipate a lot of the heat during application, but not all of it. The frictions and steels still need some cooling time before the next application of the clutch. As quickt already stated, if the frequency of on-off application is too quick and the pack has not had time to properly cool, the heat will continue to build with each application until the steels can no longer help draw heat from the fluid during application and the fluid, reaching the vaporization temperature much quicker, and before the shift has finish, will vaporize away and leave the clutch to act like a tiny dry clutch. It will burn.
My mission at the start was not to have to explain this in such detail, but I suppose it might have confused some. Sorry for the confusion.
Is there anything else anyone is unclear about?