The most significant factor in this issue is scale. The simple term that is used in the engineering work is called k/C, or a non-dimensional roughness parameter. "K" is the measured height, perpendicular to the airfoil surface, of the ice shape. "C" is the chord length. This term is has a major role in the aerodynamics of the contaminated wing.
Any given icing environment will yield a range of ice shape dimensions and features. However, it is more or less intuitive that a C-5 passing through Cloud X will encounter the same droplet size, liquid water content and droplet distribution that a Citation will encounter in Cloud X. The C-5 will accrete quite a bit more mass, due to the area swept by the wing, but the nature of the ice shape is unlikely to be greater in measured height than the shape found on the Citation.
Therefore, the "k" term will be somewhat comparable, for the sake of the argument at least. There are other factors at play, but they can be set aside for the moment. If the "k" term is the same, but the "C' term is so radically different...well, you get the idea. The k/C ration for the Citation is much, much larger than the k/C for the C-5.
The C-5 will also push a lot more droplets just plain out of the way, due to the wing size and the pressure wave ahead of it. Smaller airfoils arrive at the cloud with less "warning" to the droplets, and more are accreted. This is why the tail often ices when the wing doesn't.
Thus, no C-5's or 747's dropping out of the sky. Those of us in this part of the business have contemplated for years the possibility of an engineering standard reflecting scale, but we just don't know enough to really define one. Instead, the manufacturer works this out on a case-by-case basis. Airbus knew they wouldn't need much protection, so they designed accordingly and were easily able to certificate that design.
Unfortunately, many, many pilots live under the impression that their airplane can "handle" a lot of ice. As I have said in other threads, this is truly a myth. Trunov and others showed as far back as the seventies that only a few thousandths of an inch of roughness was required for substantial degradations. Douglas pointed this out in their many ground deicing cases as well...look up the work done by Ralph Brumby. In the icing accident database that I maintain for the FAA, the average ice accretion either found afterward or reported by the pilot is between one quarter and one half inch. Often, one eighth is sufficient...particularly for the Citation, by the way.
The problem is, you can't identify the critical parameters, such as horn angle, horn height, roughness, etc. from the cockpit. And you have no idea how close to the modified Cl max you are at any point. The only real solution is to get rid of the ice...which is where good, hot, thermal systems work best.
Regarding tailplane stall events in jet aircraft: there have been no accidents that I am aware of. However, as I indicated previously, the DC9/MD80 design, which includes the 717, is susceptible to the ice contaminated tailplane stall problem. For reference, go to the NASA ASRS website and look up this report: 392928. This is the only published report of such an incident, but I am aware of two others anecdotally.
You are correct in the statement that the stabilizer is generally a thinner airfoil and thus more efficient at ice accretion. The idea that Boeing and Airbus have applied is to design the stabilizer so that its normal operating envelope is well below Cl max. Therefore it can tolerate a significant degree of degradation in Cl max, due to ice accretion, before any problems arise. This appears to have been rather successful since no events have been reported. The certification is typically done with a three inch ice shape modeled on either analytical or wind tunnel data.
With regard to the question of whether large aircraft need the use of airfoil anti-ice/de-ice, I would recommend a very conservative approach. As I stated in an earlier post, scale plays a significant role in the relative degradations experienced in icing. That said, airfoil ice will most definitely shallow the aerodynamic margins. As the pilot, you have absolutely no tools with which to measure or assess that degradation. One of the more insidious characteristics of icing degradations is that, for many airfoils, the Cl curve with ice lies extremely close to that without...until Cl max is attained, at which point the wing's behavior can become "non-linear", which is another way to say you go off a cliff.
During the years that I have worked with this topic, I have become concerned that the large jet icing accident, were it to occur, would take place during a maneuver that required a significant bit of the margins built into the normal operating envelope. The one that always comes to my mind is the go-around from a low altitude. In fact, in 1989, a Canadian DC-8 experienced a pod strike and landed off the side of the runway at Edmonton following a low visibility ILS approach in freezing drizzle. Despite noting ice accretion, the captain had declined operation of the airfoil ice protection system. The investigation was unable to determine whether a stall had taken place, but noted that the approximately one inch of rough ice on the wing may well have precluded a successful go-around once the approach stability was lost at around 100 feet.
In March of 1996, a Canadian Airlines 767 experienced a tail strike at Halifax. There were a number of reasons for this, but one aspect was a performance degradation noted in the DFDR data beginning at around 400 feet. The investigation was unable to explain this, but considered that ice accretion may have been the cause of the degradation. Again, the crew had not operated the airfoil ice protection, again in a freezing drizzle condition. In this case, they did not see any ice on the wipers, etc.
In 1997, an A300 experienced a roll upset while entering holding near Miami. Ice accretion was considered to be one possible explanation, as the upset could not be duplicated in a simulator.
The use of of the wiper nut and such other indicators is a bit problematic. Several years ago, departing Milan in a 767-300, we heard an ATR issue a PIREP of severe icing (this was well after the ATR debacle). I became very attentive, as I wanted to see just how this would manifest itself. We saw nothing on the wipers or windshield area. However, the relief pilot stepped back and examined the wing leading edge. He reported about three quarters of an inch of very rough ice on the protected surfaces of the wing. Several minutes later, and after we had actuated the wing anti-ice, we finally noted a very small and clear ice accretion on the wiper. At night I don't think we ever would have seen it.
The simple fact is that, unless you're in a 727 trying to get above FL310, there is little reason NOT to use the wing ice protection.
I'm not sure I see the connection between your 737 event of forty some years ago and ice contaminated tailplane stall. It sounds to me more like a regular old contaminated wing stall, although I'd sure be interested in more details. Along those lines, there have been a couple of good ASRS reports involving 737s. Look up these NASA ASRS report numbers: 426216 and 815450. In the first case, I know the captain who wrote it and I have seen his pictures. He wasn't exaggerating.
There is no evidence that laminar flow airfoils will naturally avoid ice accretion. Laminar flow is a pretty fickle thing to maintain in the real world, what with dents, dings, bugs and such, but there have been a bunch of wind tunnel studies done with some laminar airfoils, particularly the NLF414. This airfoil may have a better behavior with ice than some of the classics, but not nearly enough is known to make concrete statements. In any event, it accretes the ice just fine.
Although they're usually happy to discuss it if you find the right person.
