Hi Peter:
You and I have not seen eye-to-eye on a few things in the past, but on this subject I tend to agree with most of what you have written. The bias against foam wings by the "purists" happened mostly many years ago when foam wings first came on the scene. Those first commercially available foam wings were not cored out internally, and they were sheeted with very heavy contact type glues. Internal coring, when it came along in the late 1960s, helped a bunch to eliminate unnecessary weight, but there was (and still is...) an inherent build up of excess weight near the tips. That most famous of all CL Stunt articles - written by Bob Gialdini - on the Olympic MK VI highlighted the "barbell" effect and the desirability of light extremities.
The foam wing did eventually earn its "wings" (pun most certainly intended...) in the 1970s, as many who wanted to fly competitive CL Stunt did not possess the skills to build a strong and accurate built-up wing. As virtually everyone here knows, Mike and Arnnie Stott of "Foam Flite" fame and your's truly at Control-line Specialties Co. (later known as Control Specialties Corp.) produced hundreds - if not thousands - of foam cores and sheeted foam wings during that decade. Bob Lampione broke through in 1969 for the first Nats win with a foam-winged model, and some years later in 1976 that crazy hippie kid from New Jersey won a Nats flying a rudderless foam-winged model. (Some would say that then, and even today, that "kid" is still rudderless...). As a data point, Gene Schaffer placed second at that Nats, also with a foam-winged model. At that point I'd venture to say that the majority of the models flown at the Nats had foam wings in them. But, the foam-winged ships did not dominate in terms of wins; the built-up wing in the hands of expert builder/fliers was still the thing to beat.
In the 1980s Jimmy Casale and Paul Walker had many amazing duels at the Nats. Jimmy flew mostly foam-winged models (although he did have a few notable built-up wing ships in that era), and Paul - if I'm not mistaken - also had a few of each. And, Ted Fancher had a few wins with foam-winged models in that decade. The line between the performance of the foam-winged models and the ones with built-up wings was starting to blur. My win at the 1978 World Championships marked the first win at such an event by a foam-winged model, and it would be many years before another one would score the Gold at a WC event. Igor Burger has done it twice in recent years, and Richie Kornmeier has also scored a "popcorn" wing win. (My very good friend, CL Stunt mentor, and Best Man at my wedding, Bill Simons coined the "Popcorn Wing" phrase, and it stuck - at least it did on the East Coast for many years...)
As far as foam-wing kits are concerned, I'm pretty sure that Randy Smith still offers his fine SV line of designs with foam wings. The real problem with a foam wing kit is the size of the box required to ship the wing, and the attendant cost to ship it. The brutal truth is that many CL fliers are not prepared to spend the required bucks to get what they want. This is about the least expensive motor-sport on the planet, and to be successful one must be ready to pay the going rate for top-of-the-line equipment, That means the plane, the powerplant and the finishing materials.
Most also don't know just how much time and effort is required to produce a quality sheeted foam wing. The foam certainly doesn't cost much, but the contest grade balsa can be very expensive. The main reason that foam wings cost what they do is the hours of painstaking work that is required to make a wing that is as light, strong, and accurate as possible. Many times when I quote a price for a sheeted foam wing over the phone, I hear a deafening silence for a few moments. Then a common response is something like, "That's a lot! Hey, it's only a hobby!" It may be a hobby to them, but to me - and to the others who produce these wings - it is part of, if not entirely, our livelihood. Why shouldn't we get just as much per hour of highly skilled work as anyone else? Of course, there are those who fully understand economics and want what they want, and they never complain about the price.
Having written all the above in defense of foam wings, let me close by commenting that a properly built, accurate and strong built-up wing is just as desirable as a foam wing. Different strokes for different folks.
Later - Bob Hunt