Azért ezek az alaktényező dolgok csalókák ám és olyan tényezők befolyásolják, melyeket ránézésre nem lehet csak úgy megállapítani a formából.
Ez egy annyira soktényezős egyenlet, hogy nagyon el lehet veszni benne.
A gép pillanatnyi állásszöge, a különféle szerkezeti elemek interferencia ellenállása, a pilonok, fegyverzet hullámellenállása és azok interferenciái és még sorolhatnám.
Az alaktényező ráadásul nem a légellenállás maga, hanem csak egy faktor.
A tényleges légellenállás az, amivel a hajtóművek tolóerejének mindig is ellent kell tartani.
Csak, hogy pár komolyabb ellentmondást is hozzak példaként, az F-15 alaktényezője jobb, mint az F-4-es Phantom-é vagy a kis F-16-osé, de a teljes légellenállása már csak egyenlő/rosszabb (tegyük hozzá, nagyobb sebességeken, ahol a gyengébb hajtóművek ellenére is, az F-4-es a gyorsabb gép, de legalábbis a sárkányban nagyobb sebességtartalék van, mint az F-15-ösében).
Harry Hillaker, az F-16-os egyik tervezője nyilatkozta még 1991-ben:
"...There have been debates through the years about just how much technology should be incorporated in any design. The real issue isn't technology versus no technology. It is how to apply technology. For example, the F-15 represents a brute-force approach to technology. If you want higher speeds, add bigger engines. If you want longer range, make the airplane bigger to increase the fuel capacity. The result is a big airplane. The F-15 was viewed as highly sophisticated because it is so big and expensive. In my mind, the F-15 wasn't as technically advanced as the F-4.
The F-16 is much more of an application of high technology than the F-15. We used the technology available to drive the given end, that is, or was, to keep things as simple and small as we could. Our design was a finesse approach. If we wanted to fly faster, we made the drag lower by reducing size and adjusting the configuration itself. If we wanted greater range, we made the plane more efficient, more compact...
...In general terms, it translates into lower weight, less drag, and therefore higher performance. Also, a fundamental indicator of an airplane's cost is its weight. We were well aware that the avionics folks would be putting a bunch of gadgets in the airplane, which would increase weight and decrease performance. We stacked the deck. We made the airplane so dense that there wasn't room for all that stuff.
As it turned out, our high-density design was one of the things that looked as though it might hinder the advancement of the airplane. It was later graded on the amount of unusable space. We had 4.8 cubic feet. The F-15 had almost ten times that...
...Another reason, besides weight, favors small size. Smaller aircraft have less drag. People always talk in terms of drag coefficients. But drag coefficients really don't tell you that much. For example, the drag coefficient of an F-16 is about the same as that of an F-4. However, the F-16 has about one-third the drag of an F-4 in level flight. At angle of attack, it is about one-fifteenth. The airplane's exceptional maneuverability is a consequence of that lower drag and a higher thrust-to-weight ratio...
We had to take this approach because we had to use a given engine, the F100, which had been developed for the F-15. John Boyd had played a part in defining that engine, and he felt comfortable with it. So the engine was fixed. That meant that the thrust was fixed. If we wanted a high thrust-to-weight ratio, we had no choice but to reduce weight.
The range equation can be treated like the thrust-to-weight ratio. The typical approach to increase range is to simply increase fuel capacity. But increasing fuel capacity increases volume, which means more weight and more drag. People think that big is better. It's not. With the lightweight fighter, we wanted to achieve our ends through different means. We increased range by reducing size..."
Ezek az igazán progresszív tervezői megközelítések, amikor nem egy nettó brutális hajtómű teljesítményre fűznek fel mindent, hanem mélységében tervezik meg a gépet, alaposan kihasználva a lehetőségeket.
Ilyen gép például a francia Rafale is.
Aki olvasta a gép tervezőjével az interjút, az emlékezhet, hogy a megközelítés nagyon hasonlatos volt az F-16-oséra.
