I think he means G1,2,3,5. Yep, no 4.
Weird. Wonder why they did that (no 4)?
G1 to G2 had redesigned fuselage. G3 brought redesigned wing and wheels. G5 had 200 lb useful load increase and increase in 50% flap extension from 119 to 150. The latter is a big deal since it helps on approach a lot.
The SR22 has changed a lot over the years.
Most airframes change a lot in their first 15-20 years, because they learn lessons from the first ones out the door.
Mooney went from 150 to 180 to 200 hp, stretched the fuselage, changed from wood wing and tail to metal, did a fixed-gear trainer version, increased gross weights, and made many aerodynamic improvements in their first 20 years.
Cessna's 172 went from straight to swept tail, added a rear window, electric flaps, new engine, and changed numerous other things (they were up to the M model by the time it had been out for 20 years).
Diamond's DA40 has been out for only 12 years, but they've upped the landing weight and the gross weight (separately), re-done the landing gear, significantly changed the interior (panel height/position, electric rudder adjustment, 3 versions of the cargo compartment, ventilation, etc), changed the rudder, certified 3 engines and at least 6 props, etc.
I guess that's why I don't see Cirrus as being particularly innovative. Compared to where other aircraft manufacturers have been at a similar point in their history, they're pretty close. The main things Cirrus has brought about are the chute and the level button.
The question is what sells NEW planes. On the other hand, single door, no step to get up on the wing (Acclaim) etc. in the name of efficiency might be a negative at the $700K price point. Just a thought.
No step? Where do you get this stuff? I even went looking at the for-sale sites to verify, and every Acclaim that has a pic where you'd be able to see the step has a step.
Besides, if it was that big of a deal aerodynamically, they'd simply retract it. Earlier Mooneys had retractable steps, either via a hand crank in the cockpit or a pneumatic auto-retract that ran off the vacuum pump and retracted the step when the engine was started.