The designers of the GlaStar/Sportsman wanted an airplane that could be flown in slow flight (not like the new FAA definition, but true slow flight a knot or two above stall) and still have aileron control of the roll axis. They accomplished that for the flaps retracted configuration. The Sportsman (I haven't flown the GlaStar) retains aileron control through the flaps-retracted stall throughout the power range. Power off, with full back stick, it settles into a stable sink with full aileron control. With full flaps, some rudder is required to keep the wings level. I'm still, slowly, evaluating the effects of different aileron rigging.
The Sportsman will spin. One has to intentionally make it spin with flaps retracted. It is easier to enter a spin with full flaps. I have no experience spinning the Sportsman with half flaps.
The crash that started this discussion, the ICON over the lake, would have been easily avoided in the Sportsman (and likely the ICON also) with the turn technique that I described in that thread.
A free-wheeling discussion about methods to make better and safer flying airplanes will be interesting, but may not lead to any useful conclusions. (To me, a better flying airplane would be one capable of pulling to vertical without losing too much speed, like a modern monoplane, but still have snap roll - spin - charactersitics of a Pitts.)
The first step necessary to find a way to eliminate a problem is often overlooked because it is assumed that the problem is clearly understood. The first, and necessary, step is to clearly and succently state the problem.
Please state the spin problem that you would like to fix.
Thanks.
BJC
The problem is the unintentional spin. It is OK and perhaps even desirable to be able to spin the airplane. The problem is that some aircraft have a tendency to enter a spin from what could be a stable stall.
In short, some aircraft are prone to spin and some are not. The goal here is to create a design that is not prone to spinning without detracting from performance and without creating weight, cost and manufacturing or maintenance issues.
To begin with I think we need to have a common understanding of what constitutes a spin resistant airplane.
I will propose the following statements to see what agreement or disagreement follows.
1. The Ercoupe is not a spin resistant design. It is stall resistant and therefore does not have a spin problem. The stall resistant design is a performance limitation that is a limitation for (some or many, pick one) pilots.
2. "The Sportsman retains aileron control through the flaps-retracted stall throughout the power range." This does not make the Sportsman a spin resistant airplane. If the Sportsman is held in a full stall, a wing will drop and without corrective pilot action of aileron and/or rudder the aircraft will spin or spiral dive depending on the CG and amount of elevator control. In short it takes pilot action to prevent a spin at a high angle of attack.
3. It is possible to build a spin resistant aircraft. I can give examples from typical kids kites to ultralights to airliners. I just now built a spin stable paper plane in less than 5 minutes. The Air Bus A330 operated as AF flight 447 made a full stalled descent from several miles high into the South Atlantic ocean without spinning. A TWA B-727 made a deep stall descent from about 20,000 feet with iced pitot tubes. and the Air Bus 320 crashed at the French airshow without spinning. The Cascade Ultralights "Kasper Wing" can make a deep stall descent without spinning. The SGS 2-33 must be forced to spin. What about the Concord crash, Does it look like a spin entry in the final second?
I am sure there are many other examples of spin resistant design as well as spin prone designs. I suspect the Lear jet is a good example of a spin prone design but do not have personal experience to support that statement. I solicit comments on other designs from personal experience. I am particularly interested in comments about the Sonex as it was the Sonex Acro N123SX crash that killed Jeremy Monnett, CEO of Sonex that started the recent interest in this subject. Many aircraft will be average or typical when rated for spin resistance. It would be nice to have some sort of grading scale to cover the range.
4. Before we get into the ideas and merit of design we need to determine the usefulness of the study. There appears to be a large segment of the pilot population that that see no benefit to a spin resistant airplane. Some even see an apparent benefit to a spin prone design. I solicit your opinions.
Note aft CG and generous up elevator above and forward CG and neutral elevator below.
Incidentally, these happen too be flying wings for ease of construction with low cost (scrap) material.
The stalled plane makes a slow stable glide with a 2 or 3 to one glide ratio. The normal configured plane glides with a much faster 5 to one or greater glide angle. We can do better than many existing aircraft designs.