This is sort of a duplicate thread - we have one going on the J-3 forum.
Maybe three of us think the Moose stall is when the lower wing stalls - that is, the turn rate "increased" with bottom rudder. But, since about half the folks who are even aware of the term think it is an "over-the-top" spin entry - a relatively benign maneuver - and at least several think it is just a low level stall with too many meese aboard - I thought I'd ask here.
Can we arrive at an agreement on what the Moose Stall really is? And can you tell me how to duplicate one at altitude? I can get either wing to stall separately in a turn, but so far I have not been able to duplicate the violent vertical line. I want to do so in the Super D before I try it in a Super Cub.
Bob,
Do a search.....TONS of posts on this topic here:
http://www.supercub.org/forum/showthread.php?20076-Moose-Stall/page2&highlight=moose+stall
In short, there is NO way to reliably duplicate a true "moose stall" intentionally, either at altitude or low level. The reason, I believe, is that you have to set up a very specific set of circumstances to precipitate one.
Not to say you can't cause a Cub to stall in a turn....that's a no brainer. But, the "moose stall", as performed by a number of very experienced pilots, is a very specific loss of control, which almost always results in fatalities. And, in my opinion, it always involves a wake encounter, and the stall itself is not preceded by any significant aerodynamic buffet, or other stall warning.
A fellow I know who is a VERY experienced low level Cub pilot experienced one of these, which resulted in the loss of the airplane, and serious injuries but no fatalities....the only one of these I know of where anyone survived.
My recollection, is that, as he described the incident, the conditions were winter, cold, very still air. They were hunting wolves (legally) in mountainous terrain. He had a wolf spotted running down a steep walled canyon, and was circling in the top of the canyon, trying to drive the wolf out the bottom, so his gunner could get a shot. They were in a Super Cub. As they circled, the pilot noted a slow rolling tendency of the plane toward the outside of the turn. There was a canyon wall there, and that wasn't where he wanted to go anyway. So, he input more (coordinated) control inputs INTO the turn to counteract that rolling tendency. At some point, the airplane stalled with absolutely no aerodynamic warning, and rolled hard opposite the turn, and went over the top into the start of a spin.
This very experienced Cub pilot said that the ball was centered, he did not have cross controlled inputs, his speed was well above "normal" stall speed, and he is convinced that he had encountered an asymmetric encounter with his own wake vortex.
In this case, as the airplane went over the top, it impacted the steep canyon wall inverted, and skidded down the mountainside on it's top. Fortunately for the participants, the airplane shed a lot of energy at it's intersection with that mountainside and, while they both suffered serious injuries, neither was killed.
The pilot described this event at a safety seminar in Fairbanks many years ago, and I discussed it with him separately as well.
A couple years before I heard his discussion, I was circling a radio collared wolf in a lazy circle, trying to visually identify him. This was in a shallow valley north of Fairbanks. I was in a Cessna 185 on wheel skis. Again, it was totally calm, cold air. As I circled, the airplane began an uncommanded roll toward the outside of the turn. My natural inclination was to apply more "in turn" control inputs. The ball was centered. Yet, the airplane continued to roll outside. I was in relatively open country, so I simply allowed the airplane to roll wings level and exit the turn, flew out a ways, then turned and re-entered the search for the wolf, who I found shortly thereafter.
At the time, I had no clue what had just happened, and it really puzzled me, but after discussing this with the pilot who described his accident above, I realized that I was probably encountering my own wake vortex in that really thick, still air.
Like the pilot of the Super Cub described above, a lot of the folks who I've known who died in these accidents were VERY experienced Cub pilots, and were very experienced in this kind of flying. I find it hard to believe that many of these pilots were so sloppy as to get themselves so out of whack and so cross controlled that this was the cause of their demise. Go to altitude and try to simulate THAT kind of event.....you would have to have your head so far up your butt to accomplish one of those at low level that it just doesn't compute.
The Super Cubs videos where Roger Stradley demonstrates what he calls a "moose stall" is just a cross controlled stall and spin entry. As noted above, if you can't feel that one coming.....you shouldn't be flying these things. You'd have to be numb.
And, my point is, too many really experienced pilots have succumbed to these things for me to believe that they'd fall into that trap.
There is something else going on in these things, and I believe the unpredictable (and invisible) factor is your own ship's wake. And, that is REALLY hard to simulate.
As noted in the referenced thread, I was able to get our Top Cub to go there with a student at altitude once out of literally hundreds of attempts. And, the airplane initiated an uncommanded roll to the outside of the turn and with no aerodynamic warning at all, it broke over the top and entered a spin. It recovered very quickly, but had we been close to the ground......
Stroll through that old thread. You'll find a lot of theories, most of which I don't buy for the reasons noted here. But there's a lot of reading there....make your own decision.
MTV
