kerbaugh

Hi Pete, Wow! Collaboration with Khamsin is truly exciting news. I'm sure the news will spread like wildfire. I realize that it is the height of presumption to suggest something for the project at this late date but I've only come up with this theory recently. Virtually every plane for X-Plane behaves unrealistically as it stalls. When the stall begins the entire wing stalls at once and the plane tries to roll into a spin. In most flying, pilots avoid getting anywhere near a stall but bush pilots must get really close to stalling in short field operations. Thus the wings of real bush planes must be spin resistant to some degree. For example, one common way of doing that is washout. That's where the angle of attack of the wing decreases from root to tip. Unfortunately, that must be difficult to model in X-Plane because most developers simply give their planes unrealistic roll control in a stall and leave it to the pilot to fight to keep the wings level. I've only found planes from one developer that behave well in a stall and those are Carenado planes. It's my guess that Dan came upon his workaround by accident. Cessna wings look like they have two sections and so it was natural for Dan to model them with two sections. That makes it possible for the two sections to stall at different angles of attack and so I think that Dan arranged for the inboard section of the wing to stall before the outboard section. When you stall most Carenado planes (all of the ones I've tested) they simply lose lift with no tendency to roll or spin. Thus, his wings produce the same general behavior as wings with washout. I know that the shape of the Beaver's wings hardly require two sections per wing but I'm suggesting that you model them that way anyway. Then you should decrease the angle of attack of the outboard section or change it's airfoil; whatever it takes to make that section stall at a higher angle of attack than the inboard section. Then only you and Dan would have bush planes with realistic stall characteristics. (I count Dan's C-185F as a bush plane) -- Gary

I'm having a similar problem with the throttle. On my Mac 10.8.2, Jetstream 1.03 assigns the topmost joystick axis to "throttle" in both the 64 and 32 bit versions. It cannot be reassigned no matter to what I try to reassign it and the Jetstream ignores the axis I already had assigned to "throttle." When I change to another plane, that topmost axis is still assigned to "throttle" but it can then be reassigned.

Hi Javier, I'm hardly an expert on stick pushers but I did some research on them and have some thoughts regarding possible issues. If I'm wrong about any assumptions I apologize; I'm not trying to denigrate. You warned us about it in the manual and have given us the ability to turn it off so I’ve got no problem with it and applaud your effort to model a stick pusher. That said, you did provide me one of the funniest flights I’ve ever seen. I tried to stall the plane onto the runway and it proceeded to “dribble” me down the runway. It bounced me halfway down the runway, slamming me hard enough on each bounce to obliterate any real aircraft. It would make a hilarious movie. I have no experience with stick pushers but Sopwith must be correct; no real system would send the plane into negative Gs to get the nose down and no real control column could move in the blink of a computer eye. Second, it is my impression that you have no delay between the stall warning and the stick pusher. Everything I’ve read indicates that the warnings come first and the stick pusher doesn’t activate until the aircraft is well into the stall regime. There should be a difference between the angle of attack at which the stall warning is sounded and angle at which the stick pusher “feels” the need to take over. I’m not certain about my last observation and I’m not sure that the correct behavior can be modeled in a software flight simulator. After a real stick pusher has pushed the stick forward, it is in a new position and plane’s control surfaces are in a new configuration. Naturally your software stick pusher cannot move my hardware joystick and it seems to me that after your stick pusher is done, the elevators return to where they were before the action, which of course results in secondary stalls. (often many of them) In fact the result resembled phugoid oscillations on steroids. You could model the action of the stick shaker by changing the trim, which would prevent the control surfaces from even wanting to return to their original position. On the other hand, forcing the pilot to retrim the plane might be annoying. (and not nearly as entertaining as being bounced down the runway) Also, if it occurred multiple times the trim would eventually reach full nose-down and the plane would likely become unflyable. I apologize but I don’t see a good way to resolve my last point. It would seem to be the same problem you would have when disengaging the autopilot so maybe you’ve already addressed a similar issue. No matter what you decide, Sopwith has a good point. It’s bound to be more palatable if you do it smoothly. Anyway, this is a great plane and I only want help make it better. I confess that I want to know all I can about big planes and their systems but I prefer flying smaller stuff. This plane is the best of both worlds and destined to become a favorite. I’ll bet that more people can say that about your planes than those of any developer in X-Plane. Thank you so much for everything you've done. -- Gary