A flapped wing will stall at a lower AoA than a non-flapped wing, which alone suggests that a single stall warning vane can't be accurate for both conditions.Why is there 2? I havent recieved a clear or good enough answer from my instructor. I know the outboard is 0-10 degrees of flaps and the inboard is 25-40 degrees of flaps.
He's speculating and so am I, although what I said is based on known characteristics of wings. Piper has not said specifically why they have two. All you can know for sure is that they found one inadequate.Thats what I was thinking but instructor kept saying something along the lines of how the engines were mounted on the wings and could inadvertenly activate the stall warning horn. Thanks alot for confirming my orginal thinking
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I'm pretty sure it's the same on the Saratoga. I haven't flown one in a few months, and it's late, but that seems right.He's speculating and so am I, although what I said is based on known characteristics of wings. Piper has not said specifically why they have two. All you can know for sure is that they found one inadequate.
For the engines to have anything to do with it, you'd have to have a mechanism for why the flaps make any difference to the airflow at the locations where the vanes are located. One that's plausible is that the lower pressure over the wing produced by the flaps moves the slipstream more inboard, which is something that does happen on some airplanes.
I've only heard of this setup on the Seneca and Seminole, both twins, and not aware of it on Piper's larger singles. Anyone know?
That's what I'd think too. The slipstream at the prop has about the radius of the prop arc itself, so I'm skeptical it'd have influence very far out on the leading edge.The stall indicators are located quite a ways out on the wing so I do not believe the engines would have anything to do with it.
Retrieved my Saratoga POH from the attic and it does indeed have two lift detectors.I'm pretty sure it's the same on the Saratoga. I haven't flown one in a few months, and it's late, but that seems right.
I believe where he got that idea from is the reason there is a squat switch which disables the lift detectors on the ground. Would be a long taxi if you had the right kind of crosswind going which blew the slipstream out towards the lift detectors "beep....beep..bee...beepThats what I was thinking but instructor kept saying something along the lines of how the engines were mounted on the wings and could inadvertenly activate the stall warning horn. Thanks alot for confirming my orginal thinking
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I was thinking the same thing having flown the Seminole for my CMEL. I'm guessing from the conversation so far its the stall warning switches on the leading edge of the left wing.What the hell is a Seminole "lift detector"
Cheers
George
I don't believe there's a squat switch cut-out. If you can preflight the horn by lifting the vane, then there probably is not a cut-out. In my Seneca, you could preflight both vanes on the ground.I believe where he got that idea from is the reason there is a squat switch which disables the lift detectors on the ground. Would be a long taxi if you had the right kind of crosswind going which blew the slipstream out towards the lift detectors "beep....beep..bee...beep
Thats interesting. On the single version of the dutchess, the sundowner, it only has one flap.I do not know about other piper products but I know Beechcraft put them on the Duchess. The Duchess has one on each wing. I have flown both and I would agree that it has to do with the angle of attack. The stall indicators are located quite a ways out on the wing so I do not believe the engines would have anything to do with it.
Probably making a joke with respect to how laymen seem to think that “theory” means speculation, guessing, as in not proven. Not how scientists use the word “theory” of course. All of our knowledge of the world is embedded in theories, even the ones that are the most well-supported by the evidence and that no sane person would ever question, such as the germ theory of disease. Theories always remain theories, no matter how obviously true they are.One thing I heard from a Boeing engineer that I thought was funny, "It's weird that we can keep 100's of people safe with only using theory on how to make an airplane.
you can't, the right squat mutes them both on the groundI don't believe there's a squat switch cut-out. If you can preflight the horn by lifting the vane, then there probably is not a cut-out. In my Seneca, you could preflight both vanes on the ground.