Originally Posted by
185flier
that aircraft did not have an icing problem
something else is causing this particular aircraft to fall out of the sky there have been too many that did not have ice on them that crashed and killed people
why are there v/g's full span on the aft part of the stabilizor?
does that mean there is an upload on the stab?
VGs add boundary layer adhesion by energizing the boundary layer through the introduction of small amounts of turbulence. Caravan is a large aircraft to have only one engine, and as such has to struggle to meet the single engine Vs0 spec of 61 knots. I wasn't there when the plane was designed but I would guess VGs were added to the tail to help achieve 61 knot stall speed with full-forward loading. A larger horizontal stabilizer control surface would not be used when a small-scale tailoring of performance can be acheived by the addition of VGs near the elevator. VGs are particularly useful at high angles of attack such as those approaching stall. VGs improve low speed performance at a minor cost to parasite drag at high speeds. Since Caravan doesn't go very fast it is a good tradeoff. It is incorrect to assume that VGs are used on an aircraft because of poor stability. Finally, aft mounted horizontal stabilizers have negative loading in all flight situations except when the CG is too far aft or in negative G manuevers.