Post by LOU on Apr 3rd, 2011 at 10:11pm
pj747 said: They are called vortex generators. They help move the air on top of the wing so it gets as close to teh airfoil during the air's entire trip over it so that for landing it helps lower the stall speed to allow for slower approaches and shorter landings. One of our family friends's friends whose our aquaintence lives in McCall Idaho (I think) helped develop the VG's for the Beechcraft Baron.
They are called vortex generators indeed, but you said they help move the air...not really correct.
The small tabs are set at an angle from each other and in rows. What they do is GENERATE turbulence in the air flow which slows the air down a bit and helps to keep the flow of air attached to the contour of the wing, re-energizing the boundary layer. In this case on the 707 they are used to delay flow separation. They are placed at parts of the wing that are somewhat critical. Usually, they are installed on the front third of a wing in order to maintain steady airflow over the control surfaces at the trailing edge of the wing such as the aileron as is the case in the 707 wing.
The 727 has them all over the place including the vertical stabilizer. That helps improve the air flow over the rudders.
from AVWeb
"The use of vortex generators is nothing new. First used in England, VGs have been used on transport jets for decades, and on bizjets since Bill Lear invented them. But historically they were used as an aerodynamic "band-aid" to deal with localized mach buffet problems at the high end of the airspeed envelope. MacDonnell Douglas engineers would routinely scoff at the VGs on Boeing jets and brag, "see, we don't need those things because we got our aerodynamics right in the first place."
The idea of using VGs to improve the low-speed performance of general aviation aircraft came from an ex-Boeing engineer named Paul Robertson."
More reading: http://www.avweb.com/news/reviews/182564-1.html
They are called vortex generators indeed, but you said they help move the air...not really correct.
The small tabs are set at an angle from each other and in rows. What they do is GENERATE turbulence in the air flow which slows the air down a bit and helps to keep the flow of air attached to the contour of the wing, re-energizing the boundary layer. In this case on the 707 they are used to delay flow separation. They are placed at parts of the wing that are somewhat critical. Usually, they are installed on the front third of a wing in order to maintain steady airflow over the control surfaces at the trailing edge of the wing such as the aileron as is the case in the 707 wing.
The 727 has them all over the place including the vertical stabilizer. That helps improve the air flow over the rudders.
from AVWeb
"The use of vortex generators is nothing new. First used in England, VGs have been used on transport jets for decades, and on bizjets since Bill Lear invented them. But historically they were used as an aerodynamic "band-aid" to deal with localized mach buffet problems at the high end of the airspeed envelope. MacDonnell Douglas engineers would routinely scoff at the VGs on Boeing jets and brag, "see, we don't need those things because we got our aerodynamics right in the first place."
The idea of using VGs to improve the low-speed performance of general aviation aircraft came from an ex-Boeing engineer named Paul Robertson."
More reading: http://www.avweb.com/news/reviews/182564-1.html