737's engine mounted on wrong wing!

[avbug]

From D. Lednicer:

To quote from Dick Shevell's AIAA paper "Aerodynamic Bugs: Can
CFD Spray Them Away":

"DC-10 wind tunnel tests showed a significant loss in maximum lift coefficient in the flap deflected configurations, with landing slat extension, compared to predictions. This resulted in a stall speed increase of about 5 knots in the approach configuration. The initial wing stall occured behind the nacelles and forward of the inboard ailerons. The problem was traced by flow visualization techniques to the effects of the nacelle wake at high angles of attack and the absence of the slat in the vicinity of the nacelle pylons. The solution was developed in the NASA Ames Research Center 12 ft. pressurized tunnel and turned out to be a pair of strakes mounted forward on each side of the nacelles in planes about 45 degrees above the horizontal. The final strake shape was optimized in flight tests. The strakes are simply large vortex generators. The vortices mix the nacelle boundary layer air with the free stream and reduce the momentum loss in the wake. The vortices then pass just over the upper surface of the wing, continuing this mixing process. The counter-rotating vortices also create a downwash over the wing region unprotected by the slat, further reducing the premature stall. The effect of the strakes is to reduce the required takeoff and landing field lengths by about 6%, a very large effect."

Rumor has it that Douglas has the patent on nacelle strakes, but the patent calls for pairs of strakes (one on each side). Hence, Boeing aircraft only use single nacelle strakes (737-300, -400, -500 and 767-200 and -300). Boeing calls them "nacelle chines".

The installation error can be as simple as swapping nacelle panels, rather than the entire nacelle. A potentially easy mistake to make on a large shop floor.

 

[UALRATT]

My point is, I bet the nacelles are interchangeable. How much difference does a little itty bitty vortex generator make anyway? On the 767 they are on both sides of the nacelle.

Ask the folks at Boeing because they were the one who took the time to observe airfow around the nacelles and airfoils of their design. Just be sure to not miss that on the next preflight unless your CDL indicates otherwise and that all responsible parties are aware of it...

 

[aa73]

So if that's the case, how did that 737 not crash? Unless it was altered by Photoshop.

 

[mynameisjim]

It would only crash if it was within about 5 knots of stall speed, according to that little blurb up above

 

[SpauldingSmails]

Well apparently according to the photos the plane CAN fly just fine with it on the wrong wing. Remind me never to fly with a pilot from JAT Airways though.

 

[glasspilot]

Makes you wonder what else has been mounted "backwards".

 

[Captzaahlie]

It would only crash if it was within about 5 knots of stall speed, according to that little blurb up above

IT WOULD ONLY STALL (NOT NECESSARILY CRASH ) IF IT WERE AT DC10!

""DC-10 wind tunnel tests showed a significant loss in maximum lift coefficient in the flap deflected configurations, with landing slat extension, compared to predictions. This resulted in a stall speed increase of about 5 knots in the approach configuration."


this test was done on a DC-10 not 737, so your 5 knot assumption is just that ...an assumption. You Einstein types are killing me!

 

[sigler]

That exact thing is a preflight item on the bus. 319 or 320 I can't remember which.

Both the 19 and 21 have them on both sides of the nacelle. The 320 usually only has them inboard, however some LIP aircraft have them on both sides also.

 

[jetdok]

the fan cowls have provisions to move the strake to either fan cowl. example left eng outboard fan cowl is same as right eng inboard fan cowl. So the left eng, left fan cowl can be installed on the right hand engine left side, but the strake must be removed and intstalled in same position as removed.

 

[Captain X]

We should so let foreign carriers operate in the US!

It would be a great way to control costs in the industry.