ATR Wingtip Vortex Phenomenon
Thread Starter
I REALLY SHOULDN'T BE HERE
Joined: Dec 2005
Posts: 2,458
Likes: 551
From: TOD
ATR Wingtip Vortex Phenomenon
Howdy folks,
Last week, on the way across the LTMA a Blue Islands ATR42 passed overhead at FL170. We were in a thin layer a few thousand feet below, ISA+7.
It was interesting to see a thin but clear wintip vortex extending aft from each wingtip for about three wingspan lengths. The AC was straight and level. Is this a usual phenomenon on ATRs? I've only noticed it before on aircraft manoeuvering agressively (high AoA) and flaps/wingtips of aircraft on approach (high AoA) in humid conditions, never at cruising speeds.
Last week, on the way across the LTMA a Blue Islands ATR42 passed overhead at FL170. We were in a thin layer a few thousand feet below, ISA+7.
It was interesting to see a thin but clear wintip vortex extending aft from each wingtip for about three wingspan lengths. The AC was straight and level. Is this a usual phenomenon on ATRs? I've only noticed it before on aircraft manoeuvering agressively (high AoA) and flaps/wingtips of aircraft on approach (high AoA) in humid conditions, never at cruising speeds.
Joined: Jun 2001
Aviation Qualifications: ATPL
Posts: 1,186
Likes: 59
From: OZ
I have been lucky enough to feel and hear the vortices land on me.
I was walking into Narita village from the airport hotels and the path through the rice fields is directly under the flight path. With wind calm, it was not uncommon for the vortices to fall on us as we walked along the pathway.
I was walking into Narita village from the airport hotels and the path through the rice fields is directly under the flight path. With wind calm, it was not uncommon for the vortices to fall on us as we walked along the pathway.
Do a Hover - it avoids G
Joined: Oct 1999
Posts: 2,201
Likes: 0
From: Chichester West Sussex UK
Speedrestrction
Just to confirm the earlier post by 1jz I agree that with any wing that is developing lift there will be atmospheric circumstances where the wing tip votex will become visible.
Granted the circumstances for them to be visible are more common when the wing is close to Cl max and so the wingtip vortex is at its strongest.
Just to confirm the earlier post by 1jz I agree that with any wing that is developing lift there will be atmospheric circumstances where the wing tip votex will become visible.
Granted the circumstances for them to be visible are more common when the wing is close to Cl max and so the wingtip vortex is at its strongest.
Last edited by John Farley; 19th August 2012 at 14:26.
Joined: Jul 2012
Posts: 121
Likes: 0
From: Tarmac
Vortices visibility isn't only cause of very low temperatures or super cooled water vapor. It depends on the air reaching it's dewpoint ( air cooled to a temperature where it's moisture content becomes visible ), the air that passes above the wing moves inward because lowest pressure point are close to wing root [top surface] n similarly the one passing below the wing moves outward as it tries to ride the wing tip n thus both flows spill n form a vortex. So the greater the CL the greater the pressure differential - low presure vortces n low temp- n more chances of visible vortex.
Thread Starter
I REALLY SHOULDN'T BE HERE
Joined: Dec 2005
Posts: 2,458
Likes: 551
From: TOD
Thank you for all your replies. I understand the mechanism for formation but am more interested the phenomenon of visible vortices in sub zero atmospheric conditions and at low AoA.
Last edited by speedrestriction; 21st August 2012 at 13:03.
Thread Starter
I REALLY SHOULDN'T BE HERE
Joined: Dec 2005
Posts: 2,458
Likes: 551
From: TOD
No, certainly not contrails, as I said: very thin vapour trails extending to about three span lenghts aft of the wingtip.
Incidentally I have seen Saab 2000s, Q400s and a Dornier 328 TP all generate contrails.
Incidentally I have seen Saab 2000s, Q400s and a Dornier 328 TP all generate contrails.
