Persistent Aerodynamic Contrails From Propellor Tips

Trailspotter

Senior Member.
Thanks for that. I read the interesting thread. The Bombardier Dash 8 is one of the most common planes here that don't transmit ADSB so I don't normally see them on SHCC. I will have to try to add MLAT which I can get from the HTML port 8080 output.
Most cloud was below 8km. today.
http://www.metoffice.gov.uk/public/lidarnet/lcbr-network.html
 
Last edited:
Seems like it's a combination. More than just propellors at least, as there's contrail coming from most of the wing.

I suspect that the temperature is too high for any engine contrail, regardless of any differences of efficiency. The wing contrail indicates that conditions were right for aerodynamic contrails (just saturated, in this case, as the trail did not spread). The pressure drop across the prop would be much higher (I think) than the wing, and so contrails could be produced at a lower altitude than turbofan planes.
I can see a regular helix in the trail, in the last shot, but I might just be seeing what I want to see..
 
Last edited:

Trailspotter

Senior Member.
I can see a regular helix in the trail, in the last shot, but I might just be seeing what I want to see..
This reminded me a series of photos that I took in Lake District on August 10, 2016 at around 6:50 UTC. It features a Q400 contrail at 23,000 ft that went "from the horizon to the horizon". A close-up of the plane appears to show the contrail being triggered by the prop tips:
IMG_6321.JPG IMG_6322.JPG IMG_6325.JPG Screen Shot 2016-08-15 at 13.18.50.png

I also found a close up video of this plane and its contrail and posted it on youtube:

Source: https://youtu.be/JaKBZLEBgK4



In contrast, the same type aircraft passing over at 25,000 ft a few minutes later was contrail-less as long as I could follow it:
IMG_6326.JPG Screen Shot 2016-08-15 at 13.17.33.png
 
Last edited by a moderator:

Trailspotter

Senior Member.
Very clear in photo #2 blown up. :) What is puzzling me is that they look like a 'single start thread' not a six start...
It looks like a triple helix to me (when it first appears behind the tail). It appears that the Q400 propeller blade angle is not fixed but controlled. Perhaps it could also vary between the blades, so only three blade tips were making contrails in this case:
Screen Shot 2016-11-21 at 11.41.43.png
A crop of a video frame (see the youtube link in my previous post).
 
Last edited:

Trailspotter

Senior Member.
Agreed. I am still trying to figure out what a screw thread looks like when is rotating and translating, and then frozen in time.. Should still be a six start thread, I think.
Sorry, but I've revised my previous post before your reply. It would have to be a six start thread, but only if all blades were at the same angle. But, as appears, their angles are controlled and possibly can vary between the blades.
 
Thread starter Related Articles Forum Replies Date
Mick West Persistent Aerodynamic Contrail Forming @28,500 on 787 Images and Videos: Contrails, Skies, and Aviation 0
Mick West Giant Dark Persistent Aerodynamic Contrail Images and Videos: Contrails, Skies, and Aviation 6
Mick West An unusual persistent aerodynamic contrail Skydentify - What is that Thing in the Sky? 11
Ross Marsden Aerodynamic and Exhaust Mediated Persistent Contrails - When do they Form? Contrails and Chemtrails 52
Trailblazer Persistent contrails at 26,000ft Skydentify - What is that Thing in the Sky? 3
Tapir-mâché Curious-- how low can persistent contrails form? Contrails and Chemtrails 25
Mick West Persistent Trails Survey Shows Chemtrail Believers Only Recently Noticed Persistent Trails Contrails and Chemtrails 32
Mick West 1952 - Condensation Trails From Aircraft - With a 1937 Persistent Contrail Photo - Oldest Ever? Contrails and Chemtrails 3
MikeG "Non-Persistent" and "Non-Visible Chemtrails" Contrails and Chemtrails 29
Mick West Persistent Cumuliform Contrails at 25,000 feet over California? Skydentify - What is that Thing in the Sky? 20
S Persistent Spreading Contrail Contrails and Chemtrails 4
Trailspotter Persistent Blue Spiral in the Gulf of Oman General Discussion 8
D [NeedInfo]Persistent Contrails Picture Show Contrails and Chemtrails 2
M Converting Relative Humidity with regards to water, to Relative Humidity with regards to ice Contrails and Chemtrails 3
O More on debunking "no persistent contrails" Contrails and Chemtrails 12
cmnit Debunked: No persistent contrails in Russia Contrails and Chemtrails 67
Mick West Debunked: The Science Claims of Global March Against Chemtrails and Geoengineering Contrails and Chemtrails 4
Trailblazer Busy Sky over Southern UK - July 30 2014 Skydentify - What is that Thing in the Sky? 4
Dylmar Are there more persistent contrails these days? Contrails and Chemtrails 49
Mick West Debunking "Contrails don't Persist" with a Study of 70 Years of Books on Clouds Contrails and Chemtrails 98
Jay Reynolds Debunked: "Hygroscopic Smoke" Produces Persistent Contrails Contrails and Chemtrails 1
mrfintoil Discussion: False memories and "No persistent trails in the past" Contrails and Chemtrails 46
WavedRhyme Persistent contrails and overcast the day after Contrails and Chemtrails 12
George B Debunk Global Warming can reduce the number of Persistent Contrails Contrails and Chemtrails 7
Mick West Pre 1995 Persistent Contrail Archive Images and Videos: Contrails, Skies, and Aviation 516
Mick West Michael J. Murphy Admits Persistent Contrails Exist. Can't tell the difference. Contrails and Chemtrails 26
M Relative humidity difference between persistent and non-persistent contrails Contrails and Chemtrails 41
G Persistent Contrail Since 1919 Contrails and Chemtrails 0
Mick West Aerodynamic Contrails at 27,000 to 31,000 feet near Sacramento Images and Videos: Contrails, Skies, and Aviation 2
Mick West Explained: Chilean Navy "UFO" video - Aerodynamic Contrails, Flight IB6830 Skydentify - What is that Thing in the Sky? 186
Mick West Four Engines, Flying West over Sacramento Skydentify - What is that Thing in the Sky? 6
Mick West Close Up Videos of Contrails Forming And Evolving Images and Videos: Contrails, Skies, and Aviation 19
Mick West Some "Black" Shadowed Aerodynamic Contrails Images and Videos: Contrails, Skies, and Aviation 4
JFDee Aerodynamic cloud created by mountain Images and Videos: Contrails, Skies, and Aviation 3
Trailspotter Helicopter aerodynamic dashed linear contrail Images and Videos: Contrails, Skies, and Aviation 4
Mick West Debunked: Irrefutable Film Footage Of Climate Engineering Aerosol Spraying [Aerodynamic Contrails] Contrails and Chemtrails 4
F Explained: Video of plane leaving "6 chemtrails, then 2" [Mixed Exhaust and Aerodynamic Contrails] Contrails and Chemtrails 6
Trailblazer Sequence of Aerodynamic Contrails, Gap, Exhaust contrails. At 25,000ft over the UK Skydentify - What is that Thing in the Sky? 5
Trailspotter Alternating hybrid contrails Skydentify - What is that Thing in the Sky? 5
TEEJ Aerodynamic Contrail/Shadow Peoria, Arizona, 25 November 2015 Skydentify - What is that Thing in the Sky? 4
M fuel dumping or Aerodynamic contrail Skydentify - What is that Thing in the Sky? 7
Mick West Asymmetric Partially Aerodynamic Turboprop Contrails at 25,000 and 27,000 feet Skydentify - What is that Thing in the Sky? 8
Mick West A Rainbow Aerodynamic Contrail Skydentify - What is that Thing in the Sky? 9
skephu Aerodynamic Contrails that look like Exhaust Contrails Contrails and Chemtrails 45
Trailblazer Excellent video of vortices and aerodynamic contrails Contrails and Chemtrails 10
Mick West Contrails On the Millennium Falcon in Star Wars Contrails and Chemtrails 4
Marine0811 Plane trail at wings, none at engines? [Aerodynamic contrails, no flaps] Contrails and Chemtrails 4
Rico Debunked: Dane Wigington's Undeniable Footage of Jet Aircraft Spraying [Aerodynamic Contrails] Contrails and Chemtrails 42
Mumbles B-52G aerodynamic contrail Contrails and Chemtrails 0
Balance Debunked: Pilot Forgets To Turn Off CHEMTRAILS while landing [Aerodynamic Contrail, Wake Vortex] Contrails and Chemtrails 109
Related Articles


















































Related Articles

Top