A350 Question

That appears to be a strake to straighten the flow on the aft wing-to-body fairing. Probably turbulent flow from the upper and lower wing surfaces mixing with the bulbous fairing. Just a SWAG.

 

I'm no aerodynamic guy that can see all those smoky little things buzzing around but I do remember that on the 707 and KC-135 upper wing surface air collided with body flow and set up a drag wave. The wing flow was diverted to the underside of the wing. There is a lot of high pressure air under the wing and perhaps it was getting into a fight with the air coming by the wing to body fairing. I have put in a question with my old group and they will know for sure.

 

These photos are with the flaps down. Not certain but it could be that with the flaps up it make a continuation of the trailing edge. I think I am noticing a pocket for the flap to retract to.

 

I think that you are correct. Odd way to do it , though.

 

Airbus wing fairings are in general larger than Boeing's newer designs. Also they use a simpler flap actuating mechanism than Boeing on most aircraft. On the A350 the wing fairing is much smaller than most Airbus aircraft maybe to save weight as the fuselage construction is more conventional. The extra fairings might have been required to smooth airflow better and add area. A patch job to make up for shortcomings in the design What really gets me is the narrow fuselage on the A350. It looks strange when landing. Buy Boeing and live in peace.

 

Flaps up on this pic.... Image Unavailable, Please Login

 

I don't see that as an extension of the trailing edge. It isn't blended with anything and as far as I'm concerned, it's an ugly added on pastie strake. There appears to be something similar on the strut trailing edge. The lack of finesse of that aft wing fairing would be embarrassing if I had anything to do with it.

 

It lines up when the flaps are up.

https://i.dailymail.co.uk/i/pix/2014/11/20/23546CE400000578-2842712-It_s_also_the_first_of_its_kind_to_have_both_fuselage_and_wing_s-39_1416507123093.jpg

http://www.airlinereporter.com/wp-content/uploads/2014/02/12304107644_79eaa8e2a1_o.jpg

 

Okay, I can see it. It still appears as a flow straightener but again, it's ugly. The upper part of it is a fairing pasted on top of another fairing. Totally bad looking.

 

Probably pretty quiet ride too. I think the A380 is still measured at the lowest dB of any place inside so the 350 can't be too far behind.

 

The A340 used to be the quietist aircraft inside the cabin. That was passed on to the A380. Most comfortable is the 787. I am pretty sure the 747/8 is the quietist widebody outside the aircraft. The A380 is louder than the 747/8 from the ground and interior noise does not matter for cargo other than on Lufthansa and Korean who carry pax.

 

By the way, the C series, now A220 is a good looking aircraft. I used to deal with Bombardier Aerospace years ago to try to improve the reliability on their aircraft flying for the company I worked for. Their answer for everything was it's the airlines fault even though all the airlines operating the aircraft had the same problems and they knew it. I hope Airbus can change that attitude.

 

Okay, I got the word from my guru. That A350 thing is a body and a strake to prevent flow separation at side of body and to lower drag at the flap/ body fairing juncture . It was unbelievably designed this way from the start.

 

Since it is blended on the upper side I would characterize it more as a chine than a strake.

Being designed from the start is much more admirable than having to scab something on later because it was missed in the CFD/wind tunnel work.

Have you ever seen the new trailing edge designs with the wedge configuration, i.e. very thick edge? Not overly aesthetic but apparently provides very measurable aero benefits. This idea is currently flying on the 737MAX aircraft.
https://patents.google.com/patent/US6382561B1/en (oops, sorry, that's an Airbus patent, though it does reference a Lockheed patent)

 

I used the wrong word, thanks. Still trying to control flow and drag.

 

I guess that I grew up with strakes and fences more than chines but this thing is a body with a sharp chine that from what I can see would only be effective with the flaps retracted. It also looks like it would possibly form a vortex from that sharpness and lower surface flow from the wing. Anybody?

 

Well the plane flies most of the time with flaps up so it would make sense the aero should focus on what is going on at cruise. Chines are used on the Raptor and Blackbird so they can't be that bad. Probably made to increase lift.

 

The F-18 has strakes forward that feed airflow to the vertical fins and also produce a vortex in the process. Blackbird could possibly be doing the same thing but as you said for lift. I also thought about the additional lump on the upper surface of the A350 wing/body fairing as a means of accelerating flow to diminish the formation a vortex. Too darn early in the morning for wrestling with this stuff!