Aero question; 'Serrations' on the leading edges.

Ian, what am I looking at?

 

Right front of Mercedes F1 car.

 

Just like you said... they are there to make the air do something it doesn't naturally want to do. Either attach to the side of the car, go into the radiator pod, detach from the car, go under the car... Bottom line they want as low a pressure under the car as possible, it could be to aid in building an air barrier below the side pod to stop the low pressure air under the car bleeding out.

Bottom line they are making the air do unnatural things...LOL

 

Embraer uses a vortalons to control span flow. They my be using a similar technique on the F1 wing. It redirects air moving from the wings root outward.
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Possible also stabilizes turbulent air.

 

The front wing is divided into multiple higher aspect ratio lifting surfaces... more efficient and can be tweaked easier than a single lower aspect ratio surface (span squared/area)

The mess in front of the body, which must act as an inverted upper surface of a wing, is meant to energize the boundary layer and create low pressure attached flow "sucking" the body down. If the boundary layer separates, the inverted lift force is lost, just like an aircraft wing stalling from the trailing edge forward.

 

After looking at that treatment all I could think was that it broke up any smooth stream flow in the area.

 

knew id find the answer somewhere

"The separation of the bargeboard energizes the surface, improving their efficiency, even at a steeper angle of attack. Meanwhile, the floor extending strakes help to control how the front tyres wake affects the performance of the floor, which is especially important in yaw"

Credit Matt Somerfield

 

Huh?

 

simple terms....making the air do more work than it wants to and do unnatural things..

Speaking of front tires, I see a lot of teams are "blowing" the front axle in an effort to form a barrier around the tires so their rotation is not as disruptive.......lots of little areo wizards working deep within the factories of England

 

Some of it looks really strange because not only are they directing air where they want it to go, they are also trading downforce (negative lift) against drag. On combat aircraft, we complicate it even more because we want all three of the above (except positive lift), plus we do not want the airframe to reflect radar energy coherently or put out too much of an IR signature.

Lots of the early Russian jet aircraft had aerodynamic issues that they had to resort to fences to cure. Otherwise they ended up with all kinds of interference drag and funny airflow where you did not want it.

 

Certainement pas!!! With old fashioned turbojet engines it pretty much is what it is and yes when you are in afterburner there is a big hot streak, but with modern turbofan engines there's a huge opportunity to hide the IR signature of the for both fixed wing and helicopter engines.

With a modern fan engine you can mix the fan and core flows down and make the signature really small if the bypass ratio is high. The other thing is that it's the surfaces that provide the signature. That is, if you can cool all the surfaces you can drastically reduce the signature. When you have nice and cool bypass air you can bathe the surfaces that you can "see" with cool air and squelch the signature. If the exhaust is ejected above the wing, then it can't be "seen" from below.

On the F117 the exhaust is ejected in such a way that the signature is drastically reduced, and similarly the B2 has a very low IR signature. On the YF-23 there were two "troughs" behind the engine outlets. These troughs were made from "lamolloy" a double layer structure that was cooled with bypass air so it would reduce the signature of the engines when seen from above.


On the CH47 there is a new technology IR suppressor that uses a double wall surface that that bleeds air into the exhaust and cools it and this really works well...

So actually you can and the designers do control IR signature in applications where you need to even though there is a lot of heat coming out of the exhaust.

 

Like the MiG-15 and 17?

Do winglets do the same thing?

 

Winglets prevent turbulent airflow off the wing tips and essentially look like a wing of infinite span to the airflow. A NASA Langley genius, Richard Whitcomb, who developed the winglet theory, is also credited with the invention of area ruling (wasp waist), conical camber, and the supercritical wing. He won the Collier Trophy for area ruling in 1954.