The point?

[Mtns2Skies]

I've often wondered why large aircraft's noses do not come to a finely honed point, wouldn't it improve the aerodynamics of the aircraft?

 

[Everskyward]

I've often wondered why large aircraft's noses do not come to a finely honed point, wouldn't it improve the aerodynamics of the aircraft?

I don't have a clue about the aerodynamics but that's where they usually put the radar and I don't think it would work too well if the nose was a point.

 

[Cap'n Jack]

I'm no aerodymacist...but having established my lack of credentials, I'll take a stab...

The plane has a certain width to carry passengers and/or stuff. Making the front of the plane a "finely honed point" increases the length of the airplane increasing the drag from the skin of the airplane- the parasitic drag. In addition, finely honed pointy noses tend to have visibility issues- that's one reason the Concorde had the droopy nose when landing (although it had an higher angle of attack during landing than most planes too).

 

[Cap'n Jack]

I don't have a clue about the aerodynamics but that's where they usually put the radar and I don't think it would work too well if the nose was a point.

I thought about that too but reflected that the F-15 and F-14 have fairly large radars hidden in their pointy noses that work well.

 

[Dan Thomas]

I've often wondered why large aircraft's noses do not come to a finely honed point, wouldn't it improve the aerodynamics of the aircraft?

Nope. The air ahead of a subsonic aircraft begins to move out of its way well before the airplane gets there; the effect travels ahead of the airplane at up to the speed of sound. Sharpening the nose would achieve very little.

On the other hand, a flat nose would contribute a whole lot of drag. There's a happy medium in there somewhere, between flat and pointy.

See http://video.google.ca/videosearch?...b=0&aq=f#q=+wind+tunnel+&hl=en&emb=0&start=10

An example of this is the Cessna 172; the wings from the M model and on had a blunter leading edge to improve low-speed handling. The stagnation point can move down farther and the airflow over the top still stay attached with a larger radius on the leading edge, so the stall is delayed some and is tamed considerably. There was no cruise speed loss between the pre-M and M-and-on models, even with the blunter edge.

On supersonic aircraft a bunch of strange stuff happens, and sharp noses and leading edges are necessary. The air ain't going to start getting out of the way before the airplane gets to it and the airplane needs those sharp things to wedge it apart.

Dan

 

[Troska]

I was reading an older issue of Flying this weekend, and in an article about the new Cessna Citation whatever, the schnoz was talked about. In the article, they spoke about having significant icing issues if the nose was not round enough and it got too pointy. Here it is, page 40 of April '09's Flying:

"The shape of the nose and radome is critical on a business jet with aft-mounted engines because ice that forms on the nose can break off and fly back into the engines. Pointy objects are good ice collectors, meaning ice will accumulate faster on a sharp cone than a more blunted surface. The issue is so potentially important that the graceful pointy beaks of the Learjet 20 and 30 series even have an anti-ice fluid flow to the radome to prevent ice accumulation".

Tim

 

[flyingcheesehead]

Nope. The air ahead of a subsonic aircraft begins to move out of its way well before the airplane gets there; the effect travels ahead of the airplane at up to the speed of sound. Sharpening the nose would achieve very little.

On the other hand, a flat nose would contribute a whole lot of drag. There's a happy medium in there somewhere, between flat and pointy.

Sounds right to me. I remember hearing long ago and far away that pointy was best for supersonic, and round was best for subsonic.

 

[BillTIZ]

I've often wondered why large aircraft's noses do not come to a finely honed point, wouldn't it improve the aerodynamics of the aircraft?

I always thought the front end of my B-1 was pretty pointy.

 

[BillTIZ]

I was reading an older issue of Flying this weekend, and in an article about the new Cessna Citation whatever, the schnoz was talked about. In the article, they spoke about having significant icing issues if the nose was not round enough and it got too pointy. Here it is, page 40 of April '09's Flying:

"The shape of the nose and radome is critical on a business jet with aft-mounted engines because ice that forms on the nose can break off and fly back into the engines. Pointy objects are good ice collectors, meaning ice will accumulate faster on a sharp cone than a more blunted surface. The issue is so potentially important that the graceful pointy beaks of the Learjet 20 and 30 series even have an anti-ice fluid flow to the radome to prevent ice accumulation".

Tim

Ice accumulation could also block the view of the weather radar.