Aircraft nose shapes

[RobWard]

Whilst watching a tv programme about Concorde yesterday, I was struck by a question and hope that you experts can satisfy my curiousity...
Why do commercial aircraft and transports have such blunt noses compared with fighters or Concorde?
I know that they are travelling much more slowly, but from a fuel economy point of view, isn't a blunt nose detrimental?
Thanks to anyone who can provide an answer.

"I love deadlines. I love the whooshing noise they make as they go past." Douglas Adams

 

[tbuelna]

RobWard:

Look into NASA's QSP (Quiet Supersonic Platform)project. It will provide you some insight.

http://www.nasa.gov/vision/earth/improvingflight/ssbd.html

Regards,
Terry

 

[meechu]

Dear Robward,
Corgum is right in saying that blunt noses on a slower aircraft will be having the same advasntage of lesser drag as sharp nose on a supersonic aircraft. The drag matters for the fuel economy as much as any other parameter.
Also sharper noses needs more effort in shaping of the instruments, antennas, and baggages for the occupation of the space offered by the nose portion ahead of the pilots' cockpit. The development cost for these shapely(!) items may fall on the aircraft manufacturer only, which is unnecessary in the case of slower aircraft.
meechu

 

[RobWard]

Thank you for your answers.
It's a good job I'm not an aerodynamicist: when I was a schoolboy all my aircraft were long and pointy.
But, then again, they also had flames coming out of the back and guns firing from the front.
Perhaps I have a hidden genius for supersonic fighter design?
Ok, maybe not...
Seriously though, I had guessed that construction and packaging costs might have had something to do with it, but I'm quite surprised that sharp noses incur a higher drag penalty.
You definitely live and learn.
Thanks again.

"I love deadlines. I love the whooshing noise they make as they go past." Douglas Adams

 

[Sparweb]

I once asked a Twin Otter pilot, what's the difference between the short nose on the -100's and the long nose on the -200's. 2-3 knots was his reply. Dehavilland stretched the nose to make more room for baggage, and I assume that the speed penalty was less of a concern to them. (Doesn't seem to be a compensatory power increase).


STF

 

[prantdle]

Dear robward,

The most important parameter thet sizes the forebody and nose of an conventional transport aircraft is the visiblity of the pilot.

As you see in concord, sharpness of the nose has imposed the complexity of the mechanism that drops the nose to improve the visiblity of pilot during landing operation.

 

[edmacs]

I've had a similar question pertaining aerodynamics of buses. Buses have a quite non-aerodynamic form. But can you imagine a bus with an airfoil like configuration?

Well, I've heard many different (and some quite weird!)aerodynamic strategies for decreasing its drag.
But all concerned with the trailing edge (pressure drag), though!




Eng. Edmar Silva