Everything You Ever Wanted to Know About Engine Cowlings

[NYCA News]

NYCAviation:

Everything You Ever Wanted to Know About Engine Cowlings (http://nycaviation.com/2011/04/everything-you-ever-wanted-to-know-about-engine-cowlings/)

Rarely is much attention paid to one of the most important design aspects of modern jet engines: The cowlings.
[Click to Read Full Article (http://nycaviation.com/2011/04/everything-you-ever-wanted-to-know-about-engine-cowlings/)]

[steve1840]

Good read!

[hiss srq]

To add the the 190 and 737 engine and why that have those different shapes... The reasoning behind that is because on most jet engines the accessory drives and whatnot are mounted on the bottom of the engine... Because of the height of the main gear on the 737 and the hight of the nose gear on the 190 this wasnt possible for maintaining min ground clearnce so they had to move the accessory drives to the side of the engines in the nacelles.

[stratoduck]

Here is a great video showing the sucker doors in action. They open at low airspeeds and high power settings:

http://www.youtube.com/watch?v=ILXZP_iDfks&feature=related

The JT3-C engines, as pictured in the "junk" engine are turbojets. The first turbofans on the 707 were the Rolls Royce Conway engines, but the bypass was minimal. When the JT3-D turbofans came out, they were labeled "high bypass" fans, which at the time was true, but is rather laughable now. The "vacuum" effect of the fan pulled air from all directions so strongly, that a new cowling was required. A blunt smooth large cowl was required, which at the time wasn't possible with the known aerodynamics. The solution was the sucker doors which allowed air flowing forward around the engine cowling to bypass the lip.