Military aircraft vs civilian?

Rufus Plough: Military aircraft are designed for performance. Civilian aircraft are designed to only perform up to a limit. Depending on which aircraft, newer commercial aircraft have innovative designs to help keep the noise down, because of noise pollution from airports around residential areas.Military aircraft are designed strictly for mission requirements. There aren't many creature comforts in them.For instance, the loudest jet engine I've ever heard anywhere has been the F-15. Tiny compared to a 747, but immensely louder. When it took off, it was at mil power and it was loud. Imagine hearing it with full afterburners on. I was used to hearing the tiny engines of T-38s and they sound like insects compared to the P&W F100 engines in the F-15s. It was probably a couple of miles away and accelerating like a bat out of hell, and it sounded like it was right above you.The new 787 Dreamliners from Boeing have engine designs that help to keep things quiet. Here's ! a link to a cutout of the GEnx engine that details exactly what improvements there are over previous generations of jet engines.http://www.popsci.com/military-aviation-space/arti......Show more

Emile Okafor: Jet engines have a reputation for being noisy but actually an unsilenced piston engine and prop is noisier when compared like for like in terms of power and thrust. WWII military aircraft were amongst the noisiest prop aircraft ever developed. They kept pushing performance levels up and up during this time until jets were the more practical or only way to achieve greater performance. During the Cold War, the Sovient Tupolev TU-95 was the noisiest prop aircraft ever due to the prop tips breaking the sound barrier (although these were turboprops).Military aircraft are always designed to achieve mission objectives. Noise abatement is low priority on that list of objectives. Fighters typically demand low bypass turbofans for compactness and to achieve a high jet veloc! ity to reach typically supersonic air speeds. It is the result! ant high viscous shear of this jet that causes the whoosing roar of a jet at takeoff and on high speed, low altiude flyby. Afterburners dramatically increase this noise. With civil airliners, noise is a concern and although the choice of high bypass turbofans for this application is primarily mandated by high fuel efficiency in the high subsonic airspeed cruise range of these aircraft, they are inherently quieter. In addition, the budget of airliner manufacturers to develop noise abatement features is considerable whereas it is minimal for military aircraft manufacturers....Show more

Victor Macallister: Because civilian aircraft must obey FAA noise pollution regulations and can only produce a certain amount of Decibels of noise.Military aircraft are exempt from those regulations.IE: reducing noise adds weight and reduces power in engines, doesn't effect civilian aircraft, but military aircraft need all the weight savings and power they can get....Show more