1) Breaking the sound barrier causes sonic booms and the formation of condensation clouds around aircraft due to changes in air pressure and temperature. 2) As aircraft approach and exceed the speed of sound, shock waves form which can be seen visually as condensation clouds. This is due to the decrease in air pressure and temperature caused by shock waves. 3) Many photographs show different aircraft like F-14s, F/A-18s, and F-4 Phantoms breaking the sound barrier, clearly illustrating the condensation clouds and shock waves that form in the transonic flight regime.

1. changcy0326 Breaking The Sound Barrier

2. 突破 Breaking the Sound Barrier 音障 編輯配樂：老編西歪 changcy0326 按滑鼠換頁 click for slides advance Music : Take My Breathe Away

4. Sound Barrier and Sonic Boom ( 音障 與 音爆 ) Sonic Boom ( 音爆 ) A loud explosive noise caused by the shock wave from an aircraft traveling faster than the speed of sound. 飛機飛行速度超過音速，由衝擊波所造成而發出的爆炸聲音。 Sound Barrier ( 音障 ) The sudden increase in air resistance that occurs when an aircraft approaches the speed of sound. This is called the sonic barrier. 飛機接近音速時，突然發生空氣阻力的增加，稱之為音障。

6. Transonic flight is often accompanied by an effect known as “Prandtl-Glauert condensation clouds”. As the central axis of the plane, from forward wing area, to spread evenly around the cone-shaped cloud. 跨音速飛行常常伴隨一個效應稱為「普朗特 - 格勞厄脫 凝結雲」 (Prandtl-Glauert condensation clouds) 。以飛機為中心軸、從機翼前段開始，向四周均勻擴散的圓錐狀雲團。 This is due to the shock wave rear pressure decrease, leading to low temperature, causing water vapor condensation. Water vapor condensed into tiny drops, appears to the naked eye like a cloud-like state. 這是由於激波面後方氣壓降低，導致溫度降低，引起水氣凝結導致的。水氣凝結變成微小的水珠後，肉眼看來就像是雲霧般的狀態。 Prandtl-Glauert condensation clouds ( 普朗特 - 格勞厄脫 凝結雲 )

7. When F/A-18 breaks the sound barrier, it really does look like it is flying through a wall! 當 F/A-18 突破音障， 它確實像是通過一座飛行牆！

8. A Tornado fighter bomber pulls up, while moving at high speed, causing a stall (a transient high-speed stall). The drop in air pressure around the wings causes the moisture in the air to condense and, in effect, form instant clouds.

10. 左圖飛機低於音速飛行，中圖飛機以音速飛行，右圖飛機以超音速飛行。 每張圖片聲波都發生了變動。這說明飛機突破音障時聲波的變化。 Breaking The Sound barrier

11. An F/A-18 kisses the hairy edge of the sound barrier at the Moffett Field Air Show.

12. F/A-18F Super Hornet blasting through a "sonic boom cloud" as the jet broke the sound barrier.

13. A USAF B1B makes a high speed pass very near the sound barrier at the Pensacola Beach Air Show.

14. F/A-18F Super Hornet Nov. 5, 2006 The F-14 Tomcat has generated a condensation cloud. Whidbey Island NAS in Sep. 1977

15. Black Knights of Marine Fighter Attack Squadron 314 (VMFA-314) performs a supersonic fly-by. January 29, 2004, Pacific Ocean

16. F-14D Tomcat

17. Apr. 26, 2002 F-14B “Tomcat” performs a high-speed pass while conducting integrated training exercises in the Caribbean.

18. Demo Super Hornet at Oceana Airshow in '04

20. Chicago Air and Water Show (Aug. 20, 2005) F/A-18F Super Hornet, high-speed pass over North Avenue Beach.

21. STS-106, Space Shuttle Atlantis, Sep 8, 2000 JFK Space Center, Florida, USA The Space Shuttle...

22. B-2 Spirit Stealth Bomber. Dec 30, 2002 shows that the extraordinary cloud affect is not exactly tied to the breaking of the sound barrier. Photo is credited to Bobbi Garcia

25. High speed photo pass by an F-14D

26. The F-14 Tomcat is a supersonic, twin-engine, variable sweep wing, two-place strike fighter.

27. F4 PHANTOM II BREAKING THE SOUND BARRIER Using a 35mm camera, a telephoto lens and ASA 400 film, Pat Maloney, an engineering planner, photographed an F-4 Phantom II at the moment it broke the sound barrier at the Annual Point Magu Naval Air Station Air Show. "The photograph of the visible shock is rare," stated Maloney. "It required a humid day, split second timing, and no small measure of luck." Maloney frequently practices photography at the many air shows he attends.

28. F-14 Tomcat aircraft breaks the sound barrier during an air power demonstration. 30 Sep 2000

29. The Blue Angels F/A-18A Hornet San Francisco Ca. (Oct. 9, 2005) performs the sneak pass at speeds approaching 700 mph.

30. F/A 18 Hornet flies faster than the sound, creating a sonic boom and a visual mist during an exercise off the coast of San Diego, California.

31. F-18 Blue Angels

32. F-18 Blue Angels

35. 800px-FA-18F Breaking Sound Barrier

36. Vapor forms around the wings of an F-14A Tomcat aircraft as it passes through the sound barrier 31 Jan 1987

39. Mediterranean Sea (Mar. 30, 2005). An F-14B Tomcat breaks the sound barrier during the supersonic fly-by portion of an air power demonstration.

40. F-14 Vapor Cloud-thumb

41. East China Sea (Sept. 11, 2006) An F/A-18F Super Hornet breaks the sound barrier during an air power demonstration.

43. Russian Fighter Su

45. F/A-18 Hornet Fighter Jet, United States Navy, off the coast of Pusan, Taehan-min'guk - Republic of Korea, July 7, 1999. Condensation cloud as F/A-18 flies at or near the sound speed. Photo credit : Ensign John Gay

46. F14-B Tomcat Fighter Jet, United States Navy, Mediterranean Sea, April 22, 2003

49. 謝謝觀賞 The End Pictures from www & Airliners.Net http://www.slideshare.net/changcy0326