The X-planes are a series of experimental United States aircraft and rockets, used to test and evaluate new technologies and aerodynamic concepts. They have an X designator within the US system of aircraft designations, which denotes the experimental research mission.

The maximum content of the chemicals for the welded steel line pipe is lower than seamless steel line pipe. Above specifications for API 5L X42 is under the condition of PLS1, in case of API 5L X 42 PSL2, the chemical properties and tensile strength is more strictly than PSL1. Yield strength and Tensile strength

OSC's X-42 was equipped with a conventional tricycle landing gear and a braking parachute in the aft fuselage. The vehicle was designed for versatile trajectories and short turn-around time on the ground (14 days), making it a true "space launch workhorse".

2008年10月12日 · X-42 则是一种一次性液体推进火箭的试验段，可将 900～1,800 千克的载荷送入轨道。 X-42 采用先进的助推技术、新型的液体燃料，将为未来军用和民用轨道载荷运送任务提供一种廉价而又高效的运载工具。

Don't let its affordability fool you: the X-42 is loaded with features and functions that make taking pictures as creative as it is fun. A 5x optical zoom and AF Tracking merely head up the list of exciting advances on this full-featured camera.

X：管线的线的第一个字母；42：即420,表示钢材抗拉强度>420 MPa

X-42 采用先进的助推技术、新型的液体燃料，将为未来军用和民用轨道载荷运送任务提供一种廉价而又高效的运载工具。 由于 X-41 和 X-42 同属于美国军方高度保密项目，所以关于它们的详细情况很少。

X-42 は アメリカ空軍 が開発していた ロケット。 液体燃料 を用いる 使い捨て型ロケット と推測されている。 計画内容や開発状況の詳細は明らかにされておらず、開発はキャンセルされているものと思われている [1]。

Designed to provide the ideal aspect ratio for an aesthetically pleasing view, the Altitude™ X 42 gas fireplace is a traditional fireplace that you can truly make your own. This fireplace is available with a substantial amount options to help make installation and customization a breeze.

The two-digit number following the "X" indicates the Minimum Yield Strength (in 000's psi) of pipe produced to this grade. Some people really confused about the X42 and X52, today here I will show you the comparison between them.