Whereas the engines in propeller-powered aircraft generally achieve their maximum efficiency at much lower speeds and altitudes, jet engines and aircraft achieve maximum efficiency (see specific impulse) at speeds close to or even well above the speed of sound. Jet aircraft generally cruise at faster than about M 0.8 (609mph, 981km/h or 273m/s) at altitudes around 10,000–15,000 metres (33,000–49,000ft) or more.
Frank Whittle, an English inventor and RAF officer, developed the concept of the jet engine in 1928,Hans von Ohain in Germany, a decade later developed the concept independently at the end of the 1930s. He wrote in February 1936 to Ernst Heinkel, telling him of the design and its possibilities. However, it can be argued that the English engineer A. A. Griffith, who published a paper in July 1926 on compressors and turbines, also deserves credit.
Great Zimbabwe is a ruined city in the south-eastern hills of Zimbabwe near Lake Mutirikwe and the town of Masvingo. It was the capital of the Kingdom of Zimbabwe during the country's Late Iron Age. Construction on the monument by ancestors of the Shona people began in the 11th century and continued until the 15th century, spanning an area of 722 hectares (1,780 acres) which, at its peak, could have housed up to 18,000 people. It is recognised as a World Heritage Site by UNESCO.
Great Zimbabwe served as a royal palace for the Zimbabwean monarch and would have been used as the seat of political power. One of its most prominent features were the walls, some of which were over five metres high and which were constructed without mortar. Eventually the city was abandoned and fell into ruin.
The earliest known written mention of the ruins was in 1531 by Vicente Pegado, captain of the Portuguese garrison of Sofala, who recorded it as Symbaoe. The first European visit may have been made by the Portuguese traveler António Fernandes in 1513-1515, who crossed twice and reported in detail the region of present-day Zimbabwe (including the Shona kingdoms) and also fortified centers in stone without mortar. However, passing en route a few miles north and about 35 miles south of the site, he did not make a reference to the Great Zimbabwe riddle.
PTI...The government voted against extending free school meals. This is disgusting, Alex Cook, the owner of the eatery, posted on Facebook on Thursday ... DISGUSTING! All 4 are now barred from The Mill & Il Mulino for life ... Travel-starved 'passengers' dine on parked Singapore Airlines jet. Zimbabwe launches dollar-denominated stock exchange ... .
This follows a huge public outcry over the use of an air force jet to fly ANC leaders to Zimbabwe...PresidentCyril Ramaphosa had ordered an explanation from the minister on the use of the air force jet to fly the ANC to Zimbabwe. The ANC was travelling to Zimbabwe to meet with Zanu-PF over the crisis in that country.
The ANC is currently mired in controversy after its senior members led by secretary general Ace Magashule travelled in a SANDF jet for inter-party talks with the ruling Zanu-PF in neighbouring Zimbabwe... It has been confirmed that South Africa’s public protector, advocate Busisiwe Mkhwebane, was probing the use of the SANDF jet by the ANC officials.
In response to Magashule’s apology, the DA said it wants Parliament to be part of determining how much the ANC will pay for the senior party members who used an air force jet to travel to Zimbabwe, TimesLIVE reported ... The delegation travelled with Mapisa-Nqakula, who had permission to travel to Zimbabwe for talks with her defence counterpart.