How do helicopters stay floating in the air? <http://moourl.com/yqsof> Essentially, helicopters stay up for the same reason airplanes move forward through the air. A rotating propeller creates changes in air pressure, lowering it in some areas and raising it in others. Combined with a specially curved wing, the effect is known as lift, and its what pulls an airplane forward or allows helicopters to lift off the ground vertically. Without some sort of rotary propeller system, neither aircraft would ever leave the ground.<http://moourl.com/yqsof>
Details at *http://moourl.com/yqsof* <http://moourl.com/yqsof> - --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "superuj english stories" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/superuj?hl=en -~----------~----~----~----~------~----~------~--~---
