Can the vertical motions in the eyewall of tropical cyclones support   persistent UAV flight?
  Powered flights in the form of manned or unmanned aerial vehicles (UAVs) have been flying into tropical cyclones to obtain vital atmospheric measurements with flight duration typically lasting between 12 and 36 hours. Convective vertical motion properties of tropical cyclones have previously been studied. This work investigates the possibility to achieve persistent flight by harnessing the generally pervasive updrafts in the eyewall of tropical cyclones. A sailplane UAV capable of vertical take-off and landing (VTOL) is proposed and its flight characteristics simulated. Results suggest that the concept of persistent flight within the eyewall is promising and may be extendable to the rainband regions. 
Chung-Kiak Poh, Chung-How Poh
physics.ao-ph