EXPLORATORY INVESTIGATION OF THE USEFULNESS OF SOME DIFFUSOR SYSTEMS IN ALLEVIATING GROUND-EROSION PROBLEMS FROM THE DOWNWASH IMPINGEMENT OF VTOL LIFTING SYSTEMS
Abstract
An experimental study was perfor d o i ves ig e the pr c ical usefuln ss of two means of expanding the downwash from V OL LIFTING SY TEMS. The downwash was simulate by a i pl col et, gen rated by a circular 1-foot nozzle. Equivalent disc loadi gs be een 1 an 10 psfAN NO L DISTANCES TO THE GROUND OF A QUARTER TO 5 OZZLE DIA ETERS WERE CONSIDERED. The jet axi also was incline r lative to the normal o ground plane at angles up to 45 degrees. Considerable reductions i ma i u ground yn mic pressure (more an 50%) were possible at the perpendicularly i pi ging je Especially on of e systems which he spreading w ob ine by m of rotation gave f vourable results, although increments in required power of bou 35% re e timat d. In the est conditions, however, where the jet was incline rel tive to the ground board, only the oth r system (consisting of co-axial rings with jet flaps he railing edges) was able to influenc he grou flo characteristics favourably In this case, the corresponding calculated incr ase in power required to maintain the s me thrust, was about 90% for this syst m. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1961
- Accession Number
- AD0272020