tcliftonr@cc.curtin.edu.au (06/11/91)
750 MPH ESTIMATE FOR JUMP FROM 120 000 FT. The attempt from 120 000 ft prompted a simulation showing the impact with the atmosphere. Those who are serious about the attempt will want something corrected. An old version of the simulator (since utterly deleted) had a tropospheric model for the density. The tangible aspects of the simulation remain unchanged - times and drag effects. However the peak airspeed is now estimated to be 750 mph when the stratospheric density is included. 0 v AIRSPEED, mph v 160 0 f WIND FORCE, N/kg f 40 ................................................................. f . -exit- . . 120000. f v . . . . f . v . . . f . v . . . f . . v . . f No wind force yet . v . . f . . . v . f . . . v . f v . . . . f v. . . . f10 . v . . . f . v . . f . . v . . .f . . .v . .f . . . v . .fv . . . . .f v . . . . .f . v . . . .f . v . . 115000. .f . . v . . .2f . Initially . v . . . f . velocity increases at . v . . f . the acceleration due to . v . . f . gravity . . . . f v . . . . . f .v . . 110000. . f . v . . . . f . v. . . . f . . v . . . f Drag becomes significant . v . . .30 f . . . v . . f . . . v105000. . f Sometime after 30 seconds, . v. . v f ordinary skydiving techniques become effective . . f v . . . . . f v. . . . . f . v . . 100000. . f . v . . . . f . v . . . . f . v. . . .40 f . . v . . . f . . v . 95000. . f . . v . . . f . Airspeed peaks out v . . . f . when wind drag v . . . f . reaches one gee v . . . f. . v . 90000. . f -here, at 750 mph and v . . . .f 47 seconds v . . . . f . v . . .50 . f . v . 85000. . . f . v . . . . f . v . . . . f . v . . . . f v . . . . f v . . 80000. . . f v . . . . . vf . . . . .v f . . . . v . f . . . .60 v . f . . 75000. . v . f . . . . . f Impact with the atmosphere, v. . . f here appearing as a v . . . f wind force of 1.6 gees v . . . f in this simulation. 70000. . . f . v . . . . f . v . . . . f .v . . . . f v . . . .70 . vf . . . . . v f . . 65000. . v . f Impact lasting 30 seconds or so. . . v . f . . . . v . f Accounting for supersonic drag is . v . f expected to shorten and v . . f sharpen the impact somewhat. v . . . f . . v . . . f . . v . . . f . .v 60000. .80 . f . v . . . . f . v . . . . f . v . . . . f . v . . . . f v . . . . f v . . . . . f v . . . . . f v . . 55000. . . f . . . . . v f . . . .90 v. f Now at subsonic speed and with a . . v . f wind force near normal of one gee, . . v . f the aerodynamics are those of a . . v . f normal skydive. . . . v . f . . . . v . f . . . . v . f . . . .v . f . . 50000. . . f . . v. . . f . . v . .100 . f . . v . Well, that's at 50,000 ft altitude and the rest is straightforward. If you want the rest of the graph, I will mail it to you. Roger Clifton, Kalgoorlie, West Australia.