Archived posting to the Leica Users Group, 2007/10/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Walt, The shock waves that formed on early wing designs between Mach 0.8 and 1.2 could cause reversal, depending on the aircraft configuration. Starting around the end of WWII, transonic wind tunnels were designed and developed over time to research this critical speed regime and find solutions to these problems. NASA used a slotted test section concept, while we used a perforated test section, in each case provided with a surrounding plenum chamber in which the pressure could be controlled to permit the walls to partially absorb the bow shock and permit continuous operation through Mach 1.0. Even then, models had to be very small in order to avoid blockage problems. Now, this type of testing is quite routine, and most designers have developed concepts to minimize these problems. Jim Nichols Tullahoma, TN USA ----- Original Message ----- From: "Walt Johnson" <walt@waltjohnson.com> To: "Leica Users Group" <lug@leica-users.org> Sent: Wednesday, October 10, 2007 7:04 PM Subject: Re: [Leica] IMG: From the Cigar Box, More Views from the Rockies > Jim > > Any truth to about controls reversing at near mach 1? Remember the great > old English movie /Breaking the Sound Barrier/? > > Jim Nichols wrote: >> Walt, >> >> Our engineers and facilities worked closely with the folks at Eglin AFB >> who decided what stores were needed on each type of aircraft. We have >> two wind tunnels that do a lot of store separation work, to find out how >> a store will move when it is released. >> >> You can imagine how upsetting it would be for a pilot to release one of >> those large drop tanks and find that it pivots around the leading edge of >> the wing and comes back at the airplane. The flow patterns around high >> speed aircraft can cause a lot of unusual trajectories when stores are >> dropped. >> >> Jim Nichols >> Tullahoma, TN USA >> ----- Original Message ----- From: "Walt Johnson" <walt@waltjohnson.com> >> To: "Leica Users Group" <lug@leica-users.org> >> Sent: Wednesday, October 10, 2007 5:10 PM >> Subject: Re: [Leica] IMG: From the Cigar Box, More Views from the Rockies >> >> >>> Jim >>> The mountains are nice but the A10 is my favorite. Damn, those things >>> carry more than a squadron of B17s.Also heard they are hard to knock >>> down. >>> >>> Walt >>> >>> Jim Nichols wrote: >>>> When we visited the Rocky Mountain National Park in May 1991, I drove >>>> my wife's Volvo 740 wagon up to 11,000 ft, higher than I have ever >>>> flown a light plane. The pictures at the top were not spectacular >>>> because of the snow and clouds. However, on the way up, the views were >>>> great. A couple are linked below. >>>> >>>> http://gallery.leica-users.org/v/OldNick/Cigar+Box/Rockies+1991.jpg.html >>>> >>>> http://gallery.leica-users.org/v/OldNick/Cigar+Box/Perch+With+a+View+1991.jpg.html >>>> >>>> Comments and critiques welcomed. >>>> >>>> Jim Nichols >>>> Tullahoma, TN USA >>>> >>>> _______________________________________________ >>>> Leica Users Group. >>>> See http://leica-users.org/mailman/listinfo/lug for more information >>>> >>>> >>> >>> _______________________________________________ >>> Leica Users Group. >>> See http://leica-users.org/mailman/listinfo/lug for more information >>> >> >> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >