Question about supersonic flight.

SR-71s flew above the weather. Stresses on an aircraft going through a weather system are the same whether subsonic or supersonic. A tornado would likely rip the wings off an F-15, supersonic or subsonic. Most supersonic flight occurs well above severe weather systems and definitely above any tornados. Low level supersonic flight uses a huge amount of fuel. An F-15 supersonic (~Mach 1.2) at low level would burn about 120,000 lbs/hr of JP8. That amounts to a very short period spent supersonic at low altitudes.

 

Flying at high speed in turbulence will kill an airplane. It doesn't have to be anywhere near Mach 1. The B-52 was designed to fly at very high altitudes where turbulence was almost non-existent . When they were assigned to low level penetration missions the turbulence started to chop them up. Any airplane is subjected to shear , up drafts and sudden down drafts are like a weather based guillotine and it simply chops up whatever blast through it at high speeds. If you fly on an airliner nowadays and it experiences turbulence, the airframe is designed to cope with it up to the rate of changes that it will face at the airspeeds at which it travels. You can see the wings flex and ripple and feel the " bumps". If the airplane was flying above the speed for which it is designed , it could very well come apart because the structure is not given the time to react to the loads applied, and might not be able to. That might not be a pure engineering-ese explanation but it's the best that I can do right now. Perhaps other chatters can add or correct.

 

I guess that we are talking inertia and acceleration.

 

Most combat aircraft have a weather penetration airspeed to minimize damage in case you have to fly through it during combat missions or emergencies. It is generally well below cruise speed. On the F-111s I flew, it was 350 KCAS.

 

Every military airplane I flew had a warning against any flight into known thunderstorm activity and had specific optimum penetration speeds published in the Dash-1 or NATOPS in the event of inadvertent penetration. For example, for the F-16 it was 300KIAS or optimum cruise, whichever was slower; for the T-38 it was 280KIAS; and for the T-28B it is, oddly, a 125-185KIAS range.

 

Rob- They fly into hurricanes, but nobody flies into tornados. Completely different weather systems. Most of the WW-II fighter pilots had only rudimentary instrument flying ability, according to my father, who was a P-47D pilot in the 86th FBG in WW-II. Many of those losses in weather were the result of spatial disorientation. Plus remember, none of those aircraft had weather radars, so limited clues to how bad the weather was. Maybe a P-61 could see weather, or some of the other night fighters, but even those radars had very limited range and capabilities. Modern fighters (and airliners) can see and avoid extreme weather.

 

Weather looks like a very large radar return, very bright where it is the thickest. Dad got shot at, but the 86th FBG was mostly ground attack. I flew 20 combat sorties in Desert Storm in the F-111F and got shot at, too. We dropped mostly PGMs at night.

 

No, the 86 FBG had moved to France when he showed up. He ended up as part of the occupation forces in Germany after the war. Did not come back until Summer 1947.