NASA’s G-III flying test bed aircraft rests on three pneumatic lifting devices or "airbags" in preparation for loads testing in NASA Armstrong's Flight Loads Lab. The airbags helped isolate the airframe from any potential influence of the landing gear on strain-gage data. The loads tests provided the data from which engineers derived wing load equations that were used to convert strain gauge signals into actual wing-loading information that the airplane would incur during the ACTE research flights.
NASA / Ken Ulbrich
<a rel="nofollow" class="external free" href="http://www.nasa.gov/centers/armstrong/multimedia/imagegallery/G-III_Aerodynamics/ED14-0095-128.html">http://www.nasa.gov/centers/armstrong/multimedia/imagegallery/G-III_Aerodynamics/ED14-0095-128.html</a>