Editing Lockheed U-2 (section)

===Fuel===
The U-2 has used Jet Propellant Thermally Stable ([[JPTS]]) since the aircraft's development in the 1950s. JPTS is a high thermal stability, high altitude [[Jet fuel|fuel]], created specifically for the U-2. JPTS has a lower freeze point, higher viscosity, and higher thermal stability than standard USAF fuels. In 1999, the Air Force spent approximately $11.3 million (equivalent to $20.58 million in 2023 dollars) on fuel for the U-2 aircraft and was looking for a lower-cost alternative. JPTS is a specialty fuel and as such has limited worldwide availability and costs over three times the unit volume price of USAF's primary jet fuel, [[JP-8]]. Research was carried out to find a cheaper and easier alternative involving additives to generally used jet fuels. A JP-8 based alternative, JP-8+100LT, was being considered in 2001. JP-8+100 has increased thermal stability by {{convert|100|F-change|C-change}} over stock JP-8, and is only 0.5 cents per gallon more expensive; low-temperature additives can be blended to this stock to achieve desired cold performance.<ref name="Simms">{{cite thesis |degree=[[Master of Science|MS]] |last=Simms |first=Christian G. |url=http://apps.dtic.mil/dtic/tr/fulltext/u2/a391242.pdf |archive-url=https://web.archive.org/web/20130927133528/http://www.dtic.mil/dtic/tr/fulltext/u2/a391242.pdf |url-status=live |archive-date=27 September 2013 |title= JP-8+100LT: A low cost replacement of JPTS as the primary fuel for the U-2 aircraft? |publisher=[[Air Force Institute of Technology]] |date=March 2001 }}</ref>

The small landing gear made a perfect balance in the fuel tanks essential for a safe landing. Similarly to [[sailplane]]s, the U-2 has a [[yaw string]] on the canopy to detect [[Slip (aerodynamics)|slip]] or [[Skid (aerodynamics)|skid]] during the approach. A skid during flight with no bank is the hint of an imbalance around the longitudinal axis which could be resolved by moving the fuel to the left or right wing tank.<ref>{{cite interview |last=LaRue |first=Carl |interviewer=Markus Völter |title=Omega Tau Podcast Episode 109 – Flying the U-2 Dragon Lady |url=http://omegataupodcast.net/109-flying-the-u-2-dragon-lady/ |publisher=Omega Tau Podcast |date=12 November 2012 |access-date=20 December 2017 |archive-date=22 December 2017 |archive-url=https://web.archive.org/web/20171222052118/http://omegataupodcast.net/109-flying-the-u-2-dragon-lady/ |url-status=live }}</ref>