Mkuu kwa bahati mbaya umeshangaya mambo.
1) YAK 141 ilikuwa ndege yenye uwezo wa VSTOL inayomaanisha uwezo wa kuruka na kutua wima (vertical). Ila uwezo huu hauna uhusiano na stealth yaani uwezo wa kuficha ndege kwa macho ya rada. Ni kweli kwamba Lockheed walisaida Yakovlev kuendeleza Yak 141 wakati Urusi ilifilisika. KAtika ushirikiano huo walipata pia data walizotumia baadaye kwa ndege zao. Ila Yakovlev hawakuwa wa kwanza wa kufanya majaribio ya VSOL. Harrier ya Uingereza ilitangulia, na hata Boeing walianzisha ndege ya aina hiyo tayari. Lockheed walishirikiana na Yakovlev kwa sababu walitaka kushindana na Boeing.
2. kuhusu stealth: msingi wa kihisabati uliwekwa na mwanasayansi wa USSR Petr Ufimtsev. Lakini USSR hawakuendelea kutumia makadirio yake kwa tekinolojia. Mhandisi wa Lockheed alitambua umuhimu wa nadharia ya Ufimtsov na hivyo Lockheed walibuni ndege ya jaribio ya kwanza iliyotumia stealth.
SOMA CHINI
3. Kudai stealth si "big deal" iko mbali sana na hali halisi. Haihusu ndege za kubeba mabomu (bomber) tu kwa umbali mkubwa, inatumika pia kwa ndege za kuwinda ndege nyingine (fighter aircraft). Katika mashindano kati ya ndege 2 kila moja inategema pia rada yake. Ikiwa moja ni vigumu kutambuliwa, itakuwa na faida juu ya nyingine.
Modern stealth aircraft first became possible when Denys Overholser, a mathematician working for
Lockheed Aircraft during the 1970s, adopted a mathematical model developed by
Petr Ufimtsev, a Soviet scientist, to develop a computer program called Echo 1. Echo made it possible to predict the radar signature of an aircraft made with flat panels, called facets. In 1975, engineers at Lockheed
Skunk Works found that an aircraft made with faceted surfaces could have a very low radar signature because the surfaces would radiate almost all of the radar energy away from the receiver. Lockheed built a proof of concept demonstrator aircraft, the
Lockheed Have Blue, nicknamed "the Hopeless Diamond", a reference to the famous
Hope Diamond and the design's shape and predicted instability. Because advanced computers were available to control the flight of an aircraft that was designed for stealth but aerodynamically unstable such as the Have Blue, for the first time designers realized that it might be possible to make an aircraft that was virtually invisible to radar