(quoted from post at 12:32:23 02/15/19) MiG 21 had estimated combat life of 200 hours, Russian engine had 300 hour TBO - overhaul time. Peacetime use in Egypt- fly MiG 21 to just over 200/250 hours on engine and then arrange replacement with
rebuild from Moscow. have a dozen engines on shelf in country for couple hundred planes with 75% operational. Possible communist takeover of government, kick out Russian 'advisors' and support, Russians stop
resupply and MiG21s don't have replacement engines-and at just over 300 hours turbine bearing siezed, MiG21 becomes a glider- not a good one. Rest of MiG21s grounded. Egyptian aircraft mech that did work on
commercial planes when not on active reserve duty checks out Rolls Royce that had same design family grandfather as russian engine, gets out tape measure and figure he can put in commercial rolls Royce
engine in MiG airframe, get a field serviceble engine with 2000 hours TBO and 90% performance of Russian engine--and that means 150 or so fighters able to fly safely, demonstrate some combat capability so
politicians can threaten other politicians. Chinese make F9(?) copy of MiG21 with about same copy of Russian engine as short life-BUT for past 10 years have had a upgrade with a copy of Rolls Royce engine
with about 1000 hours TBO- these are used southern China coastal region with a few in service near North Korea, Siberian border region-- and supposed to be a export version offered to Pakistan. MiG19 variant
also supposed to have a better engined version being used domesticaly with a offer for export to preferred customers. Old designs from Russian patterns proven to work at usable level and with some upgrades.
Rumanian IAR has upgrade of MiG21 with Rolls Engine or French made licensed variation, French fire control, radio and is offered for sale at price a bit less than F5 from american export version, competitive
price to Fiat G91 light fighter/bomber. China offers somewhat less capable but cheaper version for some customers. China Tank variation of Russian light tank upgrade from 73mm short gun with 85mm or 100mm
gun from old T34- 20% lighter than T34, able to ford water with kit, narrower for some restrictive roads, better fuel economy- not a heavy slugger against other medium tanks- but good enough support and able
to handle a Scorpion or AMX13, Bradley. Motorcycle- a 250cc variation of old East German Eisenschwein used by police and military, good reputation for reliability, ease of maintainance, some sales in Africa
where 2 strokes still allowed on roads, other is 4 stroke Chinese version of Russian Copy of pre war BMW R71(?) with sidecar sort of like Urals that is sold in USA. MiG15Bis 2 seat trainer with 3 different
engine choices - export offer for trainer use at 3/4 price of T37(?) or BAC Tutor/Constable. Military customers may want expendable at low cost-- but if those customers want a long life for used by Generals
utility vehicle, then maker is advise to watch quality control--dis satisfied customer with rifles, bayonets and larger guns may come back to complain, demand 'blood' payment. RN