MIG-25 Foxbat

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@Rej

Racunar 25-ce je vrlo verovatno digitalan, ali se MiG-23 pominje kao prvi ruski lovac sa digitalnim racunarom jer je koristio poluprovodnike dok MiG-25 nije.

Inace u sferi poluprovodnicke elektronike Sovjeti su zaostajali.

@Kaplar

Forumi bas i nisu objektivni a razmisli da je stvarno MiG-25 leteo toliko brzo sto se onda odustalo od tako mocnog motora? R-15 ima oko 200kN potiska na velikoj visini pa ispada da je AL-41F imao cak i veci potisak a danas najbolji ruski motor ne prebacuje 150kN? Nelogicno zar ne?

• 1Ovo se svidja korisniku: ray ban11
  
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Za to oko računara treba uzeti u obzir da je MiG-23 je nekoliko godina "mlađi" od MiG-25.
A za ubrizgavanje vode i metanola čini mi se da je pisalo u onoj Gunstonovoj knjizi što je kod nas objavila zagrebačka Alfa negde oko 1980-te, dakle nakon 1976. kada su imali uvid u Belenkovu 25-icu. Mada ni Gunston nije imun na netačnosti...

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@mean_machine

Da ,na visini 11km pri 100% obrtaja motor R-15B-300 razvija potisak 19800kgs i daje maks brzinu avionu od 2.4M .Naravno sa povecanjem visine opada i potisak i vec na 20km iznosi svega 6000kgs ali daje brzinu avionu od 2.83M ( 100% obrtaja rezim `Puni forsaz` ) .Ovo je zanimljivo ako uzmemo u obzir operativne visine izvidjanja do 27 km i one brzine postignute prilikom izvidjanja Izraela do 3.2M ( na H=20 km je to 3200km/h )

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Sto se poluprovodnicke tehnologije tice i nije toliko bitno ako se ima u vidu sposobnost i brzina sovjetskih analognih racunara -procesora tog doba ( 60/70te) .

@Luka

Ubrizgavati smesu vode i metanola u kompresor mislim da nema smisla ako znamo da motori bilo TMM bilo TVM moraju biti imuni na masovni ulazak vode ( kise ,kapi ) itd ..Jedino rekoh ranije ako ne postoji opcija ubrizgavanja te smese u komoru sagorevanja ili direktno u forsaznu komoru .

• 1Ovo se svidja korisniku: Mercury
  
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Kaplar ::Pa navodno je 25-ca sa AL-41f motorom bez problema išla na 4maha, nešto kao da sam na ruskim forumima pročitao 4,25maha.

Dalje, ne znam da li ste dobro slušali, boja je bila plava na čeličnim delovima konstrukcije što govori da e temperatura prebacila 520stepeni celzijusa. Sami izračunajte koliko je to km/h.

Hm, kako postici toliku brzinu sa TVM ( turbo-ventilatorski motor tj dvostrujni TMM ) ,veoma veoma tesko .Na H=20km je tih 4M oko 4000km/h a 4.25M malo vise, to je zaista previse ???

Inace nedavno procitah ( cini mi se` forums.airbase.ru` ) ispovest jednog pilota 25ce a koji je kasnije leteo i na Lisicaru .Poredi ih i odmah na pocetku razjasnjava da je `25` bio mnogo laksi za upravljanje nego li teskas `31`. Dosta je manje 25ca izgubljeno u udesima i raznim incidentima nego njegovog naslednika .Jednostavno Lisicar je bio pretezak ( tokom 35 godina upotrebe izgubljeno oko 50 aviona ) a `25` se pokazao odlicnim za upravljanje sa stanovista jednog pilota u celom dijapazonu brzina od malih do onih najvecih u stratosferi cak i do onih veoma malih ( oko 100km/h ) kad se dinamicki iskace na 30 i vise km pod odredjenim uglom .

Jedina mana mu je sto se tog apsekta tice bila brzina u prilazu i sletna brzina ( 300km/h ) zbog koristenja TMM i velike sletne mase .No i to je prolazilo bez nekih poteskoca za iskusne letace .

Koliko vidim na wiki ,maks brzinu 3000km/h ili ti M 2.83 postize na H=13km

Citat:Максимальная скорость на высоте, км/ч (м) 1440 (0) 3000 (13 000)
Максимальное число Маха 2,83


Ovaj parametar valjda vazi i na H=20-25 i vise km .Trebalo bi ako se prenosi podatak da su Indusi na svojim `R` leteli iznad Pakistana pri 3.2 M na H=27km

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Ako mogu da uskocim u diskusiju, sta bi znacilo ubrizgavanje vode u motor? Tj sa kojim ciljem?

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^

Imas predhodno postavljen komentar/citat ,ubrizgavanje te smese navodno doprinosi forsiranju motora tj povecanju potiska ,no taj tehnicki detalj jos nismo nasli na nekom crtezu ili skici .

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Da videh to, nego konkretno voda, kako ona doprinosi povecanju potiska?

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^

Ne voda ,vec smesa vode i metanola navodno sto se cini barem meni nemoguce ??? Pogledaj onu sliku i komentar na svapskom ispod .

• 1Ovo se svidja korisniku: ray ban11
  
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Aha, ja pogresno protumacih A ovaj svapski mogu samo da gledam

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MiG-25 Foxbat in the Indian Air Force

Citat:This is the story of the fastest, highest flying aircraft to ever don the tri-colour roundel of the Indian Air Force (IAF). It is dedicated to the men of Nos 102 Squadron 'Trisonics' who flew and maintained these big beautiful birds.

To know your opponent well is the first step in knowing where and how to defend yourself. The Indian Air Force (IAF) has maintained a stream of reconnaissance aircraft since World War II to look deep into enemy territory and record matters of interest. The foremost of these reconnaissance aircraft was the beautiful, powerful and impressive MiG-25RB known to NATO as the 'Foxbat' and christened 'Garuda' in IAF service. This photo essay is on the MiG-25 in the IAF and does not cover all the variants the Soviets built. The aircraft is variously referred to as either Foxbat or MiG-25 in this narration.

Speed: How fast did the Foxbat go - Mach 2.83 was the top speed on reconnaissance missions at high altitude i.e. ~3000 kmph. Momentarily in clean condition and with a partial fuel weight the reconnaissance aircraft could touch Mach 3.0. Its top speed recorded, officially at least once, is Mach 3.2 or ~3400 kmph. Mach 1.0 is the speed of sound - 1225 kmph at sea level, 1062 kmph at 60,000' altitude. Several supersonic fighters can get to Mach 2.0 like the MiG-21 or Sukhoi Su-30 but can sustain that speed only for short durations. The MiG-25 on the other hand could, when needed, sustain Mach 2.5 (~2700 kmph) for an entire reconnaissance mission while over hostile territory. Therein lay the difference - the MiG-25's sustained speed was equal to or above the dash speed of all other fighters of whichever make or country - this was true in 1970 and is still true today.

How fast is fast: At 3000 kmph you are travelling at 833 metres/second which is akin to the speed of a bullet from a high powered rifle or the speed of a shell from a powerful naval gun. Once in 1972 a Russian pilot flying his MiG-25 was on a reconnaissance mission over Israel flying across from Syria to Egypt a distance of roughly 600 kms. He was threatened by missiles fired from Israeli F-4 Phantoms. The Phantoms could not reach any where close to the altitude of the MiG so they fired off their Sparrow radar guided missiles but the Russian simply pushed the throttle to full afterburners and out ran the missiles. The Israeli radars tracked him flying at Mach 3.2 i.e. 3400 kmph some of the way across the Sinai from Syria to Egypt . The overload of flying the aircraft at Mach 3.2 for a several minutes continuously damaged his engines beyond economical repair but set the practical boundries of how far and fast a MiG-25 could go. On a subsequent occasion, a short while later, the Israelis were more prepared and approached another MiG-25, photographing their positions, from head on instead of the near impossible tail chase. The Israeli F-4 Phantoms fired their Sparrow missiles upwards onto the incoming but much higher MiG-25. Aircraft and missile were closing in on each other at a relative speed of over 5500 kmph. The Sparrow missiles radar and guidance computers could not cope with this high a closing speed and failed to lock on to the MiG-25. This was a new phenomena for aircraft and missile designers world over to ponder over.

There is some amount of contradicting data on the web about the Foxbat's speed - some bombastic, some Western sources deliberately playing down the aircraft and some plain incorrect. So after re-reading my 1996 edition of Brassey's World Aircraft Directory the as close to authentic data (that I can lay my hands on) for speed at 42,000' is:-

Never exceed top speed: Mach 3.2 ~ 3400 kmph
Normal top speed: Mach 2.83 ~3000 kmph
Sustained top speed: Mach 2.5 ~ 2650 kmph
Recce mission cruise speed: Mach 2.35 ~ 2500 kmph

……….You read right that is the cruise speed of 2500 kmph i.e. 694 meters per second. And the MiG-25 could sustain that for over 1000 nautical miles (1852 kms) ie fly from Delhi to Bangalore at 2500 kmph on internal fuel alone! Fighter aircraft speed is defined by Mach numbers and not kmph as how many kmph's a Mach number represents reduces with altitude. Hence the kmph figures above may vary a little from source to source depending on what altitude the source assumes. Unfortunately I do not have Yefim Gordon's definitive directory on the MiG-25 published after the cold war.

How high could a MiG-25 go: How high did the Foxbat go…….the short answer is high enough to view the curvature of the earth. The aircraft's typical recce mission cruise altitude was 65,000' to 80,000'(~24 kms). It could go higher as you would like to leave climb and maneuver room above you to engineer an escape if it were ever needed; 88,000' (~26 kms) was the usually accepted combat altitude by Western analysts. As civilians we will never know. These educated guesses should be viewed in light of the fact that in 1973 the MiG-25 set a FAI recognized world record of altitude to which a 1000 kg payload is carried - 115,580' (35,230 metres).

How high is high: Combat altitude is the one upto which an aircraft can maneuver, still climb at a very slow rate, roll, take a turn etc. Aircraft especially nimble ones like a fighter can usually zoom climb in a ballistic trajectory to still higher altitudes and hold on there momentarily. Alexander Fedotov the Chief Test Pilot of the MiG Bureau set an absolute world record of 123,520' (37,650 metres), in 1977, for a jet turbine aircraft taking off and climbing on its own engines. The record remains unbroken. He used a lightened and souped up version of the MiG-25RB that our IAF used.

sa foruma :

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