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Old 26th June 2015, 19:14   #16
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

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On a lighter note seeing the F-86 Twin Mustang , it looks like an identity crisis fighter
We need a car like this for occasions when wifey has had a quarrel with an innocent BHPian

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Interesting airplanes coming up

Mr. Narayan can you possibly do a separate thread on the Custer CCW-5 and the actual principles behind its unique S/VTOL and hovering capabilities?
Steeroid, this is a most unusual and unique aircraft you have picked -one which we only read about - most people even in aviation have rarely heard of it! Over the weekend I will write about it and its inventor Willard Custer after dusting out old copies of Flight magazine. In a single sentence - he invented this unusual method of reducing air pressure over the wing thus augmenting lift. Before helicopters came in it was viewed as a real STOL solution. PS: I am curious how you picked the Custer - are you doing a dissertation on it. The Custer CCW and the MiG-25 Foxbat are cheerfully at the absolute opposite ends of the aviation spectrum.
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Old 26th June 2015, 19:49   #17
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

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PS: I am curious how you picked the Custer - are you doing a dissertation on it.
Not at all - just a general interest in aviation, and my son's specific interest in military aircraft.

From what I have read up about it, it seems to have been a revolutionary design that didn't make it due to its inventor's lack of abilities as a businessman and/or politician. If that design and aircraft had made it big, aviation may have become truly mainstream as it seems to do away with the need for costly infrastructure.

Or so I like to think, but I know very little about this space other than what I read up at a superficial level.
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Old 26th June 2015, 22:34   #18
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

Nice writing! I love the Mig 25/31 more than any russian jets. Its akin to liking the Mercedes w124 in terms of cars. Rugged, built to last, and less electronics and more of brutal horse power. I read somewhere that the design of F-15, the premier American interceptor of the 80's and 90's got its inspiration and cues from the Russian's Foxbat.
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Old 26th June 2015, 22:58   #19
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

Superb article. And you have pictured its capabilities in the best way I have read till date. Usually I skim through many articles but I read this one word by word. All these days we only see about MIGs crashing and that leads people to develop a negative image of it. In this years Aero India, I heard one guy joking "If the MIG takes off, we better keep a watch on it, so that it wont crash into us". But this article has shown us what Russian engineering is capable of.
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Old 26th June 2015, 23:13   #20
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

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The third was the F-86 Twin Mustang developed by North American Aviation from its legendary P-51 Mustang of WW2. The F-86 was used as a long range escort fighter in the years immediately after WW2 by the Americans.
Sirji, it's F-82 - the F-86 is the renowned Sabre !

This is the original , probably first twin boom fighter - the P-38 Lightning.

Indian Aviation: MiG-25 Foxbat in the Indian Air Force-p38_bystronski.jpg
Pic Source


Some more trivia about the MiG-25

The pilots were apparently told not to switch on the radars whilst on ground or at low altitude, in vicinity of the airbase or populated areas. Why? The powerful Smerch radar emitted somewhere around 5000W of radar beam energy, and this was sufficient to microwave living organisms. The suspicions arose from finding dead rabbits and such in the proximity of airbases where Foxbats operated.

The electronics used pure alcohol for cooling. This was a bit of a logistics problem , they had to top up often, not because of evaporative losses or leaks, but because ground crew often drank some of the alcohol to stay warm.

The only acknowledged (by the US) air-to-air kill on the US side in the 1991 Gulf war, was by a MiG-25. On April 25, 1991, an Iraqi AF MiG-25 evaded , closed in and shot down a USN F/A-18C , with an R-40/AA-6 missile. Not bad for a plane that first entered service in 1967. As many as 8 F-15Cs gave chase to the Foxbat, firing upto a dozer AIM-7 Sparrow missiles, all of which failed to hit their target.


The MiG-25 is limited to 2.5G above 60000' - not sure of the exact altitude limitation. At Mach 2.5, its turn radius is about 25km. This is not a failing of the MiG-25, pretty much all aircraft suffer thrust loss, control authority due to low air density , and thus ability to turn.

The R-15 turbojets are notorious for reliability/short life, especially with the "do mach 3.2 once and discard the engines" but these were designed to power cruise missiles, hence long service life was not high up on the designer's parameters, and the powering of a fighter jet was unforeseen.

Unfortunately, I haven't had the (dis?)pleasure of hearing the MiG-25 in person , being a pure turbojet , I suppose this would be a very, very loud airplane to be around.

Last edited by GTO : 27th June 2015 at 12:56. Reason: Uploading pic as attachment
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Old 27th June 2015, 02:20   #21
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

This is one of the articles i thoroughly enjoyed ! It was a delight to my senses. Got to know a lot of information about MIG's. Thanks a Ton or rather Thanks a Mach !
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Old 27th June 2015, 04:15   #22
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

Amazing article and one interesting one! In your analysis of fighter jets where do you rate the current set of sekhoi 30s india has? Also how does the tejas look as a replacement? Asking as our neighbors get world class toys and we shouldnt be stuck with a unworthy competitor.

Also whats the difference between the 25 and the 27?

Currently watching a mig 25 documentary. Have a look


Maddy

Last edited by maddy42 : 27th June 2015 at 04:16. Reason: Added a link
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Old 27th June 2015, 07:49   #23
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Default Indian Aviation: Mig-25 Foxbat in the Indian Air Force

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Amazing article and one interesting one! In your analysis of fighter jets where do you rate the current set of sekhoi 30s india has? Also how does the tejas look as a replacement? Asking as our neighbors get world class toys and we shouldnt be stuck with a unworthy competitor.
The Sukhoi-30MKI is widely regarded as currently the best multi role aircraft in front line service there is in the world. The modifications made by the IAF are what others who have purchased the aircraft have tried to copy. (Eg. MKK).

It is an air dominance fighter which can take the fight to the enemy. The radar has phenomenal range, carries a truckload of weapons, has extreme range, manoeuvrability etc. having said that, it can stand up to most threats that might be experienced on the western front and northern front.

The Tejas is comparable to the Gripen and in some cases outclasses that aircraft as well. There are some kinks which are being addressed, but it is probably the best non western fighter aircraft in its class. Tejas does not replace the Su. It replaces the Light category of aircraft (21, 2K, 23,27). From a capability perspective it is a multi role aircraft ( 21, 23, 27) all are limited multi role aircraft. So yes we will have capability addition.

There are also force multipliers ( AEW,AWACS, mid air refuellers, etc). Which do make us a fearsome foe.

Quote:
Also whats the difference between the 25 and the 27?
The 25 is a rocket with aircraft wings and pilot. It was designed to be a high speed high altitude fighter and reconnaissance aircraft.
The 27 is a swing wing aircraft, which was originally designed as a fighter but proved to be an excellent ground attack aircraft.
Both aircraft have different design philosophy.
As such the 25 is a formula 1 car. The 27 is a Tata 407. ( versatile, rugged, gets the work done).
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Currently watching a mig 25 documentary. Have a look


Maddy
Nice!

Last edited by torquecurve : 27th June 2015 at 07:51.
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Old 27th June 2015, 08:47   #24
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

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Originally Posted by Ricci View Post
Sirji, it's F-82 - the F-86 is the renowned Sabre !

The electronics used pure alcohol for cooling. This was a bit of a logistics problem , they had to top up often, not because of evaporative losses or leaks, but because ground crew often drank some of the alcohol to stay warm. Yes, the Russkies are big vodka guzzlers, and pure alcohol didn't seem to faze them !

The only acknowledged (by the US) air-to-air kill on the US side in the 1991 Gulf war, was by a MiG-25. On April 25, 1991, an Iraqi AF MiG-25 evaded , closed in and shot down a USN F/A-18C , with an R-40/AA-6 missile. Not bad for a plane that first entered service in 1967. As many as 8 F-15Cs gave chase to the Foxbat, firing upto a dozer AIM-7 Sparrow missiles, all of which failed to hit their target.

The R-15 turbojets are notorious for reliability/short life, especially with the "do mach 3.2 once and discard the engines" but these were designed to power cruise missiles, hence long service life was not high up on the designer's parameters, and the powering of a fighter jet was unforeseen.
Ricci Sir Ouch. Ouch! Yes F-82 not F-86. Typo. Mauf kar do. Great thing about Team BHP (and I mean this in a nice way) is that you cannot write any nonsense as there will always be sharp eyes out!

The pure alcohol proves it was a Ruskii jet

You are right about the engines' MTBO as they were in the late 1960s to early 1970s. By the time the late 1970s came about the engine had evolved to the R-15-300BD version which had a MTBO of 1000 hours. Those were the ones we had.
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Old 27th June 2015, 10:24   #25
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

You always remind me of the computer game F22 Raptor.I always loved these machines. I had read a book written by a Russian pilot who actually stole a MIG 25 to turkey. He had described each level of planning and execution in that book.I don't remember the name though.

Ram
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Old 27th June 2015, 11:47   #26
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Couldn't resist from posting this... :P amazing machine! But then...It just needed a little help..

This is at Palam base airforce museum, Delhi.
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Indian Aviation: MiG-25 Foxbat in the Indian Air Force-1435385733068.jpg  

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Old 27th June 2015, 13:00   #27
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

I must congratulate you on yet another fantabulous write up sir. Your passion for aviation really shines through in your writing. Not that we are surprised with the amount of detail knowing what you do to earn your humble living
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Old 27th June 2015, 17:08   #28
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

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Originally Posted by iTNerd View Post
I read somewhere that the design of F-15, the premier American interceptor of the 80's and 90's got its inspiration and cues from the Russian's Foxbat.
The McDonnell Douglas F-15 was being conceptualized and its specifications being finalized at the time in 1967 that the Soviets made the MiG-25 public. The capabilities of the MiG-25 did have a bearing on the F-15 specs mainly in terms of the American need for building a pure long range, highly maneuverable, fast climbing uncompromised interceptor. The designers motto was 'not a pound for air to ground'. This was a time when in the Vietnam war the larger less maneuverable American fighters were having a hard time in dogfights with the more nimble, faster climbing Mig-21's and Mig-19's of the North Vietnamese.

In terms of speed the F-15 topped at Mach 2.5 at high altitudes which was slower than the Mig-25 but at lower altitudes in a clean configuration it can clip at Mach 1.2 versus the MiG's Mach 0.98. The F-15 becoming the world's first fighter with a power to weight ratio of 1:1 and a rocket like initial climb rate of over 250 metres/second were both inspired by the MiG-25

Indian Aviation: MiG-25 Foxbat in the Indian Air Force-x8-usaf_f15d_top.jpg
The F-15's planform looks similar to that of the Mig-25 with wedge intakes, twin tailfins, separated twin engines and a big voluminous nose. The Americans did not copy the Mig-25. It is just that two top class design teams working on similar (but not identical) specifications come up with similar design solutions.

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Originally Posted by maddy42 View Post
Amazing article and one interesting one! In your analysis of fighter jets where do you rate the current set of Sukhoi 30s india has? Also how does the tejas look as a replacement? Asking as our neighbors get world class toys and we shouldnt be stuck with a unworthy competitor.

Also whats the difference between the 25 and the 27?

Currently watching a mig 25 documentary. Have a look
Su-30MKI & Tejas - I will write in a couple of days. Both evoke a lot of emotion. I would like to write something really neat and interesting if you are game.

Wonderful factual documentary. Thank you for sharing. Hadn't seen it, I'm not Youtube oriented.

On the Mig-27....

As torquecurve has said the MiG-27 was a variable geometry wing ground attack aircraft dedicated for that role. It represented the pinnacle of Soviet era Russian design on rugged reliable attack combat aircraft. If the USSR had not collapsed we would have seen some great development on the Mig-27. The MiG-25, as the main article describes, is a high altitude long range stand off interceptor and reconnaissance aircraft. The Mig-27 is used to attack targets of the adversary flying lo-lo-lo. The MiG-25 is used to shoot down targets entering your airspace from a distance (hence 'stand-off'). The second variant of the MiG-25 the RB was a high altitude reconnaissance aircraft which the IAF used. The other main variant was an air defense suppression version.

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Mig-27 with wing at minimum sweep to maximize lift and lower the take-off/landing speed.

Indian Aviation: MiG-25 Foxbat in the Indian Air Force-x11-mig27-drawing.png
Mig-27 line drawing showing the wing at full sweep versus minimum sweep. At full sweep the aircraft is best configured for high speed penetration and acceleration.

Swing wings were all the rage in the 1970s design period. They are a little out of fashion now due to advances in wing design that give modern wings the flexibility of marrying speed with reasonably short take off's without the weight penalties of the swing wing.


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All these days we only see about MIGs crashing and that leads people to develop a negative image of it. In this years Aero India, I heard one guy joking "If the MIG takes off, we better keep a watch on it, so that it wont crash into us". But this article has shown us what Russian engineering is capable of.
The MiG crashes we have suffered from over the past 15 to 20 years are in my opinion due to several reasons the main one being of our bureaucrats stalling the purchase of the advanced jet trainer for over 20 years forcing young trainee pilots to move from the sedate Kiran Mk 2 to the Mig-21U conversion trainers. It is like asking a driving pupil who has just learnt to drive on a M800 with only a few hours of road driving under the belt to get into a souped up BMW 3 and throttle down the highway. Unfortunately our bureaucracy are not rewarded for the decisions they take or punished for the ones they duck. In 1962's China war Krishna Menon the acerbic Defence Minister lost his head, General Thapar the Army Chief resigned in shame but the Defence Secretary who was equally responsible for the incorrect decisions went untouched.
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Old 27th June 2015, 17:26   #29
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Default re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

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Swing wings were all the rage in the 1970s design period. They are a little out of fashion now due to advances in wing design that give modern wings the flexibility of marrying speed with reasonably short take off's without the weight penalties of the swing wing.
That sort of changed with the Su27, didn't it? It did away with the heavy swing-wing config by making the fuselage a part of the wing area (or whatever its called technically). Interestingly the Su27 and the MiG29 were products of the same Soviet design remit for interceptor bombers, but we went in for the lighter MiGs but not the Su27s that were meant to complement it - did the Su30MKI come after the 29s or along with them?

Last edited by Steeroid : 27th June 2015 at 17:30.
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Old 27th June 2015, 23:38   #30
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Default Re: Indian Aviation: MiG-25 Foxbat in the Indian Air Force

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Originally Posted by Steeroid View Post
Interesting airplanes coming up

Mr. Narayan can you possibly do a separate thread on the Custer CCW-5 and the actual principles behind its unique S/VTOL and hovering capabilities?
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Originally Posted by V.Narayan View Post
Steeroid, this is a most unusual and unique aircraft you have picked -one which we only read about - most people even in aviation have rarely heard of it! I am curious how you picked the Custer - are you doing a dissertation on it. The Custer CCW and the MiG-25 Foxbat are cheerfully at the absolute opposite ends of the aviation spectrum.
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Not at all - just a general interest in aviation, and my son's specific interest in military aircraft.

From what I have read up about it, it seems to have been a revolutionary design that didn't make it due to its inventor's lack of abilities as a businessman and/or politician. If that design and aircraft had made it big, aviation may have become truly mainstream as it seems to do away with the need for costly infrastructure.
Steeroid Junior, You seem to be a bright young person with a keen interest in aviation. At the start let me caution you I am no expert on Custer Wings and the last time I read about them or thought about them was 1982. Alright here goes - as you know a wing functions because the air over the wing has a lower pressure than the air under it. The conventional aircraft must reach a significant minimum speed before this pressure differential becomes large enough to generate the lift needed to literally lift the weight of the aircraft off the ground.

The key to the lift created by a wing is the speed of the air passing over the wing and not necessarily the velocity of the airplane itself. When aircraft turn into the wind to take off as they almost always do the speed of the air passing over the aerofoil cross section of the wing is the speed of the forward speed of the aircraft plus the speed of the head wind. This principle has been in place since before the Wright brothers.

One Mr. Willard Custer of USA tried to see if he could invent a wing or device which ensured that the speed of air flowing over the wing was faster than the forward motion of the aircraft. To this end he invented what he called the Custer Channel Wing (CCW) which looked like the drawing below.
Name:  X13 Channelwing.png
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By fitting a piston driven propeller inside a hemispherical duct and fitting it in the centre of the wing he found that the propeller blew air over the rear half of the wing where importantly the flaps are and thus the actual speed of air flowing over the wing was due to the thrust of the propeller rather than just the forward speed of the aircraft. In short he created his own 'artificial wind over the wings'. He also demonstrated that this suction caused by the duct made a lower than normal low pressure over the top of the wing and therefore directly created lift. He built a few examples over a 20 year period (1940s to 1960s) and as experiments they worked.

This gave his experimental aircraft the ability to take off with a super short run of only a few metres versus a couple of hundred metres needed for a traditional STOL aircraft like the De Havilland Canada Twin Otter or the Antonov An-2. I do not know if he ever could demonstrate a hovering capability with proper sustained aerodynamic control. In fact Antonov of the USSR also experimented with this principle but did not find it worthwhile to pursue preferring instead to go down the route of the 'Coanda Effect' for his An-74. Boeing used it in the YC-14 and it is partially used in the C-17 Globemaster heavy STOL transport. Wikipedia has a useful page on the Coanda Effect.

As a theoretical principle of aerodynamics the Custer wing was fine. However the practical application was challenging as while this ensured STOL it was not necessarily the most effective and reliable way to give an aircraft STOL capability and it struggled to give the aircraft meaningful forward speed. Further it is mechanically complex and violently unstable in case of failure of one of the two engines. In the meantime helicopters came and matured and are the ultimate VTOL flying machine for now and with time have matured on reliability and range. Helicopters also have the ability to hover and fly backwards which a CCW cannot.

The basic concept of blowing wind artificially over the wing to stimulate lift is still valid and used in other different ways. Most popular is what is called 'Blown Flaps'. Here compressed high speed jet air is bled out of the engine and blown over the surface of the wing and/or the flaps through many tiny apertures. The photo below of a British Buccaneer scale model shows these apertures very clearly.
Name:  x12 Blown Flaps.JPG
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This blowing actually helps reduce take off speed and improve low speed control by making the air 'stick' to the wing better and thus generate better lift. It works more on the 'make the air flow sticky' principle rather than create just an artificial wind. Incidentally the modern word for this is Circulation Control Wing - CCW!

Custer's Channel Wing has not found practical application yet but it isn't a bad concept and may one day find application in drones or microlights. I hope this helps.

- Narayan
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