RUSSIA’S A-10 WARTHOG: The Su-25 “Rook” Attack Jet, and Its Gun

A wingtip camera captures a gout of flame as the Su-25 fires its primary weapon - an 80mm unguided rocket. Although, unlike the A-10's GAU-8, the Rook's 30mm GSh-30-2 cannon is considered an auxiliary weapon, it is no less fearsome.

The A-10 “Warthog” attack aircraft is beloved by pilots and gun enthusiasts alike, and not the least because of its powerful 30mm GAU-8 Gatling cannon. On the other side the Cold War, though, another aircraft was developed with matched an equally rugged and dependable airframe to an equally fearsome cannon: The Sukhoi Su-25 is called the “Frogfoot” by NATO, but to those who fly it and those who depend on it alike, it is the “Grach” (Грач, “Rook”). This red bird of death has overseen battlefields from Afghanistan to Syria, packing rockets, missiles, and its own potent 30mm gun. It is a twin engined jet with a pragmatic appearance, somewhat smaller than the A-10, and designed more as a generalist attack aircraft than a direct counter to enemy armor. The concept behind the Su-25 goes all the way back to before World War II, when the Soviet Union was exploring attack aircraft as part of a program that eventually led to the famous Il-2 Sturmovik. A tactical aircraft that can carry bombs, guns, and rockets in direct support of infantry was a concept that the Russians pioneered, and which had its baptism in fire on the Eastern Front of WWII against the Germans. Today, the Su-25 carries on that legacy in service with the Russian Federation and 22 other countries. But this is a gun blog, so let’s talk about its gun.

The Su-25’s powerful, fast-firing, and lightweight GSh-30-2 cannon. Image credit: Marcel Meres, used with permission.

 

Like the A-10, the Su-25 packs a powerful 30mm fast-firing cannon, but there the similarities between the two guns end. While the A-10 uses the electrically-driven GAU-8 Gatling cannon, the Su-25’s gun is based on the Gast principle, which is little if at all used in the West. The Gast principle uses two barrels and actions side-by-side, with each moving parts group connected to the other via a two-ended lever arm connected to a central pivot point. When one barrel fires, it causes its action to move rearward, which forces the other action forward, feeding a round into the second barrel, which then fires. This means each action acts as an accelerator for the other, enabling extremely high rates of fire. How high? The Su-25’s GSh-30-2 cannon has an approximate rate of fire of 3,000 rounds per minute, comparable to the 3,900 RPM of the GAU-8. The Gast principle comes with substantial advantages: It is far simpler than the Gatling principle, and due to mean gas-driven does not need any “spin up” like a Gatling.

The Gast principle, illustrated.

 

Also, because it uses only two barrels in a single housing, a Gast gun can be made as light as 2 times the weight of as a single-barreled cannon, while Gatlings must be five to seven times as heavy. For comparison, the GSh-30-2 Gast gun is only 2.3 times the mass of the single-barreled GSh-301 (used in the Su-27 and MiG-29 fighters), while the GAU-8 is 6.1 times the mass. In an attack aircraft capable of carrying thousands of kilograms of ordnance, this is only a small advantage, but the efficiency of the GSh-30-2 versus its Western counterpart is still notable. However, the GSh-30-2 does have some disadvantages. When encountering a dud round, the electrically-driven GAU-8 simply cycles on through. With a gas operated gun, this would normally cause a jam that would stop the gun until the aircraft landed. However, the GSh-30-2 includes a system of blank cartridges (1 per barrel) which can restart the gun if it misfires. Compared to the A-10, the Su-25 carries a much lower ammunition load – 250 rounds versus 1,174 rounds for the A-10. This lower ammunition load has to do with differences in the tactics of the two nations. While the US saw the gun and the Maverick missile as the primary weapons of the A-10, the Soviets considered the gun auxiliary to the Su-25’s primary weapons, which were at the time unguided rockets, bombs, and guided missiles like the Kh-25ML.

Su-25 on static display, with a full wingload of empty B-8M1 rocket pods. In practice, this would mean a combat load of 160 80mm rockets, each one producing an explosion equivalent to a 105mm artillery shell.

 

Unlike the GAU-8, the GSh-30-2 is braked, allowing the center of fire to be slightly offset from the centerline of the aircraft. High explosive incendiary (ОФЗ, OFZ), high explosive incendiary tracer (ОФЗТ, OFZT), armor piercing high explosive (БР, BR), and “multi-element” high explosive fragmentation (МЕ, ME) rounds can be carried. This arguably increases the efficiency of Su-25 fire versus the A-10, which has only depleted uranium armor piercing incendiary (API), high explosive incendiary (HEI), and training practice (TP) rounds available. Restrictions on the use of ammunition with depleted uranium projectiles means that, in practice, the GAU-8 typically fires a mix of HEI and inert TP ammunition.

The large siamese muzzle brake of the GSh-30-2. Image source: commons.wikimedia.org

 

Once upon a time, footage of the elusive Russian Su-25 Rook was few and far between, but for us in 2017 that has all changed in recent years, with footage coming out of Russian action in Syria, as well as of Ukrainian Su-25s flying in the War in Donbass.



Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at nathaniel.f@staff.thefirearmblog.com.


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  • BattleshipGrey
    • Brett baker

      I think you’ve just suggested TFBTV’s 1st build project.

      • BattleshipGrey

        That’s a killer idea! We can get a bunch of articles out of it. Pete can take us through how to get a Destructive Device approved, Nathaniel can walk Patrick through the blueprints as he builds and Andrew could do up the ballistics gel (in a pool).

    • Realist

      Great clip, though it looks like that “pew pew” machine could use a compensator…

    • B-Sabre

      Pitch down much?

      • Ron

        done to reduce the beaten zone

    • James Young

      Wow, and only costs as much as one SCAR 17S

    • Edeco

      Surprisingly affordable.

      *resentment of NFA/Hughes amend’t intensifies*

      • Timmah_timmah

        Seriously.

  • Brett baker

    Do Russian troops prefer the 30mm cannon over rockets, like their American counterparts?

    • Tym O’Byrne

      When in Russia, you dont prefer the 30mm cannon.

      The 30mm cannon prefers you.

      lol

    • -V-

      Judging by the number of hard points and the article, 80mm rockets are the ordinance of choice, the gun being a backup weapon. Russian artillery in general tends to be very rocket heavy in comparison to western forces.

    • int19h

      Russia/USSR has a very long history of rockets being a primary air support weapon. You know the famous Katyusha rocket artillery in WW2? That weapon was developed around the already-existing RS-82 and RS-132 rockets, which were originally designed to be used from the air.

      Russians have a fondness for MLRS in general, both air- and ground-based. If you look at footage in Chechnya, Georgia, Syria, Ukraine etc, you’ll see them (mostly BM-21 Grad) being used a *lot*. US seems to emphasize conventional artillery more, judging by Iraq and Afghanistan.

  • Major Tom

    Ask Battlefield 3 veterans of their opinion of the Su-25 Frogfoot. Beware of thrashing from Kharg Island Rush flashbacks where ace pilots could almost single handedly destroy the entire team with one.

    • therealgreenplease

      What do you mean “*almost* single handedly”? That was me, kind sir, camping your carrier. I was also the reason DICE made the spawn AA in BF4 automated. By the time I was finished with my BF3 “career” I’d earned that 100 service star dog tag five times 😉

      • Major Tom

        I did the same. I could deprive an entire team of any vehicle on that map.

        While using a controller to boot! I wasn’t some joystick or mouse/keyboard hacker scum!

      • iksnilol

        The feeling when I only reached level 50 because I got the suppression ribbons/medals so often.

        Feelin’ outta my league here, guys.

  • GPSrulz

    Have you noticed the Russians are no longer using Gast guns and using autocannons guns on the newest fighters? I’m a summing the Gast guns probably aren’t the most accurate: two barrels = two POIs; plus a lot of movement in the action.

    • Giolli Joker

      I don’t think that movement of the action matters much, when the all gun flies at several hundred mph.

      • And it is a gun being aimed by the mk1 eye that is moving at several hundred mph. Airbone guns without some sort of aiming optic attached to them aren’t exactly precision weapons.

    • Major Tom

      Might be more cost and practicality concerns. The GSh-30-1 on the Mig-29 for example is a revolver cannon. Those are way simple to make and maintain relative to Gatling or Gast designs.

      • Tony Williams

        “The GSh-30-1 on the Mig-29 for example is a revolver cannon.”

        Not so – it is a single-chamber short-recoil gun, which weighs less than half as much as the twin-barrel GSh-30 or the nearest western equivalent – the Mauser BK 27 revolver cannon. The performance of the GSh-301 is simply amazing for its size and weight, with a rate of fire of 1,500-1,800 rpm. The MiG-29 and Su-27 families were originally intended to take the GSh-30, but when the GSh-301 came along that was promptly adopted instead as it saved weight while still being very effective.

        • Likvid

          GSh-30-1 pays for it’s performance with really short lifetime though. The entire gun is “working on the edge”. But changing gun every now and than is still cheaper than single goddamn missile.

          Which reminds me GIAT-791 – 2500 rounds per minute through single barell lol. I wonder after how many rounds that barrel is ruined, even with short bursts.

  • Iggy

    I’ve always liked gast guns, there’s something so brutally efficient about the concept, and the fact it was created at the tail-end of WWI lends itself to all kinds of fun diesel-punk what-if’s if the design had been appreciated more at the time.
    I might be confusing it with another Russian plane, but as I understand it the Su-25 mainly uses it’s wing-mounted stuff because firing the gun has a tendency to crack the airframes.
    Also one of the reason the A-10 as wonderful as it is has so many weird little deficiencies (like ammo load outs) is the Air Force has basically taken every opportunity to avoid having to fund modernisation programs for it.

    • Tony Williams

      “I might be confusing it with another Russian plane, but as I understand it the Su-25 mainly uses it’s wing-mounted stuff because firing the gun has a tendency to crack the airframes.”

      That would be the MiG-27 and its six-barrel 30mm GSh-6-30 – link to appear when the moderator permits.

      • Both aircraft have had “shake all the bolts loose” kind of problems with their guns, it was just worse with the MiG-27. Like we learned with the Apache, 30mm ain’t a very forgiving cannon round for aircraft.

        • Likvid

          It’s more because of ridiculous RoF. GSh-6-23 is also really violent (to the point they later reduced RoF), even GSh-23L is still quite punishing (23x152mm is significantly more powerful than 20x102mm, though).

          • Tony Williams

            “GSh-23L is still quite punishing (23x152mm is significantly more powerful than 20x102mm, though).”

            The GSh-23 fires 23 x 115 ammo; the 23 x 152 is for the AA gun.

  • phuzz

    The SU-25 is less ugly than the A-10; Discuss.

    • Mr. Fosi

      I think the A-10 is beautiful. Some people don’t like needle noses, pointy wings, and low-slung engines.

      • Brett baker

        If you’re about to get overrun, either one is hotter than the Playmate of the Year!

      • iksnilol

        So you like short and fat guys/chicks?

        Now we know why those genes survived.

        • noob

          More meat on your bones means better survivability during bad times.

        • If they’re coming to my rescue with a BFG, heck yeah!

    • tazman66gt

      It’s just a Russian copy of the aircraft that lost in the trials against the A-10, the Northrop YA-9.

      • gunsandrockets

        In some ways it might superficially appear so, but not really. The Frogfoot is a very conventional swept wing subsonic jet, with typical performance for that type of airframe. Even its hardening vs ground-fire isn’t that unusual for a jet, as the earlier A-7D was also hardened, though not to the same degree as the Frogfoot.

        The A-X program with its particular performance requirements of long loiter combined with heavy payload STOL ability meant straight winged airframes and low top speed. The A-X really had as its genesis a desire for continued service of a plane like the A-1 Skyraider.

        • XT6Wagon

          Its a copy in layout and function. Not sure quite why they seemed to assume that the USAF always knew best, but way too many bad USAF ideas ended up with russian copies.

          • gunsandrockets

            Sure it’s a copy, sure it is. Aside from the swept wings vs straight wings, low tail vs cruciform tail, flush canopy vs bubble canopy…

      • Tritro29

        It is smaller, lighter, more powerful, lower sitting, has a smaller wing span and area. I mean it must be a copy …

        • Google is useless at the moment, but the similarities are more than just skin deep; it’s not an exact carbon copy of the YA-9, no, but it’s pretty clearly just as much based on it as Buran was on the STS.

          • Tritro29

            Huuum based on what exactly? The engines, layout, size, weight and avionics solutions are like night and day.

        • tazman66gt

          So, its a less capable copy than the YA-9.

          • Tritro29

            It carries twice the ordnance, flies faster, has higher ceiling. Never mind, I forgot to see who I was replying to.

      • Ben Loong

        That’s a ridiculous assertion. The A-X program and the design competition that spawned the Su-25 happened concurrently, with Sukhoi’s design having being finalized in ’68 while Northrop’s YA-9 proposal was submitted in ’70. The prototypes for both aircraft were built and flew in the early to mid-70s.

    • James Young

      The A-10 is a much more unique look. I guess it’s personal preference but the A-10 looks awesome imo

  • kyphe

    “Unlike the GAU-8, the GSh-30-2 is braked, allowing the center of fire to be slightly offset from the centerline of the aircraft.”

    The brake which acts as deflector on the frog is not a left-right center line issue, but a nose dive issue caused by the vertical position which is significantly bellow the wing roots, causing a fulcrum issue (no pun intended … honest). Firing the gun without the device causes the aircraft to dip in flight.

    The Russians also have a 30mm aircraft Gatling cannon Gryazev-Shipunov GSh-6-30 which can also have a brake system.

    I believe the GAU-8 can fire pretty much the whole family of 30x173mm rounds the decision not to do so is logistical/doctrinal not a mechanical limitation. Just in case anyone thought this gun fired only propitiatory rounds.

    • Likvid

      Yeah, that always kinda bugs me – how people still keep pointing out the “limited selection of ammunition” for GAU8, whilst it’s 30x173mm standard calibre gun.

      Also I’m pretty sure GAU8 is hydraulically driven, not electrically driven as mentioned in article.

    • Warren Ellis

      I think the only rounds the GAU-8 can’t fire is the full on APFSDS 30mm round and that’s because of the possibility of the sabot damaging the feed mechanism, or getting sucked into an engine, when fired. But that’s about it.

  • Vhyrus

    But does it ‘BRRRRRTT’?

    *Watches video* Apparently it does. You’re hired.

    • Timmah_timmah

      /debate haha

  • gunsandrockets

    In form and function the Frogfoot is more equivalent to the old A-7D Corsair II than the A-10

  • Mack

    I wonder how much, if any influence, came from the plane that lost to the A-10. The YF-9.

  • 22winmag

    No wonder traffic to this once fine blog is on the decline.

    Every other article is about flashlights, knives, aircraft, howitzers, or just plain fluff.

    • No one

      *Literal worst poster on this site complaining about content quality.*

      You’ve disappointed us all Liberty, I mean, you did become a running joke your comments are so bad but, no one actually wanted you to come back and continue whining more then your average school girl per usual.

  • James Young

    I like it when TFB does articles on really big firearms

  • LazyReader

    This plane is good, but no A-10, it’s faster, more jet designed, and has a shorter range and the plane only carries 250 rounds of 30mm ammo, the A-10 carries 1,100.
    The A-10 was built from the ground up thanks to Pierre Sprey and his good people who talked with soldiers and pilots dedicated to the role of Close Air support. A survivable, reliable, lethal, simplicity of a plane.

    • wicapiwakan

      It’s a different plane designed for a different combat doctrine. The Soviets put a premium on speed and mobility for their forces, and maximized firepower even if it came at the cost of precision.

      Their entire doctrine was built around ending a war with NATO, win or lose, in a month or less. They realized that if they could do that, they had a chance. If the war dragged on longer, they had no chance as NATO’s population and industrial advantages would come to bear, as would the full might of the US Navy.

      Rather ironically, the Soviets during the Cold War found themselves in a rather similar strategic situation to the Nazis prior to Barbarossa. They would win quickly, or they would not win.

      • Tritro29

        That has no bearing to reality whatsoever. For the good part of the Cold War manpower, raw input and interdiction odds were on the USSR favour. The only conventional approach being left for Western Europe. Going fast wasn’t out of the scare that NATO would prevail, but that the escalation would be so high that a nuclear exchange would be unavoidable if the battle dragged on. Also Germany had a good Two years of warrying prior to being a punching bag for military bean counters. So no, going fast doesn’t mean what you think it means.

        • wicapiwakan

          The Soviets had more in the field, but NATO’s potential was significantly higher. The Soviets also couldn’t really hope to defeat the US Navy, but could delay them for a while.

          There was also the real worry that China would eventually jump in and stab the Soviets in the back, as there was no love lost between the two after Stalin died. The Soviets could not hope to defeat NATO and China at the same time.

          That said, NATO’s plan hinged around REFORGER, which was such a fantasy that it made Lord of the Rings look like a documentary. The Soviets planned on capturing as much of the REFORGER stocks as they could, using crack VDV and Guards units, and if that failed, they knew the exact location of every bit of it, and they had plenty of missiles and bombs to make sure no one got it.

          While the nuclear exchange was indeed a factor, both sides did make and maintain plans for a conventional war, and in that the Soviets are always pretty clear that they would be tapped out quickly in terms of logistics within a month or so. Keep in mind that the causality estimates from both sides were well into the millions even for a one month war.

          • Tritro29

            This is a late 1980´s fantasy. A self intoxicating fairy tale that is supported mostly by bad one liners out of B movies and Ray Ban Sunglasses. For one main reason. China was manhandled not once but twice. Once in 1969 and then again in 1979 by th PAVN. Stop smoking Red Dawn and Rambo 3. All wars between the two blocks were planned around gaining as much ground as possible before the nuclear exchange. Plus even in the best performance scenario in two to four weeks the Soviet troops would have been in Eastern France. And US troops in the Swamps of Poland. Really not the best way to abound nuclear strikes. US Navy? No, the US network of bases yes. Same deal as today.

      • XT6Wagon

        Its the way it is, because its a copy of the YA-9, which Russia believed the USAF would pick over the YA-10.

        • wicapiwakan

          Besides both of them being nimble twin engine CAS planes, the two have almost nothing in common, but sure, total copy.

          I bet you think the AK is a copy of the StG-44, too.

    • Uniform223

      “The A-10 was built from the ground up thanks to Pierre Sprey and his good people who talked with soldiers and pilots dedicated to the role of Close Air support. A survivable, reliable, lethal, simplicity of a plane.”

      > I have a seething contention for any comment that gives Pierre Sprey credit. The man rides on the coat tails of those greater than him and takes credit where none is due towards him. He uses his association with others as an attempt to prop up his own misguided, out of date, and ill-researched (if any was done by him at all…) agenda. He is a self-righteous, pompous, insulting A-hole to anyone who disagrees with him. When evidence (actual factual, researched, and validated) evidence is set forth to counter him, his only counter argument is; “its all lies and advertisements by defense contractors and manufacturers”. He WAS NOT and IS NOT (nor will he ever will be) the creator/designer of either the vaunted and successful F-16 and A-10 designs (the fact that he keeps taking credit for them makes my point). He has no aeronautical engineering background what so ever. He was a number crunching statistician; he was a defense analyst (and not a very good one then nor is he now) His involvement with the LWF program (which spawned the F-16 and in some cases the F/A-18) and the A-X program (which lead to the A-10) was merely peripheral at best.

      The men to ACTUALLY thank for the F-16 and A-10 are these men…
      F-16
      http://www.codeonemagazine.com/article.html?item_id=37

      A-10
      http://creationwiki.org/William_Curtis
      https://airandspace.si.edu/support/wall-of-honor/dr-william-m-curtis-iii

      It is sad that these two individuals are never mentioned when talking of the F-16 and A-10.

      I am pretty sure everyone here can agree that the M1 Abrams tank is one of the best and most proven MBTs of the late 20th century and even to this day it is a tough costumer to beat despite its age. Not according to Pierre Sprey… look at the date on the bottom of the first slide.

      http://pogoarchives.org/labyrinth/09/07.pdf

      The man knows NOTHING of air combat tactics or modern aerodynamics. The man will go on just about ANY forum just so he can vomit his stupidity to people equally as stupid (if not more so because they believe him…).

      He is a dumbass of colossal proportions. He claims that the F-15 is loaded up with junk and that radar and missiles are useless.

      Does he know that the F-15 have the a 104 to 0 kill ratio? Does he also know that the first kills by the F-15 (by the Israeli AF) were made by the F-15s by MISSILES? Does he also know that the VAST majority of recorded air to air kills made by F-15s have been done by missiles? Does he also know that the there has been a steady incline of missiles used to make air to air kills since the 60s?

      http://csbaonline.org/uploads/documents/Air-to-Air-Report-.pdf

      https://i.stack.imgur.com/lhIDl.png

      if you were to tell him that the most recent aerial victory (F/A-18E/F Super Hornet shooting down a Syrian Su-22) was done by a missile, he would most likely double down on his stupidity and make up a long winded excuses about conspiracies within the defense contracting/manufacturing world…

      The man is a self righteous ignorant F-tard. Want more proof? Here he is with a discussion/debate with an ACTUAL pilot. You can here the pilot chuckling in the background to many of Sprey’s comments.

      Further more the idiot (at this point you should know who I am referring to) believes that multi-role aircraft are a flawed design. Does the he know that the intent behind the F-16 was always to develop it into a multi-role fighter aircraft? Does he know that majority of designs and upgrades to modern aircraft are to give them more multi-role capability?

      Okay I think I put my point across about that Gojira (original Japanese pronunciation but more commonly known as Godzilla) F-tard. Now to the A-10.

      The A-10 is a good aircraft now. No one will dispute that. However in its inception there were many things about it by the ground attack community that were let downs (things you don’t often here…). Personally I know a retired USAF Lt. Col who flew the A-37 and A-7D in Vietnam. He helped train new pilots for the ground attack role and helped develop TTPs for the A-10 when it came to air-to-ground missions. Simply put it was a WW2 fighter technology in a 1970 airframe. There was nothing modern about it when it came out. The aircraft’s pitch to be simplistic was in some ways its downfall.
      When he heard about the A-X program he and some of his colleague in the A-7 community were expecting a better version of their already very capable A-7s. Instead they got an even slower aircraft with a large heavy cannon with no form of precision attack capability or advanced avionics. In training and exercises they were seeing that A-10s were getting shot down more often than their A-7s. This was primarily because the A-10s often had to make multiple attack runs on targets. The lack of modern avionics and precision attack capabilities of the A-10 only exacerbated this. They learned very quickly in Vietnam that making multiple passes was a “no no”. Strike hard and strike accurate then get out. Having to make multiple attack runs on a target increases the chances of getting shot down. He and a few others voiced their concerns but unfortunately congress wanted the USAF to have a simple attack aircraft. The A-10 had to wait until the late 80s and early 90s to get to where the A-7D already was in the mid 70s.

      Its funny that people will always talk up the A-10 but I find it ironic that the country that would seemingly need it most (Israel) has no interest in it. I am told this is because of their experiences in the Yom Kippur War. My old friend trained with Israeli ground attack pilots who survived the Yom Kippur War. When asked about the A-10 he said they would often shutter at the notion of flying A-10 into defended air space that they saw in the Yom Kippur War.

  • MrDakka

    I think Hughes Aircraft made a similar type of gun as the GSh-30-2; can’t recall if it was for the A10 or not

    • Tony Williams

      “I think Hughes Aircraft made a similar type of gun as the GSh-30-2”

      There was only one US Gast cannon that I know of: it was by General Electric, and called the GE-225. It was in 25×137 calibre. Never got beyond the prototype stage.

  • Ron

    For this type of application people need to stop getting wrapped around the axial about the gun. Guns are great for suppressing area targets and somewhat alright for large targets like soft skinned vehicles, but if you want to kill people you need to do what this does and put HE on and near the intended target.

  • Stephen Paraski

    The A-10 warthog was built around the gun. The air frame is the stock. We have the A-1- at Selfridge ANG Base north of Detroit.

  • clampdown

    They don’t carry anywhere near the amount of ammo that the A-10 carries.

  • Iblis

    I wonder if the same Gast principle could be applied to a widened double barrel magazine fed shotgun? Great Article!

  • Brett baker

    Thanks. Cool footage!

  • Ralph apmann

    Not interested

  • noob