M/71 Bomb effectiveness

[Kozality]

Apologies in advance if there's a thread on this elsewhere, I couldn't quite find one.

 

I've been doing low-level attack runs with the AJS-37 using high-drag bombs in CCIP mode and low-drag in DYK mode. In both instances, I feel like the damage done is negligible. Last night I dropped a slick of 16 M/17s over a column of enemy light vehicles (APCs and ZSU-23s) and watched over my shoulder as I had a good shack on the target. And yet the log showed....no kills. Whole path went up in explosions, and nothing.

 

I realize the M/71 is a light bomb (120kg about), but I'd expect to see more of an effect? I was hoping to see some more splash effect but more often than not I only get the occasional damage. Does this sound about right?

 

Thanks!

[Nealius]

I'm starting to wonder if blast damage is having some problems in 2.5. In 1.5.8 I could take out 8-9 vehicles with a slick of M/71HD. Since 2.5 I have been having problems taking out anything without direct hits with any bomb, including Mk82s.

[Zabuzard]

Only Viggen or other modules too? Like bombs from A-10? Then it probably would have to do with the engine.

[Nealius]

AV-8B. Mk81 and Mk82 don't seem to do much unless I get a direct hit. The Mk83 seems to pack a wallop, though.

[MBot]

Regardless of DCS' lack of fragmentation damage, I wonder why the real Viggen was never equipped with larger calibre bombs. How did they intend to drop heavy concrete or steel bridges with the weapons at hand?

[razo+r]

Regardless of DCS' lack of fragmentation damage, I wonder why the real Viggen was never equipped with larger calibre bombs. How did they intend to drop heavy concrete or steel bridges with the weapons at hand?

 

Maybe they used the RB-05 for that task?

[QuiGon]

Regardless of DCS' lack of fragmentation damage, I wonder why the real Viggen was never equipped with larger calibre bombs. How did they intend to drop heavy concrete or steel bridges with the weapons at hand?

 

IIRC the Maverick variant with the enlarged warhead (RB-75T) has been introduced for exactly this purpose.

[MBot]

RB-05 and RB75T warheads are still tiny when used against reinforced structures. Bridges are historically notorious for being extremely difficult to destroy. During Desert Storm, the USN dropped 34 LGB (1000lb or 2000lb) against bridges and only destroyed 3 spans. While I can see the RB-75T being useful against light structures, military bridges, pontoons or ferries, I wonder how they intended to cut the numerous major river crossings in Norrland or Lapland.

[Holton181]

...I wonder how they intended to cut the numerous major river crossings in Norrland or Lapland.

I believe it was suposed to be done by regular man planted bombs, dynamite, TNT, before the Russkies got close. Some railway bridges of the Malmbanan has boxes on strategic places so dynamite could be placed there when a conflict got close, then it was just to detonated them whenever the situation necessitated.

Edited February 24, 2018 by Holton181

[MBot]

I am sure most of the bridges would be blown by the Swedish Army, but in war things often don't go according to plan. Spetsnaz could sabotage the demolition or airborne assaults could capture intact bridges prematurely. Famously during WWII the Germans failed to blow a Rhine bridge at Remagen which the Allies managed to capture intact and exploit to great effect. The Germans then spent considerable efforts, mostly fruitless, to still drop it with artillery and air strikes. I think the Viggen would have been very well suited for such a contingency.

 

Also any bridges in Finland, which would have been key for Soviet offensives into Norrland, were only reachable by air strikes. I don't know what the official Swedish policy was regarding attacking targets outside its national borders. But I am pretty sure that Finish territory could not have been ignored during an invasion of northern Sweden, especially considering the heavy tilt on air power of the Swedish defensive doctrine. Attacking bridges in Finland would have been the equivalent of attacking transport ships in the Baltic.

 

As such I think it is very surprising that the Viggen lacked a heavy weapon to attack strong bridges. They even had a 500kg mine bomb for the Lansen. Adopting it for the Viggen surely would have been easy.

[renhanxue]

The 500 kg mine bomb was an anti-ship weapon. The 120kg m/71 bombs are mainly used for fragmentation effect over a larger area.

 

A capital M in the m/year designation indicates that the object in question belongs to the navy, by the way. The more you know! :V

[Freeroamer]

If only we could actually have Mk82s on the Viggen

[dimitrischal]

Rendering a bridge unpassable does not necessarily mean dropping all the spans. Damage on any span can mean the bridge is out for a respectable amount of time, almost surely unsuitable for armor.

I am also curious though about the absence of any larger warhead weapons on the viggen.

[theOden]

Bombs and rockets were regarded obsolete in the missile fanatic era of Viggen and F-4 Phantom birth years and Viggen was planned for as a missile carrier with secondary options being ARAK and bombs (napalm and heavy bombs were old A 32 Lansen stuff).

 

Your bridgekiller is the Rb 05 (and it sure packs a good punch in DCS too).

 

Small "virgo" bombs comes hand in hand with the low level profile and bigger Mk82 or Mk83's would become a hazard.

 

Had the Viggen been able to lock on a ground target, such as a bridge, loft bombing heavier ordnance could have been an option but in the missile era, missiles were considered the future.

 

And we all know how that turned out for the missile only Phantom's.

[MBot]

The 500 kg mine bomb was an anti-ship weapon.

 

But that wasn't its sole utilization, right? As a weapon optimized for blast damage it would have been useful in various situations to move large quantities of metal, concrete or dirt.

 

 

 

Another interesting fact I just found out about is that the m/56 used by the Lansen actually was the same British 1000lb bomb which was in service with RAF Harrier, Jaguars and Tornados. Makes me wonder even more why it wasn't put on the Viggen.

[QuiGon]

RB-05 and RB75T warheads are still tiny when used against reinforced structures. Bridges are historically notorious for being extremely difficult to destroy. During Desert Storm, the USN dropped 34 LGB (1000lb or 2000lb) against bridges and only destroyed 3 spans. While I can see the RB-75T being useful against light structures, military bridges, pontoons or ferries, I wonder how they intended to cut the numerous major river crossings in Norrland or Lapland.

 

Well, that was the swedish plan though. See here: https://forums.eagle.ru/showpost.php?p=3345117&postcount=15

[Farks]

"Med Invasionen I Sikte" does hint at a possible reason for why the Viggen was only equipped with light bombs. On page 22/23 (my translation):

 

The trend during the period in question was to prioritize smaller bombs, since these statistically required fewer aircraft sorties to sink a landing vessel...

 

It does also mention on page 39 that the transition to lighter bombs was indeed questioned during the time period.

 

But as the posts above explain, the swedish plans were indeed to target bridges with Rb 05's and Mavericks. The swedish version of the Maverick was modified specifically to work better against ships and bridges. It's also possible they planned to hit bridges with a mixture of ordinance, some aircraft firing missiles and other dropping bombs.

 

But of course it's also possible the air force perhaps misjudged these scenarios.

[microvax]

If you are asking for mk82, load rb05, it has like double the HE charge, closer to an mk83 then mk82 tbh.

[MBot]

I don't have the data for the RB05 and RB75T, but the regular AGM-65E/F/G has a 136 kg blast-fragmentation warhead containing 39 kg of explosives. I assume the RB75T has a similar (or the same) warhead. As a comparison, the Mk-82 contains 87 kg of explosives and the Mk-83 202 kg.

 

I have doubts whether the RB75T is able to seriously damage sturdy concrete or steel bridges. I am sure it works great against military bridges such as:

 

 

[Farks]

The Rb 75 was based on the A-version of the missile, with some seeker improvements. According to Arboga Missile Musuem, the Rb 75T weighed 295 kg compared to the 210 kg of the regular version. The Rb 05 had a 160 kg warhead.

[MBot]

The warhead of the RB75T is probably the same as the regular Maverick heavy blast-fragmentation warhead (WDU-24/B) though, right?

 

Do you know the amount of explosive of the Rb 05 warhead? I assume it is also a blast-fragmentation warhead because of its air-air role. So of the 160 kg total weight, probably around 50 kg of explosives.

[microvax]

RB75T is a swedish local developed minewarhead so high HE load explicitly for anti shipping and demolition.

The RB75T was a thing before the heavy warhead maverick warhead was even produced afaik.

 

 

RB05 afaik is nearly 160kg HE charge.

Edited February 28, 2018 by microvax

[Farks]

According to a forum post on soldf.com the Rb 75T had 135 kg of explosives in its warhead, but I don't know how reliable that info is.

[Kozality]

This is really interesting regarding the Rb-05 and -75 (seriously, the references are great) and confirms my suspicions a bit about the latter (that the Rb-75 in Swedish service wasn't really a CAS weapon).

 

But any insight into the M/71? I've seen some people reply that they're having issues with the Mk8* family. Are the M/71s just not used?

[microvax]

For light/unarmored area targets the m71 work pretty well imho.

I attack coloumns of unarmored vehicles, multi unit sam sites etc with it.

 

The rb75 itself is an anti tank weapon and intended to be used as one, the rb75T not so much.