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T40/M17 "Whizbang": More Bang For Your Buck


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39 members have voted

  1. 1. Would You Like This Tank?

    • Yes
      36
    • No
      1
    • Maybe / I Don't Know
      2
  2. 2. If Added, What BR Should It Be?

    • 3.7
      1
    • 4.0
      4
    • 4.3 (Same as "Calliope")
      24
    • 4.7
      8
    • I Don't Know / Don't Mind
      2
    • Other (Please Comment)
      0
  3. 3. If Added, How Should It Be Available To Players?

    • Researchable
      13
    • Premium
      13
    • Event / Tournament
      3
    • Squadron Reward
      7
    • I Don't Know / Don't Mind
      3
    • Other (Please Comment)
      0
  4. 4. Which Variant(s) Of The Whizbang Would You Like To See? (Multiple Choice)

    • M4 Sherman (Rarer Service Model)
      11
    • M4A1 Sherman (Main Service Model)
      34
    • M4A2 Sherman (USMC Trials Prototype)
      16


The T40 "Whizbang" was a limited-standard rocket-equipped variant of the M4 and M4A1 Sherman, developed alongside the T34 "Calliope" as a replacement for the early, awkward Mk.5 "Cowcatcher" system. Like the "Calliope", and unlike the hull-mounted "Cowcatcher", the T40 was affixed above the Sherman's turret on two arms mounted to the turret sides, with elevation and stability provided by another arm linking it with the main 75mm gun, which could be fired safely while the launcher was mounted. Unlike "Calliope", the "Whizbang" system suffered delays in testing and missed D-Day, then had to be withdrawn from the Ardennes due to an unexpected German tank push, resulting in the system only seeing significant combat in the Italian theatre. With a set of 20 183mm T37 rockets, based on the "Mousetrap" anti-sub rocket, the destructive power of the "Whizbang" is far in excess of the "Calliope", each of the 20 rockets being equipped with the same 15kg Torpex warhead as the "Hedgehog" spigot mortar.

 

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History:


Ahead of the Normandy landings, the US Army decided it needed a tank-based form of rocket artillery with which to deal with the German fortifications they were bound to encounter in France and beyond, and from that point on the Sherman tank became the base vehicle for a dizzying number of rocket systems, from externally-mounted rockets to internally-mounted revolver rockets and even a rocket launcher in place of the main gun. This impressive variety of models began with a humble design, which placed a box launcher for T37 rockets in front of the hull, held on a pair of arms which provided elevation. The system, dubbed "Cowcatcher", proved too awkward in its hull mount to be worth pursuing as a production vehicle, but the firepower was attractive to Army officials, so prototyping continued with a turret-mounted arrangement. Eventually, this resulted in a design very similar to the T34 "Calliope", although that tank used 60 110mm M8 rockets whose launch tubes had been welded together, rather than a single box launcher divided into 20 rectangular tubes for 183mm rockets. Though some "Whizbangs" used an M4 as the mount, and M4A2s were trialled (but, like the M4A2 "Calliope", not accepted) by the USMC, most of the tanks converted were M4A1(75)s, which also served in small numbers as the mount for the T34E1 "Calliope". 

 

image075.jpg

The first rocket Sherman, "Cowcatcher".

 

Part of the reason T40 was pursued as a project was the much more powerful warheads on the rockets compared to the "Calliope": although it was only 73mm larger in calibre, thanks to its 15kg warhead it had just over 6.5 times the weight of explosive. The T37 rocket was a land-based variant of the Navy's "Mousetrap" rocket, itself an American variant on the famed "Hedgehog" spigot anti-submarine mortar, replacing the spigot system with a rocket motor to reduce the stresses on the launch vessel -- as a result, the warhead was capable of sinking a submarine in one hit and found great success in anti-fortification roles, its greater explosive mass also ensuring that its anti-armour capabilities were much better than the "Calliope", which struggled against the German tanks of 1944-1945. Both "Calliope" and "Whizbang" were originally planned to land with the other tanks on D-Day and provide heavy fire support, but both systems were delayed in testing and in the end were never used in this role. Although hundreds of both mounts had been shipped to the UK and several M4s of the 70th Tank Battalion had been fitted with T40s, concerns about the tanks' stability on the landing craft, combined with the issue of the "Whizbang" launcher blocking the turret hatches, resulted in the plans being called off. Some of the 70th's M4s made it to the beaches with the mountings for the T40 still installed without a launcher, which would have allowed the surviving vehicles to be rearmed with the full "Whizbang" system once safely on solid land. 

 

image077.jpg

An M4A2 "Whizbang" trialled by the USMC.

 

It's unclear whether the 70th ever fully armed their "Whizbang" Shermans, or if they simply dismantled the mountings after landing, but small numbers of T40s saw combat in north-west Europe in 1944 alongside their similarly rare siblings, the T34s. The large, extremely explosive rocket rack made them vulnerable to close combat with German tanks, especially as these were 75mm Shermans, so the group of "Whizbangs" in the Ardennes was recalled after the Germans made a push with Panther tanks, against which the rocket-equipped Shermans would have fared poorly. As German armour was relatively light in Italy, save for the notable exception of some Ferdinand heavy tank destroyers, after their withdrawal from the Ardennes, the Whizbangs were sent to Italy, where they saw almost all of their combat. Another version of the "Whizbang" used a shortened version of the launcher atop an unarmed Sherman turret, but this did not go into production. Logistical and operational issues meant that neither of the rocket Shermans that saw combat service actually did as much fighting as the US Army had planned, but like its sibling, the "Whizbang" is significant as one of the most powerful rocket-armed tanks of the war. 

 

The T40 Rocket Mount & T37 Demolition Rockets:


A large steel box divided into twenty rectangular launch tubes, the T40 mount protected its explosive contents from enemy fire by enclosing them in armour 12.7mm-thick, including two hydraulically-operated doors at the front of the box, which enclosed and protected the fronts of the tubes when the rockets were not being launched. Since the T40 has a much shorter range than "Calliope", these armoured doors could deploy while the vehicle is moving quickly, since it's unlikely to be useful as a weapon fired on the move due to its low velocity. The system could elevate as high as the Sherman's own 75mm gun, 25 degrees, and could depress to 5 degrees despite its position low over the turret roof. Because they were a simple modification of an anti-submarine weapon, the T37 rockets had a range of just 210m; an experimental rocket, T57, installed the rocket motor from the "Calliope" and had a range of 1km, but these were apparently never used operationally.

 

While the severe drop of the rockets severely reduced its effective range, hence the T40s' quick withdrawal from the advancing Panthers in the Ardennes, it also enabled it to arc shots over cover such as hills and buildings, which meant it could land the hefty 15kg warhead behind enemy defences if it got the positioning right. In the context of War Thunder, mastering the drop of these rockets will give players a way to totally annihilate a tank by landing an antisubmarine warhead on their thinly-armoured roof, so long as they can get close enough to use them. The 15kg Torpex warhead is almost three times as powerful as the 5.8kg of filler in the KV-2's HE shell, and just under 3kg heavier than the legendary "Petard" spigot mortar fired from the Churchill IV AVRE, so its killing power against tanks close enough to hit with it is undeniable. The downside, of course, is that in the case of an ammo detonation the entire 20-round launcher would be jettisoned from the tank, leaving it with just its 75mm gun; larger-calibre guns or those firing shells with a lot of explosive filler would simply detonate the entire rack, wiping out the turret crew and in most cases taking the tank out with them.

 

For balance reasons, I'd recommend both the explosive power of the rockets and their potential to kill their carrying tank be reduced. It should have greater killing power than the KV-2's shell, on account of the real thing being three times as powerful, but not so much that it could kill a tank without either hitting it or landing the rocket next to it. Likewise, the launcher should probably burn up and eject from the tank when the rockets are detonated by medium-sized tank cannons (say, 50-75mm guns, and the Soviet 76mm), lose the ammunition but not detonate when shot with smaller guns, and chain-explode when hit by larger cannons (US 76mms, 17-Pdr, 88mm guns, etc.) The short range of the launcher, combined with the prevalence of guns that can at the very least cause it to burn up and be ejected at this tank's likely BR range, means that it's unlikely to be able to abuse the weapon too much -- if it rounds a corner to attack a trio of tanks, it may well be able to kill them with just a few rockets but one of those three tanks is just as likely to either kill its gunner or take out the launcher before it can kill them all. One lucky shot from a large enough gun is all it takes to put an end to the T40's reign of terror, so it would be forced to play carefully and plan its moves to avoid enemy fire, vastly reducing its ability to be obnoxious and aggressive by rushing a point and saturating it with rockets. For this reason, I think it's a more balanced vehicle than its impressive warhead would suggest -- situationally very good, but also a lot more vulnerable than an ordinary M4A1. The "Whizbang" experience would, I imagine, be very much a case of "Live by the rocket, die by the rocket."

 

Specifications (7.2-Inch Demolition Rocket T37):

 

E2M5JU6.png


Length: 890mm

Diameter: 183mm

Weight: 28kg

Warhead: 15kg Torpex HE

Speed: 110 mph (180 kph; 49.17 m/s)

Range: 210m

 

Specifications (T40 "Whizbang"; M4A1 Base):

 

M17_2-e1555317335973.png

 

Length: 6.27m

Width: 2.62m

Height: ~3.65m (the launcher is about 1/3 of the Sherman's height)

Weight: 38.1 tons

Crew: 5 (Commander, Gunner, Loader, Driver, Hull Gunner)

Hull Armour: 19.5-50.8mm front, 38.1mm sides and rear

Turret Armour: 50.8-76.2mm front, 50.8mm sides and rear

Rocket Pod Armour: 12.7mm sides, floor, roof and forward doors

Main Armament: 1x 75mm M3 cannon (90 rounds)

Gun Traversal: -12 to 18 degrees elevation, 360 degrees turret traverse (<24 deg/sec)

Rocket Traversal: -5 to 25 degrees elevation, no horizontal traverse

Secondary Armament: 1x 7.62mm Browning M1919 MG (hull-mounted)

Engine: Continental R975-C4 (400hp at 2400 rpm)

Max Speed: 23.75 mph (38 kph)

 

Its Place In War Thunder:


The T40 "Whizbang" has the potential to fit a few different roles in the game, thanks to its rockets providing both a major advantage and disadvantage to the tank. For one, it could be a Premium sold alongside its sibling, "Calliope", or an Event vehicle. It could be an interesting WWII-era Squadron Reward to work towards, too, since although its downsides may make it too unappealing to really excel as a Premium or Event vehicle, as something with a degree of meme value it would probably be well-suited as a vehicle to work towards with friends and fellow community members. The difficulty of balancing the vehicle makes me wary of making it one of these scarce reward vehicles, nor one that has to be paid for, since the money and/or effort put into obtaining it means that making significant balancing changes risks being met with backlash from owners. With more rocket-armed vehicles entering the game since the Type 60 SPRG (C) ushered in a new age of rocket tanks in War Thunder, there's potential now for a researchable rocket option at a lower tier, available to all players in the regular US tree. With the M4A2(75) being dropped from 4.3 down to 3.7, there's now a gap in the Sherman line which the "Whizbang" could potentially fit, its powerful rockets simultaneously making it more capable at killing tanks than the other 75mm Shermans and more likely to be killed itself, since its explosives don't care what they blow up. With the extreme drop and short range to its rockets, the "Whizbang" could serve as a good trial run for more extreme vehicles like Churchill IV AVRE "Petard" and the Matilda Hedgehog, regardless of how it becomes available in the game. An interesting form of rocket tank unlike any we've seen so far, but built on a much-loved and reliable chassis, the T40 "Whizbang" would be an exciting addition to the game.

 

I hope you like this tank, and I look forward to hearing from you in the comments!

 

More Pictures:

 

Spoiler

 

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A colour photo of an M4A1 "Whizbang", clearly showing its mounting system and its armoured doors.

 

THbscY1.jpg

A colour photo of an M4A1 "Whizbang" next to an M4 version.

 

t40whizbang.jpg

Another M4A1 "Whizbang" with similar camo to the one above.

 

image077.jpg

A Marine trials M4A2 "Whizbang" at Fort Knox.

 

image078.jpg

The same tank from behind.

 

t40+and+t34.jpg

The USMC's M4A2 "Calliope" and "Whizbang" prototypes during trials.

 

8g93iBH.jpg

A T40-armed M4A1 with M10 aircraft triple mounts of the M8 rocket used by "Calliope" installed instead of its usual T37 rockets.

 

image076.jpg

The prototype "Short T40", which lacked a gun and never saw production.

 

image075.jpg

The "Cowcatcher", which used the same rockets but in a hull-mounted box.

 

 


Video Of The T40:

 

Spoiler


 

A propaganda / training film of the T40 "Whizbang", which unfortunately has only survived in very poor quality. The firing demonstration starts around 1:58, and around 2:28 you can see just how extreme the drop of the rockets are. 4:00 shows the rocket rack being jetissoned.

 

A training film, with mostly the same footage as the prior film, but in slightly better quality. Previous timings should still apply to this video, which has more footage. At 14:58 you can see the T37 rockets being prepped for loading. 16:10 shows a closeup of the tank firing its rockets at close to full elevation; when the angle changes to show the resulting explosion, the T40's short range is pretty clear.


 

 

Sources:


M4 Sherman: Rare Photographs from Wartime Archives Plus Specially Commissioned Colour Illustrations, by Pat Ware (available online here)

Sherman M4 Medium Tank: The War Machines, by John Christopher (available online here)

World War 2 In Review: Sherman Medium Tank M4, Issue 1, by Merriam Press (available online here)

US Amphibious Tanks of World War II, by Steven J. Zaloga (available online here)

US Marine Corps Tanks of World War II, by Steven J. Zaloga (available online here)

Armored Attack 1944: U.S. Army Tank Combat in the European Theater from D-Day to the Battle of the Bulge, by Steven J. Zaloga (available online here)

https://www.us-militaria.com/vehicules/chars/tank-sherman-modifies/

https://erenow.net/ww/armored-attack-1944-us-army-tank-combat-european-theater/2.php

https://en.wikipedia.org/wiki/T40_Whizbang

https://en.wikipedia.org/wiki/7.2-Inch_Demolition_Rocket

https://en.wikipedia.org/wiki/Mousetrap_(weapon)

https://en.wikipedia.org/wiki/Hedgehog_(weapon)

http://www.tanks-encyclopedia.com/7-2in-multiple-rocket-launcher-m17-whiz-bang/

https://en.wikipedia.org/wiki/M4_Sherman_variants#US_M4_sub-types

https://www.militaryfactory.com/armor/detail.asp?armor_id=221 (source is on T34 "Calliope" but has information on T40 "Whizbang")

https://www.army.mil/article/223118/ria_self_guided_tour_the_experimental_72_in_multiple_rocket_launcher (as above)

https://en.wikipedia.org/wiki/T34_Calliope (used for information on the "Calliope" for comparisons)

http://www.tanks-encyclopedia.com/ww2-us-calliope/ (as above)

https://en.wikipedia.org/wiki/M8_(rocket) (as above, specifically for armament comparison)

https://en.wikipedia.org/wiki/152_mm_howitzer_M1938_(M-10) (used to compare KV-2's shells with T40's rockets)

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Open for discussion. :salute:

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+1 from me, I want more rocket tanks in game. Gib!

 

Though, I do have a semi unrelated question, I remember reading about an early atgm panzer IV, though I can't find anything now, was I duped?

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