Tank Busting Armaments... Whats The Best Setup???

[Tony Williams]

There were only a handful of NW European "tank battles", and these generally consisted of the German's being on the defensive, in which case aircraft had a hard time spotting the tanks until battle was engaged, and then it was difficult to attack them because of FF risks. When the German's did attack, it was usually under cover of bad weather.

In tne Mortain batttle, Allied fighter-bomber claimed 252 tanks destroyed in a four-day period. In the one month of fighting in the Ardennes Salient (which was more difficult country - hilly and wooded - and the weather was initially bad) they claimed 324 tanks and 89 other armoured vehicles destroyed. Clearly, they were able to see and attack them. Unfortunately their claims for hits proved to be wildly optimistic.

So far, everything you've presented represents the British experiance with the 7.62cm/3" RP's, a very different weapon than the 5" HVAR. Amoung other differences, the RP's were known to be much less accurate than the HVAR's both because of the fin design and the much weaker rocket engine and thus slower acceleration, and less effective because of the much smaller payload.

Can you quote your source for that? I have no data on the HVAR's accuracy, but your information on payload is incorrect. The British RPs carried a 60 lb warhead, which contained 14 lb of TNT. The HVAR's 40 lb warhead carried 7.7 lb of HE.

British RP's were not even developed for ground attack, they were intended for AA use and then adapted to ground attack because they were plentiful.

Wrong again - the 3 inch rocket motor was designed for an AA weapon, but the addition of the 60 lb HE and 25 lb AP warheads was for aircraft use only. Incidentally, the HVAR reached a velocity of 390 m/s compared with the 60 lb RP at 350 m/s (the 25 lb RP hit 460 m/s) so there wasn't a huge difference ballistically.

Finally, I'm not saying that in terms of the pure accuracy a 5" HVAR was anything close to as accurate as a cannon. If the plane had the time and freedom to setup and attack, the cannon were much more accurate, but doing so in W. Europe after D-Day was nearly suicide. For the kind of attacks that were being conducted in W. Europe in late '44 and '45, namely 300 mph single passes into heavily defended positions, the HVAR was probably more effective. At such speeds with a cannon you would get maybe two rounds off, where you could fire up to 8-10 rockets.

On the contrary, the much flatter trajectory and shorter time of flight of cannon shells made them much easier to line up and quicker to use. RP firing needed more careful preparation if you were going to stand much chance of a hit. Yes, you could volley RPs to make up in quantity what you lacked in accuracy, but even the careful, single-aimed shot approach of the British big-gun planes allowed them to fire four times on each attack (i.e. 8 shots form the Hurri's 40mm guns), which was enough to hit the target.

Tony Williams: Military gun and ammunition website and Discussion forum

 

[Anonymous]

There were only a handful of NW European "tank battles", and these generally consisted of the German's being on the defensive, in which case aircraft had a hard time spotting the tanks until battle was engaged, and then it was difficult to attack them because of FF risks. When the German's did attack, it was usually under cover of bad weather.

In tne Mortain batttle, Allied fighter-bomber claimed 252 tanks destroyed in a four-day period. In the one month of fighting in the Ardennes Salient (which was more difficult country - hilly and wooded - and the weather was initially bad) they claimed 324 tanks and 89 other armoured vehicles destroyed. Clearly, they were able to see and attack them. Unfortunately their claims for hits proved to be wildly optimistic.

Just because they could see and attack them does not mean these attacks were nearly as favorable as attacks on tanks out in the open in the N. African desert or on the Russian stepps. The fact that so few of the tanks attacked were actually destroyed can be looked at either as supporting the idea that the method was inferior OR that the conditions were not as favorable to success.

Clearly in Korea F-51 pilots claim consistant hits with salvo's of 4-6 HVARs against T-34 tanks. Skyraider pilots claim 2-4 rockets was enough to just about gaurantee a hit on a tank as long as it was in the relative open. And in both cases attacks were carried out at the fastest possible speed.

Finally, I'm not saying that in terms of the pure accuracy a 5" HVAR was anything close to as accurate as a cannon. If the plane had the time and freedom to setup and attack, the cannon were much more accurate, but doing so in W. Europe after D-Day was nearly suicide. For the kind of attacks that were being conducted in W. Europe in late '44 and '45, namely 300 mph single passes into heavily defended positions, the HVAR was probably more effective. At such speeds with a cannon you would get maybe two rounds off, where you could fire up to 8-10 rockets.

On the contrary, the much flatter trajectory and shorter time of flight of cannon shells made them much easier to line up and quicker to use. RP firing needed more careful preparation if you were going to stand much chance of a hit. Yes, you could volley RPs to make up in quantity what you lacked in accuracy, but even the careful, single-aimed shot approach of the British big-gun planes allowed them to fire four times on each attack (i.e. 8 shots form the Hurri's 40mm guns), which was enough to hit the target.

The Hurri was not able to make a 300-350 mph pass. If it were able to do so, it would have sufficient time to take one, maybe two shots at the target, which would mean maybe 4 rounds fired. The HVAR armed plane could release a salvo of 4-10 rockets in the same pass.

As for your velocity of rocket figures, I do not have specific figures, but I do have footage, and there is absolutely no question that the HVAR's accelerate much faster than the 3.5" rockets. I have footage from P-47's and from Tempests and Hurricanes firing rockets, and it is very easy to see. And also you imply that the HVAR's were extremely wild and dropped tremendously in their flight path, but the footage does not show this. In a salvo of 8 rockets, typically one or two go wild, but the rest go pretty strait.

The velocity figure I have for the HVAR is 414.5 m/s, but the time to reach max. velocity is a critical difference. The "HV" in "HVAR" is there for a reason, and it is specifically in comparison to the earlier 3.5 inch motored versions.

I'll have to find the reference, but the figure I've seen for the payload of the HVAR is 20 lbs of HE. But you have to admit the larger warhead you are specifying for the RP's coupled with a much smaller rocket imply much slower acceleration as well as a lower final velocity.

All sources I've seen indicate the "Holy Moses" rockets hit much harder than the RP's. RP's were abandon after WWII as ineffective, but HVAR's were still in use well into the 1960's.

=S=

Lunatic

 

[Anonymous]

Here's a source on the 3.5 inch British rockets vs. the 5" HVAR:

Stats 3.5" Rocket:
Weight: 25kg / 55lbs
Length: 1397mm / 55ins
Warhead: 9kg / 20lbs solid steel or explosives
Speed: 358m/s / 1175f/s

Stats HVAR:
Diameter: 5"
Weight: 63.5kg / 140lbs
Length: 1829mm / 72ins
Warhead: 25kg / 55lbs
Speed: 419m/s / 1375f/s

http://www.microworks.net/pacific/armament/rockets.htm

After searching rather extensively, I'm pretty convinced that the warhead figures above are accurate, and that they are included in the total weight of the rocket.

There was a ~60 lbs warhead on a 3.5" rocket, it was the same warhead as mounted on the 5" HVAR (actually 55 lbs), but you are selectively mixing the stats on the 5" FFAR (5 inch warhead on 3.5" rocket) with the velocity of the strait 3.5" rocket and it's 20 lbs warhead. The 5" FFAR was slow and front heavy, which made it inaccurate.

=S=

Lunatic

 

[Tony Williams]

The fighter-bombers wouldn't launch an attack unless they thought they could hit - attacks were very dangerous due to the very effective German light flak. In fact, that flak in distracting the pilots may well have contributed to the problems in making accurate rocket attacks. This extract from 'Flying Guns – World War 2: Development of Aircraft Guns, Ammunition and Installations 1933-45' explains the problems with the British RP, but in principle any rocket suffered from these to a greater or lesser extent:

"This fall in accuracy experienced in action may be attributed to the curious trajectory of the RP, which first dropped below the line of sight and then accelerated as the rocket motor took effect before it dropped again. Because of this it was generally desirable to fire them at a range of between 900-1,800 m. They were also very susceptible to side winds, with a mere 15 km/h wind being enough to miss the aiming mark by nearly 5 m, and the aircraft had to be absolutely steady at the instant of launching. This meant that a pilot needed a very cool and calculating head to ensure reasonable accuracy, something that was difficult to achieve in the heat of battle. It is worth noting that high-velocity cannon did not suffer from this problem, so would have experienced a much less significant fall-off in accuracy under combat conditions. "

I don't know of any 3.5 inch rocket. The British RPs were known as 60 pdr or 25 pdr Rocket Projectiles, depending on the warhead, and used a 3 inch diameter motor. There were two USAAF rockets: the 4.5 inch and the 5 inch HVAR. This is the info in FG:WW2.

"The two RPs used by the USAAF had different histories. The 4.5" version originated from a 1940 request from the Ordnance Department to the National Defense Research Committee for help in developing a rocket primarily for use in aircraft. The availability of British research speeded the task so the first prototype was tested at the end of 1941. Somewhat bizarrely, the calibre of 4.5" (114 mm) was determined broadly by the specified warhead size and 330 m/s velocity, but specifically by the availability of surplus fire extinguisher tubes of that size! Unlike the British RPs, the 4.5" (designated the M8) had folding fins as they were launched from tubes. After significant problems with propellant quality, the M8 entered service in December 1943. In service, the tube-launching was found unnecessary and imposed drag penalties, so first the zero-length launcher from the USN's 5" (127 mm) HVAR (high velocity aircraft rocket) was utilised, then the HVAR itself was adopted, although the M8 remained in service alongside. The M8 weighed 18 kg and the warhead carried 2.3 kg of HE and reached 260 m/s. The HVAR, which achieved 390 m/s, weighed 63 kg and carried 3.5 kg of HE."

The Hurri attacked at around 250 mph. If its speed went up to 300, it could have got in three shots. The Tsetse with 6 pdr gun was very fast yet in practice could still get of four shots against a tank-sized target, with a virtually guaranteed hit.

I note that in describing the results in Korea you refer to 'claims'. Please note that WW2 claims against tanks were found to be overstated by 1,000% when the results were examined on the battlefield.

Tony Williams: Military gun and ammunition website and discussion
forum

 

[Anonymous]

Every source I've seen refers to the British supplied rockets as being of 3.5" diameter. This may well have been the outside diameter, with a 3" rocket being inside the 3.5" casing. That'd just be a standards and nomenclature issue.

Yes, I've seen references to the 4.5" FFAR (I think it was designated FFAR) as well, and perhaps this represents a different warhead on the same 3.5" rocket? In any case these were the tube fired things and they were a failure.

The US nomenclature for the British type 3.5" rocket is FFAR (Forward Firing Arial Rocket), and this term is also used for the 5" version, which had the same rocket motor. The 5" FFAR was found to be unsuitable by the USN because of it's inaccuracy and low speed, but perhaps the British used their own variation of this anyway? In any case, to support the 5" warhead the USA developed the HVAR.

I think if you investigate you will find the "60 pounder" was in fact refering to the total weight of the warhead, not HE payload. If it did refer to just the HE payload, that'd mean a warhead weighing something on the order of 150+ lbs!

I agree conditions were different in W. Europe than in N. Africa and the Stepps of Russia, in many ways, resulting in different results.

As for the claims for Korea, there is often film to back it up (I have lots of 8mm Korean war Skyraider footage and combat assement photos). One thing is clear in Korea, hitting the tank with an HVAR was often not enough to take it out of action. Most attacks were to the sides, and the most frequent damage damage was to the tracks or wheels.

=S=

Lunatic

 

[the lancaster kicks ass]

I think if you investigate you will find the "60 pounder" was in fact refering to the total weight of the warhead

that's proberly true, the Grand Slam weighed 22,000lbs but "only" had a 9,135lb warhead............

 

[cheddar cheese]

MOAB all the way...

 

[Tony Williams]

Every source I've seen refers to the British supplied rockets as being of 3.5" diameter. This may well have been the outside diameter, with a 3" rocket being inside the 3.5" casing. That'd just be a standards and nomenclature issue.

The diameter of the body of the RP may have been 3.5 inches (although the diameter of the 60 lb HE warhead was considerably larger), but I've never heard it referred to as a '3.5 inch rocket'. It is generally known as the RP (for Rocket Projectile), sometimes the 3 inch RP or 3 inch rocket, for the diameter of the motor.

Yes, I've seen references to the 4.5" FFAR (I think it was designated FFAR) as well, and perhaps this represents a different warhead on the same 3.5" rocket? In any case these were the tube fired things and they were a failure.

Why would it use the British 3 inch motor? It was American, not British, and was of 4.5 inch diameter anyway. FFAR stands for 'Folding Fin Aircraft (or Aerial, or Air-launched) Rocket' - the fins have to fold to fit into the launch tube, they spring out on launching - but this term was I think first coined to describe postwar rockets in multiple pods (which have been highly successful), not the 4.5 inch.

The US nomenclature for the British type 3.5" rocket is FFAR (Forward Firing Arial Rocket), and this term is also used for the 5" version, which had the same rocket motor. The 5" FFAR was found to be unsuitable by the USN because of it's inaccuracy and low speed, but perhaps the British used their own variation of this anyway? In any case, to support the 5" warhead the USA developed the HVAR.

Re FFAR - see my comment above; ever heard of a backward firing aerial rocket? . The term FFAR does not apply to any British rockets of this period - they all had fixed fins. I don't know anything about a 5" FFAR; if there was such a thing it wasn't British AFAIK.

I think if you investigate you will find the "60 pounder" was in fact refering to the total weight of the warhead, not HE payload. If it did refer to just the HE payload, that'd mean a warhead weighing something on the order of 150+ lbs!

If you read my earlier post you will see that's exactly what I said; a 60 lb warhead with 14 lb of TNT.

I agree conditions were different in W. Europe than in N. Africa and the Stepps of Russia, in many ways, resulting in different results.

As I've said, the results were different because the weapons were different. The Russians did have RPs (in fact they were the first to use them) but found them too inaccurate to be effective against single tank targets. They PTAB cluster-bomb was their best anti-tank weapon, but the British and Americans had nothing like it.

As for the claims for Korea, there is often film to back it up (I have lots of 8mm Korean war Skyraider footage and combat assement photos). One thing is clear in Korea, hitting the tank with an HVAR was often not enough to take it out of action. Most attacks were to the sides, and the most frequent damage damage was to the tracks or wheels.

Camera gun footage which is released to the public tends to be selected to show the successes - which may be only a very small percentage of the attacks. So it does nothing to prove how accurate such rocket attacks were in general. And I've never argued that rockets couldn't hit tanks, just that they rarely did in the WW2 timeframe which is what we're talking about, so made an unsatisfactory anti-tank weapon (although they were very destructive against area targets).

Tony Williams: Military gun and ammunition website and Discussion forum

 

[Anonymous]

The diameter of the body of the RP may have been 3.5 inches (although the diameter of the 60 lb HE warhead was considerably larger), but I've never heard it referred to as a '3.5 inch rocket'. It is generally known as the RP (for Rocket Projectile), sometimes the 3 inch RP or 3 inch rocket, for the diameter of the motor.

Well, the point is it was the same rocket section. All the sources refer to the 3" or 3.5" rockets as having been supplied by the British.

Why would it use the British 3 inch motor? It was American, not British, and was of 4.5 inch diameter anyway. FFAR stands for 'Folding Fin Aircraft (or Aerial, or Air-launched) Rocket' - the fins have to fold to fit into the launch tube, they spring out on launching - but this term was I think first coined to describe postwar rockets in multiple pods (which have been highly successful), not the 4.5 inch.

I don't know why, other than that there were a load of British made rocket sections available.

Re FFAR - see my comment above; ever heard of a backward firing aerial rocket? . The term FFAR does not apply to any British rockets of this period - they all had fixed fins. I don't know anything about a 5" FFAR; if there was such a thing it wasn't British AFAIK.

Well, the only source I've seen defining it defines it as "Forward Firing" but you could be right. There could also have been research into downward firing rockets.

If you read my earlier post you will see that's exactly what I said; a 60 lb warhead with 14 lb of TNT.

My applogies, I misread that. But you also say the HVAR warhead was 40 lbs with an ~7.5 lbs HE load where data I've found says 55 lbs with an ~20 lbs HE load.

As I've said, the results were different because the weapons were different. The Russians did have RPs (in fact they were the first to use them) but found them too inaccurate to be effective against single tank targets. They PTAB cluster-bomb was their best anti-tank weapon, but the British and Americans had nothing like it.

Russian RP's were tiny by comparison to an HVAR. In fact I think they were small even by comparison to a British 3" RP.

Camera gun footage which is released to the public tends to be selected to show the successes - which may be only a very small percentage of the attacks. So it does nothing to prove how accurate such rocket attacks were in general. And I've never argued that rockets couldn't hit tanks, just that they rarely did in the WW2 timeframe which is what we're talking about, so made an unsatisfactory anti-tank weapon (although they were very destructive against area targets).

The footage I have was never released to the public. I have the entire stock of guncam footage from my Father's attack squadron 1951 and 1952 tours. He was the squadron CIC officer and took a lot of photos from his plane's cameras, and some 8mm footage from a wind up camera he kept in the cockpit, though often it's from too high to make out much detail. I have located several films of rocket attacks on tanks, but only in a few of them are the results clear. Often the smoke and/dirt (often hard to tell the difference) in the air makes evaluation difficult within the short period of the film clips. I have a good number of shots of tanks that have been destroyed, but it is hard to tell exactly how they were destroyed. And I have a large number of before/during/after photos of bridge attacks.

In the end though, I have to go back to his statements that firing rockets one at a time, you'd probably hit the tank within three shots, and a salvo of 4 rockets (fired in 2's) was enough to hit a tank well over half the time.

=S=

Lunatic

 

[the lancaster kicks ass]

MOAB all the way...

NO!!!!!

 

[cheddar cheese]

Hell yeah, Go USA!

 

[the lancaster kicks ass]

NO The Grand Slam's a symbol of everythig that's good about Britian!!

 

[cheddar cheese]

What, Big, fat and heavy? I think not

 

[the lancaster kicks ass]

no, sleek, fast, well buit...............

 

[cheddar cheese]

British items are famed for their lack of build quality, only behind the Italians...

 

[Anonymous]

British items are famed for their lack of build quality, only behind the Italians...

Leading up to WWII, the British reputation for quality was quite good. During WWII they had to cut corners to maximize quantity, and they seem not to have been able to completely recover from that.

They still eat Kidney pie, something you would normally only eat in the hardest of times.

=S=

Lunatic

 

[Nonskimmer]

British items are famed for their lack of build quality, only behind the Italians...

I think the politically correct term is "functionality".

 

[cheddar cheese]

Kidney pie is NOT nice...

 

[Maestro]

You're wrong, CC. Italian items are worst. British items are great ! Only think about all the great planes Britain built : Spitfire, Hurricane, Tempest, Lancaster (or more recently) the Harrier. Or the great cars : Rolls-Royce (I know it was bought out by BMW at the end of the 90s) and Benkley (or Bentley, can't remember).

 

[Nonskimmer]

Hey Maestro, didn't Bomber Harris especially like the Canadian built planes for quality?

(back me up here! )