HVAR vs ROCKET

[Washing Machine Charlie]

Hello all,

I was reviewing some old threads about torpedo troubles, bombs, and delivery systems, which caused me to wonder how much of a role did rockets play in the reduction of torpedo use?

I've read where rockets were considered equal to 5" guns and a destroyer/light cruiser broadside. True?

I've always loved reading about the part of the Pacific War, when skip and low-altitude bombing along with twin-engine planes loaded down with forward firing guns took it to Japanese shipping, but, haven't seen much about rocket attacks.

Seems the aerial torpedo met a rather quick demise later in the war and when you consider that the Skyraider torpedo attack on Korean dams required scrounging up people who remembered how to hang a torpedo, a big change in weapons occurred (even taking in the account of the loss of an enemy possessing large warships).

So, would you, as a late-44 pilot, in a B-25, Avenger, Helldiver, or even a fighter feel dangerous launching an attack on a cruiser (to stay in the middle) armed with guns/cannons and rockets?

 

[Greyman]

I'm not up on naval shells but figures for the 3-inch RP head:

Shell H.E. 60 lb. S.A.P. No.1 Mk.I and No.2 Mk.I
total weight: 60 lb
filling: 12.0 lb TNT or Amatol 60/40
maximum speed (at 400 yards): 1078 ft/sec
speed at 1,000 yards: 1,020 ft/sec

Rocket speeds assuming aircraft speed of 240 mph (352 ft/sec)

 

[Shortround6]

I've read where rockets were considered equal to 5" guns and a destroyer/light cruiser broadside. True?

Destroyer broadside? close. Light cruiser broadside? false unless it is a really old light cruiser.
It made for moral lifting sound bites in newsreel footage though.

Most destroyer guns fired shells from about 45to 55lbs. Most destroyers had 4-6 guns but some had 8. Trouble is a destroyer could fire a broadside every 5 seconds or faster so in one minute it could equal a squadron of aircraft with rockets. Destroyer guns did carry a lower percentage of HE to shell weight though.

Light Cruisers, with a few exceptions carried 6 in guns with 88lb to 112lb shells (the big American light cruisers used 130lb shells) and it was a small cruiser indeed that didn't carry at least 6 guns, Leaving out the big American pre war light cruisers the common number was 8 guns to twelve guns. Rate of fire could be 6 or more broadsides per minute. I could be a little off on that.

So, would you, as a late-44 pilot, in a B-25, Avenger, Helldiver, or even a fighter feel dangerous launching an attack on a cruiser (to stay in the middle) armed with guns/cannons and rockets?

Well, I would be pretty confident that the guns could kill/wound crew on deck and the rockets could mess up the top sides, sinking a post 1930 cruiser with rockets would take some doing. Post 1930 cruisers were pretty tough ships (armor and lots of water tight compartments) compared to Destroyers and merchant ships.

 

[pinehilljoe]

In an article on the B-25 in Wings/Airpower I remember one pilot saying he had better accuracy with the 75mm gun in the B-25 than with rockets.

 

[wuzak]

The thread title doesn't seem to match the OP, which seems to be more Rocket vs Torpedo.

HVAR was, of course, a rocket.
High Velocity Aircraft Rocket - Wikipedia

 

[Washing Machine Charlie]

In an article on the B-25 in Wings/Airpower I remember one pilot saying he had better accuracy with the 75mm gun in the B-25 than with rockets.

Interesting, I remember reading an article where a pilot states that rockets were better off in the hands of advanced aerial marksman.
He stated that their were two types of pilots that could hit what they aimed at, those that walked their guns onto a target and those that took a more marksmen approach and fired when the crosshairs were on target. Of the two, he considered rockets to be a waste with the former because so many were wasted walking onto target, as opposed to an aerial marksmen taking aim and firing only when ready.

 

[Washing Machine Charlie]

The thread title doesn't seem to match the OP, which seems to be more Rocket vs Torpedo.

HVAR was, of course, a rocket.
High Velocity Aircraft Rocket - Wikipedia

I agree, a little scatter brained.

It just seems when reading about the Pacific battles, after Midway, more is said about the different types of bombing techniques, rockets, and even the limited use of 75mm cannons than torpedoes, despite their use against prominent targets like the super battleships.

I love the Avenger, but, I haven't read any accounts of pilots taking it low and dropping a torpedo against the Yamamoto, which would truly be an interesting read, but, there are several minutes of film and several articles on B-25 attack runs utilizing the 75mm.

The absence of aerial torpedo "highlights" is what provoked my thinking on the matter.

 

[Shortround6]

Interesting, I remember reading an article where a pilot states that rockets were better off in the hands of advanced aerial marksman.
He stated that their were two types of pilots that could hit what they aimed at, those that walked their guns onto a target and those that took a more marksmen approach and fired when the crosshairs were on target. Of the two, he considered rockets to be a waste with the former because so many were wasted walking onto target, as opposed to an aerial marksmen taking aim and firing only when ready.

Something seems a bit off in that statement. It was hard enough trying "walk" machine gun and cannon ammo onto a target. It was tried alot and at times it worked. However at the longer ranges (say 500yds and up) the time of flight to the target could be a 1/2 second or more (longer ranges really get long flight times) so your bullet impact told you where you should have been aiming 1/2 second ago, add in the reaction time and where should you be aiming NOW to get a hit? a 300mph plane is has covered about 100 meters in 3/4s of a second.
A lot of pilots simply aimed low or short of a ground target as as they pulled up slightly the bullet impacts "walked" onto the target which is not quite the same thing.

Rockets had much longer times of flight over the same ranges. Rockets, for the most part were fired in either a fast ripple or in pairs. They didn't fire all at once (simultaneously) in order to keep them from hitting each other leaving the launchers. The ripple could be very quick. Rockets fired in pairs tell you nothing as the firing solution has changed so much before the next pair is fired and often, even firing in pairs, an attacker had several pairs in the air at one time (3rd or fourth pair is being fired as 1st pair hits?)
Pilots may well have "walked" pairs of rockets onto the target but I believe it was more a case of firing in a predetermined "pattern" (even if only in the pilot's mind) than trying to correct succeeding pairs of rockets based on the flight of the 1st/2nd pairs.

The writer of the article is correct. better results are going to come from firing all the rockets as close together as possible with a good aiming point/firing solution rather than spreading the firings out in pairs fired at different times and distances.

Look at the speeds given by Greyman in post #2. The rockets are only traveling about 3 times faster than a Hawker Hurricane. If the first pair leaves the rails at 1000yds the Hurricane will have shortened to the distance to under 700yds by the time the rockets reach the target. Aiming point for rocket/s fired at 700yds is considerably different than aiming point at 1000yds.

 

[Shortround6]

It just seems when reading about the Pacific battles, after Midway, more is said about the different types of bombing techniques, rockets, and even the limited use of 75mm cannons than torpedoes, despite their use against prominent targets like the super battleships.

I love the Avenger, but, I haven't read any accounts of pilots taking it low and dropping a torpedo against the Yamamoto, which would truly be an interesting read, but, there are several minutes of film and several articles on B-25 attack runs utilizing the 75mm.

The absence of aerial torpedo "highlights" is what provoked my thinking on the matter.

The Yamato was hit by at least 11 torpedoes, something had to drop them

There was a long period of time between Midway and the Battles for the Philippines (Musashi was hit by 19 torpedoes?) , where the US MK 13 Torpedo didn't work very well, which forced a reliance on bombs. The 75mm on the B-25s was pretty much useless against large warships. It used the same ammo as the Sherman tank. For aircraft use they used pretty much HE ammo only. Any armour much over an inch thick would stop the shell. The 75mm worked great against coastal barges/shipping, small escorts, landing craft. etc.

By 1944 the MK 13 torpedo was not only working well, it had a much different drop "envelope" than it did in 1942, when it had to be dropped low and slow. In 1944 if could be dropped from hundreds of feet in air (or 1000ft at Truk in Feb 1944)) and at speed much higher than what it could be dropped in 1942, so you aren't going to see any Avengers going in low, slow and steady in any films of the late war period. By the end of the war the outer margins of the drop envelope were 2400ft and 410kts.

You tube is not really your friend when it comes to getting "facts" on weapons.

 

[Barrett]

Sorta related: in writing the TBF/TBM book I found (I believe) a VT-16 document stating that HVAR attacks probably were not worth the effort against hard targets like bunkers, etc. Optimum delivery for 3.5 inchers (again IIRC) was a shallow dive angle at close range to improve accuracy. That profile of course put the Avenger in the heart of the AA zone. Presumably 5-inchers were mo' bettah but it's been so long that I don't recall the relative values.