Vulcan Cannon

[KJ_Lesnick]

This might be a silly question but would the Vulcan cannon have been significantly in capability if it had been designed to use the 20mm x 110mm used by the Hispano-Suiza HS.404, the Colt Mk.12, and the Pontiac M.39 vs. the 20mm x 102mm rounds actually used?

[Rheged]

Being less than half awake, I totally misread this, and for a second or two had a surreal picture of an Avro Vulcan with a full broadside of 32 pounder muzzle loaders installed!

  Surreal moment over, and trying to be sensible, I don't think that there would have been any great variation in capability if the alternative round described had been used.  It may possibly have aided interoperability and ease of supply.   Others more  au fait with the weapon may have thoughts on installation  and ammunition feed issues.

[PR19_Kit]

Being less than half awake, I totally misread this, and for a second or two had a surreal picture of an Avro Vulcan with a full broadside of 32 pounder muzzle loaders installed!

Now there's inspiration for a Whiff of monumental proportions...... 

It would need a flag mast to carry the 'England expects...............' flag hoist of course. 

[rickshaw]

This might be a silly question but would the Vulcan cannon have been significantly in capability if it had been designed to use the 20mm x 110mm used by the Hispano-Suiza HS.404, the Colt Mk.12, and the Pontiac M.39 vs. the 20mm x 102mm rounds actually used?

As the general muzzle velocity of the 20x110mm round is given as being ~840–880 m/s from the HS,404 whereas the muzzle velocity from the M61 Vulcan is generally given as being ~1,050 m/s (PGU-28/B round) I think it would have detracted from the utility of the M61.   In addition, you'd have a greater moving mass as the round for the HS,404 is heavier than the round for the M61.

[KJ_Lesnick]

Rheged

Being less than half awake, I totally misread this, and for a second or two had a surreal picture of an Avro Vulcan with a full broadside of 32 pounder muzzle loaders installed!

Hey, why not -- it would definitely put a whole new spin on the term "gunship" lol


rickshaw

As the general muzzle velocity of the 20x110mm round is given as being ~840–880 m/s from the HS,404 whereas the muzzle velocity from the M61 Vulcan is generally given as being ~1,050 m/s (PGU-28/B round) I think it would have detracted from the utility of the M61.

Really?  That's interesting as up to now I was under the impression that early on at least it was a slower round: Learn something new every day.

In addition, you'd have a greater moving mass as the round for the HS,404 is heavier than the round for the M61.

Do you think it would have made a major issue with jamming?

[scooter]

Being less than half awake, I totally misread this, and for a second or two had a surreal picture of an Avro Vulcan with a full broadside of 32 pounder muzzle loaders installed!

Nah, Their Airships would probably rate it a frigate with 12 pdrs.

[rickshaw]

rickshaw

As the general muzzle velocity of the 20x110mm round is given as being ~840–880 m/s from the HS,404 whereas the muzzle velocity from the M61 Vulcan is generally given as being ~1,050 m/s (PGU-28/B round) I think it would have detracted from the utility of the M61.

Really?  That's interesting as up to now I was under the impression that early on at least it was a slower round: Learn something new every day.

In addition, you'd have a greater moving mass as the round for the HS,404 is heavier than the round for the M61.

Do you think it would have made a major issue with jamming?

Possibly.  What do you think?

[Weaver]

The 20x102mm round started out as a 60cal (15mm) round but was then necked out to 20mm, hence the short cartridge case. The 20x102mm round is lighter, at 101g than the 20x110mm at 129g, which explains the higher muzzle velocity, but then you could argue that the heavier round hangs onto it's velocity longer so it should be more accurate at longer ranges and harder-hitting when using AP rounds.

It's worth pointing out that although the USN's Mk.12 is listed as using 20x110mm ammo, it wasn't the same 20x110mm as the standard Hispano! Instead it was a stretched version of the 20x102mm, with a projectile weight of 110g and a m/v of 1,010 m/s.

Tony William's Flying Guns The Modern Era attempts to assign effectiveness 'power scores' to guns and ammo by making various calculations. The scores it gives for these three rounds are:

20x102 : 22
20x110 : 20
20x110 USN : 23

Off at a tangent: there was an experiment version of the Vulcan chambered for the 30x113mm ADEN/DEFA round: now that would have been interesting!