The French Edgar Brandt company had a design in 1940 for an eight inch shell, intended for naval guns, with HEAT functionality. My understanding is that it was projected to have, under optimal conditions, penetration of ~ 500mm / 20 inches.
Brandt also was interested in the use of HEAT technology in anti-armored-ship aerial bombs.
Kinetic energy AP shells and bombs require extremely strong and shock-resistant cases to achieve large penetrations, and therefore are very heavy. There is an inverse relationship between shell weight and maximum range for a given gun pressure capability. And, the amount of ordnance that an aircraft can deliver obviously is limited by weight. HEAT devices of a given diameter can be much lower mass than kinetic energy devices of comparable penetration.
The Brandt shell would have required fin stabilization and a smoothbore gun to achieve that much penetration. But, that gun possibly could have operated at much lower pressure since the projectile would be so much lighter. Lower pressure guns can have much lower mass, and are less expensive to build. And, lower topside weight is always a good thing in naval design.
Perhaps a relatively inexpensive ship the size of a destroyer could have carried a main battery of such eight inch lower pressure guns, with enough range to duel with cruisers. Or, a cruiser with higher pressure guns might have had enough range to duel with battleships, or outrange conventional cruisers.
Brandt also was interested in the use of HEAT technology in anti-armored-ship aerial bombs.
Kinetic energy AP shells and bombs require extremely strong and shock-resistant cases to achieve large penetrations, and therefore are very heavy. There is an inverse relationship between shell weight and maximum range for a given gun pressure capability. And, the amount of ordnance that an aircraft can deliver obviously is limited by weight. HEAT devices of a given diameter can be much lower mass than kinetic energy devices of comparable penetration.
The Brandt shell would have required fin stabilization and a smoothbore gun to achieve that much penetration. But, that gun possibly could have operated at much lower pressure since the projectile would be so much lighter. Lower pressure guns can have much lower mass, and are less expensive to build. And, lower topside weight is always a good thing in naval design.
Perhaps a relatively inexpensive ship the size of a destroyer could have carried a main battery of such eight inch lower pressure guns, with enough range to duel with cruisers. Or, a cruiser with higher pressure guns might have had enough range to duel with battleships, or outrange conventional cruisers.
