This is a 'what-if' scenario;
What would be the best arrangement for an air cooled single engine heavy cannon armed tank buster (and CAS) aircraft for WW2 ???.
I feel a single heavy cannon centerline mounted is better than 2 cannon wing mounted. In the Hurrican IID and the Il-2, the wing cannon don't fire at the exact same time, their recoil introduces yaw which throws off the point of aim, something not present in a centerline mounting. Plus a single cannon mounting allows a larger more effective weapon for the same weight compared to two wing cannon.
Most agree that an air cooled engine is a must for combat survivablity. Since there never was a high power (i.e. 1500 HP plus) inline air cooled engine, one has to chose a radial engine. Using a radial however eliminates the option of an engine mounted heavy canon ala the Yak-9T.
In my mind, that leaves three potential arrangements;
1. Engine mounted over the wing, tractor propeller, cannon in the nose firing thru the propeller hub, and cockpit between the weapon bay and the engine. The Itallian Piaggio P.119 (prototype only) used this arrangement. The Amerian P-39/P-63 also used this arrangement, but in place of the Allison liquid cooled engine, the proposed tank-buster would have a air cooled radial engine.
Disadvantage: With the weapon in the extreme nose, as the heavy cannon ammo is expended, the airplane becomes tail heavy, increasing the risk of a spin.
2. Similar to the above but with the cockpit immediately behind the propeller, and the weapon bay between the cockpit and the engine. Besides the drive shaft to the propeller, the cannon barrel would run under the cockpit to fire through the propeller hub as in the previous proposal. The aircraft profile would be somewhat similar to the 'paper only' Me 509.
Advantage; Good pilot visibility. With the cannon closer to the center of gravity, thed is less trim change as the cannon ammo is expended. Disadvantage: Having the pilot straddle both the drive shaft and the cannon barrel results in a deep, potentially poorly aerodynamic fuselage.
3. A pusher arrangement, with the pilot in the nose, cannon bay between the cockpit and wing, and engine again near the wing/center of gravity. Imagine air cooled versions of the (paper only) Bv P.193.01 or a scaled down Douglas XB-42. Advantage; Good pilot visiblity. As above, having the cannon near the center of gravity limits trim change as the ammo is fired off. Disadvantage: On quickly built forward airstrips, rocks thrown up from the landing gear can damage the propeller. Same bail-out hazards as all pusher designs.
My opinion is that the Bv P.193.01 or 'mini-XB42' pusher is the best option. Depending on the producing nation it would be built around an 18 cylinder version of the BMW 801 with a belt fed BK 3.7 cannon OR a Wright R-3350 and 37 mm M9 cannon OR Bristol Centaurus / 40 mm Vickers type S gun.
Rebuttal?? Comments???
What would be the best arrangement for an air cooled single engine heavy cannon armed tank buster (and CAS) aircraft for WW2 ???.
I feel a single heavy cannon centerline mounted is better than 2 cannon wing mounted. In the Hurrican IID and the Il-2, the wing cannon don't fire at the exact same time, their recoil introduces yaw which throws off the point of aim, something not present in a centerline mounting. Plus a single cannon mounting allows a larger more effective weapon for the same weight compared to two wing cannon.
Most agree that an air cooled engine is a must for combat survivablity. Since there never was a high power (i.e. 1500 HP plus) inline air cooled engine, one has to chose a radial engine. Using a radial however eliminates the option of an engine mounted heavy canon ala the Yak-9T.
In my mind, that leaves three potential arrangements;
1. Engine mounted over the wing, tractor propeller, cannon in the nose firing thru the propeller hub, and cockpit between the weapon bay and the engine. The Itallian Piaggio P.119 (prototype only) used this arrangement. The Amerian P-39/P-63 also used this arrangement, but in place of the Allison liquid cooled engine, the proposed tank-buster would have a air cooled radial engine.
Disadvantage: With the weapon in the extreme nose, as the heavy cannon ammo is expended, the airplane becomes tail heavy, increasing the risk of a spin.
2. Similar to the above but with the cockpit immediately behind the propeller, and the weapon bay between the cockpit and the engine. Besides the drive shaft to the propeller, the cannon barrel would run under the cockpit to fire through the propeller hub as in the previous proposal. The aircraft profile would be somewhat similar to the 'paper only' Me 509.
Advantage; Good pilot visibility. With the cannon closer to the center of gravity, thed is less trim change as the cannon ammo is expended. Disadvantage: Having the pilot straddle both the drive shaft and the cannon barrel results in a deep, potentially poorly aerodynamic fuselage.
3. A pusher arrangement, with the pilot in the nose, cannon bay between the cockpit and wing, and engine again near the wing/center of gravity. Imagine air cooled versions of the (paper only) Bv P.193.01 or a scaled down Douglas XB-42. Advantage; Good pilot visiblity. As above, having the cannon near the center of gravity limits trim change as the ammo is fired off. Disadvantage: On quickly built forward airstrips, rocks thrown up from the landing gear can damage the propeller. Same bail-out hazards as all pusher designs.
My opinion is that the Bv P.193.01 or 'mini-XB42' pusher is the best option. Depending on the producing nation it would be built around an 18 cylinder version of the BMW 801 with a belt fed BK 3.7 cannon OR a Wright R-3350 and 37 mm M9 cannon OR Bristol Centaurus / 40 mm Vickers type S gun.
Rebuttal?? Comments???
