Shortround6
Major General
The Gloster shows up in a number of "what if's" but it needed development, mainly in a new engine or else it gets rather distorted.
The two planes are remarkably similar in size, even the wing area is only off by about 5% on 230-241sq ft wings.
Loaded weight is within a few hundred pounds (if the Zero is not carrying a drop tank).
Weight of armament is close. One 20mm is only a little lighter that 3 Brownings.
Two main problems are we have to believe the published speed for the F.5/34 which certainly seems high but that has been gone over in other threads.
The other problem, and using a lot of hindsight, The F.5/34 has nowhere to go engine wise.
The Prototype used a Mercury IX engine that was rated at 725hp for take-off and 840hp at 14,000ft which helped with the speed, it also explains the 11 minutes to 20,000ft even using a two pitch prop (ok two pitch props don't work well in climb). Plan was to change to the Perseus engine and there were two choices. The Perseus X (fully supercharged ) with a take off rating of 750hp and 880hp at 15,500ft. A useful increase over the Mercury but not exactly earth shaking (or sky ripping).
However the Zero (unknown in the west at this time) was flying with a Mitsubishi Zuisei engine of 780hp for take-off and 875hp at 11,800ft. The Japanese were not happy. After two prototypes they switched to the Sakae 12 engine that gave 940hp for take-off and 950hp at 13,780ft
The F.5/34 had several choices (in "what if" land), switch to the Perseus XI/XII medium supercharged engine and get 830hp for take-off (used in the Blackburn Skua and Roc and many Bothas) and 905 hp at altitude but altitude was only 6500ft. Might be OK (maybe for a British Naval fighter of 1938-40 but it does really give up the higher (over 10,000ft) altitudes. Perseus weighs 465kg. The Sakae 12 was about 530kg.
with hindsight we know the Perseus really didn't go any further. They had the Taurus and in 1938/39 they didn't know how bad that was going to get.
It also weighed 590kg and even running on 100/130 fuel it maxed out at 1130hp at 3500f. Now take off about 2% for every additional 1000ft of altitude.
Things are not looking good in the middle teens.
Last gasp, Hail Mary pass. Stuff the Hercules engine in. Except..................................
Weight 835kg, Power in early form was 1325hp T-O and 1375hp at an ear popping, nose bleeding 4000ft. Fixed in the two speed Hercules III version.
Now go back and look at the original Mercury engine used in the F.5/34 prototype. 454kg. sticking in a Hercules adds 380kg and you still need a bigger prop (and more fuel). Increasing the powerplant weight by about 83% is going to distort the whole plane. You might get there but there is a lot of stuff that has to be changed.
The Kinsei engine used in the last two A6M8 prototypes might have gone to around 675-680kg?
A bit long winded but there doesn't seem to be any practical way to get the F5/34 into the performance envelope of the A6M2 with the existing engines or with anything in the logical pipeline. The Mercury, Perseus and Taurus were all 24.9-25.4 liter engines and the Sakae engine was a 27.9 liter engine.
The P&W R-1830 was a 30 liter engine.
even if they had ordered the F.5/34 into production instead of the Roc and planned to swipe Taurus engines from the Beaufort (by sword point?) the problems with the Taurus engines would have soon stopped that.
The two planes are remarkably similar in size, even the wing area is only off by about 5% on 230-241sq ft wings.
Loaded weight is within a few hundred pounds (if the Zero is not carrying a drop tank).
Weight of armament is close. One 20mm is only a little lighter that 3 Brownings.
Two main problems are we have to believe the published speed for the F.5/34 which certainly seems high but that has been gone over in other threads.
The other problem, and using a lot of hindsight, The F.5/34 has nowhere to go engine wise.
The Prototype used a Mercury IX engine that was rated at 725hp for take-off and 840hp at 14,000ft which helped with the speed, it also explains the 11 minutes to 20,000ft even using a two pitch prop (ok two pitch props don't work well in climb). Plan was to change to the Perseus engine and there were two choices. The Perseus X (fully supercharged ) with a take off rating of 750hp and 880hp at 15,500ft. A useful increase over the Mercury but not exactly earth shaking (or sky ripping).
However the Zero (unknown in the west at this time) was flying with a Mitsubishi Zuisei engine of 780hp for take-off and 875hp at 11,800ft. The Japanese were not happy. After two prototypes they switched to the Sakae 12 engine that gave 940hp for take-off and 950hp at 13,780ft
The F.5/34 had several choices (in "what if" land), switch to the Perseus XI/XII medium supercharged engine and get 830hp for take-off (used in the Blackburn Skua and Roc and many Bothas) and 905 hp at altitude but altitude was only 6500ft. Might be OK (maybe for a British Naval fighter of 1938-40 but it does really give up the higher (over 10,000ft) altitudes. Perseus weighs 465kg. The Sakae 12 was about 530kg.
with hindsight we know the Perseus really didn't go any further. They had the Taurus and in 1938/39 they didn't know how bad that was going to get.
It also weighed 590kg and even running on 100/130 fuel it maxed out at 1130hp at 3500f. Now take off about 2% for every additional 1000ft of altitude.
Things are not looking good in the middle teens.
Last gasp, Hail Mary pass. Stuff the Hercules engine in. Except..................................
Weight 835kg, Power in early form was 1325hp T-O and 1375hp at an ear popping, nose bleeding 4000ft. Fixed in the two speed Hercules III version.
Now go back and look at the original Mercury engine used in the F.5/34 prototype. 454kg. sticking in a Hercules adds 380kg and you still need a bigger prop (and more fuel). Increasing the powerplant weight by about 83% is going to distort the whole plane. You might get there but there is a lot of stuff that has to be changed.
The Kinsei engine used in the last two A6M8 prototypes might have gone to around 675-680kg?
A bit long winded but there doesn't seem to be any practical way to get the F5/34 into the performance envelope of the A6M2 with the existing engines or with anything in the logical pipeline. The Mercury, Perseus and Taurus were all 24.9-25.4 liter engines and the Sakae engine was a 27.9 liter engine.
The P&W R-1830 was a 30 liter engine.
even if they had ordered the F.5/34 into production instead of the Roc and planned to swipe Taurus engines from the Beaufort (by sword point?) the problems with the Taurus engines would have soon stopped that.
