Did you know that in the EW PTO events, a strong case can be made for using the B5N over the TBM as a substitute for the TBD? Now I would like to try and gauge the opinion of the BBS. Please read the information, and state your opinion; is the B5N a better approximation of the TBD than the TBM is?
The deck speed of the TBM is 255mph without WEP, top speed of around 270mph at ~2,500ft and 17,500ft. The maximum speed of the TBD was 202mph at 7,000ft.
To compare, the B5N2's speed is 217mph at sea level with a clean configuration (no torpedo), and 236mph at 12K.
The rear firepower of the TBD's single .30caliber machine gun is much closer to the B5N's single 7.7mm mg, than it is to the TBM's single .50 and single .30cal ventral position.
I've tested some times for deceleration from a dive for the TBM vs the A6M2. The A6M2 takes ~55 seconds to decelerate from 375mph to about 282mph, and ~1:26 to decelerate to 271mph.
The TBM, loaded with a torpedo, takes ~47 seconds to decelerate from ~375 to 280mph, 1:18 to decelerate to 269mph, 2:00 to decelerate to 255mph.
So from a dive, both aircraft take roughly comparable times to decelerate to the 280mph mark. However, the TBM has a higher dive speed in excess of 500mp, where as the A6M break its wings when pulling up much above 400mph.
Let us assume for the sake of argument that a group of A6M2's exit their dive 3k behind a group of TBM's that have also exited a dive. For ~40 seconds, we know their speed differential is essentially nil, assuming both have the same dive speed (which is improbable, and likely to favor the TBM in a real encounter). The A6M will take an additional 31 seconds to decelerate to Vmax of 271mph at 500ft. The TBM will take an additional 53 seconds to decelerate to it's Vmax.
For the ease of calculations and expediency, lets simply assume the TBM has decelerated to 255mph by 1:26. This gives us an average speed of 275mph for the A6M2 from 0:55 to 1:26, and an average speed of 267 for the TBM, giving us an average speed differential of 8mph for time ~0:50 to 1:26. So by time 1:26, we can assume the A6M2 has closed the gap from 3000yds to 2860yds.
At 1:26, we assume the TBM is at a constant speed of 255mph and the A6M2 is at a constant speed of 271mph. This gives us a speed differential of 16mph, or 7.82 yds/second. We simply divide the remaining distance of 2860 by 7.82yds/s to give us the time, in seconds, it will take for the A6M2 to close the gap. The answer is 365s, or 6.08 minutes.
Were the initial distance 2000yds, the A6M2 would take 3.95 minutes to close the gap. Were it 1500yds, it would take 2.9 minutes.
To put that in perspective, the A6M2 had, at absolute minimum, 69mph over the TBD, assuming the deck speed is the same as its maximum speed. Realistically, this is likely to be in excess of 85mph.
The case for using the B5N can be summarized as significantly better approximation of the TBD's speed and rear firepower.
The case for the TBM is essentially that it has 2 .50's to represent the single .30 cal, or single .50caliber in late model TBD's, and that it is blue (although the wrong shade of blue, being a late 1944 aircraft).
