Douglas TBD range needed

[JoeB]

Originally Posted by Markus Becker

I´m gathering info on various US carrier a/c. From 'The First Team' I found out an SBD had a combat radius of 170 to 220nm depending on the bombload and that it could make a 300nm search, presumably with a 500lb bomb?

The Wildcat´s combat radius is at least 125nm but up to 200nm was mentioned once.

The TBD has totally eluded and confused me. At Coral Sea torpedo armed TBD were send against a target -Shoho- that was reported 200nm away. Cruise speed for a TDB with a fish is 100 to 110 knots. The strike departed at 9:45, the attack began at 11:05. That 80 minutes. TBD could cover 140nm in that time, not 200. Ok, the inital report was wrong, a second place the Shoho 30nm away from the first but that would still be at least 170nm.

The USN quoted aircraft ranges in statute mile, not nautical miles. It seems strange, since speeds for a/c, like ships, were quoted in knots, but it's clear in original documents, and a cause of confusion in books. Just glancing back at Lundstrom, he quotes a/c ranges as simply 'miles', and in some cases he quotes official figures, so I'd assume he means statute miles.

As on previous thread, the range of SBD can be benchmarked for SBD-5 (with no external tanks and otherwise pretty similar to the 1942 model SBD-3) from "Aircraft Characteristics and Performance" sheets dated June 1 1944: range with 1000# bomb=1115 statute miles, radius 240, same nominal range but 260 mile radius with 500# bomb. The assumptions are given in detail. Any quote of a practical range that differs can be compared to this.

Again for types not still in service ca. 1943 there don't seem to be official USN statistics for combat radius. The numbers on Wiki for TBD are also quoted in Barrett Tillman's "TBD Devastator Units of the US Navy", 435 mi with Mk13 torpedo, 715 miles with 2*500# bomb. He describes these as 'tactical ranges' so might be different from the still air max range in the 1944 document for SBD; might include some reserves or margins, I don't know. Also as mentioned last time, it wouldn't necessarily work to use the same % of range as radius for a 1115 range SBD as 716 (assuming it's comparable) TBD, because certain reserves are a constant, so reduce the % for the shorter legged a/c under the same assumptions. OTOH if longer and shorter legged a/c operate alongside one another, there would be pressure to allow lesser margins for the shorter range planes to extend the radius of the whole air group as much as possible.

The same book gives the radius of the TBD strike v Shoho as 170 miles and again I would assume that means statute miles.

Joe