Douglas Designations

[aim9xray]

Can this be correct: D.411 for D.C.5?

No.

 

[Maveric]

Do you know the Number for the D.C.5?

 

[hesham]

Do you know the Number for the D.C.5?

D-510.

 

[Antonio]

American secret projects Vol 2. US Airlifters 1941 to 1961. Cox and Kaston. Crécy.
Pg 32
Model 450 C-54A
Pg 37
While developing the DC-4, Douglas also explored a series of further medium-size transport proposals to Type Specification 366 dated August 1940.

Model 366 resembled a reduced-scale DC-4 (The original design I guess) tentatively dubbed DC-6 for the commercial market. They all shared double bubble cockpit and similar wing/empennage configuration

Model 400
Model 410 December 1941
Model 425 December 1941
Model 458 November 1943

This is interesting because in between that models came the Model 423 Intercontinental bomber and XB-42 (Model 459) / XB-43 (Model 466) , sharing their design features.
Source for XB-42/43 model numbers: American Secret Projects 4 Bombers/Attack/Antisubmarine 1945-74 by Tony Buttler. Ed Crecy Pg 360/361

Pg 48

Model 415 C-74 Globemaster 19 January 1942 Revised as 415A in Feb 1942 and again in 1945
Bug eye was also proposed to be tested in the XB-19 (September 1942) replacing the existing nose section with a new one.