A U.S. Navy fighter version of Lockheed's Sirius?


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Jun 25, 2009
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While searching the web for something completely different, I came across a picture that immediately caught my attention in a full-page advertisement from Popular Aviation dated November 1937: a strange scale-model fighter variant of Lockheed's Model 8 Sirius was being advertised.

I don't usually give much credit to scale model ads as valuable data sources, but the type appeared in a page full of perfectly real and correctly-identified Navy and Army types, most of them showing the real aircraft. But a fighter version of the Model 8?? The Sirius was a single engine, propeller-driven monoplane designed and built by Jack Northrop and Gerard Vultee while they were engineers at Lockheed in 1929, at the request of Charles Lindbergh. A later version, the Model 8D Altair, was a basically a Sirius with a retractable undercarriage, one of the first aircraft designs with that feature.

The U.S. Navy did indeed use a single Lockheed Model 8 derivative, but it was not a Sirius, it was an Altair built by the Detroit Aircraft Corporation. Indeed, besides one prototype, four converted Siriuses and two newly-built examples, two more Altair aircraft had been built by Detroit, a subsidiary of Lockheed, as their Model DL-2A. One of these two aircraft was acquired by the U.S. Navy and used as staff transport aircraft. It was designated XRO-1, indicating the Navy's first Lockheed (O) transport (R) type in experimental form (X).

What is weird about this image is that it is clearly represents a Sirius in model form, not the later Altair, since it has fixed undercarriage and single cockpit. The image also carries a different color scheme from the one sported by the XRO-1 (see attachment), one which would be more compatible with a fighter or a racer, indeed, than a transport. The text is equally puzzling (here is an extract):

42" Span, Length 20½, Weight 3½ oz. ¾" scale

New 4-gun Navy fighter. Model will rise from land or water in few feet.
This is a sensational model and only one of its type in the world.
Above model is latest improved type, just out.

The designation "P23A" is most probably bogus since it is neither standard Navy (first Navy fighter by Lockheed ought to have been designation XFO-1, and we know this was allocated much later to the Rising Star, better known as the "Vertical Riser" or "Salmon") nor standard Lockheed (as we said earlier, it was a Model 8 variant). It wasn't even a confusion with a U.S. Army type, since the P-23 was the last development in the line of Curtiss Hawk biplane fighters.

Has anyone heard of the U.S. Navy ever evaluating a Sirius, or considering procuring it at some point? I certainly can see it be used as a racer, but as a fighter? At any rate, I find the idea fascinating and full of possibilities... If anyone knows about such a project, I'd be glad to hear about it!!


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ACCESS: Top Secret
Senior Member
Jul 25, 2007
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Interesting. But, as you suggest, a Sirius-derived single-seat naval fighter is improbably - especially as a newly-introduced aircraft in 1937!

A year earlier, Miniature Aircraft Corp. of New Brighton, NY had also kitted a 'P-24B Army Fighter' with an obvious 1:1 scale Lockheed-Detroit connection. I mention that kit because, although meant to depict a full-sized Sirius derivative, the model has the same 32" wingspan as your more mysterious ''P23A Navy Fighter'.

My guess is that Miniature simply invented the 'P23A' to try to extend the run of an under-performing kit (albeit in modified, single-seater form). Why Miniature bothered with a 32" scale YP-24 as late as 1936 is another puzzle -- especially when they'd done a 28" span Sirius as far back in 1930!

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