X-23 PRIME at NMUSAF

[ZLEA]

I was recently at the National Museum of the United States Air Force, and found that there seemed to be two different X-23 PRIMEs (Model SV-5D) on display. Of the four aircraft built, the first two were lost during testing, which means the displayed aircraft are the third and unflown fourth aircraft, a fact confirmed by this article. The attached photo, shows the two aircraft on display. The one in the background has re-entry burns, so I assume that it is the third aircraft. The aircraft in the foreground has a large structure on its tail, which the background aircraft lacks. Does anyone know what this structure is and why the background aircraft lacks it?

 

[Dew]

The structure you are referring to is to simulate the upper flaps in a fixed position. It appears an operational SV-5D was intended to use this fixed arrangement (as per Hallion's Hypersonic Revolution) but a larger/manned SV-5 would have (and did in SV-5P / X-24 guise) employed actuated upper flaps.

Confusingly a picture of what is presumably the same article is shown in @blackstar's Spacereview article you have linked above.

It is annotated as "X-23 PRIME test vehicle being prepared for launch" but as it already shows the scorching of previous use it presumably is FV-3 during, or shortly after, it's systems acceptance test for re-use Apr 28th? (FV1 & 2 being fish food by then).

However, the picture shows the same more deflected simulated flap position as the displayed un-flown article. Maybe those panels are now just missing from the FV-3 article now on display? The panels certainly look removable but the interface with the fins looks a bit more integral. edit: nope

 

[alpha_k]

where is bgrv?missing?