I hadn't positively identified it, just came across the same model in a picture of a number of models from Lockheed. I don't recall the book I saw it in unfortunately, but I seem to remember I found the book whilst looking for X-24c information.Could this study and model talked about in the PDF be related to LRAPIS or Long Range Advanced Piloted Interceptor System?"Advanced Interceptor"but quite possibly not Vought(edit: it's Lockheed) - not sure where else to put them:
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