First of all, it's not a "thingy". It is positively a Pabst ramjet as
evidenced by its connection to one of the Fw Triebflugel's wings seen
in the photo. And it is being windtunnel tested.

That, except for the Triebflg. wing (more likely a simple streamlined
strut)was what I was suggesting. The guy was being a dunderhead. Of
course it wasn't moving, it was a test article in a wind tunnel! Jeez.

I didn't think the "V-4" ramjet looked
all that much like a Pabst ramjet though.

Really? OK, here's a comparison of all the late-war ramjets available
to the Germans:

The Pabst engines were usually proportionally shorter, but all in all,
that isn't all that important.

Still think it might have been
a Rheinbote like missile with a ramjet sustainer, which could have been
done with a minimum of effort.

On the Unicraft page the first depiction shows the V-4 missile with a
RATO unit slung underneath for catapult launch. Rhinebote was powered
by a rocket engine and launched off a SSM erector. The V-4 was
launched like the V-1:

You're not thinking like an engineer. The Rheinbote was a dirt simple
rocket stack, a tube with fuel and fins. To rethink the function with a
ramjet instead of solids is almost a no-brainer. That makes the
development of the "V-4" more credible, even if it wasn't done by the
Rheinbote team, anyone with some ramjet R&D and even a hint of a notion
of V-1 or Rheinbote ops could easily put it together.

The two other depictions of the V-4 on the Unicraft page suggest
postwar research done by the Russians at N-II-88. The V-4 on top of
the V-2 looks remarkably similar to the Russian EKR concept, but in
that case the V-4 was replaced with a Sanger-looking missile.


I suspect the "V-4" on top of an A-4 was little more than wishful
thinking at the time.

For that matter, the "V-4" was likely little more than a vaporware
threat rather than a credible piece of hardware.