A flyable rocket idea

The latest idea is to take the basic delta wing, attach some rocket engines to it, plus a S4B rocket stack that would take a crew to orbit.

There would be Falcon 9 engines and an S4B type rocket in the middle.  The delta wing would hold the rocket below it.  It would be attached on the underside of the delta wing.  There would be landing gear and it would take off like a plane.

Running it through the rocket equation with a few assumptions and it checks out.  You wouldn't need much fuel, since the delta wing is only going to go up to about 100k feet and less than mach 3 and release the S4B.  The S4B can reach orbit from there with a payload about the weight of the Gemini.

Assumptions would be 60k lbs for the delta wing airframe-- about the same as an empty X-33.  Add 40% to the mass for the Falcon 9 first stages (2) and the S4B in order to make it all reusable.

Come to think of it, you don't have to use Falcon 9 fuselages.  You just need a place to put the fuel.  For that matter, the fuel could go into fuel tanks inside the delta wing.  Thus, it would be integrated into two packages--- the airframe that ferries the rocket up to 100k feet.

There's lots of room to make the rockets more powerful and to carry more mass.  For example, you would only use about 1/4 of the available mass for fuel for the two Falcon 9's for just one rocket, much less two.   That means you can add the fuel back in and use that fuel to fly back to base.

It wouldn't be using all 18 Falcon 9 engines.  It could probably get by with as few as 6 at full power.  At take off, all six engines wouldn't be needed.  The atmosphere gives a lift as opposed to launching vertical, so full power isn't needed.  Full power with all 6 engines would only be needed when going to a vertical trajectory.  That occurs when lift from the atmosphere is insufficient to climb to 100k feet.

The way it would look like is maybe a couple engines fire and that gets the airframe up.  It goes up to 30k feet and then needs to go vertical because there's not enough lift at that point.  Now all six engines will fire up at full power and it goes vertical climbing to 100k feet.  Then the S4B is released and flies up to orbit.  In orbit, the S4B releases its payload and then returns to earth.  It too will be reusable.  The capsule will splash down and is recovered to be used again.  Thus, all major parts are reused.