Delta-winged X-15, in 1/72

[dhanners]

As the X-15 racked up one milestone after another, program managers looked for ways to expand its capabilities. Some of the ideas were rather fanciful, if not impractical; for example, one concept involved mounting the X-15 atop a modified Titan rocket to launch the plane and its pilot into space.

One concept that did gain traction inside NASA was for a delta-winged X-15, using an updated rocket motor. (Others in the program believed that while there was a need for a delta-winged research plane, it should be a new design.) There were some problems that needed to be worked out, but North American Aviation actually started building the wings.

The plan was to modify X-15-3, 66672. According to a work flow chart, conversion work was to begin in April 1968. But on 15 November 1967, 66672 was destroyed when pilot Michael Adams went into a hypersonic spin and crashed, killing Adams. The plan for a delta-winged X-15 ended with the crash.

To build my X-15 delta, I used a YukonJohn repaint of Henry Yuen’s X-15 model. It is 1/72nd scale. The repaint represents 66672, and I scratchbuilt the delta wings and winglets out of black cardstock, and fashioned a rocket bell out of gray cardstock. Using a Thommy Eriksson rendering as a guide, I also added other details.

I couldn’t find whether the delta-winged X-15 would’ve had its fuselage extended (ala the X-15A-2) so mine isn’t extended. Eriksson’s rendering does, however, show extended side tunnels, so I scavenged parts from an unbuilt ‘A-2 model to extend them.

[mbauer]

I have a couple of books, will look at the chapters that mention the Delta Wing for the extension.

ROCKETSHIP X-15 Myron B Gubitz and AT THE EDGE OF SPACE Milton O Thompson one of them mentioned the Delta.

I do have a stomp rocket version of the Delta from a 3-vu from a PDF

Mike

[mbauer]

Found it: X_15_Frontier_of_Flight-Ebook

PDF file on my computer: Not Sure where I got it, think someone posted a link here at PM for it:

Paraphrase: NASA mentioned that a current X-15 could be changed by adding a super-thin hypersonic Delta Wing replacing the current wing and tail. Flight at sustained MACH 7 with brief forays at MACH 8. The X-15 fuselage structure, engine, and controls would be retained with little modification.

Page 564 of 644 to find the above comments.

Cool photo on page 328: the X-15 Delta Wing launching piggyback from a XB-70 bomber at Mach 3+.

Here is the link for the e-book: X-15: Extending the Frontiers of Flight | NASA looks like it was updated (2020) after I got my version. Well worth the read if you like the details of how something was thought of, through actual flight testing. Lots of talk about wind tunnels, math, all kinds of cool stuff.

It was this e-book that I decided to recreate all the test aircraft designed to compete for the final X-15 design. Stomp Rocket set of the designs for all the drawings/aircraft proposed: North American Aviation (NAA) won but the Republic entry had a really interesting way to land-the pilot had to look through a periscope.
Did a chart of the designs to compare size and capability:


Here are basic drawings I did to show basic look of each for a 3vu:








Mike

[dhanners]

Thanks, Mike. I’ve got the ebook on my iPad. Some great insights.

There were numerous issues that would’ve had to be surmounted to make a delta-winged X-15 reality. One was the need to relocate the nose gear aft because the plane would have a high angle-of-attack on landing.

Perhaps the biggest problem was how to launch it. It was believed it would overtax the B-52 carrier aircraft, so engineers began looking at carrying it aloft in the belly of the sole remaining B-70.

In one meeting, X-15 pilot Bob Rushworth noted that carrying the X-15 in the B-70’s belly was a bad idea because if there was an in-flight problem on the B-70, there’d be no escape for the X-15’s pilot since the rocket plane’s ejection seat fired upward.

Rushworth told the engineers — facetiously — that the X-15 would fit just as well on top of the B-70 as the bottom. The engineers took him seriously, though, and came back with designs to do just that.

In the end, though, they concluded that modifying the last B-70 to carry the X-15 would be insanely expensive.

[Mark Hansen]

Originally Posted by dhanners

...Rushworth told the engineers — facetiously — that the X-15 would fit just as well on top of the B-70 as the bottom. The engineers took him seriously, though, and came back with designs to do just that.

In the end, though, they concluded that modifying the last B-70 to carry the X-15 would be insanely expensive.

It would have probably looked somewhat like the M-21/D-21 combo. If it had been built, I can't imagine it would have been popular with the X-15 pilot or the B-70 crew.

[surfduke]

Your work is undeniably the best detailed model of this subject. WOW!

[aansorge]

What would our space program look like today if we had pursued the rocket plane approach rather than the all efforts towards Apollo approach we took? Interesting line of thought.

[murphyaa]

Originally Posted by Mark Hansen

It would have probably looked somewhat like the M-21/D-21 combo. If it had been built, I can't imagine it would have been popular with the X-15 pilot or the B-70 crew.

Now I need to make a delta winged X-15 model to mount on top of my B-70 model.

[mbauer]

Originally Posted by murphyaa

Now I need to make a delta winged X-15 model to mount on top of my B-70 model.

Have you seen the photo? Was hoping you'd catch on!

Mike

[dhanners]

There would’ve been a number of issues launching an X-15 from a B-70. For that matter, there would’ve been a number of issues putting a delta wing on an X-15.

(And speaking of B-70s, Murph, what are those dark areas atop the cockpit on the two B-70 offerings on your website? I’ve never seen them in any photos of the actual plane.)