When you think of unconventional aircraft, flying wings have had plenty of time in the sun over the last few decades. With striking designs like the B-2 Spirit and F-117A Nighthawk on the flight line, it’s no surprise. The lifting body never really caught on, however, and it languishes in ignominy to this day. Despite their obscurity, [rctestflight] decided to 3D print a few lifting bodies for himself and take them out for a field test (YouTube video, embedded below).
Most aircraft have a body designed with low drag, and wings designed to provide lift. Lifting body aircraft focus the body design on providing that lift and often have no real wing to the design, needing only control surfaces to compliment the body. For this project, several different designs were constructed, with the craft being drop-launched from a multirotor at significant altitude. Initial tests were hamstrung by stability problems, both due to center of gravity issues and uncertain aerodynamic phenomena. The early designs were particularly prone to suddenly entering an unrecoverable flat spin. Later modifications included the addition of further stabilizers, which helped performance somewhat.
3D printing is a great way to experiment with aerodynamic phenomena, as it’s easy to create all manner of complicated geometries to tinker with. [rctestflight] has done solid work developing a basic craft, and we’d love to see the work continue with powered tests and more development. If flying wings are more your jam, though, you can 3D print those too. Video after the break.
I beg your pardon Lewin?
Look up the X-24 family. Also the X-37 and the Space Shuttle who made use of the work on the X-24 family members. Our government also designed scads of other designs as well. Take a look at a great book on the subject of Wingless Flfight. Oh and take a look again at an earlier hack that of using a ‘copter to bring up a glider to a respectable altitude and releasing it, and hoping it would find its way back. The same idea was behind the work for those X-24 members. But with a pilot onboard. The lifting bird was a specially configured B-52.
What the Shuttle got out of the lifting body program was its landing trajectory. Nothing more. Those test vehicles proved that it was possible to safely transition to a horizontal landing from a steep and fast fall with style – without needing any sort of engine to give the craft a nudge.
Aerodynamically, the Shuttle took nothing from the lifting body tests. They were bricks with wings and a nose cone.
The new Dream Chaser is the descendant of the old program. https://www.youtube.com/watch?v=hIFgTPoG_LQ It also bears some resemblance to the Soviet MiG 105 https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-105
> What the Shuttle got out of the lifting body program was its landing trajectory. Nothing more.
Not according to “Wingless Flight: The Lifting Body Story” (https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19980169231_1998082126.pdf)
“The X-24B shared very similar speed and performance characteristics with the projected Shuttle spacecraft design, so the X-24B was used to collect operational data used in the design and development of the Space Shuttle vehicles. Scobee said that his experience flying the X-24B inspired him to apply to the NASA Astronaut Corps to fly the Shuttle spacecraft.” (page xxv)
“The M2-F1 program proved to be the key unlocking the door to further liftingbody programs, including the current Shuttle spacecraft and several other vehicles currently in-progress, such as the X-33. Flight tests of the M2-F1 supplied the boost in technical and political confidence needed to develop low lift-to-drag-ratio, unpowered, horizontal-landing spacecraft.” (page 62)
The lessons learned from the X-24A/B helped shape the overall design of the Space Shuttle.
And from the homebuilt aircraft world, the Wainfan Facetmobile!
Yep, the Space Shuttle (arguably), and a few experimental aircraft. Quite obscure compared to the huge numbers of flying wing and conventional designs out there.
Yes quite right. If anything B-2 and F-117 are example of blended wing bodies rather than lifting bodies.
It may have been accidental, but I’m sure that Zivi Nedivi is pleased as punch that his F-15’s fuselage had enough aspects of a lifting body to safely land a few years ago…
https://theaviationist.com/2014/09/15/f-15-lands-with-one-wing/
I think the fins on the bottom might be adding more weight and actually outweigh the benefits of having them there in the first place, excuse the pun.
Question. On the lifting body, are you doing a surface print or a solid print?
“Flightcom, I can’t hold it! She’s breaking up, she’s breaking–“
BRILLIANT !!! :)
That wasn’t an unrecoverable flat spin though, rather a loss of pitch control.
“Pitch is out! I can’t hold altitude!”
Yea, Steve Austin would be so triggered by this video.
This is probably a dumb idea. If the shape of the body is what generates the lift, could soft robotics be employed to make small changes to the shape of the body to aid in controlling the craft?
What would be the effect of dynamically changing the center of mass in flight?
You mean like wing warping? Here’s a link, is this what you meant?
https://en.wikipedia.org/wiki/Wing_warping
That doesn’t quite seem like what I had in mind but still something that might be an interesting application.
I have no idea if it would have any advantages over conventional control surfaces though.
In the context of a lifting body, I don’t understand the mechanism for generating lift as the body looks like an upside down wing which seems wrong. But assuming the bulge on the bottom of the craft is part of how it generates lift I would guess changing that shape affects the craft. I was thinking of a set of inflatable chambers that could be used to tune the shape of the craft.
Thing about this, I started to wonder if there might be a better way using ridged structures like channels and slots int he body that could be opened or closed (a bit like a slotted wing).
If you want to learn more, the NASA documentary Flight without Wings gives a short intro into why lifting bodies are designed the way they are: https://www.youtube.com/watch?v=ez2clDxiDv8