Goblins to Gremlins
Way back in 1947,
McDonnell Aircraft
introduced the XF-85 Goblin:
a prototype fighter designed
to drop out of a B- 36
bomber to defend it from
enemy interceptors. Not only
was it one of the ugliest
aircraft ever built, it wasn’t
really capable of fending off
enemy jet fighters, so only
two were built before the
program was terminated.
The concept of
employing such “parasitic” fighters has been reincarnated a
few times, with pretty much the same degree of success.
However, the Defense Advanced Research Projects Agency
(DARPA) believes that is has it right this time in the form of
its Gremlins program, which seeks “to show the feasibility
of conducting safe, reliable operations involving multiple air-launched, air-recoverable unmanned systems.” In other
words, they want to launch
groups of Gremlin UASs
from bombers, transport
aircraft, fighters, and other
small fixed-wing aircraft
before they encounter
adversary defenses.
When the Gremlins
complete their mission, a C-
130 transport aircraft would
grab them out of the air and
carry them home, where
ground crews would prepare
them for redeployment
within 24 hours. Each one
could be used up to 20 times. Rather than farming
everything out to the usual huge defense contractors,
DARPA “strongly encourages participation ... by
nontraditional performers, including small businesses,
academic and research institutions, and first-time
government contractors.” So, feel free to offer proposals at
www.darpa.mil.
Artist’s concept of low cost, air-retrievable Gremlin
unmanned air systems.
by Jeff and Jenn Eckert
Robytes
Printing on Air
When we think of 3D printing, we generally
picture a mechanism in a box that produces little
plastic things. However, in the Netherlands, a
company called MX3D ( mx3d.com) is thinking
(literally) outside the box with a different kind of print
technology. According to the company, “Our robots print
sustainable materials such as metals and synthetics in
virtually any size or shape. Our engineers, craftsmen, and
software experts bring together digital technology,
robotics, and traditional industrial production.”
The MX3D Metal unit is a multi-axis industrial robot
combined with a welding machine and software (provided
by Autodesk) that drives the combination. It can print with
a variety of metals, including steel, stainless steel,
aluminum, bronze, and copper. The MX3D Metal doesn’t
even need external support structures, as it adds small
layers of molten metal to print things in mid air.
Proof of concept is apparent in a footbridge that will
span a canal in downtown Amsterdam. The company
declined to offer specifics about cost, but did note that it is
cheaper than the more traditional selective laser melting
process. “In the future,” it was predicted, “you might even
see torch-carrying robot arms building bridges for cars or
trains. The bots could also be useful at sea to fix offshore
oil rigs, or in space to repair broken satellites.” For vids, just
search MX3D on You Tube.
SERVO 03.2016 7
Robotic 3D printers create a steel bridge in mid air.