What is GizmoCopter?
GizmoCopter is a 4-rotor model helicopter design intended to carry
and test flight control electronics and software built by the
Flight Control Team of ERPS.
How Did It Get a Name Like "GizmoCopter"?
The ERPS Flight Control Team had been planning that any test article
built by the team without needing to bother the other ERPS teams
(like Propulsion, Structures, etc.) would be a part of the G.I.Z.M.O.
test series.
That's a whimsical acronym
which is intended to represent the hopeful future result
of good testing:
Gadget Insuring Zero Mashed Orbiters.
ERPS rocket engine development delays in 1999,
and a search for adequate flight software testing methods,
led to the idea of 4-rotor model helicopter test platform.
Naturally, since it would be the first of the GIZMO series,
this helicopter had to be GizmoCopter.
We checked and found that there were no entries for the name in the US Patent & Trademark Office's database, no registered domains and not even any web page containing the word according to the major web search engines. That's a lot better than any other name any of us had come up with so we went with it.
ERPS now claims a trademark on the name "GizmoCopter"
in order to preserve its own right to use of the name for this project.
What Are the Specs for GizmoCopter?
Specifications are subject to change by the projects volunteers
for technical or other reasons.
We're using a Linux-based PC/104 computer for the flight computer. The GizmoCopter frame was custom-machined by Eric Wilner, one of ERPS's machinists. We're using four 12-inch fixed-pitch model airplane propellers with model airplane racing motors.
Two of the propellers are counter-rotating to neutralize engine torque forces on the vehicle, and allow us to use differential throttling of the forward and counter rotating motors for roll-axis control and stability.
As contestants in an Embedded Linux Journal contest for demonstrating embedded Linux systems, we are committed to release the source code for GizmoCopter. We formed the OpenVTVL Project in cooperation with Armadillo Aerospace of Dallas (another amateur rocketry group focusing on VTVL flight) to publish our source code.
More details will be posted later.
What Do You Intend to Learn from GizmoCopter?
We want experience with software to control "powered lift" (hover) flight,
which will be needed for future ERPS projects.
We need a small non-rocket test vehicle which can be operated safely
in a park or field near where participants live,
instead of driving for 2+ hours to the rocket test range which
ERPS uses.
GizmoCopter's on-board computer will manage differential thrust of the four helicopter rotors. This is similar to the hover flight capability that is being designed into future ERPS VTVL (vertical takeoff, vertical landing) projects which will all use differential rocket thrust for control...
Currently there are no plans to make a business out of GizmoCopter.
But ERPS has been known to spin off businesses before so who knows what will happen? ERPS has used before the funding methodology of licensing ERPS technologies to businesses spun off by its own volunteers. The licensing fees are used to fund further ERPS research. Usually those plans don't hatch until the technology is more-progressed in design or development than this one is.
If you want something like GizmoCopter but smaller and as a model aircraft kit, we used to suggest that you take a look at the "Roswell Flyer" by A.F.O.T., but AFOT is no longer in business. However, enthusiastic owners have documented it quite well...
Although the concept is not new.
An 8-rotor helicopter model was built and flown
in the early 80's as a scale model
for military skycrane-follow-on helicopter simulations.
It was featured on the front page of Popular Mechanics magazine
at the time.
What is GizmoCopter Using for its Flight Control Computer?
It's a
PC/104
embedded computer with an x86 processor.
The operating system is
a real-time variant of Linux.
The flight control software is custom-developed by ERPS.
Whenever possible, software infrastructure code is contributed back
to the Open Source community,
except in cases specific to rocketry or guidance systems.
This is exactly the same computer as for ERPS's future VTVL rocket designs. If it had not been for GizmoCopter's purpose to test this computer before installing it in the rocket, this would be complete overkill in computing power for a 4-rotor model helicopter. The processing power of this computer is the same as was used by McDonnell Douglas for the DC-X (the world's first VTVL rocket), which is more than it currently takes to fly the Space Shuttle.
Hobbyists who wish to experiment with computer-controlled model aircraft
would be well advised to start with smaller, lighter processors
like a microcontroller.
Can I Help?
If you would like to help with ERPS and GizmoCopter, please join the
ERPS mail list
and express your interests to the group. Lots of different kinds
of volunteer activities are needed, not all of them technical.
ERPS accepts new volunteers in technical and non-technical areas, such as rocket engine design, electronics, software development, documentation, composites construction, logistics or machining parts. Work at the test site can include digging, pouring concrete, security, installing/repairing plumbing or preparation of food for the other volunteers. For our safety crew, ERPS can always use more people with firefighting or CPR/EMT/etc training. (We give veto power over any safety issues to our Safety Officer. ERPS officers will back up those decisions 100%.) Amateur Radio operators are needed to assist with communications at the test site too.
Or if you don't know where to help, watch the mail list discussion (or attend our meetings if you're local to Silicon Valley) and look for a place you'll fit in. But be careful in that case to restrain your enthusiasm enough to avoid getting in the way of the current volunteers' work. Suggesting too many changes or asking too many questions at once (instead of starting by observing) are problems exhibited by some enthusiastic new participants.