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Flying Solo by Design

A photo-rendered image of a hydraulically actuated CAM Plate.

Affordable Software Enables Engineer to Spread his Wings

Many engineers long to escape the nine-to-five grind and apply their talents as independent consultants. Toronto-based Gary Warburton is one who was able to capitalize on his specialization – thanks to affordable personal engineering tools – and fly solo.

Warburton’s highly specialized skills are not common, but are essential to the handful of companies in the world that require his particular brand of engineering services. He devises aerospace structural testing systems, having worked with such aircraft manufacturers as Goodrich, Landing Gear, Bombardier, Ultimate Biplane, and Diamond.

“In the industry, they call it ground testing, which makes sure that these systems work on the ground before they get in the air,” explains Warburton. “Sometimes we’ll make simulations to put massive loads onto the airplane, and see what happens during various extreme flight conditions which shouldn’t ever exist, but we still have to prove them out.”

When an aircraft company provides Warburton a test specification, he must create a test methodology that will deliver accurate performance data. Some performance data he can obtain from the client, but very often a new test requires the design of mechanical equipment that replicates the interaction of physical forces on the airframe.

These tests are essential for any aviation application. “I’ll work on anything from an Airbus A380, the double-decker jumbo jet built in Europe, down to the light five-seater aircraft I’m working on now,” says Warburton. He has even taken the principles of flight down to a smaller scale. Toy company SpinMaster enlisted Warburton to create a prototype for its line of AirHogs, the extremely popular remote-control stunt planes.

Model of a new canopy for the 20-300 Ultimate biplane.
The aircraft, currently under construction, will fly within
the next year or two. Modeled using a combination
of Alibre Design and Rhinoceros.

A Different Kind of Analysis

One thing that had to be scaled back while working independently was the budget for CAD. CATIA, a complex mechanical CAD package from Dassault Systemes, is a popular choice for aviation companies, but it ranks among the most expensive CAD software ever developed for a PC.

“Most of my customers use CATIA, and I am a certified CATIA operator. Unfortunately, I can’t afford CATIA because the price is a bit exorbitant,” admits Warburton. “When I went on my own, I started looking for a CAD package and came across Alibre Design. I started using it probably five or six years ago. From there, I started building up a sort of independent style of work, rather than being focused solely on CATIA. Now I work in Alibre Design, and deliver my data in CATIA-compatible formats.”

Alibre Design is a 3D parametric solid modeler that, even at its most expensive level, sells for only about 10% of the price of CATIA. The mechanical design package has formed the centerpiece for Warburton’s workflow for both analysis and test equipment design.

Warburton imports clients’ CATIA data into Alibre Design through neutral file formats such as STEP or IGES, or using Adobe’s 3D version of Acrobat to do the conversions. By exporting STEP files from Alibre Design, he can perform structural simulations on 3D models within standalone analysis programs.

For finite element analysis, Warburton exports the 3D assembly into Multiframe or ALGOR. “For the actual kinematics, I’ll use Alibre Motion, which does pretty good motion simulation,” he says. Alibre Motion, included with Alibre Design Expert, is capable of both kinematic and dynamic analysis of mechanical assemblies. Warburton simply establishes the parameters of movement and Alibre Motion animates the mechanism. By adding in hypothetical load information into the program, Warburton can calculate reaction forces and various other physical variables that influence the control surfaces of the airplane, like mass-moment or simple inertia.

Making the Numbers

To create designs of test machinery for his clients, Warburton relies on Alibre for the nuts-and-bolts of mechanical engineering. He uses another affordable modeler, Rhinoceros, when he needs to interface with the complex curves of airplane surfaces. To share his ideas with clients, Warburton takes advantage of Adobe’s universal lightweight file format, 3D PDF, which can be read with any Acrobat viewer. He exports a 3D PDF directly from Alibre Design and emails it to his clients.

Warburton’s clients send his completed equipment designs to outside fabrication shops. Once the machine is made, Warburton starts generating performance data.

“One of the last designs I created was for a wear test machine, used to determine the wear characteristics of steel and aluminum,” he explains. “I used Alibre Motion to determine the input torque requirement so that accurate motor sizing could be completed. This enabled the system to maintain the correct velocity and simulate an accurate wear profile.”

A New Independence

In recent years, the growth of technology has resulted in engineering tools making great strides in capability, while at the same time, affordable pricing of these tools from companies like Alibre has virtually eliminated the barrier of software cost for individual engineers who want to strike out on their own. Now engineers have the option of working for one company, or for many.

Warburton works for several clients, but generally focuses on one project at a time. Typically, the battery of ground tests needed for aircraft development is an extensive process.

“When you go out on your own, you’re very much dependent on the small jobs that come through. Now, those small jobs sometimes turn out to be several years worth of work, as was the case with my last customer. My current customer might be a couple of years worth, too – I don’t know at this point,” says Warburton. “When you don’t know how long projects will last, you can’t always go out and buy something like a CATIA license. Alibre Design has definitely helped me go out on my own, mainly due to the fact that I could actually afford it.”

At the end of the day, even for the most advanced analysis and equipment design there are affordable alternatives to the big-ticket software brands, which provide comparable functionality for far less money. And the affordable software that Gary Warburton has based his business on has passed with flying colors.