Alibre Design enables designer to reach new heights

To modify the design of an existing fiberglass glider and convert it into a jet-powered aircraft, Bob Carlton required a fully capable 3-D design program.

From the time Bob Carlton was five years old and his parents took him to see the Thunderbirds perform at Kirtland Air Force Base in Albuquerque, NM, he dreamed of an adventure in the air. Carlton said that watching the Thunderbirds was the most amazing thing he had ever seen, and it inspired him to learn aerobatics, putting on spectacular shows for millions of people every year.

Armed with that inspiration and a strong determination, Carlton, a rocket scientist for a major national laboratory, worked to make his dream come true in his spare time. He started flying hang gliders at the age of 19 and later secured a commercial pilot’s certificate, logging more than 2,000 hours and performing aerobatics professionally for the past 15 years.

For years, Carlton watched airshow performers and couldn’t believe people got paid to do loops and rolls, the stuff of fantasy for him. Now that he performs across the country, Carlton understands why they get paid. He says that the flying is the easy part, and the hard part is everything you have to do before you go up into the air.

Carlton is using Alibre Design to modify the design of his Salto (Latin for somersault) sailplane.

Just as in other industries, startup ventures in the aviation industry have the odds stacked against them, with a relatively small percentage of businesses surviving more than a few years. Besides pouring one’s heart and soul into these dreams, it takes much time and money before you make a profit.

Against the odds, Carlton has established himself in the business not only as a successful aviator and entertainer, but also as an aeronautics designer. In his current partnership with a Czech aerospace company, he is using Alibre Design to modify the design of his Salto (Latin for somersault) sailplane. The Czech company will build the engine to complete the conversion into a jet-powered plane. As part of the certification process for the Federal Aviation Administration (FAA), Carlton will also test pilot the plane.

Designing A Jet-Powered Aircraft

To modify the design of an existing fiberglass glider and convert it into a jet-powered aircraft requires a fully capable 3-D design program. Carlton uses an expensive 3-D design program at work, but he needed an affordable and powerful program to design his plane.

Carlton cannot get by with 2-D anymore. He models complex shapes, curves and thrust cones for his projects, all requiring full 3-D capability.

Since Carlton’s partner company would build the plane’s engine, he also needed to be able to import their files seamlessly and present professional-looking models to them. 

Alibre Design Goes Full Throttle

For nearly 20 years at his job, Carlton has used Pro/ENGINEER (Pro/E), which he calls a very capable but very complex program. “I’d hate to have to learn Pro/E if I didn’t have much time,” Carlton says. “Plus, you really need a dedicated IT person to network and manage it.”

Since Carlton needed a capable 3-D solid modeler at an affordable price, he looked around and found Alibre Design.

High-Powered, Low-Cost Solution

At a low cost, Alibre Design offers a solution that is powerful enough to design a plane in which the design is tested in the air. When the stakes are that high, you have to be extremely confident in your design software — here are some of the reasons that Carlton has so much trust in Alibre Design:

• Interoperability: While partnering with the Czech Republic to build his plane's engine, the Czech engineers sent STEP files to be imported into Carlton's model. Alibre Design allowed him to marry the two models together easily. When Carlton met with his partners, he was able to make a professional presentation, impressing the group with his results.

With ALGOR DesignCheck finite element analysis (FEA) software, Carlton verifies his designs with a first-pass engineering analysis to test the viability of the design in software.

• 3-D Parametric Solid Modeler: Carlton cannot get by with 2-D anymore. He models complex shapes, curves and thrust cones for his projects, all requiring full 3-D capability. "Alibre Design gives me the ability to design to a fine level of detail, and the devil is in the detail," Carlton says. It is hard to know, when beginning a design, exactly how much space to allow for each item. When Carlton was sketching his designs by hand in 2-D, he might have been almost finished when he found out that there wasn't room for the fuel lines, connectors and fuel pumps. "With Alibre Design, I can nail down the details on the fly and easily debug any of the details that aren't right," Carlton adds.
• Part Libraries: Carlton finds the TraceParts CAD part library extremely useful, saving him hours of design time. "The small parts take more time to model than the larger ones," he says. "Alibre Design provides many of the small parts you need and allows you simply to drop them into the design. This is integral to the system."
• Built-in Stress Analysis: With ALGOR DesignCheck finite element analysis (FEA) software available directly in Alibre Design, Carlton verifies his designs with a first-pass engineering analysis to test the viability of the design in software. "I just drop the files into the ALGOR FEA software to do the analysis of parts to make sure they stand up to flight loads and FAA requirements," Carlton says.

3-D Models That Instill Confidence

Alibre Design saves Carlton time by allowing him to do everything in a 3-D environment instead of starting in 2-D and transferring the work to 3-D.

Alibre saves Carlton time by allowing him to do everything in a 3-D environment instead of starting in 2-D and transferring the work to 3-D. The work needs to be right the first time. Cutting the fiberglass and finding it doesn’t work takes too much time and money. Alibre allows you to correct your errors in the design stage easily and gives you the confidence that the dimensions will work.

Instead of presenting designs sketched on a piece of paper to the Czech Republic and the FAA, Carlton could show them professional 3-D design and analysis models that look like the real thing. The professional quality of the work instills confidence in both groups. The Czech Republic knows they are giving the engine to someone who takes it seriously and knows what he is doing, and the FAA is more apt to approve the designs when presented with this level of quality.
           
For Carlton, each project is a stepping stone to the next. Since his next plane will be designed to use the same engine, he can save time and money by starting with the existing design files and modifying the plane.

What About Bob?

Bob Carlton began flying in 1979 at the age of 19. He has logged more than 2,000 hours in hang gliders, airplanes, helicopters and sailplanes. Since flying in his first professional airshow in 1993, Bob has continually added innovative performances to his repertoire such as barnstormin’ biplane aerobatics, helicopter sailplane tow, night aerobatics with strobes and pyro, and the world’s only twin jet sailplane. Bob is currently looking for a major sponsor to represent his Silent Wings Airshows. To learn more about Bob, his aircraft and his schedule, visit www.silentwingsairshows.com.