What Our Members Are Building/Restoring — Colorado GSport

By Gary Leake, EAA 1264445

This piece originally ran in the July 2022 issue of EAA Sport Aviation magazine.

GSport was conceived about 18 years ago during free time while deployed. Having always enjoyed building things and putting my own spin on it, when life finally allowed the pursuit of a homebuilt, the number one goal was to build something different. Whether it was better or not than other designs didn’t matter as much as the fact that it was unique. I could learn new things and have fun.

My father made sure I got an early start with flying models. He was always modifying existing designs, so I grew up in that environment. The majority of models (free flight, control line, RC) were my own designs, just to be different and explore some what-ifs. During high school while helping him build a Steen Skybolt (N22GL), I came to see a full-scale airplane as little more than an overgrown model, subject to the same laws and principles, just bigger pieces.

I sought design and stress analysis help for GSport from a local pilot who had designed and built two of his own. Like many skills learned in building, there aren’t any secrets; it’s just a matter of practice or playing with the numbers until you get something you like, and go with it. Wood was the material of choice because I was comfortable with it.

Besides a host of EAA how-to manuals handed down from my father, knowledge was combined from plans for a Skybolt, Emeraude, Fly Baby, and RV-6, for common design principles and material sizing. Construction began in Asia, where I ran out of space, moved to Europe, where I ran out of materials, and then returned stateside, where I have made steady progress ever since.

Since I enjoy building, I was willing to sacrifice ease of construction to save weight. Ribs could have been quickly routed from plywood, but a built-up truss rib, each made of 64 pieces, is lighter and stronger. As another example, due to compound curves in addition to a 90-degree twist, the turtledeck stringers were laminated, and thus they are passive in their complex shape, which allows for a lighter supporting structure but, again, more work.

GSport has a lifting-body fuselage inspired by the Hiperbipe, a childhood favorite because it was different; a 50-inch-wide cabin to fit two people in winter coats; all-flying tail surfaces; full-span flaperons capable of reflex, melding ideas from other designs for the mixer; and multiple other aerodynamic features incorporated from those handed-down manuals. The decision to install a ballistic chute (Galaxy GRS) came about from watching multiple “save” videos, many at low altitude, which convinced me this was the best option, especially with passengers. I learned how to roll the canopy bow (times two!) to fit the cut-down RV-14 canopy. The firewall “just happens” to match that of an RV-6 — I really didn’t want to do that much glass work from scratch. ULPower 350iS with an Airmaster constant-speed electric prop. Grove landing gear, wheels, and brakes; Trig comm and ADS-B; Stewart Systems covering and paint — all done in an open basement with no complaints from a very sensitive spouse! A steam gauge panel rather than glass seemed more appropriate for an open-cockpit design.

I ended up making two or three of many things. Do your best on paper, but sometimes it’s that last 10 percent in the flesh that reveals opportunities for improvement. Build time was 5,400 hours, not including a ridiculous amount of time just staring at it wondering, ‘How to … ?’ or even more time agonizing over, ‘Put it here or put it there … what if I need that space later?’ But finally you make a best-guess decision, increasingly confident that if it creates a problem later, it could be dealt with. Kit builders should appreciate all the choices they don’t have to deal with.

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I was challenged many times but never overwhelmed. Inexperience, however, led to some poor choices, such as having the hydraulic ports for the brakes drilled on the bottom of the gear so brake mounting could go either way, only to realize years later that I had inadvertently lost a prime jack point for the gear. Also, don’t try to mix and match different brands of instruments and senders trying to save money; it won’t work. After 15 years of building, GSport finally received its airworthiness certificate. Many thanks to the members of EAA Chapter 72 who provided knowledge, guidance, tools, and encouragement, and especially my wife, Kim, who continues to tolerate my ‘girlfriend.’

After a 15-year hiatus from flying, I got current and got some time in an RV-8, which proved to be a good match. I finally ran out of excuses for the first flight, not without a great deal of anxiety, mixed with confidence that all the mechanical issues had been addressed, and a sense of responsibility for a new design, not wanting to put anyone else at risk. Other than a high oil temp and needing some rudder trim, the first flight was an uneventful success. GSport is currently in Phase I, and I’m very pleased so far.

Many of us may only get one chance for something like this. I’m thankful for the freedom we have in the experimental amateur-built realm to modify and customize, or pursue something entirely different. GSport embodies quite literally the experimental side of sport aviation. It’s an overgrown model that satisfies a primal itch for something different. I’m still learning, and still having fun!

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