While you can't get this one any longer, about 20 are flying and some pop up on aviation sale listings. In its day — before Valley Engineering decided to cease building and focus on their Culver (wood) Prop enterprise — Back Yard Flyer attracted wide interest, rising steadily to be one of our Top 50 videos of about 1,000 produced.
Part of the reason for keen interest was an airframe that quickly folded in a unique for easier storage. Built primarily of welded aluminum, the airplane looked tough yet managed to stay within Part 103 tight constraints.
Another reason for strong interest in this simple flying machine was its four-stroke engine, modified from a Generac engine. At the time, 2010 or so, four stroke on genuine Part 103 ultralights was extremely rare.
Put together, the welded aluminum structure with its folding wing and dependable power and, presto, you have Backyard Flyer.
I refer to "the Flying Farmer," Gene Smith. Every year it seemed he would bring a new variation of something he casually called his backyard flyer. One year, after being challenged by weather the prior year, Gene decided not to fly to Oshkosh. With help from his son Larry, Gene created the current last iteration of the Back Yard Flyer seen in nearby images.
The particular sound people remember was a four stroke power plant. By itself, that was very unusual 10 or 15 years ago yet what made it unique was that Valley engineering started with a Generac-brand power generator engine, modified it significantly, and ended with a four stroke engine that could be used on this very light airframe and qualify for Part 103.
I never weighed the finished and I'll be it was close to the line but Gene and Larry said it weighed "251 pounds even with tricycle gear." One reason why it looks heavier than allowed is the larger-diameter welded tubing that comprises most of Back Yard Flyer. Most observers are fooled because you expect welded to be steel (generally thinner diameter tubes). Welded aluminum is relatively unusual but the Smiths report it made a robust airframe able to handle the bigger engine.
Gene proved the naysayers wrong back in the early 2010s — yes, pilots complained about the cost of airplanes then, too. His Backyard Flyer could qualify for Part 103 and could be purchased for less than $20,000. In early 2024, an equivalent amount of dollars would price Back Yard Flyer at $28,000. and for that, most would consider it a bargain.
Gene, the "Flying Farmer," faithfully flew his circuits of the Ultralight Area pattern accented by a throaty, guttural four-stroke sound that did not mimic the ubiquitous Rotax 582 that was king in the day. Gene's Generac made an energetic flyer that could easily get in and out of a generous back yards.
"After Grandpa (Gene) passed away in 2016," Alaina Lewis wrote, "we decided we couldn’t offer adequate customer support for the plane. We still have all the tooling and jigs and have no plans to sell the design. We will continue to offer customer support for anyone who has a Back Yard Flyer or any of our engines."
"We appreciate all the support that has been shown for our little plane through the years," Alaina wrote in 2019. "Grandpa loved designing and building and we were so grateful for the opportunity to get a few planes out into the aviation world and the opportunity for him to live out his aviation dream."
She continues the family enterprise making beautiful wood props.
Just six years ago, I interviewed 
Over many years, one of the most consistently requested aircraft is Back Yard Flyer. Even the name sounds affordable, doesn’t it? While you can’t get this one any longer, about 20 are flying and some pop up on aviation sale listings. In its day — before Valley Engineering decided to cease building and focus on their Culver (wood) Prop enterprise — Back Yard Flyer attracted wide interest, rising steadily to be one of our Top 50 videos of about 1,000 produced. Part of the reason for keen interest was an airframe that quickly folded in a unique for easier storage. Built primarily of welded aluminum, the airplane looked tough yet managed to stay within Part 103 tight constraints. Another reason for strong interest in this simple flying machine was its four-stroke engine, modified from a Generac engine. At the time, 2010 or so, four stroke on genuine Part 103 ultralights was extremely rare.
Proving the naysayers wrong (again!) were at least two intriguing Part 103 airplanes you can buy and fly today for less than $20,000. That's well the under the average price of a new automobile for a ready-to-fly aircraft with desirable features, not a stripped-down machine that no one really wants. I wrote about Terry Raber's lovely little 
If you've ever visited AirVenture's Ultralight Area, odds are you saw a pilot known as the "Flying Farmer" doing circuits of the Ultralight Area pattern. Seemingly a different (though vaguely similar) aircraft would do pattern flights each year accented by a throaty, guttural four-stroke sound that did not mimic the ubiquitous Rotax or the smooth Jabiru, or even the also-distinctive-sounding HKS. Powering the Flying Farmer's aircraft was a Generac generator motor converted to airplane use. It pulled aloft a welded aluminum structure under a semi covered, or semi enclosed, aircraft that also didn't imitate any other airframe you saw. They all looked to fly energetically.
I refer to Gene Smith (the "Farmer") and his 
Now Gene's son, Larry Smith, is the front man for their newest-yet Backyard Flyer, a legitimately Part 103 aircraft that looks as solid as much heavier aircraft — "251 pounds even with tricycle gear," said Larry. Welded aluminum permits larger diameter tube-frame construction that has a reassuring beefiness to it.
Perhaps the most unusual feature of this not-like-the-others airplane is the swing wing. Four bolts allow movement on a "turntable" so the one-piece wing pivots 90 degrees to sit over the tail and protrude beyond the nose. The "swing wing" requires a 30-foot trailer but would truly be useful in a crowded hangar as it measures only 83 inches wide. Aileron disconnects took a couple minutes; the whole process didn't consume five minutes.
