Tabla de contenidos para March 2025 en KITPLANES

WE HAVE A FEW CHANGES around here that are worthy of mention. First of all, I’m excited to start a different kind of build series that Paul Dye, our esteemed editor at large and former editor in chief, and I have been talking about for some time. As a multiple builder—the F1 Rocket he’s constructing is his fifth—he has a very experienced and highly nuanced view of homebuilding aircraft. He has, as the cliché goes, been there and done that. The series, which starts on Page 52, is called Eating the Elephant. In typical Paul fashion, it is what it sounds like: an explanation of ways to reduce the longterm and marvelously complex task of building an airplane into digestible bits, a way of putting one foot in front of…

A plenum on a piston engine aircraft is an enclosure around the engine that helps air circulate for the purpose of cooling. They are typically made of aluminum or fiberglass and are designed in conjunction with air inlets and baffles to hold the air around the engine at a higher pressure than the surrounding air. This pressure difference allows the air taken in from the inlet(s) in the cowl to move evenly past the engine’s cooling fins at a speed and volume that keeps the engine at an appropriate operating temperature. • The cowl’s air intake(s) must be sized to allow enough air for sufficient cooling but not so large as to unnecessarily disrupt the airflow over the cowl and increase drag. The overall shape of the inlet can also…

ONE OF THE MOST COMMON questions I get: What is the difference between the Zenith 750 Super Duty and the 750 Super Duty Xtreme (SDX) I’m building? Basically: What makes this 750 SD “Xtreme”? The short answer to this is: The crazy builder (me) is taking everything about this build way too far. A better answer might be that the 750 SDX is still evolving. But I have decided it is time to make a list because there are many ideas and customizations I want to do with this airplane that will make it unique and, hopefully, better for my personal missions. Here’s the list. Extreme Power to Weight This one is simplified mainly by ULPower. Remember that the base Zenith CH 750 Super Duty has been flown with a…

IT IS COMMON for a pilot new to the homebuilding world to come onto an internet forum and ask something like, “I really like those RV-7s, and I’d love to have one, but I am trying to decide if I should build a new one or buy one already built. Can anyone help me with that decision?” That’s an incredibly easy question for experienced builders to answer. Without a doubt, the person should start shopping for a completed airplane. Because building an airplane is not a hobby. It’s not something that you pick up casually to do in your spare time between household chores, fishing trips, time with the family at the cabin or vacations. Building an airplane is a commitment to spending literally thousands of hours in the workshop…

FLAT TIRES SEEM to come in clusters. You can go years without getting one, then for some reason, “boom” (actually, more like “psssss”), more flats in a month than a year or years. Just days after I finished dealing with my nosewheel flats (see KITPLANES November/December 2024), a local RV-12 pilot we call Bob #1 (I am Bob #2) got a flat on his port side main one morning while taxiing out for a flight. The flat rendered the plane immovable, so he fetched a wheel dolly to put under the offending wheel. During the process of hoisting the wheel onto a dolly, something didn’t go quite right and the next thing he knew, the wheel pant bracket had disassociated itself from the axle. What gave way were two AN3-40A…

NOW THAT THE WEDDING is behind us and house projects have slowed, Brian and I have more time to focus on what matters most—airplanes. Last October we swapped the Hickman family Cessna 140 for Brian’s older brother Jeffrey’s Glasair Sportsman and have been taking advantage of it, even if our mission is just to fly to Salem for a bite to eat. The C-140 needed an annual and thankfully Jeffrey got his A&P last year so scheduling maintenance has gotten easier. Brian and I flew the C-140 from our home in Canby, Oregon, to Frontier Airpark in Lake Stevens, Washington, where Jeffrey lives. Unfortunately Brian and I didn’t get to fly the Cessna much during the summer but were quickly reminded it’s 77 years old—our squawk list grew the farther…

“IF YOU COULD HAVE any dream air vehicle, what would it be?” asked David. “Including something that’s not available?” replied Sara. “Yes.” “OK, it would be a two-place vertical takeoff and landing vehicle I could have right here in my driveway. Not a car, mind you, but a VTOL. With 100% automatic flight. I’d get in it, enter my destination and then sit back and read the newspaper. Or watch the scenery. How about you?” replied Sara. “That doesn’t sound fun at all. I’d find a Piper Cub and fly it on warm sunny days. Total bliss. No artificial intelligence or computers needed except my own feeble brain.” The ChatGPT idea is all wrong. We don’t need help writing term papers. We need help flying. Or no help flying. I…

WARBIRDS ARE EXPENSIVE. Expensive to buy, expensive to restore and expensive to fly. For all that, you join a privileged cadre of pilots/owners who can walk with a particular swagger—not unearned in most cases—and you get premium parking spots at most airports and events. But for most, those expenses make owning and flying a warbird a fantasy. For this reason, kits and plans for warbird replicas have been part of the homebuilding landscape for almost as long as homebuilding has been around. Varying in scale, weight and power, some mimic their progenitors better than others. What is generally true about all of them, however, is that they are homages to the classic fighters of the two world wars—Sopwith Camels and Fokker Triplanes from the first and Mustangs and Spitfires from…

One reason James Aircraft’s cowls are so popular is the company’s use of Parabeam fiberglass. Parabeam invented woven sandwich fiberglass and, in addition to its aviation uses, you can find it in mass transit floors, ceilings and doors, watercraft decks, panels and bulkheads, and in building and architectural elements. • Unlike conventional cross-weave fiberglass cloth, Parabeam consists of two bidirectionally woven deck layers that are joined vertically with braided pillars. (See illustration.) The pillars act like springs and push the deck layers apart to a predefined height. • When you apply resin to Parabeam, the pillars’ capillary function saturates the glass yarn without filling the empty space between the deck layers. This avoids wasteful resin oversaturation and creates a permanent hollow space between the layers. (This space can even be filled…

MY CUSTOMER RELATIONSHIP with Crow Enterprizes (their name back then) goes back 20 years to when I was building my RV-8. I was building my first real aerobatic airplane and, of course, that meant I wanted a “real” harness system with military-style rotary buckles. Some internet searching quickly pointed me to racing harnesses—the military buckles had military price tags, so they were out. The popular aerobatic harnesses at the time were all using the old reliable latch buckles. But the racing world had cool harnesses and further research showed me harnesses from a couple of manufacturers. But Crow stood out in terms of price and features. I called and told them that I wanted harnesses for an airplane and instead of hanging up on me they asked to know more—and…

ONE REASON YOU MIGHT enjoy reading KITPLANES may be that you appreciate aircraft that possess the benefits of the Experimental/Amateur-Built category. This group includes the kits and scratch-built projects that create airplanes with some very special benefits compared with their certified counterparts. These benefits include the ability to perform your own annual condition inspections and forever allow you to change your mind about what avionics, engines, propellers and other components this aircraft should have. Not so easy with a certified aircraft! A certified (factory-made) aircraft typically cannot be altered from the way it came from the factory (in some cases the FAA does allow for approved changes to certified aircraft by submitting special paperwork that the factory must endorse). As the owner—not just the builder, by the way—of an Experimental,…

IN THE LAST ISSUE I spoke of nuclear certified string, hoping to convey that some airplane parts are just parts. Bronze bushings, PK screws, NPT fittings, fiberglass cloth, you get the idea. In this issue I’m staring design specific airplane parts straight in the eye and calling them out as frauds. OK, not frauds, I got caught up in the moment, but also not mystical items infused with the ability to fly by secret means. A design-specific airplane part is a combination of three things: a specific material (or combination of materials) in a specific shape and labor. That’s it. You know what that means? You don’t have to wait to get a replacement for a kit part you mussed up, nor do you need to permanently ground your one-off…

ONCE THE AIRPLANE has been powered up and static testing of its systems is complete it is time to move on to taxi tests. Taxi testing starts when the airplane first moves under its own power and ends when the airplane is determined to be ready for its first up-and-away flight. Slow Taxi The first phase of taxi testing is done at low speed on the ramp or taxiway no faster than normal taxi speeds. Engine power is low, never more than what is needed to move the airplane at walking pace or slightly faster. Higher-power testing will happen later, on the runway. These tests will be the first prolonged operation of the airplane with the vibration from the engine. After each excursion, it is a good idea to check…

If you think building an aircraft is fun, Jimmy Cox says help some teenagers learn to put one together for an even more enjoyable and satisfying experience. “I look forward to every Saturday when I get together with my Rockdale Tiger Flight,” said Cox, the owner of James Aircraft. The group is a 501(c)(3) nonprofit he started about a decade ago to introduce kids to aviation and aircraft construction. “We’re in a small Texas county of only 25,000 people, so very few of our kids have a chance to learn about planes firsthand,” says Cox. “I started doing this because I read accounts about how much of a difference it can make in a child’s life to give them hands-on opportunities. And, I’ve seen some results with the kids we’ve…

IF YOU’LL JUST PAY ATTENTION and listen to her, Lady Fate always finds a way to tell you things that portend your future. Sometimes it’s a “grab you by the nose and kick you in the pants” happening that tells you you’ve run outta your nine lives and it’s time to take a long think about your future. Think of the fat lady singing her last aria in the opera, tripping and falling head-first into the tuba in the orchestra pit. Now that’s a surefire attention getter. She should have been listening. At other times it’s a gentle nudge from Madame Fate trying to help you make the right decision. But, unfortunately, sometimes a subtle nudge just doesn’t quite do the job. You need a nudge that’s a real attention…

EVERY PILOT WHO has ever experienced icing conditions will remember their first time. Something particularly alarming comes when experiencing icing conditions in a conventional multiengine propeller aircraft. When the prop deice is activated, it sounds and feels like someone is driving golf balls into the side of your aircraft. It is quite disturbing—even when expected. I don’t want to get too deep into the weeds of the chemistry and physics of icing conditions, as they are complex. What I would like to do is share a couple of examples of real-world experience. Jackson Hole My first airliner job was flying the Fairchild Metroliner around the more mountainous areas of the Western U.S. I will never forget one winter morning in 1987 flying into Jackson Hole Airport (KJAC) in Wyoming as…

We’ve all heard horror stories about the prices of certified aircraft parts, but, I’ve found, they pale in comparison to the cost of a particular motorcycle company’s branded oil filter. Thankfully, there are options. Let’s look at them and see how they compare to E/A-B parts. Parts Manufacturer Approval (PMA’d) Parts A type-certified aircraft owner can’t always purchase parts directly from the manufacturer. Piper doesn’t make new Cub boot cowls just as Ford doesn’t stamp out Model A fenders. To keep Cubs serviced, Piper licenses others to make boot cowls. Those are known as PMA’d parts. A PMA is necessary for someone other than the type certificate holder to manufacture, for resale, parts for certified aircraft. The FAA describes the PMA design approval as such: “The design approval phase of…

IT TAKES MANY THINGS to build an airplane to completion. Time for sure; money, of course. Some skills, many of which you learn along the way. But among the greatest of a successful builder’s attributes is an unshakable belief in tomorrow. Indeed, faith in the future must be the strongest motive, the greatest inoculation against the torrent of life’s impediments, the very reason to “take arms against a sea of troubles, and by opposing end them,” to borrow from the bard. Certainly there are reasons not to build every time we think to pick up our tools. Fatigue, friends calling, boredom, the heat, the cold, the indecision, the parts that didn’t arrive, the fear of getting it wrong, the call of a perfect sky begging us to fly the other…