Inhoudsopgave van April 2024 - KITPLANES

For an engine long on the verge of viability but never quite making it over the threshold, the DeltaHawk is looking ever more real. It received FAA certification and the company will be pursuing firewall-forward packages for both production and Experimental aircraft. Perhaps more important was the late-in-the-year announcement that up-powered versions of the DHK180 are being developed. Two new variations of the 202-cubic-inch two-stroke diesel are planned: one with 200 hp and the other with 235. I’m told that fuel system changes and different turbochargers are responsible, meaning that the company is adding boost to get power. There are no internal changes as the DHK180 was “very conservatively designed” and didn’t need any. The subtext here is that it was built to grow, which from a marketing standpoint is…

For those considering an eXenos of their own, here is just a small excerpt from our test report with a few details on how it flies and handles: The eXenos is essentially a neutrally stable aircraft in both pitch and roll. Although weight and balance numbers indicate that it is in roughly the middle of the CG envelope with one 190-pound pilot on board, it behaves as if it is at the aft limit, and we recommend that care be taken in any loading that moves the CG further aft. Roll behavior is similar to many sport planes, and opposite aileron is required to hold a steep banked turn, whereas the pitch axis will stay wherever the pilot puts it, even if that means nose-high with decaying airspeed. In smooth…

I bucked the first rivet on my Van’s RV-10 project in October 2007. Barrett Precision Engines built my engine from a core, a decision that I have never regretted. I was also interested in the then-new E-MAG electronic ignition, but the engine was assembled and ready for the dyno before the six-cylinder units were available. Fast-forward a dozen years or so from the engine build to find my airplane flying reliably for more than 900 hours. During the recent holiday period, I was preparing to depart from our mountain airpark place (AZ82) when the run-up check revealed that the right mag was dead. Not rough, dead. Although I have more than 6000 hours in piston aircraft, this was my first failed mag. Back in the airpark hangar, it was too…

Last time we met, the question was if the engines of the future had already arrived. This time I’d like to turn around and consider the ’ol ball and chains we’ve been flying for decades. Lyconsaurs, in other words. Engineering Wise It’s popular to disparage these veteran engines, but from an engineering point of view they retain powerful advantages worth celebrating in our rush to the future. After all, should these engines fade from the scene, most of these attributes will be what we’ll miss and tell the kids about. Namely, the Lyconsaurs are large displacement, slow revving, simple engines with minimal parts count. These are good things (mainly). The big displacement means they make locomotive-like torque at low rpm, which translates into propeller-friendly crankshaft speeds so the weight, complexity…

On the back of my FAA mechanic’s certificate, there is a portrait of a man who most don’t know, but he was as important to the first airplane flight as the Wright Brothers themselves. Charles Taylor, the Wrights’ mechanic, designed and built the first successful airplane engine, a pretty important fork in the road of human development. At 12 hp, it was hardly a major powerhouse. But it ran long enough to get the brothers airborne and served as the basis of countless engines to come. It has been said that the 1903 Wright Flyer was the first homebuilt and by modern definitions, that fits. Not only did they design and build everything in the airframe for their own entertainment and education, they had that first engine built from scratch…

Securely holding small parts for machining is always a challenge. The solution may be to use a work-holding gadget such as a pin vise or peg clamp, make a custom fixture or, in the case of this month’s project, stack up two accessory devices—a rotary table and a 5C indexer—to accommodate the job at hand. Before deciding how to proceed, the machinist needs to consider the material being machined, how much needs to be removed and what the expectations are for tolerances and surface finish. These were the considerations I had to contemplate recently when deciding how to machine an arc on a batch of nut plates for a spinner backplate. Background Since moving to the high desert of northern Nevada a year ago, the wood cruise prop on my…

We started talking about diodes last month, those little critters that pass electricity in one direction and refuse to pass electricity in the other direction. Let’s talk about the “yep, maybe, nope” to this general statement. Before we do that, let’s talk about what makes a diode—what the physical makeup of a diode really looks like on the inside. To do that we first need to talk about silicon. You know, that silvery-gray stuff that Silicon Valley in the southern part of the San Francisco Bay Area is named for? First of all, silicon is a chemical element, that class of materials that isn’t composed of two or more elements. It is the second most common element in the earth’s muddy crust (oxygen is No. 1). It is about a…

Our February 2009 issue was assembled near the end of 2008 and had yet to reflect the mayhem ahead for the U.S. economy. In fact, your current editor in chief, who was in that role then, opined that the aviation industry was showing a bit of optimism. In retrospect, the industry had seen the first shocks of what would be called The Great Recession but hadn’t fully predicted the bottom, which would happen in 2009. Nevertheless, we continued on our merry way with the new Zenith CH 750 on the cover in bright yellow and blue. Author LeRoy Cook visited with the Zenith crew and reported that “the Zenith STOL CH 701 has always been a fun little kit airplane, with a loyal following and the potential for continued longevity.…

Ever consider what it might be like building an ultralight? But first, how do ultralights fit into the arena of “regular” Experimental airplanes like the ones featured here in KITPLANES? For those not familiar with the technicalities of an ultralight, allow me to briefly summarize the details of what defines an ultralight. Then we’ll consider how they complement their larger brothers. While you may hear pilots and builders use the term ultralight to describe a small, light aircraft in general terms, the FAA has very specific rules as to what constitutes an ultralight. Full details are spelled out in Part 103 of the FARs, but here are the highlights. An ultralight has a single seat (pilotonly capable), an empty weight of no more than 254 pounds and a maximum speed…

The fun of building and flying can go missing in the doing. Building becomes a series of tasks that mask the end game: an airplane crafted and flown by your own hands, for fun. Flying is reduced to checklists, ATC directives, numbers (and more numbers) and staring at gauges, monitoring numbers. That’s what I want the pilot doing when I’m parked in the cheap seats of a commercial flight, but it’s not why I pursue recreational aviation. Permit me shenanigans. Allow me some whimsy. Shenanigans, as I wrote in the March 2021 issue of KITPLANES, lend themselves to flying. Whimsy, the Oxford Learner’s Dictionary tells me, is in part “a way of thinking or behaving or a style of doing something that is unusual and not serious.” Whimsy plays well…

For the past few months, we have been concentrating on the primary cooling airflow and flow path for the air that cools the cylinders of the engine and carries away most of the waste heat generated by combustion of the fuel. This primary cooling system is a critical part of the engine installation, but the primary cooling flow is not the only cooling flow or internal airflow needed by the airplane. There are components and systems aboard, both within the engine compartment and the cabin, that require their own cooling flow to keep them within their operating temperature range. Cabin ventilation is also necessary and will require an airflow system that is entirely separate from the engine compartment cooling and ventilation airflow. Secondary Cooling Within the Engine Installation As we…