Diesels In The Sky: The Marriage of Light Aircraft and Diesel Technology

Diesel engines are all around us. Some in places we don't ordinarily expect. For example, I recently watched some railroad workers perform an oil change on a railroad car. No, it wasn't a railroad engine. It was a passenger car who lights, kitchen appliances and other needs were diesel powered. I never knew that. 

A day later I received an email with a link to an article about diesel engines in aviation. This, too, had some interesting surprises. The intriguing article by Trevor Anderson appeared on the Engine Labs site in December 2015. 

Anderson began by noting all the familiar places we find diesel to be the engine of choice. Heavy equipment, tractors, earth movers and their ilk depend on compression ignition power for a range of good reasons. But what about the other end of the spectrum, he asks. That is, what about the light weight, more delicate forms found in the aviation community?

Many of us might be surprised when we learn of the inroads of diesel in small aircraft. This article explains part of the reason this has been happening.

A little history is in order here. It's been less than 120 years since the Wright brothers took flight at Kitty Hawk. Diesel power has only been used in aircraft for a little over 80 years. It's hard to image the Wright brothers getting off the ground with those first monstrous diesels, though the reason diesel engines have been second string power sources for planes has more to do with the fuel than the engine.

This latter issue is actually what has incentivized the choice of diesel engines in more light aircraft today, the two primary reasons being lower cost and more widespread availability.

Anderson notes how light aircraft have historically run on Avgas, which is a gasoline-based fuel specially designed for aviation. Avgas chemistry is akin to racing fuel. It's available at U.S airports, but for aviators flying into remote areas of South America or other places off the beaten path -- places where pilots fly humanitarian missions in the Third World or remote parts of Australia -- it is not always available.

Diesel, on the other hand, is really available nearly everywhere. When you fly, your topmost concern is reliability. It's not like driving a car where you can just pull over and see what that sound is that your engine is making.

What's more is the simplicity of a diesel engine's design. With half as many moving part in a two-stroke diesel, you have half as many things that can go wrong.

There are, however, a few drawbacks to diesel, the author reminds us. He's not trying to sell us. He's just her to inform us of our options and why diesel in aircraft has been growing.

Avgas is designed for "the specific needs of aviation," especially in high altitudes. One of its properties is the ability to avoid vapor lock. That is, it's designed to resist becoming vapor in the lines, cutting off the flow of fuel to the engine. Diesel is subject to gelling, icing and the problem of microbial growth in the fuel.

The Arctic regions and dense tropical rainforests will present problems for diesel planes that Avgas-powered engines will shrug off.

Naming Names

There is only one left. Diesel-powered Junkers 
took to the air during WWII

In the latter part of this article the author begins by taking us back to the first diesel-powered aircraft, the German-engineered Junkers JU-86. The plane was produced specifically for the Luftwaffe initially. It had a variety of looks and was the first to have diesel engines. It was a twin engine bomber and transport craft. 

A unique feature of these engines is that they had vertically opposed six-cylinder, 12-piston, liquid cooled, supercharged engines that generated 868 hp each. It could climb 900 feet per minutes and carry 11,000 pounds. Not too shabby.

Nowadays there are a number of aircraft builders who use diesel power in some of their planes including Diamond Aircraft Industries, which is discussed in detail. Diesel engine suppliers are also noted, including unique engines like Superior Gemini, DeltaHawk and Centurion. The big two engine builders, Lycoming and Continental, primarily make Avgas powered engines, but have also produced some diesel engines on a limited scale.

The article has lots of photo and goes into more depth on the diesel engine builders near the end. You can find the full story here at EngineLabs.

Heart-Stopping Power: Gale Banks' 1200-HP Tri_Charged Duramax

When it comes to motorheads, the hunger for power seems near universal. According to Wikipedia, hot rodding was birthed in Southern California in the late 1930s. People raced modified cars on dry lake beds northeast of L.A. with rules established by organizations like the Southern California Timing Association (SCTA). Unofficial street racing took place anywhere where you had more than a handful of teens and a stretch of straight, flat road.  

Most of these teens grew up and moved on, pursuing careers, supporting families. Then there were the others for whom the experience of speed and power ignited a passion that became the fuel that powered their careers. One of these  boys with an aptitude for mechanics was Gale Banks, now president of Gale Banks Engineering. Three parts engineer, one part "mad scientist", Banks has spent a half century tinkering with technology, keenly focused on improving the internal combustion engine. His special interest has been diesel engines.

To give you an idea of just how far Gale Banks is willing to go to extend the capabilities of diesel engines, Greg Acosta wrote this story for EngineLabs.com: More Power With Less Boost: Banks 1,200-HP Tri-Charged Duramax.

One of the things that makes this article so significant is that the author is not only writing about a briilliant engine builder at the height of his powers, we're encountering the rare transparency of a man who is sharing everything openly. Banks has been part of a world where secrets are the norm. Competition means finding an edge, not sharing your edge. 

The Duramax engine Banks has been incrementally improving is suitably named "Mad Max". It's something he's been focused on and fine tuning for two-and-a-half years. In this article we don't just read details about the power this setup can achieve. In addition, Banks provides a breakdown of what all the readouts mean, and what the dyno data really means. As Acosta puts it, "In a world where data is hoarded and protected like the gold in Fort Knox, Banks is freely sharing not only his findings, but explaining the findings as well."

For Banks, one of the key metrics is Manifold Air Density (MAD). Since it's a Duramax he's been playing with, could this acronym be the secret to why he calls this engine a Mad Max?

Acosta writes, Using his preferred metric of Manifold Air Density, Banks breaks down the amount of air he needs to reach his 1,200-horsepower goal, and how, exactly, it will be measured on the dyno. “Manifold Air Density is the best indication of the engine’s power potential. You can forget about boost pressure, because it’s part of the MAD calculation. Manifold Air Density is the bottom line,” says Banks.

* * *

The engine was originally built for a Monster Truck. If you'veever wondered what those monsters had under the hood, this story will peak your interest on that level, too. The photos draw you in, but the details are what make this a valuable article to be bookmarked by any serious gearhead seeking to learn how to make dyno adjustments for maximum diesel power. 

Here's the link to the full story:

More Power With Less Boost: Banks 1,200-HP Tri-Charged Duramax

https://www.enginelabs.com/news/more-power-with-less-boost-banks-1200-hp-tri-charged-duramax/

 

About Gale Banks

Gale Banks is an American hot rodder, drag racer, engineer, and entrepreneur who grew up in Lynwood, California. His company, Gale Banks Engineering, sells performance parts for automotive and marine engines. It specializes in diesel engines, and high end cutting edge equipment, performance parts, and auxiliaries

--From Engine Labs today