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“To me, achieving speed through efficiency has always been more elegant.” (aopa.org/aircraft/articles/2008/081230100mpg.html?WT.mc_id=090102epilot&WT.mc_sect=gan)

http://www.cleanmpg.com/photos/data/501/Rutan_Veri_EZ.jpgDave Hirschman - AOPA - Dec. 30, 2008

Modded Rutan designed Veri EZ – up to 100 mpg at slower speeds. 50 mpg at over 200 mph!

Why are more smaller private planes not designed for this kind of FE? -- Ed.

Pilots usually think of airplane flight performance in terms of gallons an hour—not miles per gallon.

AOPA member and aeronautical innovator Klaus Savier, owner of Light Speed Engineering based at Santa Paula Airport (SZP) in Southern California, has been setting speed and efficiency records for two decades in his experimental, Rutan-designed Vari-EZ—a plane that serves as a technology demonstrator for products that hint at possibilities for improving the efficiency of the GA fleet.

“Efficiency and speed go hand in hand,” said Savier, a German-born engineer, glider pilot, and composite materials expert. “They’re so closely related that it’s really a matter of emphasis. Do you go as fast as possible and disregard how much noise you make and fuel you burn? Or do you optimize the airframe, engine, and propeller for maximum efficiency? To me, achieving speed through efficiency has always been more elegant.”

Savier has altered his Vari-EZ and its Continental 0-200 engine by adding computerized fuel injection and ignition systems of his own design. He typically flies at 190 KTAS while getting a Prius-like 50 miles per gallon. If he slows to extend range, Savier’s mileage approaches 100 miles per gallon...

On a typical long-distance flight, Savier flies at an altitude of 17,500 feet, about 35-percent power, full throttle, 190 KTAS, burning 3.5 gallons of fuel per hour...

Savier tires of what he calls the aviation industry’s circular arguments about the merits of electronic ignition, computerized fuel injection, and lean-of-peak operations. Definitive answers, he says, have been provided by the automobile industry and verified in a variety of aircraft and engines over tens of thousands of hours.

“As long as you have magnetos, you simply can’t get the large spark from a big electrode gap or advanced timing you need for peak efficiency,” he said. “For all these guys that think magnetos are so great, I only have one question: Why don’t you put magnetos in your cars?” … http://www.aopa.org/aircraft/articles/2008/081230100mpg.html?WT.mc_id=090102epilot&WT.mc_sect=gan

Thanks for the find Louis!

The cost of government certification (and product liability insurance) to produce new aviation products has completely shut down certified aircraft improvement and innovation. Even the newest, most efficient production designs (Cirrus, Lancair) still use 1950s-designed engines - nothing new has been certified.

All efficiency work in private aviation is now done by people like Savier - in 'experimental' non-production homebuilts. The Experimental Aircraft Association runs "CAFE" (http://sustainabledesignupdate.com/?p=866)(comparative aircraft flight efficiency) races, which get tremendous results.

There is a core group of efficiency guys in the EAA and the Oshkosh fly in during the summer is the place to see them. It's the 8th Wonder.

There are several good efficient designs out there (mostly Scaled Composites or other fast glass like Lancair). There are also some efficient but Ugly designs (BD-4, Hertz 701)

Unfortunately, the classic J-3/C-172 light plane shape is inherently inefficient, although some can be overcome with tech.

Further, pilots are a conservative bunch and memory of early failures is hard to forget when your life depends on everything working.

Early electronic ignitions, Mode-S, synthetic oils in the 80s, and runaway product liability in the 80s all combine to ensure nervous pilots continue to fly with magnetos, AM radios, and leaded gas.

This is cool stuff! The Insight of the air! ;)

....Klaus Savier is an old buddy of mine. Back in the 1980's when I was the test/demonstration pilot for Glasair in Arlilngton, WA I was sent to Santa Rosa, CA each year (4 years straight) to compete in the CAFE 400 air efficiency race. Brian Seeley was head of the CAFE foundation. At these events I met many smart aviation people. I gave lots of rides in the Glasair to these folks, including Burt and Dick Rutan, Jeanna Yeager, Bruce Evans, Roy Lopresti (Mooney President) and others.

There is only 1 VariEze I know of, that can match or beat Klaus' rig. It is owned by Gary Hertzler. Google him if you're interested in another amazing airplane. Keep in mind, Mr. Savier's VariEze is HIGHLY modified, both airframe and engine. The Wheelpants are a special aero design developed at the Univ of Mississippi. The wheels & tires are small, 5" by 5". The retractable nose gear has special, super-tight fitting doors. The cowl and cooling system is an updraft, tightly baffled design that greatly reduces cooling drag. The canard is set at a slightly higher than stock angle of incidence to reduce drag at cruising speeds; but the landing speed is also increased. The wing-tip winglets are a custom design that optimizes speed and decreases vortices. Every system and item in the aircraft has been thought and re-thought, and modified to reduce weight. This has been a 20 year, serious undertaking. Very well sorted.

Klaus' engine is a Continental 0-200, 1964 vintage. It puts out 98 horsepower at 2750 rpm. He has experimented with many, many different wood propellers over the years. When trying for distance or efficiency records, he uses a super high pitched cruise prop that only allows a static runup of about 2100 rpm. This is similar to using a theoretical 6th gear in a 5-speed car. And it means that only perhaps 80 hp is available at full throttle while in the air, and the take-off roll is very long.

Notice the article states he uses 35% power and full throttle. This is because 17,500 feet is very high for a normally aspirated airplane like this, and with such thin air, only 35% power is available. A turbocharger would give him alot more speed at high altitudes, but at a heavy weight penalty and he would need to change pistons and greatly lower his engine compression ratio.

This airplane achieves close to TWICE the fuel efficiency of a stock plans built VariEze. The VariEze was designed by Burt Rutan in the 1970's. But every airplane is a trade-off, compromise. For example, this plane is NOT suited for short or rough fields. It needs plenty of smooth, paved runway. Also, it's not a heavy hauler; not much room for cargo or ability to carry the weight. Climb performance (in this case, lift) truly suffers in rainstorms, as the wing leading edge is almost critically laminar.

This kind of technology has been around, but good luck integrating much of it to General Aviation, production planes. Flatty is correct, product liability has killed FAA certification of lots of good ideas. This "liability" problem is described like this: back in 1981 a doctor flies his Beachcraft Bonanza into low clouds & fog, and runs into the side of a mountain. Lawyers find a way to directly implicate Beachcraft on some phony safety issue, and a jury awards 35 million dollars to the family of the deceased doctor. It is absolutely crazy! But the super-expensive insurance to guard against this type of lawsuit, is what raises the cost of aviation for everyone............

Hi Bill:

___Thank you very much for the details! While looking at the various Veri-Eze’s online last night, their GPH consumption at speed did not come out anywhere near 50 mpg let alone 100 mpg! They were in the 3.5GPH or more at 150 kts or thereabouts... Still great for a plane I guess but not even close to the 100 mpg barrier. This guy must be a pretty good pilot as well given your description.

___Also it is too bad the small plane manufacturers cannot use modern day fuel-injected and sparked engines. It seems like such a waste to be screwing around with 1950’s engine technology while our car engines are so much more reliable with 1990 through 21st century tech nowadays? I just have this picture of a lightweight 1.8L variant of the Honda Civic engine inside doing its thing at 40 to 60 HP output at a steady state cruise of 130 kts and consuming 1.5 to 2.0 gph while doing so. Better yet, a lightweight 2.2L iDTEC at 1.0 to 1.3 gph :D

___I do not know much about planes but I sure would like to see our modern engines placed into the Home Built or small prop commuters.

___Good Luck

___Wayne

Good thoughts, Wayne. There are primarily 2 manufacturers of small aircraft engines that have enjoyed widespread use in the past 50 years. Avco-Lycoming of Williamsport, PA, and Teledyne-Continental of Mobile, AL. The horizontally opposed 4 and 6 cylinder designs were developed in WW 2 and have changed very little! They are truly dinosaurs in their level of technology. But they are fairly lightweight and extremely reliable. They are low compression (aprox 7.8 to 1) and can use 80 octane gas. They use 2 spark plugs per cylinder. The plugs are known as the "massive electrode" type. Being air cooled, these engines are not very efficient for their size. This is partly because they are built with very loose tolerances to allow for heating & cooling expansion. When I use to fly the glider tow plane, it was extremely important to ascend slowly immediately after the glider cuts loose. Otherwise, you could thermoshock the cylinders and ruin them.

First of all, it takes more than 40-60 horsepower to adequately power a light plane. Unless, of course, it's one of those ultralights that fly very slow and land very slow. Some of them are not much more than powered hang gliders. Anyway, you need aprox 90-120 horsepower to propel a plane that carries 2 adults and weighs around 1100 lbs empty.

If there were alot more teenagers interested in aviation and small planes could make a huge comeback, new engine technologies might come forth with vigor. The future is likely with a lightweight, fuel injected, water cooled model. The Japanese could do it, and nearly did back in 1985, but the demand was just not there. Water cooled, high compression engines are SO much more efficient. Keep in mind with aviation, reliability, safety, and light weight is the name of the game....

The future is likely with a lightweight, fuel injected, water cooled model. The Japanese could do it, and nearly did back in 1985, but the demand was just not there.

billy:

Google "Subaru aircraft engine". There are many of these engines in homebuilts designed for 0-200 and IO-320 class engines. Reduction gearing is fairly simple and lightweight. One Dragonfly even had an UNgeared subaru in it. Yes, the prop went supersonic and no, it did not destroy itself.

As you have said though, product liability is a concern.

For the ground bound-

post-1996 product liability is limited to 18 years, before then it was unlimited. And indeed, people could and did buy 20+ year old planes with well-known model histories, crash them, and successfully sue the OEM for "product defects".