Industry News

Power and speed—two of aviation’s touchstones—have been pursued as long as there have been airplanes and people willing to throw money at them. Aftermarket designers have hung ever-larger piston engines on factory airframes, with varying levels of success, for decades. By the 1980s mod shops were bolting on turboprops in place of reciprocating engines and achieving impressive speeds, despite the challenges of assuring the airframe could handle the horsepower and juggling the fuel/payload equation on the small airframes. The small size and high power density of turbine engines makes them attractive, as does the increasing difficulty of obtaining avgas outside the U.S. However, there’s no free lunch; jet fuel weighs .7 of a pound per gallon more than avgas. That adds up because turbine engines have higher fuel specifics than piston pounders. For each horsepower output, the turbine uses more fuel than does a piston engine. The result is that the light weight of turbines is offset by the need to carry more, heavier fuel to achieve reasonable range. This becomes particularly acute in the relatively small, piston-powered airframes, and their correspondingly small wings and fuel tanks, designed for piston fuel consumption specifics.

Flying a Piper Archer II, I drooled over the gas mileage of your best LSA pick, the Pipistrel Virus. So I flew to the SLA showcase in early 2012 at Sebring, Florida airport to get a closer look at the Virus. Once I got into the pilot’s seat, I wondered who would buy this airplane? To me, it is downright dangerous, as the main wing spar intrudes into the cockpit, crossing just a little bit in front of and above your head. (I am only 5 feet 9 inches.) In a not-too-perfect forced landing, your head could easily be crushed by the impact with the main spar. I mentioned my concern to the salesman who responded that, “You lean forward in front of the spar just before impact”… then I surmised the back of my head could be crushed as the indeterminate G forces toss my body and head around in milliseconds, seatbelts notwithstanding.

Following our July article on folding bikes, Woody Saland sent us the letter at right about his experience with electric bicycles for transportation at airport destinations. I asked him to send me a couple of photos and here they are. I wanted to show how he’s using this bike as an interesting juxtaposition to this month’s article on lithium-ion batteries. As he explains in his letter, this bike is a folder that’s also propelled by a small electric motor powered by a rechargeable lithium-ion battery pack.

For the great wide world of transportation, the lithium-ion battery is the shining city on the hill, that pivotal bit of technology that will have us whizzing around in silent cars banishing the evils of carbon dioxide. For aviation, lithium-ion is both an enigma and an opportunity. To understand both, you need only to grasp three numbers: 50, 150 and 1700. The opportunity part resides in the first two numbers—a lead-acid battery’s energy density is about 50 Wh/kg, a third or less than that of the typical lithium-ion’s 150 Wh/kg. Now for the enigma. The 1700 is the Wh/kg energy content of gasoline, adjusted for the typical internal combustion engine’s 20 percent efficiency. The very best lithium-ion batteries can do at the moment is 400 Wh/kg and these don’t exist commercially yet. That means the practical electric airplane may be on the horizon, but it’s not around the corner.

I was really taken with your article on VGs in the June 2012 issue. I put them on my first Cessna 310 over 25 years ago. Checking them out, I feathered the right engine, put full power on the left and pulled into a steep climb. Pulled until the airplane stalled at about 5 knots slower than before. I still had positive aileron and rudder control. The stall was smooth, straight ahead. Next, restarted the right engine, let it warm up, shut down the left and repeated the process with the same results. I was really impressed and pleased with my decision to install them. Since then, I’ve been a real advocate and have even proposed that there be an AD to require them on all light twins. I still feel that way. I hope your article makes a believer out of more people. Could save a lot of lives.

A couple of years ago when I was having fun chasing down all the doublespeak larding up the avgas replacement effort, NATA President Jim Coyne made a comment to me as we were leaving yet another information-free meeting masquerading as a press conference. “You know,” he said, “you were born for this.” Jim is an old-school airplane guy from back in the days when the industry was a friendlier place than it is now and he’s a long-time aircraft owner and reader of Aviation Consumer. He knows me we’ll enough to sense my unrestrained glee in pursuing stories that certain interests in the industry would rather see kept in the shadows. This natural predilection springs from my experience as an unreconstructed hooligan in Catholic school and was further reinforced early in my career in the newspaper business, where wide-eyed awe is checked at the newsroom door.

Discretionary spending is one of the first casualties of tougher times, so we expected a drop in responses to our latest survey on interior shops. When you need a new engine, you pony up. But the airplane still flies with threadbare seats and cracked vinyl. You can tough it out. But this mineshaft canary survey surprised us. In 2008, we got 209 responses—not an overwhelming number, but enough to see some trends and make some solid recommendations. This time we got 132 responses. That’s a 37-percent drop, which is much more significant than we’ve seen on other surveys past to present. We also noticed a sharp rise in the number of do-it-yourself jobs. In 2008, six percent of the respondents bought kits from Airtex or reported some other DIY interior. This time, 10 percent had bought Airtex interiors, and that number climbs to 16 percent if you lump together those using Airtex kits with several folks who removed parts, brought them to a local auto upholstery shop and then reinstalled them.

When considering the viability of electric-powered aircraft, it’s important to note the huge difference between the internal combustion (IC) engine that burns hydrocarbon fuels and an electric motor that relies on a battery energy source. The ratio of air mass to fuel mass at efficient combustion (stoichiometry) is about 14.6. That is, for every pound of fuel burned, 14.6 pounds of air are consumed. But you don’t have to carry the air since it is available in the atmosphere. Fuel weighs about 6 pounds per gallon, so 16 gallons of fuel weigh about 100 pounds. Over 1400 pounds of air will be consumed in burning that amount of fuel. An electric motor requires that all of the energy be contained in the battery. Since the energy density of lithium batteries is about 26 times less than the energy of gasoline, there is nowhere for electric propulsion to go. It is interesting to note that gasoline has 10 times the energy density of TNT that needs to carry its oxidizer within.

Some of the most popular new LSAs are distinctly old-school in their roots. There are three popular modern takes on the Piper Cub. American Champion reintroduced the venerable Champ that begat the Citabrias and Decathlons. There are even a few modern Luscombes out there from an effort to revive that line.

After months of back-and-forth meetings with industry players, the FAA finally seems to have settled on an unleaded avgas transition plan that foresees an 11-year timeline and a strong central role for the FAA in testing and certifying fuels. The agency is also recommending the formation of another government/industry committee to oversee how an avgas replacement fuel—if one ever emerges—finds its way to the field.

When Garmin’s capable G600 retrofit PFD system came to market somewhere around 2008, it wasn’t the brisk seller many shops hoped for. Its sticker price closing in on $30,000 was part of the problem.

I think you have a typo in your article on the Diamond DA42 VI in the May 2012 issue in describing the performance of the current DA42 NG. In one part of the article, you said that the NG model at 8.3 gallons per side (about 90 percent power) could only do 167 knots. It was capable of speeds as high as 184 knots at 14,000 feet­—the highest altitude 90 percent power was available from the Austros in the NG.