Comments on: Chasing efficiency

By: Mike Perkins

Mike Perkins — Thu, 19 Jun 2008 19:00:09 +0000

The easy answer with aircraft we own right now, today, is to fly at a reduced power setting. A simple Excel spreadsheet reveals that:

A 1965 C-172 can get either 15.1 or 17.8 mpg at 75% or 44% power respectively (no wind). That’s an immediate savings of 18%.
A 1980 C-152 can either get 16.9 or 21.1 mpg at 75% or 46% power respectively (no wind). That’s an immediate savings of 25%.

The same spreadsheet shows that with a 40mph headwind, fuel savings is still obtained by throttling back. Same airplanes in a 40mph headwind:

C-172 gets 15.3 or 16.1 mpg at 75% or 44% respectively
C-152 gets 8.3 or 8.5 mpg at 75% or 46% respectively

Obviously the immediate answer is to Throttle Back. This isn’t theoretical or a future concept. This is right now, today.

By: Bob Wilson

Bob Wilson — Wed, 18 Jun 2008 03:50:06 +0000

If you want to know about fuel effeciency, they just had a fuel effeciency race near Colorado Springs last week. Rob Martinson flew his 0200 variez at about 135 mph and 2 gph for a 66 mpg flight. Gary Hertzler the other fuel effeciency gurue made 61 mpg. Robs e-mail is N

By: Chris OCallaghan

Chris OCallaghan — Tue, 17 Jun 2008 21:13:20 +0000

My Schempp Hirth Ventus 2bx has a glide ratio of about 45:1 at 60 knots and around 30:1 at 90 knots. Last Sunday, I took an aerotow to 1500 feet agl, releasing into a thermal that lifted me to 5500 agl. The 265 hp Pawnee burned about 2 gallons during its 7-minute flight. I was in the air for 4h26m. About an hour was local soaring. The rest was a 210-mile cross-country flight at an average speed of 60.9 mph. Hardly fast, but great for sight seeing and decidedly satisfying.

The numbers:

Total flight time: 4h33m (glider and tow plane/two take-offs, two landings)
Fuel used: 2 gallons of 100LL
Cost of fuel: $12
My total cost: $22.50
Burn rate: 0.44 gallons per hour
Efficiency: 105 sm per gallon
Fun factor: Off the scale

There are lots of choices available. If stick time is your goal, a glider is among the most cost-effective alternatives. Inside the cockpit it’s simple. It’s outside that’s complex. Of course, touch and goes are a challenge. Everything has trade-offs.

Oscar Charlie

By: John Drago

John Drago — Mon, 16 Jun 2008 13:45:50 +0000

My Bonanza burned more fuel than I was willing to buy and I only had 2 passangers in the back seat in a 3 year period. My Cessna 140 was fun but a distant mission was shall I say time consuming. The answer is a IO 360 Cont. pawered Swift. I lean to 9.2 gal at 6k and go 150mph indicated.

By: Ian Twombly

Ian Twombly — Mon, 16 Jun 2008 13:03:33 +0000

Great comments. The range of opinions in this string are about the same as in our office conversation. Good stuff.

Dr. Rogers – thanks for chiming with a little more of the technical side. Interesting.

George – Motor glider. A segment I hadn’t considered. With prices that match the LSA scale, they seem like a good option. Wonder why we aren’t seeing more…

Vince – Good point about seeking out cheaper fuel, although I’ll put in a shameless plug for AOPA fuel prices http://www.aopa.org/members/airports/. Sorry I looked. FDK is up to $6.32/gallon. I wonder how much people are actually flying out of the way in search of cheaper fuel. Sounds like a subject for another blog.

By: Paul Hamilton

Paul Hamilton — Sun, 15 Jun 2008 20:51:37 +0000

I just finished a 2 hour flight for “fun” and burned 7 gallons of auto gas in my Light-Sport Aircraft(LSA). If you want to fly just for fun with the wind in your face consider a LSA trike. It is the difference between driving in a car and riding a mototcycle.

If you want to stay with an airplane, consider the top of the line airplane LSA burning about 4 gallons per hour of autogas at 100 knots or 5 GPH at 120 knots. Modern technology LSA are about half the weight, more streamlined, and have more efficient propulsion systems than older designs.

By: Vince Kreizinger

Vince Kreizinger — Sun, 15 Jun 2008 16:49:16 +0000

While everyone is attempting to increase their fuel economy by running their engines at a lower power percentage setting and running LOP, (I do both of those) I don’t see anyone talking about AirNav. I just flew my Cardinal RG from San Diego to Toledo, OH and bought fuel near Kansas City for $3.80. So while you can do the other stuff, don’t forget to buy your fuel where it makes the most sense. Saving a buck a gallon by flying to an airport near your flight path just makes sense.

By: Symphony Pilot

Symphony Pilot — Sat, 14 Jun 2008 04:47:37 +0000

I am very happy with the gas mileage on my 2002 OMF Symphony Aircraft. With a Power Flow exhaust and Blue Printed Performance Engine, I am getting 6.5 GPH at 100 kts, which is almost 18 miles per gallon. Sure my Harley gets better mileage, but not having to deal with interstate traffic between Wisconsin and Illinois makes it all worthwhile.

Donovan Moore
Spring Green, WI
breakupexxonmobil.com

By: Glen Ramsey

Glen Ramsey — Sat, 14 Jun 2008 02:33:06 +0000

Don’t know if your interested in RV’s I regularly get 5.8 GPH on my 2000 RV8 with a Lycoming 0-360 carburetor mags, and constant speed prop. 2250 RPM 22″hg 1400 deg ext. 140 kt @ 2000′ 160 kt @ 8000′.

By: Steve Ells

Steve Ells — Fri, 13 Jun 2008 23:13:13 +0000

My stock 1960 Piper Comanche burns 10 gph and cruises at 132 knots, or 151 mph. I am planning to install flap and aileron gap seals, and check it again. Not bad for a 48 year old airplane.