Philip Greenspun is posting about transitional training from his Diamond Star into a super-high-performance Piper Malibu. Here is one man living the geek dream, especially since he made his money from a company associated with Open Source software, the basis of street-credibility in the software world. I hope that he will post a lot more about the Malibu transition, so the rest of us can live the life vicariously.
(photograph courtesy Philip Greenspun)
[Update: once again, I missed a syndication URL] Pilots have been painfully slow to take to the blogsphere compared to people in other areas. We love our newsgroups, mailing lists, and web sites, but gosh-darn-it if we’re going to mess with them new-fangled blog thingeys. One of my ongoing goals for Land and Hold Short is to collect together links to other aviation weblogs, especially those that have something to set them apart, to start to build us from a bunch of fragmented sites into an online community.
I just stumbled upon an entertaining aviation weblog, Cockpit Conversation, which has three strong selling points:
It’s been 76 years since Amelia Earhart (the one who is pictured here) and 98 other pioneer woman pilots founded the Ninety-nines, but the face that aviation presents to the general public is still usually that of the pudgy, grey-haired middle-aged male (i.e. people who look like me). The reality inside aviation is different: go to many flight schools and you’ll see lots of women going through the professional pilot programs as well as sitting in the right seats as instructors, trying to survive their students’ bounce-and-go landings. It’s time we heard from a lot more from them, so that girls don’t end up thinking of flying only as an embarassing-old-dad kind of thing and shun it, either as a career or as a hobby.
I hope that the author finds a way to make an RSS or Atom feed available some time in the future. [Update: I missed it here]
Sometimes it’s hard to love the Canada Flight Supplement or its U.S. equivalent, the Airport and Facility Directory, printed on cheap, easy-to-rip newsprint in tiny smudged type, going out of date every seven weeks, and filled with abbreviations you have trouble remembering. Still, I was looking at the entry from Hearst, ON, where I’ll be flying for Hope Air next week (see this posting about my last trip), and I thought it might be interesting to see how the (very short) entry would look written out in proper English prose. First, a scan of the entry, with a link to a larger image:
Now, the same thing written out in proper English prose.
The Hearst airport is located at latitude 49 degrees 42 minutes 51 seconds north, longitude 83 degrees 41 minutes 10 seconds west, 1.5 nautical miles northwest of the town. The magnetic variation is nine degrees west, and the time zone is five hours behind UTC (four hours during daylight savings time). The elevation of the airfield is 827 feet above mean sea level. The airport appears in the AIR5008 Visual Navigation Chart (Thunder Bay), the E-18 World Aeronautical Chart, and the LO-4 low-altitude IFR enroute chart. It has at least one published instrument approach in the Canada Air Pilot.
The airport operator is the Corporation of the Town of Hearst, which can be reached by phone at (705) 362-4341. The airport can be reached directly at (705) 372-2842. The airport is certified by Transport Canada.
The airport has a terminal building with telephone and taxi services available. Food, medical facilities, accomodation, and car rental are available within five nautical miles of the airport.
NOTAMs for this airport are available in the NOTAM file CYHF. Flight planning services are available through the London Flight Information Centre at (866) WXBRIEF.
Services are available from 9:00 am to 5:00 pm local time (1400-2200z, 1300-2100z during daylight savings time) Monday to Friday. At other times, a callout charge may be levied for one or more services. 100 low lead avgas and Jet-A fuel are available, as well as all grades of engine oil. Airplane storage, services and minor repairs, long-term parking, airplane tie-downs, and airplane plug-ins are also available. The airport offers supplementary de-icing fluid and 1000/1500 amp jet starting units.
The airport has one runway surface, serving as runways 04 (magnetic heading 41 degrees) and 22 (magnetic heading 221 degrees). The surface is 4500 feet long, 100 feet wide, and paved with asphalt. Runway condition reports are available from the operator, and there is only limited winter maintenance.
Both runways 04 and 22 have flashing strobes serving as runway identification lights, together with green/red threshold and runway end lights and three-position, medium intensity edge lights. There is also PAPI approach path lighting at each end of the runway designed for an eye-to-wheel height of up to 10 feet. The pilot must key the microphone seven times within five seconds on the frequency 122.8 MHz to activate the runway lights. The pilot may then select the brightness by keying the microphone seven times for maximum brightness, five times for medium brightness, or three times for minimum brightness, also within five seconds.
The unmonitored aerodrome traffic frequency is 122.8 MHz. It is in effect for a five nautical mile radius up to 3800 feet above sea level.
The nearest navigation aid is the Hearst NDB, on the frequency 241 KHz broadcasting the Morse code identifier “HF”. It is a medium-power (50-2000 watt) transmitter located at latitude 49 degrees 40 minutes 2 seconds north, longitude 83 degrees 43 minutes 28 seconds west. From the NDB, the airport is 2.8 nautical miles on a magnetic track of 38 degrees.
Right-hand circuits are in effect for runway 22, in accordance with the Canadian Aviation Regulations, section 602.96.
There is a possibility of winter maintenance equipment on the runway outside of operational hours. There is also a possibility of wildlife on the runway. There is bird activity during the months of April to October.
That is a lot of information packed into a tiny space (and I left out the information printed on the diagram, including the safe altitudes around the airport). There is a certain ugly beauty about it. Now, if only I could remember all of those abbreviations …
Land and Hold Short has just moved from a hacked-up homemade system to WordPress, an excellent Open Source weblog manager. The new system has search, trackbacks, pingbacks, user comments, and many other features, so it should make reading the blog a lot more fun. I’ve done some .htaccess work to make sure that old permalinks keep working: please leave a comment if you find anything that’s not working or if you have any configuration suggestions. I’ll work on coming up with a custom theme later — just moving the old postings over was enough work for one Saturday afternoon. I’d also be grateful for category suggestions.
Note, too, that all old posts are (at the time of writing) commentless, because user comments were not possible until today.
I just received my January copy of the so-so IFR Refresher, and I came to an article “Choosing Wisely” about picking IFR alternates. IFR flying, I think, is 20% about flying and navigating the plane on instruments and 80% about memorizing obscure rules, and the IFR alternate airport rules (for choosing an alternative airport in advance, in case weather keeps you out of your destination) illustrate that point nicely. They also show some of the differences between flying in Canada and the US — I will admit to flying in the US without really knowing all of their alternate rules, and I’m sure that my fellow pilots from the US have done the same in Canada.
In Canada, if you file IFR, you have to file an alternate. Period. It doesn’t matter if every airport within 500 miles of your route is forecast to have blue skies and 50 mile visibility for the next week. In the US, sometimes you have to file an alternate and sometimes you don’t. In the US, a pilot can skip filing an IFR alternate if
But wait, that applies only if you’re a US Part 91 operator. If you’re a US Part 135 operator, the ceiling requirement is different: you have to add 1,500 feet to the lowest circling minimum altitude, or if none is available, to the lowest straight-in minimum altitude, then round up to at least 2,000 feet.
Is there any benefit to this extra complexity? The main problem with alternates is fuel: in both Canada and the US, you have to carry enough fuel IFR to fly to your destination, do a missed approach, fly to your alternate, do a missed approach, and then fly 45 minutes more. In a small plane with, say, a 600 nm range, you’re not going to be able to fly too far if your closest usable alternate is 200 nm from your destination. Not filing an alternate lets you file IFR and land with a smaller fuel reserve.
If the weather is bad, though, you may still need to pick a far-away alternate to get into a different weather system, so you’re back to the fuel problem. If the weather is good at your destination, then you can just pick an alternate airport nearby (my usual good-weather IFR alternate is Gatineau [CYND], a few minutes from my home airport, Ottawa/Macdonald-Cartier [CYOW]). In the end, then, I think this benefit is more imaginary than real. I’ll just stick with always including an alternate in my IFR flight plan, in Canada or the US.
There are many other finicky differences between the Canadian and US alternate rules, but those can wait for a future posting.
Sacramento Sky Ranch, which sells airplane parts, has an RSS 2.0 feed dedicated to light aircraft maintenance, including pictures and even sound.
There’s lots of great stuff here, from the sound a cracked cylinder makes when you flick the fin (yes, there’s a WAV file!) to why an oil/air separator to an engine is (in their opinion) an incredibly stupid idea. It’s aimed mainly at mechanics, but there’s good information for the owner/pilot as well. I’ve subscribed.
Student pilots and renters rarely worry much about the red knob or lever that controls the fuel/air mixture to their engines; owners worry about it a lot. For a while, there has been a big controversy about how far to lean engines: as the fuel/air mixture gets leaner (more air/less fuel), each cylinder’s exhaust gas temperature (EGT) gets higher and higher; then, if you keep leaning, the EGT drops again. The hottest possible exhaust temperature is called peak EGT. If you lean the mixture at peak EGT (i.e. reduce the fuel flow), the EGT drops and you are running lean of peak, or just LOP; if you enrich the mixture at peak EGT (i.e. increase the fuel flow), the EGT also drops and you are running rich of peak, or ROP. Which is better?
The LOP vs. ROP debate was pretty ferocious for a few years, but the LOP pilots seem to be gaining ground — after all, isn’t it better to cool your engine by burning more (free) air and less fuel, than by burning more fuel and less air? Besides, extra, unburned air doesn’t gunk up the engine, while extra, unburned fuel leaves all kinds of nasty stuff behind, as well as producing a significant amount of carbon monoxide (a big threat to winter fliers like me). Aside from the cost of fuel and the risk of CO poisoning, however, there’s also the question of engine health; after all, an early overhaul will cost a lot more than a bit of extra fuel.
The previous paragraph already mentioned gunk from flying ROP — for example, lead deposits that foul spark plugs — but the biggest threat to an engine is heat, not in the exhaust gas but in the cylinder itself. Many planes, including my Warrior, do not have a gauge installed for measuring cylinder head temperature (CHT), and most of those that do have a probe in only one of the four or six cylinders. The opponents of LOP (including some less-than-educated mechanics) used to claim that flying LOP increased cylinder temperatures and thus shortened cylinder life. In fact, it turns out that peak CHT — the hottest possible temperature inside the cylinder — actually occurs during ROP flight, specifically when the exhaust temperature has fallen about 25-50 degF on the rich side of peak EGT. In other words, if you lean your engine to peak EGT and then enrich slightly, you will be closer to peak CHT (and to damaging your engine); if you lean your engine to peak EGT and then lean a little further, you will be further from peak CHT. The chart that demonstrates this should be present in any engine operator’s manual (I’m using the one on page 3-13 of the Lycoming Operator’s manual for the O-320 and IO-320 series), but John Deakin also has one online here that shows the same thing (after you stare at it for 45 minutes or so; the best source of information on LOP operations, by the way, is John Deakin’s old columns on AvWeb — see engine-related columns in the sidebar).
So why not always fly LOP? One problem is that some engines just cannot do it. The fuel/air distribution to the cylinders is not always even, so one cylinder might be running much richer than another; by the time you lean far enough to get the richest cylinder LOP, the leanest cylinder might no longer have enough fuel to ignite at all, and the engine will start vibrating violently. Carbureted engines mix the fuel and air together in a single place (the carburetor) then send the mixture to all of the cylinders, where it arrives in various states (sometimes more air will get through, and sometimes more fuel). Fuel-injected engines actually mix the fuel and air separately for each cylinder, so it should be possible to adjust them so that all cylinders get exactly the same mixture.
In fact, the original factory injectors almost never work that well, but GAMI makes third-party injectors that do a much better job; not surprisingly, the company and its founder, George Braly, are strong advocates of flying LOP. Lycoming, one of the two major engine manufacturers, has just as strongly opposed LOP, using articles like this one. Essentially, Lycoming’s argument is that with a constant-speed propeller pilots have no way to read their power setting directly, so if they lean the mixture and increase manifold pressure to compensate for the lost power, they might end up flying lean at a dangerously high power setting. That argument does not apply to engines with fixed-pitch propellers, like the one on my Warrior, because there the power setting corresponds directly to the RPM at any given density altitude (or, in plain English, it’s no harder to figure out the power setting LOP than ROP). Even with a constant-speed propeller, the same horsepower should produce the same indicated airspeed no matter where the mixture is set, so it’s not that hard to manage the power setting.
The most fanatical faction of the LOP group — and the one to which I belong — is the group that flies lean of peak/wide-open throttle (LOP/WOT). Using this technique, you do not touch the throttle at all until you’re descending for landing; instead, you leave the throttle wide open the way it was for takeoff, and then you use the mixture (red button or lever) exclusively to control power, going leaner to reduce power, or richer to increase it. That way, you’re always flying the leanest possible for any given power setting (you cannot open the throttle any further to get more air), so there’s no hard brain-work involved. Of course, you need an engine that runs well LOP to pull this off, either a fuel-injected engine with GAMIjectors or a four-cylinder carbureted engine with good distribution like the O-320 (a six-cylinder carbureted engine is unlikely to work, because it’s impossible for all six cylinders to be the same distance from the carburetor). The fuel savings can be spectacular: I burn about 20% less fuel in my Warrior flying just as fast, and I have cleaner plugs and minimal risk of CO poisoning if the muffler ever leaks into my cabin heater. In fact, I am especially fortunate, because in the early 1980’s, Piper’s Warrior II POH actually recommended LOP/WOT far ahead of its time:
For Best Economy cruise, a simplified leaning procedure which consistently allows accurate achievement of best engine efficiency has been developed. Best Economy Cruise performance is obtained with the throttle fully open. To obtain a desired cruise power setting, set the throttle and mixture control full forward, taking care not to exceed the engine speed limitation, then begin leaning the mixture. The RPM will increase slightly but will then begin to decrease. Continue leaning until the desired cruise engine RPM is reached. This will provide best fuel economy and maximum miles per gallon for a given power setting. See following CAUTION when using this procedure.
CAUTION
Prolonged engine operation at powers above 75% with a leaned mixture can result in engine damage. While establishing Best Economy Cruise Mixture, below 6,000 feet, care must be taken not to remain in the range above 75% power more than 15 seconds while leaning. Above 6,000 feet the engine is incapable of generating more than 75%.
For my Warrior’s 160 hp O-320-D3G Lycoming engine, it seems to be RPM rather than power setting that determines things: my engine will almost always run smoothly LOP/WOT at 2500 RPM or above, and will sometimes let me get down to 2400 RPM. Obviously, then, I do better at higher density altitudes, where these RPMs give me safe power settings.
Despite all of the company’s opposition to GAMIjectors and LOP, at least someone at Lycoming seems sympathetic. The January 2005 issue of COPA Flight reprinted an article “Carburetor or fuel injection system?” from a past issue of the Lycoming Flyer newsletter (no date provided). Essentially, the article says that the advantages of a carburetor are cheap installation and maintainance as well as wider fuel lines that as less likely to plug up; the advantages of fuel injectors are no carb ice, the ability to fly inverted (for aerobatics), and improved fuel/air distribution, which
allows leaning that results in slightly lower overall fuel consumption. This is of particular value in higher horsepower engines where saving a small percentage of the fuel being burned may result in a significant dollar savings.
But wait … carbureted engines already have good enough distribution to fly a bit rich of peak. Is Lycoming suggesting that it’s possible lean further than that, perhaps to peak, or even lean of peak? I’m guessing that someone’s been brainwashed by GAMI’s marketing material. In the meantime, I’ll keep on flying little four-cylinder carbureted O-320 LOP/WOT until I find a good reason not to.
A comment by a fellow pilot got me thinking about headwinds and tailwinds. I started flying with serious misconceptions about how a headwind or tailwind affects a flight, and some of the bogus rules of thumb only makes things worse. I’m going to take a quick look at three popular misconceptions here — that you make up for a headwind on the return trip, that your average groundspeed over many trips is a good indication of your plane’s true airspeed, and that you should fly faster into a headwind to save fuel.
First, the easiest one. Let’s say that you’re flying on a round trip in a single day, and the wind is forecast to be the same all day. On your way outbound, you will have a headwind, and on your way back home, you will have a tailwind. Sounds about even, right? To try it out, consider a plane with a 120 kt true airspeed (like a Warrior or a Cessna 172) flying 300 nm each way:
| Wind Speed | Outbound | Inbound | Total |
|---|---|---|---|
| 0 kt | 2:30 | 2:30 | 5:00 |
| 20 kt | 3:00 | 2:09 | 5:09 |
| 40 kt | 3:45 | 1:53 | 5:38 |
In other words, you never make the time up, because you spend more of the flight in the headwind than the tailwind, by definition. There are tricks, of course, like flying low westbound to get a weaker headwind and flying high eastbound to get a stronger tailwind, but averaged over many flights, the best wind is still no wind at all.
And that comes to the second point. When people want to challenge the true airspeed figures put out by the airplane manufacturers, they often pull out their average groundspeeds, which are inevitably 10 knots slower or more, for which they usually blame the manufacturer’s marketing department. Part of the difference can be explained away by density altitude (nobody always flies at 7,000-8,000 feet density altitude), low power settings (many pilots are shy about setting 75% power), or climb, approach, etc., when the plane is flying outside its optimum conditions, but another big part of the difference is the wind. For example, in the table above, the plane’s average groundspeed would be 120 kt with no wind, 117 kt with a 20 kt wind, or 107 kt with a 40 kt wind. Average groundspeed is a more accurate indication of how long trips will take in a plane, but it is a different measurement than the plane’s true airspeed, because any wind at all hurts the average, and there’s almost always some wind.
Flying faster into a headwind will definitely get you home sooner, but it won’t usually save gas, despite what many pilots, including flight instructors and textbook writers, try to tell you. To demonstrate, I’ll use another table. At 8,000 ft density altitude, a Cessna 172p will fly 121 ktas burning 8.6 gph at 75% power, 112 ktas burning 7.4 gph at 65% power, and 100 ktas burning 6.2 gph at 55% power according to its POH; this table shows the time and fuel to fly 300 nm with different headwinds:
| Headwind | 55% power | 65% power | 75% power | |||
|---|---|---|---|---|---|---|
| Time | Fuel (gal) | Time | Fuel (gal) | Time | Fuel (gal) | |
| 0 kt | 3:00 | 18.6 | 2:41 | 19.8 | 2:29 | 21.3 |
| 10 kt | 3:20 | 20.7 | 2:56 | 21.8 | 2:42 | 23.2 |
| 20 kt | 3:45 | 23.3 | 3:16 | 24.1 | 2:58 | 25.5 |
| 30 kt | 4:17 | 26.6 | 3:40 | 27.1 | 3:18 | 28.4 |
| 40 kt | 5:00 | 31 | 4:10 | 30.8 | 3:42 | 31.9 |
| 50 kt | 6:00 | 37.2 | 4:50 | 35.8 | 4:14 | 36.3 |
| 60 kt | 7:30 | 46.5 | 5:46 | 42.7 | 4:55 | 42.3 |
Obviously, if you just want to get home, you are better off speeding up and paying for the small amount of extra gas–you’d have to be pretty dedicated to fuel savings to make your trip an hour longer to save 1.5 gallons of fuel. However, if you’re worried about running dry and there’s nowhere to turn around to (let’s say that you’re halfway between Greenland and Iceland), speeding up is not necessarily the best choice. Even at 55% power, you’re still burning half a gallon less gas than at 65% power and almost two gallons less than at 75% power flying directly into a 30 kt headwind. With a 40 kt headwind, speeding up to 65% power starts to make sense, but 75% will still burn a full gallon more fuel; in fact, you need to get up to a 60 kt direct headwind before you will save fuel by speeding up to 75% power.
Note that these numbers are for a very slow plane. If you’re flying a fast single, like a Lancair or Cirrus, or a twin, you will probably always be considerably better off at 55% for conserving fuel, unless you’re flying into a hurricane. I imagine that cross-ocean ferry pilots pretty-much always fly at low power settings, no matter what the wind is like.
Last week, I flew my first flight for Hope Air, a charity similar to Angel Flight in the United States and British Columbia. An icy, snow December is a strange time to start on something like that — many of the singles have been put to bed for the winter — but it was a nice, easy introductory baby trip from Ottawa to Toronto, and I had the benefit of knowing that Frank Eigler was waiting by his cell phone to charge to my rescue in his ice-certified Aztec if my little Warrior got stuck anywhere.
I’ve always wanted to help people with my time as well as money, but I had enough of stuffing envelopes during my teen years. Hope Air looked like a great opportunity, but only this year did I finally have enough hours to meet their requirements. They have a tough screening process, and I was happy to make it through and get my little baseball cap in the mail. The trip went well — I won’t print personal details about the patient or her escort, except that they were wonderful, friendly people — and I felt more like I was taking friends or neighbours for a ride than performing any act of charity. Frank was at the Toronto Island airport to meet me, and he gave me a city tour in his Aztec followed by some engine-out practice over Lake Ontario to celebrate my first Hope Air flight. I flew back late in the afternoon, and landed uneventfully despite a burned-out landing light (legal, as long as there are no passengers). My next flight will be to Kapuskasing in January, a much longer trip where the weather will have to be just right.
If you live in Canada, have the experience required, and are retired, self-employed (like me), or have an employer who is flexible about hours (like Frank, who works for RedHat), I highly recommend the Hope Air organization.
My Warrior is one of the slower planes on the apron. It’s not as slow as some people claim, of course — under ideal conditions, I actually can get within 2-3 knots of the 127 knots true airspeed promised by the POH — but it makes long work of short trips compared to (say) the Mooneys or Barons, not to mention the new Cirrus and Lancair planes. I thought it would be interesting to find out just how big that difference is in real life, and what the cost is, so I plugged the best performance numbers I could find for a bunch of light aircraft into a spreadsheet, and figured out cruise time and fuel for a 400 nautical mile trip with no wind, a 20 knot headwind (normal for a low-altitude westbound trip), and a 20 knot tailwind (normal for a low-altitude eastbound trip). The results follow.
As far as I can determine, these are all performance numbers for the plane’s optimal altitudes (depending on the engines). Unfortunately, I have not been able to find good numbers for the Lancair Columbia, so I’ve left it out: its performance should be similar to but slightly better than the SR-22. For a 400 nm trip, ignoring taxi, climb, and descent, here are the numbers:
| Aircraft | Speed (kt) | 400 nm time | 400 nm fuel (gal) | nm/gal |
|---|---|---|---|---|
| Beech Bonanza 35 | 160 | 2:30 | 35 | 11.4 |
| Beech Baron 55 (twin) | 188 | 2:08 | 58 | 6.9 |
| Cessna 172M | 120 | 3:20 | 27 | 15.0 |
| Cessna 182 | 140 | 2:52 | 39 | 10.4 |
| Cirrus SR-22 | 180 | 2:13 | 36 | 11.0 |
| Diamond Star | 147 | 2:43 | 25 | 16.2 |
| Diamond TwinStar (twin) | 181 | 2:13 | 24 | 16.9 |
| Mooney 201 | 160 | 2:30 | 26 | 15.2 |
| Piper Warrior II | 127 | 3:09 | 27 | 14.9 |
| Piper Arrow | 137 | 2:55 | 31 | 13.1 |
| Piper Seneca (twin) | 197 | 2:02 | 59 | 6.8 |
Some of the slower planes are surprisingly fuel efficient in this table: for example, the Cessna 172 and the Piper Warrior are almost as fuel-efficient as the Mooney 201, though they take a fair bit longer to complete the trip. The range of fuel efficiency is quite large: from 6.8 nm/gal for the Seneca, to 16.9 nm/gal for the TwinStar.
A headwind should improve the relative fuel efficiency of the faster planes, since they spend less time in it than the slower ones. It will also greatly increase the time spread between the fastest and slowest planes:
| Aircraft | Speed (kt) | 400 nm time | 400 nm fuel (gal) | nm/gal |
|---|---|---|---|---|
| Beech Bonanza 35 | 140 | 2:52 | 40 | 10.0 |
| Beech Baron 55 (twin) | 168 | 2:23 | 65 | 6.2 |
| Cessna 172M | 100 | 4:00 | 32 | 12.5 |
| Cessna 182 | 120 | 3:20 | 45 | 8.9 |
| Cirrus SR-22 | 160 | 2:30 | 41 | 9.8 |
| Diamond Star | 127 | 3:09 | 29 | 14.0 |
| Diamond TwinStar (twin) | 161 | 2:29 | 27 | 15.1 |
| Mooney 201 | 140 | 2:52 | 30 | 13.3 |
| Piper Warrior II | 107 | 3:45 | 32 | 12.6 |
| Piper Arrow | 117 | 3:25 | 36 | 11.4 |
| Piper Seneca (twin) | 177 | 2:16 | 66 | 6.1 |
At this point, the slower planes (including the Cessna 182) really start to suffer. With 40 gallon tanks, the Cessna 172M is pretty-much at the limits of its fuel reserves for this trip; the Warrior, with its 48 gallon tanks is still safe (probably even for IFR), but both make for a very long trip. The Seneca is now almost twice as fast as the Cessna 172 and Warrior. Note, though, that the Baron still has only a half hour advantage over the Mooney, while burning more than double the fuel.
A tailwind should eliminate some of the advantage of the faster planes: they will burn more fuel, but won’t get you there all that sooner:
| Aircraft | Speed (kt) | 400 nm time | 400 nm fuel (gal) | nm/gal |
|---|---|---|---|---|
| Beech Bonanza 35 | 180 | 2:13 | 31 | 12.9 |
| Beech Baron 55 (twin) | 208 | 1:55 | 53 | 7.6 |
| Cessna 172M | 140 | 2:52 | 23 | 17.5 |
| Cessna 182 | 160 | 2:30 | 34 | 11.9 |
| Cirrus SR-22 | 200 | 2:00 | 33 | 12.2 |
| Diamond Star | 167 | 2:24 | 22 | 18.4 |
| Diamond TwinStar (twin) | 201 | 1:59 | 22 | 18.4 |
| Mooney 201 | 180 | 2:13 | 23 | 17.1 |
| Piper Warrior II | 147 | 2:43 | 23 | 17.3 |
| Piper Arrow | 157 | 2:33 | 27 | 15.0 |
| Piper Seneca (twin) | 217 | 1:50 | 54 | 7.5 |
All of these numbers are a little misleading, of course. For example, the first part of any trip is spent climbing, and a plane that climbs slowly (like the 172M or the Warrior) will spend relatively longer than a plane that climbs fast (like the twins), slowing it down a bit. There’s also the matter of maneuvering around weather enroute, long vectors for approaches at the destination, and so on. All of these planes, then, will take a little longer for the trip than these numbers suggest — my Warrior, for example, more typically needs 4:00 takeoff to landing for a 400 nm westbound trip with a moderate headwind, and 3:00 for a 400 nm eastbound trip when you factor all of that in.
The twins are not much faster than the high-performance singles but burn a lot more gas. Of course, they have other benefits, such as a redundant engine and (often) deicing equipment, but those come at a very high price. The one exception is the TwinStar, which actually outperforms its single-engine sibling both on speed and fuel burn.
So, in practical terms, what would it mean to me to upgrade to a faster plane, like a Mooney 201 or even a Cirrus? On this hypothetical 400 nm round trip with a headwind outbound and a tailwind inbound, my Warrior uses 6:38 flying time and burns 55 gallons of AvGas (about USD 190.00 at current fuel prices). A Mooney 201 would use 5:03 flying time and burn 53 gallons: that’s a hour and a half faster and about USD 10.00 less fuel to boot. A Cirrus SR-22 would get me there and back in only 4:30, for a two-hour saving, but would burn 74 gallons, adding about USD 90.00 to the fuel cost. In other words, the Cirrus saves only a half hour over the Mooney at a cost of USD 100 extra in fuel. Most of the twins are too expensive to even bother calculating, except for the TwinStar, which manages the trip in the same time as the Cirrus using even less fuel than the Mooney.
Land and Hold Short 
