Last time out I talked about figuring how far you could fly on a tank of fuel. Assuming you have that well-in-hand, its time to talk about planning and executing a trip. I'll use a case-study based on a 42 mile jaunt up to Ionia, Michigan - the state's soaring capitol - that Don and I made last August. The flight was a memorable one that would take us up to the northwest over areas where we had not previously flown - for reasons that will become obvious shortly!
PLANNING
The first stage of flight planning involves getting out your trusty aeronautical chart. We could have used the Detroit Sectional, but we are fortunate that the Michigan Aeronautics Commission publishes a fine state chart each year. It contains all the information on the FAA sectional but has the advantage of showing more detail. Figure 1 is a much-simplified version of the picture provided by the charts. The aeronautical chart provides the location of all the various airports in the area we would be flying.
The filled-in circles on Figure 1 are the municipal and county airports with paved runways. The open circles are private sod fields. A direct flight to Ionia would run just about 40 miles - a distance that ranges from easy with a tailwind, tight with no wind, and impossible with any head-wind component. Prudent flight planning would involve identifying an intermediate field if winds proved unfavorable. The municipal airport at Grand Ledge - essentially the half-way point - was the designated intermediate. The other fields are factored in, just to hedge our bets in case of unforeseen problems.
The chart also provides essential airspace data, in this case, the two circles denoting the limits of the Class E airspace around Capitol City Airport at Lansing. As an ultralight, assuming we watch out altitude, we can fly under the outer circle, but the inner circle requires prior clearance from the Lansing tower. We had no intention of getting that close, but a glance at the direct bearing from Bergeon to Grand Ledge shows how close we could come. If you don't know where the limits of controled airspace are, you can't be sure of staying out! Just for the record, our metal blades provide a distinctive radar signature and the Lansing controllers watch us every time we fly. If we were to have a "slight" navigational error, they know who's door to knock on! Although, with careful altitude control, we could pass through going directly to Grand Ledge or Ionia, there are other problems with the direct routes that I will get to shortly.
Although the charts provide essential information on the fields shown in Figure 1, it is always nice to know more. My desk has a copy of AOPA's "Airports USA" as well as the Michigan Aeronautics Commission's "Michigan Aiprport Guide". Either of these publications helps to round out the information on each field - flight activity, detailed layout of runways, obstacles, and other useful tidbits, including phone numbers in case things don't work out exactly as planned. Grand Ledge, for example, has an Army National Guard helicopter unit. They are always doing low-level training and the Army has gone out of its way to make the aircraft hard to see. That's the kind of information you need before you get there!
The final element in our flight planning arsenal is the DeLorme book of county maps for the state. These maps allow you to integrate major highway routes with the information from the aeronautical charts. The highways themselves are useful navigation aides, as are interchanges, rest stops, and weigh stations. The other thing the county maps can provide is a realistic layout for built-up areas, which are off limits to ultralight flying. These areas are noted with cross-hatching in Figure 1 - the city of Grand Ledge itself is off-limits, as is the area coming southwest out of Lansing, due to extensive development along the I-69 corridor. It's those areas that make a direct route to Grand Ledge or Ionia highly impactical (the dashed lines), leading to the solid-route lines designed to avoid all that mess.
The county maps and charts can both provide information on other essential landmarks, such as the radio tower complex located just inside the Class E outer perimeter on the southwest side of Lansing. All this may sound like a lot of hassle, but I get a kick out of planning a flight when I can't actually be flying. In this age of $200 hand-held GPS units, there is still no substitute for old-fashioned pilotage. There is nothing like a GPS if you get lost, but if you take the time to do your flight planning in advance, you won't get lost!
DOING IT!
All of this homework was done in conjunction with planning for a flight up to Greenville, Michigan to attend the Michigan Gyro Fly-In scheduled for the 19th and 20th of August. We planned to fly up on Sunday (the 20th), stopping at Ionia and then making a short run (about 20 miles) on to Greenville. We planned on a long stop-over at Ionia on the return leg because a week-long soaring contest was starting that weekend and Don (a sailplane pilot) and I had many friends who would be there.
Fog and rain early Sunday morning resulted in our making the trip to Greenville by car, but we vowed to try to get to Ionia by air sometime during the contest, if only to show off the Gyrobee. The next day, Monday, was marvelously clear but there was a steady 25 mph wind from the northwest. Don called me at work and said he was going to give it a shot and that I should run by the field and pick up the gas cans. He was already at the field and would head off for Grand Ledge, where, if all went well, I would arrive with an ample supply of premix!
The thermal activity was one step short of awesome and the wind cut his ground speed to a sedate 25 mph, but he perservered, going around the airspace boundary southwest of Lansing and then threading the needle under the restricted zone and around Grand Ledge to arrive only a little the worse for wear! The advanced planning had already paid off, for it was obvious that he wouldn't have made it if he tried to fly direct! Our rendevous at Grand Ledge went off without a hitch and, freshly topped off, Don departed on the second leg. This time we had an even start and I got to Ionia well ahead, even though the wind was sufficient to knock the van around a bit. Don arrived at Ionia just as the last sailplanes were returning from the day's task and held off until they touched down.
All-in-all, he had flown for over one and a half hours to travel just 42 miles. Conditions were hardly ideal, but they would have been impossible for a fixed-wing ultralight and even the Piper and Cessna drivers were waiting for things to calm down! Quite a few of the sailplane pilots, some of the best in the country, had landed out because the wind just made it too difficult to make optimum use of the thermals.
If there was ever a day to highlight the practicality of an ultralight gyro, this was it! We had a marvelous visit with old friends, most of who thought we were certifiable.
By about 6:30 it was time for me to fly the Gyrobee back home. The cumulus cloud streets were dissipating, promising a smoother ride, but the wind was still blowing hard from the northwest, but this time it would be a tailwind, promising a non-stop trip. Figure 2 shows three channels (fuel, airpspeed, and altitude) of Digipod flight log data for the return flight. One way or another, these three curves represent a few very practical pointers for cross-country flying, especially if you're doing it under Part 103.
The first lesson concerns takeoff and your climb-out to cruise altitude. First, your rotation and initial climb-out should always be made at full-throttle for three very practical reasons. First, you want to initially gain altitude as quickly as possible. An obvious reason is to safely clear any obstacles around the airport perimeter, but it is even more important in terms of buying you options. The faster you climb, the higher you will be when you cross the runway threshold, irrespective of where you lifted off. If you run out of runway at one or two hundred feet and then have a problem, your options are pretty much limited to putting down straight ahead. You won't be able to get back to the runway and the only thing worse than having to land off-field into the wind (read SLOWLY), is to put down in the brush crabbing into a cross-wind or, worse yet, going like a bat downwind!
Replay that same scenario with 500 feet or more under your keel and you can easily do a 180 and have the entire runway available for a proper downwind landing (watch the AIRSPEED, not your groundspeed!). You might even have time for a 360 into an upwind landing, but remember that old adage about a "bird in the hand"! The second reason is that you will get off the ground faster, giving you more runway to play with, which takes us back to point #1. Finally, if the engine is going to give you problems, it will most-likely do so when called upon to deliver sustained full-throttle.
If the engine is going to be tempermental, I would prefer to know while still over the runway and not out in the bush! I can't resist a little aside at this point. I have lost track of the number of times folks have implied how nerve-wracking it must be to fly a gyro with ONLY a 40 horse engine! If the Gyrobee has a disc-loading of 1.3 to 1.5 psf, like most single-seat Experimental machines, it would indeed be a very marginal machine with the 447. In fact, its disc loading is only about 0.9 psf and that makes all the difference in the world! Note that the initial rate of climb up through 200 feet is almost 700 fpm - at an average airspeed of 25 mph! At its best-rate-of-climb airspeed (35 mph) it tops out near 1000 fpm on a typical summer day and it WILL hold altitude at under 10 mph!
The trouble is, you can't keep the full-throttle business up very long if you intend to fly any real distance on your measly five gallons. If you look at the fuel graph for the first 45 seconds of so, you will see the problem. Sustained full-throttle will rapidly gobble up fuel you need for range.
Whenever I have a long way to fly, there is a simple trick I use that will get you to cruising altitude with minimal fuel consumption. If you look at the fuel consumption curve, you will see a sharp break at about 45 seconds into the flight, where the fuel draw drops sharply and holds a constant value for the rest of the flight. This break, which occurs at a little over 200 feet in altitude, represents the point where I cut the throttle back to its cruise setting (approximately 5100 rpm). This might seem to violate the cautions I gave you previously, but it doesn't, given the conditions that day. I lifted off into a 25 mph headwind and, by the time I was at 100 feet or so, I was virtually stationary over the middle of the runway and climbing!
So how do you keep climbing at cruise throttle? The answer is by playing with your airspeed. The Gyrobee will hold altitude at 5100 rpm at an airspeed of a little over 50 mph. If you fly any faster, without increasing throttle, you will descend! But you also have to remember that the aircraft's best rate-of-climb airspeed is 35 mph. With 5100 rpm and 35 mph airspeed, the Gyrobee climbs at a couple of hundred feet per minute and I am still flying down the rest of the runway at a groundspeed of only 10 mph! By the end of minute three of the flight I am over 500 feet high and still over the runway! At that point I turn downwind and head for home! As I gradually approach my target cruise altitude I am slowly increasing the airspeed and thus reducing my rate of climb until I reach essentially level flight at about 50 mph! The Gyrobee is rigged so she cannot fly faster than 63 mph and maintain level flight (the aircraft really IS Part 103-legal!), but, because it is designed for optimum performance within its speed range, it ends up being very versatile in terms of the games you can play within the laws of Physics!
Throughout most of the flight you will notice small variations in both airspeed an altitude. These are an inevitable consequence of wind gusts and residual thermal activity and are to be expected. In the middle of the day they can be really quite impressive! It is just this sort of up and down in both airspeed and altitude that can lead a low-time pilot to try to correct, often with unfortunate consequences in terms of PIO and bunt-overs! If you have enough time under your belt to have confidence in your aircraft, you will just ride it out and stay out of trouble! If you are tooling along at 1000 feet, the up and down roller-coaster is hardly noticeable (you will still see the airspeed variations) and you won't be tempted to over-react. Put a low-timer at a couple of hundred feet and the chances are very good that they will panic and start to develop a pitch control problem! That's why you should stay away from wind and thermals until you have plenty of flight time, especially if you insist on flying around at low altitude!
This particular flight record also shows another phenomenon that can catch a novice by surprise. Look at how the altitude variations increase in the latter half of the flight, reflecting an increase in thermal activity. So if I left around 6:30 when thermal activity was declining, why does it get bumpy around 7:00? The answer is simple, but not particularly obvious. On a clear day, as the sun gets lower in the sky, the air will cool faster than the ground. Masses of air at ground level, which were not warm enough (in relative terms) to break loose and rise earlier, will do so as the air cools down, leading to a very bumpy ride (with NO cumulus indicators), just before things really do calm down. The take-home lesson here is simple. If you are unsure about your ability to handle thermal turbulence, hold off just a bit longer in the early evening, just to make doubly sure the air will be as smooth as you expect. The differential cooling of air and land surface also leads to an increase in the wind just before it really starts to taper off. At about 33 minutes into the flight I had arrive back at Bergeon field and was starting my descent as I made a standard pattern entry.
Normally I would fly the pattern at close to cruise speed, but as I turned on base, my groundspeed dropped to almost zero due to a combination of a change in wind direction and an increase in wind speed. Since I was descending, I could punch the airspeed up to 65 or so without the need for throttle and I had to do so if I was going to make any progress against the wind. The higher airspeed also made it easier to handle both the wind gradient as I got lower, not to mention that the wind was now quartering across the runway (which is oriented WSW-ENE). If you want an indication of the sensitivity of the Digipod flight recorder, look at where the steep rate of descent stops for a few seconds at 35 minutes. I was approaching the field quite slowly, even at 65 mph, because of the wind and I estimated that I was going to be just a tad short of where I wanted to touch down. The little "blip" in the steady descent trace is where I applied throttle for a few seconds, arresting my descent to stretch the approach!
Now for one final parting shot at the nay-sayers. One of the bits of wisdom that you will hear is that unltralight gyros can't handle wind and turbulence as well as the heavier machines, especially if the disc loading is kept low to get performance. So maybe I've been laying it on a bit about the wind! Fact is, by quoting surface wind conditions, I have actually been significantly under-estimating the winds aloft, as the Digipod flight record will demonstrate. The Gyrobee left the pattern at Ionia at about the three minute mark in the flight and arrived at Bergeon field at the 33 minute mark - about 30 minutes point to point. The flight path was 42 miles so the average ground speed was 84 mph! The average airspeed for the 3-33 minute portion of the flight was 52 mph, so the tail-wind component was 32 mph (84-52)!
By the way, something the graphs and data can't show - the flight was fantastic! That's why we fly cross-country instead of orbiting the airport!
Figure 1. A diagram showing the main flight planning factors for the jaunt from Mason to Ionia and back. The round, filled-in circles are county and municipal airports with paved runways. The open circles are private, sod fields. The two concentric circles define the limits of Class E airspace around Lansing's Capitol City Airport. The cross-hatched zones are built-up areas that are off limits to Part 103 operations. The dashed lines represent the straight-line flight paths between Mason and Grand Ledge and Mason and Ionia, both of which are off limits due to restrictions in Part 103 flight operations. The solid lines represent the shortest legal routes with actual flight paths being somewhat longer to provide a margin of error.
Figure 2. Three channels of data (airspeed, altitude, and fuel consumption) for the Ionia to Mason return flight. This kind of information provides a wealth of data on aircraft performance as well as illustrating some techniques, discussed in the text, for stretching your cross-country excursions within the limits of the Part 103 regulations.
Photo - The Gyrobee sits in lonely splendor on the apron at Brooks Field in Marshall, Michigan, about 35 miles from home. Despite the range limitations of the 5 gallons permitted by the ultralight regulations, Don and Ralph prefer to arrive by air!