Flying in the wind (Part 1 of 2)
Other than potential encounters with powerlines, flying in windy conditions has always been considered one of the major nemeses of balloonists. This is because it difficult to make an immediate halt with a 2 ton mass in 3 knots, let alone 10-20 knots. Since immediate stops are not possible (with the exception of smacking an obstacle), the deceleration process is the most critical during the landing phase and where most of the injuries occur.
As a pilot gains experience, he/she discovers that all “high wind” is not alike. The types of “high wind” range from gust fronts from a thunderstorm to wind created by a pressure gradient. A pressure gradient is wind driven towards a low in one direction from a high in another direction. These winds are often laminar (smooth, little friction interference) in flow are suitable for flying for capable pilots.
Our discussion here will center around flying in winds that are laminar in flow and not generated by local storms or late morning convective activity. Another exception is flying windy conditions in the mountains. Even if the winds appear to be smooth and gradient driven, mountain turbulence will certainly accompany any significant winds blowing through and across the mountains.
The first question to ask when considering a windy flight is “Are you prepared to land in the current wind plus 5-10 mph?” Is there ample room downwind for some dragging? In areas compatible with evening flights, it is probably still wise to be capable of executing a landing at somewhere near the speed you took off because it doesn’t always slow down.
The components of a planned high wind flight are the same as a calm flight other than their execution. High wind takeoffs can be quite a damaging affaire for a balloon if not executed properly. I will describe my method below. It may not be the only way but it has served me well with no fabric burns in memory and smooth takeoffs,
If it even feels like the wind is going to pick up during inflation, plan on a high wind takeoff. The first order of business is the tieoff. I use a 10’-20’ rope tied to a structural part of my vehicle (not under a bumper or cutting point). At the end of the rope, I have a figure 8 repelling device. At the basket, I have a bridle from the top of one upright to the other making a “V”. I slip the “eye splice” of another 10’ rope on to the bridal. The end of this 10’ rope will feed through the figure 8 and back to the basket and be temporarily tied off for me to control the liftoff. Quick release tieoffs seem to work as well. However, I find my system, while a little more complicated allows, for more finesse and timing at takeoff, minimizing those “Shuttle Launch” blast offs.
Always preload the basket with everything you will need for the flight except the passengers. Crew should be given special chasing instructions if necessary before the fan is started. Passengers should be briefed specifically on how to get in the basket the moment they are instructed. They should be told to be near to the basket (in a safe location) at all times and ready to get onboard at the moment of vertical inflation unless otherwise instructed. Remind them to get any forgotten personal items, or perform other necessary functions before this process starts.
The cold air inflation process is simply a task of managing the balloon. Depending on the windspeed, the balloon will roll left and right anywhere from 10 degrees each way to as much as 45 degrees. Rock and roll approaching 45 degrees needs to be dampened by the crown person(s). Sometimes, the most effective method of dampening this severe level of roll is for the crown team to move out 90 degrees from the top of the crown and stabilize the balloon when it rolls back to alignment with the basket then hurry back for more support along the windline. The crown team’s main task is minimizing the left to right roll of the envelope. Under normal high wind situations this is best accomplished by either pulling tight down the windline or running 20 degrees to the opposite side of the roll and dampening the roll and then running back to the other side and repeating the process.
I have found that the crown team has little to do with the vertical control of the balloon during the hot air inflation in wind. Certainly, they help keep the envelope aligned with the basket and manage to keep the balloon at ground level a little longer but the wind does the majority of the work keeping the balloon down. For this reason, it is very important to instruct the crew to “feel” the pull of the balloon when approaching 45 degrees to vertical and release down pressure if the balloon stays there naturally. If the crew continues to pull, the buildup of radiant heat in the throat, coupled with proximity of the hottest part of the flame near the upper part of the mouth often results in the instantaneous disappearance of fabric.
Once the crown line develops a little slack, that’s a sure sign that the crown team is not needed to hold the cap down any longer. If there is ample crew, the pilot might want the crown line person(s) to help maintain some stability from out there to minimize bobbing and weaving while passengers are loading. If the pilot has preloaded everything needed for the flight, the passengers should be just about loaded by the time the crown person delivers the crown line end to the basket. At this point, the balloon should be allowed to go to the end of the tie off (if not already there) and the crew used for weigh off should start letting go one by one as instructed by the pilot. As the pilot nears the suspected liftoff temperature, there should be only one crew left hanging on for ballast. I know this sounds strange, but as a pilot, I find it difficult to sense how much lift I have when 3 or more crew people are holding me down with their full mass. If you have a good tie down system, one knowledgeable crew person can control the basket until just before liftoff. At the appropriate moment the pilot must sense his/her actual lift (adjusting for false lift), instruct the crew to release the basket, and slowly release the tie off when the balloon is poised for a smooth takeoff. If executed correctly, the balloon will ease off the ground, allowing the pilot to compensate for any unexpected false lift, and continue to the desired altitude in full control with little if any distortion.
Next issue: Flying and landing in High Wind