by Lori Greenstein
"The fan is the most dangerous piece of equipment on the field," said the late Nikki Caplan to my ground school class. "Treat it with great respect."
Pilots all over the world don't. They take unnecessary chances with the equipment and their fan person.
The worst offense is tilting the fan, for any reason. There simply are no good reasons to do that to a fan. The world "tilt" is applicable to pinball, not an inflator fan.
According to Frank Hines, a pilot from St. Louis, Missouri, who has done extensive research on fans, tilting the fan is incredibly dangerous and hard on the equipment.
In the first place, tilting it backwards interferes with the gyroscopic plane of that highly tuned instrument. And when that happens, incredible strain is put on the crank shaft, which can lead to a broken crank shaft real quick. And that's not nice. That leads to propeller splinters flying everywhere.
When the fan is titled backward, think about where the blade is lined up in relation to the fan person's neck (maybe even the pilot's). Should the cage break apart, which is always a possibility, that prop could easily find its way to that very vital human body part.
Another risk is fire. As it tilts, there is a good possibility that gas will spill out and hit the hot spots. That's happened before, and should remind us to keep a fire extinguisher handy outside of the basket and near the fan.
On most fans, when tilted to the popular 45 degree angle most pilots request, the oil is draining away from the bearings which can also shorten the life of your inflator fan.
Mike Bien, my crew training instructor in St. Louis, has given a lot of thought to what is gained by tilting the fan. He maintains that an extra minute of cold inflation will pack the envelope full enough for a 15-30 second hot inflation with a steady burn to the overhead position. At most, tilting the fan to direct air as the envelope is coming up will only gain 5-10 seconds of extra air, if that much. He highly recommends that extra minute or two of cold inflation. It's much safer.
Another major mistake is to move the fan while at full speed. And it happens with frightening regularity. It is also incredibly dangerous. Again, moving it at all messes up the gyroscopic plane and puts a tremendous strain on the crank shaft, which can break. It happened at a St. Louis balloon race. Luckily, the propeller splinters didn't hit any bystanders.
Often pilots will ask that the fan be switched to the other side of the basket during cold inflation, or have it re-positioned for better air flow or if the basket is moving.
They seem to forget that a 24 inch propeller blade is moving at 255 mph on the outside edge at full speed, while a 30 inch blade is whirling at 360 mph at top RPM. Bien point out that, "You could wind up with a 12 inch prop instead of a 30 inch prop." It happened to a St. Louis pilot and that 12 inch prop is always shown at the annual safety seminar as a grisly reminder.
It's not quite so dangerous to move it sideways, away from the basket, as long as the movement is parallel to the blade position.
The safest and best way to move the fan is to shut it down to idle for a moment, then to full stop. Wait until the prop blade has stopped completely. It may take a moment or two away from inflation time, but it could save someone's neck.
Let's trace the best way to use the fan, beginning with step one, filling it up with gas before you leave for the launch field. It's a nasty surprise to find no gas when you're ready to crank it up.
Before you load it up, check the cage and make sure that the clips are in place and strong. You don't want the cage to blast apart during fan use.
During your off-season, Bien recommends that you check to make sure the prop is in time with the crank shaft. You can do this by looking to see where the blade stops after running. If it is in a vertical position, the blade and crank shaft are out of time. Fix it for smoother running. It's also a good thing to check from time to time during the flying season.
Repairs, like refinishing the blade and eliminating knicks in the blade must always be done by a professional prop expert. It is too easy to have an unbalanced blade if you try it yourself.
On to the launch field. The average fan weighs between 75 and 150 pounds. Unloading it from the chase vehicle should not be a one-man job. Again, the fan should not be tilted in transport. Oil can spill out, as can gas, and if you don't clean it up, you could easily wind up with oil blotches on your envelope. And oil degrades your fabric. Unload it in an upright position.
The fan should be placed behind the suede lip of the basket, a foot or so behind the basket edge (see Where, Oh Where, Does My Inflator Fan Go??). You don't want the blade lined up with the pilot's neck. Place it so that the exhaust is blowing away from the basket area. It should be placed no closer than five or six inches from the basket.
The inflator should always be manned, if at all possible. And, considering the cantankerous critter it can be, should not be the post you give a child to run.
The fan person should not allow spectators to line up parallel with the blade and should be familiar with the important parts of the fan. He/she should know where the on-off switch is, the choke, throttle and the spark plug.
The next step is to inspect the fan area for hazards. High grass in front of the fan can result in burning grass fragments making holes in your beautiful fabric. If there is high grass, "mow" it by pulling up the grass a couple of feet in front and around the fan. Or better yet, use a tarp. Remember, the fan creates tremendous low pressure, and we all know that low pressure sucks literally everything in its path.
Make sure that your fan person does not have long hair, drawstrings on the jacket, scarves or jewelry that could be sucked into the fan cage. That's happened too many times.
When placing the fan, position it so that the "slipstream" (air flow) is to the left of center. Most of the air flow spins off the right side of the fan. If properly located, the fan should create no "bad" side for your mouth crew except perhaps in the winter when that 45 mph airspeed makes things a bit nippy. To avoid mutiny by the crew, don't tell them what the wind chill factor will be standing on the fan side. Luckily, the worst of that is a couple of feet away from the fan.
During the winter, Bien and Hines both recommend that you pre-warm the fan by pointing it away from the envelope and letting it run on idle for three-four minutes. That will get everything working properly.
If you'reon any hard surface, like a parking lot, make sure the fan person holds it firmly in place. An unmanned fan can and will "walk" and you never know where it's going to go.
During your crew briefing, remind them to load the fan carefully, in an upright manner, and be sure to use bungee cords or something to secure it. Believe me, it's no fun to hear that "thunk" when the fan falls out of the back of the truck while turning a corner. That's another easy way to break a crank shaft.
Have your fan man move the prop blade to a horizontal position and store it that way when not in use. Moisture can create unbalance, which is another problem.
When everything is "go" crank up the fan and let it do it's job. Safely.
The inflator fan can be the balloonist's best friend, or his worst enemy. It's been a tremendous boon to ballooning. With proper care it blows up the balloon quickly and easily. It deserves attention and respect. And when that's given, you won't have to flap.