Ralph E. Taggart

Rotorcraft Magazine, February/March 1993

Back in November of 1990, Chapter 63 (the Central Michigan Gyroplane Club) had a program entitled "Winterizing Your Gyro." I don't remember who the speaker was, but it was an excellent treatment of all the things you had to consider in buttoning your machine up for winter. When the formal talk was over, he asked for any suggestions he might have missed. Don Chubb and I had been setting up the VCR for a video presentation on our ultralight Gyrobee while the speaker was holding forth. When he opened the floor for comments, I chimed in with something to the effect "Why not fly the thing and save all the extra hassle?". There was a moment of silencer already had a reputation for making off-the-wall comments and then everybody had a good laugh and the give-and-take picked up again.

While everyone thought the comment was funny, both Don and I are quite serious about the business of winter flying. Back in 1981, when we first started flying our Quicksilver fixed-wing, winter weather seemed to arrive all too quickly and we were reluctant to stop flying just at the point when we were starting to get a bit of proficiency. Eipper Aircraft had just come out with snow skis for their aircraft, so we picked up a set and started logging winter hours and some fantastic flying! Eventually I wrote an article on ski flying for the long-defunct (Ultralight Aircraft magazine and did a chapter on the same subject in Markowski's book, Ultralight Techniques. When we made the decision to build and fly the Gyrobee, we weren't about to kiss off half the year just because it was a bit chilly!

Winter means a wide range of possible conditions, depending upon where you live. You Sun Belt types tend to treat a day in the 40s as the end of the world, while we Snow Belt natives would think it was a heat wave! Most of us in the northern tier of states (not to mention our neighbors to the north in Canada) get to contend with some pretty nasty winter conditions, but there are still sunny days (even in Michigan!) where the temperature will range from zero up to the freezing point. With a little thought and planning, those can be superb flying days.

I won't pretend that you can get in as much flying as you would in the summer, but that is mostly a result of the fact that the short days mean you can't get out and take a spin after work. With only the weekends open and your usual weather lottery, flying opportunities will be more limited. You might well ask 'Why bother?" so let's touch on that subject!

First, if you have never flown your gyro in really cold weather, you have passed one of life's great pleasures. EVERY aspect of a gyroplane's performance increases as by magic. Your blades come up in the thick air without real effort. Takeoff runs are extremely short (like 300 feet with no prerotator!) and climb rates are awesome. What' more, the chance of your engine getting overheated is just about zero. No matter how pleasant the summer handling characteristics of your machine, it will fly even better in the winter. If the performance boost isn't that tempting, ho about keeping current with your flying skills? Whether you admit it or not, you get rusty with a long layoff. Being able to put in some winter hours will retain your edge, giving you a jump-start in the spring when flying opportunities begin pick up again. I don't know about you, but my wife says I get very grumpy when afflicted by FDS (Flying Deficit Syndrome), so winter flying is simply my chance to contribute to family harmony!

Nothing about winter flying is as critical as developing the right mix of clothing. You won't enjoy the experience, let alone fly safely, if you aren't comfortable. Without an enclosure, you are going to be exposed to a 40-50 mph wind and the resulting wind chill factor would make headlines! The key is layering of clothing to keep heat in with a final layer to keep the wind out.

Your base layer should be a quality set of thermal underwear (high-tech long johns, for you sunbelt types). You will need one or preferably two pairs of thermal socks for your feet. Good leather boots will keep your feet dry in the snow, but they shouldn't be too high as they will inhibit precision rudder control. If I don't have to contend with deep snow, I will often wear a set of insulated running shoes to keep the old feet nimble on the pedals.

Heavy trousers, such as a reasonably new pair of blue jeans, will do for the legs. I will tuck the bottom of the pants legs into the outer pair of socks to keep the wind out. Up on the torso, a good wool shirt, followed by a wool sweater, will provide the needed layering. I avoid the fancy synthetics since, although they may look good, they don't retain the heat as well. If the temperature is in the 20s to 30s, a good ski parka can complete your ensemble. For really cold weather, you can zip into a complete snowmobile suit as an added layer of protection.

You will have to keep the wind off your face to avoid frostbite, and a basic ski mask will do the job nicely. Goggles are a must for eye protection. We use classic Silver Cross goggles, which are extremely comfortable but do restrict your peripheral vision a bit. Ventilated ski goggles are an excellent choice, as they will not fog up and typically are available with yellow and orange filters which can cut snow glare.

You will find your hands to be the most vulnerable point. With our old Quicksilver we used down snowmobile mitts, but these are clumsy on the flight controls of our gyro. There are a number of new model gloves out there that are insulated with Thinsulite that combine excellent flexibility and the ability to keep your hands warm. In really severe weather, you may want to add a large set of cloth work gloves to impede wind penetration. Ordinary wool gloves will NOT do the job and they are marginal even if you add an outer leather shell. Dressed as I have suggested, your hands, more than anything else, will determine how long you can fly and stay comfortable.

Obviously, if your winter weather is not as severe, you can ease up a bit in the clothing department but it is always better to over-dress a bit. Remember the awesome wind-chill factor, even on "warm" 40-degree days! The natural euphoria of flying will mask your initial perceptions of chilling, and when you do start to feel cold, it will seem to come on fast. For this reason, I would suggest that you keep your flying within a few miles of the airport so you can get back in a hurry when you first start to feel uncomfortable. Having a warm building or car to retire to will warm you back up, as will hot beverages. Remember, the idea is to have fun, so tailor your flying time so you stay comfortable.

Winter flying up where we live means that you are bundled up like the Pillsbury Doughboy. Between the clothes and your gloves, you will definitely be less mobile, and the ski mask and goggles will restrict your peripheral vision. At the same time it is just a little more effort to rubberneck, looking for traffic. Compared to the open feeling of summer, the initial effect is a bit claustrophobic until you get used to it. For this reason, I do not suggest you try it until you have a reasonable level of flight proficiency. You will be dealing with all sorts of new conditions and impressions, so flying the gyro has to be second nature. If you don't feel absolutely at ease, it would probably be best to wait out another season.

There are a few things that are quite unique about the winter flying scene. In the sections that follow, I will to touch on most of them.

Rubber parts like engine mounts, bungee cords, and grommets will get stiff in the cold, so take special care that none of these are cracked. There are not usually many plastic parts on a gyro, but some plastics do get brittle at low temperatures, requiring a little more attention. Ifyou can do the inspection in the relative comfort of the hangar, that's fine. Just don't forget to look your machine over between flights, even if it's a little uncomfortable.

Your engine is not likely to overheat under winter conditions, but will require some extra attention for other reasons. Fuel and oil will not mix as readily when it is cold, so take extra care to assure that your premix is, indeed, thoroughly mixed.

Since cold air is denser than warm, each intake cycle is bringing in more air with the same fuel charge. 'Me result is that the engine will run leaner in the cold than it will on a balmy day. We normally jet just a tad rich, so we don't compensate for this. If you have your jetting peaked out for summer flying, you may wish to raise the main jet needle by one notch or otherwise compensate with the mixture.

Pulling the engine through to thoroughly wet down the cylinders is a good idea prior to starting, as the oil on the cylinder walls will be pretty stiff. I don't have any experience with the Mac in cold weather, but the Rotax is quite easy to start, as one would expect from a snowmobile engine. Once the engine is running, let it warm up to 200 degrees or so on the CHT before loading it up, to avoid sticky rings and excessive engine wear.

The result is that you will be flying the rudder and rotor far earlier into the takeoff run. Fortunately, the takeoff run will be very short, compared with summer, so you won't have to dance to this particular tune for very long. If you have a clear, paved surface, there will be no problem, but be prepared for the dance if you hit a slippery patch. This lively behavior on a slippery runway is one of the reasons for specifying a reasonable level of flight proficiency for winter

Once off the ground, the hard part is over and the fun begins. Your climb rate will be simply awesome and the aircraft will have an extra-solid feel. You will be surprised how far you have to come off the throttle for level flight. Not only are you getting extra performance from the rotor in the thick air, the prop is getting an extra bite as well. All this contributes to outstanding flight performance.

Once you get past the amazement of how your machine is flying, you will notice something different about the world below! All summer long you are unconsciously using field colors and textures as a clue to orientation and navigation. With the landscape blanketed in snow, all those cues are gone. Keep track of where you are, for it will definitely take longer to figure things out if you do lose track!

You might not expect to encounter thermals in the middle of the winter, but you will! Thermals result from differential heating of the air and have nothing to do with absolute temperature. Winter thermal cells tend to be larger than those of summer, at least up here where we fly, but they are also more substantial as a result of the denser air. The large size of the cells means there is no "rocky road" feeling, and zones of lift and sink tend to be significantly smoother. When you combine the significantly higher climb rate in cold air with a boomer thermal, the result is quite an express elevator. You'll like it!

Landings will stretch out a bit in the denser air and some care will be required if you are landing on a snow-covered runway. The smooth, featureless surface lacks the textural cues to judge altitude and, much like water landings in a seaplane, it will take practice to judge your round-out. I would advise that you start your let-down very early in the approach, carrying a bit more throttle than usual. If you simply drop down toward idle and glide in, you will almost certainly cold-shock the engine and that's not good for its health.

You will note that I haven't mentioned skis yet, despite the fact that we still have our old Quicksilver skis. The previous two winters have not had a lot of snow and John Bergeon, the owner of our field, loves to keep the sod strip well plowed. This typically leaves just an inch or so of snow on the ground and that can be lost if you have one sunny afternoon. All in all, staying with the wheels has been quite practical.

This winter is shaping up to be a bit more typical, in terms of snow, and we are looking at ways to get the skis on and off in a hurry. Skis are the only practical way to handle deep snow and I can give you some advice based on our fixed-wing experience.

First, directional control on skis is even poorer than on wheels and, when taxiing slowly, you will probably need a frequent assist from the rudder, augmented by blasts from the prop. Once you get up a bit of speed, the skis are more like flying on the ground than a typical high-speed taxi, which means that you depend on aerodynamic inputs from the rudder and rotor system.

With substantial snow cover and a lack of crops, all those fields below you are potential places to land and take off again! Since most gyro pilots fly 100% from airports, let me give you a little advice, based on a decade of boondocks ultralight experience.

First, check the field out VERY carefully from the air. Generally, obstructions like power and telephone lines are easier to see with snow on the ground, but you still have to look! Stay away from the margins of fields, because fence posts and wires can easily be buried in snow. Assume they are there and they won't spoil your day. Drifted snow can also obscure things like tree stumps, feeding and watering troughs, and ditches that may be located out in afield. If the snow is deep enough, it may not matter, but it is foolish to take chances. The best approach is to check out fields earlier in the season so you won't have any surprises when you arrive. Getting permission, in advance, will also avoid the surprise of a trespass charge!

Snow-covered lake ice is an ideal winter airstrip. I would avoid bare ice, as you simply won't have adequate ground control. Add a little snow and conditions are almost perfect! 'Me ice is usually pretty smooth on modest-sized inland lakes, but large lakes can have mounded ice, particularly on the leeward shore. This can be difficult to see from the air, so keep a bit out from shore to give yourself a margin. A large field or frozen lake has the advantage that takeoffs and landings can always be into the wind, so cross-winds should not present a problem.

As I sit here and finish this up, it is only mid-November. Despite the calendar, it's 15 degrees outside and snowing again! No problem! If the weather breaks next weekend, Don and I will be out to fly. That, my friends, is the way to winterize your gyro!