[with contributions from Skip Pothier and John Hawkins]
Most float fliers think that the season is over once the birds have flown south. Not so, just wait for some snow and the fun starts all over again. Both float equipped planes and flying boats love fresh, soft snow.
However, the first lesson to learn is that not all snow is created equal. Hard-packed snow, especially old stuff that has gone through the freeze/thaw cycle, is very tough on floats and should be avoided – try skis instead.
For fun winter flying, choose a nice sunny day with the temperature just below freezing. To minimize wind chill, hope for very little breeze. You will be amazed how much the sun’s radiant energy keeps you warmer than the same air temperature with cloud cover. For all practical purposes, the lower temperature limit is minus 10 Celsius (14 degrees Fahrenheit) – below that point the fun/pain ratio deteriorates rapidly.
What is needed is a fresh snowfall of deep powder to really show how good floats are on snow. With deep powder conditions, most RC planes on skis sink too deeply, the propeller hits the snow or the plane simply nose dives into the snow as soon as power is applied. Not so with floats.
Floats just see the soft powder as crystals of water and ride up on top with no effort at all. In fact, if you have Ernst type rudders with rubber band tensioners, the water rudders even work!
There are basically two types of floats that you might use on snow. First, the plastic manufactured variety are quite rugged and will take a lot of punishment as long as the temperature is not so low that the plastic fractures – usually your fingers freeze well before the floats crack. Second, the foam core or built-up type that are covered with film or a paint and fibreglass combination. The film cover is quite sensitive to “nasty” snow and should be used only in pristine powder. The fibreglass finish can take more abuse, but not as much as the plastic.
As a generality, use a set of floats that have some “experience”. You can always run a strip of duct tape down the keel if you are concerned about wear – just make sure to warm it with a heat gun when you take the tape off or you may take off more than the tape!
Another thing that you will notice is that the plane takes off in no distance at all and that is when you remember the theory of Density Altitude. There is a huge amount of difference between the lift generated on a hot, muggy day and that available on a crisp, sunny winter day. When you come in to land, you will note that it will float in ground effect much more than in summer. Be prepared to land long!
If the snow is anything but really fresh, another thing to keep that in mind as you make that perfect landing is that, unlike water, there is very little friction to grab your floats to slow you down. You will bounce back into the air if you are just a smidgen too fast. So, you really have to hold it off just a tad above the snow until it literally stops flying and settles in perfectly. In perfect, light, puffy snow anyone can make a good landing.
Now that you are smitten with the prospects, here are a few tips on cold weather flying.
- Pick a calm, sunny day after a fresh powder snowfall with a temperature just below freezing.
- Dress for the occasion. Hypothermia does not improve your flying.
- Fill up the fuel tank before you leave home. You want to start that motor as soon as possible and this is one less task to try with trembling fingers. Wet fuel on bare hands is discouraging.
- If you use a hand-held nicad glow ignitor, put it in your pocket to keep the battery warm. As “Dr1 Driver” says, make sure you have no car keys or spare change in that pocket – things could get warm “shortly”!
- Use a kid’s toboggan to move your flight box, starter and sundry equipment over the snow. Attach a looped towrope from the toboggan to the propeller of your plane and glide effortlessly over the snow.
- Wear thin gloves – only the bravest go with bare hands. If you use a mitt that covers the transmitter so that you can go without gloves, follow this safety tip. Loop a #64 rubber band around the left side of the transmitter carrying handle. Then loop another #64 band to extend the first one. Take the length of rubber down the back of the transmitter and bring it under the bottom and loop it over the left hand (throttle) stick so that the throttle is held firmly in the idle position. Flip the band off the throttle once you are safely inside the mitt. It is all too easy to accidentally hit that throttle stick into full throttle while you are struggling to get into the mitt – your colleagues will not like a runaway plane.
- Do not take the warm plane directly from the car and plunk it on the snow – the warm float bottoms will melt some snow, then refreeze and the float bottoms will be covered with “snow sandpaper”. The coefficient of friction will be very high and you will find movement quite difficult. Hold you plane in the cool breeze for a couple of minutes and then set it down. If in doubt, check the bottom and clean it off. Before leaving home, some folks like to rub some paraffin wax on the bottoms or to spray them with silicon to minimize snow stick and drag.
- Make sure all your batteries are fully charged. Cold temperatures decrease the effectiveness of batteries.
- Do not use fuels with castor oil – it congeals at lower temperatures and makes it hard to start the engine. Use synthetic lubricant instead.
- Be prepared to richen (open) the needle valve quite a bit (8 clicks) from summer settings.
- With the glow driver off, flip the propeller several times. The friction will warm up the cylinder and reduce the amount of power consumed by your electric starter. Flip starting a cold engine is an art possessed by few mortals. Cheat and use a starter!
- Do not let the rubber cone of your starter get wet – i.e. don’t drop it in the snow. An invisible film of ice will form and frustrate your starting efforts. To get rid of the ice, stick a gloved finger of the opposite hand into the cone and spin the starter. The resulting friction will do three things: get rid of the ice, warm up your finger and start to wear out your glove.
- Have some lighter fuel ready to squirt into the carburetor throat. Lighter fuel vaporizes better than glow fuel at low temperature and will assist a cold start.
- When starting, you will probably have to “choke” the engine by putting a finger over the muffler exhaust tube.
- Fuel up again as soon as you finish a flight. Get that engine going again before it gets cold-soaked.
- Have fun.