Lake Amphibian Operational Tips – Part 7/10
Written by John Staber : The water takeoff. If you are going to get into trouble, this is probably the place where it is most likely going to happen. And the biggest reason is that one can over-step his ability to handle rough water. Proficiency is the keynote here. Proficiency mixed with exact attitude control, and over-controlling the elevator is the biggest culprit. While this operation does require full power to transition to the “step attitude” and also to lift off, it does not mean that power cannot be reduced while “on the step” in order to judge the proper attitude and water conditions, before applying full power again for lift off. Several items are very important. Lots of up trim is needed (remember the nose-down thrust from the engine). Attention to attitude is vital. As when driving a car, the faster you are going, the farther out front you should concentrate your gaze.
Several years ago I was instructing someone who said that they were having problems with rough water takeoffs. Rough water being 1 foot waves or more. I found the problem on the first takeoff due to being thrown off the seat and around the cockpit regardless of the seatbelt. I looked for something to hold onto and the only thing available was the control yoke which I held onto for dear life, which in effect stopped the pilot induced up and down pitching of the nose, and made the ride much more comfortable. We stopped the takeoff and started over again, this time with the pilot concentrating on a point in the distance and holding a constant attitude, instead of adjusting pitch for each and every wave going under the hull. A classic case of over-controlling the elevator!
Under reduced power, reasonably slow (35mph) step taxying one can do almost anything with the Lake, from full up elevator to full down elevator with no problems, but with full power and higher water speeds, it has to be controlled correctly.
Having done all necessary checks, add full power slowly with full up elevator. When the bow wave clears the nose gear doors, relax back pressure and allow the nose to come down to the level (step) attitude. Just before reaching this attitude, apply a bit of up elevator to prevent a porpoise. Should it start to porpoise (like a nose-heavy motorboat), increase the amount of back pressure and it will stop immediately (reducing power also has the same effect). Allow the speed to build, slowly adding more back pressure as the speed and water drag increases, but do not change the attitude, and the Lake will fly off by itself when it is ready. As previously mentioned, looking off in the distance will help detect any attitude changes. There is a “sweet” attitude where you will accelerate rapidly, and it is quite obvious. Do not rotate off the water. Doing so will result in the tail going down and slowing the aircraft and it could result in a premature liftoff. Allow the water to drain off the hull and climb at 65, just as from land. Do not be a hurry to raise the flaps as generally there are obstacles to clear and you are going to make another water landing anyway since it is so much fun!
There are several items to think about. One is, that the nose down thrust actually helps to get on the step by pressing the hull down onto the water and allowing the “V” of the hull to cut through the waves. It has been my experience with a heavily loaded 180 horsepower Lake, that it would not get on the step in high waves, no matter what I tried. Once we reached smoother water (6″ waves) it slowly reached the step attitude and off we went (with not much room left, I might add). A note here also. It is amazing that 180 horsepower is enough to make the Lake perform as well as other aircraft with well over that amount of horsepower. Of course, the 200 and 250/270 models do even better.
It is well known among seaplane pilots that on a windy day there is a rogue wave about every 25 to 30 waves…one that is a bit higher than others. As your speed increases one must be careful not to get launched into the air by this wave before the aircraft is ready to fly. A slight relaxation of back pressure is needed as you cross this wave with no change in attitude and you will stay on the water until lift-off. Should you inadvertently get launched out of the water, it is imperative that the attitude remains the same (the water landing attitude) as you are certainly going to contact the water again until your speed increases enough to fly. The ability to “read the water” is a must and can only be gained by experience, hence it is your proficiency that dictates the type of water you fly from, or on to.
Aborting the takeoff. It is my humble opinion, that when one is approaching imminent lift off you are committed to the takeoff and the attitude must remain the same until you do lift off. If you are going to abort the takeoff, you must do it long before this point. Why? The lack of the nose down thrust near takeoff speed will result in a takeoff anyway with no power to maintain forward speed and the ability to fly away from the water. Bear in mind that I am talking about a “worst situation” scenario and that only if you have exceeded your abilities, are you ever going to get into this situation. Beware the boat wake. If you see a lot of boats moving on the water, you are going to find boat wakes and they can be lethal if encountered on a full power takeoff run. Abort the takeoff early on in the run if possible and keep your speed well below takeoff speed until you have a clear area of no wakes. If at all possible, parallel the wakes, remembering to turn with the rudders and encounter them at slow speeds (I call it wallowing through them). If you don’t like the situation, stop. Do not wait until you are way beyond your limit of proficiency.
Text and pictures courtesy and copyright of John Staber, Owner of Colonial Skimmer SN #1; John has flown and worked on Colonial Skimmers since 1964 and has accumulated more than 5000 hours in all different makes and models. In 2011 he published a book on the restoration of N6595K which can be purchased on his website. If you are interested to learn more about Skimmers and Lake Amphibian Aircraft, there will be one new article per week, dealing with a new topic.