Lake Amphibian Operational Tips – 3/10

Operational Tips For The Lake Amphibian – Part 3 of 10

AmphibianGuest Editorial Series by John Staber – Rather than go into details of checklists and run-up procedures, we will skip over to taxiing and takeoff. Since the nose gear is castering, steering is done with differential braking and one must be moving before the Lake can be turned. It helps to have the nose wheel pointed in the right direction before moving, especially in a tight spot. A healthy push on the side of the nose will usually do the trick. Using enough power to move forward, apply brake and rudder in the direction of the turn, and the opposite for changing direction.

A little extra taxi speed helps maintain direction. Do not “ride” the brakes. A bit of practice in an open space will soon have you comfortable. There is a damper to stop nose-wheel “shimmy” located just above the nose wheel fork. Too tight makes for difficult steering and too loose results in a “shimmy” at faster speeds.

There are springs attached to the pilot’s control yoke to enhance “feel” and the normal position is slightly nose down elevator, so for takeoff we want the elevator held slightly up. The trim tabs should be set in the top of the green arc, or visually about 40 degrees up. Bear in mind that there is considerable nose down thrust from the engine at full power.

Flaps should be in the down position for every takeoff and landing, land or water. Increase the throttle smoothly forward for takeoff. Stay off the brakes since you will have immediate rudder control. A bit more back pressure should have you flying at about 60 mph. Assume a positive climb angle, maintain 65 mph and retract the gear, and climb at 65 to 70 mph. The flaps are the slotted type, or slow speed, high lift variety. If you try to climb with very little angle of attack, the climb rate is poor.

However, by increasing the angle and climbing at the above speed you should see a respectable climb. After reaching about 500 feet of altitude, lower the nose to increase the airspeed, raise the flaps, trim down immediately, and climb at 85 or 90 mph. The main reason for not retracting the flaps until 500 feet of altitude is attained is to give the pilot time to select flaps down in the event of a forced landing after takeoff.

Control direction, thrust and “P” factor with the rudder only. When the desired cruise altitude is reached, lower the nose to level, allow the airspeed to increase to cruise, trimming nose down as speed increases. Finally, reduce the power setting to cruise power. If you should reduce the power before the proper attitude and cruise speed is reached you will be half-way to your destination before proper cruise airspeed is attained.

Landing gear, flaps and trim are hydraulically operated and reasonably trouble-free with a little preventive maintenance. Pressure is maintained by an electric pump operated by a pressure switch set to turn on at about 700 psi and off at about 1100 psi. There is a hand-operated auxiliary hydraulic pump in the event that the electric pump fails. An accumulator in the system assists in rapid gear retraction and extension. Preventive maintenance generally consists of occasional “O” ring replacement and periodic replacement of flexible hoses.

The Lake is a “rudder” airplane and one of the best aircraft to demonstrate adverse yaw with. If one attempts to turn with aileron alone, the nose immediately slews in the wrong direction and stays that way throughout the turn. Almost perfectly coordinated turns can be made with the rudder alone, and due to the dihedral of the wings will remain in a turn when properly trimmed with no input from the pilot. Look for Part 4 of 10, next Wednesday!

LakeText 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.

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