Aircraft Performance

Okay.  So, if you’ve come to this page hoping to find data that will help you benchmark the performance of your plane, or to compare “official” data of performance at sea level with a 182 on amphib floats, you are going to be disappointed.  What you will find here is summary of the range of performance values that you might expect, and the reasons for their high variability.

Most people care first about the “headline” performance values – cruise speed, useful load, range, service ceiling, climb rates, stall speed (dirty), take-off distance (raw and over 50’ obstacle) – things that help them define their mission. Only then do they start to think about factors that can affect those base values. Within any one model of the Lake family, the answers that you will find will vary widely, depending on how the plane is equipped. For example, is the plane equipped with fuel floats or wet wings, batwings, VG’s, stabilizer seals, or any one of many other potential variables.

Before we get into the details, we should recognize that generally all values improved as the models evolved from the C-1 Skimmer, to the LA-4, to the LA4-200, to the EP, and finally the “Renegade” family.

So let’s get started:

  • Cruise Speed: ranges from 100 mph for the Skimmer, to 110 mph for the LA-4, to 105 kts for the -200, and 118kts for the Renegade. Individual aircraft may see values +/- 10%, and turbo-equipped aircraft should see +/- 15% improvement at altitude.
  • Useful Load: is defined as the difference between certificated max gross weight and the empty weight of the plane, and will range between 650 and 1150 lbs.  Very few planes actually weigh out at the “factory empty weight”.  Intended passenger/baggage weight will often result in a reduced fuel load.
  • Range: is defined as full-fuel at max economy power settings.  Given the various fuel tank options for each model, ranges can vary tremendously, also affecting the useful load for the trip!  Values can range from under 500 miles to over 1200 miles.
  • Service Ceiling: most normally-aspirated Lakes perform best up to 6000 feet, after which climb rates deteriorate significantly, but can generally get up close to the oxygen-required levels.  Turbo-equipped planes can get up to the flight levels (18,000 ft).  If you are planning on flying out in the mountain West, a turbo-equipped plane is a definite advantage.
  • Climb Rate: all models can generally maintain climb rates of 500-700 fpm up to 6000 feet, at max gross weight.  But don’t plan on that if density altitude is a factor.
  • Stall Speed: will range from as low as 40 mph (dirty) to as high as 53 kts, depending on the model, and how it is equipped.  VG’s and/or batwings will enhance this performance immensely.
  • Take-Off Distance: this is probably the most highly debated variable to consider. From a dry asphalt runway, at max gross weight, most models will be airborne in 700 ft or less, and clear of a 50’ obstacle in 1200 feet or less.  Reduce the weight, and performance can be even better.  However, from the water, the picture can change radically.  Generally, water take-off distances in ideal conditions will increase by 25-30%, but if you add in density altitude and water surface conditions, required distances will increase exponentially, even to the point of being unable to get airborne.  This is primarily due to the suction effect of the water on the hull.  There are minor modifications and techniques to minimize this effect, and good training from a Lake specialist will help.

One thing that is a FACT, is that no Lake will ever win the award for speed – it is simply pushing too much air. Compared to a “normal” aircraft with a tractor-mounted engine, the Lake has to overcome the additional surface area of the wing floats and the pylon-mounted engine, while also paying a penalty in engine efficiency due to the “dirty” air around the cowling affecting the efficiency of the prop and a compromise in the engine angle of incidence.

As long as there have been Lakes, their owners have tried to find ways to squeeze an extra knot or two of performance. One gentleman literally took a saw to his plane (N550YS), and rebuilt it as an “experimental”, incorporating every possible idea into his “Super Buccaneer”. It included retracting wing floats, main gear doors, an IO-550 300 HP engine in a streamlined cowl, and many more small changes, as a result of which he gained about 15 knots. Sadly, the Super Buccaneer was totaled in an unfortunate accident.

Hopefully, this summary has provided enough information to help you ask the right questions when evaluating the suitability of the Lake to meet your flying mission needs.

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