Northrop Eagle II (oz6557)

About this Plan

Northrop Eagle II. Radio control sport (fantasy-scale) model.

Quote: "I've been modeling for six years now and my efforts have produced a line of high wing trainer types that perfectly satisfy my love for the Golden Age of aviation. But my son Adam, who in reality has just turned 13, has expressed little interest in models of aircraft that pioneered the skies 40 years before he was born. He has dutifully followed me to the fields and lakes and even learned to fly, but the inspiration to really grasp this hobby and all the enjoyment it can provide has eluded him. I determined that if Adam was to ever develop an interest in model aviation, the model would have to be of a plane that kindled his imagination and the dream of the Eagle II was born.

This spring I found myself staring at a just completed Fairchild Ranger 24. I was totally exhausted from having built it, so as any good modeler would do, I sat down for a minute and began to ponder the next plane. Adam was in the shop and I called him over for what was the first of many rewarding experiences with this project. As we began to page through our collection of catalogues and 3-views, the parameters for the project quickly evolved. Adam could decide how the plane would look, but he would bow to the determinations I had to make in order to give him an airplane he could fly. By the end of that first session, we had a plane on the drawing board that met our criteria. The model was basically a sheep in wolf's clothing. Our spirits were high, and we were ready to begin building.

Within a week, all of the boxes had arrived at our doorstep but it was the O.S. Wankle that we opened first. I must admit to being only a novice regarding 2-stroke engines and a total stranger at the time to Wankles. O.S. provides an informative booklet giving proper break-in procedures, fuel and prop requirements, maintenance and a brief history. However, they provide no data as to the internal workings of the engine and this is somewhat disconcerting when you find little wrenches in the accessory package that won't fit anywhere on the outside of the engine. I suspect the wrenches are used, at some point, to adjust or replace the spring loaded rotor tip seals that provide the compression but that's only a guess. This is a fine, powerful, quiet engine that deserves to be considered by more modelers, and I feel that exploded views and adjustment instructions would broaden its appeal considerably.

I made a test stand for the Wankle and mounted a two ounce tank for break-in. It should be mentioned right here that the Wankle must be started with an electric starter. The starter will fire it up immediately the first time and every time. For the break-in period, I mounted the engine with the muffler low and on the left side, facing the engine, as per the instructions. I ran it slobbering rich for two minutes at a time for a total of 30 minutes at, or near, full throttle, and then another 30 minutes at varying throttle settings. We've used K & B 100 for break-in and Tower's 10% nitro for flying, which provides all the power we need. This is a .30 size engine that spins out nearly 1.3 horsepower at 18,000 rpms. Check those figures against a hot .40 sometime and you'll be pleasantly surprised.

There are certain characteristics of the Wankle that should be addressed to make you feel more comfortable with it. First of all, it likes to run hot and needs adequate cooling. O.S. recommends very little cowling and the use of a very small spinner, if any, to accomplish this and I agree..."

Scanning by Don at EAC, cleanup by theshadow.

Supplementary file notes

Article pages, text and pics, thanks to JHatton, AugustaWest.

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