Maxim's Test Rig

These two photos of Hewitt Phillips' peanut scale model appeared in "WWI Aero" # 120, July 1988, along with these editorial comments.

Not too many photos of the Maxim machine in flight. Hewitt Phillips used two hollow motor sticks to replace Maxim's steam engine. His 13" span peanut model flies very well. Hewitt thinks the large props aft of the CG give adequate directional stability, the Maxim's dihedral does the rest. The model is sensitive to differential thrust - perhaps Maxim's intention was to control it this way? 

The relative density factor of the model is almost exactly equal to that of the full-scale Maxim machine. The stable flight characteristics of the model would therefore be expected to resemble those of the full-scale machine.

I recently wrote to Hewitt Phillips to learn more about his Maxim model and he kindly sent me this reply...

I heard of there being an article in "WWI Aero" issue #104, April 1985, about Hiram Maxim. Indeed, it contained an excellent article by Herb Kelley, and included good drawings of Maxim's airplane.

Click on the image to download a 1000 pixel wide plan.

I decided to build it as a peanut scale flying model and just enlarged the drawing in "WWI Aero" to the correct scale. The model is 1/96 scale, probably the smallest reduction ratio of any peanut scale model. Unlike most rubber powered models, it uses true-scale propellers.

I added a couple of light hollow-tube motor sticks that are attached to the model by tissue paper tubes that engage balsa struts similar to those used to hold the wings on indoor models. The rubber motors are wound with the motor sticks off the model. A little sliding wire stop is placed near each propeller hub to keep the propellers from turning while the motor sticks are assembled on the model. Then the stops are carefully released while holding the propellers and the model is launched, somewhat like a twin pusher.

On the model, the front canard surface was incorrectly placed a little too far forward, I later changed it to the correct position (as per the plans) with no effect on the flying of the model.

The model is covered with superfine tissue and all brace wires are omitted. The flying weight is 3.2 grams, which turns out to be closed to that required for true dynamic scaling.

Hewitt Phillips
Hampton, Virginia
USA

email aerohydro