Baby Mixmaster - rubber pusher model with contra-rotating props. July 1947 MAN.
Quote: - "Do you want more speed plus stability and complete elimination of torque? Well, here is the answer in a contra-rotating prop arrangement for rubber powered models. As we all know, torque is an important factor in designing models. With torque eliminated, model building is a pleasure and flying is a greater pleasure. This model was designed after gaining experience on contra-rotating prop arrangements as applied to gas powered models.
In designing this model and the contra-rotating prop arrangement, I had to contend with weight which I have kept to the minimum. The completed model weighs 5 oz. Taking into consideration the ball bearings, flanges, plugs and tub-ing, this is very light indeed. Although this model was not designed for endurance, it is far from a short distance flyer as your test flights will prove. In three different tests, with only 150 turns, my model averaged over 200 ft at about fifty feet altitude and flew in a very stable manner at high speed. Using 1/8in flat rubber (12 strands), maximum turns should be 200 and care should be taken not to exceed this limit until you are sure of your rubber.
This model is of very simple construction and should give little trouble in building. The contra-rotating mechanism may appear a bit difficult, but upon closer examination you will find that it is a simple affair. All parts such as flanges, bearings, tubing and the shaft, which is 1/8in drill rod, are of standard make and can be purchased at low cost.
Fuselage construction: Start in the usual manner by laying out the two sides and allowing them to dry thoroughly. Then remove from drawing board and add top and bottom crosspieces as shown on drawings. The dimensions at each station, both on side and top views, show the distance from outer edge of the longeron to centerline of the fuselage. Thus, to get the full size for the uprights, add the dimensions on top and bottom and subtract double the thickness of the longerons. The next step is to shape a nose block as illustrated from solid stock. The tail block is carved in same manner as nose block, and both are sanded to a fine finish..."
Update 10/01/2018: added article, thanks to RFJ.
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