TundraShark

Concept for an amphibious aircraft float/ski.

Float Top
Float Bottom

This is a rough approximation to the float configuration. There will be a wheel protruding from the float centered near the back of the two mini-wings. It will also have a tail wheel protruding through a tail ski like planing surface at the rear. A little better example can be seen at Waterbug Aircraft. The little wings just represent what is needed to support the aircraft when it is on-plane. They will be incorporated into the float/ski bottom because they would be a problem on rough ground or rough or deep snow. The bottom of these foils follow an equation for the shape which give minimum drag for a planing body. I found this NASA technical report TECHNICAL REPORT R-93 from 1961 in which they gave the equation and performed experiments which showed a large reduction in drag. I have noticed this shape on the tail of some new power boats. The center flat area of the ski will be covered with a replacable Ultra-high molecular weight plastic sheet as is used on snow ski bottoms and truck bed liners. There will be a suspension system allowing operation on rough terrain/snow as well as water. The first design will be for the light sport category with mountings for common existing aircraft.

I am working on modeling the float and aircraft dynamics with Blender 3D animation software which has the Bullet physics game engine incorporated. So far I have modeled a 1946 Aeronca Champ on regular landing gear, Federal 1500 skis and PK floats. I made them roll or slide down a ramp and go over some rough ground. I have written python scripts within the game to model the exact configurations of the spring/shock and wheel/ski rotation, including the front ski bungee and rotation limit cables. I added the ability to use the up and down arrows to increase and decrease engine thrust so that I could make the aircraft keep going until it falls of the end of the world ;^) I have yet to model water for the float plane or model aero lift and drag. I have made all of the control surfaces controllable, however, so that I can make a flight simulation later. Buoyancy modeling can be seen in the simplebuoy.blend file. Tie the buoyforce.py python script to an always sensor for the object to float. You should have a mesh which has no more than 2 faces per edge. I have tied it to the excellent plugin for waves found at www.ashsid.sk in the WaveBuoy.blend file.

Some screen shots. I have yet to render any animations. (click image to zoom)

Aeronca on Wheels Aeronca on Skis Aeronca on Floats

Links to the .blend files (You need Blender 3D to use them) follow: On Wheels, On Skis, On Floats

This work is in support of my main ongoing project to design a plane I call the Waterbug , for the Light Sport category.

Waterbug Aircraft

I recently found an old document on an aircraft I designed in 1982 called the Speedolight , for the Ultralight category.

Photo Album

Photo Album

pgm416@tundrashark.com

Copyright 2011 © Patrick Moore, All rights reserved.

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