Patent Figures

The patent office website uses a weird version of TIFF files for their images. So I am going to put my figures here. And some explanations that might be clearer than the patent language. Eventually I'll put something up on my personal homepage.



I'll put the other figures behind the cut.



Figure 1 shows the parts of the rocket. A is the nose cone, glued or taped to the rocket (this would make it crash if we weren't such darned clever inventors). B is the little hole that makes our invention clever--it acts like a little thruster at ejection. C is he body tube--it has to e long and skinny. D is the launch lug--standard equipment on any model rocket. E are the fins that have to be big enough to work when the rocket is pinting forward, but not big enough when it is moving sideways. F is the rocket engine. G is an engine block to keep the engine from going forward during boost.



Figure 2 shows the filght of the rocket. H is the rocket flying under boost. CG is the center of gravity, the balance point, or more importantly, the natural pivot point of the moel in flight. BCP is the Barrowman center of pressure, where the air rushin past acts on the model, on average, when it is going forward. Note that it is behind the CG, meaning the air pushes the rear of the model backwards, blowing on the fins, so the rocket goes straight. This is normal rocket (and arrow) stability. CLA is the center of lateral area. That's where the wind acts on the rocket when it is going sideways. It doesn't matter when the rocket is going forward like in H and I.

I is the coast phase. It's like the boost phase, except that the CG has moved a lttle forward because the engine is out of propelllant and weighs less.

J is the moment of truth. The engine's ejection charge, which would normally pop out a parachute, blows out the little hole at the front of the tube. That sends the rocket ass-over-teakettles around the CG. As a result, the model points sideways, and the wind acts on the CLA, pushing the front of the model backwards. K is where the model glides backwards for a gentle landing on the ground.



Figure 3 simply illustrates that the fins don't have to be square, and they don't have to be identical. Bob had a theory that with on smaller fin, the rocket would be less likely to spin on the way down. It's not entirely clear it it would--we never really tested the idea seriously.