Echo - Landing Test #6

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Winston

Winston

Lorenzo von Matterhorn
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Reliably precise soft landing with a solid motor was predictably impossible - no control over thrust; motor production variations and ambient temperature caused propellant characteristic variations produce unknowable in advance variations in actual thrust curves. He's now going to a liquid bi-propellant engine, throttleable LOX/methanol, 100lb thrust, 300 psi chamber pressure, film cooled in combustion chamber, nozzle regeneratively cooled.

 
Sorry to see he shut down the model rocket powered landing project. But I figured as much from early on, several variables that would make a successful landing more of a luck thing. I wish he had tried a "Krushnik effect" sliding tube going past the nozzle to try to vary the thrust.

Look forward to his future projects.

And it is still incredible that he is selling flight controllers for doing gimbaled rockets, that unfortunately not many have obtained to use. THAT is "Level 5" stuff, Level 3 is boring by comparison.
 
georgegassaway said:
I wish he had tried a "Krushnik effect" sliding tube going past the nozzle to try to vary the thrust.
Click to expand...
I thought of exactly the same throttling method. I think that I might have even suggested it under one of his videos (buried within a bazillion other replies). It could be used to eliminate his hovering near ground level issues, as shown in that video, assuming that his barometric altimeter was accurate enough, possibly being negatively influenced by rising hot exhaust, especially when close to the ground. LIDAR would be nixed by exhaust smoke, ultrasonic ranging would probably be swamped by motor noise. Maybe the accelerometer could be used.
 
Winston said:
I thought of exactly the same throttling method. I think that I might have even suggested it under one of his videos (buried within a bazillion other replies). It could be used to eliminate his hovering near ground level issues, as shown in that video, assuming that his barometric altimeter was accurate enough, possibly being negatively influenced by rising hot exhaust, especially when close to the ground. LIDAR would be nixed by exhaust smoke, ultrasonic ranging would probably be swamped by motor noise. Maybe the accelerometer could be used.
Click to expand...
i had to go read up on "krushnik effect", fascinating stuff. The below link also mentions "bernoulli lock" which i bet was really weird the first time it was seen hah
https://rocketry.wordpress.com/2006/10/17/the-krushnic-effect-and-the-bernoulli-lock/
 

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