Rocket Patents: SRB edition!

[RainDreamer]

Hello everyone, I have once again dug up from google patent various SRB-related invention that I find interesting. Not all of these patents are efficient, and might be outright useless, but it is awesome to see the advance of our technology marked by patents along the way. Without further ado, I present to you:

1. Nozzleless SRB (Published 2002)

A very interesting concept arise out of the need to cut every gram of weight possible. Here the inventors decided that, even though a nozzle is required for proper combustion and greatly increase efficiencies of rocket motor, it is still a lot of dead mass and adding more complexity to the rocket design. In a very kerbal manner, they decide to remove it, and use "a high burn-rate solid propellant matrix" (Read: very explody) to "eliminating the need for additional pressure inside the rocket motor and also eliminating the need to minimize exit turbulence in the exhaust gas flow". Even more kerbal like, they also imagine a "preferred" version of this SRB with the casing itself being made with solid rocket propellent (even more explody!), with lower burn rate than the one inside so that it covers the inner propellent while in operation (burning like hell up to the sky).

Can't imagine how this may go wrong!

2. Combustible case SRB (Published 2007)

A less kerbal-like version of the above. Invented by a different person, this one retain the nozzle and combustion chamber, but still attempt to have a combustible case, so that there is no more need for layers of insulation to the case to protect it from effect of heat, therefore reduce mass. The problem is, if you have a combustible case, how do you hold the nozzle and combustion chamber together? Wouldn't they just fall off as the case burn away? So the inventor devise a complex drive system using steel rods and gear train that spin real fast to pull them up as the thing burn to nothingness. I kind of suspect all the weight to the drive system to pull the nozzle up is more than the weight added by insulation layers...

3. Restartable SRB (Published 1967)

Anyone who uses SRB knows that when you light the thing up, there is no way to stop it - the whole fuel reserve will just burn till there is nothing left. Wouldn't it be so convenient to have an SRB that you can extinguish and reignite as needed? This inventor attempt to answer that question with the invention of the restartable SRB, using plugs. Yes, plugs. When needed, a huge plug is popped out while another plug blocks the nozzle and suddenly reduce the pressure in the combustion chamber, venting stuff out and extinguish the flame. Then when needed, they put the big plug back and remove the plug on the nozzle, igniting the fuel again using electric igniter. It is better for you to read the patent linked above itself to understand it fully than my amateur interpretation of it.

For more information and images, please click the links. They are quite interesting. You can also follow the citations at the bottom to other related patents and discover some interesting stuff, like this steam rocket and this disappearing gyro jet bullet (filed in 1965, 2 years after JFK assassination...hmmm)

Edited June 21, 2015 by RainDreamer

[sgt_flyer]

Mmmh guess those restartable SRBs are going to be something of the past, with Digital Solid State Propulsion product the Electric Solid Propellant thrusters

(Though, i hope they'll give some infos soon onto how well Spinsat performed, and the ISP of their thrusters )

Those would be a real boon for cubesats