Solid fueled rocket motors with pintle nozzle controlled thrust

[Eddyxz]

Hello everybody, I want to talk here about solid propellant rocket motors (propelling missiles or space vectors) using pintle nozzles to control thrust.
The concept is quite simple: they partially occlude the throat area of the nozzle, with an axial movement of the pintle, gaining thrust because of the increment in combustion chamber's pressure and the consequent increment in burning ratio. In order to decrease thrust, the pintle moves backwards and the throat area is cleared.
This technology is very useful for making tactical missiles more flexible and agile, in fact with a control on thrust it is possible to hit a nearby target very rapidly, increase range by decreasing thrust and vary the turning radius in steerings; it is also used in space vectors and in landing modules for more precise landings.
Up to now I've been able to find just two rockets with pintle nozzles: the NLOS-LS PAM (Non-Line Of Sight Launch System Precision Attack Missile) and the Orion's LAS (Launch Abort System) and I'd like to know more rocket motors provided with this technology, their manufacturers and their specifications.
Thank you for answers.

 

[Quiller]

Hello everybody, I want to talk here about solid propellant rocket motors (propelling missiles or space vectors) using pintle nozzles to control thrust.
The concept is quite simple: they partially occlude the throat area of the nozzle, with an axial movement of the pintle, gaining thrust because of the increment in combustion chamber's pressure and the consequent increment in burning ratio. In order to decrease thrust, the pintle moves backwards and the throat area is cleared.
This technology is very useful for making tactical missiles more flexible and agile, in fact with a control on thrust it is possible to hit a nearby target very rapidly, increase range by decreasing thrust and vary the turning radius in steerings; it is also used in space vectors and in landing modules for more precise landings.
Up to now I've been able to find just two rockets with pintle nozzles: the NLOS-LS PAM (Non-Line Of Sight Launch System Precision Attack Missile) and the Orion's LAS (Launch Abort System) and I'd like to know more rocket motors provided with this technology, their manufacturers and their specifications.
Thank you for answers.

The use of pintle nozzles, by themselves, for tactical battlefield missiles is not as effective (in theory) as using thrust vector control, or TVC. Together they can increase agility of missiles and target accuracy. TVC is used on jet aircraft like the F-22 Raptor for rapid attitude changes. Pintle nozzles with TVC can do the same for missiles as you pointed out.

TVC in one form or another has been used on ICBM's for some time, although using different technologies to achieve thrust vector control. Minuteman II used fluid dynamics to accomplish this. The Trident series of SLBM's use TVC as well, though using different technology.

Very probably pintle nozzles, TVC, a combination thereof... or some more exotic thrust vectoring solution is behind Russia's most recent claims of anti-ICBM missile avoidance claims for their nuclear warheads.

The NLOS LC-PAM system was defunded in mid-2010 for cost overuns and a number of technical problems.

Adapting pintle nozzles with TVC could be useful in battlefield ballilstic missiles like Russia's Iskander and similar missiles fielded by other countries.

I don't know offhand if US tactical nuclear missiles (like the Patton) used some form of thrust vector control, but they well might have.

 

[Eddyxz]

Yes I know TVC systems which permit vectoring the thrust by gimballing the nozzle, injecting fluid asymmetrically in the exhaust, channelling the exhaust into vanes and stuff; but my research is about throttleable rockets, that is controlling the intensity of thrust and not its direction and I'm particularly interested in knowing other rocket motors provided with pintle nozzles.

 

[rajkumar.ar]

Pintle control and TVC

hi firends,
As per my knowledge, TVC, thrust vector control and Pintle control are two different approaches. TVC is using for steering a single nozzle solid motor in a missile or launch vehicle. TVC uses an explosive liquid, such as Strontium prechlorate. we just inject this Strontium perchlorate on a particular portion of the nozzle divergent region (for sold motors/rockets). this liquid create a flow separation and suddenly a pressure spike, called shock. due to this pressure hike, an extra thrust will be produced in that particular region, creating a side thrust for steering the rocket.
Flex nozzle system similar to Gimbal control is also using for steering a single nozzled solid motor.
Pintle type control is a complete control of the throat area of a rocket motor. If we are using a single nozzled rocket motor, only thrust control in axial direction is possible with pintle control. NO side thrust will be produced in this case.

Orion's Attitude control motor is an example, with 8 Nozzles, placed 90 degree to the motor axis. Its just an engineering marvel.

Regards
Rajkumar a r.
rajkumar.ar
@
gmail.com

 

[LocoyData]

I just required some information and was searching on Google for it. I visited each page that came on first page and didn’t got any relevant result then I thought to check out the second one and got your blog. This is what I wanted!

 

[rajkumar.ar]

Thrust control in solid rocket motors.

Internal control of solid motors are very difficult due to high temperature and pressures, also errosive environment. Are you trying to demonstrate such a system or doing theoretical work? on it?


QUOTE=LocoyData;260338]I just required some information and was searching on Google for it. I visited each page that came on first page and didn’t got any relevant result then I thought to check out the second one and got your blog. This is what I wanted![/QUOTE]

 

[NobodyMinus]

I think you may be misunderstanding how pintle nozzles work. They don't allow one to control thrust in a solid-fuel rocket the way you would in a liquid fuel rocket. It only sort of allows thrust control by controlling the efficiency of altitude compensation. It isn't really thrust control in the traditional sense; while I don't know as much about low altitude rockets, I know OLVs only vary their thrust by around 30% depending on altitude, and I'm guessing because low altitude rockets go through a much smaller range of pressures that this range would be lower for systems of the type you are describing. What I've mostly heard is that the real advantage you'd get out of a pintle over a traditional bell is fuel efficiency, not thrust control.

On your question about other pintle designs, I believe REL's SABRE air-breathing rocket uses a pintle