Can We Do This

[COSTransplant]

Ok, since my brother got me back into rocketry, I've nopt been able to eat or sleep -- it's terrible. Anyways, I have a question. Can we make a rocket that does what is shown in the SLBM launch video below? Basically, can we make a model rocket that is bumped off the launch pad with say, a CO2 cartridge, the CO2 cartridge / booster is kicked off by an ejection charge, and then the the first main engine(s) ignite and then the second stage engine(s) ignite.

 

[dhbarr]

If I were going to try this, I'd practice standard staging first. Then, since I'd need some sort of electronics to ignite the second stage, I'd look into tilt inhibit.

Either way, for safety both parts of your boost should be upward, not tipped over

 

[loopy]

I don't know of any way to get something off the pad quick enough and to have enough and speed over the fins to remain stable for the engine ignition (other than using a first stage engine). Short answer - I'd say no...as would pretty much everyone I've ever seen running the LCO table...

 

[jimzcatz]

Have you lost your mind?

 

[cls]

I bet it could be done... a friend used to launch an Alpha III, submerged in a bucket of water. Surprisingly the extra drag didn't affect the flight much. so, how about a CHAD staged 3FNC, use a 1/2A6-0 on the bottom.

 

[Grog6]

I always wanted to do an array of A engine rockets, in tubes on a wagon, that popped out of a covered tube. I tried to eliminate the launch rod for the tube, and it did not work, lol. I even figured out how to use baloons as 'weather covers', and launch thru them. Project vetoed by dad, lol.

 

[Voyager1]

Have you lost your mind?

Given that the OP has posted this question in the HPR forum, you may have a point! I doubt whether any normal club launch would sanction this.

 

[cwbullet]

I am sure you can find a way, but probably cost prohibitive and might be unsafe.

 

[Donnager]

I think Mark Rober has made a silo launched rocket.

 

[waltr]

Under water Silo launch has been done even back in the 1960s as a science fair project.

Air pressure boosted then ignite motor is much harder.
Do watch the titan start arcing over when the motor light. The Active Control system then straightens out the trajectory to near vertical. Since air speed is very low the control system must use Thrust Vectoring.

Will not say this can not be done, it will just be very, very difficult.

 

[COSTransplant]

I think Mark Rober has made a silo launched rocket.

Thank you for sharing this -- it is exactly what I was thinking (in concept). A cold launch. That is the term that I was looking for.

 

[COSTransplant]

Have you lost your mind?

And yes, I have probably lost my mind. But as someone who -- in a previous life -- evaluated the technologies behind Warsaw Pact missile systems, I can't get the idea out of my head.

 

[SDramstad]

I wouldnt try it but whatever rocket you use would have to have active stabilization. Unless the initial gas charge puts it at the same velocity a normal rocket would hit at the end of the rod.

 

[Steve Shannon]

I think Mark Rober has made a silo launched rocket.

The owner of RocketSilo (a pretty large rocketry vendor back in the early 2000s made one and flew it at a launch I attended once. It flew just great with belching smoke and fire from the flame trough (okay, stovepipe with an elbow at the bottom end.)
I really enjoyed dealing with him. I wonder what he’s doing now.

 

[MidOH]

I don't think the Navy even launches them like that anymore. I heard it's all motor, right from the submerged sub now. "Missile doesn't even get wet.''

 

[Grog6]

After reading this last night, I woke up dreaming about a rocket launched from a potato cannon, with the engine lit by a pyrophoric mix of metals; I think Wile e coyote was helping. Strange dream...

 

[neil_w]

I think Mark Rober has made a silo launched rocket.

The linked video is by Joe Barnard, not Mark Rober.

 

[boatgeek]

I think that the only way that this would work with the barest modicum of safety* is to have a breakwire system that lights off the motor immediately after leaving the silo. You'd need some kind of relay system in line so that the breakwire disconnecting closes the motor's lighting circuit, plus a tiltometer or something to interrupt the firing circuit if the rocket isn't still pointed up. And a motor that lights instantly, reliably. And enough CO2 to really give that rocket a whack out of the silo. And probably more stuff to keep the altimeters from being fooled by that big whack of CO2.

I thought about just sealing the motor and lighting the motor underwater, but I don't see easy ways to keep from filling the rocket with water. There might be ways to do it with careful sealing and a plastic bag, but I'm not interested enough to try to figure out what that would look like.

* Probably not enough to convince an RSO at an organized launch, at least until you'd flown it on your own a few times

 

[Steve Shannon]

I think that the only way that this would work with the barest modicum of safety* is to have a breakwire system that lights off the motor immediately after leaving the silo. You'd need some kind of relay system in line so that the breakwire disconnecting closes the motor's lighting circuit, plus a tiltometer or something to interrupt the firing circuit if the rocket isn't still pointed up. And a motor that lights instantly, reliably. And enough CO2 to really give that rocket a whack out of the silo. And probably more stuff to keep the altimeters from being fooled by that big whack of CO2.

I thought about just sealing the motor and lighting the motor underwater, but I don't see easy ways to keep from filling the rocket with water. There might be ways to do it with careful sealing and a plastic bag, but I'm not interested enough to try to figure out what that would look like.

* Probably not enough to convince an RSO at an organized launch, at least until you'd flown it on your own a few times

An HPR rocket motor is sealed on the top end and wouldn’t fill with water unless it was inverted. Getting the nozzle wet should not affect ignition. I don’t think it would need additional sealing.
Using a timer like Missileworks for staging rather than anything barometric would allow a sealed av-bay. A sealed parachute compartment (vinyl tape?) should be easy enough. Sealing the interstage coupler might be just as easy. Quantum tube might be the perfect material for this.
I wouldn’t use co2; I’d just use a very high thrust short duration motor instead and treat it like a three stage with the first stage ignition underwater followed immediately by the second stage.
I might even cheat and put it on a rail.

 

[SkyFire]

When you get it built and launched, post a video, I'll be watching!

 

[PayLoad]

I don't think the OP was interested in the water aspect, but the bumping it off the ground and lighting mid-air. Which would be spectacular.

 

[COSTransplant]

An HPR rocket motor is sealed on the top end and wouldn’t fill with water unless it was inverted. Getting the nozzle wet should not affect ignition. I don’t think it would need additional sealing.
Using a timer like Missileworks for staging rather than anything barometric would allow a sealed av-bay. A sealed parachute compartment (vinyl tape?) should be easy enough. Sealing the interstage coupler might be just as easy. Quantum tube might be the perfect material for this.
I wouldn’t use co2; I’d just use a very high thrust short duration motor instead and treat it like a three stage with the first stage ignition underwater followed immediately by the second stage.
I might even cheat and put it on a rail.

"I’d just use a very high thrust short duration motor instead and treat it like a three stage with the first stage ignition underwater followed immediately by the second stage." Not a bad thought, but I'm still dreaming pondering the mechanics / physics of a cold launch.

 

[RocketPro]

The Mars Ascent Vehicle (MAV) under development will use a cold launch technique, called VECTOR. Check it out at: https://www.scientificamerican.com/article/the-first-rocket-launch-from-mars-will-start-in-midair/

 

[Steve Shannon]

"I’d just use a very high thrust short duration motor instead and treat it like a three stage with the first stage ignition underwater followed immediately by the second stage." Not a bad thought, but I'm still dreaming pondering the mechanics / physics of a cold launch.

It’s an interesting thought experiment. If I were RSO, I would prohibit blowing it out of a mortar tube or using a cold propellant motor to get it up off the ground and then air-starting a first stage motor at a low velocity without some kind of guidance.

 

[Budro0]

Stinger missiles use a similar ejection motor to get the missile out of the tube before igniting the main motor. Possible to start small to work out the kinks.

https://www.rocket.com/defense/tactical-missiles/stinger

 

[Initiator001]

I don't think the Navy even launches them like that anymore. I heard it's all motor, right from the submerged sub now. "Missile doesn't even get wet.''

The current Trident II D5 SLBMs are ejected from the launch tube of an Ohio-class submarine using a gas generator charge.
Once the missile breaks the surface of the water the first stage motor will ignite.