Non-Conventional parachute ejection/deployment ideas needed

Hello all, have not posted in a while. Still read regularly.


Im working a LPR rocket that cannot blow the nose cone for parachute recovery.
I am looking for ideas for alternate parachute ejection.

I also cannot do the conventional rear "pod" ejection.

As of now I am designing a side ejection which seems a little cumbersome.
Rocket diameter is about 5 inches.
Side ejection gives me about 2 inches to pack a 30"chute, shock cord and leader which comes out the middle of the nose cone.

If someone could direct me in the right direction-

Much appreciated!!!!
Cornyl

How come the nose cannot come off? Could it shift? I could envision a few different ways of exposing an opening or venting the gasses with a curved chamber, but it is a little hard to get to specifics without more of your design.

Ditto that. If your rocket "cannot blow the nose cone," then it is not a conventional rocket, and we would need to see it and understand it before being able to help.

5" diameter and 30" chute? Both sound a bit big for LPR. As #5 would say: "Need Input". Tell us more about what you're trying to do.
-Ken

Thanks, for your input.
I will post a pic.
Pretty much it is a 5" oatmeal type container-cyclinder, nose cone glued on, tubular fins
D-12-3 engine.
Nose cone has hole drilled at top of cone center. Carpet thread anchored to inside of rocket , carpet thread runs through nc down side of rocket into a side
ejection trap door which has the shock cord and parachute.
The trap door is mounted on a horizontal tube which connects to a vertical tube down to the engine, imagine tubes in the shape of a T mounted inside the 5 inch tube, and the ejection comes out one side or the T.

The reason for side ejection is I did not want to create a 5" shoulder for the nose cone to slip into the tube.
I guess I could have used centering rings on the nose cone and use a small diameter tube to eject.-Just did not want to do that. Nose cone is hollow.
will post pic soon.
Thanks Cornyl

rotor?

cornyl said:

Thanks, for your input.
I will post a pic.
Pretty much it is a 5" oatmeal type container-cyclinder, nose cone glued on, tubular fins
D-12-3 engine.
Nose cone has hole drilled at top of cone center. Carpet thread anchored to inside of rocket , carpet thread runs through nc down side of rocket into a side
ejection trap door which has the shock cord and parachute.
The trap door is mounted on a horizontal tube which connects to a vertical tube down to the engine, imagine tubes in the shape of a T mounted inside the 5 inch tube, and the ejection comes out one side or the T.

The reason for side ejection is I did not want to create a 5" shoulder for the nose cone to slip into the tube.
I guess I could have used centering rings on the nose cone and use a small diameter tube to eject.-Just did not want to do that. Nose cone is hollow.
will post pic soon.
Thanks Cornyl

Click to expand...

All this just because you didn't want to "create a ... shoulder"???

{semi-grouchy curmudgeon response emminent...}

Cornyl, I learned a particularly sage bit of advice about design far too long after graduating from Architectural school at Auburn, but still quite a few years ago - such that I *have* benefited from it --- and it clearly seems applicable here:

"If solving one problem simultaneously solves another problem (or two), you know you are on the right track."

The corollary to that is:

"If solving one problem simultaneously creates two more, you *know* you are heading down the wrong track."

Recovery is an area that is fraught with danger and pitfalls -- without extensive experience and a LOT of testing, research, study and tears, it is NOT a place to 'get creative' (as much as I genuinely love creative solutions). As I've always said, "As concerns recovery, Murphy was an optimist."

Frankly, I would take that 'sage' advice noted above and rethink your design - because surely not wanting to 'create a ... shoulder' hardly qualifies as a good reason to complicate this recovery to the degree that is going on here.

YMMV (but I bet it won't be by much).

{/semi-grouchy curmudgeon response}

-- john.

Where did you get a nose cone with no shoulder? Is it one that us supposed to use a coupler, and you don't have a coupler?

Rear ejection.

I built a rocket with the NC glued in due to the motors being mounted at the base of the NC. I used rear ejection. I am doing another one right now with rear eject. It works. See the post below for more info, then contact me if you have more questions.

https://www.rocketryforum.com/showthread.php?67272-Estes-V2-Steam-Punk-Forward-Mounted-Canted-Cluster-build-thread

With a 5" diameter oatmeal container body you should have NO trouble at all creating a Rear Ejection system with a couple custom make centering rings of something as thin as the cardboard from the back of a Lined Paper pad. I've used this method on a number of Odd-Rocs with great success. If you using a single D12 you have plenty of room between the rings to roll/pak your 30" chute.

I also agree with jcato that Side mounted ejection systens are often very difficult to make work porperly and consistantly. The more complex the design the more likely it will fail on it's first or second flight. Is that worth the time spent buiding such a unusual recovery system, trying to work around a simple thing like making a nose cone shoulder? It really is Not!
another old adage that seems particually approperate to this thread is "Think before you Act". Safety first alway when it comes to building and flying Model rockets...particularly ODD-Rocs.

Last night, I was at a club meeting. The topic: Mechanical deployment out of a side panel. The team had built, but yet flown, a 4" rocket that would deploy a chute out the side w/o any black powder, pyrogen, CO2 or any other energy source other than a spring which was just a little bit bigger than the kind on ball point pens. When I saw it, it reminded me of this thread. Needless to say, it was a complex system. But the guys were doing just as much for the engineering challenge as they were to solve a real problem (hassle of using BP).