Parachute in nose cone

Has anyone done a dual deploy setup like this before? I am working on modifying my Minie-Magg for dual deploy with both the av-bay and the parachute in the nose cone. I put a 3" tube inside the nose, held in place by the bulkhead. A small av-bay will attached in the top of the 3" tube with an ejection canister pointing down. There are vent holes in both the nose cone and the 3" tube. The switch is installed in the side of the nose cone. The chute and recovery strap will be packed in the nose cone tube below the av-bav. It will use motor ejection at apogee then the altimeter will blow the chute out of the tube at 500 ft. I will put some tape across the opening to prevent the chute from falling out of the nose cone during ascent, and a chute protector to prevent the tape from sticking to the chute.

Done that with an 8" gizmo with a piston.

I saw this done on another thread somewhere using an ARRD. I have wanted to try this for a while now but you need a big enough nosecone. I used a similar configuration on a 4" nosecone, with the electronics in the nosecone, a C02 Peregrine ejection system and a shroud I made to hold the chute packed into a DP into, which was held in place with an ARRD and attached to a drogue/pilot on apogee.

GRIFFIN said:

Done that with an 8" gizmo with a piston.

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If this works well I was thinking about doing something similar with either an 8" Wildman Gizmo or Rocketry Warehouse Bruno for my next build.

Nathan said:

Has anyone done a dual deploy setup like this before? I am working on modifying my Minie-Magg for dual deploy with both the av-bay and the parachute in the nose cone.
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Click to expand...

Yes, I did as well, with my Estes Nike Smoke. I used this method for my Level 1.

I was thinking about something like this... Making a Velociraptor's AV bay in the nosecone instead of lengthening it in the traditional DD manner of the design.

If the vents are down near the center of the rocket, and the altimeter is in the nosecone, would that cause any problem with the altimeter?

Problem:
I flew the Minie-Magg at MDRA last Saturday. The parachute in the 3" diameter nose cone tube deployed prematurely at apogee motor ejection, instead of being deployed by the altimeter at 500 ft altitude.

Evaluation:
The method for preventing premature parachute deployment was blue painter's tape over the bottom end of the tube. Post-flight inspection showed that the altimeter had performed correctly. The ejection canister had fired and the charge was correctly wired to the main pyro terminal on the altimeter. Therefore the parachute deployment at apogee was not caused by the altimeter.

Root Cause:
The blue painter's tape failed to retain the parachute in the nose cone tube until deployment by the altimeter. Either the force of acceleration during ascent or the force of the motor ejection caused the parachute and recovery harness to dislodge the tape and come out of the tube.

Corrective Action Plan:
The aft end of the nose cone parachute tube will be modified and enclosed with an endcap consisting of a bulkhead and a short section of 3" coupler tubing. The endcap will be attached to the parachute tube with two 2-56 nylon shear pins.

Could also have been caused by too short a drogue shock cord. Had that happen to me once or twice. Longer drogue shock cord fixed it for me.

Man,,
You do some beautiful meticulous work / builds Nathan...
Good for you ....

Teddy