Estes 29mm Big Daddy mod question?

[Donnager]

I have installed a 29mm mount in an Estes Big daddy. Lower centering ring is now ply, fins are papered, etc. The MMT is about 200mm long.

Here's where it is different.

I used another tube that barely fits over the MMT. Checked distance, and set it in the nosecone. Drilled nosecone through the tube both directions, and threaded 1/16 ss wire through the end of the tube and the top of the weight. Poured full of glue to just above weight, allowing the excess to flow out the wire holes.

Kevlar line was tied to the stainless wire, prior to glue/epoxy.

Anyway, the idea is to NOT expose the parachute to a large charge. It will have barf/estes fire retardant in the MMT, but the parachute will not be exposed to hot gas until after the nose cone separates (in my mind).

Anyone done this and have any tips for potential problems?

 

[Nytrunner]

Dont melt your nosecone

 

[Donnager]

Dont melt your nosecone

I agree. It'll be hotter than average. There's about 3.5 oz of lead chips with a layer of glue between the tube and the plastic. Planning for dog barf or fire retardant fabric above the motor.

 

[T-Rex]

Seems like a lot of trouble for a problem that is easily solved with dog barf and/or nomex...... Although, you have probably solved the problem inherent to the Big Daddy. I don't think you will have to worry about your nosecone not coming off. I would recommend that you ground test it and make sure you have a long enough shock cord. I see that nose coming off with a lot of energy.....

 

[rharshberger]

Seems like a lot of trouble for a problem that is easily solved with dog barf and/or nomex...... Although, you have probably solved the problem inherent to the Big Daddy. I don't think you will have to worry about your nosecone not coming off. I would recommend that you ground test it and make sure you have a long enough shock cord. I see that nose coming off with a lot of energy.....

I would definitely ground test as the ejection charge will need to be lighter than normal since the nosecone is now basically a spigot style piston....

 

[Donnager]

Seems like a lot of trouble for a problem that is easily solved with dog barf and/or nomex...... Although, you have probably solved the problem inherent to the Big Daddy. I don't think you will have to worry about your nosecone not coming off. I would recommend that you ground test it and make sure you have a long enough shock cord. I see that nose coming off with a lot of energy.....

One benefit is the motor used can be very long, and doesn't change the recovery packing if the motor extends beyond the mount tube. Mostly I am just trying something different.

I am a little worried my shock cord isn't long enough.

I would definitely ground test as the ejection charge will need to be lighter than normal since the nosecone is now basically a spigot style piston....

Good point.

Definitely talked me into ground testing. Weather is bad this weekend, so will try to do that. If it does something interesting, I'll video and post it back.

Thanks for the feedback.

 

[Donnager]

For anyone interested, ground test worked fine, ejection was not violent, and shock cord was good.

I will, however need to either shorten the parachute leash, install a shroud on the bottom of the top tube, or use a small parachute blanket. When the nosecone left the top of the rocket, the ejection charge goes laterally when the outer tube clears, so if the parachute hasn't left yet, it will get burned.

Probably going to shorten the leash and add a blanket.

We'll see on the other Big Daddy I have.