NCR Build questions

[timster68]

I have an Estes NCR Big Brute and an Estes NCR Eliminator that I am going to start building and I have some questions about the parts.

Should I replace the Gorilla-Lock retainer ring with another one to hold the engine in place? I do have two NCR DarkStar motors for each which I want to use first, but I will want to be able to launch it again with motors that are available.

What kind of engines should I use after the DarkStars are gone?

Thanks for the help!

 

[rcktnut]

For my Big Brute I just added 2 threaded blind nut inserts and 2 screen clips for motor retention for motors ( reloads) that don't work with the Gorilla lock retainer.

 

[Oldschool77]

If I remember previous threads correctly, the darkstars are ~28.5 mm in dia. The motor tubes are sized as like. You will need to replace the motor tubes with 29mm tubes for the current lineup. That also means you will have to enlarge the ID of your centering rings for the new tubes. Also if your fins are TTW you may need to sand the tabs to fit.

 

[J Blatz]

Echoing Oldschool87, the MMT needs to be replaced with standard issue 29mm. When using the dark star motors you may need to build up their OD with tape.

My first big rocket was an NCR Phantom 4000 back in 1988.

Good luck with the build!

 

[Initiator001]

After I totaled my NCRBE Big Brute at NSL 2017 I pulled another one of these kits out of my dungeon and built it with a 29mm I.D motor tube one-half inch longer that the stock tube. This was so I could use one of the new Estes screw-on motor retainers. The original kit motor retainer will not fit the current AeroTech single-use/DMS molded motor thrust rings.

 

[timster68]

Ahhh, I was also trying to figure out if I needed to use a larger MMT for current motors. Thanks all for the help. I'm thinking I will need to use the thick wall 29mm Aerotech or equivalent for this.

I found the previous post about your build of the Big Brute with the 29mm MMT and that you were still using the Dark Star motors. So they would work - .5mm shouldn't make that much of a difference, but still you never know.

 

[rcktnut]

In my haste to post, forgot to mention replacing the mmt tube with a true 29mm one. Thanks Guys!!

 

[jd2cylman]

I got rid of the plastic centering rings on my Big Brute, and made mine a 38 mm mmt so I could use 38/120 motors. And bigger...

 

[timster68]

I got rid of the plastic centering rings on my Big Brute, and made mine a 38 mm mmt so I could use 38/120 motors. And bigger...

I am thinking of doing the same with my Big Brute now and with my Estes/NCR Eliminator so I can use them for my Level 1 certification. Is there anything I need to do besides trimming the fins to accommodate the 38MM motor mount and cutting the slots in the plywood rings? How did you cut the slots into the rings?

 

[jd2cylman]

I had some 3.9X38 CR's laying around. But If I was doing it now, I'd ask LOC to make you a set. Just tell them the fin thickness and they could laser you a set...

 

[timster68]

Wow ok. I didn’t know they did that. Thanks for the tip.