Cert 1 and 2: Jolly Logic Challenge

For those of you who are tired of Loc Goblins runaway now (dad joke of the day).
Since I'm not a millionaire and neither are my parents I am building what I think is the most cost effective rocket for both certifications.

Now John Beans the creator of the Jolly Logic Chute Release asked for the community to post all attempts for certification using his creation. So this thread is has started.

Goal 1: Build Loc Goblin
Goal 2: Fly Cert 1 on 29mm H182R
Goal 3: Study for Cert 2 test
Goal 4: Fly the Cert 2 using my 54mm gear
Goal 5: The journey to Certification 3

Goal 1: The build
From the far left of the body tube to the right is all standard Loc Goblin kit. From the fin side of the body tube to the left are the add-ons and 54mm motor gear.
Upgrades:
- 60" Ultra-X Parachute
- 18" Recon Recovery Nomex
- 30" Recon Recovery shock cord protector
- 54mm 1280 Aero Tech motor hardware
- 54mm motor adapter system

Blind nuts installed in motor retainers. I used JB weld for heat transfer purposes. Does it matter? Maybe, maybe not but it gave me a warm fuzzy.

Such a great rocket for your goal. Good luck with the build.

personally:
ditch their adapter system, and get a 54 - 38mm adapter from Aeropack. less weight, less fuss, use in other rockets....

And, what are you using for motor retention?

Going with the Loc z-clip system.

dr wogz said:

personally:
ditch their adapter system, and get a 54 - 38mm adapter from Aeropack. less weight, less fuss, use in other rockets....

And, what are you using for motor retention?

Click to expand...

Centering ring and eye bolt installed.

29mm setup with JB-weld.

Mocking up the MMA-system and mixing up the Rocket Poxy. Dyed it with neon yellow for fun. This is the first time using Rocket Poxy.

Dry fitting and then the moment of truth, rocket poxy the fin can together.

Excellent choice. I flew mine on a K motor to a little over 3k, so you should be fine.

You will get much better adhesion on laser cut parts if you sand the brown stuff off.

David Schwantz said:

You will get much better adhesion on laser cut parts if you sand the brown stuff off.

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All of the surfaces that were epoxied the lazer stuff was sanded off. I got lucky because I didn't know that, thank you.

I have some Bob Smith 30 min epoxy that I'm trying to use up and used it for the fin-can fillets. The Rocket Poxy that is seen is just squeeze out from fins being epoxied on.

Rail buttons installed and fin can sanded. If I have time I will install the fin-can tomorrow.

The really fun part is spreading that fincan by yourself over all four fins at once. Next time Ima gonna cut the slots all the way to the end, rather than just a slit in the center...

If you do it that way, save the little parts you cut out and glue them back in with CA, much easier to add a little bondo over them and sand.

Fin-can installed.
Things that work:
- use gloves (should go without saying)
- acetone to clean up drips
- isopropyl alcohol is hard to get due to Coronavirus
- have a dowel rod ready with a popsicle stick tapped on
- a flat head screwdriver helps put cardboard back in place behind the fins
- use Rocket Poxy; the stuff just stays where you put it

FlyBy01 said:

Rail buttons installed and fin can sanded. If I have time I will install the fin-can tomorrow. View attachment 408699

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curious as to how you installed the buttons..

dr wogz said:

curious as to how you installed the buttons..

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Yeah, I was wondering that too, seeing as mine are screwed into the centering rings. Maybe he used weld nuts. But 2 CR's would still have to pass by at least one button...

Ditto, I always aim for a CR, and I now always back up the button point with an extra layer of 1/4" plywood.. I find it easier to hit a hidden 1/2" area than a 1/4" area!

The rail buttons slide over the tee nuts and secure with the 6-32 screw.

I went to Lowes and bought Brad Tee Hole nuts in 6-32 thread.

Sanded the flat base for epoxy adhesion.

Drilled 1/8" in hole.

Used a q-tip to put CA on the area drilled to prevent cardboard separation.

Slowly increased hole size for nut, shaft to slide through.

Epoxied applied to nut base and inside the rocket.

I will post some photos tonight.

I think this is how Tim Van Milligan is doing his rail buttons. I'm not 100% but that's where the idea came from.

I came up with this solution as a work around to make the rail buttons replaceable. Also I needed a flush type solution for the fin-can to slide past.

Loc Precision directions say in a nut shell drill an undersized hole, put epoxy on the screw, screw the buttons in place, and place the buttons toward the ground to allow epoxy to flow with gravity.

Please post if there is a better way to do things I'm here to learn. I'm Tripoli Cert level 0 working towards Cert 1 and beyond.

Glue t-nuts in place inside the airframe (in conjunction with the fin can, at least on the lower position). Then you have full serviceability of the rail buttons. I usually just flip them over and put a fillet of epoxy around and over the flange.

Mr. Flyboy,

go here, post #6 for the idea of adding a backer to the CRs where you intend to put a button
https://www.rocketryforum.com/threads/madcow-super-dx3-patriot-a-build-thread.140215/#post-1693819

(Yes, a shameless plug! )

What a few of us do, is put our button on with wood screws, typically a #4 or #6 x 1/2". We aim for the middle of a CR. Since blindly aiming for a 1/4" is hard, aiming your drill into a 1/2" is easier. the button can then be replaced with a new one, and a new screw. It's also going into some structure, rather than a glued-in face on the inside of the tube which some say isn't as strong. (not that this really is an issue..) We know where the CRs are going to be in the tube, as we've planned a head. I mark my tube with the place were I expect the thickened CRs are going to be, and I assemble & such. I drill my pilot holes once the MMT is installed. Some would argue, that you are adding more unneeded material (metal) to the rocket, and this will rob you of a foot or two altitude!

The way you did it, I assume you needed to sand a bit of a flat on the CRs to clear the back of the T-nuts. This method is not uncommon for buttons higher up on the tube,m or where there is uncertainty to where the upper CR is, exactly..

https://www.rocketryforum.com/threads/another-loc-goblin.148378/

some inspiration for you..

While it has flown a few times, it did suffer a crash: the body collapsed the chute as it deployed. So I have a fin to repair..

https://www.rocketryforum.com/threads/4-loc-goblin.148895/

some more.. you can compare your build with this one..


or this one:
https://www.rocketryforum.com/threads/loc-goblin-thread.145083/

Enjoy the build! enjoy the flights! (I miss mine!)

Rubber well nuts (aka Rawl nut) work too, simply drill proper size hole in airframe, if its cardboard, harden with CA and insert rubber expansion nut, with screw and railbutton and tighten until unable to pull it out, easy.

rharshberger said:

Rubber well nuts (aka Rawl nut) work too, simply drill proper size hole in airframe, if its cardboard, harden with CA and insert rubber expansion nut, with screw and railbutton and tighten until unable to pull it out, easy.View attachment 408903

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Good option. I use these especially on rebuilds and updates where you are replacing launch lugs and thus don't have access to the inside of the airframe.

Pics as promised

Speaknoevil said:

Glue t-nuts in place inside the airframe (in conjunction with the fin can, at least on the lower position). Then you have full serviceability of the rail buttons. I usually just flip them over and put a fillet of epoxy around and over the flange.

Click to expand...

I used these instead so I didn’t have to worry about the prongs.