My L3 Build

[FlyBy01]

RunCam6 mount that will eventually be used. I had printed this version for someone, so mine will probably be in PET-CF with a layer of HTR-212 epoxy then painting.

View attachment 653430

Can you please share the stl file.

 

[thzero]

Prepping the altimeter bay for the switch band.

 

[FlyBy01]

A random tool! This was a 3d printed end for a 1/4" aluminum rod that I can attach sandpaper too. It was used for sanding all the interior surfaces my arms wouldn't reach to! Was used more in my 4" build just because of the smaller diameter, 5" allowed me to shove more of my arm into it.

View attachment 651570

Another tool. Squaring jig. Didn't have a shot of 5" version, so this is 4" version. It worked ok. But it worked better when combined with the wrapping a stiff piece of paper around the tube method. Now things mate flush!

View attachment 651571

Is this your design or is there an OpenScad I need to add to the collection.

 

[thzero]

Is this your design or is there an OpenScad I need to add to the collection.

Yeah, my design too

https://cults3d.com/en/3d-model/game/rocket-tube-squaring-tool

I do most of my CAD in OnShape; in this case really should have created a OpenScad version because its pretty simple shapes.

 

[thzero]

The tool after some use! Tape was to give it a good fit.



Came out quite nice.



And the final product with the 1/4"-20 stainless steel bolts that, addition to epoxy, secure the switch band onto the coupler.




Now just gotta finish the nose cone, the main parachute bay, and tweak the electronics.

 

[thzero]

Made some more progress...

The centering ring that will be epoxied onto the coupler, before the coupler is epoxied into the nose cone. Used 1/4"-20 PEM nuts (https://www.mcmaster.com/catalog/130/3661/94648A370 for reference). Centering rings were scuffed, cleaned up, then wiped with Acetone.



The PEM nut had grooves cut on the sides first, then roughed up with sandpaper. Cleaned them off, then wiped them down with Acetone.



Then applied some epoxy around the ridges. Then it was just a matter of placing it into correct sized hole, threading a bolt onto it and pull it tight. I wiped off any excess epoxy to make sure that the PEM nut was flush and fully seated. Then applied the generous filet of JB Weld around it.




Add the u-bolt to the nose cone bulkhead that bolts into the above centering ring. As always, bit of red Loctite first, then JBWeld.

 

[thzero]

The parts for the shock chord attachment.



Got the U-bolt installed as I did above in the stepped bulkhead that forms the

 

[thzero]

Well, the tracker stack is done so that it slides into the nosecone.




Now to epoxy it into the nose cone. Well once I unbolt the tracker bay!

 

[thzero]

Ok, so guess between coating the coupler and inside of the nose cone as thing as I could and scraping epoxy to just leave a thing layer - obviously not thin enough.



...still had some drippage, which is why the tape! Makes it fairly easy to clean up.

Then after it had set and cured... I just had to see what the entire stack is starting to look like. Meet my little friend...

 

[thzero]

Well, got all the rail buttons sorted and attached. Then got the booster's shock chord attachment mounted sorted and drilled and the nuts attached.

 

[thzero]

Think I showed this before, but this is the shock chord attachment cannister. 1/4 bolts using press-fit nuts (for soft metals and plastics) that are then epoxied with JB weld. The nuts had shallow grooves dremel'd on the outside to give some more area to grip as I did in this post.




Ok, I did a terrible job at making things clean, and also aligning the bolts and the u-bolt. Oh well, doesn't matter that much.



Attached into the rocket with 1/4" stainless steel hierarchy.



Add seeing it from the top of the booster. Plenty of room for both the shock chord and drogue, as well as a N2000 (oiy!).

 

[thzero]

Got the altimeter bay's bulkheads completed with some test ejection cannisters. The black pieces are some rubberized plastic that fit over the thumb screws quite nicely and make sure there is no contacts between the quick link and the ejection wire rods.



And the backside. All the bolts have some gaskets cut for them.

 

[thzero]

So we are pretty much done...

Avbay...





Then some pics of the interchangeable camera mounts.



Hi temp silicon as padding and to keep the plastic from marring any finish.

 

[thzero]

Well, booster is completed... not the best paint job, but it'll work...

 

[thzero]

On the rail at Midwest Power...

 

[ECayemberg]

On the rail at Midwest Power...

View attachment 676494

Great flight, Chris!!! Happy I was able to be at the pad with you preflight! Congrats on a job well done!!!

 

[thzero]

Great flight, Chris!!! Happy I was able to be at the pad with you preflight! Congrats on a job well done!!!

Thanks Eric, appreciate it!

Bunch of thanks to others too - from my local club Brian J, and Don K. Don K was helpful in tracking down the rocket since had a bit of 'fun' with that. Had lost visual sight of it, and a few others had too. Although talking to Chuck later said he saw it under chute to the south, after we had recovered it.

With Don's help, we headed south of the site stopping to let the Featherweight orient itself. Then based on that headed west along the road south of the site and ran across someone coming back from finding rockets, Mark G. Anyways, he asked if we were looking for a red/white rocket, and with help of his binoculars sure enough there it was laying in the next field south about 600' off the roadway.

Got the data off the tracker and the altimeters.
Featherweight GPS had it at 7,894' with a max velocity of 788 f/s.
Primary Eggtimer Quantum had it at 7,763' with a max velocity of 872 f/s.
Second Eggtimer Quantum had it at 7,758' with a max velocity of 868 f/s.

Drogue altitude was 7716', and main was at 971' per primary.

Trace from Featherweight app shows an interesting trace; the sharp angle is most likely where the main came out.

 

[thzero]

Some pics from the landing site...












And some of the shots as I undid the altimeter bay and cleaning it up.

 

[thzero]

Flight info...




Google Earth flight path...

 

[thzero]

At least the up-part.... and I almost screwed that up fiddling with the phone.

And link to the L3 package.

 

[thzero]

Video...

 

[Theory]

GREAT JOB!!!

what was the all up weight on the pad? know you did a fair amount to keep the weight down.

 

[thzero]

GREAT JOB!!!

what was the all up weight on the pad? know you did a fair amount to keep the weight down.

Thanks. It was 37.4lbs all in.

 

[Theory]

cool, thank you!

 

[Dave S.]

Grade school tool for marking filet lines on the rocket. Rub some graphite from a pencil on a piece of paper, use your filet tool of choice and....

View attachment 651753

Lines... Faint but they work. Even on the black fiberglass fins it was enough that the graphite would reflect that I could see where the marks were.

View attachment 651754

I use old-school carbon paper. It was tough to find some, so I got it from Amazon or eBay.

 

[cwbullet]

I use old-school carbon paper. It was tough to find some, so I got it from Amazon or eBay.

I have 200+ sheets - I got a great deal at Office Depot in their clearance.

 

[cwbullet]

@thzero
Congrats on your success.

 

[kjhambrick]

Congrats @thzero

Very nice flight and a great build thread !

Thank you.

-- kjh

 

[thzero]

Congrats @thzero

Very nice flight and a great build thread !

Thank you.

-- kjh

Thanks! Was quite exciting!