L2 cert rocket

[Sooner Boomer]

I said I'd post pictures when I got the rocket in primer. Just sprayed 2nd coat. So here it is...



Open Rocket says that (with the data I entered) the rocket should reach ~6400 feet, and reach mach 1.36. This is the biggest, heaviest, most powerful rocket I've built to date. Here's how it went together.

The parts:


54mm LOC body tube, 38mm motor tube, centering rings, and nose cone. Also shown is a PML 29mm motor tube. I originally thought I would build it with a 38mm hole and use a reducer to fly on "lesser" motors. Then I decided not to (one reason being the amount of force the engine would place on the adapter). I have both a PML and LOC nosecone. Will probavly use the PML because it's already prepped.




The recovery harness is attached very securely to the motor mount. It was initally tacked down with a drop of CA. I then saturated the kevlar tape with Titebond and wrapped it with nylon cord, which was also saturated in glue. This also serves ro reenforce the top of the motor mount.




I carefully drew the fin outline of a piece of heave card, transfered the outline to some 1/8" ply, and roughly cut the shapes out. I aligned the fins and bolted them together. A little work on the belt sander got them to their final shape.




The fin tabs were sanded to correct length for the individual slots in the body tube. Notice the number on the fin and the dots next to the slot. The fins were tacked in place with a bit of CA. The hole in the body tube is where the rail button will go.




Epoxy fillets at fin roots. While the glue is still soft, I shape it and cut boo-boos off with a sharp woodworking chisel.




MOTOR GOES HERE. this is the aft end with the fins set (but no fin fillets yet). I used my scales and put 10 grams of mixed epoxy on each side of the fin/motor tube joint. They are very solid.




This looks like a mess! Motor retainers were glued in with JB Weld. They are 1/4" hex standoffs, 1" long, threaded 4-40. I stuffed paper towel dams down the insides, and added more epoxy.




The two body tubes were glued together with Gorilla Glue and hung up to "dry". I did it this way to keep from getting glue all over the recovery harness.




And here it is in primer. I'll sand it a bit more, and *might* spray it either blue or black. That's just for the first flight. I'll probably change it later (after doing a better job of filling/sanding).

The plans are to launch it Saturday at Sayre on a J270. I have a borrowed radio tracker, a ribbon drogue, a screamer, and a JLCR opening a 30" chute at 400'.

 

[Homer_S]

That picture of your motor mount reminds me of this:

Homer

 

[Five]

I need to decide on a kit to buy for L2 certification at October Fest. Its right around the corner.

 

[Sooner Boomer]

I need to decide on a kit to buy for L2 certification at October Fest. Its right around the corner.

Or you could scratch build.

 

[boatgeek]

Looks like a nice solid bird. I like how you whipped the kevlar recovery harness to the motor mount. Good luck on your cert flight!

 

[Sooner Boomer]

The Good, The Bad, and The Ugly... (not necessarily in that order)

I've been building rockets for a long time now. Apparently, I still have things to learn. I made several "mistakes" designing the rocket in my head. I thought I would make the fin attachment very strong by using basswood strips to form a "pocket" for the fin tabs to sit in. I didn't take into consideration the fact that the strips are square, and I was trying to fit them onto a curved tube. I wanted to use a ribbon drogue, but when the rocket was packed with a borrowed tracking beacon, the drogue didn't fit. And so on. Nothing big, just had to adapt the game plan as I went.

Used a JLCR for the chute. Due to some last minute adjustments I had to make, apparently I didn't attach it to the rocket. It worked perfectly, but it's now lost.

Great flight on the way up. Motor turned on like a switch. Good ejection (event by sound). Looked for over an hour in 90+ degree heat. We'd given up and were driving back to the pad when someone saw it in a field. NOT the field the tracker had indicated. The tracker had indicated a field to the East of the launch site. We found it in a field to the North.





Cert form was signed, and will go into the mail Monday.

Thanks again to everyone at Tripoli Oklahoma that helped me, gave advice, and motivated me.

 

[Jmhepworth]

Cert form was signed, and will go into the mail Monday.

Scan and email. You’ll get it faster. Deb will like you more.

 

[Sooner Boomer]

Scan and email. You’ll get it faster. Deb will like you more.

Done!