My L2 project

[Jase]

Here's the outline of my L2 bird.

I saw DG&A Rocketry's website and really fell in love with their Armageddon rocket. I can't afford $150 for a rocket so I decided I could build it myself for a whole lot less.

Mine will be a little smaller than the original, but that's ok.

I have a 54.5" long 3" ID tube for the main body with a 15" long tube for the payload section. I plan on using 1/2" sign plywood for the CR's, bulkhead, fins and canards for lots of weight. I also have a couple of PML 3" couplers laying around. About the only part I'll have to buy is a PML 3" nosecone and 38mm tubing (which I bought at Whitakers in June) and some various hardware.

I want the weight on it since I don't plan on using any electronics or dual deployment and want to keep the altitude between 2000 and 2500 ft.

Here's the Rocksim file I've created for it. Thanks Milo and Rstaff for letting us attach .rkt files now!

I'll keep ya'll posted on the progress!

 

[rstaff3]

First, thank Milo for the .rkt uploads, he did all the real work!

and....your design looks great! Can't wait to see it progress.

 

[Milo]

Real work? It took all of 30 seconds!

 

[rstaff3]

Ha! Then I retract my previous statement and claim most of the credit!

Thinking of the idea - 263ms.
Posting the messages - 10 sec total
Finding the original image ~ 60 sec.
Editing it the first time ~ 300 sec.
Editing it the second time ~ 600sec.

 

[Jase]

I went to work today so I could use some tools. I spent the afternoon cutting out the bulkhead plate, centering rings, fins and canards out of the 1/2" vinyl covered plywood that we use to make signs out of.

I'm trying to get this thing to weigh between 10-12lbs. to keep it in the same county when it comes down.

Here's the first couple of pics!

More to come!

 

[KermieD]

Vinyl covered ply? Sounds like someone's cheating and saving a sanding step! Looking at the parts list you have, I don't see the boattail fins from the main body tube to the motor mount tube. When you first mentioned cloning the Armageddon, I took a look and downloaded the rsim file, thinking I'd do the same. I noticed those fins to the MMT and went "screw that!!" Are you skipping those (personally, I would)? Either way, I LOVE the looks of that rocket!

 

[rstaff3]

Now that's my kind of rocket! The components look nice...the vinyl covered plywood sounds like just the thing for me...no sanding...

Make sure you check the size of the chute, you are just at the point a 60" chute may not be enough. Of course, 1/2" plywood is pretty tough!

 

[Jase]

I didn't even see those until I was reading some of the reviews on EMRR about the Armaggedon.

I contemplated cloning those as well, but couldn't figure out what they were made out of and how they were attached.

While it helps with the overall look of the bird, I decided for mine, it would be a possible break point that I didn't want to mess with. Not to mention, a motor retention nightmare.

And since mine is only 3" diameter anyway, the spars would have to be very short. So, I am leaving off the boattail spars.

As for the no sanding step, think again. I'll still have to sand it pretty good for paint to adhere.

I am debating on how to treat the leading edges on the 1/2 ply. I was thinking some big time airfoils, but this ply tends to shred as you get into it (it's only 3 ply). I'm leaning now toward just rounding the edges.

Any suggestions?

And the chute size at this point is still up in the air. I agree that a 60" chute may not be enough.

 

[Austin]

Looks great Jason...man you better get a building...for a 12-14lb vird though, I would up the motor mount to a 54mm...

Carl

 

[Jase]

You're right Carl. After redoing some of the component weights, it's probly going to be right around 11 lbs or so.

It's simming out currently on a J360 to about 2200' which is right about where I want it.

 

[rstaff3]

Actually putting in the bigger mount is a good idea - you can always make a 38mm adapter. I put a 3" main mount in my L2 rocket, but unfortunately have only used 38mm motors...I keep dreaming about a 3" K....

 

[KenParker]

Jase - here's an idea for your leading and trailing edges. At King R/C or at K/C Hobby in Archdale (probably your preference since it is much nearer to you) you can get shaped balsa pieces that you could glue onto the leading and trailing edges. You could get rounded half inch for the leading edges, and triangular half inch for the trailing edges.

There are a couple of ways you could seal the balsa. You could put CA on the balsa and then take tracing paper and wrap it around the pieces and overlapping it about a half inch onto the vinyl.

Actually, just soaking the balsa with CA and sanding would definitely seal and harden the pieces.

Or, you could use West Systems epoxy and 2 oz fiberglass, again overlapping about a half inch onto the vinyl.

Or, you could just load the balsa up with primer and sand, sand, sand.....

Just a thought.

Looks like it will be a cool rocket, dude.

 

[eugenefl]

Jase, it looks like a good start. I've never seen that kit before. I must say you sure picked a good rocket to clone! I think we'll all thoroughly enjoy watching it come together.

I noticed your 38mm MMT tube. It looks really long. Will it be necessary to use the entire length for the motor ejection? I understand you don't want a huge area for the ejection charge to get lost in, but that sure looks like overkill. I'm just curious if there is a standard max volume for safe motor ejection or if its something you play be ear, err, by eye.

 

[Jase]

Thanks Eugene.

The first pic shows the whole 38mm tube. It was 34" long. I've already cut it down to 24". As I recall, the 6 grain Pro38 casing is about 18" or so long. So it'll leave me 6" or so of motor tubing.

I'm pretty sure it'll be ok. If it's not, I hope somebody that knows better will speak up!

 

[KermieD]

Sorry 'bout bringing up the spars. I honestly had thought that for level 2 I would have to go with dual deployment, but now you have me really thinking about just building something heavy enough to do it without.

I agree that the Armageddon is a great looking bird, and I'm jealous that ya beat me to it!

 

[Jase]

It's coming along.

I got the shock cord (about 28' long) epoxied onto the motor tube along with the forward and fin leading centering rings.

Also started the bulkhead coupler. After the epoxy on the U-bolt hardens, I'll epoxy the plate into the coupler tube and glaze it for max strength and flame and water resistance (which hopefully, I'll never need).

Also got the 1/2" x 13.5" fin slots cut in the main body tube. 4 1/2" slots take a lot out of a 3" diameter tube. I plan on filling the fin tab section with PML's expanding foam to help stiffen that section up.

And I couldn't resist. I did a dry fit on the fins.

Here's the pics

 

[rstaff3]

Dems some nice lookin' fin's!

 

[eugenefl]

Have you ever had an itch that no matter how hard you scratch only itches more? No matter how hard you try and ignore it, the urge only worsens.

Damn you Jase for building a scratchbuilt rocket!

I'm getting an itch!

I guess maybe this is why we all love pictures so much. It only spreads the urge. Ok, I don't know what got into me. Totally off topic.

It's lookin' good. I'm anticipating the post where you curse the hairy shipping tube.

 

[Jase]

Mwahahahaha...

All part of my evil scheme...

The hairy shipping tube will come soon enough

I'm currently holding the bulkhead assembly waiting anxiously for the 15 min. epoxy to set. Makes typing a beotch!!

 

[rstaff3]

Ahhhh, there is nothing like scratching that ITCH with a SCRATCHbuilt rocket!

New rocket saying: Keep the gooey end up and the epoxy outta your keyboard!

 

[PGerringer]

LOL, Go Jase Go!!!!

You keep this up and you will be L2 before Ken, Mark and I are L3.

 

[Jase]

Last night, I assembled the bulkhead, tacked the canard fins to the 15" payload tube with CyA. I will be applying generous amounts of epoxy when I get some more, and tacked in the motor mount to the main body tube.

This afternoon while waiting for the plumber to show up for 3.5 hours, I got to pour a bunch of epoxy. I glazed the forward centering ring inside the body tube (it ain't goin nowhere now) and both sides of the bulkhead plate.

Pics here

I should have enough epoxy left to attach the bulkhead assembly to the payload section tonight.

I may also get the fins tacked in place as well. I know I don't have enough epoxy to get those attached well right now.

Gotta go shopping this weekend.

:wondering how many times Carl has fallen out of his chair reading that I let myself run out of epoxy:

more to follow