PDA

View Full Version : BOOM! CJ's Wildman3 rebuild after L-2300 CATO



blackjack2564
14th September 2010, 08:04 PM
At Argonia I flew [or attempted to] in a drag race my Wildman 3 inch on a KBA by AT L-2300 green.

Right at burn out, about 1000ft up....Ka-Boom..... the front closure shot through the airframe and vaporized the interior of the rocket.

Altimeters [r-das & Missleworks mini....gone, Tracker which is in foam in the NC gone. Blew the motor and Areo-pac right off the MM tube and out the back.
Chute shredded.
Just the flared end of the motor case held it in.

The picture shows just how I picked things up.

blackjack2564
14th September 2010, 08:12 PM
After removing the thrust ring The motor was pounded out the front of the rocket. The CR's had it wedged and could not go out the back.

For what ever reason, the motor seems to have over pressurized right at burn out. A 1inch chunk of motor case let go right above the snap ring and the motor is flared all around below where the ring was.

There was nothing left inside the case except the nozzle and rear ring.
Liner, grain, casting tube, front closure & snap ring vaporized.

I know of 2 other similar problems with the L-2300, if you have had any please let me know. The other one in the race flew just fine.

blackjack2564
14th September 2010, 08:28 PM
Now for the GOOD news, It's a Wildman rocket and it survived! I can fix it.

As far as the CATO, some one once said, If you can't stand a problem now and then with rockets.......go buy a train set.

Basically all I need is a set of bulkplates for the AV-bay and hardware, and a new nose cone, finally trim a couple inches of the zippered fincan and glue the retainer back on.

Not too many rockets that I know of could have survived this!

The NC was split right in 2 and the foam just disappeared when the closure shot through it.
I though about rebuilding it, but it was just too much work , even for me.
I would have had to remove all the remaining foam residue before I could glass it.

troj
14th September 2010, 08:54 PM
What day did this happen on, Jim? I don't remember it....

Maybe I was out in carnage recovery mode.

-Kevin

blackjack2564
14th September 2010, 10:09 PM
It was sat late afternoon. I was Drag racing Darryl [wildman Kentucky] when it happened.

Anyhow the fincan only has a small zipper and popped off the cosmetic bondo over the fillet. After I post all the damage the rebuild will start.

More proof just how sturdy injected fillets are !

G2Rockets
14th September 2010, 10:18 PM
Jim,
I look forward to watching the re-build.

John

Johnly
14th September 2010, 11:35 PM
I have one these reloads waiting to be used. What was the date code on the reload kit?

BTW.... I haven't seen a MESS report for any failures of the L2300 motor reload. It sure would be handy if people would submit this information so that if a problem can be shown to present, we can reduce the carnage suffered by other fliers.

John Lyngdal
NAR Standards & Testng

troj
14th September 2010, 11:37 PM
It was sat late afternoon. I was Drag racing Darryl [wildman Kentucky] when it happened.

Yep, I was on carnage duty.

Bummer it happened; makes for a wonderfully educational thread for us, but it sucks bigtime for you.


Anyhow the fincan only has a small zipper and popped off the cosmetic bondo over the fillet. After I post all the damage the rebuild will start.

More proof just how sturdy injected fillets are !

Excellent!

-Kevin

GaryT
14th September 2010, 11:51 PM
Jim:
Sorry to see the mishap, Glad it can repaired though. I have a KBA L2300G as well so I hope your's was just a fluke.

SSenesy
15th September 2010, 01:32 AM
Jim;

Only you could turn this much carnage into something that'll probably fly better than the original.

Looking forward to a rematch drag race at RG :cool:

blackjack2564
15th September 2010, 04:26 AM
I'll find the instuctions with the code and post it tomorrow........

..... First thing to do was dremel off the Aero-pac cap so I can remove the motor. The base was fine, cap distorted due to being blasted off the MM tube.

blackjack2564
15th September 2010, 04:34 AM
Then with a wire brush and some elbow grease, remove the JB weld residue from the rings, so I can re-attach it.

Cleaned up the MM tube with sandpaper, mix some fresh JB and re-glue the base on. There was NO damage to the mm tube!

blackjack2564
15th September 2010, 04:42 AM
This has always been my "go to" rocket & thus has been flown and beat up pretty bad. 2 lawn darts and 3 flat spins in with no chute[for various reasons] had taken it's toll on the paint job.
Figured I might as well give the old bird a fresh coat of paint while I was at it so I sanded most of the old off.

Had some left over JB from the retainer glue job and used the remains to re-do the fillet. [only the one side had any damage] I would normally use West but why waste the JB.

Pantherjon
15th September 2010, 02:43 PM
Amazing how much carnage a little piece weighing, what 6oz(if that!), can do!:eyepop:

CJ the Rocket Build/Re-Build Guru! ;)

blackjack2564
15th September 2010, 10:29 PM
Paperwork as promised with batch code. Am I reading this right: Aug 5 2009 batch 3 ?

blackjack2564
15th September 2010, 10:36 PM
On to the fincan: Here is all I had left of my 2 Av-bay allthread, pretzel time!

Cut about 2 inches of zipper off with a chop saw. [Miter saw]

Then used the old Estes wrap paper around the tube to sand and true up the edge.

You can see the before and after gap & tight fit of the joint attained from this simple process.

JDcluster
16th September 2010, 03:23 AM
What did the liner look like before the flight? I remember one of the problems being a liner issue....

One other possibility: It could have also been a snap ring issue.


JD

blackjack2564
17th September 2010, 07:14 AM
What did the liner look like before the flight? I remember one of the problems being a liner issue....

One other possibility: It could have also been a snap ring issue.


JD
Don't quite know what you mean..... liner looked like a typical new KBA liner. What issue are you referring to?

Snap rings were checked as usual, only the second time used and the sharp face was facing out on both ends, rounded in. They were firmly seated and double checked by a fellow flier as I always do.


BUT:

As I mentioned earlier the casing was clean, only the nozzle and snap ring remained. No charring the interior was shiny liked you just cleaned the case It was obviously near or at burn out, The only thing to come out was the full size smoke grain and front closure and liner. No lit grains or we would have seen green flames. Only white from the smoke grain could be seen.

There was no charring or burnt interior of the rocket. The case is well flared as can be seen in the photo as well as the 1 inch chunk that blew off right at the snap ring groove. It was a brand new nozzle and checked with a gauge to make double sure it was the correct size. The case had 16 or more flights on it and maybe it was just it's time. Really....how long do they last anyway?

I received a phone call from a propulsion expert [manufacturer] after he read my post and after a lengthy discussion & many questions, this plausible explanation could be the culprit.

Barium component in the L-2300 is very hydroscopic . This load was opened and loaded last April. I live in Savannah where humidity is EXTREME. Even though I wrapped the nozzle end in plastic and taped it to the case, apparently moisture can permeate. I have done this before, having loaded motors for over a year without any issues, but they were never green.

This then can cause the propellant to de-bond from the casting tube,causing an over pressurization due to more surface area burning.

Of course there may have been other factors. Really.....don't think we'll ever know FOR sure. It's a rocket motor and things can and do go wrong. I did check it before it flew and there were signs of grain sweating, so I left it open for 24 hrs before flying. Maybe not long enough.

One of the other 2 catos I'm aware of....... the load had also been left open for a lengthily period, but THIS was done by an AT representative and nothing was said about this going to be a problem. [Parts were needed and removed for whatever reason]

As I said before.....I'm not crying over spilt milk or upset in any way. We fly rockets and every now and then something bad will happen...just part of it.
Some of these new motors are on the edge and flying them is a risk we take. As far as I know this is the only L [680lbs of thrust at peak]for this case, so that tells you something right there. I chose to fly it, I took the risk, I suffered the consequences. So be it! Wouldn't have it any other way. I fly way more than the average rocketeer and the law of averages just caught up to me.

At least the rocket survived, truly amazing in it's own right!

blackjack2564
17th September 2010, 07:19 AM
Well I finished removing most of the old paint, sanded and primed the bird. Very little cosmetic filling was needed, only where I doctored up the 1 fillet.

A new nose cone was procured and the Wildman was taped off for it's signature orange and blue finish.

Finally I sprayed the florescent red/orange. Metallic blue tomorrow as well as clear.

This is the 3rd rebuild and it's quite a bit shorter than when new back in 2004, but I can still get a 6 grain K in it! She's flown to 15,300 on a K-250 in the past, not bad for a big clunky 3 in. rocket.

blackjack2564
17th September 2010, 07:23 AM
Well another iron in the fire:

Since I'm rebuilding one 3inch Wildman...why not do another!

This one also suffered a cato at Red Glare last fall during a drag race and not much left of the fincan.

But actually a simple basic fix as you will see that anyone can do.

blackjack2564
17th September 2010, 07:41 AM
The problems at hand with this one:

Return it to it's original length.
Re-attach a Kevlar recovery harness,[original all burned up]
Add new piece and keep it perfectly straight and aligned with original.
How to keep it all together safely so it can return to extreme flying.
Not have the new recovery harness interfere with looong motors.

Stay tuned.....

Pantherjon
17th September 2010, 02:47 PM
not bad for a big clunky 3 in. rocket.

If you say so:roll: I disagree however...Now, my UW is BIG and it IS clunky!:bangpan:

Rebuild is looking sharp- as usual! Oh, and that other one? Nothing a little bit of sanding won't take care of!:roll:

Johnly
19th September 2010, 05:42 AM
Paperwork as promised with batch code. Am I reading this right: Aug 5 2009 batch 3 ?

I pulled out my L2300 reload and it has a 090308-02 date code. It's pretty close to your date code, so I guess I'll ask the Mfr before I burn it.

John

blackjack2564
20th September 2010, 01:52 PM
First thing to do is cut off damage and square up the remaining fincan.

Same way as above, chop-saw,then paper wrap and sand till square.

blackjack2564
20th September 2010, 02:00 PM
Now I must connect the new tube with the old and get a new recovery harness in.

How? ......... coupler with in a coupler.

Actually a scrap section of airframe, with a slice out of it, cut to fit inside the coupler since they don't make coupler couplers.

Cut out the slice with a chop [miter saw]

I sized it so I could put a new Kevlar recovery strap between the walls of the 2 couplers.

Stood the real coupler on end, inserted my harness, tacked in place with CA.

Then epoxied the home made coupler inside. [after sanding them of course]

View from each end so you can see clearly how I did it.

blackjack2564
20th September 2010, 02:05 PM
My sub-assembly with harness is ready to insert & connect my 2 tubes.

blackjack2564
20th September 2010, 02:24 PM
Before I glue it in, I must sand out all the burnt char from the fincan, sand outside of coupler and inside of new tube.

New tube cut to bring fincan back to proper length.

Then dry fit the parts.

Turning the new tube till I get the best fit and sand the edge till all fits square & straight. Used a framing square and checked from top of tube down the sides above the 3 fin positions till it was correct.

If you only check one side the other may be off.

After getting it aligned, draw line on joint [keymark] so after you take it a apart to glue, you can align correctly again quickly.

Then glue it together.

blackjack2564
20th September 2010, 02:26 PM
Finally at rest, same size as it was to begin with, along side its brothers! [for the 2 stager]

Not that difficult to do, so now you can save your fincans.

G2Rockets
22nd September 2010, 09:14 PM
Jim,
Awesome as always.

John

blackjack2564
23rd September 2010, 01:11 PM
Finished up the re-build.....finally.

Added the tracker bay and bulkplate late to the nose cone, after I taped off the painted outside first. Did not want any foam stuck to the fresh paint. Yeah I know, should have done it before the paint.

3/16 threaded rod with nuts and washer on one end to hold in foam.
Small drink stirrer size straws for the tracker antenna to fit into.Tape bottom shut so it won't fill with foam.
BP and tracker.

Tape straw to side of nc, drop in threaded rod.

blackjack2564
23rd September 2010, 01:18 PM
I got a little over zealous with the foam by using a total of 80 ml, looking back 60ml would have done it.

It expanded rather slow, so there was enough time to place the BP and eyebolt on to hold the rod in place long enough to keep it where it belongs permanently.

The foam the kept rising and pushed the BP off the top. LOL Looks like a ice cream cone.

After 20 min. or so it's hard enough to shape.

Box cutter blade to cut off the excess....

blackjack2564
23rd September 2010, 01:31 PM
The rod is offset in this size cone [3inch] so there is room for the tracker to fit.

Just used a cheap old Ginsu serrated steak knife to cut the foam. Trace around the outside of tracker & get to cutting.

Test fit, slides right in and antenna goes right down side of cone inside to straw.

Buttoned up with Bp and eyebolt in place.

Twice now, this setup has saved the ole Wildman when it landed in water, NC was floating on top like a bobber sending the signal while the rest was waterlogged on the bottom.

blackjack2564
23rd September 2010, 01:37 PM
Finally the finished photo, it was very bright outside so with my cheapie camera, the paint reflects the sun very bad.

Along side it's painted brothers for the 2-stager.

Notice the total rocket is now only slightly bigger than just the fincan for the original. BUT I can still get a 6xl in it.....barely!

IT's ALIVE!!!! To fly again another day!

G2Rockets
24th September 2010, 01:39 AM
cool mower in the background. What motor do you fly it on?

blackjack2564
24th September 2010, 01:45 AM
cool mower in the background. What motor do you fly it on?



Why a JD-350 of course!

G2Rockets
24th September 2010, 02:58 PM
Why a JD-350 of course!

Oh Yeah that's the Green sparky, Right?