Just a wrap up on the G-80 cato.... I received my compensation from Aerotech today. A pair of G77-10R Loadable Motor System kits - one for the G80 and one for the rocket. All in all a fair shake, I think.

I never thought much about this... CATOs are pretty rare. Then I had TWO G80s CATO for a TARC project! AAAAAAGGHHHHH!!!!

Do *not * use lot #010406!

Some of you guys might be interested to know that the G80 that blew up on me on 9/9 was #001436. It went overpressure with enough force to blow out both ends, and there are parallel cracks in the case running about 80% of the length of the case. Neither the delay grain nor the propellant grain show any obvious sign of ever having ignited.

Ken Reilly

😯 😯 😯 😯

I just saw this today. My SSS rocket has one from lot 001436 in it. It's attached in a way that I can't get it out now without really destroying the rocket, so I guess I'll just hope for the best...

If it catos, well, I would have probably lost it anyways...

Those who saw my SSS at Oktoberfest know I'm stuck, too. Can only remove the motor once, after the flight. Since 1965, I've never CATO'd. 'Bout time, I guess. Rocket gods won't let that go on forever. Hey, as long as it doesn't hurt the MAWD, I'll give it a shot. I'm set for 6500' according to the sim if I can add another 4 oz. So, we'll see. 🙂

.... Since 1965, I've never CATO'd. 'Bout time, I guess.

Never CATO'd????? goodness, what a charmed life you live!

I had the mother of all CATOS many years ago on a PML Ariel at the Atlas site. It is not uncommon for parts to be found to this day. Most of the old timers remember the flight well. It was an I284, and it had blowby at about 900'. Parts rained down for a long, long time. Heck, the way they are still being found, apparently they are still falling :-O

I had two G80s CATO out of three flights on my TARC project last year.

I keep a very detailed log. I've had exactly 200 HPR flights... I'll have to look. I believe I've had perhaps 5 CATOs?

JW

Well, my friend, I am due... won't be as spectacular as yours though. 🙂

I have only had one cato, and it was a relatively insignificant one, causing little to no damage...

I think I too am due...

We'll have to see, and if all goes well, I should be good for 7600 or so...

As long as the Alt15k is ok, a cato really wouldn't be too bad though...

7600' would be an awesome blast by any measure. FWIW, I've found the G80 .eng files to be outrageously inaccurate, but you never know. The highest I was ever able to get the older, higher-NS G80's was something like 5100'. That motor had something like 20NS more total impulse than what we are flying today.

My G55 shot is still a TRA record, but my TRA "L" record was recently broken http://www.tripoli.org/records/single.shtml

Note all the new records on that link... the J is now near 20K (!!!), the K is over 28K, and the L was incremented higher as well. I personally witnessed a new N record at BALLS this year, which has not yet been posted on the above link. It was in excess of 46K.

In all honesty, if it doesn't cato, breaks a mile, and I recover it, I'll be happy. 7600 would be awesome, but a nice, decently high, recoverable shot is all I want...

JW, let me clarify. I haven't had a motor CATO yet. At Oktoberfest, I put a "Wilke" charge in my Vertical Assault booster and blew the top of it off. Chris' dad caught it in great detail. I blew my drogue off its shroud lines. You can see it floating away. While my main charge went off, I had already blown the main chute out at apogee at 7456'... which is why I walked way past the east fence at the North site. I'm really getting to know the North site really, really well. 😉 Why are all my failures caught in fantastic detail? 🙄 Ha! Chris, if you can boost to 7600' that would be spectacular. But, JW's right. The .eng files in Rock Sim and/or SpaceCAD, all software packages that use WRASP files, are inaccurate. For example, when I use the 120 N/s G80 I get LESS altitude than the 100 N/s G80. The G80 files are faulty, by a long shot. Our luck, right? Doesn't matter, just shoot it, and we'll all see who CATO's, who wins, etc. This is for fun. 🙂 I'm really impressed that you rolled your own tube out of CF. Very nice.

JW, let me clarify. I haven't had a motor CATO yet. At Oktoberfest, I put a "Wilke" charge in my Vertical Assault booster and blew the top of it off.

Hmmmm.... I seem to have an unearned reputation for charges 🙂 You aren't the first that has made "Wilke" into an adjective when it comes to charges... FWIW, I ground test everything, and I keep very strict records. Many of my charges are less than 0.25 grams. My M hybrid uses 1.25g, which is pretty amazing for a rocket that big. My L3 used 7g, but that is because it takes... 7 grams on that particular rocket.

There is no worse thing than wrecking a rocket by using the "if-some-is-enough-then-too-much-is-just-right" technique. Always ground test.

I do add a smidge to what ground tests show for drogue charges, just in case the rocket is leaning (binding) on itself at apogee. I also take the higher altitude into consideration, as bp doesn't do as well above about 18K MSL. But how often does one venture up that high?

J

Well, the rocket is (almost) done - just need to fill in a few pinholes.

Mine sims lower on the old G80 too, but it still sims to 7200 on that motor, so I think a mile should be obtainable without too much trouble.

Here's a pic of my rocket next to the altimeter: http://www.putfile.com/pic.php?img=3830069
And next to the motor: http://www.putfile.com/pic.php?img=3830033

I can BARELY fit it all in - it's a really tight squeeze. Everything but the nose cone is CF (and hand made). Should be interesting to see how it turns out. 😀

John, when I joined the club, a "Wilke" charge was already a well established adjective amongst many of the folks who call you friend... Perhaps it is due to one or two particular incidents, but... it has taken on something of a life of its own. I probably deserve more of that rep than you do given that I have blown a hole in the side of at least 1 rocket and seriously spiral fractured a piece of filament wound when the piston hung up. You might recall our little same day attempt on the club J record with J570's last year when I used nearly a gram in a 38mm bird...

Perhaps we should call them "Warren" charges...

Warren

If I'm not mistaken, the "wilke charge" moniker came about when JW was ground testing in his neighborhood and set off car alarms down the block. Any overly aggressive charge has since been so named as a term of endearment and not out of spite or malice. I for one, still believe it is better to blow it up than not blow it out. Ground testing is only that - ground testing. It's a whole different animal in the air, under thrust - even if coasting over. That's another reason it's called rocket science.

My Vertical Assault was ground-tested numerous times (I always video my tests so I can analyze it later... and laugh). At the last minute (always a mistake to change things at... the last minute), I added a "little" more to the motor ejection charge than I should have. It's amazing how much BP changes from canister (containment) to canister, from rocket to rocket, with a piston, without a piston, etc. My phenolic tubing (not FG) had grown weak through many flights; otherwise, it would have just shot things out with no problem--with a long harness. JW, you caused car alarms to go off?! Cool! 8) I'm concerned about ground-testing my L-N rocket this winter... so I'm going to do it at Ken Plattner's house. Thanks, Ken! 😈 And, you're absolutely right, Joe. The first time I shot the VA off in DD, the chute hung in the tube. It didn't do that in ground-testing. It blew out fine and hard. However, as you pointed out, in flight everything got crammed down into the tube, and it all didn't pop out as planned. Rocket science, yes... and comin' in on a fin and a prayer! 🙂

Speaking of Wilke charges, we'll have to see how my SSS rocket does. The FULL G80 charge (anyone know what that is? Something like 1g IIRC?) will go off in a 29mm by 1/2 inch space. Should make for some interesting confetti...

I don't care too much about the rocket though, as long as I get the altimeter with data back...