CATO'd G80

[DynaSoar]

As soon as th Mirage took off I knew something was wrong. It sounded more like an Estes E9. Then it quit halfway through the burn, definitely less than a second. The guy next to me said "That's not right." Then it arced over and nosed in, completely destroying it. If the ejection charge went off at anywhere near the right time, it was already crumpled on the ground.

Anyone ever had one of these do this?

 

[rstaff3]

Never even heard of it much less had it happen. The only SU CATO I have had or seen results in the bottom of the motor blowing off and the motor extinguishing. The owner should contact AT.

 

[GL-P]

I saw an E or F SU blow the nozzle. The casing was chipped. We figured the hold on the nozzle was damaged. Then the nozzled was fired like a cannon and damaged the casing real good.

 

[astrowolf67]

We saw a G80 CATO at our last BluesRocks launch. It blew the bottom of a glassed and foamed Callisto fin can apart. I've had one with an early ejection (about 5.5 seconds instead of 7). But never seen one do like yours did.

 

[Karl]

Yep, contact AT , it may be another batch of bad G80's.
Karl

 

[Flyingiazzi]

Rocket and motor should be under warranty if you bought them in the last year.

 

[brianc]

Don't forget to fill out a <a href="https://nar.org/NARmessform.html">MESS Report</a>.

 

[n3tjm]

Did the ejection charge go off? Was there any sign that the case burned through the side? Any remaining propellant in the case. I would give Aerotech a call about it. That sounds like a defective motor; and their warrenty should cover that and the rocket.

Do you have a video of the flight?

 

[r1dermon]

half power and no ejection charge? sounds like the igniter was only halfway in. but, i could be wrong...i'd send it to AT.

 

[Stymye]

yes, It could be the igniter was not fully in, or the grain was oxidised possibly to get the low pressure burn.
did the motor chuff at all?

 

[Chuck Rudy]

Had a G80 blow the cr ap out of my RV Pegasus on it's first flight. Sent the SU case to AT an got this jive piece of paper, the fire happened the next week. I burned the paper in a campfire.....ATs replacement policy sucked back then. Hopefully it's improved.

 

[n3tjm]

Originally posted by Chuck Rudy
Had a G80 blow the cr ap out of my RV Pegasus on it's first flight. Sent the SU case to AT an got this jive piece of paper...

What was the piece of paper? A merchandise voucher? I personally never had a problem with their warrenty procedure.

 

[rstaff3]

I have had 2 AT CATOs, a G35 and a G125. The prior was replaced through the hobby shop where I bought it and the G125 from AT. They felt bad about the delay because of the sparse G125 production schedule, so they sent me two to make up for the delay. This was in 2000. Pretty good customer support in my book. And they always replied to my frequent emails

 

[DynaSoar]

Originally posted by stymye
yes, It could be the igniter was not fully in, or the grain was oxidised possibly to get the low pressure burn.
did the motor chuff at all?

No chuff at all. The startup was just fine, but the thrust was low, or at least the sound of it was. It just sounded weak, and it definitely was too short. The boost looked good at first. I couldn't tell if it was slower than it should have been or not because I'd never flown the Mirage before.

Low pressure sounds about right. The engine was still sealed in its bag until the night before.

Everything appears to have burned -- there's no powder left in it and the cap is burned off. I don't know if the ejection charge went off or just smoldered away. By ejection time the rocket was buried in the corn field.

I bought two at the same time and still have the second. I figure even if they won't replace it I'll offer to send the second if they want to test it, because I don't want to.

 

[shreadvector]

if the propellant had a 'crust' on it, and it ignited at the bottom, you could get the result you described.

What kind of igniter was used?

I find that a Magnelite dipped igniter (even a Copperhead dipped in the magnelite pyrogen) ignites even the most stubborn motor. And, of course, it's important that the pyrogen end be inserted ALL the way to the top of the motor and that it is held in place there until ignition is complete. If it can slip or fall down toward the bottom, it is not good. It is a disaster if the propellant has a crust on it.

Originally posted by DynaSoar
No chuff at all. The startup was just fine, but the thrust was low, or at least the sound of it was. It just sounded weak, and it definitely was too short. The boost looked good at first. I couldn't tell if it was slower than it should have been or not because I'd never flown the Mirage before.

Low pressure sounds about right. The engine was still sealed in its bag until the night before.

Everything appears to have burned -- there's no powder left in it and the cap is burned off. I don't know if the ejection charge went off or just smoldered away. By ejection time the rocket was buried in the corn field.

I bought two at the same time and still have the second. I figure even if they won't replace it I'll offer to send the second if they want to test it, because I don't want to.

 

[DynaSoar]

Originally posted by shreadvector
if the propellant had a 'crust' on it, and it ignited at the bottom, you could get the result you described.

What kind of igniter was used?

I find that a Magnelite dipped igniter (even a Copperhead dipped in the magnelite pyrogen) ignites even the most stubborn motor. And, of course, it's important that the pyrogen end be inserted ALL the way to the top of the motor and that it is held in place there until ignition is complete. If it can slip or fall down toward the bottom, it is not good. It is a disaster if the propellant has a crust on it.

I used a copperhead. It definitely went all the way up -- I tried twice just to make sure. And I've been using both the rubber band and a piece of tape where the igniter crosses the nozzle to keep it from pulling down if the clips hang heavy. Now, if the motor started and blew the igniter down, I'd think it'd still burn from the top.

 

[Chuck Rudy]

Originally posted by n3tjm
What was the piece of paper? A merchandise voucher? I personally never had a problem with their warrenty procedure.

Yep....only good for three months at AT website.....but they weren't selling much after the fire. So I didn't even bother.....guess it was my way of helping them get back on their feet. The rocket was repaired with a bit of fiberglassing, life goes on.

 

[DynaSoar]

While the G80 might have had a problem, it's not the reason for the high speed post hole digger. After talking with Ed at Giant Leap, we agree that the reason for the crash is that Slimline retainers are not supposed to be used with S/U motors. They have no rear thrust ring and so can slip out. They often don't but they might. Mine did.

This wasn't at all clear from the description on the web page or in the instructions. These assumed the reader to have experience with RMS motors in order to clearly understand them. That wasn't a bad assumption to make.

Ed's going to change the instructions to make this clear.

I still think the G80 had a problem, and I believe mine was only one of two that day that did. But it hardly matters now.

Anyway, just wait until the parts from PML get here. The salvaged part of th Mirage rebuilt with the parts on the way will become a far cooler rocket.