What caused the cato?

Yes. This is not uncommon in the event of a sudden mechanical failure of the casing... the hot gases inside the motor are suddenly released, instead of being confined in close proximity to the propellant (and as they drop in pressure, their temperature goes down as well). The net result of all this is that the propellant will stop burning if the case ruptures.

-dave w

roger: from the Aerotech website:

G35W Econojet Consumer Notification AeroTech has identified a higher-than-normal failure rate on certain batches of G35W Econojet motors. The lot codes affected are:

Customers with motors displaying these lot codes are requested not to use them, and to contact AeroTech for disposition and replacement instructions. AeroTech apologizes for any inconvenience this has caused its customers, and will honor all G35W failure claims in accordance with our Warranty Policy

A consumer called AeroTech and recived the following info:

Aerotech will exchange the faulty G35s for either new G35 Econojets or F20 Econojets. The problem is that the G35 is being redesigned and is not currently available, but should be in several weeks. (When pressed, Diane said they were hoping for about 8 weeks or less, but admitted that she was not certain). However, I could have the F20s now.

Rather than have me mail the motors (nearly impossible due to Hazmat issues), Aerotech asked me to remove the paper cap at the delay end of the motor (which is stamped with the lot number and delay) and mail them to Aerotech as proof of purchase. Sounds pretty simple and I thought it was a good way of handling the recall.

hope this helps

shockie B)

Yes. APCP propellents generally self-extinguish when the pressure drops suddenly. The amount of propellent needed to cause a cato is often so small that you may think it didn't burn at all.

This has been discussed so many times, this time you really should google groups for it.

Yes.

You were the most qualified.

They are in there.

You gave a guy $15 of free fun BTW.

Jerry

Since errortech (brand) already suggested CORING PROPELLANT to solve the J350 cato problem, I will go out on a limb and suggest drilling the nozzle by 1/64 of ONE inch to lower the igniton pressure.

They seem to be testing a molded case if you ask me.

Jerry

Contact Aerotech. I had this problem with a two pack of motors (referred to before) and Aerotech made it right. Sent me a two pack of F-21's and a new Initiator for the one it blew. Of course I sent a bunch of documentation. Again contact web site. I was quite pleased with the response.

Their warranty response has improved greatly over the years.

Give credit where credit is due.

Yes, I emailed them and they said the same thing to me. They also asked me to send the damaged part of the rocket, but I think I'd rather try to repair my rocket than replace it.

-- Roger

Thanks for the info.

-- Roger

Interesting characteristic of an "explosive", don't you think? :-)