# F21-6 Cato

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#### rbeckey

##### Well-Known Member
On 07/29/04 I used two AT F21-6 motors for my Estes 1952 V2. I used the supplied ignitors, which worked perfectly. The first flight was faultless, and my new rail pad was the perfect platform. The rocket returned safely only about fifty yards from the pad after an amazing flight. The second F21 burst about half way up the rail ejecting the chute and blowing parts of the motor downward. Inspection revealed the case was cracked in pieces and the motor mount is shredded.
I will take pictures of what I could find later. I understand AT may replace the F21, but what about my shredded rocket? Those things cost $50 when you can find them, and I don't see how I could replace the MMT without destroying the rest of it. Its not like this was a 29/40-120 that might have been improperly assembled in the field. #### loopy ##### Well-Known Member I've no personal experience, but I think they usually do something to help alleviate the pain of the destroyed rocket. Don't forget to file a mess report on this. Loopy #### rbeckey ##### Well-Known Member Pic of failed motor. #### rbeckey ##### Well-Known Member Necropsy of V2 yeilded more motor pieces in the baffle. Rocket is gutted. Perhaps new MMT and baffle can be built, but it won't be easy. #### havoc821 ##### Well-Known Member Man, I'm sorry for your loss. I recently had to deal with aerotech with a F20 cato. The motors ejection charge went off 1 sec into flight. There was still 2 sec of propellant to burn and now the motor burned from both ends charring the inside of the airframe, destroying the baffle and burning through the shock cord whioch meant the booster fell on its own and damaged a fin. Well, I'm sorry. Aerotech seems to be having problems lately with CATOs. #### rbeckey ##### Well-Known Member The AT warranty department resonded quickly to my email and I sent them pics and other data as requested. I'll let you all know how it works out. MESS report filed also. #### n3tjm ##### Papa Elf Originally posted by havoc821 Man, I'm sorry for your loss. I recently had to deal with aerotech with a F20 cato. The motors ejection charge went off 1 sec into flight. There was still 2 sec of propellant to burn and now the motor burned from both ends charring the inside of the airframe, destroying the baffle and burning through the shock cord whioch meant the booster fell on its own and damaged a fin. Well, I'm sorry. Aerotech seems to be having problems lately with CATOs. Was that with their new molded case? #### havoc821 ##### Well-Known Member I don't know what you mean by molded but it has the black case with yellow at the top with what looks like epoxy or something there and a red cap which I guess is to cover the BP for the ejection charge instead of the paper like on other motors. #### n3tjm ##### Papa Elf That is there new molded case. The delay element is assembled like it is in the new RMS plus High Power reloads. I have a G80-4T that uses the new closure. I have noticed that it is not the same modeled closure that the F20's now use. They screw into the casing. Check the nozzle of the motor. Is it molded into the case, or has the nozzle been epoxied in? #### havoc821 ##### Well-Known Member The nozzle is part of the case and the ejection charge/delay is epoxied in. #### rbeckey ##### Well-Known Member AT customer service rep contacted me promptly (8/2) about the CATO, promising to send two F21-6 motors to replace the CATO, but the motors aren't in yet. No mention was made of the rocket damage. IF I can fix the V2, the extra motor will make up for the damage, if not I am about$30 in the hole.

I contacted Estes customer service on 8/3. By 8/10 I had received the centering rings for the V2, and I will use Loc MMT to attempt to rebuild. Estes also replaced a Big Daddy that I lost to shock cord burn through, and sent along 6 each of the larger and smaller size "new" shock cords. That is what I call stellar service!

#### flyr98

##### Well-Known Member
You know, you could also go to the NAR site and report a failed motor.

#### jraice

##### Well-Known Member
Aerotech is very good about sending new motor's or casing's but they wont pay for much of the rocket. I had 3 G35's from the "bad batch" and they sent 3 packs of two F20's because they had no G35's. I also had a buddy at a launch CATO a 38/600 case, I witnessed the building of the motor and everything was correct, rocket was totaled, he got a new motor and case but still... I think they could atleast include a new case and two motor's instead of one.

#### RoyGreen

##### Well-Known Member
Originally posted by flyr98
You know, you could also go to the NAR site and report a failed motor.
no, it goes like this: "You know, you should also go to the NAR site and report this failed motor."

#### the freshman

##### Well-Known Member

I flew my Tall Boy on an F21-6 last month. It didn't have any problems, and made a textbook flight. (My first white lightning motor!) However, after inspecting the casing, I noticed a roundish lump that wasn't there before the flight. It's about a centimeter in diameter, and raised about a 64th of an inch. See attached.

Any connection?

#### RoyGreen

##### Well-Known Member
Originally posted by the freshman

I flew my Tall Boy on an F21-6 last month. It didn't have any problems, and made a textbook flight. (My first white lightning motor!) However, after inspecting the casing, I noticed a roundish lump that wasn't there before the flight. It's about a centimeter in diameter, and raised about a 64th of an inch. See attached.

Any connection?
That motor appears to be a phenolic casing, and that lump is a sign of some delamination going on. That type of problem should not happen with the molded plastic casings. The two catoes are almost certainly unrelated, unless someone at AT is forgetting an aft O-ring.

#### the freshman

##### Well-Known Member
Originally posted by RoyGreen
That motor appears to be a phenolic casing, and that lump is a sign of some delamination going on. That type of problem should not happen with the molded plastic casings. The two catoes are almost certainly unrelated, unless someone at AT is forgetting an aft O-ring.
Luckily mine didn't CATO, I only noticed the lump after examining it after I got back from the launch.

I did a search, but didn't find anything about delamination of casings. Could you elaborate a bit? I'm completely new to AP motors.

#### scm86

##### Well-Known Member
The phenolic cases are made in layers, like a regular body tube, when these layers or laminations come apart its a delamination.

Could be caused by a burn thru of the liner at that point or simply a defect in the case causing the layers to seperate.

Scott McNeely

#### sandman

##### Well-Known Member
I had a CATO with an F21-8 (24mm) Econojet about 2 months ago. The motor blew out its fuel slug after spitting the nozzle quite violently!

The rocket was basically undamaged and was subsequently sacrificed to the rocket gods moments later on the second motor in the packege (it worked just fine BTW).

I sent the remains to Aerotec and they promply sent me a pair of replacements (Cool!).

Unfortunately...both motor had fairly large cracks in the case near the nozzle end!

I was told to send these back to Aerotech (RCS Inc.)

So far I've heard nothing back...This was before NARAM and I'm still waiting.

#### jraice

##### Well-Known Member
The only motor failure I ever had was a G35 that blew some of the nozzle (only damage was a broken retention clip) but that was from a bad batch (I used it anyways). It seems like more CATOS happen with SU motors but they do happen after with RMS as well, just seems like a lot of SU's CATO.

#### Donaldsrockets

##### Well-Known Member
I think CATOs tend to happen more often with Econojet aka Ecatojet SU motors than AT's standard SU motors.

Every SU motor that I used always had those blisters on the external surface of the casing, probably caused by the heat as the original SU motors had no liners.

In fact, an Ellis Mountain G35 that I used had a big lump that broke through the casing when I pushed on it with my fingernail.

Glad that didn't happen during the burn!!!

#### flyr98

##### Well-Known Member
Yea, I know what you mean. Back in July I flew an Aerotech SU G40-4 (made before the fire/re-design) and after the burn there was a very large bubble that breaks through as you said and also many smaller ones.

#### Bart

##### Member
The F-21 has problems. The phenolic case has been substandard and I found out that a new molded case is being planned in the future. Most phenolic case will blister due to the high preasure about 800psi at ignition and intense heat. Also some of the cases were badly spalded on the inside and should have never been made, but I think the almighty dollar made the descision. Your out of luck for getting your rocket fixed. If it isn't made by Aerotech your out of pocket!!!

#### denverdoc

##### Well-Known Member
Used to be that any demonstrable cato not do to user error bought you a rocket. This was in the SU days before reloads. Reloads create another variable--user error. So I can see some DISCRETION here, but to not recoup for a SU cato is unconsciounable. I just bought my last AT anything! Next thing they'll sell is Flight Insurance. And by all means report all failures to the NAR/TRA bodies. Nuff failures, decert....
Good grief,
JS

#### Lucas

##### Well-Known Member
A flew a couple of G35s and the charge did not go off either time resuting in the loss of 2 of my rockets after they came in balistic. A lot erlier I had an AT G80 in a minimum diameter 29mm rocket and it CATOd. The casing shattered and the rocket blew to pieces. It was really weird.

#### denverdoc

##### Well-Known Member
Interesting, I lost 2 rockets to EM EC issues as in not enuf. And things were pretty loose, so from experience know a gram-gram and a half would have been plenty. That said Bob Ellis is making among the more interesting motors available. I had made no official complaint as I just wasn't sure but both were G/H SU motors. Now I need to take my own advice and register the event.
John S