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The washer goes into the powder well of the bulkhead after you drill the delay. The powder is then poured into the well and over the washer. The washer ensures a powerful ejection charge so that none if the ejection escapes out of the aft end through the nozzle.

I am glad that AT did something about this. I was told to " relax and have a beer" when I brought this up awhile ago. Search "DMS safety concern" thread from last year. The DMS motors I have don't get used unless I have electronics b/c of the huge ejection well hole.
 
I went to a launch today, and saw my first L2500 Super Thunder for the 98/5120 case. Holy crap, that motor is a beast!
 
I am 99.99998% sure that I'm overthinking this, but this is my first foray into 38mm rocketry (and my first time with AT motors) and I don't want to blow it...
OK, so OpenRocket has a "delay" time.
My conception of this is from the old Estes rocket diagrams - you have the "thrust" burn, the delay burn, then ejection charge. So a C6-5 burns for 1.6 seconds, coasts for 5 seconds, then (6.6 seconds after ignition), ejection happens.
Was reading the Aerotech instructions and it says "Insert the black-coated end of the igniter into the nozzle opening and push itcompletely into the motor core, until the coated end is touching the time delay element in the motor bulkhead." ... So am I igniting both the propellant and the delay charge? If that's the case and the delay starts burning at ignition, if I've drilled my delay down to (for example) six seconds, and there's a burn time of 2 seconds, would that be a 4 second delay according to OpenRocket or a 6 second delay?
This feels like a stupid question and I apologize for that, but I just want to make sure....

Thanks!
 
Are you planning to demo any new motors at the upcoming NSL? I would love to see the new hazmat free J reload fly!
 
I am 99.99998% sure that I'm overthinking this, but this is my first foray into 38mm rocketry (and my first time with AT motors) and I don't want to blow it...
OK, so OpenRocket has a "delay" time.
My conception of this is from the old Estes rocket diagrams - you have the "thrust" burn, the delay burn, then ejection charge. So a C6-5 burns for 1.6 seconds, coasts for 5 seconds, then (6.6 seconds after ignition), ejection happens.
Was reading the Aerotech instructions and it says "Insert the black-coated end of the igniter into the nozzle opening and push itcompletely into the motor core, until the coated end is touching the time delay element in the motor bulkhead." ... So am I igniting both the propellant and the delay charge? If that's the case and the delay starts burning at ignition, if I've drilled my delay down to (for example) six seconds, and there's a burn time of 2 seconds, would that be a 4 second delay according to OpenRocket or a 6 second delay?
This feels like a stupid question and I apologize for that, but I just want to make sure....

Thanks!

The delays work just like the Estes ones other than they are adjustable, For Example an F39-9T is just that 1.3 seconds burn (39newtons max thrust) with a delay of 9 seconds(after the motor burns), if you need a 6 second delay you drill a 3/32" deep hole in the delay which reduces it to a 6 second delay (pretty close, 1/32" approx=1 second). Composite delays are lit at the same time as the motor but the delay is still read the same way even though the delay grain may burn longer than 9 seconds FROM IGNITION OF THE MOTOR, that's why delay grains are not simply one single formula of delay composition (and are mostly not interchangeable). Using the proper delay drilling tool helps make it easier.
 
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The delays work just like the Estes ones other than they are adjustable, For Example an F39-9T is just that 39newtons max thrust witha delay of 9 seconds(after the motor burns), if you need a 6 second delay you drill a 3/32" deep hole in the delay which reduces it to a 6 second delay (pretty close, 1/32" approx=1 second). Composite delays are lit at the same time as the motor but the delay is still read the same way even though the delay grain may burn longer than 6 or 9 seconds FROM IGNITION OF THE MOTOR, thats why delay grains are not simply one single formula of delay composition (and are mostly not interchangeable). Using the proper delay drilling tool helps make it easier.

One minor correction the F39 has an average thrust of 39 newtons- not a max thrust of 39 newtons.
 
I flew my first 98mm motor this weekend-- AT's N1000 in the 98/15360 hardware. The motor casing and all components were brand new, so I was really surprised when I was cleaning up afterward to see that the forward seal disc had a chunk missing from the inside edge. Thankfully there was no failure and I had a perfect flight and recovery, but obviously this seal disc cannot be used again. I have never had a forward seal disc get damaged in flight before on any smaller motors including 75mm. Question for Charlie or those with experience-- have you seen this before? Is this normal wear and tear with these giant motors or did I get a bad copy?

98mm FSD 1.jpg

98mm FSD 2.jpg
 
You might need a stainless steel disk for those long burn motors.

I'm sure it couldn't hurt, but I did check the instructions carefully and it did not indicate SS required. As far as I know that new SS FSD was made for the 98mm Super Thunder reloads.
 
I flew my first 98mm motor this weekend-- AT's N1000 in the 98/15360 hardware. The motor casing and all components were brand new, so I was really surprised when I was cleaning up afterward to see that the forward seal disc had a chunk missing from the inside edge. Thankfully there was no failure and I had a perfect flight and recovery, but obviously this seal disc cannot be used again. I have never had a forward seal disc get damaged in flight before on any smaller motors including 75mm. Question for Charlie or those with experience-- have you seen this before? Is this normal wear and tear with these giant motors or did I get a bad copy?

I used a M1939w for my L3 flight. A 2005 motor that was originally set up with the phenolic forward seal disc. SO, I used a brand new AT aluminum seal disc with o-ring. When I was cleaning the motor parts, I found the seal disc had a notch burned out of it. Mine wasn't burned as big as yours, but I still didn't wanna use it again. Dr Reese looked at it and said it would be fine, so I gave it to him... The new AT stainless disc is on my short list to buy, especially since I got another older M1939 to fly...
 
Not to disrupt the chain of thought with the larger motors but any chance the Super Thunders are coming to the 29mm line anytime soon?
 
I believe the G138 is straight-up Blue Thunder. I suspect the post is more about the 29mm HP line (29/180, 29/240, 29/360, etc)...

Oh ok. Well either way that G is one heckofa kick in the pants for a G motor.

Super Thunders in any size are welcome. That H550 is wicked.
 
I flew my first 98mm motor this weekend-- AT's N1000 in the 98/15360 hardware. The motor casing and all components were brand new, so I was really surprised when I was cleaning up afterward to see that the forward seal disc had a chunk missing from the inside edge. Thankfully there was no failure and I had a perfect flight and recovery, but obviously this seal disc cannot be used again. I have never had a forward seal disc get damaged in flight before on any smaller motors including 75mm. Question for Charlie or those with experience-- have you seen this before? Is this normal wear and tear with these giant motors or did I get a bad copy?

Same thing happened to a new fwd seal disc used in my K1103X at LDRS this year. I had never seen an aluminum seal disc "chewed up * like that until then.
 
Well, I don't want this to sound like I'm mercilessly flogging the deceased equine, but what's the word on the 24-60 reloads, and the Redline for the 29/40-120? Anything?

Phil L.
 
Another +1!
The big stuff is fun to see, and enjoy, however at our launches, mid power flights are at least 5x the number of high power flights, and even high power flights, H and I are at least 3x more.
Several people who use to fly 75mm and 98mm and even 54mm, now fly 24mm, 29mm and 38mm MD including my self.
I personally encourage the smaller sizes due to costs, the challenge to fit every thing in those sizes and to fly our field!
 
And more +1
It would be 6 to 12 months after they are readily available in the US before they make it across the pond, so the sooner they hit the market the better ;)
 
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