Steve, thank you for gathering additional input here from AT, much appreciated!
Justin
You're welcome, of course.
Steve Shannon
Steve, thank you for gathering additional input here from AT, much appreciated!
Justin
I received clarification from Charlie. If the rocket is one that will be subjected to high acceleration, glue bonding the grains makes sense. For rockets with a lower acceleration gluing the grains is not necessary. I'll talk to the rest of the board to see what, if anything, needs to be added to Paul's announcement.
Steve Shannon
My question would be what counts as "high acceleration"? >20G? >60G? The famous (in my area at least) Nike Smoke K2045 drag race seems to be around 50G's, with the K2045 hard-to-get it was recommended to use the K2050ST instead, and the loads showed the day the race was supposed to happen (though the race was changed last-minute due to the fact that these motors turned out to be plugged when it was advertised they'd be -14A's). And are there instructions on how to do the bonding? I haven't flown anything that required bonding before, though I have a K2050ST waiting to go in my Nike Smoke.
Aerotech has a nice grain bonding PDF at the very top of their instructions page. I bonded my first bonding-necessary motor, an M650, last September and it was terrifying, but it didn't need to be; I was just nervous. It was easier than I thought and flew great.
Personally, I would consider the entire range you listed as high acceleration, but there are much more aggressive flyers than me.
Steve Shannon
Aerotech has a nice grain bonding PDF at the very top of their instructions page. I bonded my first bonding-necessary motor, an M650, last September and it was terrifying, but it didn't need to be; I was just nervous. It was easier than I thought and flew great.
Personally, I would consider the entire range you listed as high acceleration, but there are much more aggressive flyers than me.
And those instructions expect there to be spacer o-rings, which I think someone else already noted aren't supplied with this motor. So where is one supposed to get those? Really seems like AT didn't think this one through.
Yeah, it's an extremely subjective term, so it seems like a bad phrase to throw around, it has no meaning. I guess the other question would be what flight with a K2050ST isn't high-acceleration? Seems like any motor that only burns for ~0.7s is probably going to be "high-acceleration", or else fail to get the rocket safely off the pad.
And those instructions expect there to be spacer o-rings, which I think someone else already noted aren't supplied with this motor. So where is one supposed to get those? Really seems like AT didn't think this one through.
Other posts have pointed out the the size of the o-rings is not crucial. They're just there as grain spacers while gluing the grains into the liner to prevent the grains from moving under high acceleration, so a trip to the nearest hardware store and a Mark 1 eyeball should be considered.
Steve Shannon
I think that shows excellent sense! I would buy the smallest thickness O-rings that fit into the liner without bunching up. RCS Rocket Motor Parts Company (Aerotech's parent company I believe) sells O-rings separately. I tried to see what size of O-rings were packaged with the 75 and 98 mm reloads which require O-rings, but failed.However, this begs the question: Is there enough room to add the spacer o-rings? If too much space is taken up in the liner, one runs the risk of not being able to get the forward seal disc in. I assume a dry fit or two might be in order...
Charlie,
I'd like to put in a plug for more reloads for the 1 grain 75mm case.
Steve,
We will be developing some new 75mm loads this year, the goal is to have some to demo at BALLS. Will let you know, keep pinging me for updates.
+1 to this as well...
Preston
As long as we are putting in requests, I would love a non-hazmat reload for the 38 480 case (which is suspect is the practical size limit for the smaller grain size required).
I'm looking forward to flying these K-2050's this year...
View attachment 308999 View attachment 309000
Roger that Preston. Will we see you at LDRS this year?
The dry-fit is step 2 in the bonding instructions. It may not clearly state to dry-fit with the spacers, so if you don't realize until later on that spacers are even required you might miss that in the dry-fit step and realize you're screwed only after the glue is in place. But it certainly seems like the size of the spacers should be very important, not a "don't-care". Would be much better if AT just provided the necessary parts, they do with every other motor, don't they? Or do customers usually have to source their own spacers?
Good morning Charlie,
I recently took delivery of (2) K-2050's. Based on posts in this thread, the grains need to be bonded to the liner. Question is, does the K-2050 get bonded to the liner WITHOUT grain spacer o-rings? Both of the K-2050's did not include said O-rings, so I wanted to make sure long before I glue one of these rascals together. If they DO require grain spacer o-rings, what is the dash number please?
Thank you sir,
View attachment 309152
You're welcome, of course.
Steve Shannon
Yeah, it's an extremely subjective term, so it seems like a bad phrase to throw around, it has no meaning. I guess the other question would be what flight with a K2050ST isn't high-acceleration? Seems like any motor that only burns for ~0.7s is probably going to be "high-acceleration", or else fail to get the rocket safely off the pad.
And those instructions expect there to be spacer o-rings, which I think someone else already noted aren't supplied with this motor. So where is one supposed to get those? Really seems like AT didn't think this one through.
Of course!
Preston
...That being said, bonding will not hurt and you will get the max performance from the motor this way.
I think that shows excellent sense! I would buy the smallest thickness O-rings that fit into the liner without bunching up. RCS Rocket Motor Parts Company (Aerotech's parent company I believe) sells O-rings separately. I tried to see what size of O-rings were packaged with the 75 and 98 mm reloads which require O-rings, but failed.
And I want to point out that at no time did Charlie say that glue bonding the grains was required, so feel free to fly without gluing the grains.
Sounds good... I plan to bond mine without o-rings...
Thank you!
I'd like to give a shout out for AT customer service. I acquired a M2400BT motor but the nozzle seemed to be off, the throat was very small for a 3 grain M motor. Sent an email and got immediate response from Karl. He pointed me in the right direction on what nozzle I needed to purchase and in the end he even bored it out to the correct throat size for me.
Awesome customer service, Thanks AT!
They made you buy a new nozzle ?
This was from a motor that I obtained from someone going out of the hobby. It was out of the package, mixed with parts and pieces from many different motors. Me not having the correct nozzle was not the fault or error of Aerotech. Karl with AT asked a few question to enure the grain geometry was correct for the M2400T and then told me which nozzle I needed and what the throat should be. I sent him a couple pictures of the grains and from the dates hand written on the them he figured these could have been some of the first Blue Thunder 98mm grains cast.
Thanks again AT, keep up the good work!
I flew an old AT 24mm G46W today. All I can say is, PLEASE MAKE THESE AVAILABLE AGAIN. Please, pretty please. If not this exact one then some other 24 mm single use Gs.
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