Activity

If you go to http://www.aerotech-rocketry.com/ and click on “resource library” and then go to “RMS motor assembly drawings” and if you start pounding around there, you will find all the drawings for the various reloads, nozzles, etc.At any rate, the…   Read more»

Thats odd, both the J90 and J135 I flew had only the center hole open. All of the others were closed. Interesting. I was told that only the center hole should be open. John, could it be that the nozzles…   Read more»

I don’t know about that…The 54mm casings can take a LOT more pressure than they normally run at – failure should be around 1600psi from what I’ve heard, while they normally run at 700-900. So, it could easily have had…   Read more»

Or, the ones I had were flawed in the sense that more of the holes should have been open?

Ken, a closure would have blown on your casing if it was flawed in this way.

8)I traded E-mails with Mike D at Cessaroni last week. He was doing the last test on the M795. Then on to recert…The M520 is next and the N1100 after that. All should be ready to go soon. They will…   Read more»

Hmm – looking some more at the drawings, it appears that the M750 only has the central nozzle of the 98mm medusa open – I wonder why it has the medusa then…

Looking at the drawings on the Aerotech site, the J90 should only have the center hole open, the J135 should have the center and 2 side ones (if you oriented this carefully, you could get perfectly even flow), and the…   Read more»

Thats odd, both the J90 and J135 I flew had only the center hole open. All of the others were closed. Interesting. I was told that only the center hole should be open. John, could it be that the nozzles…   Read more»

OK, so in that case it shouldn’t be a problem…I’m looking forward to seeing some of these new loads at LDRS – not just flying, but in the Aerotech tent. I’ll look to see if these appear to have this…   Read more»

OK, so in that case it shouldn’t be a problem…I’m looking forward to seeing some of these new loads at LDRS – not just flying, but in the Aerotech tent. I’ll look to see if these appear to have this…   Read more»

Each have just a central throat.

Yes, but are any of the throats on the nozzle other than the center one open on the J135? If not, it acts just like a single throat…

I’ve flown both the J90 and the J135. Both use medusa nozzles and both have offset cores.

I know the J90 has a medusa with only the central throat open, essentially making it a single throat. I thought the other 54 long burns were the same. I’ll have to look at that and see – now I’m…   Read more»

J135s and K185s both have medusa nozzles. IIRC, the J90 is in the same boat. Ditto for the Ellis L330 and the AT K250 single use motors.I’ve had erratic flights with all the above, except the J90 which I have…   Read more»

The J135 has a medusa?I thought that the long burn 54’s only had the central throat open, essentially making them single throats…

I really dislike medusa nozzles. I have had many flights that corkscrewed with medusa nozzles, but I knew the fins were on absolutely straight because the same rocket flew fine with a traditional nozzle.The medusa sits below a core that…   Read more»

It isn’t a rocksim, but I found the thrust curve…Here are the instructions for the M750One thing to note that I forgot about before is that the M750 needs a new, larger aft closure (it uses a medusa style nozzle…   Read more»

I’ll definitely try to post it here if I see a sim file :)I’d love to see one too 🙂

The M750 isn’t quite as big as the M795 (it’s 9,325Ns), but it comes as several grains that are glued together with epoxy in assembly. Result: none of the shipping problems or DOT issues that you have with the big…   Read more»