Are you kidding me Eric?! That’s awesome! What are the odds, there can’t be that many of these out there. I think that conclusively answers the question for this particular setup. I suppose anything will work so long as there is spacing for thrust rings. The more I thought about it the more I realized that D is totally right. The tubes will transfer so much load that it doesn’t matter. What I may do is add another centering ring or two, it only comes with three and with a four foot 98 mm surrounded by 8 more motors a couple extra should probably be used. Eric, any chance you could save me some time by sharing a rocksim file with me? Otherwise I would take a 5.5” model and have to scale it up and redo the cluster, not a big deal but any time saved is always good. I’m at
[email protected] if you have one. Don’t suppose anyone else out there has a 3/4 Nike Smoke model with molded fins in rocksim if Eric doesn’t? Although the mmt is really what I’m after. Did you like the rocket Eric? Was it a PR and how were the fins? Thanks bud!
Hi Dan,
Yes, we had the Performance Rocketry 3/4 scale Smoke. The fin can was molded in 4 pieces, joined into one at Perf. Rocketry. No fin tabs. The can needed reinforcement internally and externally as it was a bit....uhhhh....fragile. The later version went to foam filled fins added to a core tube which appeared to be a far superior setup.
Did I like it?
It was a love/hate relationship.
The good: The thing looked sharp in the field and in the air when it worked. It was an attention getter and I'm glad to have built and flown it.
The bad: THAT FINCAN! Was flimsy to begin with so the fins got filled with 2 part urethane foam from US Composites. When filled with foam, they split at the seams, so the seams needed to be glassed on the OD, faired and filled, etc. And there was no support at the fin base; just a 90 degree change in direction for the cloth which tore easily. And it didn't fit the airframe. And so on....spent a lot of time on that can! Again, the later revision with individual fins that arrive foam filled appears much superior at the expense of a bit of room on the internal side (conflicts with motor mounts).
While I'm being negative: another item that you're addressing, and Tim Dixon was set to address also (see his thread) was the limited recovery space. Sticking to scale and using the 20 or 22" couplers, plus that goofy fincan, you didn't have much room for anything recovery related! I set up mine for a couple of options...there was NOT enough room in the lower section for a traditional drogue setup, so it was initially setup for tethered main out the top. It also flew single deploy with the nose and airframe recovering on their own chutes. Further, there was a full length of 6" phenolic built into the nosecone. If I were to fly it again, one or more altimeters would've gone in the nose and the main would've come out of that 6" tube. I *think* you're intent of adding 3' will take care of the tight recovery quarters!!!
One more negative: the rocket was cursed! First flight: launch system malfunction led to a disaster. Second flight: launch system issue led to a great flight, just a bit more exciting than anticipated. Third flight went well; the curse was apparently lifted so we ditched the rocket!
Photos of the last flight at Midwest Power 10: (1) 98-17,500 Sconnie White airstarting (4) 54-2550 Sconnie Sparkies for effect!
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I don't have a Rsim file...not much of a fan. I have Cad drawings and more photos somewhere, but that goes back a few computers, cameras, and years! I'll see what I can dig up!
Cheers!