Semroc PSC infinity

[Joekeyo]

Is anyone familiar with the OOP Semroc PSC infinity. I recently bought one, and have yet to fly it. Have you flown it on smaller engines i.e. A8-3? Is there an Open Rocket file available? The Kevlar cord seems short, is it going to zipper on the 1st flight. Any comments on it's performance?

 

[kuririn]

Rocksim file is here, OR can read it:
https://www.rocketreviews.com/rocksim-semroc-psc-infinity.html
I have built one but have not flown it yet, so I cannot tell you anything about the performance.
The instructions I had did not show the step of attaching the streamer to the short Kevlar leader in the booster section.
BTW there should also be a longer Kevlar leader for the sustainer.
Forum member John Brohm can give you more info, he helped design this model.

 

[John Brohm]

The PSC Infinity was the result of a design competition intended to produce a commemorative kit/model celebrating PSC's 25th anniversary as a club and NAR section. How the kit came to be can be found in issue #158 of Team Pittsburgh, PSC's newsletter, found here: https://www.psc473.org/Newsletters/Issue158.pdf

The PSC Infinity would never have got off the drafting table if it wasn't for the kind support of Carl, Sheryl and Bruce at Semroc. PSC is indebted to those gracious folks, and we commemorate Carl and Semroc each Fall with our two-day Carl McLawhorn Memorial Flyoff. CMMF VII is scheduled for this coming October 19-20, and the events are listed on our website, PSC473.org

As to the question of motor choices, I've flown my model quite successfully on both B and C boosters staging to long duration B and C sustainers. There's no reason not to try A8s in the upper stage, but I'd be shooting for the A8-5 if you build your model light. I can't recall the stock shock cord, as I usually use a Kevlar anchor connecting to an elastic braid about 2x the length of the model. Never have had a problem with this arrangement.

Best of luck with your PSC Infinity - it's a great model to build, and a fun model to fly!

John

 

[MALBAR 70]

I have one built and have flown it several times staging B/C 6-0 to A 8-3/5 and have had no issues. The only problem was, on the first flight, the streamer for the booster got severely roasted. I have yet to replace the streamer materiel. This is a very fun rocket to fly. What's not fun about clustered two stage rockets?

 

[Joekeyo]

Thank you everyone for your generous responses.

The instructions for the booster streamer were vague. My strategy is to tape a short piece of shroud line to the free end of the streamer. Roll up the streamer leaving the piece of shroud line hanging; wrap the streamer with recovery wadding and place the rolled up streamer/wadding into the booster. Assemble the booster/sustainer with the shroud line hanging out of the rocket.

I have made a small hole in one of the sustainer fins close to the BT. Run the shroud line trough the hole and secure the line to the fin with a paper shroud line fastener. My plan is that the streamer will be pulled out of the booster at separation by this static line. The line should be sufficiently loosely coupled to remove the streamer from the booster, yet rip away from the sustainer after the streamer is deployed. Like so many other things, this is harder to explain than to do. I'll let you know how it all comes out (sort of a pun).

 

[Joekeyo]

I just finished reading some of the articles in the newsletter. Those about the Infinity and the one by Vernon Estes. Very interesting and informative. I am looking forward to reading the rest of the newsletter. Thanks again.

The rocksim file is nice. Motors won't load into the file. Is it because it's a rocsim file?

 

[kuririn]

The rocksim file is nice. Motors won't load into the file. Is it because it's a rocsim file?

No, OR should read it. I tried loading motors into the file and was able to after some difficulty and multiple attempts. Don't know what the problem is. Anyway here's a .pdf of a sim using 2xA8-5s and 2X B6-0s:

 

[Joekeyo]

Ok Ok. I got it to add motors and run simulation. Used New configuration button, duh! Next question: How do the simulation compare to field derived data?