#1
|
||||
|
||||
New Design -- Centuri 1972 "0810" 1.30X
Wandering through the Centuri 1972 catalog, I came across three "non-kitted" designs on page 54. I had worked them up in the original sizes back in September 2005.
Since we all know I *can't* leave well enough alone , and now that the Semroc Nose Cone Designer is up and running, I took a crack at upscaling the middle ST-8 and -10 design slightly. I noticed that ST-8 and -10 upscale by 1.29X to ST-11 and 13. The slightly bigger version turned in some pretty good performances. So while I don't have an official name for it, I call it the "0810" design, referring to the original body tube sizes. I'll post the nose cone and reducer/transition files separately. http://forums.rocketshoppe.com/show...893&postcount=2 http://forums.rocketshoppe.com/show...897&postcount=3 .
__________________
Jay Goemmer "Centuri Guy"/"Tau Zero" YORF Member 28 Semroc SAM #0029 NAR 86131 "I think about organizing things all the time. Never seems to happen. I find something that piques my interest and I'm off on a quest. Or a Centuri. " --Bill Eichelberger, 02/22/2022 “Centuri fret buzz in an updated form.” Bill “Wallyum” Eichelberger re: Estes Flutter-By 03 Sept 2014 Last edited by CenturiGuy : 02-25-2012 at 10:04 PM. |
#2
|
||||
|
||||
You seem to be missing a fin. The thing that I remember about most Centuri designs is the most of them had four fins instead of the three fins that appear in your Rocksim pictures.
__________________
'Til next time, Mike Toelle NAR 31692 L1 SAM 0373 |
#3
|
|||
|
|||
I think the picture in the catalog shows a 3-finned rocket.
Allen |
#4
|
||||
|
||||
So, how many fins ARE there?
Quote:
That's an interesting point. The design on the left shows 3 fins (maybe implying 4 of them), but for some reason I interpreted the other two designs as having 3 fins. This is obviously a case of Your Mileage May Vary. Good catch. Quote:
RockSim gives good results with only 3 fins, but when I upscaled Design #1 to ST-10, 4 fins weren't enough to slow down the deployment speeds. 5 fins might have done it, though. (chuckling) That's why this hobby is so much fun! You can do things your own way, and learn from other people who do it differently. Cheers,
__________________
Jay Goemmer "Centuri Guy"/"Tau Zero" YORF Member 28 Semroc SAM #0029 NAR 86131 "I think about organizing things all the time. Never seems to happen. I find something that piques my interest and I'm off on a quest. Or a Centuri. " --Bill Eichelberger, 02/22/2022 “Centuri fret buzz in an updated form.” Bill “Wallyum” Eichelberger re: Estes Flutter-By 03 Sept 2014 |
#5
|
||||
|
||||
I don't see but two fins!
__________________
Carl McLawhorn NAR#4717 L2 semroc.com |
#6
|
||||
|
||||
Quote:
(...He said, pointing his finger at himself... )
__________________
Jay Goemmer "Centuri Guy"/"Tau Zero" YORF Member 28 Semroc SAM #0029 NAR 86131 "I think about organizing things all the time. Never seems to happen. I find something that piques my interest and I'm off on a quest. Or a Centuri. " --Bill Eichelberger, 02/22/2022 “Centuri fret buzz in an updated form.” Bill “Wallyum” Eichelberger re: Estes Flutter-By 03 Sept 2014 |
#7
|
||||
|
||||
I wonder about the balsa grain on the third model ... is there a benefit to running it that way ?
|
#8
|
||||
|
||||
Quote:
.
__________________
Jay Goemmer "Centuri Guy"/"Tau Zero" YORF Member 28 Semroc SAM #0029 NAR 86131 "I think about organizing things all the time. Never seems to happen. I find something that piques my interest and I'm off on a quest. Or a Centuri. " --Bill Eichelberger, 02/22/2022 “Centuri fret buzz in an updated form.” Bill “Wallyum” Eichelberger re: Estes Flutter-By 03 Sept 2014 |
#9
|
||||
|
||||
FWIW...
Look very carefully at the fins from #3, and you should recognize them. Or at least, you have seen the shape used in other designs, twice... ...And not by "Brand C", either...
__________________
Craig McGraw BARCLONE Rocketry -- http://barclone.rocketshoppe.com BARCLONE Blogsite -- http://barclone.wordpress.com BARCLONE Forum -- BARCLONE Forum BARs helping BARs SAM 0044 AMA 352635 |
#10
|
||||
|
||||
Quote:
As shown in the pic, I agree, that grain orientation does make the outer tabs (tips) more sturdy. But it leaves the inner corners, below the exhaust, susceptible to breaking along the grain lines. To fix that, the grain should run parallel to the leading edge, but then that would result in the outer tips wanting to snap off. (Push it in here, it pops out there...) For that shape, with ordinary fin stock, it's a no-win situation. There's gonna be a weak spot. But some paper lamination would probably help. Or maybe make up some home-made balsa ply. Or cut the fins as two pieces glued together such that the grain lines are optimal in both directions. Doug .
__________________
YORF member #11 |
Thread Tools | Search this Thread |
Display Modes | |
|
|