Discussion in 'The Watering Hole' started by Theo J. Swank, Jun 24, 2019.
This is meant for conversation about nose cones
I like nose cones.
I prefer nose domes although some may say 'I don't see the point....'
I prefer head cones. Hubba Hubba.
Does State Farm offer rocketry insurance?
Saw them do it live in the studio. The NBC pages (ushers) were convulsing in the aisles.
The re-purposed Cookie Puss -
COOKIE O' PUSS for St. Patrick's Day!
I like them when you can retrieve them "WITHOUT" a shovel and a pick and several hours of sweating your nutz off.
Now that we've had our fun, do you have specific questions or ideas regarding nose cones or related techniques?
Wait a minute. I haven't had my fun yet....
I could go for an Ice Cream Cone right about now... Tillamook Mint Chocolate Chip Ice Cream, waffle cone... 3 scoops....
ohhhhhh I've only had one Mint Chip Ice Cream Cone in China (and unfortunately for me the location closed down since then)
Actually my preference is for nose pyramids. Easy and cheap to make. Given they are paper and easily crushed they are likely safer in the rare event of a ballistic reentry.
I have been experimenting lately with different 3 d printed parabola style cones and was wondering if anyone else has done this
do you have a preferred length
I regularly see printed variants of parabolic, elliptic, and haak-series cones on student rockets for the Nasa Student Launch.
Geometrically superior for airflow, but often left unfinished and ridged with printlines which can't help their drag much.
How's your success been?
for 29 mm length tubes
When I printed the cone I sanded the printlines out. Also the cones are printed for relatively small tubes
That is too good to be legal.
6 to 1 olgive is my preferred length for rockets. My wife may have a different answer though....
A body tube 1.14 inches long makes for a very short fat rocket, but if you are talking about the diameter of the tube, Apogee makes a nice 29mm nosecone for it's Aspire rocket:
thank you for the recommendation I actually use a very similar nose cone, also from apogee
These made my day.
I have a yet-to-be-realized shape that I like on the screen. It has the parallel sided base of an ogive or ellipse, and the rounded tip of a parabola* or ellipse, but is somewhat sleeker in between than an ellipse. It's just an ogive part way up and a parabola at the top, with the height and diameter at change-over tweeked so there is no corner. It's drag is, I bet, nearly as low as that of an ellipse with the same base and overall height, but looks better. I'd love to get one printed and try it out.
Everyone knows about the perennial nose cone shape science fair project, where several shapes are tested for drag. The maximum gamut shapes tends to be:
Cone, short and long
Ellipse, short and long
Ogive, short and long
Parabola, short and long
Very few seem to do all nine. And we all know that the lowest drag comes from the long ellipse. What I haven't seen, and would like to, is a project that determines how the drag changes with length. Sure, 5:1 is common and pretty good, but what does one actually get with different ratios.
Skip the cone, ogive, and parabola since we know the best comes from elliptical.
Test 0:1 (flat), 0.5:1 (hemisphere), 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, and 10:1.
Plot the results.
Attempt to determine a formula that gives a good approximation (i.e. a curve fit).
Making all those test pieces would have been quite time consuming before the advent of affordable 3D printing, but today this project would be very doable.
*Actually, a paraboloid of rotation, which is typically but incorrectly what is meant when folks say "parabolic nosecone". Actually a power series with the exponent equal to 1/2. But I'll keep using the more usual meaning.
Got base/length dimensions and ideal ratio of ogive to parabola?
I bet I could create some stp or stl files for ya
My favorite nose cone.....I've got two of them and building two upscale Sentinels.
Aerotech Nose Cone - 2.6 in 5/1 Ogive 11261
Thanks, but that's actually the easy part. Getting off my ass to use somebody's printer or convincing myself to cough up the dough to order it from a service is the roadblock.
this is the first result of my 3-d printed nose cone. Any suggestions?
Better lighting for pictures.
Some filling and sanding, probably. Hard to tell.
Slightly longer shoulder, perhaps.
Type of filament? Heated bed? Looks like you have some gaps in the base and just above the shoulder.Try posting that pic and a thread in the 3D printing forum. Someone knowledgeable there can probably help you out.
Trying to imagine this. An ogive with an elliptical tip?
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