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-   -   Russian Sa-5 (http://www.oldrocketforum.com/showthread.php?t=17338)

JumpJet 06-20-2018 10:54 PM

Russian Sa-5
 
7 Attachment(s)
It's been a while since I have posted anything scale in nature so I thought I share my latest scale build for NARAM 60. I originally wanted the four strap on boosters to come off once the motors were spent, thus allowing the center portion to continue on its way. Now I know it can be done but I decided to go the safe route and hopefully get a qualified flight and leave the boosters connected for the entire flight. Itís taken me weeks to get these parts grown making MANY changes along the way. Even now I am 3D printing a new nose cone and tail cone since they are a little off. If you look close the fins have steps in them which will need to be primed and filled in to make them look nice. I figured I'll have a good 20+ hours of just finishing work to all these plastic parts before they are nice and smooth.

The four Main Large fins will be built out of a thin plywood center core with balsa sheets on either side, that will be tapered to the correct shape. I will assembling and shaping these wood parts most likely over the weekend. If all goes well NONE of the 12 fins on this model will be glued in place along their root cord. They will instead be bolted in place similar to the real one so there will actually be a gap between the root edge of the fins and their mating surface.

The center body on this model is 2.7" in diameter. The boosters are 1.56" in diameter. Overall length is 38.8". The four booster pods are set up for 18mm motors. I plane on using Estes C6-0 motors in them. For the Center core Iíll looking using an Estes 29mm F15-4 motor. If the model ends up on the heavy side I'll switch out the center motor with a F26 motor. The model doesn't have to go high for the competition, I just need to get all five motors lite and recover the model safely.



Here is a link to a nice video of the SA-5 on the launcher and being launched.

https://youtu.be/NKFqGHlgcI8

John Boren

eljefe 06-21-2018 12:16 AM

Looks like the makings of a beautiful rocket! When can I look forward to seeing it in the Estes catalog? :D

surdumil 06-22-2018 09:43 AM

Very impressive scale project, indeed!
What kind of filament are you printing the final parts with, if I might ask?

teflonrocketry1 06-22-2018 09:53 PM

John,

What model of 3D printer are you using, and what type of filament? Based on your pictures it looks like you are using too high of an extruder temperature and printing at too high of a speed.

JumpJet 06-22-2018 10:54 PM

I'm Using PLA filament. My printer is a Tevo Tornado. I'm new at this home 3D printing stuff. My print speed is 60ms and the temp is 200C.

John Boren

teflonrocketry1 06-22-2018 11:53 PM

Nice 3D printer! I am also new to 3D printing, but have made many hundreds of parts over the last few months. I suggest you use a printing speed of 50ms. I also noticed some of the PLA filaments I own print better at higher temperatures around 220C, you might try increasing the extruder temperature. I have a small BT-20 nose cone design that I print as a test case (30 minute print time) to check the performance of my printers. What slicing software do you use to generate the files for the 3D printer? CURA? Also you might check if there is any play in the printers X or Y axes. If you find any wobble in the bed or extruder platform you need to adjust the eccentric nut on one of the wheels that rides over the v-slot rail on the sliders to eliminate the play. There are so many settings that it is difficult to adjust everything, but once you get a 3D printer dialed in you are usually good to go for awhile. You should look at things like the "jerk speed" (I use 10ms) and if retractions are enabled. I suggest using a filament retraction before printing outer walls. Take a look at the picture in my post on the Estes Python http://forums.rocketshoppe.com/show...736&postcount=2 and you will see the kind of quality you can expect to get from a (cheap $10/kg) PLA filament.

surdumil 06-23-2018 06:49 AM

Thanks, John. I've been messing about with a Prusa i3 Mk2 for a bit less than a year, now, experimenting with different filament materials and manufacturers and print settings. I'm finding there's a whole lot to learn about this field, with lots of potential for building prototypes.

That's an excellent modelling project and it looks like you're getting some great results. I hope that you'll let us know how the project flies (in more ways than one) in the end.

Joe Shockcord 06-23-2018 07:12 AM

Awesome work, "Chief Designer"! :)

JumpJet 06-23-2018 10:05 PM

Wood Fins
 
2 Attachment(s)
Today I build the wood fins for my model. All up weight for the four fins is 4.5 ounces. I still have a little more sanding to do but they are close to being done.


John Boren

JumpJet 06-24-2018 11:14 PM

4 Attachment(s)
Today I was able to finish up the wood fins and make the 40 cutouts in the main body tube for all the attachment points needed. All the parts are simply dry fitted together as seen in the photo. Currently it weighs in at 23 ounces. Also shown is the template I used to cut out all the openings in the tube.


John Boren


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