Happy New Year to you and your crews, May God bless you all. Thank you so much for your program of videos from TH-cam, proud of you, your great and share for your knowledge.
Have you ever tried a profile for a nozzle that’s based on a CPC (Compound Parabolic Concentrator, or Winston Cone). These are used in optical systems to take 2 pi steradians input on the small end and convert it to +- theta on the large end. Theta being dependent on the design of the CPC. So if the thrust coming out of the rocket (before nozzle) is 2 pi steradians, you can design a CPC nozzle that converts that thrust to a smaller angle, effectively converting the sideways thrust more downwards. Just a thought. I like seeing how things from one field of science can be used in another field. A straight cone is ok, but a CPC would eliminate the need for the converging part of the nozzle before the pinch and reduce the overall length. I’ll try to find some CPC design references for you. Paul
You can CNC a negative CPC in aluminum and then nickel plate it. Pops off with an air hose. Optiform makes them. You can get many out of one mandrel. I’ve made some that are 3” diameter and 400 mm long. Diamond turned an aluminum mandrel in aluminum and NASA electroformed them in a thin shell of nickel. But they used liquid nitrogen to release the nickel shell.
so .if i make a 38mm diametre motor with six 2.25 inches grains with 9/16 inches core and four 2.25 grains with1/2 inch cores,why there is a difference in cores and what may or may not happen if all the six core sizes are 1/2 inches each?
Usually the only reason you would make the core diameter different is so you can put the larger cores on the nozzle end to keep your internal flow velocity down so you don't erode the fuel as much. That sounds like a very long motor, so you might run the risk of having very high velocity in the motor core which is a problem. Large cores are one way to help overcome that.
Hello Minute Rockets, By the way, I accidentally happened upon your video here and by watching it reminds me that I had already purchased Richard Nakka's CD
Thanks! Yes I've been working on a website to make them available, almost done, just been really busy lately. The spreadsheet you can get from www.nakka-rocketry.net/softw.html. If you send an email to minuterockets@gmail.com I will send you the machine drawings.
I love that you get right to it, pure education and learning! This is what I’ve been searching for
Happy New Year to you and your crews, May God bless you all. Thank you so much for your program of videos from TH-cam, proud of you, your great and share for your knowledge.
Thank you for the information friend
Looking pretty good! Can't wait to see this in action!
Thanks, me too!
Nice graphics and put together video...people have been asking me to do an instructional on sugar motors for years.
Thanks! I love watching your videos.
Have you ever tried a profile for a nozzle that’s based on a CPC (Compound Parabolic Concentrator, or Winston Cone). These are used in optical systems to take 2 pi steradians input on the small end and convert it to +- theta on the large end. Theta being dependent on the design of the CPC.
So if the thrust coming out of the rocket (before nozzle) is 2 pi steradians, you can design a CPC nozzle that converts that thrust to a smaller angle, effectively converting the sideways thrust more downwards.
Just a thought. I like seeing how things from one field of science can be used in another field.
A straight cone is ok, but a CPC would eliminate the need for the converging part of the nozzle before the pinch and reduce the overall length.
I’ll try to find some CPC design references for you.
Paul
Hello Minute Rockets,
Very cool. Thank you kindly. I've subbed and liked the video.
Thank you, I appreciate it.
You can CNC a negative CPC in aluminum and then nickel plate it. Pops off with an air hose.
Optiform makes them. You can get many out of one mandrel.
I’ve made some that are 3” diameter and 400 mm long. Diamond turned an aluminum mandrel in aluminum and NASA electroformed them in a thin shell of nickel. But they used liquid nitrogen to release the nickel shell.
Very well done video with great graphics. Now do a real test burn!
Thanks! Yeah, definitely looking forward to testing this one once it's complete. I have videos of tests and flights of similar motors on my channel.
so .if i make a 38mm diametre motor with six 2.25 inches grains with 9/16 inches core and four 2.25 grains with1/2 inch cores,why there is a difference in cores and what may or may not happen if all the six core sizes are 1/2 inches each?
Usually the only reason you would make the core diameter different is so you can put the larger cores on the nozzle end to keep your internal flow velocity down so you don't erode the fuel as much. That sounds like a very long motor, so you might run the risk of having very high velocity in the motor core which is a problem. Large cores are one way to help overcome that.
Thank u
Hello Minute Rockets,
By the way, I accidentally happened upon your video here and by watching it reminds me that I had already purchased Richard Nakka's CD
Awesome, a ton of good info there.
Fantastic series. Can you share your CAD drawings? I’m trying to teach myself free cad
I'm not going to make the CAD files available, but the drawings I used in the video are at minuterockets.com/downloads.php.
any chance we can get this excel book ._.
Love your work! Great to see some awesome design engineering! Are you going to make these spreadsheets and models public? :D
Thanks! Yes I've been working on a website to make them available, almost done, just been really busy lately. The spreadsheet you can get from www.nakka-rocketry.net/softw.html. If you send an email to minuterockets@gmail.com I will send you the machine drawings.
Awesome
When are you going to machine it
It's machined, working on editing the video today.
@@MinuteRockets can't wait to see it!!
Would it be possible to put the plans in the description ?
I'll get them uploaded soon.
Can you make a link for this exel ?
www.nakka-rocketry.net/softw.html#SRM
Can you write the dimensions of the nozel please?
If you haven't yet, check out the machining video, I show the drawing and that has the dimensions.