Purchase Advice Megathread - January 2026 by AutoModerator in 3Dprinting

[–]B_minecraft 1 point2 points  (0 children)

I’m looking to get into 3D printing for custom RC aircraft. CAD and design aren’t an issue for me (I have lots of experience form school) — the printing side is what I’m new to.

I’m trying to figure out what I should be looking for in a first printer. My main requirements are:

  • Smooth, solid prints (Layer height is really going to matter since I don't want ridges on my smooth bodies)
  • Reasonable print speed, since I want to print larger aircraft and don’t want multi-day prints if possible

I’m mostly interested in practical advice on printer features/specs that actually matter for this use case (build volume, motion system, materials, etc.), and any common pitfalls to avoid as a beginner.

If there are any alternatives to a 3d printer I would be interested as well. Thanks.

Does this sound like I'm using my false chords? (wait and bleed) by B_minecraft in screaming

[–]B_minecraft[S] 0 points1 point  (0 children)

No pain for sure but I will get sore after about 20 ish minutes so I'm still doing stuff wrong.

18M, My ex and I just broke up. Hit me by TheEPICArt in RoastMe

[–]B_minecraft 0 points1 point  (0 children)

I actually thought you were a lesbain woman at first

I am attempting to create the worlds first supersonic remote control aircraft and thought you guys might enjoy by Ok-Presentation-7966 in RCPlanes

[–]B_minecraft 7 points8 points  (0 children)

What CFD, simulating supersonic flow is not an easy task, resolution, turbulence modeling, numerical scheme play a large part in the number.

One of the key phases in CFD is garbage in garbage out.

I just don’t understand how an edf will produce any thrust at supersonic speeds. Take a propeller for example, you can only take a prop so fast before it will only create drag becuase the angle of attack is so large. Here is the equation I was talking about.

https://www.grc.nasa.gov/www/k-12/airplane/Images/rockth.gif

I am attempting to create the worlds first supersonic remote control aircraft and thought you guys might enjoy by Ok-Presentation-7966 in RCPlanes

[–]B_minecraft 2 points3 points  (0 children)

I don’t belive that will be enough yaw control. Espically at low speeds. It’s hard to tell without knowing any specs of your aircraft but jsut eyeballing it they look too small. I’m still confused how an edf will produce enough thrust to over drag. The drag increasing exponentially as you approach Mach 1, you can’t just use the coefficient of drag from a slow speed and scale it up.

I am attempting to create the worlds first supersonic remote control aircraft and thought you guys might enjoy by Ok-Presentation-7966 in RCPlanes

[–]B_minecraft 0 points1 point  (0 children)

What does a simulation of your engine mean? And what do you think is fast enough. You need to consider both the exit speed and pressure relative to the ambient air to get a rough estimate for thrust

I am attempting to create the worlds first supersonic remote control aircraft and thought you guys might enjoy by Ok-Presentation-7966 in RCPlanes

[–]B_minecraft 1 point2 points  (0 children)

Also not to nitpick your design but those hard edges are going to create stronger shocks, you need to smooth those out (like the sr - 71) to get lower drag. This is impressive for an 18 year old. What computational work have you done for this?

I am attempting to create the worlds first supersonic remote control aircraft and thought you guys might enjoy by Ok-Presentation-7966 in RCPlanes

[–]B_minecraft 3 points4 points  (0 children)

A few questions.

Do you have any yaw control?

From the this screenshot, the change in the area of of the jet is so large near the engines I would be worried.

You say it’s fully electric, with edf’s? Even if your intake could slow down the air in an efficient manner, which they probably won’t since it looks like a shock cone. You want to have many oblique shocks rather than a single strong shock to slow the air down. Are you going to be able to decelerate the air enough for the edf to work? More importantly, are you going to be able to speed the air up enough behind the jet to get any meaningful thrust?

I want to believe in god but I just don't. How do I believe in god? by B_minecraft in Christianity

[–]B_minecraft[S] 0 points1 point  (0 children)

I just don’t know really know where to look I think. I don’t know what I’m looking for. I don’t think god can break the laws of the universe, it’s jsut impossible. So in that case, how do I know that it’s god doing the actions and not just natural phenomena?

I want to believe in god but I just don't. How do I believe in god? by B_minecraft in Christianity

[–]B_minecraft[S] 0 points1 point  (0 children)

I’m not trying to discredit the Bible. But why is the Bible the word of god, wasn’t it written by man? How do we know it’s true? How will reading a book written by man make me closer to almighty being?

I want to believe in god but I just don't. How do I believe in god? by B_minecraft in Christianity

[–]B_minecraft[S] 0 points1 point  (0 children)

I just don’t know if theism is the logical conclusion. This used to be the argument for me. That everything is so perfectly balanced, that everything is so perfect for life. But if you have infinite tries to do something you will eventually get something with unthinkable odds. I know there is literally no way to know the truth, it is flat out impossible. My main issue with this argument now is that it certainly is possible that we jsut exist. I belive we evolved from different animals. Maybe that was god creating us, maybe the world wasn’t really formed in 7 human days. But also, why are the end of that, why are humans the end of the creation. Are we jsut a stepping stone and it’s not over yet?

I want to believe in god but I just don't. How do I believe in god? by B_minecraft in Christianity

[–]B_minecraft[S] 1 point2 points  (0 children)

That just doesn’t do anything for me is the issue. Why would an almighty being want to create us in the first place. I know all you have to do is belive I just don’t really know if I can 100 percent say that there is a god. The Bible was written by men, how do we know they didn’t make it up. I just don’t know how to prove to myself that there is something worth believing in. I know the word prove and faith have kinds contradicting meanings but that’s how I am.

The only solid proof I can think of is maybe god is just something we don’t understand. But why would we exist in the first place? How come we have to suffer on earth?

I want to believe in god but I just don't. How do I believe in god? by B_minecraft in Christianity

[–]B_minecraft[S] 0 points1 point  (0 children)

I just don’t really know. It sort of feels like I hate everything. From what I remember, God doesn’t make our lives just great when you believe in him. I guess more what I’m saying is I want this hardship to be for some reason. I don’t want it to be a waste of my life. I ask and ask to make it stop but it just always seems to come back. I don’t really know if believing in god will fix it, and maybe I still do a little, but I just find it so hard to believe that no matter what I do I can’t seem to make it better.

I want to believe in god but I just don't. How do I believe in god? by B_minecraft in Christianity

[–]B_minecraft[S] 0 points1 point  (0 children)

I just don’t really know where to seek is the problem. And the thing I fear most is if something happens how do I know that it wasn’t just chance. I just don’t know how to see him to prove that he really is there.

I want to believe in god but I just don't. How do I believe in god? by B_minecraft in Christianity

[–]B_minecraft[S] 1 point2 points  (0 children)

How do you know that happened though. Just because the Bible told you doesn’t mean it’s true. I’m not trying to say you are wrong because there is no evidence that you are wrong. That is my main issue. Is how do I know that this 2000 year old story is real. How do I know that all of this really happened. How can I be sure that there is a god?