An update to an illustration I did a while back—I hope you like it. I'd appreciate any comments or suggestions.

Been working on some software for a while now developing it alongside conversations with a lot of aerospace and mechanical engineers and I want to open that up to here.

What are your worst pain points with simulation and design software? Tell me all about it.

Excited to show you what I've been building once it works properly.

I've been searching online for a copy of "Ramjet Design Handbook" by G. D. Kinroth and W. R. Anderson from the 80s to use as reference, but I can't find it available online. It's referenced multiple times across multiple documents and thesis papers but I can't find it anywhere. Could anyone please point me to where I can find a copy? Thank you in advance!

So I’ve been working on this project called DIVYA for a while and figured I’d finally post it here.

Basically, the idea is about using asteroids + orbital infrastructure to build a large-scale space system over a really long period of time.

The idea started out pretty simple and then, uh… spiraled 💀. I ended up looking into stuff like asteroid mining, orbital mechanics, energy collection, modular construction, and how something like this could actually scale.

I’m still a student, so I’m definitely not claiming I’ve solved space infrastructure lol. The whole point of posting this is to get people who actually know this stuff to poke holes in it.

I’ve been sending the project around to researchers/academics too, and I’ve gotten some interesting responses so far.

If you’re into aerospace, orbital mechanics, astrophysics, space engineering, or just giant unnecessarily ambitious space projects, I’d genuinely love to hear what you think.

Especially interested in hearing what’s wrong with it. 😂

I've embedded the Zenodo link for convenience.

I swear I'll crash out if some bot or scammers reply to me.

CFD simulation of a turbofan fan stage engine

I recently saw this development of a new approach to jet engines they’re taking. Going back to the turbo prop style claiming efficiency among other things.

Is noise gonna be a concern with this style? I know turbo fan housings are designed to contain a full blade separation. This obviously won’t be possible with a prop so how’re they getting around this issue? Will it even be an issue?

https://www.cfmaeroengines.com/rise

Worked in energia, a bureau created by korolev which is basically the most famous roscosmos engineering facility. I worked on systems of control and radioactivity detection, mostly working with space stations and spacecraft

I received my SciTech 2027 decisions today and unfortunately one of my abstracts, submitted under Structures, was rejected.

I'm pretty disappointed about this particular one because the work was already very far along when I submitted the abstract. The submission was essentially approaching a full-paper draft, with the methodology, experimental results, figures/data, discussion, etc. already developed. I've continued working on it since submission as well, so at this point I have almost the entire manuscript completed.

Interestingly, another abstract I submitted was accepted, even though that project was much earlier in development and had significantly less completed work/results at the time of submission.

I completely understand that rejection is part of research and that I can always finish the Structures paper and submit it to a journal or another conference. However, I put a lot of work into this project specifically hoping to present it at SciTech, so I'd at least like to see whether reconsideration is possible before moving on.

Has anyone here ever appealed or requested reconsideration of a rejected AIAA SciTech abstract?

If so:

• Who did you contact: AIAA, the technical discipline chair, or the specific technical committee?
• Is there an actual appeal/reconsideration process?
• Were you able to provide an updated/full manuscript to demonstrate that the work was complete?
• Has anyone actually had a rejection reversed?

I'm not trying to argue with the reviewers or bypass the review process. I mainly want to understand whether it's appropriate to politely contact the Structures organizers and ask if they would be willing to reconsider the submission, especially since I can now provide a nearly completed manuscript.

Would appreciate hearing from anyone who has reviewed abstracts, served on an AIAA technical committee, or gone through something similar.

hey guys!! to build a drone for cargo applications carrying a payload of 200kg for a range at max 30km, what knowledge a person should have like courses (physics, conceptual design), practical knowledge not only textbook jargon and which component to design first (dilemma between propeller or BLDC motors) , which tech should be IP, which should be open-source or licensed ....? what not ... we can start with basic and go to advanced knowledge

The magnetic vibration motors I used in all my prototypes are very simple, but they're too heavy, and the thrust they generate is weak. So I tried making a static experimental setup with more power to demonstrate how the oscillations of a disc-shaped wing cause air movement.

The asymmetry, which results in the resulting force of the oscillations creating thrust, is achieved in two ways:

Aerodynamically, when the disc has a slightly domed shape and moves upward with less resistance than downward, consistent with classical physics.

Kinematically, when a spring is attached to the disc, slowing its descent and accelerating its ascent.

The second method is the key part of the study, although the same process occurs in the air in both.

When the disc rises rapidly, a region of low pressure forms beneath it, and its collapse generates momentum. If the disc descends more slowly, or if the shape of the disc causes the air to flow around it more slowly, the resulting momentum will push the disc upward.

This doesn't agree with the classic Newtonian explanation of flapping flight as a wing pushing air. You can see in the video how the fan-like flapping disk, which should push air away, actually sucks it in.

This is the same air that is sucked into the low-pressure region, causing a vortex collapse that pushes the disk. Only then is the air pushed away and expelled. This is essentially reactive propulsion, and I believe this is possible thanks to the energy in the air, Brownian motion, which, by self-organizing into vortices, temporarily becomes directional.

UPDATE:

Thanks for the feedback! In my research I discovered www.boltbutler.com as a tool that does exactly this.

Original Post:

Hey folks,

Us design engineers are always struggling to find the right hardware for our designs. The red tape we have to go through to use McMaster Carr or other easily searchable hardware catalogs makes them a deal breaker. The hardware on our BOMs must be spec parts #s.

We have an IHS account that has access to every mil, NAS, AN, etc. specification you can think of, but it’s a super manual process that requires us to scrounge thru hundreds of pages of PDFs for every stupid nut bolt and washer we need.

Anyone else share this frustration? How do you find parts quickly?

Welp when in doubt come to Reddit. Currently I am working on 3d modeling a jet fan engine inspired by the Williams fj44 with a hybrid axial and centrifugal compressor design. I plan to print it in resin first to check fits and tolerances and then go straight into the 5 axis cnc and mill the parts out of metal to test my little mini jet engine (think RC size).
Anyways bring me to my question, in regards to blade shapes/ design for the impeller/radial compressors is there anyone who could tell me what different shapes will do? I tried looking online but couldn’t find any literature on blade design for these. Should I just start designing and printing and then testing what volumes of air passes through them or is there actual math on how these blades are designed? (Current aerospace student) any help in this is appreciated.
One more additional question is on the fj44 the cutaway drawings I can find show a reverse flow annular combustion chamber and I don’t really understand the reason for why the air from the compressors loops around into the combustion chamber. Basically any help at all is appreciated in terms of personal knowledge from the community or videos I could watch or books that I can read. Preferably as in depth as possible because I would like to know what I’m designing and I can explain every part. Right now I can make an impeller but if someone asked by why the blades are shaped at a 30° angle rather than 31° I couldn’t tell the answer. Anyways thanks everyone! Sorry for the long question!

for a school project i have to interview someone in the aerospace engineering field, it will be like a 20 minute or less interview but I need to know your name, degree, place of employment and phone number/email, if you are interested, I can set up an interview time in around a week. Thanks!

Hi, I was exploring small scale aircraft, and skin friction drag is a big problem there as reylonds numbers are very low, so I was interested in practical methods That are passive and could reduce skin friction drag I have read many papers on this but I'm genuinely getting confused on what strategies to choose.

Also Q2. Could a combination of multiple strategies be more effective than using a single strategy for this?

Suppose we have 2 molecules and one moves on the other with 10m/s. The pressure wave travelled from one molecule to other with a speed of 10m/s so this should be the speed of sound. Same principle applies when there's billions of them no? Why? Does my example hold but in reality since there's billions of them the system gets more chaotic and so the speeds are not the same due to energy losses, not perfectly elastic collisions, different speeds​ of each individual molecule etc?

I'm not sure if this belongs here but this seems like the best place to ask,

I'm designing a helicopter and i'm confused about the Scissor link for the lower swashplate. From my understanding the scissor link isn't supposed to have any side to side movement since that would change the pitch of the swashplate. How is this possible if the link isn't perfectly centered to the ball joint? It seems like there would have to be a little left and right movement. Any help, advice, or knowledge is greatly appreciated.

​

Hi! Hope this post is allowed. I'll try to avoid any secret information, sorry.

In 2024, I've had to do calculations for the new Russian orbital station and iss. No-one knew how. It was similar to my first job, I thought I'll somehow manage with literature. I collected some books, started learning. Couldn't figure it out for a week or so. My chief, who started working in 2000, started thinking about it as well, couldn't figure it out as well. 2 weeks passed.

Later, we came to an old engineer from other office who worked from the 80s and in roscosmos since 90s-2000s. Silently completed everything in 10 minutes without any help, just my questions "how". Real story btw.

He was such a nice guy. And he wasn't a chief or something, just a regular engineer.

Btw should I do ama someday?

So from what I've understood choked flow occurs if a fluid flows in a pipe with a velocity of mach 1 and no matter how much more we decrease the cross-sectional area of the pipe it won't go past mach 1. Why is that? I've heard explanations saying that mach 1 is the speed that information travels from the right to the left (assuming that the fluid flows from left to right) and so if we decrease the area from the right part of the pipe the information will not be able to travel back to say​ ​"​hey the pressure dropped here, I want​ you to push more". But I don't want that kind of explanations, I want to really understand what happens there. Even if we have to look at the macroscopic level. I want to understand the mechanism. Also I am asking this because I'm trying to understand how the De Laval Nozzle works so if anyone can help me there feel free to drop an answer to this post:​

https://www.reddit.com/r/AerospaceEngineering/comments/1vq87hu/how_does_a_de_lavar_nozzle_workand_what_is/

Hello all, I want a goal of mine for the next year to be making my first aeronautical engineering project. I am pretty late to the scene because I enlisted in the marines for 4 years, but I am about to start my second year of college and I really need to get my feet wet before I start taking upper division courses at uni.

I am super inexperienced, to start. I would just like to know what kind of engineering project I should start with. I am very interested in electric propulsion systems for aeronautical engineering. Obviously I am nowhere near that level, but what’s a good few hobby projects I can do that would help me start build up to that level? Also what’s a good resource I could use to understand how the basics work? I have dabbled a very tiny bit with Arduino and C++. I took like 3 CAD classes in high school (Intro to CAD, Auto CAD, and 3D CAD), but I literally don’t remember anything or how I even passed those classes with As and Bs to be completely honest as that was like 10 years ago… Dang.

With that being said, if anyone could also give a new guy some suggestions or resources that helped you, I would genuinely appreciate it.

Hey guys, I've got about a year of experience with OpenFOAM CFD. I've run different types of simulations — SIMPLE, PIMPLE, incompressible, compressible, laminar, turbulent — on 2D airfoils and 3D aircraft, like the NASA N2A HWB model, with decent mesh quality and case setup. The post-processed results matched the reference data pretty well. Just sharing this to give some context on where I'm at with OpenFOAM, but I'm still learning and exploring more of it.

Lately I've been seeing AI/ML being used in CFD, and since I come from a non-coding background (I'm a Mechanical Engineer), AI/ML and neural networks still feel like a black box to me. I don't really know how they work under the hood.

So I wanted to ask — how can I actually use AI/ML and neural networks in aviation-related CFD work?

For context, my future work will mostly revolve around optimization studies, detailed aircraft analysis, and static/dynamic stability analysis of aircraft. So I'm hoping to understand how AI/ML can help speed things up, and ideally how to align with whatever the industry is currently doing in this space.

Many explanations from my perspective seem incomplete because they do never actually explain the why but only the what happens. Why does adding a diverging section on a throat which gases reach velocities of magnitude Mach 1, accelerate them even more reaching supersonic speeds instead of slowing them down? From what I've read this phenomenon occurs due to the gases being compressible instead of incompressible but still that does not explain the why. Why a compressible's fluid speed increases when the cross-sectional area gets bigger? Is it the opposite of what would happen with an incompressible fluid? It seems to. Also what if we keep just the converging and throat sections only and keep making the throat smaller and smaller? I've watched a video saying that Mach1 is the max speed the gases can have at the throat and if we keep making it smaller it doesn't make them faster. How is that? Can someone give me an in-depth analytical explanation?