Invention Idea

You were already told by experts that it will not work. I suggest that you get a second and third opinion. BTW there is better software out there for 3D than AutoCAD.
Regards,
Boris Mohar
Got Knock? - see: Viatrack Printed Circuit Designs (among other things) void _-void-_ in the obvious place

propulsion." -> propulsion". So what did they say?

I would suggest that you contact your local Small Business Development Center SBDC who are funded under the US Department of Commerce to encourage small business development.
You particularly want to ask about seed money.
Unfortunately, they really have no such money to give you. They may be able to tell you who your local venture capital organizations are. They may be able to tell you what you need as minimum requirements to be considered by anybody for funding.
If you indeed make contact with a venture capitalist (which is almost impossible because they don't ordinarily deal with such tiny amounts of money as there is so little profit and it takes so much time), be sure to present your idea exactly as you have presented it here.
This presentation guarantees that no one will fund you.
The sob story of:
"Genius Turned Down by Experts -- Claim Idea Can't Work -- Fortune to be Made by Willing Investor"
has been overworked and shown to be a fairly predictable loss of investment.
Remember, "Ideas are a dime a dozen" (about 8 cents per idea), and you are asking for $5,000 and all you have is an idea that experts you consulted said won't work.
Uncle Al made a lot of good points in his reply.
It takes much more than an idea --- money usually gets given to someone who has credibility on the technical side, personal resources invested in the idea and either proven ability to manage a project or good fakes to create that impression.
You have a long life ahead of you. Hopefully you will have many more ideas and get into a position to be credible for funding.
I suggest that you take this opportunity to learn the business of inventing and fund raising. There are affordable books, some of which are good.
There are people to meet and learn from, and they probably don't read this newsgroup much or at all.
Good luck.

You seem to think your 3D printed prototype will actually function. Please explain. These things normally generate hunks of laser-cut plastic, nothing more.
Uncle Al covered the rest.
The public needs a basic education in thermodynamics so they stop coming up with crackpot ideas and see through the scams paraded by oil companies and Bush, Inc.