So I am an aviation neophyte. I’m trying to determine what wing area and torque (propeller based) I would need to generate lift to hover 3000 pounds of carbon fiber (which is about 2 g/cm3 in density)
I’ve tried googling the formulas for lift but I got pretty confused by lift coefficient. Anyone know what that is or how to figure it out? Am I going about this the wrong way? I know propellers are just wings that generate lift through rotation, but is there a different formula for those?
This is out of my area of expertise, but I think you’re mixing up different concepts. It weighs 3000 pounds, you need >3000 lbs of thrust to lift it up. How you generate the thrust doesn’t really matter, apart from the obvious considerations. If you apply, say, 6000 lbs of thrust upward, the object would accelerate faster than, say, 3001 lbs thrust. The propeller is “converting” shaft horsepower to thrust. If you’re buying a propeller, I would guess they’re rated in such a way that would tell you what you need to know.
Thanks! This is all just a minor curiosity started by me getting stuck in a drive-thru line with no escape. I was thinking of how helicopter propellers have airfoil shapes and a coefficient of lift like airplane wings, and wondering if I would experience a loss of lift if I traded the large propeller for several small propellers on the underside, with vents through the vehicle… Maybe I’m forgetting about gyroscopic effects but the outer propellers could be on weighted gimballs for stability… Forward thrust would be provided by air jets.
Or maybe that’s impossible. I know cars already have a lot of overhead in weight from just being able to drive. I imagined a car made of something light like carbon fiber. They’re also shaped really awkwardly and could flip over in the air easily.
I’m not actually making anything with this though, it was just a thought experiment
Helicopter blade dynamics are really strange. When static thrust is straight down works pretty much like a propeller. But once it start advancing is one direction the worlds changes drastically.
The airspeed across the airfoil speeds up in the direction travel and slows down as it retreats. All kinds of pressure changes. And the blade angle changes. No expert, but heard a lecture once at Sikorsky … was convinced Satan involved in all helicopter rotor design and people of honest hearts and pure souls could not do this. (given that, I should have been a natural designer).
A propeller going “straight” into the wind, as it were, doesn’t experience these changes as the prop stays perpendicular to the axis of travel (airflow) so the airspeed over the airfoil doesn’t change as it goes around.
Seems like it would be hard to get onto the two-post lift?
Funded by the tax payer and built by civilian contracts with union labor - it should never break down correct? hahaha
Reminds me of this. I remember watching a documentary/ show on them.
As long as I can remember, at least from early sixties Popular Science and Mechanics Illustrated has had an endless parade of flying cars.
I’m really surprised Elon doesn’t have a model proposed.
This is an iterative process. lets start with three blades, 1000 lb lift each. Helicopters typically have an L/D of 4ish. Assume that you have a linear lift load on the blade, since you don’t have a blade yet. The torque will be 250 lbs times half the blade radius. Note: keep the blade tip speed comfortably subsonic. That will get you to horsepower. After three iterations you should know what you missed. note this is just the starting point in an interesting process.
