Jet engines are powerful enough to haul giant aircraft through the skies. But you can’t use a jet engine on a roadway.
Hovercraft engines are indeed very powerful. That is an advantage in some ways and a disadvantage in others. What you are continually refusing to consider is that a balance of forces is always necessary and that balance may not be forthcoming in some particular instances.
They’ve changed but not that much. And to get a large force, you have to move a large quantity of air. A helicopter has a huge rotor moving a huge mass of air. To get the same force with a ducted fan of much smaller area, you have to raise the fan speed. That adds noise, and eventually you run into physical limits with the blades and aerodynamics (supersonic tip speeds, etc)
Think about a thrust-reversing jet engine. That’s the ultimate in using air to manoever with an engine. And while very powerful thrust reverser can slow a jet fast enough to feel like wheel brakes, it’s not only a huge amount of power, but it all goes in one direction. On a hovercraft, you can’t have a separate engine mounted in every direction, so you need ducts or vanes to redirect some of the engine power in the direction you want to oppose. That takes time, and only so much power is available since the fans still have to maintain lift.
Airplanes do not change direction easily. A Cessna 172 going 110 kts and banking 60 degrees will still require 621.9 feet to turn 180 degrees - at a more reasonable 45 degree bank angle, it needs a quarter of a mile! You don’t typically notice this in an aircraft because you are at a high altitude, but when you’re low to the ground this is a serious problem and many pilots have been killed trying to make a rapid 180 degree turn back to a runway after a problem with their engine. The distance required to turn is much greater than they imagined, and they increase the bank angle to compensate and stall/spin into the ground.
The lack of manoeverability is one reason why pilots of aircraft prefer to have as much altitude a they can get, and why flying through mountain passes can be so hazardous.
And think of what an airplane is doing when it is banked - it’s very rapidly directing a large amount of its lift against the direction of travel. A tight bank can result in an acceleration of many G’s - much higher than a hovercraft engine would ever be able to provide. And yet turning is still a ponderous business.
The landspeeders in Star Wars somehow “grip” the terrain under them so they don’t slide around like an air hockey puck. Look at the pod race in The Phantom Menace, where getting broadsided only shoves Anakin’s pod a few feet. There’s nothing like that in real life.
So the problem is the fans or air intake would have to be way more powerful to fixed this manoeverability problem.
And we don’t know how to make fans or air intake more powerful.
Other possibility for this manoeverability problem is not to use fans or air intake but to use like a smaller jet engine built for landspeeders.This could be very powerful.
With these smaller jet engine landspeeders and Moller Skycar may be possible.
Jet engines are very inefficient at low speeds. Propellors/fans are far more efficient. But the ultimate problem is that you are moving through one medium (the air) while trying to navigate with reference another medium (the ground). While that works in a broad sense for helicopters and aeroplanes, it becomes difficult and stressful when you are trying to do it at a small scale (following roads or road like features) for a long period of time and when the consequence of getting it wrong is injury or death.
That is why I said it would have to be scale down jet engines.
At preset fans/ propellors are not powerful enough to make sharp turns and turn on the dime thus need lots of room for manoeverability.So on the road it would need very big lanes for manoeverability.Well jet engines are too manoeverability so when you make turns it too forceful.
That why I said for this to work they would have to scale down jet engines or make more powerful fan/propellors.
Jet engines are inefficient at low speeds. It doesn’t matter how big the engine is. And a small engine has a lot less power than a big engine. Also jet engines are not particularly great for changing directions etc.
But that is what I said.The problem with fans/ propellors they are not powerful enough and because of this can’t make sharp turns and turn on the dime thus need lots of room for manoeverability.
And the problem with Jet engines is they are too powerful thus too manoeverability it like being in car turning the steering wheel to the right a bit but it like some one turn it all the way to the right .
The only solution is to make Jet engines less powerful so manoeverability is right or make fans/ propellors more powerful so manoeverability is not a problem.
That is what I was trying to say.
No, the problem with jets is not that they are too powerful. Jets are inefficient at low speeds and low altitudes. They use a lot of fuel to do not much.
The best way to manoeuvre something that is very close to the ground is to extend some kind of grippy rotating device so that it contacts the ground and can use the massive amount of friction between it and the ground to change directions.
I know what you mean, Richard; Jetires!
Just have each wheel powered by a jet engine with the shaft made of rubber.
Actually, if the problem is that jet engines are not efficient enough, we could have a jet engine use fuel to heat air which would boil the water in a steam engine* which would spin a turbine to make electricity. Now, this would make it an electric hovercar. Electric cars are efficient. So, that would take car of the inefficiency of jet engines.
See, all we have to do is make them electric hoversteamcars.
I don’t know what kind of pilot you are that you didn’t see that. I guess kangaroo pilot licenses have a lot in common with kangaroo courts.
Can you elaborate on this.This is what I think I’m confused about.
This thread is getting little bit frustrating. We have 19 posts above talking about manoeverability ,jet engine ,fan and air intake but seem to be messing real question every time.And despite I have ask many times.
May be it is grammar or miscommunication problem.So I will rephrase the question and hope the answers are direct as possible.
We have manoeverability problem because fans/propellors are not powerful enough? If that case we would need stronger fans/propellors? If that is possible.
very important.I need to understand this.I ask this way too many times in this thread.
Is it even possible to make a stronger fans/propellors?
We have manoeverability problem with jet engines ? Still don’t why here.
If I understand we cannot make jet engines less powerful or scale down the jet engines.
The maneuverability problem are because changing your direction by pushing against air does not work even remotely as well as changing your direction by pushing against the ground. A vehicle that accelerates and steers by pushing against the surface of a road with tires will be able to control its speed and direction much more easily and effectively than one that uses jets or fans to push against air. This is because ground is solid, and air is not. Try sitting in a good office chair and pushing yourself across the room by pushing against the floor versus pushing yourself across the room with a fan. The problem isn’t the power of the fans or propellers, but the difference in the medium you are using to push against.
AndrewL he was saying fans/propellors take a long time to turn and don’t turn on the dime!!
So it seem it if the fans/propellors are more powerful it would turn faster. If it is even possible to make it more powerful.
What you are describing like in above like in space or the air is a inertial problem. You say I want to go little to right.You blast some air and start to go to right:eek::eek: But you find the craft still is drifting to right.You try to blast more air to stop it, but now find the craft drifting to left too much.So you are finding with inertial problem.
But this with strong jet that turns on a dime but has problem with inertial.Only way to fix that is to have computer always adjusting it self.So every second blasting to left and right to maintain that lane.But are computers and jets are probably nowhere near that level today.The computer AI would also have to take in wind speed and calculating it with adjustment.
It is no different when trying to swim in water or boat on water you are fighting with inertial with current.With larger current inertial because a problem.
If HOVercraft are so fuel inefficient, why do they get a special lane reserved for them on the highway?
We have planes ,boats and helicopters that run on fuel so why would landspeeders have problem with fuel.
Here is Hover Car - Prototype being built in Israel and better first one.