Before jet technology, why didnt engineers ever make propellars?

Question

could pivot in any axis, --via pilot controlled hydralics, say 90deg in any direction --wouldnt that give you ultra-maneoverability? ( i mean mass produced planes, not like a one-off experimental)

Answer 1

Let's look at a real life example.
The Bell Boeing V-22 Osprey has been in development since 1981, and is just now going into service. With its first flight in 1989, the V-22 has been in development for more than 25 years and despite having consumed $20 billion the Osprey program will require another $35 billion in investments from the Pentagon before the program is finished.
The aircraft is incapable of autorotation in the case of engine failure, a fact that led a director of the Pentagon's testing office in 2005 to say that if the Osprey loses power while flying like a helicopter below 1,600 feet (490 m) emergency landings "are not likely to be survivable."
So far, in all the time it's taken to develop, it's killed like 20-30 crew members.

Answer 2

These guys dont have any idea what they are talking about. The reason planes are better than helicopters is that their wings provide lift so much more effectively, thats why helicopters arent super maneuverable even though they have massive props that they can move.
Think of it this way: A wing can make a fighter do a 9G turn using its wings, but if you wanted the trust from the engines to do the same thing you would need an incredible 9 to 1 thrust ratio, which is impossible. There arent even engines that can produce 9 times the weight of the engine, let alone 9 times the weight of an aircraft.
The reason aircraft like the F-22 uses thrust vectoring is that it assists the elevators. The elevators change the angle the aircraft is facing into the wind, the angle of attack, and the increased angle of attack increases the lift of the main wings.

Answer 3

because the force of the the shifting propeller would cause unpleasant or even destructive vibrations on the aircraft.
A spinning propeller will act in the same manner as a gyroscope, so any force applied will be felt 90 degrees from where is it applied. So if a spinning propeller is rotated to the left at 90degrees, the force on the aircraft will be applied on the vertical axis, thus causing massive vibrations, and uncontrollable flight characteristics.
Propellers can never be used in the manner such as a thrust vectors on say a F22 for this reason.

Answer 4

Mainly because of the weakness that would be designed in with the pivot joint. You'd have to make the shaft longer, the prop would have to stick out further, the engine would have to be mounted out further, causing possible problems. Any bearing failures in the joint would be catastrophic to say the least.

So, bottom line, vectored prop thrust was not considered a viable design criteria, it was better to just shift the whole aircraft than use a risky type of mechanical movement. The simpler the better, in flight.

Answer 5

Because the mechanism to actuate the entire propeller would be very heavy and complicated. In order to be strong enough to survive the huge, changing forces and be precise enough to be controlled it would probably weigh as much as the rest of the aircraft, so you would not gain anything. Any possible manoeuvrability gains would be completely negated by the performance loss of all that weight. And can you imagine the nightmare of trying to maintain the thing?

Answer 6

centripetal force. pick up a heavy steel fan when its running and try and move it around, quite difficult unless you go with the rotation. Any attempt to swiwel a running prop would be met with great difficulty. Jets just duct the exhaust gas, not the spinny part.