Aviation Gurus: What's the hold up with vertical takeoff?
 

I have been hearing the past couple of years about vertical take-offs from the Osprey, the F18 etc. What's the deal with it? Does it work? If so, why don't we employ it more in day to day aviation. Is it too expensive?

Dangerous. The Harrier does it but if the engine coughs on takeoff the airplane is toast and hopefully the ejection seat will get the pilot out of there alive.

Expensive and just not needed. We have enough runways around the world (or carriers) to allow us to use the normal take off mode. Going to VTOL would really cost a lot of funds that we just cannot afford right now.

Joe

we already use it......with helicopters :D

Not to mention it takes a lot more power than most aircraft have. It's a solution for a problem that general aviation doesn't have.

JR

Very true - but do we have a helicopter equivalent of a 747? Military choppers can carry a fair share of weight. What is the longest range of a helicopter?

Good point but would something like this improve overall aviation minus the cost factor.

How exactly would things improve? Aviation is already priced out of the reach of the average guy, for any sensible use. I have friends and family with private aircraft and the costs can't be justified on any rational basis.

JR

My reason for asking is seeing the lack of runway picture in another thread and wondering if it would be an improvement in the sense that you don't need the long runways especially with the aircraft like A380 that are so massive that I assume they would need more runway to takeoff because of the increased weight and size of the aircraft.

I remember hearing that part of the reason they closed El Toro Marine Base here or could not convert it to a regular airport is that everday aircraft (737, 767 etc. ) are too heavy to get over the mountains.

It takes a tremendous amount of fuel to make an aircraft takeoff and land vertically.

Really two different issues:

- The Osprey (which has been in development for over 20 years:eek:) employs the tilt-rotor concept. The concept itself is simple and has been flow in one way or another since the 50's...that I am aware of.
But, like many aviation concepts, the mechanisms for safe tilt-rotor flight is very difficult to engineer on the scale of the Osprey.
I can go into a whole bunch of aero-speak, but the main problems are 6000lb hydraulics, asymmetric lift between the two rotors, which counter rotate, and the fact that it is built by Bell Helicopter, USA, a complete bunch of idiots. I have spent a lot of time in Texas:)

- The F-18 is not designed for vertical take off, the new Joint Strike Fighter is. There have been many improvement in the technology that allows a fixed wing aircraft to launch and recover vertically. My sense is that the Marine version of the JSF (there are three: Marine, Navy and Air Force) will be a huge improvement over the Harrier but many of the same penalties associated with fixed wing vertical flight (additional weight and complexity, additional maintenance, pilot training, etc.) will make the vertical JSF less capable than the Navy and AF version.


Edit: The Osprey is on it's first deployment to Iraq. I hope things go well. The Osprey is a famous case in DoD acquisition, and not because they did well.

The 747 is approaching 1,000,000 pounds (fully loaded). The max thrust per engine is getting up to about 65,000 lbs - with 4 engines that's only 260,000 lbs of thrust total - or about 1/4 of the weight. I can't imagine what the A380 weighs.

It's useful for certain applications, but renders the aircraft heavier and more complex as well as using lots of fuel. The Marine Corp. version of the F-35 is a VTOL configuration. Note the fan for vertical thrush behind the cockpit:

http://forums.pelicanparts.com/uploa...1202660771.jpg

Man, I would hate to be on a huge airliner 150' off the ground hovering when a flock of birds gets sucked into the engine.

complicated, expensive & very high maintenance with minimal return given the equipment that already exists.

It actually uses less runway than 747. Those Welsh boffins made a darn good wing (big too).

There is no point of making VTOL A380. All extra weight/fuel/engines needed to make it lift vertically would make it a fuel hog. It's cheaper to build a runway ;)

Gravity?

http://forums.pelicanparts.com/uploa...1202665245.jpg

Best,

Kurt

I believe the F-35 JSF is a Short Take Off Vertical Landing STOVL.

The Video I've seen you would have to have a big set to clear an obstacle after that takeoff roll.

You are right...my wife worked on JSF for years and I had to go ask:cool:

Then again, the Harrier is considered STOVL as well, at least according to her.

Heh, I'm a H-60 pilot, I don't need no stinkin' STO;)

Simple physics.

Take something that weighs as much as your house, put 150 people on it plus luggage and try to lift it vertically up off the runway.

You'd need a bigger fan than the one in a Formula 1 windtunnel and a nuclear reactor to run it. Wings exist for a reason...

I spent a couple years on the one that lost.