A different type of hybrid car

Uh... will never happen.

It will need FCC compliance. And a flying license.

The only thing that company is good for is to drain investor money.

 

<div class='quotetop'>QUOTE(dipper @ Mar 21 2007, 03:18 PM) [snapback]409710[/snapback]</div>

Do you mean FAA? :huh:

 

Ah yes, the flying car revisited. Autogyro technology is, perhaps, more suitable to the idea of a flying car than a conventional wing, tail and vertical stabilizer which would have to either be folded up into the machine for road use, or detachable.

There are myriad problems with trying to make a roadworthy machine fly....or, put another way, make an airworthy machine safe and roadworthy. The most obvious problem is weight. Like birds, aircraft need high strength and low weight parameters; birds do it with hollow bones and airplanes with aluminum, glass reinforced plastic or fabric over steel tubing. None of these is suitable for the rough and tumble world of an automobile, and while a Cessna is more than sturdy enough for movement through the air, one would not want to try a 30mph head on collision in one with a Ford Excursion.

A flying machine sturdy enough to be safe on highways would weigh too much to have any kind of useful load in flight mode.

The locations of the centers of gravity of an airplane and an automobile are in very different places. Making a vehicle that is safe on roads and highways generally ends up with a center of gravity that would not work well if you were to try and make the machine fly. An aircraft rotates about three axes, which pass through the center of gravity. Movement around those axes are caused by control surfaces being deflected into the slipstream of air passing over the aircraft. The distance from the center of gravity to the specific control surface determines how effective that control surface will be. If the center of gravity is too far aft, the aircraft will have a tendency to lift its nose; with a fixed wing, this could cause the airflow over the wing to break up causing a loss of lift. If the center of gravity is too far forward, there might not be enough "control authority" to lift the nose, in which case the machine would never become airborne.

Rotary wing aircraft have much smaller fore and aft limits to their centers of gravity.

Notice among the photos, there is none of the entire machine; especially of the folding rotor. Either these guys are blowing smoke out their rears or they are trying to protect some as yet unpatented system. Rotating wings are complex items; making one that also folds for storage adds more cotter pins, and increases the risk. Contrary to the statement in the ad, engine failure in a rotary wing aircraft is a serious problem and I don't think the average pilot-driver will simply autorotate to a safe landing in some football field. Rotor failure is usually a non-survivable event.

No doubt, these guys will probably get something that will work through the first stages of development, but they will have to deal with both the FAA and relevant motor vehicle agencies in order to get something that could be put into production. Without FAA certification, (a process that can cost millions and take years) they will have a machine in the "experimental" category that may likely be barred from flying over urban areas.

There are too many errors about airspace, pilot licensing and aircraft technology for me to take these guys seriously. Gotta give 'em credit for creativity, though.

To date, there have been five flying car concepts developed in any depth; only one of which led to an actual flying car and that never went into production for the above reasons.

Bob Allen, Certified Flight Instructor

 

<div class='quotetop'>QUOTE(Ethereal @ Mar 21 2007, 03:53 PM) [snapback]409824[/snapback]</div>

:lol: Brain freeze. That is what happens when you work too much.

 

<div class='quotetop'>QUOTE(Angel Flight Pilot @ Mar 21 2007, 07:30 PM) [snapback]409925[/snapback]</div>

Please note that I'm also somewhat skeptical of the Pal-V. At the same time, the analysis you provided above seems to be comparing airplanes or helicopters (what I assume you mean by rotary craft) to autogyros, which does not seem like a fair comparison after reading the Wikipedia article on autogyros.

Is weight truly an issue? Aircraft such as airplanes and helicopters have been designed to be in order to carry massive loads such as many passengers w/ luggage or ground vehicles (including tanks which are probably much more dense than anything a passenger vehicle would have to contend with and definitely not light). Obviously such aircraft are designed to be light themselves to increase the weight that of their liftable load.

Also, rotary failure being a non-survivable event seems to assume an aircraft like a helicopter where the lifting rotor is powered and that rotor failure is equivalent to loss of lift. An autogyro's lifting rotor is actually not powered and driven purely on aerodynamic forces. I'm don't understand exactly how it works (there is some analogy drawn to hang gliders), but several websites document that if the rear rotor fails an autogyro will slowly and safely descend. I can sort of visualize it behaving like a toy twirlybird (the wooden propeller on a stick toy).

I definitely am a novice regarding aircraft in general. You have some expertise in airplanes and possibly rotary craft but does that expertise also apply to autogyros? It seems to me that autogyros have a different set of constraints compared to airplanes and rotary craft.

Having said that, the Carver One upon which the Pal-V is based itself is a pretty interesting vehicle, despite not being airworthy.

 

<div class='quotetop'>QUOTE(lowlander @ Mar 22 2007, 12:04 PM) [snapback]410325[/snapback]</div>

Awesome... thanks for the link!

 

<div class='quotetop'>QUOTE(ryogajyc @ Mar 22 2007, 05:14 PM) [snapback]410537[/snapback]</div>

Better yet... go to www.flytheroad.com and look at their videos. More Carver videos. And This company is planning to do a Carver like car. Except the spin is with hybrid and EV. And a lot cheaper... I hope.

 

<div class='quotetop'>QUOTE(ryogajyc @ Mar 23 2007, 02:53 AM) [snapback]410316[/snapback]</div>

The FAA examiner who issued my private pilot license some years ago was an airline pilot flying the Boeing 727. He remarked that he felt safer in small planes than he did in his 727 for a simple reason: As you increase the velocity of an object, you increase its energy potential. To protect the passengers in a Cessna weighing one ton, from an impact landing at 50 miles per hour requires hugely less structure (i.e. weight/mass) than would be required to offer the same level of protection to passengers in a 727, weighing 200 tons from an impact landing at 140 miles per hour. There is no way you can exponentially increase the crash resistance from a Cessna to a B-727 without the 727 weighing so much as to be unable to fly at all. My point is that the "crash / accident" environment for a car is very different than for an aircraft because they operate in very different environments. Airplane crash resistance is predicated on the emergency landing scenario, whereas a car is designed for the possible head on collision of two vehicles on a highway. Think about it.

Any airfoil can stall whether its a wing, a rotor blade or a jet engine turbine blade. When an airplane wing stalls, the wing stops developing lift and the nose drops. When that happens (assuming the pilot isn't trying to keep the nose up in a panic mode) the wing resumes developing lift. When the engine stops in an autogyro, the rotor will continue to rotate, but the pilot needs to act quickly to keep it rotating. And yes, an autogyro is safer than a helicopter because its rotor has many fewer moving parts, but it is not as safe as an airplane because, with an autogyro, the "thing" that keeps you up is rotating and thus more prone to failure than the fixed, unmoving "thing" that keeps you up in an airplane, the wing. An airplane will fly better and further without engine power than will an autogyro.

The biggest impediment to the flying car has nothing to do with physics or aerodynamics. It was hinted at in previous posts: air traffic control and airspace limitations. If the flying car is to have a chance in the market place, it would need to have at least as much functionality as a private airplane, i.e., the ability to go from city to city. I think it highly unlikely that the FAA would ever agree to adding "flying commuter cars" to an already crowded airway system.

 

<div class='quotetop'>QUOTE(dipper @ Mar 21 2007, 12:18 PM) [snapback]409710[/snapback]</div>

Last I checked, the FAA has no jurisdiction over the Netherlands -- where this vehicle was created.

We may never see it in the States, but maybe some rich guys over in Europe will have a couple.

Nice idea ... but the cost would be too great at the moment.

 

Thanks, Bob, for your analysis. I'd like to highlight a couple of points and ask for your comment.

<div class='quotetop'>QUOTE(Angel Flight Pilot @ Mar 21 2007, 07:30 PM) [snapback]409925[/snapback]</div>

It's clear from the videos that this vehicle is based on a motorcycle. Hitting or being hit at 30 mph on a motorcycle could easily be fatal, but people ride them all the time. If you forego the ultra-strength steel cage I am happy to ride in in my Prius, you might get a motorcycle light enough to fly.<div class='quotetop'>QUOTE(Angel Flight Pilot @ Mar 21 2007, 07:30 PM) [snapback]409925[/snapback]</div>

It appears that control of the PAL-V is effected through rotor angle, so the lifting surface is also the control surface. If the rotor hub is located above the horizontal (fore/aft/left/right) center of balance, in stable flight the vehicle will hang below, level.<div class='quotetop'>QUOTE(Angel Flight Pilot @ Mar 21 2007, 07:30 PM) [snapback]409925[/snapback]</div>

I suspect they are protecting their design. There are some hints though. The rotor blades telescope. In operation, centrifugal force will keep the blades extended. Since steering control is from the hub, I bet it uses a system a bit more sophisticated than cotter pins.<div class='quotetop'>QUOTE(Angel Flight Pilot @ Mar 21 2007, 07:30 PM) [snapback]409925[/snapback]</div>

In the summer around here I sure hear a lot of chainsaws in the sky. Ultra-lights and autogyros are sports vehicles, much like a motorcycle. A lot easier to get killed in one than in a Cessna, a 757, or a Prius.

Regarding air traffic control, addressed in a different post, the PAL-V web site suggests that there is no problem as long as there aren't many in the air. This is the situation now with ultra-lights and autogyros as sport craft. They plan on the NASA Highway in the Sky concept, based on smart autopilot spacing using GPS and radar. Our current ATC system can barely handle the traffic now, so some form of automation of ATC is almost inevitable. Maybe we'll have flying motorcycles when we have auto-ATC.

 

<div class='quotetop'>QUOTE(lowlander @ Mar 21 2007, 02:21 PM) [snapback]409665[/snapback]</div>

I would have to agree with the other posters, there are great ideas espoused here, but most of them will never see the light of day.

Check out www.moller.com.

They have been working for years to get theirs "up" and still have never reached the market.

Lots of ideas, no real products.

 

<div class='quotetop'>QUOTE(Angel Flight Pilot @ Mar 23 2007, 08:01 PM) [snapback]411299[/snapback]</div>

This still suffers from being an apples-to-oranges comparison. I have seen no indications from various autogyro sources will crash at high-speed after engine failure. Instead it will settle like a parachute which means landing without harm and without the need of a protective structure.

<div class='quotetop'>QUOTE(Angel Flight Pilot @ Mar 23 2007, 08:01 PM) [snapback]411299[/snapback]</div>

The pilot doesn't need to do anything to keep the rotor rotating. Acting quickly actually is cited as a common problem with fixed wing pilots who pilot autogyros. Unaccustomed to the lag between control and response, pilots will cause Pilot Induced Oscillations or Power Push-Over (the latter of which is unrecoverable). In addition, there have been several badly designed autogyros which have been unstable. The general consensus is that with a properly trained pilot flying a properly designed autogyro is safer than a helicopter or airplane.

If the engine fails, the primary and universal concern is avoiding Sudden Decceleration Trauma. Flying further without engine power is a secondary issue and only situationally useful if the area you are above isn't safe to land.

<div class='quotetop'>QUOTE(Angel Flight Pilot @ Mar 23 2007, 08:01 PM) [snapback]411299[/snapback]</div>

The idea seems to be to fly below commercial airspace. In addition, an autogyro is Short Take Off and Landing, which means you don't need a traditional large airfield/airport to take-off and land.

<div class='quotetop'>QUOTE(Bill Merchant @ Mar 30 2007, 03:55 AM) [snapback]414767[/snapback]</div>

The BMW C1 may be a better comparison for safety. It is an enclosed motorcycle which has the crash safety of a small car. I think extrapolating safety from the C1 for a PAL-V/Carver One (which appears to be the basis for another BMW vehicle) would be more accurate.

<div class='quotetop'>QUOTE(faith2walk @ Mar 30 2007, 06:12 AM) [snapback]414799[/snapback]</div>

The Moller SkyCar is a Vertical Take Off and Landing airplane, which appears to be a very difficult problem as the commonly known VTOL airplanes are the Harrier, the YAK-38, the JSF, and the Osprey. VTOL is complex as shown by the above examples. The YAK-38 didn't work that well, and the Osprey has been/was under development forever now (with some tragic accidents during development). There are definitely others, but those are probably the most well-known.

If you watch a video of the SkyCar, you'll see what I mean by unstable. I wouldn't feel safe bobbing around in that thing.

In comparison, the Carver One has been demonstrated (see above video). Autogyros have been demostrated as well. You can buy an autogyro kit and build one yourself! Putting the two together is not nearly the stretch required to develop a personal VTOL airplane.