A New Rotorcraft Concept

[Chuck Baltzer]

Hey guys, its been a long time since I’ve posted on the Rotary Conference, but I’ve been thinking for some time about an idea for a new kind of vehicle that I am hoping to get some opinions on- here on the conference.

Here’s the idea: Suppose a builder made a two seat, open-frame, coaxial rotor blade vehicle- this would look, of course, like a homebuilt, experimental, double-bladed helicopter (think of the Air Scooter with 2 seats, www.airscooter.com). But here’s the difference: This vehicle would be restricted to “flying” just 10 feet above the ground- in other words- it would technically, and legally, be a hovercraft.

The laws governing hovercraft state that a hovercraft can “fly” up to, but no higher than, 10 feet above ground level. A rotor-bladed craft could be restricted from flying higher than 10 feet by way of several methods: 1) Electronically- by programming an onboard computer to restrict altitude to 10 feet. 2) Mechanically- the craft could be constructed without the ability to achieve an altitude higher than 10 feet. 3) Legally- by virtue of the fact that the operator of the craft obeys the law, and maintains an altitude of 10 feet or less while operating the craft. (Many things are regulated in this world by people simply obeying the law(s).

Ok, so at this point, you’re wondering what on Earth is the point in building something that looks like a 2-seat, open-air helicopter that can only go up ten feet? There are several reasons- and they’re all actually very compelling.

The first, and most important aspect of this concept is to understand that it is a novelty vehicle. Think of small homemade hovercrafts- they are more of a novelty than anything else- they have very little practical use, save for recreational purposes. The same might be said of a go-cart, snow-mobile, motorboat etc.

However, what would the demand be for such a vehicle as the “rotor-bladed hovercraft”, if such a vehicle were being manufactured and sold? The demand would be very high. Here’s the reason I believe this to be true: Think of how many potential homebuilders and wanna-bees you’ve heard of- in real-life, and on these conferences. Think of the people that would love to purchase an already-built vehicle, for extremely low cost (relative to any kit or factory manufactured vehicle). And think of how many people would like to take advantage of being able to own and operate this vehicle without any requirements for training or licensing.

It could be a hobby for the hovercraft-type of enthusiast, a (float-equipped) recreational vehicle for people with camps on lakes, an inexpensive tool farmers could use to maneuver around their property boundaries, a go-between for people casually interested in aircraft but don’t have, or don’t want to spend, the large cash price for even the lowest priced aircraft, a father-son project, a low-priced educational project etc.

And where could this “rotor-bladed hovercraft” be used? Equipped with amphibious floats, it could traverse lakes, fields, marshes, bogs, wide river beds, plains, prairie, abandoned level lots, mud flats, shorelines, and anywhere there is enough open space to clear the rotor blades.

It seems like it would be useful as a reconnaissance and search and rescue vehicle along shorelines in such places as the U.S. Great Lakes, and in desert regions, such as those in the western U.S.A. Another possibility would be border patrol along the extensive U.S.-Mexico border.

In short- it could be used for whatever the owner would like, as long as he has sufficient open area in which to operate. This type of a vehicle would be highly trailerable- an easy hop on and off- and so I would imagine that these crafts would be trailered to many locations just as routinely as hovercrafts and boats are.

The cost? Since this vehicle is not an aircraft (although it would resemble one), but rather a hovercraft- then none of the aircraft, nor ultra-light, rules would apply. Hovercrafts can be manufactured, already built and ready to use, and sold by anybody. I have estimated that in my (family owned) metal fabrication and welding shop, I could manufacture and sell a craft of this type for under $10,000.00, and probably a lot less as soon as fabricating parts for this craft becomes more standardized (remember- this is NOT an aircraft- it’s a hovercraft).

I would fabricate simplified (but still VERY high quality) parts and systems, such as a simplified coaxial rotor system, fixed-pitched rotor-blades, and 2 seated airframe. And then I’d acquire a low cost, low HP, non-aircraft gasoline engine for the vehicle.

And so, the question I’m putting out there, for you guys to (hopefully) respond to, is: If this vehicle- a “rotor-bladed hovercraft”, that looks like a 2 seated homebuilt helicopter, that can only fly up to 10 feet maximum altitude, and is intended as a hovercraft, NOT an aircraft, then is there any law or regulation that would stop it from doing so?

Simply put- is it legal to make, sell, and operate, a hovercraft that looks like a little helicopter?

[karlbamforth]

Not really a new rotorcraft concept, but a few guys here are interested in that kind of thing.

See here.

http://www.rotaryforum.com/forum/showthread.php?t=6405

As a general point operating at low level with rotorblades close to the ground is normally regarded as one of the most dangerous parts of a flight.

For a similar cost you can probably build a gyrobee and fly somewhere other than just round the paddock.

[buckwill]

are your co-ax rotors counter rotating??how far apart would they be,, casn u talk the brits or the air force into sharing their ground following radar flight system

[SKYHAWG]

Chuck, the concept you are proposing sounds very interesting, but has already been proposed before by Dr. Paul Moller inventor of the moller ''skycar'' He proposed a similar idea with his VTOL ducted fan flying saucer.

All types of rotorcraft require that the pilot receives flight instruction. Even though the coaxial helicopters are somewhat easier to learn to fly it still requires that the person operating it has sufficient flight instruction.It's not like learning how to drive a go-cart.

Under 10-grand seriously? ready to fly. Some new gyroplane ''kits'' can't be purchased for that price.

I don't know the laws regarding hovercraft, but it will be interesting to hear what other forum members have to say regarding this.

-Harry

[RotoPlane]

I understand your enthusiasm 'cause I thought much the same as you. The problem with a rotor overhead, if I understand you correctly, is that these type of vehicles move in and around people and other various obstacles. If you plan on shrouding the rotor like an upside-down hovercraft, it may be safe enough.

The one I was thinking about looked like a round airfoil shaped hovercraft and the outboard 18" of the rotor blades forced upper grilled air down into the plenum. It had both a cyclic and collective stick for rotor control and could (should) stop forward speed the same way a helicopter can, with no need to swivel 180° first. I dreamed of jumping over fences, creeks, and yes even rivers .

[WHY]

Chuck

The weak link in a hovercraft, is that it is a hovercraft. Hovercraft are dependent on the terrain below the craft. Get over rough terrain and you got trouble BIG TIME. In there place, you can't beat 'em.

Tony

[brett s]

You'll find it impossible to mechanically limit it to 10' or less if it can gain any airspeed at all, short of tethering it anyways. Takes a lot more power to hover than you need in fwd flight...

I suspect the FAA would try to call it a helicopter if it looks & acts like one, the pilot just supposedly not going higher than 10' won't cut it - otherwise anybody could take an existing helicopter & do the same thing.

How fast are you thinking it'll go? Anything much above walking speed at low level is where it gets dangerous if the engine quits.

[Rotor Rooter]

Chuck,

At 10' above the ground it will probably be operating out of ground effect. Therefore to be a viable and safe craft it will probably end up as a rotorcraft.

With the rapid growth in quadrotors and electronic stabilization, what about a manned and skirted quadrotor hovercraft? Just an idea.


Dave

[Jens]

Helicopter
Hovercopter
Hovercraft

Yes Chuck, it is A New Rotorcraft Concept you are describing - so new that hardly any exist.
And with no proper and well defined word for them, they might never really come into existents.

So, what to name something in between a Hovercraft and a Helicopter, which is more helicopter than hovercraft?
You call them "rotor-bladed hovercrafts".
I name them Hovercopters.

See Hovercopter thread here:
http://www.rotaryforum.com/forum/showthread.php?t=23536

[Chuck Baltzer]

And another name might be “RIG”, because a hovercraft that flies with stubby wings is called a “WIG”, “Wing In Ground (effect)”, and this machine was supposed to levitate with rotor-blades and stay (basically) in ground effect, hence- “Rotor-blade In Ground (effect)” “RIG”.

But it’s mostly a moot point- you were right- (that is, everybody that posted above on the subject)- if you build a small, 2 seat helicopter and then tack the words “hovercraft” on the side, instead of, let’s say, the word- “Experimental”, the government is going to take one look at it and say, “It’s a helicopter- no matter what you have written on the side, or no matter how high you hover”.

What got me started on this idea was some of the bizarre things I have been seeing on the internet, mostly on Youtube, for example, have you checked out: Niestabilny helikopter (on youtube- search “Niestabilny helikopter” I tried to add the link here, but when I try to post it on the forum- it doesn’t appear) this guy looks like he could have enjoyed something safer than what he had strapped to his back, or another contraption called “the flying shopping cart” that actually does fly around for a little bit, see: Pionowzlot (on youtube- search “Pionowzlot” I tried to add the link here, but when I try to post it on the forum- it doesn’t appear)

Those guys, and hobbyists like them probably wish there were something like the low-cost “rotor-bladed hovercrafts” that have been discussed, but like all the people that posted have pointed out- the government will never buy into the idea.

However- since we’re on this subject of unusual rotary winged vehicles- please read my next post below- it concerns my other brainstorm idea for an alternative type of hovering vehicle- all I need to know is why this next idea wouldn’t work, (or WOULD it?) and then I’ll be able to go back to work without thinking about this all day.

[Chuck Baltzer]

Ok, so here’s my next brainstorm idea- this idea I think is really cool, much better than the last one.

We’re all familiar with the Moller flying saucer, or if anybody hasn’t seen it yet- there’s at least one Youtube video that shows it in action. Here’s what I was thinking: I believe it’s the shape and weight of that vehicle that keeps it from becoming more popular with the buying public.

It has 8 Wankel engines connected to ducted fans for lift. I’m not sure what the horse power is for each rotary engine- each website that talks about the saucer’s engines gives them a different HP.

But here’s what I was thinking: Lets say that the design of the craft is radically altered- so it looks like a jet-ski, that is a typical personal water craft. But it’s not a jet-ski, it just looks like one- it has an aluminum frame, fiberglass body, and a ducted fan, downward thrust, rotary engine on each of the four corners- a craft that looks like a jet-ski with four props underneath pushing down , lifting the craft up- a cross between a hovercraft and a jet-ski that can rise up to a height of, say, 10 feet!!

It could be, as mentioned in the posts above, electronically stabilized, and made to come into a stable hover at one foot AGL if the driver’s hands came off of the handlebars. The handle bar would serve as the “cyclic” to control the louvers under the ducts for directional control- just push the bars in the direction you want to go- and a motorcycle-type throttle grip on the handle bars would control altitude.

This machine would be smaller and lighter than the Moller craft- and would therefor need fewer and less powerful engines.

Now stop and think about this- how many guys and girls do you know who’d LOVE to hop on a “flying” jet-ski and go for a ride- ANYWHERE- water, land, grass, fields etc.??

The traditional defect in the idea has been that everyone wants to build a “flying car”, which needs much more power than this lighter craft, flying cars are inherently dangerous, and this jet-ski hovercraft doesn’t need to fly in the traditional sense- it just needs to get up to the hovercraft limit of 10 feet (or less).

The engines and ducted fans needed for this craft would be the exact same type of engines and ducted fans used in the Moller flying saucer- there’s even a company that sells these types of engines- they’re light-weight, cylindrical-shaped, and come in a variety of horse powers.

The ducted fans could be entirely under the frame, or partially protruding (half moon shape showing out the side of the bottom corner), or entirely external- like on the Moller Sky-Car.

There are many more details that could be discussed, but, is there any reason that this idea wouldn’t work? If it would work, what would the HP of the 4 engines need to be to lift a craft of this type?

[brett s]

Moller Skycar is one of the biggest & longest running scams in aviation history.

Look into how much (other peoples) money has been spent over the last 40 years without delivering a product, or how impossible some of the projected M400 specs are.

The reason it's not "more popular" is because it doesn't work!

[Rotor Rooter]

Your basic idea has validity.

Here are some sub-ideas that you might want to consider.

• Hoverbike ~ but with 4 rotors (quadrotor) for stability and safety etc.
• Electronic 3-axis stabilization. These boards can be purchased.
• Very high inertia rotors - to provide for a soft landing from a low flying elevation, should an engine (motor) quit. [Modified by edit.]
  
• If the craft has surplus power, it should be possible to make the craft 'jump' over obstacles (fences etc.).
• To add to Brett's comment ~ use larger propellers (small rotors) since they offer a lower disk loading and greater efficiency.
• Forget the louvers. The quad rotors will all the control that you need. [Added by edit.]
• Keep the craft simple but reliable.

IMHO the future for rotorcraft is;

• Miniature unmanned craft for in-flight functions.
• Small manned craft, which are simple and reliable, for recreational activities.
• Large craft; with and without pilots, for transportation functions.

Dave

[Chuck Baltzer]

Originally Posted by brett s

Moller Skycar is one of the biggest & longest running scams in aviation history.

Look into how much (other peoples) money has been spent over the last 40 years without delivering a product, or how impossible some of the projected M400 specs are.

The reason it's not "more popular" is because it doesn't work!

BUT the Moller flying saucer (and M400) did actually get off the ground- the flying saucer actually flew around for a bit, but mostly hovered, and the Sky Car lifted off and hovered for for a certain number of minutes (or seconds?) proving that the engines and fans did in fact work.

My idea would not bare any resemblance to Moller's machines- his crafts simply proved the usefulness of the engines and fans he used- these engines and fans are available (for the right price) through companies other than Moller.

If anybody hasn't seen the Moller flying saucer or Sky-Car in action, they can be readily viewed on Youtube (with a little searching and patience).

[Chuck Baltzer]

While we're on the subject, and despite what the final body style will look like, let's just say we're dealing with our basic frame with four engines with ducted fans- one on each corner of the craft. Can anybody calculate how much horse power would be needed to lift this craft off the ground (without a hovercraft skirt, of course), or even make a reasonable guess?

From all I've read, my best guess-timate would probably be approximately 50 HP per individual engine (200 HP collectively), with 18" to 24" fans- and I'm only talking about getting the craft up into ground effect- from 12 to 24 inches in this case.

I could be way off, or dead on target. This is really the gist of this kind of project- if anybody can actually come up with the figures for horse power and propeller size verses the weight to be lifted (for ducted, downward vectored fans), then they've achieved somewhat of a major goal in the building process. Because after that, it's only a matter of obtaining and assembling hardware.

Anyone have any ideas on what the proper values would be?