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Xantus      Early 2000

Because of the enormous reaction to this incredible aircraft, we have been inundated with email asking for additional information.  There is no further information available beyond what is present on this website.  Please limit email inquiries to serious investors and journalist!

The World’s First Economical VTOL Airplane Designed to be Built for a Fly-Away Cost similar to a Conventional High Performance Four Passenger Kitplane.

The Xantus is a new four passenger tilt-prop aircraft which is able to take off and land vertically, like a conventional helicopter, yet is able to cruise at 290 mph!

This new aircraft is initially intended for Amateur & Kit Built Applications.

Performance         

Empty Weight                        1500 lbs

VTOL Gross Weight              2400 lbs

STOL Gross Weight              3000 lbs

Fuel Capacity                         80 gal

Range (50% power)               800 nm

Cruise Speed (75% power)   288 mph

Maximum Speed                      325 mph

Conventional Takeoff Roll       < 500 feet

STOL Takeoff Roll                    < 300 feet

VTOL Takeoff Roll                      0 feet

Rate of Climb                           > 4000 feet per minute

Service Ceiling                        > 25000 feet

Engines                                    4  each @ 125 hp

Propellers (production)             Constant Speed Electric

Noise level                               < 90 dBA @ 100 feet

First flight                                 July 11, 1999

  * All information is based on production configuration

Note:  Due to the dynamic nature of Xantus development, we have chosen to use this website as our official information source.  Using this medium, we can better inform the public of this exciting revolution in personal vertical flight.  More extensive information, including an information packet and video will be available at a later time.  Check this website for the latest information as it becomes available. 

If you are interested in Xantus investment opportunities or are an experienced kit aircraft builder in Southeast Michigan and would like more information, please contact us at info@vtol1.com.

VTOL1 FAQ

How much does it cost to operate the Xantus?

Many people think that with four engines the Xantus will be very expensive to operate, but that just isn’t so. Here’s how it breaks down:

At 250 mph, the fuel flow is about 20 gph, or about 12.5 miles per gallon (about the same as a Bonanza). While the Xantus can use either aviation gas or unleaded premium auto gas, we’ll assume you’re using auto gas. We further assume that the gas costs $1/gal. The Xantus’ 2-cycle engines use oil constantly as they run. This results in an additional $.20 per gallon; so, the total fuel cost is about $24 per hour, or about $.095 per mile. For comparison, a Bonanza costs about $.17 per mile for gas.

Even though your Xantus will be licensed in the Experimental category and you can do your own maintenance, we’ll allow $1000 per year for replacements and/or upgrades.

While most people will want to keep their Xantus at their homes for convenience and to avoid hanger costs, you will have to check local ordinances to be sure you can. Just contact your local police department and ask if there are any state or local ordinances preventing you from landing a helicopter in your yard.

For estimating purposes, we’ll assume you decide to purchase both hull and liability insurance, and that the pilot has at least 500 hours of multi-engine experience. You should be able to purchase such a policy for about $3000 per year.

You’ll want to set aside something for engine reserve, and this is where the Xantus shines. These two cycle engines are so simple that the local distributor says he will overhaul them for $500 each assuming no major damage has been done. While the engines will probably hold up for well beyond their factory warranted 1000 hours, we’ll assume that you are conservative and overhaul all four engines at the 1000 hour mark. The engine reserve works out to $2 per hour for your Xantus; that compares to about $10 per hour for a Bonanza and up to $50 per hour for a turbo-charged twin.

For our final assumption, we’ll assume that the average pilot flies his Xantus 75 hours per year.

Now let’s do the math:

Why don’t you use gearboxes to interconnect and synchronize the engines?

Aerospace gearboxes are relatively heavy and very expensive, and while most people think gearboxes are very reliable, when you make them light-weight, put hundreds (or thousands) of horsepower through them continuously, and install them in wings that flex and bend, they become a nightmare. The trick is to design a VTOL aircraft that doesn’t need gearboxes.

In the 1960’s when we were all driving cars equipped with carburetors and conventional ignition systems we put-up with hard starting, tune-ups twice a year, and engine overhauls every 70 to 80 thousand miles. If you didn’t perform this maintenance, your car would break-down.

Today our cars start in any weather, need a tune up every 100 thousand miles, and in most cases we junk the car before the engine wears out. The only significant difference is the engine accessories.

The electronics revolution that brought us precise and reliable control of our car engines also brought about a complete change in our attitudes about them. We now expect our engines to run forever and to last forever, and with few exceptions, they do.

But little if any of this has percolated down to the aircraft industry. Most of us still use carburetors and magnetos, because while electronics failures are very rare, they tend to be sudden and unpredictable.

The solution is simple and, surprisingly, not that expensive: dual redundancy. Every critical electronic engine control function must be dual-redundant with automatic conversion. If you add to that dual-redundant electrical power, dual redundant fuel systems, and computer monitoring and display of every aspect of engine operation and condition, you have a VTOL engine system that you can expect to run forever.

But what if something does go wrong! Each four cylinder engine is set-up as two, two cylinder engines on a common drive shaft. The two, two cylinder pairs do not even share the same crankcase. The worst remote failure would result in the loss one two cylinder pair. The Xantus can lose one two cylinder pair and continue to hover at 7000 feet MSL at full gross weight on a hot day.

That is Reliability, and that is why we don’t need or use gearboxes.

How does it work?

The Xantus uses multiple levels of redundancy to achieve previously unattainable reliability and safety. Each engine has dual ignition and dual fuel injection systems. Each engine is configured as two completely independent two cylinder engines. The aircraft has dual redundant fuel and electrical systems. Every system has an independent, automatic backup. Also every Xantus comes with an Engine Instrument, Cockpit Advisory System (EICAS) that continuously monitors and displays the status of every engine CHT, EGT, and speed, as well as, all the other aircraft systems. Only propellers and engine crankshafts are flight critical, as they are on every other aircraft flying.

How many engines are required to keep the Xantus flying?

Only one. With a normal thrust to weight ratio of 1.5 to 1, the Xantus would still have a climb rate greater than a Cessna 172 if only one engine were operating.

Is the Xantus a "fly by wire" design?

No. All the flight controls are simple and conventional. Ailerons, elevators, and the rudder are just like those on every other general aviation airplane. In hover mode, the throttles are mechanically coupled to the control stick, and pitch and roll are achieved by independently changing the thrust of each engine. The throttle is used to change the thrust of all the engines together, and the pilot flies the aircraft in a natural manner familiar to every pilot.

What happens if an engine loses power?

In cruise flight, the results are similar to any multi-engine airplane except that with its exceptional thrust to weight ratio the Xantus can still climb at over 3000 fpm. In hover flight, the loss of power results in a thrust imbalance that will cause a sudden change in pitch and roll similar to a strong wind-gust. The pilot will be looking outside, and he won’t know what caused the sudden change. He will just continue to fly the aircraft as normal. Repositioning the control stick will rebalance the thrust of the engines, restore the aircraft attitude, and pushing the throttle forward will correct for the combined thrust loss. The aircraft can lose any pair of cylinders and continue to hover at maximum gross weight at up to 7000 ft. at hot day conditions.

Is the Xantus unstable in a hover like a helicopter?

Technically, yes. "Time to double" is an engineering measure of any aircraft’s instability. The Beech Bonanza is known to be unstable in roll (spiral instability), since it takes 10 to 15 seconds for a 5 degree bank to double to 10 degrees (if left uncorrected). Most pilots don’t even notice this level of instability. Like the Bonanza, in a hover the Xantus has a "time to double" of 10 to15 seconds (in pitch and roll). While this is still unstable in engineering terms, it is many times more stable than a light helicopter, like the R-22, that has a "time to double" of 1 to 2 seconds. In conventional flight, the Xantus is about as stable as a Cessna 182.

What engines does the Xantus use?

The Xantus uses four Hirth F-30, 2-cycle, 4-cylinder, aircraft engines. While some people think 2-cycle engines are not reliable, we researched 2-cycle engine failures and found that the vast majority of problems are not related to the mechanical design of the 2-cycle engine but occur due to poor engine accessory design and/or the maintenance of the engine (usually on an ultra-light). We chose Hirth engines because of their robust design, and then we modified them to make every accessory system dual redundant.

What pilot license and ratings are required to fly the Xantus?

In July of 1997, the F.A.A. changed the F.A.R.’s in preparation for the soon to be certified Bell 609 tilt-rotor aircraft. They added a new category of aircraft called "Powered-Lift" to the previous categories (airplane, rotorcraft, sailplane, and balloon). The required license category and class to pilot the Xantus will most likely be "Powered-Lift, Multi-Engine Land." Initially, similar to when helicopters first entered the market-place, the company selling the aircraft will need to provide the training required for the prospective pilot to become licensed. This approach is clearly in the best interest of the pilot, the company, and the flying public.

Since the Bell 609 is being marketed at $10,000,000, why do you think the Xantus can be built for about the cost of a conventional high performance aircraft?

Although production prices for the Xantus have not been set, we expect fly-away cost to be comparable to other conventional high performance aircraft.  This "fly-away" cost includes engines, full IFR avionics, all components, all materials, and all the tooling. Clearly, we have reasons to be confident in the above figure as our prototype aircraft has substantiated our cost targets. Subsequent aircraft will cost even less, keeping the Xantus as an option to anyone who can afford an experimental aircraft of comparable cruise speed and payload.

This web was last updated April 06, 1999

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