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March 13, 2012

New VTOL concept could result in helicopter/airplane hybrids

During the past several decades a number of different proposals for Vertical Take Off Landing (VTOL) craft have been considered. The most famous of these designs has been the controversial V22 Osprey, which has a maximum speed of 316 MPH and a 1,000 mile range. Although there have been plans to create civilian aircraft based on the V-22, a number of other VTOL approaches are being considered. In the 1960s the Fairey rotodyne concept was successfully tested but abandoned because of noise concerns. In more recent years Kareem Aircraft's JHL heavy-lift VTOL craft, as well as Oliver VTOL's hexplane six-engine concept have been examined. But another VTOL concept may be superior. Two aerospace engineers have come up with a VTOL approach that uses both a helicopter rotor and jet engines. In an interview with Sander Olson for Next Big Future, Eli Alexander, a 97 year old aircraft designer who once worked for Hughes aircraft and consulted with Howard Hughes, describes the merits of a hybrid rotor/Jet design. If Alexander is correct, VTOL passenger jets the size of A-330 aircraft could someday be ferrying passengers on both short and long-range flights.

Augusta Westland tiltrotor

Eli Alexander Interview

Question: How long have you been working in aviation?

Answer: I have been working in this field for 76 years. I recently turned 97 but am still active.



Oliver VTOL Hexplanes

A 12,500 pound class Hexplane can carry 1,000 pounds, 1,000 statute miles at 400 miles per hour. This meets the recent DARPA performance challenge to the VTOL industry. This same aircraft is predicted to achieve speeds of approximately 450 mph at 25,000 feet.



Gerbino Flight Systems FAQ has an image of the Fairey Rotodyne.

From the FAQ - This is such a great idea because no one has ever done it like this before". Sadly, there's a very good reason why no-one has done it like that before.

How to control the rotor blades in and out has always been the problem. It has to be positive all through the transition within 1/10’s of a degree for balance and control.




Question: How long have you been involved in VTOL research?

Answer: I have been researching various VTOL concepts for 57 years, since 1956.

Question: The Farley Rotodyne concept of the early 1960s, which could carry 40 passengers, was cancelled in 1962. Was the concept viable?

Answer: No, the concept was not practical. It was too noisy and was an auto gyro.

Question: The V22 Osprey is a controversial aircraft. What is your assessment of the V22? Could a civilian variant be successful?

Answer to both questions: The V-22 is very costly to maintain and to operate, and has poor emergency procedures.

Question: Other VTOL concepts are being explored, including the hexplane and Karem aircraft’s tiltrotor and Oliver VTOL’s hexplane. How does the Gerbino model compare?

Answer: Our proposal is more reasonable. It is much less costly and is the only system that has emergency recovery procedures in all 3 modes of flight: Helicopter, fixed wing and auto gyro.

Question: What are the maximum speed, altitude, and range of your VTOL craft.

Answer: Speed is only limited by the engine power and the parasite drag of the aircraft. Altitude is determined by flight mode(helicopter or fixed wing). The Range will be determined by fuel onboard. The aircraft has drop tanks and is refuelable in flight.

Question: Doesn’t the rotor add a significant amount of dead weight to the craft during the majority of its flight time?

Answer: No. The extra weight penalty is extremely reasonable for the benefits and in forward flight it carries it self.

Question: The model that you have developed is fairly small. Could this concept be scaled to a much larger plane, such as a jetliner?

Answer: Certainly yes. It is scalable up to and through the new A-330 jet airliner and larger.

Question: What would the airframe be made from? Aluminum, titanium, composites, or a combination of all three?

Answer: Any one of them or a combination of all three could be used for the airframe.

Question: Approximately how much would it cost to build a working prototype of this device? How much would a production model cost?

Answer: A search and rescue craft for troops might cost $5M. Building a production model should cost $3.2M. To complete our proof of concept would cost $1M.

Question: Have you been able to garner any funding to pursue this concept?

Answer: We have invested our own monies. We have entertained investors but they want to own the project and we are not going to go there.

Question: You plan on licensing this concept to aviation companies. Have any corporations shown interest in the project?

Answer: Yes, but unfortunately there has been no follow up from them.

Question: Assuming sufficient funding, how much progress could you make in the VTOL aircraft within the next decade?

Answer: Assuming adequate funding, we could make tremendous progress within the next decade.

Question: Could VTOL aircraft ever become commonplace?

Answer: Definitely yes. Our design is simpler and easier to service and maintain than competing concepts. it does not need an airport, and can land on a ship, airport, an unimproved field, or in any closed area.









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