Paul Bevilaqua
Encyclopedia
Paul Bevilaqua is an aeronautics engineer at Lockheed Martin
in California. In 1990, he invented the lift fan
for the Joint Strike Fighter F-35B
along with fellow Skunk Works
engineer Paul Shumpert.
in Aeronautics
and Astronautics (subject: Turbulent
wakes) at Purdue University
in 1973.
This seems to be concurrent with activities as an Air Force Lieutenant at Wright-Patterson Air Force Base
(WP-AFB), where he began professional work in 1971.
At some point he became Deputy Director of the Energy Conversion Lab at WP-AFB
, managed by jet inventor Hans von Ohain
.
In 1975 Paul left the Air Force
to be a Manager of Advanced Programs at Rockwell International
's Navy Aircraft Plant.
Ten years later, in 1985, he was appointed Chief Aeronautical Scientist at Lockheed
, trying to come up with a new line of business.
Hans von Ohain
inspired Bevilaqua to think like an engineer rather than a mathematician - "in school I learned how to move the pieces, and Hans taught me how to play chess", although he said that about Purdue as well.
Ohain also showed Paul "what those TS-diagrams actually mean".
While at WP, Ohain, Bevilaqua and others investigated (see #List of Papers) and patented various flow related concepts, some of them flow multipliers related to vertical take-off and landing
.
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(For the physical system, see Rolls-Royce LiftSystem
)
In the 1980s, the United States Marine Corps
wanted a Vertical/Short Takeoff and Landing (V/STOVL) aircraft
with more speed
and payload than the Harrier
/AV-8B
.
Bevilaqua was working for Lockheed Skunk Works in 1986, when DARPA and the similar British agency launched a program called ASTOVL and issued a 9-month contract to develop concepts for a stealthy
supersonic
STOVL
plane, in accordance with USMC wishes, but without the usual strict technical requirements.
The challenge in combining supersonic flight and STOVL is that an engine powerful enough to lift
an aircraft would be too wide to be supersonic, as shown by the Harrier
. A smaller engine with higher air flow was needed, but seemed impossible.
Inspired by the General Electric CJ805
-23 aft-turbofan and the Rolls-Royce
tandem-fan, an appropriate system seemed to be a dual thrust system with a lift vector at the front and a swivel nozzle at the back for the jet engine, counterbalancing each other.
In order to leave no stone unturned, all kinds of options were investigated, some even bordering on the ludicrous (using a cannon for lift, transferring power with a laser beam) - Skunk Works employees are no strangers to cartoon antics.
With one month left and no results, he took yet another look at the situation. Three elements were clear :
but that was tried by many and found insufficient - something more was needed.
Exploiting bypass air is the usual way of increasing thrust, but when air flow drops so does pressure, which increases engine speed at the risk of failure. This apparent flaw suddenly turned to a benefit when it dawned upon him that the extra engine power could be put to good use by turning a lift fan. "It took eight months of brainstorming to program the computer in my head, and ten seconds to come up with the idea."
In other words; transforming some of the jet blast to vertical air flow by extracting energy from the hot jet blast with a turbine that turns a shaft driving a fan pointing down, thereby increasing impulse and thus lift, without increasing drag
.
The system works similarly to a turbofan
, with an extra bypass fan moved and tilted 90 degrees to move cool unburned air vertically instead of horisontally, or a turbine helicopter whose rotor is shrunk and encased. This effect is similar to the previous flow multiplier concepts investigated by Bevilaqua (see #List of Papers) and others (although methods are different), achieving a lift/thrust-ratio of 1.5:1 where previous successful aircraft were limited to 1:1 at best.
Paul is not a propulsion
engineer, and got help from various Lockheed experts in propulsion, materials and other specialised fields in order to verify the theories of the concept, which was then patented.
Both DARPA and the Marine Corps liked the concept, and from there it developed through various defense programs such as CALF and JAST into the Joint Strike Fighter Program and through to the X-35B and F-35B. Bevilaqua was a key figure in persuading the Air Force in 1992 that the concept aircraft could be useful as a conventional aircraft
without the LiftFan. When the US Navy also came onboard, the road was paved for the JSF concept of similar aircraft with different applications, in accordance with JAST Concept Exploration findings.
The practical development of the F135 engine
and system was performed by Pratt & Whitney
, Rolls-Royce and others.
One of the key factors in handing the $200B JSF contract to LM is said to be when the X-35B took off from 150feet of runway, went supersonic, and landed vertically in one flight on July 20, 2001 - a performance that only the X-35B has done, and only because of the LiftFan concept.
The JSF team was awarded the Collier Trophy
2001 for the working system.
Lockheed Martin
Lockheed Martin is an American global aerospace, defense, security, and advanced technology company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It is headquartered in Bethesda, Maryland, in the Washington Metropolitan Area....
in California. In 1990, he invented the lift fan
Rolls-Royce LiftSystem
The Rolls-Royce LiftSystem is an innovative propulsion system designed for use in the STOVL variant of the F-35 Lightning II developed during the Joint Strike Fighter Program...
for the Joint Strike Fighter F-35B
F-35 Lightning II
The Lockheed Martin F-35 Lightning II is a family of single-seat, single-engine, fifth generation multirole fighters under development to perform ground attack, reconnaissance, and air defense missions with stealth capability...
along with fellow Skunk Works
Skunk works
Skunk Works is an official alias for Lockheed Martin’s Advanced Development Programs , formerly called Lockheed Advanced Development Projects. Skunk Works is responsible for a number of famous aircraft designs, including the U-2, the SR-71 Blackbird, the F-117 Nighthawk, and the F-22 Raptor...
engineer Paul Shumpert.
Life and career
Paul got a DoctorateDoctorate
A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder to teach in a specific field, A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder...
in Aeronautics
Aeronautics
Aeronautics is the science involved with the study, design, and manufacturing of airflight-capable machines, or the techniques of operating aircraft and rocketry within the atmosphere...
and Astronautics (subject: Turbulent
Turbulence
In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic and stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time...
wakes) at Purdue University
Purdue University
Purdue University, located in West Lafayette, Indiana, U.S., is the flagship university of the six-campus Purdue University system. Purdue was founded on May 6, 1869, as a land-grant university when the Indiana General Assembly, taking advantage of the Morrill Act, accepted a donation of land and...
in 1973.
This seems to be concurrent with activities as an Air Force Lieutenant at Wright-Patterson Air Force Base
Wright-Patterson Air Force Base
Wright-Patterson Air Force Base is a United States Air Force base in Greene and Montgomery counties in the state of Ohio. It includes both Wright and Patterson Fields, which were originally Wilbur Wright Field and Fairfield Aviation General Supply Depot. Patterson Field is located approximately...
(WP-AFB), where he began professional work in 1971.
At some point he became Deputy Director of the Energy Conversion Lab at WP-AFB
Wright-Patterson Air Force Base
Wright-Patterson Air Force Base is a United States Air Force base in Greene and Montgomery counties in the state of Ohio. It includes both Wright and Patterson Fields, which were originally Wilbur Wright Field and Fairfield Aviation General Supply Depot. Patterson Field is located approximately...
, managed by jet inventor Hans von Ohain
Hans von Ohain
Hans Joachim Pabst von Ohain was a German engineer, one of the inventors of jet propulsion.Frank Whittle, who patented in 1930 in the United Kingdom, and Hans von Ohain, who patented in 1936 in Germany, developed the concept independently during the late 1930s...
.
In 1975 Paul left the Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
to be a Manager of Advanced Programs at Rockwell International
Rockwell International
Rockwell International was a major American manufacturing conglomerate in the latter half of the 20th century, involved in aircraft, the space industry, both defense-oriented and commercial electronics, automotive and truck components, printing presses, valves and meters, and industrial automation....
's Navy Aircraft Plant.
Ten years later, in 1985, he was appointed Chief Aeronautical Scientist at Lockheed
Lockheed Corporation
The Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...
, trying to come up with a new line of business.
Hans von Ohain
Hans von Ohain
Hans Joachim Pabst von Ohain was a German engineer, one of the inventors of jet propulsion.Frank Whittle, who patented in 1930 in the United Kingdom, and Hans von Ohain, who patented in 1936 in Germany, developed the concept independently during the late 1930s...
inspired Bevilaqua to think like an engineer rather than a mathematician - "in school I learned how to move the pieces, and Hans taught me how to play chess", although he said that about Purdue as well.
Ohain also showed Paul "what those TS-diagrams actually mean".
While at WP, Ohain, Bevilaqua and others investigated (see #List of Papers) and patented various flow related concepts, some of them flow multipliers related to vertical take-off and landing
VTOL
A vertical take-off and landing aircraft is one that can hover, take off and land vertically. This classification includes fixed-wing aircraft as well as helicopters and other aircraft with powered rotors, such as cyclogyros/cyclocopters and tiltrotors...
.
Invention of LiftFan
(For the physical system, see Rolls-Royce LiftSystem
Rolls-Royce LiftSystem
The Rolls-Royce LiftSystem is an innovative propulsion system designed for use in the STOVL variant of the F-35 Lightning II developed during the Joint Strike Fighter Program...
)
In the 1980s, the United States Marine Corps
United States Marine Corps
The United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...
wanted a Vertical/Short Takeoff and Landing (V/STOVL) aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
with more speed
Airspeed
Airspeed is the speed of an aircraft relative to the air. Among the common conventions for qualifying airspeed are: indicated airspeed , calibrated airspeed , true airspeed , equivalent airspeed and density airspeed....
and payload than the Harrier
Harrier Jump Jet
The Harrier, informally referred to as the Jump Jet, is a family of British-designed military jet aircraft capable of vertical/short takeoff and landing operations...
/AV-8B
AV-8B Harrier II
The McDonnell Douglas AV-8B Harrier II is a second-generation vertical/short takeoff and landing ground-attack aircraft. An Anglo-American development of the British Hawker Siddeley Harrier, the Harrier II is the final member of the Harrier family that started with the Hawker Siddeley P.1127 in...
.
Bevilaqua was working for Lockheed Skunk Works in 1986, when DARPA and the similar British agency launched a program called ASTOVL and issued a 9-month contract to develop concepts for a stealthy
Stealth aircraft
Stealth aircraft are aircraft that use stealth technology to avoid detection by employing a combination of features to interfere with radar as well as reduce visibility in the infrared, visual, audio, and radio frequency spectrum. Development of stealth technology likely began in Germany during...
supersonic
Supersonic aircraft
A supersonic aircraft is designed to exceed the speed of sound in at least some of its normal flight configurations.-Overview:The great majority of supersonic aircraft today are military or experimental aircraft...
STOVL
STOVL
STOVL is an acronym for short take off and vertical landing.This is the ability of some aircraft to take off from a short runway or take off vertically if it does not have a very heavy payload and land vertically...
plane, in accordance with USMC wishes, but without the usual strict technical requirements.
The challenge in combining supersonic flight and STOVL is that an engine powerful enough to lift
Lift (force)
A fluid flowing past the surface of a body exerts a surface force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the surface force parallel to the flow direction...
an aircraft would be too wide to be supersonic, as shown by the Harrier
Harrier Jump Jet
The Harrier, informally referred to as the Jump Jet, is a family of British-designed military jet aircraft capable of vertical/short takeoff and landing operations...
. A smaller engine with higher air flow was needed, but seemed impossible.
Inspired by the General Electric CJ805
General Electric CJ805
|-See also:-External links:* * *...
-23 aft-turbofan and the Rolls-Royce
Rolls-Royce plc
Rolls-Royce Group plc is a global power systems company headquartered in the City of Westminster, London, United Kingdom. It is the world’s second-largest maker of aircraft engines , and also has major businesses in the marine propulsion and energy sectors. Through its defence-related activities...
tandem-fan, an appropriate system seemed to be a dual thrust system with a lift vector at the front and a swivel nozzle at the back for the jet engine, counterbalancing each other.
In order to leave no stone unturned, all kinds of options were investigated, some even bordering on the ludicrous (using a cannon for lift, transferring power with a laser beam) - Skunk Works employees are no strangers to cartoon antics.
With one month left and no results, he took yet another look at the situation. Three elements were clear :
- a turbine is the best way of extracting power from a jet
- a shaft is the best way of transferring that power forward
- a fan is the best way of converting power to thrust or lift
but that was tried by many and found insufficient - something more was needed.
Exploiting bypass air is the usual way of increasing thrust, but when air flow drops so does pressure, which increases engine speed at the risk of failure. This apparent flaw suddenly turned to a benefit when it dawned upon him that the extra engine power could be put to good use by turning a lift fan. "It took eight months of brainstorming to program the computer in my head, and ten seconds to come up with the idea."
In other words; transforming some of the jet blast to vertical air flow by extracting energy from the hot jet blast with a turbine that turns a shaft driving a fan pointing down, thereby increasing impulse and thus lift, without increasing drag
Drag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...
.
The system works similarly to a turbofan
Turbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
, with an extra bypass fan moved and tilted 90 degrees to move cool unburned air vertically instead of horisontally, or a turbine helicopter whose rotor is shrunk and encased. This effect is similar to the previous flow multiplier concepts investigated by Bevilaqua (see #List of Papers) and others (although methods are different), achieving a lift/thrust-ratio of 1.5:1 where previous successful aircraft were limited to 1:1 at best.
Paul is not a propulsion
Air propulsion
Air propulsion is the generation of thrust during flight by an aircraft or a creature such as a bird, bat or insect.-Aircraft:An aircraft propulsion system must serve two purposes. First, the thrust from the propulsion system must balance the drag of the airplane when the airplane is cruising...
engineer, and got help from various Lockheed experts in propulsion, materials and other specialised fields in order to verify the theories of the concept, which was then patented.
Both DARPA and the Marine Corps liked the concept, and from there it developed through various defense programs such as CALF and JAST into the Joint Strike Fighter Program and through to the X-35B and F-35B. Bevilaqua was a key figure in persuading the Air Force in 1992 that the concept aircraft could be useful as a conventional aircraft
CTOL
CTOL is an acronym for conventional take-off and landing, and is the process whereby conventional aircraft take off and land, involving the use of runways. The aircraft will taxi along the runway until its rotation speed is reached, then climb into the air...
without the LiftFan. When the US Navy also came onboard, the road was paved for the JSF concept of similar aircraft with different applications, in accordance with JAST Concept Exploration findings.
The practical development of the F135 engine
Pratt & Whitney F135
The Pratt & Whitney F135 is an afterburning turbofan developed for the F-35 Lightning II single-engine strike fighter. The F135 family has several distinct variants, including a conventional, forward thrust variant and a multi-cycle STOVL variant that includes a forward lift fan...
and system was performed by Pratt & Whitney
Pratt & Whitney
Pratt & Whitney is a U.S.-based aerospace manufacturer with global service operations. It is a subsidiary of United Technologies Corporation . Pratt & Whitney's aircraft engines are widely used in both civil aviation and military aviation. Its headquarters are in East Hartford, Connecticut, USA...
, Rolls-Royce and others.
One of the key factors in handing the $200B JSF contract to LM is said to be when the X-35B took off from 150feet of runway, went supersonic, and landed vertically in one flight on July 20, 2001 - a performance that only the X-35B has done, and only because of the LiftFan concept.
The JSF team was awarded the Collier Trophy
Collier Trophy
The Collier Trophy is an annual aviation award administered by the U.S. National Aeronautics Association , presented to those who have made "the greatest achievement in aeronautics or astronautics in America, with respect to improving the performance, efficiency, and safety of air or space...
2001 for the working system.
List of Papers
-
- Paul M. Bevilaqua "Evaluation of Hypermixing for Thrust Augmenting Ejectors," Journal of Aircraft, Vol. 11, No. 6, June1974, pp. 348-354
- Paul M. Bevilaqua, "Analytic Description of Hypermixing and Test of an Improved Nozzle," Journal of Aircraft, Vol. 13, No. 1, January 1976, pp. 43-48
- Paul M. Bevilaqua, "Lifting Surface Theory for Thrust-Augmenting Ejectors," AIAA Journal, Vol. 16, No. 5, May 1978,pp. 475-581).
- Paul M. Bevilaqua and Paul S. Lykoudis "Turbulence memory in self-preserving wakes", Journal of Fluid Mechanics, Volume 89, Issue 03, December 1978, pp 589-606
- Paul M. Bevilaqua, Howard L. Toms Jr "A Comparison Test of the Hypermixing Nozzle."
- Paul M. Bevilaqua, John D. Lee, "Development of a Nozzle to Improve the Turning of Supersonic Coanda Jets" (1980)
- Paul M. Bevilaqua One-page Preview of "Joint Strike Fighter Dual-Cycle Propulsion System", Journal of Propulsion and Power, 2005, vol. 21, no5, pp. 778-783
External links
- Paul Bevilaqua : The shaft driven Lift Fan propulsion system for the Joint Strike Fighter Presented May 1, 1997. DTIC.MIL Word document, 5.5 MB
- F-35B on Global Security