The Martin-Baker MB designs

One of the most obscure piston powered aircraft projects ever conceived by a British corporation has to be the Martin-Baker MB series. The small English company, founded by James Martin and Val Baker in the early 1930s, was at the outside looking in terms of the British Royal Air Force’s design and development programs. But that changed in the summer of 1938 (August 3rd) when the company’s MB-2 single seated fighter, powered by a Napier Dagger engine, took to the air on its maiden flight. The aircraft flew flawlessly prompting the RAF to take a hard look at the, by that time, unknown corporation. Martin-Baker followed the success of the MB-2 with the MB-3. The new air platform was design around a May 1939 Ministry of Defense (MoD) specification, F-18.39, which called for an aircraft that can ascertain speeds above 400 mph within a heavily armed airframe. The new 3 version would have been able to achieve the stated speed at an operational ceiling of 15,000 feet. It was designed with a powerful six 20mm cannons fitted along its wing structures. Only one MB-3 sample, unit R2492, flew. It did so on August 3rd 1942. Unfortunately the unit was lost a month later when during a routine testing exercise; the aircraft staled in mid air prompting the sample to plumb to the ground. The crash, not only put the entire MB-3 program in jeopardy, but the death of the test pilot, company founder Baker; was a serve blow that would have dire consequence for the small company in the years ahead.

Constant development and production delays assured that the MB-3 would never achieve full production status. In the sprig of 1943, the MoD canceled its pre-production order for the 3 version. With the end of the company’s biggest contract up to that date, James Martin was finally free of government constraints. Free to pursue his life log dream. Free to design the company’s greatest air structure, the MB-5. The version 5 of the basic MB concept was basically a redesigned MB-4, an air platform that was never developed past mockup status, with a more powerful engine base and a streamline fuselage. The new power plant planned for the 5 version was the Rolls-Royce Griffon engine. The engine, coupled with a new teardrop canopy design and rear fuselage radiator gave the 5 a distinct flying capability.


The MB-5 in flight. (photo, via author)

Although different in many aspects from the 3 unit, the 5 was also loosely based on the same 18.39 specification. Martin’s new airplane made its maiden flight on the morning of May 23rd 1944. It only took one flight for Martin and the rest of his dedicated staff to know they had something special in the aircraft. With a top speed profile of 460 mph, the MB-5 was able to outrun the best of the Luftwaffe’s piston engine fighters. It flight operational ceiling was 20,000 feet which again, was better than any German piston aircraft of the times. The 5 unit was an overwhelming success that an Aircraft and Armament Experimental Establishment’s Boscombe Down report called the basic MB-5 design “an excellent and infinitely better, from the engineering and maintenance point of view, than any other similar type of aircraft”. The plane was also a big success with all the pilots who flew it. Its streamline airframe made it easy to maneuver it and its reinforced wing structure gave it the stability to become one of the world’s best gun platforms. Despite the high acclimates the aircraft ran into the same problem as the 3 version, delays. Add to this the fact that World War II has just ended, and the “writing was on the wall” when it came to the future of the whole 5 program. In the fall of 1945, the company finally pulled the plug on its most successful aircraft design.

Martin will go on with the design and development two jet powered aircraft, but by the late 1940s the company shifted its overall philosophy towards the production of ejection seats and area that made this little British company a household name.

– Raul Colon

More information:
The Royal Air Force and Aircraft Design 1923 to 1939, Colin Sinnott, Frank Cass 2001
Bristol Aircraft since 1910, C.H. Barnes, Putman Books 1964
Planemakers II, David Mondey, Jane’s Defense, 1982

The Birth of the Seaplane!

The possibility of combining the ability to fly and the capacity of a marine vessel had been around even before the Wright Brothers flew their Flyer aircraft at Kitty Hawk, N.C. Serious experimentation on this concept began around 1897, but it was not until 1898 that the first attempt to fly a boat was made. Wilhelm Kress, an Austrian, began construction in 1898 on what would eventually be considered to be the first flying boat craft. It was a simple design. A tandem tri-plane frame fitted with two massive floats. Its power plant was a single Daimler 30hp engine, driving two broad propellers. The craft was first tested in October 1901 on a reservoir near Tullnerbach, Austria; it did not make it to the air. Problems with the floats and the aerodynamics of the fuselage doomed the aircraft. Undaunted, Kress pressed on with his ideas, and in 1903, was ready to make another attempt, but by this time the lack of interest on the project and his financial situation forced him to abandon the idea.

Experimentation with flying boats gained a renew interest with the news of the first ever powered controlled flight by the Wright Brothers in Kitty Hawk, NC. On the other side of the Atlantic, the Vosin Brothers, Charles and Gabriel; after receiving the news; promptly commenced work on their own flying boat design. Their hard work finally payoff when on June 6, 1905; Gabriel became the first man to take-off and land a plane on a body of water. Although the aircraft was used as a glider, which required an external power source to propel it into the air, the craft did prove the feasibility of the concept. The next aircraft design by the Vosin Brothers was destined to be a groundbreaker. Named the Bleriot III after the individual who requested the craft’s design and production; this new concept was made out of two wing structures in an ellipse form placed on tandems. The complete airframe floated on water by function of skids surrounded by sealed tubes. On a clear morning in May 1906, the Bleriot III was ready for the first of a series of tests intended to prove the aircraft’s airworthiness. In each test, the aircraft performed badly, leading the Brothers to suspend further collaboration with Bleriot on this particular project. Bleriot, unmoved by the Brother’s decision, tried himself to build a workable seaplane. In late 1906 he was ready for another set of trials, and again, the results were less than promising.

Fabre-Voisin Connection (photo, via author)
(photo, via author)

In the other side of the Atlantic, the United States military was quickly to recognize the potential of a sea-based plane. During the month of November 1908, an American aviation pioneer by the name of Glenn H. Curtiss performed an airframe modification to his already successful airplane, the June Bug. He removed the wheel undercarriage and replaced with a tandem of wooden floats covered by canvas. The new plane, named Loon, was first tested in late November 1908. Initial test results were somewhat promising. The Loon was able to lift itself from the water but with a relatively slow speed of 25mph; the Loon was not able to accelerate enough to gain air stability. The hydrodynamic drag caused by the massive floats was too much for the engine to propel the aircraft above that speed. Nevertheless, encourage by the test results on the Loon, Curtiss expanded his research. He followed the Loon with the modification of the Curtiss Model D for water duties. In this configuration, the Model D was fitted with a single canoe decked over with canvas. This configuration presented Curtiss with the same problems as before: hydrodynamic drag. But as with the Loon, the results were promising enough to encourage Curtiss to invest more resources on the project.

What history had in store next for Curtiss was truly groundbreaking. In early 1910, the U.S. Navy, after being refused by the Wright Brothers, asked the newly formed Curtiss Company to build an aircraft capable of taking-off from a platform installed on a warship. On November 14th, 1910, Eugene Ely, a Curtiss Company test pilot; successfully took-off from a provisional platform installed on the USS Birmingham near Hampton Roads, Virginia. A series of take-off flights followed, culminated with a successful landing of a Curtiss built plane on a provisional platform installed on the USS Pennsylvania in January 1911. However impressive these tests had been, the Navy’s top brass was not overly impressed. They focussed their attention on the development of an aircraft that could be launched and recovered by a battleship in times of conflict.

For the next phase of story of the development of the seaplane as a realistic alternative, one needs to look at a young French engineer. Henri Fabre, was born in Marseille in 1882 and since his early teen years he devoted his time in the study of aerodynamic forces. He experimented with kites and aircraft models to look at how aerodynamic characteristics of airframes and wings are affected by wind flow. He also studied the effects of hydrodynamic forces on a structure. Thus giving him an inside look at the forces that affect air travel. His first attempt at building a seaplane was a simple design. A conventional monoplane was modified to carry two floats mounted under the wing structure in a catamaran-type configuration. A small float was added to the tail section of the fuselage. The aircraft was powered by three Anzani engines capable of generating a 12hp each. They drove a single tractor propeller. The first series of test occurred in July 1908 and achieve little, if any, positive results. Reasons for the failure were never properly explained, but most aviation historians place the blame on the weight of the floats.

For his next design, Fabre chose a canard layout. On this configuration, the main wing structure was placed at the rear of the fuselage, with two small canard wings near the front. The idea behind the concept is simple. The canards, Fabre thought, would give the aircraft a long sought longitudinal stability. His first test of this new concept was performed on Christmas eve, 1909. The aircraft, powered by a single Anzani engine, took-off for a brief time, but ultimate fell hard to the water due to its underpowered characteristics. The relative short flight did show that the canard configuration could provide air control to the aircraft once airborne. Realizing that the aerodynamics was sound, Fabre promptly went out to find a more powerful engine to propel his new design. After searching hard for a power plant, a friend recommended to Fabre the Gnome’s Omega 7 cylinder rotary engine. The Omega was capable of generating 50 hp and its weight was a respectable 165 lb. With the engine now in hand, Fabre began the development of a new seaplane. As was in the case before, the new plane was centered on the canard wing configuration. What varied from previous designs was the massive wing area, now composing 258 sq ft. The Omega engine was installed at the end of the aft in the main frame. It was located in this area because Fabre calculated that a pusher-type system would better achieve the necessary lift-power ratio needed to propel the aircraft into a stable and controlled flight.

Testing on this new concept commenced in early March 1910. Immediately, taxing testing showed the aircraft’s sound aerodynamic characteristics. On the morning of March 11th, 1910 the Hydravion, the new name for the aircraft, was ready to take to the air for the first time. It was towed to the middle of the Etang de Berre. With nothing more that calm water surrounding the test site, the Omega engine was brought to life. Immediately, the aircraft responded to the Omega and the Hydravion achieved substantial speed in the water. After more taxi testing, the Hydroavion took to the air on that same day. In series of relative short flights, the Hydroavion once again demonstrated its ability to achieve flight status. Fabre continued his experiments into the spring of 1910. All successful flights, but on May 18th, 1910, with Fabre himself at the controls, the Hydroavion lost control and fell into the water from an altitude of approximately 130 ft. The crash did little to alter the course of the programme, the Hydroavion was recovered and repaired, but it did affect Fabre deeply, it is said that he never flew another aircraft after the incident.

(photo, via author)
(photo, via author)

Back in America, Glenn Curtiss was observing with interest the progress made by Fabre. He even took time to visit Fabre in late 1910. By this time, Curtiss had moved his winter flying operations to North Island in San Diego, CA. There, the weather was more conduits for sea-flight experimentation. After many months of research, Curtiss, now with the assistance of Lieutenant Ellyson, a brilliant U.S. Navy engineer that specialized in physics and mechanics; determined that the main obstacle to achieving flight status on a seaplane was the shape of the floats. They researched many forms of floats, eventually settling on a configuration first suggested by Fabre: the use of a flat bottom with a positive trim angle. On January 26th, 1911, after years of extensive research and development, Curtiss saw his dream come true when his new seaplane design, a bigger canoe configuration airframe fitted with the new floats; took to the air. The test result was more than promising; they inspired Curtiss to redouble his efforts. They did extensive modifications on the canoe frame as well as in the float configuration to make them flight operational.

Curtiss, now embolden by the test results, decided to call his old friend, Captain Charles F. Pond of the USS Pennsylvania. The same ship platform that Curtiss used for his ground breaking experiments; and asked him if he would mind that Curtiss made a ship call on the Pennsylvania, now anchored off San Diego Bay. Pond, who was at the time one of the few true advocates of naval aviation, was ecstatic about the possibility and gave Curtiss the go ahead order. On February 1911, Curtiss took-off from his base at North Island and proceeded to land at the side of the Pennsylvania. After arriving, the ship used its boat crane to lift up the aircraft to the deck, the same concept was used to put the plane back in the water. This amazing exercise performed by Curtiss was the first step in the operational development of the seaplane by the U.S. Navy. After the demonstration, Curtiss went on to develop several series of flying boats in 1912, some of them served in the Great War two years later. In France, Fabre recognized Curtiss’s achievements and promptly proclaimed him as the father of the operational seaplane. Fabre, sensing that there was not much new ground to break at that time, decided to abandon major experimentation with seaplanes. That did not mean that Fabre stopped completely his association with flying boats. He supplied floats pieces to many countries during the years up to the Great War, and during the conflict, he was placed in charge of the vaunted Saint Raphael Naval Aviation Depot.

The colorful story of the birth of the seaplane is actually the story of two dedicated and visionary men, Glenn Curtiss and Henri Fabre. The seaplane was born out of their collective dedication and vision. Their need to prove a new and untested concept improved our understanding of how aerodynamic forces affect a sea-based flying platform. We are indeed grateful for their compliments and contributions to the development of the airplane in an era dominated by skeptics and doubters. They truly gave birth to the seaplane.

– Raul Colon

 

More information:
The Pioneers: Henri Fabre (1882-1984)
Wikipedia: Glenn Curtiss
Glenn Curtiss, Father of Naval Aviation

Willard Custer Ideas, Ready for the Aviation World?

Engineers at the Georgia Institute of Technology Research Institute in Atlanta, U.S.; are quietly researching the possibility of applying a Channel Wing Configuration technology to the designs of future aircrafts platforms. The Channel Wing Configuration, when implemented on the wing design, would give the aircraft the ability to generate a high volume of lift, which could open the path to many design possibilities. The idea of configurating the wing design to be able to generate more lift has been around since the birth of aviation early in the 1900s. Preliminary studies by aviation engineers on the subject in the mid-to-late 1910s resulted in experimentation with various form of wing configurations and settings. Eventually, advances on airframe deign and a premium on engine performance took center stage, thus neglecting the concept of wing modification to achieve greater lift. For years, research into a greater lift-generating wing design was shaped by traditionalist aviation engineers and designers. Thus, radical new ideas were never fully pursued, that was until a brilliant Maryland inventor came forward with a new concept in 1935.

Willard Custer was one of the first true champions of the lift principal called aero physics. He stated that the amount of lift generated by any aircraft is determined by the speed on which the air flows over the wing, not solely on the speed of the wing moving thru the air as articulated by many. If a wing configuration were to be designed with deep channels, dropping like a couple of “smiles” under the propellers; then the aircraft would generate more lift with it than a conventional wing configuration. For Custer, the idea was simple enough. An aircraft can generate lift with zero forward speed utilizing the engines to provide the necessary airflow to sustain the plane in the air, thus achieving an impressive amount of Short Take-Off and Landing (STOL) capability. Additionally, with the channel wing shape, the engine thrust is propelled downward, providing the aircraft with the ability to perform short take-offs, and, as an added bonus; maintaining air control at relative slow speeds. The idea that an aircraft can achieve virtually vertical take-off and landing capabilities by re-designing its wing configuration a was radical concept in the late 1930s.

Custer CCW-1 (photo, via author)
Custer CCW-1 (photo, via author)

The aviation community did not think much of Cluster’s Channel Wing Concept. That’s the risk someone takes when propelling radical new ideas. Nevertheless, Custer marched on. In the summer of 1943, his first aircraft design with channel wings was demonstrated to the United States Army Air Forces in Maryland. Immediately, the CCW-1, as the plane was designated, was a media darling. Stories of this strange-looking aircraft, nearly hovering over the ground, fascinated many in the country. Unfortunately, the US Army was not one of them. They branded the CCW-1 impractical because of the extreme nose-up attitude requirement for landing. There were also issues about the survival of the CCW-1 in combat. Test flights showed that if one of the engines were to be lost, the pilot could not maintain effective control over the aircraft.

Despite the setback, Custer persevered, and in the fall of 1959; he presented his new aircraft, the CCW-5 to the Marine Corps. Again he was turned down. Mainly, for the reasons stated in 1943; the concept seemed to hit the wall. No major research was invested on the channel wing concept until 1995, when the idea was resurrected by Dennis Bushnell, Chief Researcher at NASA’s Langley Research Center in Virginia. For years Bushnell mulled over how to fit an aircraft in tight locations off the ground. He researched the accepted principals of direct thrust and rotary wings, but they were not able to produce the desired results, as recent experimentation had shown. But Bushnell had an ace. For years he had known and studied the work of Custer on the Channel Wing; and he wondered if a combination of control circulation, a method from which lift is generated utilizing jet of air to improve the aerodynamic characteristics of the wing, and the channel wing, could be the answer. Either of these systems, by themselves, could not provide the aircraft with the necessary characteristic he desired, but combining the two was seen by Bushnell as the way forward.

Custer CCW-5 (photo, via author)
Custer CCW-5 (photo, via author)

A new research program commenced in 1999 and lasted until 2004. The research focused on the Coanda Effect, named after its founder; Romania researcher Henri Coanda, who in August 1910 discovered that hot gases exiting a jet followed the contour of the plates installed to deflect it. Circulation Control follows a different path. Simply put it, circulation control works when compressed air is directed over a curve or leading edge to generate greater lift capacity. Researches believed that circulation control, could in the future rend obsolete moving surfaces on aircrafts. The next step in the developmental process for Circulation Control is the replacement of mechanical lift augmenters with air hoses to make the aircrafts lighter, quieter and maintenance friendly. For all of this to take effect, surface system needed to be introduced, and here is where the Channel Wing Concept comes into play.

Current computing systems used to measure fluid dynamics of aircrafts’ surfaces had established the feasibility that a Channel Wing configuration with enhance Circulation Control, could produce a serviceable and stable super-STOL platform. Wind tunnel testing and computer animations had confirmed the Channel Wing design payoffs in ways that Custer could not have done in his time. Custer clearly understood the airflow needed to generate lift could come from two different sources: the engine or the airframe forward motion. What he lacked was an understanding of what happened to the air stream once it hit the channel. The end result is turbulence. This is why both the CCW-1 and 5 failed to achieve major air-control properties. At low speeds, the flow of air is detached form the traveled surface; leading to the aircraft to lose differential pressure that is the cause of lift. At Custer’s time, there was no method accurate enough to calculate when this effect comes to play or how to design an aircraft that used this effect in its advantage. The solution: Circulation Control. One of the most challenging arenas for the CCWs models were the high angle of attack that the aircraft needed to be flown, a dangerous proposition because the pilot will temporarily loss the ability to see over the plane’s nose. Another problem was the lost of an engine. If the aircraft were to loss the use of one of its engines, the aircraft will be subject to high stall degrees and rolls, without the necessary energy to compensate for them. Circulation Control can solve this problem.

At present, Bushnell and his team had been pressing for sometime to design and aircraft that incorporates both concepts, but like Custer before, without much success. Skeptics’ rapidity pointed out that all the research data done during the past five decades had failed to produce a serviceable aircraft design, thus leading them to the conclusion that the concepts are incompatibles. The Channel Wing concept may need to wait until advances in technology can undisputable show that an airworthy aircraft can be achieve; but the Circulation Control concept is already been use by various countries in the design on unmanned air vehicles. Even a naval application was found for the concept. Submarines could use jets instead of conventional dive planes and rudders to change aspect ratios.

Custer’s idea was years ahead of his time, and seems today, that is still ahead of us. Further research and data collection maybe needed, but with the current military situation, a premium is been place on the ability of aircraft to perform short take-off and landing s procedures, its only a matter of time before the next great engineering breakthrough comes along and Custer’s idea will probably be at the center of it.

– Raul Colon

 

More information:
Custer Channelwing Website
The Official Custer Channel Wing Website
Les avions de Willard Custer
Mid-Atlantic Air Museum: CC-W-5
That Extra Little Lift