The Hawker P.1216
Posted 10-06-2007 at 12:40 AM by Sentinel Chicken
Tags p.1216
One of the more interesting lines of fighter aircraft design came about from internal studies in the United Kingdom at BAe (British Aerospace) Kingston, the home of Hawker Siddeley's fighter design house that was once led by the legendary Sir Sydney Camm. He is best known for his Hawker fighter designs from the 1930s Hawker Fury, the legendary Hawker Hurricane of the Second World War, the post war figther jets Hawker Sea Hawk and the graceful Hawker Hunter. But it was his work with the Hawker P.1127 that would prove to be one of his fitting legacies to military aviation as the Hawker P.1127 ultimately became the Harrier "jump jet" that proved VSTOL combat aircraft were practical and flexible.
Through out the 1970s the designers and engineers at Kingston worked on supersonic follow-ons to the Harrier and their work incorporated what is called PCB- plenum chamber burning- the burning of fuel afterburner style in the dense and cooler air of the fan bypass duct that fed the foward set of vectoring nozzles on the Pegasus engine that powered the Harrier family. A Harrier equipped with PCB was even tested in a ground rig in the 1980s to validate the concept.
The design of the Hawker P.1216 was unique to say the least and I'll digress here a bit to show how BAe Kingston arrived at the layout of the P.1216 by showing some of the earlier predecessor designs:
^This is the P.1205 which looks a lot like a cross between the Harrier and the F-16 Fighting Falcon. Several design features should be noted- first, the deep fuselage which allowed the Pegasus engine to changed by dropping it below. On the current Harrier family, changing the Pegasus is a nightmare as you have to first remove the wing and then lift the engine out of the fuselage. By providing a deeper fuselage and moving to a tricycle landing gear with the main gear in wing pods, maintenance becomes much easier. But dividing the jet efflux into four parts was not only less efficient than a conventional fighter engine, it also subjected the aft fuselage to a lot of heat and vibration which either shortened the life of the structure or required a stronger and heavier structure- and you all know that excess weight can kill a VSTOL fighter.
Next came this futuristic design:
^This was the Hawker P.1214 and it figured prominently in BAe's promotional materials of the early 1980s thanks to it's futuristic shape. The engineers and designers got around the inherently high drag of a deep fuselage by basically splitting the aft fuselage and moving each half to the wings to become tail booms/wing pods/plyons. The Pegasus engine changed into a "three-poster" with PCB nozzles forward and a single aft nozzle. By effectively "divorcing" the fuselage structure from jet exhaust, the engine could be made to operate more efficiently and the airframe had a lot less drag as a result.
This was the final refinement of the design, the P.1216:
The foward swept wing of the P.1214 ultimately proved impractical and the design was refined even further with a conventional swept-wing with wingtip missile stations. The booms held not only the tail assembly, but also the main landing gear, some fuel tanks, weapons pylons, and in some design versions, the aircraft's cannon (the RAF favoring a 27mm Mauser cannon in the front section of each boom/wing pod).
In Tony ****ler's impressive book British Secret Projects: Jet Fighters Since 1950, he devotes an entire chapter to the VSTOL fighter design work of BAe Kingston. In reference to the P.1216 and its predecessor designs, he notes that in an unbroken line of engineering and design work in vertical-take off and landing fighters that go back to the P.1127 of 1957 to the P.1216 of the 1980s, BAe Kingston found no other more practical and efficient engine concept than thrust vectoring and the P.1216 was in a sense, the ultimate expression this work that stretched nearly 30 years. The addition of PCB to the P.1216 gave it supersonic peformance (keeping in mind the X-35B was the first practical supersonic VSTOL that is to be soon as the F-35B JSF for the Royal Navy and USMC) and a capability on par with current fighter designs of the day. With PCB, the P.1216 was not only supersonic, but it didn't need an afterburner as it's a very thermodynamically efficient system. In flight, the PCB lit is only 2/3 the fuel cost of a conventional afterburner and in vertical flight mode the additional thrust boost is in the region of 35-40 percent.
With the PCB arrangement and three-poster Pegasus engine, the unique forked tail layout of the P.1216 makes much more sense. With no aft fuselage to worry about, the aft nozzles of the Pegasus can be consolidated in a much more efficient and powerful single nozzle that still is fully vectorable. The P.1216 occupied a good deal of design work at BAe Kingston in the first half of the 1980s, but Britain and the RAF's fighter future would lay in the Eurofighter Typhoon (a decision still considered controversial in aviation circles)- sadly, an aircraft that would appear to possess none of the P.1216's operational flexibility that the Harrier family has consistently proven since entering service over 30 years ago.
Through out the 1970s the designers and engineers at Kingston worked on supersonic follow-ons to the Harrier and their work incorporated what is called PCB- plenum chamber burning- the burning of fuel afterburner style in the dense and cooler air of the fan bypass duct that fed the foward set of vectoring nozzles on the Pegasus engine that powered the Harrier family. A Harrier equipped with PCB was even tested in a ground rig in the 1980s to validate the concept.
The design of the Hawker P.1216 was unique to say the least and I'll digress here a bit to show how BAe Kingston arrived at the layout of the P.1216 by showing some of the earlier predecessor designs:
^This is the P.1205 which looks a lot like a cross between the Harrier and the F-16 Fighting Falcon. Several design features should be noted- first, the deep fuselage which allowed the Pegasus engine to changed by dropping it below. On the current Harrier family, changing the Pegasus is a nightmare as you have to first remove the wing and then lift the engine out of the fuselage. By providing a deeper fuselage and moving to a tricycle landing gear with the main gear in wing pods, maintenance becomes much easier. But dividing the jet efflux into four parts was not only less efficient than a conventional fighter engine, it also subjected the aft fuselage to a lot of heat and vibration which either shortened the life of the structure or required a stronger and heavier structure- and you all know that excess weight can kill a VSTOL fighter.
Next came this futuristic design:
^This was the Hawker P.1214 and it figured prominently in BAe's promotional materials of the early 1980s thanks to it's futuristic shape. The engineers and designers got around the inherently high drag of a deep fuselage by basically splitting the aft fuselage and moving each half to the wings to become tail booms/wing pods/plyons. The Pegasus engine changed into a "three-poster" with PCB nozzles forward and a single aft nozzle. By effectively "divorcing" the fuselage structure from jet exhaust, the engine could be made to operate more efficiently and the airframe had a lot less drag as a result.
This was the final refinement of the design, the P.1216:
The foward swept wing of the P.1214 ultimately proved impractical and the design was refined even further with a conventional swept-wing with wingtip missile stations. The booms held not only the tail assembly, but also the main landing gear, some fuel tanks, weapons pylons, and in some design versions, the aircraft's cannon (the RAF favoring a 27mm Mauser cannon in the front section of each boom/wing pod).
In Tony ****ler's impressive book British Secret Projects: Jet Fighters Since 1950, he devotes an entire chapter to the VSTOL fighter design work of BAe Kingston. In reference to the P.1216 and its predecessor designs, he notes that in an unbroken line of engineering and design work in vertical-take off and landing fighters that go back to the P.1127 of 1957 to the P.1216 of the 1980s, BAe Kingston found no other more practical and efficient engine concept than thrust vectoring and the P.1216 was in a sense, the ultimate expression this work that stretched nearly 30 years. The addition of PCB to the P.1216 gave it supersonic peformance (keeping in mind the X-35B was the first practical supersonic VSTOL that is to be soon as the F-35B JSF for the Royal Navy and USMC) and a capability on par with current fighter designs of the day. With PCB, the P.1216 was not only supersonic, but it didn't need an afterburner as it's a very thermodynamically efficient system. In flight, the PCB lit is only 2/3 the fuel cost of a conventional afterburner and in vertical flight mode the additional thrust boost is in the region of 35-40 percent.
With the PCB arrangement and three-poster Pegasus engine, the unique forked tail layout of the P.1216 makes much more sense. With no aft fuselage to worry about, the aft nozzles of the Pegasus can be consolidated in a much more efficient and powerful single nozzle that still is fully vectorable. The P.1216 occupied a good deal of design work at BAe Kingston in the first half of the 1980s, but Britain and the RAF's fighter future would lay in the Eurofighter Typhoon (a decision still considered controversial in aviation circles)- sadly, an aircraft that would appear to possess none of the P.1216's operational flexibility that the Harrier family has consistently proven since entering service over 30 years ago.
