F-35:The $380 billion mistake II

 There is one blog if front and one after this blog.

   Hopefully, part I has been read.  In 2, it will be noted that increasing the size of the wing cross-section greatly increases the available internal wing volume for fuel storage.  This can eliminate the need for external fuel tanks.  It would be necessary to have a mechanism for dumping the excess fuel when entering combat.  One means would be to have a tank of compressed nitrogen to overpressure the fuel tank forcing the fuel out through exit lines.

   Another point that must be mentioned is the need to change direction of travel.  This requires the wings to be rotated from horizontal to vertical.  When doing this the wings act as large paddles whose turning is resisted by the air.  In addition , when plunging a wing, such as the left wing dropping to execute a left turn, the lift of the wing increases when being plunged under compressible flow. This increase in lift must be further overcome by rotating forces supplied by ailerons.

   This is where torsional stiffness becomes so important.  In order to maintain a high rate of rotation, the wing must remain rigid in sectional rotation.  When a wing is to be lifted, the aileron must be lowered to produce lift, but the aileron, located at the rear of the wing, is located in back of the torsional center of rotation.  So, the lift at the rear causes the rear of the wing to rise and forcing the front edge downwards.  Wing lift increases with increasing angle of the front edge, decreasing the leading edge angle decreases the wing lift.

This means that lowering the aileron to increase wing lift lowers the leading edge, decreasing wing lift, if the aileron manages to negate its own lift, this is known as wing reversal.  Back in World War II, the Japanese had a fighter that the U.S. called a Zero.  To save weight the wings were lightly built, at the beginning of the war the wings were also lengthened to increase range.  Near its top speed , it came close to wing reversal, owing to light construction it could turn quickly but it was slow in going into a turn or changing direction.  U.S. fighters had a maneuver called a Thach weave, it involved two U.S. fighters turning away from each other, one right, the other left, and then turning back towards each other.  Zeros had difficulty following the changes in direction, wallowing in their turns, giving the U.S. fighters a chance to shoot at the Zeros from the front as they passed.  The Japanese lost a lot of battles.

   Torsional stiffness involves wing beams, spars, that extend form the fuselage to the wing tips, combined with the wing skin, they form a beam structure.  It is similar to a diving board.  The various spars are similar to a group of diving boards side- to-side.  If, for instance, the diving board deflects by 1 inch if 100 lbs is placed upon it, that force would be multiplied by the distance to the torsional center to determine stiffness, the further from the center of torsion, the greater the stiffness it produces.  There is one problem.  In order to transmit the force through the distance to the torsional center there needs to be another beam connecting them.  If the diving board deflects 1 inch and the beam to the torsional center deflects 1 inch, the total deflection is two inches, making the wing less stiff.  It is a two dimensional matrix.  For low aspect ratio wings, the wing bends into a potato chip shape, deflecting very little along the fuselage and more in the center than at the edges of the wings.  Having a longer cord wing puts more stiffness further from the torsional center but also increases the front-to-back beam length making that beam more flexible, reducing the stiffness to the center-of-torsion.  Over all the bigger wing tends to be stiffer.

  One of the difficulties when an airplane begin to spin, rotating like a frisbee, is that the horizontal stabilizer, tailplane, can create an aerodynamic shadow, blocking the vertical stabilizer.  This is the principal reason for strakes to be fitted.

   The landing gear would be carried by the lifting wing on booms, 4.  

The landing gear would be in front of an behind the fighter wing, giving four sets of wheels and struts.

   For landing, The forward landing gear would be extended to allow all four wheels to land at eh same time.  This is necessary because the center of mass would be between the forward and rear gear and, if only the rear gear struck the ground, the aircraft would rotate downward onto the front gear causing a hard landing.

   For take-offs, a forward wing could be built onto the wing, 7.  The forward wing would produce lift to raise the angle-of-attack to increase lift for take-off.  Whatever weight cannot be lifted by the forward wing must be lifted by the forward landing gear.  The one problem is that flow from wings flows backwards and downwards and flow form the forward wing would be ingested into the fighter plane's engines.  This is really bad.  Turbulent flow would induce additional stresses into the compressor of the engines.  Worse, maintaining combustion in a turbine engine is not simple.  In fact, the people who know how to build combustors  for turbine engines wear long black capes with hoods  and Runic lettering written on the back.  Designing them requires a lot of science, engineering and a magic touch.  Having pulsating flows can cause the engines to flame out.

    Most maintenance would be done with the fighter and wing connected.  For additional work, a cart can be slid beneath the fighter and the fighter's weight lifted.  The wing and fighter can then be slightly separated for access.  If ti is necessary to completely separate them, a heavy vehicle would be driven to the front of the wing and attached to provide a counter-balance, the rear landing gear would then be raised and the fighter withdrawn backwards, 6.

   In 7, the wing end can be folded down to reduce space for parking and to allow it to be placed into an aircraft shelter.

   The reason for the fighter to be built in two pieces is because high- speed, compressible flow, is essentially a different fluid from low-speed incompressible flow.  An attempt to deal with this phenomenom was variable geometry, also known as the swing wing, 8. It was an incredibly stupid idea, it adds mass to the aircraft and makes a flexible wing, both of which are unwanted in military aircraft.  Any competent engineer should have dismissed the idea within an hour.  Instead it took twenty years for it to be realized that it did not work.

   8b, shows the difference in turning radius between 9gs and 12gs.  At 600mph, 9g is a 2800 ft radius and 12g is 2100 ft.

   This is important for the F-35.  The idea of the F-35 is that it can fire missiles before it is seen.  The missiles are called high-probability-of- intercept, meaning they are likely to hit their target.  But that is for 9gs, at 12gs they would be high-probability-of-miss.  In order to hit a 12g target, the winglets of the missile would have to be enlarged adding wight, additionally, the body of the missile would have to be made heavier because of higher stresses.  The only way that weight can be compensated is by reducing the weight of fuel.  The drag of the missile would increase with the larger winglets and, combined with the reduction in fuel would result in a shorter range.  The idea with the F-35 is that missiles can be fired beyond-visual-range (BVR), meaning the missile are fired before the plane is seen.  The reduced range would at least reduce the margin of safety and in a turning fight a 9g fighter could not fight a 12g fighter, it would be suicide. 

   The one limitation to a 12 g fighter is power-of -maneuver.  The aircraft engines must replace the energy from drag in maneuvers or the fighter will slow down, eventually losing maneuvering ability.  

    In 8 c,d,e show the connection between boom and fighter.  Two trunnions would be inserted into the end of the boom to connect the airframes and still allow for angular movement of the boom end

  In 9a, a bucket is swung on a rope.  If a water balloon is placed in the bottom of the bucket it will splay out, if the bucket is spun it will splay out even further.  But, if the bucket is filled with water. the balloon will stay round no matter how hard the bucket is spun, as the pressure inside and outside the balloon will be equal, b.  The human body is basically a water balloon.  In the 1960s, engineers at the Naval Air Warfare Center in Warminster, Pa.  had a centrifuge for spinning people in g experiments.  One day they got bored and put a fish tank with fish on the centrifuge.  They spun the fish to 40gs and it did not care.  If the fish is under 1 foot of water, 40 gs would be like 40 feet of water, no problem for a fish.  They then built what they called "the iron maiden", an aluminum tank in which they could place a person before filling it with water and spinning the people to 32 gs.  Normally,people would have trouble at 9 gs when oriented top to bottom, as the blood drains from the head to the legs.  With the water the subjects had no difficulties.  In World War II water filled pants were tried for anti-g.  They worked but they weighed 50 lbs.  A suit similar to an astronaut suit with a scuba hood could be filled with water after a pilot climbs into a cockpit to withstand gs. No one ever tried building a suit like this.

  If the pilot ejects, the suit can work as a survival capsule in water.  To further protect the pilot an additional neoprene hood with clear flexible plastic mask could be worn. It would have a snorkle with an opening maybe 4 inches by 1/4 inch.  It would have slits in the hard plastic and an interior flexible membrane, the membrane would collapse under water pressure to prevent aspiration of water, it would spring open when the water drops.  Seawater weighs 64 lbs per cubic foot, water 2 inches deep would produce 10 lbs per square foot pressure.  Breathing at 30 feet per second would produce 1 lb per square foot.  A similar snorkle could be added to commercial survival suits, p.

   The ability to make automatic connection between fighter and wing was available in 1975, every fighter built since then has been obsolete.  The entire air force needs to be scrapped and replaced and the F-35 is idiocy.