The increased power engines for the Me 262 were definitely coming. More on that latter.
The future, as the Luftwaffe saw it, was single engine fighters. Though designs intended only for a short time may need to remain in production longer.
Despite Messerschmitt's numerous methodical studies for various swept wing improvements to the Me 262 I am not aware of any Luftwaffe funding to turn these into metal though one might be done so for purposes of testing after some more test bed work. Messerschmitt was clearly aiming at breaking the sound barrier with HG series.
The Emergency Lightweight fighter competition (not to be confused with the He 162 Volks Jaeger or peoples fighter) was awarded to both Blohm Voss as well as Focke-Wulf for its Ta 183 "Huckbein" and came with a small production order, a few wings and body parts had been built. Blohm and Voss also received an award for its BV 212.03 (6 prototypes). I believe the Blohm Voss was superior due to the use of slats and flight testing of piston pushers using the unorthodox configuration.
Messerschmitt was about to put their P.1101 variable sweep test bed fighter to the air (it inspired the Bell X5). It could easily have been turned into a fighter. The Emergency Lightweight fighter program envisaged an interim version (Ta 183, BV212.03 or P.1101) and a latter optimal version Messerschmitt P.1112. The program was not decided but target production was October 1945.
Focke-Wulf Ta 183 Luft '46 entry Prototypes and small production order partially built
Blohm Voss BV P.212 Luft '46 entry Prototypes partially built
Messerschmitt Me P.1101 Luft '46 Entry Test bed about to take to air, convertible to fighter.
Messerchmitt Me P.1112 Luft '46 entry Optimal/Long term
P.1101 was about to take to the air had wings which could easily be replaced on the ground and their sweep and dihedral varied. It was to test wings with a variety of sweeps, slats, plan forms and wing profiles. The P.1101 would feed data into the important P.1112 program and the Me 262.
In terms of the Me 262 the main improvements would be to the engines, systems and likely small aerodynamic mods to 'area rule'.
Engine Improvements
The Jumo 004B4 had just introduced hollow air-cooled turbine blades, leading to an increase in engine life.
First improvement was the addition of a fuel control device called the "accelerator control valve" which used pressure sensors that measured the air mass flow rate and adjusted the fuel flow rate so that it was a ratio of the air flow. Engine RPM was still controlled by pilots throttle acting on the governor but now the flow was adjustable only within a range determined by the compressor air flow rate.
The benefit of this more precise control was the elimination of burnout damage from overheating during engine acceleration and reduction of flameout risk during rapid throttling down.
The new valve was to reach operational service by April 1945, a similar device was successfully introdroduced on the BMW 003. (see Anthony Kay)
The follow on engines were the Jumo 004C and Jumo 004D.
Jumo 004B4 thrust 898kg/1980lbs in service since November 1944.
Jumo 004C thrust 1000kg/2200lbs some used in test aircraft.
Jumo 004D thrust 1030kg,2300lbs production starting as the war ended in 1945.
The Jumo 004D clearly would have improved climb rate, acceleration, reduced take-off run.
Besides the Jumo 004 the
BMW 003 could also be used.
The BMW 003A2 could provide 800kg thrust and 900kg overload for 30 seconds. The follow on
BMW 003C with 900kg thrust and
BMW 003D with 1100kg thrust should be available in 1945 (for the C and possibly the D), smaller in diameter and length and more fuel efficient.
With these engines the aircraft would probably push itself to 1000kmh/600mph at its absolute Mach 0.86 limit at lower altitude (below 16000-20000 feet).
The smaller BMW 003C or D with similar or greater thrust might even raise Mach limit and would increase range about 10%.
A variant of the BMW 003A known as the BMW 003R had a rocket motor whose pumps were driven of the main engine shaft by clutch. With these engines an Me 262 was able to climb to 12000m in about 1.5 minutes. Clearly it could intercept 'instantly' any allied aircraft and bypass or evade any escort fighter. It used the same fuel as the jet engines but carried a belly pack of nitric acid oxidiser and some on board xylidine as a catalyst.
Beyond that was the Jumo 004H ,actually a scaled down Jumo 012, and included refinements such as blow of valves. Thrust was to be 1900kg, more than twice as much as the Jumo 004B. It had reached mock-up stage, photographs of the mockup are available and some parts had been made.
The Heinkel-Hirth HeS 011 engine, which is shown in graugeists HG-III was to have a thrust of 1300kg and was to be available for the Me 262. It used a 'diagonal flow' compressor that was basically a first stage centrifugal flow compressor that was faired so as to exist the air axially into a 3 stage axial flow compressor. Its low diameter and high resistance to turbulence lent it to installation in the wing near the wing root.
HeS 011A 1300kP / 2900lbs thrust. (Benching 1153kP in Jan 1945)
HeS 011B 1500kP / 3300lbs thrust.
HeS 011C 1700kP / 3800lbs thrust.
Should this engine become a success I would say HG-II would quickly be built. Note however the lightweight emergency fighter was dependant on this engine though prototypes would have flown with the Jumo 004.
Aerodynamic improvements.
Although Messerschmitt had investigated in wind tunnels Me 262 variants with swept wings I suspect they would wait until test bed data came in from P.1101.
The Germans were aware of the area rule and were starting to apply it, one proposal that was being investigated was the addition of small humps to area rule parts of the aircraft to reduce shock drag at high speed.
This would avoid the costly retooling needed for a new swept wing and an all new design might be better.
Yaw Damper.
Jets tend to have a high speed snaking. P-80, Meteor and Me 262 suffered to varying degrees.
A electronic yaw damper had been developed that took gyro rate information and used the derivative to kick opposite rudder. The Hs 129 yaw damper was developed by Dr. Karl Doetsch over the period 1942- 1944 at Berlin-Aldershot. Later "due to the bombing" he was transferred to Travemunde near Lubeck, where the Fighter Development Station was formed, and here he finished the work around January 1945, on what became the world's first series coupled yaw damper. Doetsch first thought of the idea after observing the effect of a misuse of the simple rudder course controIJers. If a heading change of more than 30° was dialled into these systems the demand limited and the system became just an angular rate control, giving a damping effect about the yaw axis. He first tested the concept himself in an Fw190 and later in an Me262. He was interviewed by British scientists, joined the RAE and a similar device was installed in the meteor.
Weapons System.
The EZ 42 gyro sight would be replaced by the similar EZ 45 and this would be linked to a radar ranging unit called FuG 248 "Eule" relieving the pilot of setting range. It would automatically calculate lead for the canon, R4M 55mm folding fin rockets and also R100 rockets (with either proximity warheads or timed shaped charges)
For the ground attack versions the ReVi site would be tied in with the TSA 2D toss bombing site. The pilot aimed at the target in a shallow dive as if strafing, the computer took in data from airspeed, radio or barometric altimeter, accelerometer. He pulled up and then the toss bombing site released the bombs at the correct point in the arc. Could also deliver cluster bombs and rockets. (Germans were already using cluster bombs with shaped charges.)
Armament
The Germans had experimented with a range of canon, choosing the powerful but short range MK 108 30mm canon over the longer ranged 20mm MG 151/20. However the MG 213 20mm revolver canon was becoming available and 4 such canon with their 50% greater firing rate over the MG 151/20, much longer range and reliability under G would become attractive. The EZ42 gyro sight showed itself able to snipe an enemy fighters canopy at 1000m at times. There was a 30mm version of this weapon known as MK 213C.
The R4M folding fin rocket had a proximity fuse that was shortly to be deployed (according to Adolf Galland). The much larger R100 had also been air fired 25 times. These could be accurately aimed because of the EZ42 Gyro site.
I do not hold out much advantage for the wire guided air to air missile the X4 but variants of it with terminal acoustic or infrared homing were practical. A non-rotating competitor of the X4 for the Henschel Hs 298 Could use a passive radar seeker known as MAX-P as well as an active radar version called MAX-A. It was built by blaupunkt and was working on the ground though its primary purpose was surface to air missiles.
Ejection Seat
Production Ejection seats were used on He 219, He 162 and Do 335 and would surely find their way into the Me 262. The pilot was valuable and could often be saved.