JUMO ENGINE CASTINGS
Easily the best known feature of those
listed in this section, the precision engine castings were first proposed,
then designed, by the late Steve Snyder. As an aeronautical engineer,
Snyder recognized that simply hanging a pair of J-85s on the Me 262
within oversized cowlings would create as many problems as it solved.
Differences in wing root forces, weight distribution, and the Center
of Gravity would have completely altered the characteristics of the
original Me 262. His solution may have been borne of necessity,
but it has emerged as one of the most innovative engineering feats in
the entire effort.
Detailed castings have been made from an
original Jumo engine, and all related accessory drive components,
gearboxes and pressure lines will be precisely duplicated for surface-mounting.
When the access panels are opened, bystanders will see a historically
accurate duplicate of a Jumo 004B engine. Concealed deep
within the casting, the modern powerplant will go all but completely
unnoticed.
Perhaps most significantly, the entire
assembly (when mated with the J-85) will closely duplicate the nacelle
weight of the original Jumo 004. In this respect, the
original performance characteristics of the aircraft will be faithfully
preserved.
LANDING GEAR IMPROVEMENTS
As the landing gear was known to be another
weak area on the original Me 262, a detailed analysis of landing gear
stresses was directed. This process revealed that a shock loading
was generated by the spin-up forces of the large, heavy main wheels,
which had to be reacted into by the wing landing gear attachment structure.
This placed a severe demand upon wing spar area and the airframe simply
had to absorb these forces. Over time, this would have had a devastating
effect upon the aircraft.
In part, this problem can be traced to
the history of the aircraft. As originally designed, the Me 262
was equipped with a standard tail wheel (in lieu of the nose wheel).
In the tail-dragger configuration, the
main gear was bolted directly onto the wing spar; however, the tricycle
modification resulted in the creation of a separate wing torque box
to be used as a mounting point. This torque box was susceptible
to damage, and very difficult to repair.
On the new Me 262s, this area has been
reinforced with additional structural features, and the project is considering
additional design changes that may further enhance the safety and longevity
of the landing gear. In addition to the wing box reinforcement,
the nose gear mounting point and strut assemblies have been greatly
improved. In short, the entire system has been strengthened by
a significant margin above what it was originally.
BRAKE SYSTEM IMPROVEMENTS
The braking systems of wartime German aircraft
usually left something to be desired, and the Me 262 was no exception.
Brake fading and/or complete system failures were a common complaint.
(For a brief description of such an incident in American hands,
see Ken
Holt's narrative on the Watson's
Whizzers pages.)
The notoriously ineffective nose wheel
brake has been eliminated altogether, although the original brake lines
will be duplicated for appearance. Meanwhile, the marginally
performing drum brakes on the main gear have been replaced by a cleverly-integrated
disc brake system. The improved disc brakes have been mounted within
the wheel hub assembly itself, and have the capacity to stop an aircraft
more than twice the weight of the Me 262.
THROTTLE PRESSURE SPRING (TPS) SYSTEM
Despite the fact that the nacelle weight
will be roughly equal to that of the original Me 262, the power available
to the pilot has still been significantly improved. Since the
characteristics of the airplane were well known at the 1,800 pound thrust
level, every effort has been made to duplicate this performance envelope,
and not create some "Super Me 262" class airplane. Still,
the fact remains that the increase in thrust is significant enough to
force us to consider some entirely new engineering aspects.
While a positive development in most respects,
the added power can present new problems of its own. For example,
an engine failure during a full power takeoff could quickly result in
an uncontrollable asymmetric thrust component. Our project engineers
understood this problem, and developed a simple method to control the
situation.
To address these issues and provide the
pilot an accurate indication of actual power settings, the project has
carefully modified the throttle assembly to be fitted with a throttle
pressure spring which provides a positive force indication of engine
RPM at 1,800 lbs. thrust. In other words, the pilot will know
when the maximum specification thrust levels of the Jumo 004
have been reached.
If the pilot desires additional power,
he may push the throttles beyond the spring loaded position, holding
them open against this spring pressure. The actual hard stop for
the throttles will be set at the J-85's maximum thrust setting, which
is projected to be around 2,400 to 2,500 lbs., as mounted. The
additional power is reserved for two operational regimes. On takeoff
roll, prior to liftoff, and during climb. Takeoff roll is initiated
with full power, but it is then reduced to the original Jumo takeoff
thrust level (1,800 lbs.) just prior to liftoff. The excess power
may be added once safe climb speeds of 260 Miles Per Hour are achieved.