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fgdata/Aircraft-yasim/b52-yasim.xml
curt 9d5aa83f83 Lee Elliot:
I've added reheat to the engines to simulate water injection and then tweaked
it so that it's just about possible to take off with the full fuel load/ferry
configuration (a little under the mtow - 420,000lbs vs 450,000lbs).

It's interesting to note that the normal combat tow for the F model was
291,570lbs - equivilent to a fuel load of about 0.46 (this would actually
leave you with more fuel than in real life because some of that weight would
be the weapons load but here it's fuel)

Anyway, I've added all this info to the readme and explained some of the
reasoning behind the fdm there.

It still doesn't reach the correct altitudes, and certainly not with a full
fuel load, but it starts getting into the right ball park at combat tow.
2003-08-14 18:57:44 +00:00

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<!-- B52-F yasim config.
Notes.
B-52F with full fuel load, no weapon load.
This config cannot be regarded as an accurate representation
of a B-52F. I've used the real numbers, where I've been able
to find them, but a lot of this config is semi-educated
guesswork. I think all the bits are in the right places but
many of the numbers were obtained either by measuring a h/c
of the 3-view I used as a template for modelling or by reading
them out of my 3d modeller.
The B52s had all moving tailplanes (9 deg up & 4 deg down) and
these cannot be represented correctly using yasim at the moment,
so in that respect this config is definitely a hack.
Lee Elliott. leee-fgfs@spatial.freeserve.co.uk
-->
<airplane mass="173599">
<!-- Approach configuration -->
<approach speed="100" aoa="1.0">
<control-setting axis="/controls/engines/engine[0]/throttle" value="0.4"/>
<control-setting axis="/controls/engines/engine[1]/throttle" value="0.4"/>
<control-setting axis="/controls/engines/engine[2]/throttle" value="0.4"/>
<control-setting axis="/controls/engines/engine[3]/throttle" value="0.4"/>
<control-setting axis="/controls/engines/engine[4]/throttle" value="0.4"/>
<control-setting axis="/controls/engines/engine[5]/throttle" value="0.4"/>
<control-setting axis="/controls/engines/engine[6]/throttle" value="0.4"/>
<control-setting axis="/controls/engines/engine[7]/throttle" value="0.4"/>
<control-setting axis="/controls/engines/engine[0]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[1]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[2]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[3]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[4]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[5]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[6]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[7]/afterburner" value="0.0"/>
<control-setting axis="/controls/flight/flaps" value="1.0"/>
<control-setting axis="/controls/flight/spoilers" value="0.0"/>
<control-setting axis="/controls/gear/gear-down" value="1"/>
</approach>
<!-- Cruise configuration -->
<!-- I found the following performance figures
638 mph (554 kt) @ 21000 ft
570 mph (495 kt) @ 46500 ft
523 mph (454 kt) cruising speed (no alt specified)
The service ceiling at combat weight (291570 lbs) is 46700 ft and I
assume that's at the cruise speed (454 kt)
I've not been able to get a solution that solves using 495 kt @ 46500 ft
and using the figure of 554 kt @ 21000 ft results in the a/c not being
able to climb nearly high enough so the numbers specified are currently
the best compromise I've found so far.
-->
<cruise speed="554" alt="21000">
<control-setting axis="/controls/engines/engine[0]/throttle" value="0.6"/>
<control-setting axis="/controls/engines/engine[1]/throttle" value="0.6"/>
<control-setting axis="/controls/engines/engine[2]/throttle" value="0.6"/>
<control-setting axis="/controls/engines/engine[3]/throttle" value="0.6"/>
<control-setting axis="/controls/engines/engine[4]/throttle" value="0.6"/>
<control-setting axis="/controls/engines/engine[5]/throttle" value="0.6"/>
<control-setting axis="/controls/engines/engine[6]/throttle" value="0.6"/>
<control-setting axis="/controls/engines/engine[7]/throttle" value="0.6"/>
<control-setting axis="/controls/engines/engine[0]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[1]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[2]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[3]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[4]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[5]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[6]/afterburner" value="0.0"/>
<control-setting axis="/controls/engines/engine[7]/afterburner" value="0.0"/>
<control-setting axis="/controls/flight/flaps" value="0.0"/>
<control-setting axis="/controls/flight/spoilers" value="0.0"/>
<control-setting axis="/controls/gear/gear-down" value="0"/>
</cruise>
<cockpit x="-2.2" y="0.0" z="2.0"/>
<fuselage ax="0" ay="0" az="0" bx="-49.05" by="0" bz=".64"
width="3.2" taper="0.5" midpoint="0.3"/>
<!-- Wing incidence was set at 6 degrees because the tandem u/c meant
that the aircraft couldn't rotate in the conventional fashion. I
found lots of references to the sweep angle of 35 degrees but
none of them stated the chord point for it i.e. leading edge or
quarter-chord. As yasim uses mid-chord I've subtracted 0.5 degree
as a fudge factor.
Yasim also only allows for one [real] flap entry per wing so I've
used a single spane but reduced it's length by the width of the
aileron, which I've located outboard of the flaps.
-->
<wing x="-16.0" y="1.6" z="1.2" taper="0.4" incidence="6"
length="31.1" chord="10.0" sweep="34.5" dihedral="-1.0" camber="0.16">
<stall aoa="18.0" width="3" peak="1.3"/>
<flap0 start="0.0" end="0.62" lift="1.45" drag="2.2"/>
<flap1 start="0.62" end="0.7" lift="1.3" drag="1.3"/>
<spoiler start="0.5" end="0.75" lift="0.0" drag="1.8"/>
<control-input axis="/controls/flight/flaps" control="FLAP0"/>
<control-input axis="/controls/flight/aileron" control="FLAP1" split="true"/>
<control-input axis="/controls/flight/spoilers" control="SPOILER"/>
<control-output control="FLAP0" side="left" prop="/surface-positions/left-flap-pos-norm"/>
<control-output control="FLAP0" side="right" prop="/surface-positions/right-flap-pos-norm"/>
<control-output control="FLAP1" side="left" prop="/surface-positions/left-aileron-pos-norm"/>
<control-output control="FLAP1" side="right" prop="/surface-positions/right-aileron-pos-norm"/>
<control-output control="SPOILER" side="left" prop="/surface-positions/left-spoiler-pos-norm"/>
<control-output control="SPOILER" side="right" prop="/surface-positions/right-spoiler-pos-norm"/>
<control-speed control="FLAP0" transition-time="45"/>
<control-speed control="FLAP1" transition-time="0.5"/>
<control-speed control="SPOILER" transition-time="0.5"/>
</wing>
<!-- The hstab/elevators are nearly deltas ao I've given them a high
stall AoA figure.
-->
<hstab x="-41.5" y="1.0" z="0.8" taper="0.25" effectiveness="1.0"
length="7.5" chord="7.5" sweep="40.0" dihedral="0.0" camber="0.01">
<stall aoa="25.0" width="3" peak="1.5"/>
<flap0 start="0" end="1" lift="1.3" drag="1.4"/>
<control-input axis="/controls/flight/elevator" control="FLAP0"/>
<control-input axis="/controls/flight/elevator-trim" control="FLAP0"/>
<control-output control="FLAP0" prop="/surface-positions/elevator-pos-norm"/>
<control-speed control="FLAP0" transition-time="0.5"/>
</hstab>
<vstab x="-41.5" y="0" z="2.0" taper="0.4"
length="8.5" chord="7.5" sweep="35.0">
<stall aoa="20.0" width="3" peak="1.5"/>
<flap0 start="0" end="1" lift="1.15" drag="1.3"/>
<control-input axis="/controls/flight/rudder" control="FLAP0" invert="true"/>
<control-output control="FLAP0" prop="/surface-positions/rudder-pos-norm"/>
</vstab>
<!-- Engine entries -->
<!-- I've used the dry thrust rating of the J57-P-43WA turbojet (11200 lb)
here instead of the wet-thrust (13500 lb). This will make take offs a
little more sluggish but is about equivilent of a B-52B with wet-thrust.
This model is a little heavier though.
I couldn't find a weight for the engines and have guessed at 4000lb
-->
<!-- Left wing engines -->
<!-- Left Outer Left -->
<jet x="-23.0" y="20.0" z="-1.0" mass="4000" tsfc="0.7" thrust="11200" afterburner="13500">
<control-input axis="/controls/engines/engine[0]/throttle" control="THROTTLE"/>
<control-input axis="/controls/engines/engine[0]/afterburner" control="REHEAT"/>
</jet>
<!-- Left Outer Right -->
<jet x="-23.0" y="18.0" z="-1.0" mass="4000" tsfc="0.7" thrust="11200" afterburner="13500">
<control-input axis="/controls/engines/engine[1]/throttle" control="THROTTLE"/>
<control-input axis="/controls/engines/engine[0]/afterburner" control="REHEAT"/>
</jet>
<!-- Left Inner Left -->
<jet x="-15.0" y="12.0" z="-1.0" mass="4000" tsfc="0.7" thrust="11200" afterburner="13500">
<control-input axis="/controls/engines/engine[2]/throttle" control="THROTTLE"/>
<control-input axis="/controls/engines/engine[0]/afterburner" control="REHEAT"/>
</jet>
<!-- Left Inner Right -->
<jet x="-15.0" y="10.0" z="-1.0" mass="4000" tsfc="0.7" thrust="11200" afterburner="13500">
<control-input axis="/controls/engines/engine[3]/throttle" control="THROTTLE"/>
<control-input axis="/controls/engines/engine[0]/afterburner" control="REHEAT"/>
</jet>
<!-- Right wing engines -->
<!-- Right Inner Left -->
<jet x="-15.0" y="-10.0" z="-1.0" mass="4000" tsfc="0.7" thrust="11200" afterburner="13500">
<control-input axis="/controls/engines/engine[4]/throttle" control="THROTTLE"/>
<control-input axis="/controls/engines/engine[0]/afterburner" control="REHEAT"/>
</jet>
<!-- Right Inner Right -->
<jet x="-15.0" y="-12.0" z="-1.0" mass="4000" tsfc="0.7" thrust="11200" afterburner="13500">
<control-input axis="/controls/engines/engine[5]/throttle" control="THROTTLE"/>
<control-input axis="/controls/engines/engine[0]/afterburner" control="REHEAT"/>
</jet>
<!-- Right Outer Left -->
<jet x="-23.0" y="-18.0" z="-1.0" mass="4000" tsfc="0.7" thrust="11200" afterburner="13500">
<control-input axis="/controls/engines/engine[6]/throttle" control="THROTTLE"/>
<control-input axis="/controls/engines/engine[0]/afterburner" control="REHEAT"/>
</jet>
<!-- Right Outer Right -->
<jet x="-23.0" y="-20.0" z="-1.0" mass="4000" tsfc="0.7" thrust="11200" afterburner="13500">
<control-input axis="/controls/engines/engine[7]/throttle" control="THROTTLE"/>
<control-input axis="/controls/engines/engine[0]/afterburner" control="REHEAT"/>
</jet>
<!-- Landing Gear -->
<!-- Front Left -->
<gear x="-13.2" y="2.0" z="-2.9" retract-time="7" compression="1.0">
<control-input axis="/controls/flight/rudder" control="STEER" square="true"/>
<control-input axis="/controls/gear/gear-down" control="EXTEND"/>
<control-input axis="/controls/gear/gear[0]/wheel[0]/brake" control="BRAKE"/>
<control-input axis="/controls/gear/gear[0]/wheel[1]/brake" control="BRAKE"/>
<control-input axis="/controls/gear/parking-brake" control="BRAKE"/>
<control-speed control="EXTEND" transition-time="7"/>
<control-speed control="BRAKE" transition-time="0.7"/>
<control-output control="EXTEND" prop="/gear/gear[0]/position-norm"/>
</gear>
<!-- Front Right -->
<gear x="-13.2" y="-2.0" z="-2.9" retract-time="7" compression="1.0">
<control-input axis="/controls/flight/rudder" control="STEER" square="true"/>
<control-input axis="/controls/gear/gear-down" control="EXTEND"/>
<control-input axis="/controls/gear/gear[1]/wheel[0]/brake" control="BRAKE"/>
<control-input axis="/controls/gear/gear[1]/wheel[1]/brake" control="BRAKE"/>
<control-input axis="/controls/gear/parking-brake" control="BRAKE"/>
<control-speed control="EXTEND" transition-time="7"/>
<control-speed control="BRAKE" transition-time="0.7"/>
<control-output control="EXTEND" prop="/gear/gear[1]/position-norm"/>
</gear>
<!-- Rear Left -->
<gear x="-28.0" y="2.0" z="-2.9" retract-time="7" compression="1.0">
<control-input axis="/controls/gear/gear-down" control="EXTEND"/>
<control-input axis="/controls/gear/gear[2]/wheel[0]/brake" control="BRAKE"/>
<control-input axis="/controls/gear/gear[2]/wheel[1]/brake" control="BRAKE"/>
<control-input axis="/controls/gear/parking-brake" control="BRAKE"/>
<control-speed control="EXTEND" transition-time="7"/>
<control-speed control="BRAKE" transition-time="0.7"/>
<control-output control="EXTEND" prop="/gear/gear[2]/position-norm"/>
</gear>
<!-- Rear Right -->
<gear x="-28.0" y="-2.0" z="-2.9" retract-time="7" compression="1.0">
<control-input axis="/controls/gear/gear-down" control="EXTEND"/>
<control-input axis="/controls/gear/gear[3]/wheel[0]/brake" control="BRAKE"/>
<control-input axis="/controls/gear/gear[3]/wheel[1]/brake" control="BRAKE"/>
<control-input axis="/controls/gear/parking-brake" control="BRAKE"/>
<control-speed control="EXTEND" transition-time="7"/>
<control-speed control="BRAKE" transition-time="0.7"/>
<control-output control="EXTEND" prop="/gear/gear[3]/position-norm"/>
</gear>
<!-- Left Wing -->
<gear x="-31.0" y="23.0" z="-2.0" retract-time="5" compression="2.5">
<control-input axis="/controls/gear/gear-down" control="EXTEND"/>
<control-speed control="EXTEND" transition-time="5"/>
<control-output control="EXTEND" prop="/gear/gear[4]/position-norm"/>
</gear>
<!-- Right Wing -->
<gear x="-31.0" y="-23.0" z="-2.0" retract-time="5" compression="2.5">
<control-input axis="/controls/gear/gear-down" control="EXTEND"/>
<control-speed control="EXTEND" transition-time="5"/>
<control-output control="EXTEND" prop="/gear/gear[5]/position-norm"/>
</gear>
<!-- Fuel tanks -->
<!-- Total fuel for the F model was 41553 gal incl the external tanks
There are a total of ten internal tanks, three located in the wings
and four along the top of the fuselage above the bomb bay. I don't
know what percentage was held in the wings vs. the fuselage but I'm
guessing that more was held in the fuselage tank than half of the
wing tank total.
There are also two external wing tanks holding 3000 gal each.
fgfs seems to convert gal to lbs using a ratio of 1:6 giving a total
of 249318 lb of fuel, of which 18000 lb are in each external tank.
That leaves 213318 of fuel to be distributed in the wings and
fuselage.
-->
<tank x="-20.0" y="10.0" z="2.0" capacity="70000"/>
<tank x="-20.0" y="-10.0" z="2.0" capacity="70000"/>
<tank x="-20.0" y="0.0" z="2.3" capacity="73318"/>
<tank x="-30.0" y="28.0" z="1.5" capacity="18000"/>
<tank x="-30.0" y="-28.0" z="1.5" capacity="18000"/>
<!-- This is to level the aircraft on the ground
-->
<ballast x="-4.0" y="0" z="0" mass="20000"/>
</airplane>