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# FSX VTOL Control gauge for Hadi Tahir's YAK-141                      #
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#                     By Rob Barendregt                 11 June 2008   #
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This package contains a VTOL control gauge for the Hadi Tahir's YAK-141,
which is available as file fsyak141.zip on www.flightsim.com.
Prior installation and correct operation of this package in FSX is required !

 
What the VTOL gauge essentially does: when VTOL-control is activated, it overrides
the normal FS aircraft flightdynamic calculations, so complete control of the
aircraft is done by intelligent gauge code (with input from the pilot using
the normal flightcontrols like rudder, ailerons, throttle and elevator axis).
The effects control gauge adds a lot of controlled, visible effects to the aircraft.

Functionality (for details, see below):
- Smooth and stable VTOL/Hover capabilities, with pilot-controlled ascent/descent
  rate, longitudinal and lateral speed, heading, pitch and bank.
- Works under ALL wind conditions; even with a tailwind, it can fly backwards !
- Does NOT influence the aircraft's normal flight characteristics: the gauge
  is only active when the nozzle is rotated at 90 degrees.


*************************** IMPORTANT **************************
1 This solution also requires prior installation of Peter Dowson's FSUIPC:
  FSUIPC.dll (V4.2.0.0 or later, registered or unregistered).
  You can download and install the lastest version of FSUIPC at:
      http://www.schiratti.com/dowson.html
2 When loading the aircraft for the first time, you might be asked to "trust" Peter
  Dowson's FSUIPC and Doug Dawson's modules; if you "trust" them, and also say "Yes" 
  when asked to all modules from Peter and Doug, you will never asked again.
3 If VTOL doesn't appear to work properly:
There may be several causes.
The new SimConnect interface in FSX sometimes doesn't work properly (known bugs)
Moreover, there are some known problems with SImConnect/FSUIPC w.r.t virusscanners and
firewalls; SimConnect communicates via TCP/IP with FSX !
If you experiance these problems, check the FSUIPC website/forum for solutions; there
are several threads about this subject.
To check if SimConnect/FSUIPC is working properly: check if your Menu bar in FSX
contains an item "Addons", with "FSUIPC" in it.
If this is OK, check the following:
- The green Nozzle needle in VTOL Control gauge should be at 90 degrees (ie. full Flaps)
- The aircraft weight should NOT exceed 36000 lbs for VTOL operation.
  Reduce fuel/payload if needed.


Installation
============
1. Make sure you have installed the original YAK-141 to it's default location, and
   that you have downloaded and installed the FSUIPC.dll module.

2. Extract the contents of this zipfile to your root FSX folder, using the option
   "use folder name". This will place all files in their correct location (see their
   pathnames in the zip file, relative to the FSX root folder).
   Overwrite the original aircraft.cfg and panel.cfg files with the ones included.




Detailed functionalty of the "VSTOLControlIPC.xml" gauge
========================================================
This gauge consists of two parts:
- A functional part (_Func)
  This gauge should only be defined ONCE.
- A display/click part (_Display)
  This gauge can be defined multiple times, e.g. in 2D Cockpit and in VC.

The _Display gauge has a clickable bitmap with tooltips.
It displays:
- The FSX "flaps" position:
  - White Needle: the Flaps position (flaps-position 0-5, 0-50 degrees)
  - Green Needle: the Nozzle position (flaps-position 5-7, 0-90 degrees)
- Other info:
  - Short Red Needle: the winddirection, relative to the aircraft.
  - Top-Left number: Radio Altitude, in feet.
  - Top-Center number: Windspeed, in knots.
  - Top-Right number: Pitch, in degrees.

Beside using the normal keys/buttons to in/decrease "flaps", you can also
click the gauge. See ToolTips.
- TopLeft:     Display/Hide RadioAltitude info.
- TopRight:    Display/Hide Pitch info.
- TopCenter:   Display/Hide Wind info.
- BottomLeft:  Increment flaps/nozzles.
- BottomRight: Decrement flaps/nozzles.
- An Overweight indicator; when the red light is On, the aircraft exceeds max.
  weight for VTOL operation (36000 lbs); dump fuel or payload first.
- A GroundControl Indicator; when the amber light is On, GroundControl is On (default)
  Meaning that on the ground, with nozzle at 90 degrees, groundspeed is forced to 0.
  See "Limitations"

The _Function gauge:
The VTOL function becomes active only when the nozzle is rotated 90 degrees (full flaps).
- RUDDER axis changes Heading.
  Note that you can use either rudder pedals / sticktwist rudder, or keys/buttons
  assigned to the FSX rudder functions.
- AILERON axis changes Roll speed (+/- 20 deg), and therefore lateral-speed.
- ELEVATOR axis changes Pitch speed (+/- 20 deg), and therefore longitudinal airspeed.
- FLAPS also controls nozzle (0, 20, 40 and 90 deg.)
  20 and 40 deg. is used for STOL operation, 90 for VTOL/Hover.
- THROTTLE axis changes thrust, and therefore longitudinal speed and altitude; 
  both proportionally to Weight and N1.

Hence, you can hover with ANY airspeed between 60 knots forward and backward, 
depending on pitch attitude.
Also note, that if thrust is not directed exactly downward (so pitch is unequal
to 0) you obviously need more thrust (higher N1) to maintain the same altitude.
Again, this effect is proportional; to the extent that even at full thrust you
may not be able to maintain altitude anymore (if the aircraft is heavy enough).

VTOL takeoff N1: (nozzle 90 deg)
- 26000 lbs (empty fuel weight): 75%
- 33000 lbs (max. safe VTOL weight): 94%
DO NOT attempt to takeoff when the Overweight Indicator is ON; the aircraft may still
takeoff vertically (with little overweight, full thrust and very low V/S), but you
will have little margin to be able to gain or even hold altitude. 




IMPORTANT NOTES AND LIMITATIONS
===============================
1. As outlined above (because this is an addon) I have to work within what's
   possible for an existing model; like: visible nozzle animations are usually
   coupled in the model to Flaps, and not an contiguous axis of its own (although
   of course that would require a seperate "nozzle" hardware controller axis as 
   well); Hence the limitation of discrete nozzle settings, since FSX only
   provides for max. 10 flap positions.
2. Make sure that your external control devices (joystick/pedals) are well-calibrated.
3. When VTOL-control is Active:
   - FSX gets a bit confused with its Stall warnings.
   - The IAS reading of your normal speed meter may not be accurate.
     It displays the IAS calculated by FSX, NOT the real IAS.
     Moreover, FSX cannot indicate negative speed (when going backward)
   - Although the Elevator, Rudder and Ailerons function are now controlling other
     functions (the ReactionControlSystem), the aircraft rudder, nosewheel, elevator
     and ailerons visual animations still work. Just ignore them :-)
4. VTOL on moving surfaces (like moving carriers).
   Unfortunately, FSX doesn't provide the handles to do proper speed control when the
   aircraft sits on a moving surface, caused by the fact that in FSX "groundspeed"
   is relative to the earth's surface, and NOT to the moving surface (e.g. carrier deck).
   See also "Operation tip 6: VTOL on moving carriers"
5. If you fly with CrashDetection On:
   Always touchdown gently ! If your descent rate is too high, the aircraft may crash
   or just have a damaged gear. The latter causes a crash on the next touchdown in that
   flight (the aircraft sinks into the ground). 


(V)(S)TOL operation tips
========================
1. Vertical Takeoff
- Make sure you are not too heavy; reduce fuel if necessary.
  Note that the max. safe VTOL weight is about 33000 lbs.
  IF TOO HEAVY, THE AIRCRAFT WON'T LIFT OFF !
- Taxi your aircraft to the Takeoff position.
- Set nozzle to 90 deg., using default keys F6/F7 or mouseclicking the flaps/nozzles
  position bitmap. The red Overweight indicator in the Control gauge should be Off.
- Apply full throttle,
  When N1 becomes > 75-94% (depending on weight), the aircraft will lift off.
- When you reach sufficient height, gradually move the nozzles and flaps to normal
  position, using "flaps-decrement" (default key: F6, or by clicking the gauge).
- And if your are lazy :-) : set "flaps-up" immediately (default key: F5).
  The aircraft now will accelerate quickly to 180 knots, after which VTOL-control
  deactivates and you can fly the aircraft as usual.
- When you change the nozzle out of the 90-degrees position, the gear is automatically raised.
- IMPORTANT: make sure the Wings are unfolded when you takeoff. Although it's possible
  to take of vertically with the wings folded (because the wings don't generate any
  lift at very low airspeed), the YAK will immediately fall out of the sky if you
  go into cruise flight.
  
2. Short Takeoff.
- Taxi your aircraft to the Takeoff position.
- Set flaps to Flaps 50, Nozzle 40 degrees.
- Apply full throttle and release the brakes.
- At around 70 knots, the aircraft will lift off.
- Raise the gear.
- Gradually move nozzles and flaps to the normal flight position.

3. Vertical Landing.
- Make sure you are not too heavy (see "Vertical Takeoff").
- Descent, slow down and gradually lower Flaps.
- Around 170 knots and 1/2 a mile before landing spot, rotate nozzles to 90
  deg and throttle up.
  The airspeed will gradually reduce to 0.
- Lower the gear.
- Hover the aircraft to the landing spot, using throttle, stick and rudder.
  When near the landing spot, preferably turn the aircraft straight into to
  the wind and descent slowly (with zero groundspeed) untill touchdown.
  See also "5. Hover"
- Set brakes, throttle to idle, and flaps/nozzles to 0.
- Release brakes and taxi to the parking spot.

4. Short Landing.
- Descent, slow down and gradually lower Flaps to 40 deg.
  Make sure you are lined up with the runway.
- Around 140 knots and 1/2 a mile before landing spot, rotate nozzle to 20 or 40.
- Lower the gear.
- After touchdown, apply brakes, set flaps/nozzles to 0 and taxi.

5. Hover.
During a hover (nozzle 90 degrees), you can change direction, longitudinal/lateral
speed and altitude using your controls. See section "Detailed functionality"
So longitudinal and lateral groundspeed is also dependant on windspeed/direction.
To hover or land with zero groundspeed in all directions: compensate headwind with
Elevator (Pitch), and Ailerons (bank/roll) for sidewind.

6. VTOL on moving carriers.
Also quite spectacular is VTOL operation on a moving carrier.
There's one catch though: you MUST switch OFF VTOL Ground Control.
As explained in the "Limitations".
A good place to start is:
- In FSX, select Mission "Tutorial 11: Helicopter Maneuvers 1" and check the box
  "Enable changes in selected mission" and "Show saved missions"
- Select your VTOL-capable aircraft instead of the helicopter.
- Set Ground Control OFF (click the amber light on the VTOL display gauge), and take off.
- Either follow the mission objectives (nice as well !!) or fly straight to the carrier.
- Approach the carrier (that moves with appr. 25 knots), using flaps, pitch and roll
  to control longitudinal and lateral airspeed, and land .....


Credits, Copyrights and Disclaimer
=================================
This package is freeware, and is available for your personal use.
Without my explicite permission, it may NOT be sold, modified, re-distributed, 
re-bundled and/or uploaded to another website or bulletin board in ANY shape or form.
And obviously, installing & using this package is at your own risk. 

Thanks to:
- Doug Dawson, for his great "XML2IPC" gauge, which allows me to interface from my
  XML code to FSUIPC.
- Peter Dowson, for creating/maintaining FSUIPC.
- Hadi Tahir for his model of the YAK-141.


Enjoy ......

Rob Barendregt, The Netherlands
Email: rc.barendregt@planet.nl



*******************************  End of README  *******************************
 