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VSKYLABS CTLS - Pilot Operating Handbook (POH)

VSKYLABS Test-Pilot: Flight Design CTLS Pilot’s Operating Handbook
FOR INFORMATION ONLY - FLIGHT SIMULATION USE ONLY DO NOT USE FOR REAL FLIGHT

VSKYLABS ‘Test-Pilot’: Flight Design CTLS
MANUAL / POH


The VSKYLABS Flight Design CTLS Project was developed for X-Plane 12 with the acknowledgement of 'Flight Design GmbH' company. However it is an independent project which is not affiliated and/or endorsed with/by Flight Design.
VSKYLABS Aerospace Simulations / Copyright Ⓒ2025 JetManHuss - VSKYLABS. All rights reserved. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the publisher, except in the case of brief quotations embodied in critical reviews and certain other noncommercial uses permitted by copyright law. For permission requests, write to the publisher, addressed “Attention: Permissions Coordinator,” at the following address: contact@vskylabs.com
Introduction

The VSKYLABS Test-Pilot: Flight Design CTLS Project for X-Plane 12 was designed to be operated in the simulation with the real CTLS-LSA aircraft operating instructions as a reference.

There are various CTLS variants existing in the world, featuring minor differences, upgrades and other nuances. These variants were evolved during the years 2008-2018, as a result of continuous development and improvements of the aircraft.

It is highly recommended to visit the following websites, as they are the best resources existing for the CTLS aircraft:

Note: VSKYLABS is not affiliated and/or endorsed with/by any entity and website. The following links are placed here for information only and VSKYLABS is not responsible for its contents.

Flight Design company website: https://flightdesign.com/ctls/
Flight Design USA website: http://flightdesignusa.com/aircraft/ctls/

The latter website features useful documents for CTLS pilots, including 'Syllabus for Transition to a Flight Design CTLS Light Sport Airplane', 'Aircraft Operating Instructions' and more. These may be used as a reference for operating the VSKYLABS CTLS aircraft in X-Plane 12 flight simulator.

Warning - For use with flight simulation only:
This Manual-supplement is not replacing in any way the real CTLS aircraft manual. However, it is presented here as the instruction manual of the VSKYLABS Test-Pilot: Flight Design CTLS virtual simulation model and should NEVER be used as a reference for real flight operations.

The real CTLS vs the VSKYLABS CTLS:


The VSKYLABS CTLS simulation was developed to follow the real CTLS handling and performance characteristics. It is a robust simulation model which is making use of X-Plane 12 sophisticated flight dynamics and physics simulation, extracting it to its limits. As a result, the VSKYLABS CTLS simulation is demonstrating highly accurate and authentic flight dynamics characteristics. However, the VSKYLABS CTLS simulation model is being constructed within the X-Plane’s flight dynamics limitations. Systems algorithms may also differ from the real CTLS in certain aspects.

Simulated systems:
The VSKYLABS CTLS is making use of X-Plane 12 latest native features, systems and physics, with no dependencies on additional/external plugins or software. This is assuring a high airworthiness condition in X-Plane, throughout its update process.

Additional Notes:
The VSKYLABS CTLS project is under constant development and evaluation. Differences from the simulated VSKYLABS CTLS aircraft and the real CTLS aircraft may be noticeable:
  • G1000 Variant: The VSL CTLS (G1000) variant features LR built-in G1000 nav and autopilot system.
  • Analog variant avionics package: The VSL CTLS (analog) is equipped with basic cockpit panel and avionics, based on X-Plane's GNS530 and simplified EFIS display.
  • HS34+AP74 (analog variant): These are not in-depth simulated...only modeled with simplified/basic functionality, allowing autopilot operation.
Pilot and passenger 1st person view visualization:

The VSKYLABS Flight Design CTLS v5.0+ includes an animated 3-d pilot figure, as well as a highly detailed 3-d passenger.

The passenger will be visualized when it is set with a weight of ~50 kgs or more.

Both the 3-d pilot and the passenger can be hidden with the use of the ‘Hide-Yoke’ feature in X-Plane (pressing ‘y’) or by a designated button/key assignment (for ‘hide yoke’, or via the VSL CTLS assignments).

Complementary systems - AOA indicator:

The VSKYLABS CTLS includes an additional virtual AOA (Angle of Attack) avionics upgrade, based on the 'Alpha Systems AOA' Eagle AOA kit.


Development notice:
Development of the VSKYLABS replica-virtual AOA indicators following the 'Alpha Systems AOA' design was approved by 'Alpha Systems AOA', however it is an independent development effort, which is not affiliated with 'Alpha Systems AOA'.

For thorough information you are welcome to visit their website at: https://www.alphasystemsaoa.com/

AOA indicator features:
The Eagle AOA kit is a highly visible, full color chevron style display. When you come in for a landing you want to fly to the blue donut (on speed for landing). Should you come in with too low of an angle of attack, the yellow chevron will light up and tell you to put your nose up. Should you come in with too high of an angle of attack, the red chevron will light up and tell you nose down.

Real-world Eagle vs VSKYLABS Eagle indicator:
The VSKYLABS implementation of the Alpha Systems AOA 'Eagle' replica is focused at this stage in AOA indication. It does NOT include the peripheral/complementary systems and options such as calibration, diagnostics, optional aural alerts and other components. The included AOA indicator was calibrated 'in-house' at VSKYLABS, as part of the overall tuneups of the flight dynamics model.

Angle of attack indicator - additional info:
The following brief instructions of the VSKYLABS 'Eagle' replica is brought here for use with the virtual VSKYLABS aircraft, in X-Plane. Although the indication methodology, color and shape replicates the real-world device, it is not meant to be used as a tutorial that replaces the actual Alpha Systems AOA 'Eagle' operations manual. For real-world instructions please visit Alpha Systems AOA website: https://www.alphasystemsaoa.com/

The Indicator:
Note: Display shown with all segments illuminated for illustration.


Green Bar: It is indicating high amounts of lift, lower angle of attack. The angle of attack is relatively low with lots of surplus lift.

Green Bar + Yellow Triangle: Va (MAA), operations allowing full deflection of flight controls.

Yellow Colored Segments: It is indicating caution; the angle of attack is relatively high. If not intentional, take action to reduce the angle of attack.

Complete Blue Doughnut: It is defining the segment that identifies Optimum Alpha Angle (OAA) or 1.3Vs, 30% margin away from stall (see definition). The system can illuminate both, just the top or just the bottom arcs to give a display just above or just below the set point.

Red Colored Segments means the angle of attack is too high. Take immediate action to reduce the angle of attack such as performing a stall recovery procedure. You are in dire straits.

Interactions and Special Joystick/Key assignments:

The VSL CTLS uses various X-Plane features to cover some of its systems and other features. PLEASE READ the following instructions carefully, so that you will be able to set up and fly the CTLS without issues.

From version v5.0, the project includes the VSKYLABS ‘Cockpit-Builders Heaven’ layer, which allows assigning all aircraft switches, knobs, levers, and interactions in a designated, uncluttered section in the X-Plane 12 assignment screen.To use it for key/button assignments, simply type ‘ctls’ in the search bar and select your assignment. Here is a sample screenshot:

The Flight Design CTLS General Information

The CTLS aircraft is produced by Flight Design of Germany. Produced in 2008, it is a part of Flight Design CT series family. It is a high-wing, tricycle, two seat light sport aircraft. The aircraft is built mainly from composite materials construction, having an efficient aerodynamics shape and relatively low weight, allowing it to carry high useful loads. It is powered by a Rotax 912 ULS engine.

Thanks to its design efficiency, the CTLS is fast, spacious and capable for cross country flights, with a cruise speed of approximately 112 knots, and maximum range of up to 850 nautical miles. Due to its cantilever wing design, the CTLS has no wing struts to obstruct the outside view. Main landing gears are composite constructed as well, designed to absorb hard landings. The CTLS is equipped with a BRS (Ballistic Recovery System) parachute.
The VSKYLABS Test-Pilot: CTLS - Quick Guide

Engine and Propeller:
  • The CTLS is powered by the Rotax 912ULS (Carburated, 100 rated BHP @ 5800 RPM) engine.
  • Propeller gear reduction of 2.43:1
  • The VSKYLABS CTLS is modeled and tuned with the Neuform CR3-65-47-101.6, 3 blade, composite propeller. It has a fixed pitch.
Aircraft Equipment - 'Classic CT analog' cockpit panel:
  • Analog Instruments panel - left section:
    • Analog Airspeed indicators.
    • Analog Altimeter.
    • Artificial Horizon.
    • Analog Vertical Speed Indicator.
  • Analog Instruments panel - center section:
    • Carburetor heat push/pull handle.
    • Cabin heat push/pull handle.
    • X-Plane GNS-530 (including a GPS, COM, NAV).
    • Transponder (GTX-327 'simplified').
    • Magnetic compass (overhead).
  • Analog Instruments panel - right section:
    • Analog Engine RPM indicator.
    • Analog CHT indicator.
    • Analog Voltmeter indicator.
    • Analog Oil temperature indicator.
    • Analog Oil pressure indicator.
    • Alternator indicator light.
    • Analog HOBBS.
    • CB's panel.
  • Complementary Avionics enhancements:
    • HS34 'Dynon type' (simplified) panel.
    • Notepad EFIS - PFD.
    • AP74 'Dynon type' (simplified) autopilot panel.
  • AviTab ready for 'Plug and Play':
    • The AviTab is optional, and could be removed/placed by clicking/touching at the mount base (the semi-transparent suction cup).
    • The AviTab is a VR-compatible tablet display, featuring a moving map, PDF viewer, airport info, and Navigraph integration. It is a highly recommended, FREEWARE plugin, which is NOT a part and NOT included in the VSKYLABS project/s. However...the included compatibility layer allows to use it on-the-fly by simply installing the plugin on X-Plane. It is compatible with Windows, Linux and Mac.
    • Plugin's page at the X-Plane.org can be found here: https://forums.x-plane.org/index.php?/files/file/44825-avitab-vr-compatible-tablet-with-pdf-viewer-moving-maps-and-more/
  • Aircraft Equipment - 'G1000 CT' cockpit panel, additional:
    • Fully featured LR G1000 bundle.
    • GNS530 (biased to com2/nav2).
    • Analog IAS and engine RPM gauges.
  • Both aircraft equipment:
    • Ballistic Recovery System.
    • External lighting: Anti-collision, navigation and landing lights.
Aircraft Limitations

Airspeed limitations:

Stall speed
  • Flaps -6.................44 Kts CAS
  • Flaps 0..................42 Kts CAS
  • Flaps 35................39 Kts CAS
Maximum flaps extended speeds (Vfe):
  • Flaps 0...............100 Kts CAS
  • Flaps 15.............80 Kts CAS
  • Flaps 35.............63 Kts CAS
Never exceed speed (Vne)............. 145 Kts CAS
Maximum speed in rough air..........138 Kts CAS

Maximum (demonstrated) cross-wind.:
  • Flaps 0 .............16 Kts
  • Flaps 35............11 Kts
Flight loads limitations:
  • Maximum flight load factor.....+4g / -2g
Engine limitations:
  • Max takeoff power...............100 HP @ 5800 RPM (max 5 minutes).
  • Max continuous power.......95 HP $ 5500 RPM
  • Minimum takeoff engine speed.......4800 RPM
  • Idle engine speed................................1500 RPM approximately
  • CHT temperature.................................248 Deg F
  • Min. Oil temperature............................120 Deg F
  • Max. Oil temperature............................248 Deg F
  • Recommended Oil operating temp….. 190-230 Deg F
  • Oil pressure - normal............................29-73 PSI
  • Oil pressure - minimum........................12 PSI
  • Fuel tank capacity....2 wing tanks with 17 gallons each (34 gals total)
Other limitations:
  • Aircraft is not certified for aerobatics; Turns steeper than 60 degrees bank are prohibited.
  • Aircraft should be operated in day or night, VFR conditions.
  • IMC flight is prohibited.
  • Flying in icing conditions is prohibited.
  • Flight operations are not recommended in windy/gusty conditions (above 25 knots).
Aircraft Handling Characteristics

Stalls:
  • Stall characteristics in level flight are docile. Recovery to normal flight is made by releasing/pushing the stick forward, increasing speed and pulling the aircraft gently to level flight.
  • Loss of altitude during stall and recovery is approximately 165 feet, with mild pitch down tendency (up to ~20 degrees).
Spins:
  • The CTLS is not demonstrating a tendency to get into an inadvertent spin during stalls (level and during turns). However, if the aircraft is spinning, set all control surfaces to neutral position, set the rudder opposite to spin's direction, reduce engine power and recover smoothly.
Flaps:
  • In general, the CTLS can land with all flaps positions. Stall speed with negative flaps position will be higher, resulting with a longer landing distance.
  • No flaps approach speeds (recommended):
    • Flaps 0.........54 Kts
    • Flaps -6.......64 Kts
Operations and Checklist supplement

General orientation and cockpit perspective:
Due to the CTLS tapered nose, the pilot's forward view is noticeably to the left side. This may cause confusion for choosing appropriate reference points down the runway. To set yourself with the appropriate forward line of sight, try to "draw" a vertical line which starts between the rudder pedals and goes straight up.

Engine start:
  • The fuel shutoff valve is blocking the access to the starter switch.
  • Before starting, make sure that the valve is opened completely (all the way up).
  • Pull the choke out (all the way) and keep it open for approximately 20-30 seconds after the engine is running, then close it down.
  • When starting the engine, make sure that the throttle is not opened for more than 10%. Right after start, set engine RPM to 2000-2500 RPM.
  • Engine RPM may be increased only after the oil pressure exceeds 28 psi (could take a while, 10-30 seconds).
  • Engine warm up is recommended. Set it to 2000 RPM for 2 minutes. The engine will be ready for operation when oil pressure will exceed 122 degrees F.
Takeoff and climb:
  • On short runway takeoff, flaps are set to 15.
  • On paved runways, takeoff is more efficient with flaps set to 0.
  • During takeoff run, engine RPM should exceed 4800. Lower RPM is an indication of insufficient available take-off power.
  • When the acceleration is noticed, pull the stick gently to reduce nose-wheel loads.
  • When airborne, release the stick pressure gently and let the best-rate-of-climb speed to build-up (67 Kts with flaps 15 / 72 Kts with flaps 0). Note that these are for takeoff weight of 1320 lbs.
  • Once reaching a safe altitude of at least 150 feet AGL, flaps may be adjusted inflight. It is recommended to climb with the flaps set to 0 degrees. Once the airspeed reaches 67 Kts on climb, flaps may be retracted from 15 to 0 degrees inflight.
  • When reaching a climbing speed of 73 Kts, flaps can be retracted to -6 degrees. Stabilized, efficient climb speed with this flaps position is 78 Kts.
  • Warning: drag and lift coefficient are being reduced when flaps are transitioning from 0 to negative value -6. This may cause a slight drop in climb rate, and when done in straight and level flight, will induce a slight sink rate. Do not retract the flaps to the negative position when flying close to the ground.
Cruise:
  • Cruise flight should be with the flaps set to -6. This flaps position is resulting with the lowest drag. When the flaps are set to -6 degrees, aircraft prompt acceleration will be noticed.
  • Propeller design (pitch adjust) is set so that max continuous power (5500 RPM) will not exceed during horizontal flight with full throttle. However, always monitor your RPM as it is highly affected by temperature, air density and current flying speed.
  • For efficient cruise, set RPM to 4800. Higher RPM will result with higher airspeed but higher fuel consumption as well.
  • Monitor fuel quantity during flight by observing the fuel tank indicators inside the cockpit (located at each wing root). Keep in mind that correct fuel quantity reading should be made only when the wings are leveled.
Maneuvers:
  • Change your flight heading with aileron and rudder coordination.
  • Maximum allowed airspeed (Vne) is derived from the BRS system operational envelope, and should not be exceeded.
  • Turns with more than 30 degrees of bank should not be flown below 54 Kts.
Stalls:
  • Approaching a stall is indicated by sluggish controls as the aircraft is getting closer to the stall speed. During the stall, ailerons effectiveness is reduced and control may be obtained with the use of rudder and horizontal stabilizer.
Gliding performance:
  • Gliding angle should be assumed to be 8.5 to 1 (no flaps).
  • Flaps extension will reduce sink rate, but will result with a lower speed and will shorten the gliding distance.
  • Speeds for best gliding performance:
    • 1320 lbs..........78 kts
    • 1100 lbs..........69 kts
    • 880 lbs............64 kts
Approach and landing:
  • Always try to land into the wind.
  • Maintain a stable, straight line final approach.
  • Steep approaches with flaps setting changes on short final may result in dynamic, unstable flight conditions.
  • Maintain low power during the approach (10-20% above idle). It will give you a good feel for proper engine operation.
  • Carburetor heat should be activated if there is a risk for carburetor icing. However, make sure that it is pushed (off) before landing, so that full engine power will be available when needed (in case of a go-around situation etc...).
  • About a meter high above the runway (~3 feet), idle the throttle and flare the aircraft to a smooth landing.
  • The CTLS can be landed safely with the flaps at 15 degrees, 0 degrees and even -6. However, maximum flaps deployment (35) should be used preferably when landing on a very short runway, and with low cross-wind conditions. The increased flaps deflection increases drag, resulting in a loss of airspeed during the flare, and sluggish controls.
Engine shutdown:
  • During the descent and approach, the engine is being cooled enough, and may be shut down by switching off the ignition.Switch off all electrical equipment (including the alternator) prior to engine shutdown.
Performance supplement

Performance figures for MTOW (1320 lbs):

Takeoff roll:
Flaps 15.........................820 ft

Takeoff distance (to 50 ft):
Flaps 15......................1500 ft

Takeoff speed:
Flaps 15......................47 Kcas
Flaps 0.........................54 Kcas

Best rate of climb:
Flaps 15.....................62 Kcas............740 ft/min
Flaps 0........................73 Kcas...........800 ft/min
Flaps -6......................78 Kcas............770 ft/min

Best angle-of-climb:
Flaps 15.....................61 Kcas
Flaps 0........................66 Kcas

Maximum level speed:
Flaps -6......................120 Kcas @ 5500 RPM

Maximum range:
830 Nautical Miles......97 Kcas.....flaps -6.......4300 RPM

Speeds for best gliding performance:
1320 lbs..........78 kts
1100 lbs..........69 kts
880 lbs............64 kts.
Airplane and systems

Airframe:
  • The CTLS is a conventional high wing aircraft.
  • The aircraft features an all-moving horizontal stabilizer. An electrical trim is set to activate a trim tab.
  • The CTLS airframe is made of composite materials, resulting in good aerodynamics and low structural weight.
Engine:
  • Powered by Rotax 912 ULS.
  • Propeller integrated gearbox (with reduction of 2.43:1).
  • Constant pressure carburetor.
  • Electric starter.
  • Air is fed into the engine through a NACA air inlet located on the right side of the cowling, flowing the air into an air filter expanding chamber.
  • When carburetor heat is activated, airflow into the air chamber is switched from outside airflow to heated air.
Propeller:
  • The CTLS may be fitted with various propeller types. The VSKYLABS CTLS simulation model is fitted with a simulated Neuform CR3-65-47-101.6 3 blade, composite propeller.
  • The propeller is set to prevent over-speeding of the engine during takeoff, climb and level flight, at full power.
  • Full static engine RPM on the ground should be approximately 4800-4900 RPM. Higher RPM (5500 and above) will be reached during level flight and full throttle.
Fuel system:
  • Each wing is fitted with a 17 gal (65 liter) fuel tank.
  • Fuel is filled into the tanks via the fuel tanks openings on the front, upper side of each wing.
  • Fuel is fed by gravity from the tanks into a gascolator, and the engine-driven, integrated fuel pump feeds the fuel from the gascolator into the engine.
Electrical system:
  • Based on a 12V 7 Ah lead-gel battery, being charged by a DC alternator which is integrated into the engine.
Landing gears, brakes:
  • Main landing gear is a composite, cantilever spring type construction.
  • The main wheels are equipped with a hydraulic brakes system, activated by a lever inside the cockpit. There is no differential braking in the CTLS.
  • The brakes can be locked by blocking the return line, functioning as a sort of a parking brake. The return line valve switch is located just behind the throttle quadrant in the cockpit.
  • The nose wheel is steerable by the use of control rods which are connected to the pedals.
Flight controls:
  • The CTLS features dual controls, allowing full operations from both seats.
  • The trim is mechanical. Trim wheels and indicators are located on the center-lower-tunnel (which goes all the way to the back section of the cockpit).
  • The ailerons are featuring a coupling mixer with the flaps, and the ailerons are being deflected as well as the flaps are set.
Ballistic recovery system:
  • The CTLS features a ballistic recovery system.
  • The system includes a recovery parachute and a ballistic rocket which are located behind the main bulkhead. The rocket is activated via a pull cable, which is attached to the deployment handle in the rear section of the cockpit tunnel, between the seats.
Panel and systems

Cockpit - instrument panel:
  • The CTLS instrument panel is available in various layouts.
  • The VSKYLABS CTLS is equipped with the 'Classic VFR' panel, which could be enhanced to include EFIS/PFD + Autopilot.
  • Cockpit panel - BASIC (classic) layout:
  • Cockpit panel - Enhanced layout:
  • Cockpit panel - upper section:
  • Cockpit panel - lower panel:
  • Cockpit panel - mid-section (tunnel):
VR Operations in X-Plane 12

The VSKYLABS CTLS was designed for VR operations in X-Plane 12. It is of course optimized for 2D usage as well.

All relevant cockpit switches, knobs, levers, handles etc...are fully operational with the use of mouse manipulators or VR touch controllers.

Here is a straightforward description of complementary manipulators in the CTLS cockpit environment. Please use the screenshot below as a reference:

  1. Doors open/close - by using each door open/close/lock handle. When the doors are opened, the upper surface of each door is also serving as an activation touch zone. This is making the operation more comfortable as you don't have to reach out too far or use the laser/pointer.
  2. BRS safety pin - when removed from the BRS operation handle, it will be placed, automatically in the right door placement. To secure the BRS system, use this touch zone, and the pin will be placed back into the BRS handle (securing back the system).
  3. EFIS/AP toggle - Default cockpit configuration is featuring a complementary notepad based EFIS display, along with the HS-34 and AP-74 panels. To switch this configuration back to the classic analog layout, simply click on the EFIS Notepad. To get it back, use the airspeed indicator glass as your touch zone.
  4. Sun Visors - Each sun visor can be folded/unfolded by using its respective touch zone.
  5. AviTab - The Avitab and its mount are visible by default, awaiting for the AviTab plugin to be installed in X-Plane. Clicking on the AviTab suction cup base will hide/show the Avitab and its holder. Note: the AviTab plugin is not included in the VSKYLABS CTLS aircraft, and it is not related with VSKYLABS in any ways. It is a free plugin which is available at the X-Plane.org website. For more information please visit: https://forums.x-plane.org/index.php?/files/file/44825-avitab-vr-compatible-tablet-with-pdf-viewer-moving-maps-and-more/