Monday, October 5, 2015


Ducted-Fan Powered Sport Plane Prototype.
A concept lightweight "cold jet" airplane.

This prototype is based on a research report, from the 24th International Congress of the Aeronautical Sciences.
The report is available for reading in this link to the PDF document:

General Information:
The VSKYLABS DFSP-39-A is a full-composite, light aircraft with maximum take-off weight of 2000 pounds. It's propulsion unit utilizes a 700 horse power piston engine, and a composite fan driven by a light aluminum alloy. A by-pass cooling duct for the engine radiators is part of it's inlet channel and nozzle design. It is different from the VSKYLABS Ultra Light DFSP-39 aircraft. It is heavier, larger and designed for cruise speeds of 200 knots. 

The successful realization of a ducted fan propelled aircraft is difficult. Many designs failed because of problems with fan efficiency and shorter life time due to vibrations induced by the flow distortion at the inlet section of the fan. There are also other problems, such as the aerodynamics of the inlet channel, complex design of the fan and its drive, the piston engine installation and it’s cooling and more. In a case of engine failure, additional drag caused by the choked inlet.

Modern ducted-fan propulsion unit designs utilize a gas turbine engine, known well as the Turbo-Fan engine, which is actually a ducted fan unit, driven by a small turbo-jet engine. The Turbo-Fan engine has a lot of advantages over the piston driven ducted fan unit. I'll discuss this issue on a different post.

The aircraft is not for the beginner pilot; It is under powered, sensitive to power changes, agile but violent when you exceed it's flight envelope limits. It's a true challenge to fly, and a good demonstrator for this concept and it's limits.

VSKYLABS DFSP-39-A specifications:
Type: Single seat lightweight Ducted Fan powered sport aircraft.
Powerplant: One 700HP reciprocating engine which drives 7 blades fan unit.
Wingspan: 20 feet
Length: 28 feet
Weight: empty - 1400 lbs, full - 1900 lbs
Flight ceiling: not available yet - project and plane under development. 
Internal fuel: 400 lbs
SFC: not available yet - project and plane under development.
Range of operation: not available yet - project and plane under development.
Cruise speed: 165 knots
Maximum speed: 250 knots
Stall speed: 80 knots

Flying tips for the DFSP-39-A on X-Plane:

In general:
The DFSP-39-A is small and light aircraft. Controls are sensitive but it's behavior is docile and very predictable. It looks like a fast and aerobatic Jet, but it isn't. It is a light plane that's flying "on it's wings". The DFSP-39-A is under powered. Mild vertical aerobatic maneuvers can be achieved by flying the plane above 180 knots.
The 700HP engine's torque affects the light aircraft very much. Use aileron trim in all phases of flight, since roll moments will be noticed on engine power setting changes.

Speed management: 
Acceleration is moderate. You will notice this fact upon take off, and whenever trying to reach it's fast-cruise speed (above 200 knots). Climb at 150-160 knots, make room for slowdown since this aircraft does not feature speed brakes.

Take off and landing: 
Apply full power, nose up at 90 knots, lift off at 100 knots. Lift off below 100 knots is dangerous due to severe roll moments.
Landing the plane is tricky because the aircraft is energetic and light, so you'll have to practically fly the touchdown at 90 knots. Remember not to fly the aircraft below 90 knots due to severe high-alpha stall characteristics.

Sunday, September 20, 2015

VSKYLABS 'Little Lightning'

VSKYLABS 'Little-Lightning' aircraft add-on for X-Plane 10.36+

Special Low-Cost add-on

Buy now

What can I say?:
It's a 'Little Lightning' !
A beautiful classic piece of an aircraft !

This classic aircraft is a light-and-small JetManHuss - version of the legendary P-38 Lightning. It's fresh and streamlined design, built to match the performance of an ultralight aircraft with good flight handling characteristics. With it's large wingspan, new fuselage and cockpit design, fixed, streamlined landing gears and advanced GPS on board, this little lightning will take you to the skies with a real style :)

General specification:
Crew: one pilot.
Weight: 645 lbs empty / 1028 lbs fully loaded.
Wing span: 22 feet.
Length: 22 feet.
Engines: two counter-rotating, 74HP reciprocating engines.
Maximum speed: ~170 knots.
Stall speed: ~50 knots.

Project features:
  • High detailed 3D model, glares in the sun (also the scratched, bubble canopy).
  • Fully animated.
  • 3D cockpit (with lights for a romantic night flying).
  • Amazing sounds.
  • Cool textures.
  • Free future updates.

Flying tips:
  • This little lighting will start rolling forward on idle, without brakes. You can taxi the plane on a single engine for a more comfortable ride.
  • Flaps are very effective. Pay attention to pitch trim, to avoid a nose-down moment on flaps retraction.
  • On a single engine, the little lightning needs attention and care. Always turn towards the LIVE engine, use the rudder trip knob and keep your speed up.
  • Have Fun !!!

Please read the COPYRIGHT and DISCLAIMER information which can be found at and also within the package archive.

Friday, September 11, 2015


VSKYLABS Pulse Jet Concept Prototype 'Firefly'
Original Design Valveless Pulse Jet Powered concept  aircraft

NEW UPDATE (11.9.2015)
(a free download link was sent to all the former Firefly buyers)

This package contains TWO aircraft:
- 'Firefly-1'
- 'Firefly Delta dart'
  • The 'Firefly-1' is updated with authentic Pulse jet engine sounds.
  • The 'Firefly Delta Dart' is a new version of the Firefly, utilizing a double-delta wing layout and ferry fuel drop-tanks.

Scroll down to read important and useful information

Valveless Pulse jet engine demonstration
(from YouTube):

VSKYLABS 'Firefly 1' + 'Firefly Delta Dart' prototypes features and characteristics:

I have updated the 'Firefly 1' Pulse Jet aircraft. The original version suffered from some stability issues, as for being a tailless aircraft. It's vertical wing tips/stabilizers and small rudders limited it's cross-wind performance and reduced it's lateral stability qualities, and it's high aspect-ratio, tailless wing layout limited it's weight and balance and center of gravity aspects, as it narrowed it's flight envelope and it's flexibility.

When I first started it's design refurbish, I was planning to enlarge the vertical stabilizers/rudders, and to add a tail or canards for more comfortable longitudinal control. I didn't want to divert the design into an obvious design (which will look like a traditional glider, and will perform perfectly with the low-thrust pulse jet propulsion). So...I've decided to go with the delta wing design, which could be perfect for expanding the 'Firefly 1' flight envelope and it's optional payload (just like the F-16XL aircraft). Although the 'Firefly Delta Dart' is a low sub-sonic aircraft, the Delta wing layout offers some good advantages for it's low-speed performance. (I will write about it soon in this page).

This Update includes:
  • Two different aircraft inside.
  • A new version of the 'firefly 1' - the 'Firefly Delta Dart'.
  • Authentic pulse jet sounds update for both 'Firefly 1' and 'Firefly Delta Dart'.

Here are some general details regarding the 'Firefly' prototypes:

General flying tips for the 'Firefly Delta Dart':

  • The aircraft is setup in a way which will let you get it out of control, if you fly it out of it's comfort zone. It's an experimental aircraft and this is all the fun! :)
  • You can select to unload the ferry drop tanks from X-Plane's Aircraft/weight and balance window. Without these fuel tanks, the aircraft will be much more energetic, and you'll have to give attention to high angle of attack operations.
  • High angle of attack (Alpha) warning alert will sound as you will get close to it's limit. ease on the stick when you hear it. You are close to a pitch-up situation.
  • Rotation speed with the ferry drop tanks is about 110 knots. Final landing speed ~130 knots. Touch down at ~ 110 knots. Without the ferry tanks you can reduce these speeds by ~15 knots.

('Firefly 1') Lightweight fuselage is based on common Sailplanes fuselage size and construction.

Internal fuel tank is located inside the fuselage, behind the cockpit and below the wing. Internal fuel capacity is up to 420 lbs.

Retractable landing gears are electrically operated and retracts into an aerodynamic portable tank. Wheel base is 4.60 feet. The portable tank is attached to the bottom of the fuselage and it is not droppable inflight. There is a strorage compartment in the tank for utility equipment and personal use. Battery for extraction/retraction is located inside the tank.

('Firefly 1') Main wing features leading edge slats and trailing edge elevons. Wing tips are equipped with rudder control. The FireFly is controlled by a fly-by-wire system that corporates artificial stabillity. The FireFly is flyable without artifical assitance. Leading edge slats are automatic operated and extended below 130 knots. 

('Firefly 1') Canard surfaces are positioned in front of the fuselage. The canard surfaces are a low aspect-ratio fixed wing planforms that increases the FireFly stability at all speeds and reduces pitch-trim forces. 

Twin valveless pulse jet engines are attached to the wing symmetrically close to the fuselage. Throttle control system is electronic and located inside the fuselage. The engine constructed without any moving parts and an integrated air-pressure system allows static startup and ignition, as well as in flight. The air-pressure system is located in a compartment in front of the cockpit and it's electrically operated.

Electrical power for the FireFly is supplied by two aviation batteries and a ram-air generator that is located on top of the wing. When airborne, the ram air generator produces power for avionics and flight control systems. There is a battery for ground operations and backup. Power for landing gear retraction is supplied by a separate battery that is located inside the portable landing gear tank. 

('Firefly Delta Dart') Two external ferry fuel tanks can be added (they are not drop tanks, but in X-Plane they can be dropped by using the "Drop all drop tanks" button), containing 200 lbs of usable fuel each. Complete flight can be executed with the external fuel tank attached and full. Sport and aerobatic flight is better done without the external ferry fuel tanks, or when it's empty.

General specifications:
Type: Single seat lightweight pulse jet powered sport jet aircraft.
Power plant: Two Lockwood-Hiller valveless pulse jet engines, producing 420 lbs of thrust (each) at sea level.
Wingspan: 25.8 feet
Length: 20.8 feet
Height: 8.9 feet
Weight: empty - 850 lbs, full - 1400 lbs
Flight ceiling: 24,000 feet
Internal fuel: 420 lbs
External fuel: Up to 400 lbs in two drop-tanks
SFC: 1.7/hr.
Range of operation: 250 - 400 miles (internal fuel only) / 500 - 800 miles (with external fuel tanks)
Cruise speed: 160 knots / 170 knots ('Firefly Delta Dart')
Maximum speed: 300 knots
Stall speed: 70 - 90 knots

Engine simulation:
X-Plane does not simulate Pulse jet engines. Pulse jet engines built without any moving parts, there are no turbines and compressors, so engine response to addition of fuel is immediate, similar to liquid fuel rocket engines. The Pulse jets engines of the 'Firefly' are simulated in X-Plane as a throttled rocket engines, with loss of thrust as they go up in the atmosphere. Above 20,000 feet, the simulated pulse jets produces about half of it's maximum thrust at sea level.

External fuel tanks:
External fuel tanks are not drop-tanks. It can be setup for sport flying without the external tanks via the weight and balance setup window in the simulation. It can be dropped in flight as drop-tanks using joystick button assignment via the joystick button setup window in the simulation.

The cockpit is located in the backseat of the FireFly. It is a glass cockpit type with 3 Multi Function Display screens. Controlling the aircraft is done with a conventional centered stick, rudder pedals and twin throttle lever on the left side.

The cockpit is divided to three: Front panel, Left panel and Right panel. 

Front panel layout:

Front panel includes (left to right): 
Artificial stability switch, Landing gears handle and mechanic indicator, Battery, Fuel and Ignition switches for engines startup and operations, Moving map display with multiple zoom and layers (switches are clickable around the MFD), Fuel meter, Chevron (angle of attack indicator for landing assist), Internal lights panel no.1 (on the wooden panel), Below it there is an artificial horizon, Indicated airspeed, altitude and compas digital display (center MFD), Avionics master switch, Right MFD for engine, fuel flow data and digital HSI. On the right there is the parking brake handle (yellow "T" handle). On the lower right side there is the warning lights panel.

Special features:
Quick Field Of View Setting: There is a yellow tab on the right, located on the glare-shield, signed:"FOV". Push this Tab for switching to recommended Field Of View setting for the FireFly. It is a clickable Tab that switches between 75 to 95 Degrees of lateral field of view.

Quick time of day setting: Left to the FOV tab there is a round button. Push and hold this button to change the time setting from day to night. It is cyclic.

Right Panel Layout:

Right panel includes (front to aft): 
Pitot heat and AOA heat switches, Garmin GPS, COM 1 panel, COM 2 panel, External and internal lights panel and NAV 1 panel. On the right side of the cockpit there is a quick RIGHT engine shut down red colored handle.

Left Panel Layout (front to aft):
Generator and inverter switches, Twin throttle lever and a quick LEFT engine shut down red colored handle.

Please read the COPYRIGHT and DISCLAIMER information which can be found at and also within the package archive.

Sunday, September 6, 2015

VSKYLABS 'Greyhound-2'

VSKYLABS "Greyhound - 2"


Original Design of a high performance two seat light Jet aircraft Prototype.
The Greyhound is a research prototype which designed for control and stability investigation of lightweight, high performance aircraft.

*** A free download link was sent to all former buyers of the VSKYLABS 'Greyhound' ***  

Project overview:
The VSKYLABS 'Greyhound - 2' is a high performance two seat light Jet aircraft, built around two General Electric J-85 engines (same as in the T-38 Talon).
The challenge of this project was to design an ultralight yet plausible, high performance aircraft, with a wide flight envelope and good stability characteristics.

6.9.2015 Update highlights:
The 'greyhound-2' prototype is more heavy, long and stable aircraft than the first 'greyhound' prototype. It's aerodynamic layout is improved and it's flight model was re-built, as well as the cockpit, which include now a 3D Heads-Up-Display, and some fixes such as adjustment buttons for the CDI needle. External and internal 3D models and textures are improved, with ambient occlusion and normal mapping. 

VSKYLABS 'Greyhound-2' general specs:
Empty weight: 5300 lbs
Maximum takeoff weight: 8600 lbs
Length: 30.5 feet (without the nose tube).
Wingspan: 22 feet.
Power plant: Two General Electric J-85 Turbojets engines, 3500 lbs of dry thrust, 5000 lbs with full afterburner.

How to fly the 'Greyhound-2':
It's a very light and powerful sport plane, not a Jet-fighter. Handle it with care.
Use the Air Brake on final when landing.
Leading edge Flaps are automatically extracted below 250 knots.
Most important: Have fun!!!

Please read the COPYRIGHT and DISCLAIMER information which can be found at and also within the package archive.

New introduction video and screenshots:

Thursday, August 27, 2015

VSKYLABS 'Little Rocket Racer'

VSKYLABS 'Little Rocket Racer' add-on for X-Plane 10.36+

Special Low-Cost add-on

What can I say?:
It's a Little Rocket Racer !!!
The Highest fun and thrill you can squeeze out of X-Plane flight simulator.

This magnificent aircraft is a light-and-small JetManHuss - version of the Legendary Sky Rocket. It's built around a single pilot, it's light, fast and a thrill to fly. It's not for beginners, but it will forgive the novice pilot with it's stability and ease of control, and will challenge the ace pilot with it's dare devil behavior when it's pushed down to it's limits.

One of my favorite creations of all times for sure!

General specifications:
Crew: one pilot.
Weight: 850 lbs empty / 1140 lbs fully loaded.
Wing span: 22.4 feet.
Length: 16 feet.
Engines: two counter-rotating, 125HP reciprocating engines.
Maximum speed: 190 knots.
Stall speed: ~60 knots.

Project features:
  • High detailed 3D model, glares in the sun (also the scratched, bubble canopy).
  • Fully animated.
  • 3D cockpit (with lights for a romantic night flying).
  • Amazing sounds.
  • Cool textures.
  • Free future updates.

Please read the COPYRIGHT and DISCLAIMER information which can be found at and also within the package archive.

Sunday, August 23, 2015

VSKYLABS 'Twin Racer 007'

VSKYLABS 'Twin-Racer 007' Full scale racing airplane Add-on for X-Plane 10.36+
(Based on the DH.88 Comet)

Special Low-Cost add-on:

This aircraft add-on was designed, built and tested by a retired professional real-life pilot (myself :)), which caught by this hobby of flying in the virtual world.


Recommended Field of View setup is 65 to 95 degrees

3D Cockpit is animated and straight forward, with all the needed instruments and 3D switches for fun-fly operations, including an 'F-O-V' button to change the field of view settings and a 'SERVICE' button to open the canopy and hatches. Two rheostats are located on top the from panel for instruments and flood lights.

This project features:

  • High quality, fully animated 3D design.
  • 3D cockpit with sun-glaring glass canopy.
  • Open the canopy and service hatches from the cockpit.
  • Realistic sounds.
  • Performance and handling are realistic (and simple).
  • Free future updates of this amazing, evolving airplane.

The aircraft is a good performer, with specifications and performance which are similar to the DH.88 Comet airplane.

Specifications of the 'Twin Racer' 007:
Crew: one
Length: 29 ft 
Wingspan: 44 ft 
Height: 10 ft 
Wing area: 212.5 sq ft 
Empty weight: 2,930 lb 
Loaded weight: 5,550 lb 
Power plant: 2 × 230 hp engines

General performance:
Maximum speed: ~190 knots
Cruise speed: ~160 knots
Stall speed: ~60 knots