Friday, April 17, 2015

VSKYLABS Northrop M2-F2 Lifting Body Vehicle


VSKYLABS Northrop M2-F2 Lifting Body Vehicle





The Northrop M2-F2/F3 was the first of the heavyweight, entry-configuration lifting bodies. It was a heavyweight lifting body based on studies at NASA's Ames and Langley research centers and built by the Northrop Corporation in 1966. The first flight of the M2-F2 - which looked much like the M2-F1 - was on July 12, 1966.

A few changes from the M2-F1 design were implemented in the M2-F2, such as pilot location (the cockpit moved forward to allow the fuel tanks to be located around the center or gravity of the vehicle, in order to minimize trim changes as fuel was used on powered flight. Another reasons for moving the pilot location forward were ejection capabilities while the vehicle was still connected to the B-52, and, to improve forward visibility).

The M2-F2 was dropped from the B-52's wing pylon mount at an altitude of 45,000 feet (13,700 m) on the maiden glide flight, piloted by Milton Thompson. He reached a gliding speed of about 450 miles per hour (720 km/h).


Some flying tips for the M2-F2 Lifting Body Vehicle finals on X-Plane:

To perform the unpowered flight in correct flying weight, you'll have to empty the fuel tanks (by entering in X-Plane the aircraft/weight and balance window, and get rid of the fuel).

In unpowered flight, the aircraft is actually falling from the sky. For comfortable handling and optimum glide ratio, maintain airspeed at about 350 Knots (or Mach 0.75 at high altitudes). It's a quite steep nose-down attitude you'll have to get used to.

You can manage aircraft potential by under/overturn the flight track to the final, or use the air-brakes. 

Initial Flare begins at ~1000 feet. Don't tempt to pull-up above this height, or to reduce speed below 300 - 350 Knots before that point because you'll lose the needed airspeed for the touchdown. Flare should be executed gradually. Use the Velocity Vector Que in the HUD to fly the aircraft until touchdown.

Landing gears extension is after the completion of the flare, when the aircraft is stable at or below 100 Feet.

The aircraft is fitted with four rocket engines and fuel, in specs according to the real M2-F2. If you wish to practice the unpowered glide, you can either locate the plane around the release point (45,000 feet, Mach 0.7), or drop it from the B-52 (after selecting it for a B-52 drop out, open 'local map' and move the B-52 to the desired location and altitude. when you'll exit the 'local map' window, the B-52 with the M2-F2 will be located on that spot).

Most important: Have fun!
Now, let's go and dig some holes in the Mojave Desert :)

JetManHuss.

Typical Lifting Body Ground Track

Typical Lifting Body Approach, Flare and landing


Tuesday, April 14, 2015

VSKYLABS XF-85 'Goblin'


VSKYLABS McDonnell XF-85 'Goblin'

Including a short discussion about: Is it a plausible Dogfighter?



General information:
The McDonnell XF-85 Goblin was designed to be a single-seat "parasite" escort fighter that could be carried by a large bomber. Development of two prototypes was ordered in March 1947. Design constrains, which required the aircraft to fit into the bomb bay of a B-36 bomber (being a mother ship), resulted in an exotic result.

It's tiny, short fuselage was fitted with folding swept wings, of 21 ft 1.5 in (6.44 m) span. It was powered by a 3,000 lb (1,400 kgf) Westinghouse J34-WE-7 turbojet. There were no landing gears except for emergency skids. The fighter was intended to return to the parent aircraft and dock with a trapeze, by means of a retracting hook.


Was the 'Parasite' concept plausible?:
Although I was expecting stability and handling issues in the making of this small, short and heavy aircraft, I found out that configuring it's flight model controls, Center of Gravity and artificial stability characteristics was a real challenge; This aircraft is relatively heavy for it's size, up to 0.66 Thrust to Weight ratio, features tiny horizontal stabilizers with a 'V' configuration Elevators (which are less effective). Is this flying machine was supposed to serve as an escort fighter which could dogfight interceptors, and make it's kill by using it's gun's?...

In a fighter pilot perspective, being just small (in order to be a 'parasite' on a mother-plane), is not always the best tactics to win or even survive a dogfight. There were test flights to check the concept of being a 'parasite' on a bomber, in and out, but I'm not sure that if this project would have survived it's safety issues regarding the docking phase of it's flight, it could have survive an actual dogfight with a P-51 Mustang, a Republic P-47 Thunderbolt, or other 50' matched Jet fighter...

It's a 50' era single Jet tiny and bulky aircraft, carried by a large Convair B-36 'Peacemaker', which is a strategic bomber, deeply above enemy territory. Such strategic mission, in those days, was subjected to massive numbers of hostile interceptors, which defended their land (therefore being able to take off in large numbers). Protection of such bomber should be effective, or else, the high numbers will win. If the project of the XF-85 would have carried on, does the XF-85 would have meet it's expectations as a bomber protector? I'm not sure, and we have not discussed yet about it's very low fuel capacity and it's early jet engine fuel consumption characteristics.  

Flying the XF-85 in X-Plane can give us a little perspective on how difficult It might be, handling the the XF-85, and how we have to fly it correctly and perform aerobatic/dogfight maneuvers, despite it's unwanted 'habits'.

Flying tips for X-Plane flight simulator:
First of all - It's a 'handling and performance' project of mine, so, there isn't a fancy 3D cockpit. The HUD is you best friend for now :)

VSKYLABS XF-85 model is slightly different from the real prototype by having a fictional landing gears, an afterburner, and some modified artificial stability features. The purpose of these is to raise the fun factor of operating this aircraft in the simulator.

Flying the tiny/bulky XF-85 feels almost like flying a heavy and dirty configuration fighter jet. You have relatively low authority regarding it's handling, Pitch trim work is continues, and when maneuvering, you have to constantly manage your potential (airspeed and altitude). It's not an agile fighter as you might expect it to be (this particular version of XF-85 is setup for good balance between 'control' and 'feel', but it's not the final or 'perfect' setup, as I'll keep running my updates). 

The Thrust to Weight ratio of the flight model is the same as in the prototype. If you want to practice flying with this ratio, use 98%-99% of engine power. If you'll use 100% engine power, the Afterburner will kick in, and you'll get another 3000 lbs of thrust. Now you can 'Rock 'n' Roll' with the aircraft, compensating it's under maneuverability with extra power.

If you want to fly dogfight style maneuvers like a real 50' era jet fighter pilot in such aircraft, get your speed up to at least 300 Knots, and keep your turns at 4-5 G's. If you want to have a tight turn, use full power (99% or 100%), and turn while the nose of the aircraft is pointing below the horizon, using gravitation as an additional power source. Getting yourself below 300 Knots in a dogfight will get you in to a catch - in order to accelerate back to the maneuverability area in it's flight envelope (best continuous turn rate), you'll have stop turning, and you can't effort that time and degrees during a dogfight (unless you are going for a shot, and even though, be prepared for surprises, so, save energy!). Vertical maneuvers are not affordable or possible unless you've planned it ahead. It might be more practical to execute vertical maneuvers at low altitudes, and not below 350 Knots in the starting point.

This is definitely not my last update for the XF-85, so keep tracking my updates.

Hope you'll like it!

JetManHuss.



Friday, April 10, 2015


Valveless Pulse Jet engines as an Ultralight aircraft plausible propulsion?

JetManHuss experimental prototype: The PJSP-2 Seaplane version.


This is a modified Seaplane model of the PJSP-2 land version (which can be found in the 'Prototype' section in this website). The PJSP-2 prototype is a 'low-tech' experimental aircraft. Originally I developed this model to test the plausible configurations of a lightweight and tailless aircraft regarding it's lateral controllability and stability characteristics during take off and it's effect on the vertical stabilizer size and landing gears layout.  





The valveless Pulse Jet engine is one of the most simplest jet propulsion device ever designed, and is the simplest form of jet engine that does not require forward motion or ram air flow to run continuously. Simple air blower and initial spark are required for engine start-up, and a self resonance mechanism 'inhales' clear air and 'exhales' combusted, energetic gas flow in frequencies of up to 50 cycles per second. 

Pulse Jet engines operation is limited to low - mid subsonic speeds and altitude, mainly because of internal to ambient pressure ratio issues, to maintain it's resonance. These limitations are within a lightweight or ultralight aircraft flight envelope, therefore theoretically suitable for this kind of propulsion. 

Valved Pulse Jet engine design (such as in the German V-1 flying bomb) produces more power, and proved itself as a possible light aircraft propulsion, although being mechanically more complex and limited in continuous operation because of the life-span of it's Reed valves mechanism. I chose The 'Lockwood-Hiller' design Pulse Jets for my designs, being the most commonly built by amateurs (During the 1950's and 60's, some development work was done on the valveless pulse jet concept in the USA by Hiller and Lockwood). 


Up to these days, besides using small valveless Pulse Jet engines in small sized UAV's and experimental Go-karts, no actual use in full-scale aircraft has been recorded. Although this kind of propulsion is primitive and thrust limited, the idea of using it as a lightweight aircraft propulsion device got me trying to visualize it as a part of an actual aircraft.



A 'Lockwood-Hiller' Valveless Pulse Jets engine powers an amateur Go-Kart

I designed several prototypes of lightweight aircraft with a theoretic valveless Pulse Jet propulsion, and "wind-tunnel' tested it in X-Plane flight simulator. The exterior features of my Pulse Jet aircraft prototypes was initially for testing various experimental concepts and designs, other than actual Pulse Jet propelled concepts. The valveless Pulse Jet propulsion systems in my designs is just a 'bonus', more like a red-line of thrust and weight limitations for the designs, and mostly for inspiration. 



Valveless Pulse Jets engines on two of my experimental designs



Playing with valveless Pulse Jet engines was simple because I decided to 'deal' only with the limitations of thrust and it's best possible location around the aircraft. Because X-Plane doesn't simulate Pulse Jet engines, I configured the Pulse Jet engines in my prototypes as 'rocket' engines, with predicted thrust and fuel consumption similar to a designated Pulse Jet engine (with a thrust drop-down as altitude rising). The size of the 'Lockwood-Hiller' Pulse jet engine I've implemented in my designs is based on existing amateur engines I found over the social networks, which can produce up to 250 pounds of thrust. A practical issue in real life design would be the ability to restart the engine during flight, or after a flame-out (a small ram-air or compressed air starter device could be used for start-up during flight).

I hope you'll find it interesting, educational and fun to fly.

JetManHuss.

Now, let's fly some Pulse Jets !



Tuesday, April 7, 2015


The Gary Anderson's 'FireFlash' plausibility report (2015 edit).

Welcome to my new vskylabs.com website, which is now more of a blog (and this is my first post).

This blog is divided into 'Pages', which are the main sections of my designs. These 'section-pages' contains the information I write and download links for my designs. I will update the 'section-pages' every time a design will be almost ready, or when enough data or information will gather.

You are invited to read my posts and download my files. Comments are always welcome.

I chose to start here with my Gary Anderson's 'FireFlash' plausibility report (which I wrote a few years ago). Hope you'll find it interesting and educational:)


The 'FireFlash' will be available for download soon in a new version for X-Plane 10.

My Gary Anderson's 'FireFlash' plausibility report 



What is the 'FireFlash'?
The Fireflash, a hypersonic airliner, appeared in the episodes "Trapped in the Sky", "Operation Crash-Dive", "The Impostors", "The Man From MI.5", "The Duchess Assignment" and "Security Hazard". (Thunderbirds TV series).

It has six atomic motors that enable it to stay in the air for a maximum of six months; however, their radiation shielding must be maintained frequently, or the passengers will only be able to spend a maximum of three hours in the aircraft before succumbing to radiation sickness.
Fireflash's maximum speed is Mach 6 (approximately 4,500 mph or 7,200 km/h), and can fly at heights above 250,000 feet (76 km). 

A novel feature is that the flight deck is built into the tail fin. Like the real-world Airbus A380 she has two decks, but also features luxury facilities such as a cocktail lounge housed within glazed sections of the wings leading edges. Fireflash was commissioned by Air Terranean (a.k.a.: Terranean Airways).

Basic design features:

Wings and fuselage:
The Fireflash is a fictional hyper sonic airliner. It's estimated size is about 1.2-1.6 of a Boeing 747. The FireFlash has a long and narrow fuselage. In the front nose section of the plane there are twin Cannard surfaces. Main wing is swept and located back in the aft section. Tail section is a "T-tail" configuration, just behind the main wing location.

Engines location and arrangement:
There are six engines located up on each wing tip of the "T-tail" horizontal stabilizer, in two nacelles (three engines in each nacelle). Two horizontal fins are connected to each nacelle at the outboard side of the nacelle.


Landing gears:
Main landing gears are located in aerodynamic pods, on each wing tip of the main wing. Nose gear is located behind to the nose section (like in the XB-70 or SR-71).

Cockpit location:
The cockpit of the Fireflash is located on the leading edge of the vertical fin at the tail section (!!).

Considering these basic structural features of the FireFlash, we can see some design problems which might not allow it to perform as planned, therefore not being a plausible aircraft.

Landing gears arrangement problems: 
Locating the main landing gears in the wingtips of a giant airliner can limit it's runway operations. Many airliners taxi on the runway, while their main landing gears travels on the middle 1/3 section of the runway width. This allows for example crosswind landings with the landing gears always in the middle 1/3 section of the runway, while the nose of the aircraft pointing sideways. Sometimes, while taxiing, airliner's wing tips gets out of the runway/taxiway area, as it's wheels most of the time travels on the middle section of the taxiway.

The landing gears arrangement feature of the FireFlash will limit it's taxiing operations on standard runways/taxiways. It will also narrow the possibility for directional correction in takeoffs, landings or any runway emergencies.  Until we change the design, runway operation is limited. (or it can be operated in a very wide taxiways and runways airports).



Engine location issues:
Locating the engines way back in the tail section, and way up on the T-tail horizontal stabilizer is basically wrong. This is the most severe design flaw which badly affects the FireFlash performance: Low speed, high speed and flight ceiling limitations.  




Low speed flying - a real trap in the sky:
When flying at low speeds, lift forces on the flying surfaces are maxed out and the aircraft is relatively close to it's stall speed. Flying slow (in a normal condition), while having six powerful engines which are located way aft and way up to the center of gravity, is not so smart; when engine thrust is needed while flying slow or close to the stall speed (for a 'go-around' procedure for example), the thrust of the engines will cause a nose-down moment (because of the moments it will produce, being way above and behind the center of gravity of the plane), therefore, In a low flying speed and a high engines thrust, the nose-down moment will be much higher than the lift forces on the flying surfaces, being close to the stall speed. This will cause major problems in controlling the aircraft in low flying speeds, when high engine thrust is needed. Adding power to the engines while flying slow will force the plane to nose down without having the needed lift from the flying surfaces to encounter this moment. Stalls at low altitude are not recoverable because of this reason. 


Low speed/high power pitch input and trim limitations:
Pitch input change or trim will be needed each time power settings is changed. This equation is somewhat manageable while managing power or flight level during a cruise. But when continues changes of power setting are needed, for example: flying manually on final, each power setting change will cause a need for a pitch input correction and a pitch trim. Beside adding to pilot's workload In a low speed flight condition (takeoff/landing), a new low speed limit will occur, (which is not the 'aircraft's stall' but higher than the stall limit); It's the maximum possible pitch input in a given airspeed and angle of attack, on a given maximum engine thrust. Below this speed limit, a pitch input or trim will get to it's maximum, while the angle off attack of the aircraft (and it's attitude) remains relatively low (because the high power setting of the engines produces a nose-down moment). Control surfaces stall may occur in this situation, making the aircraft uncontrollable in the pitch axis. A 'go around' procedure in the FireFlash, is a classic example for dealing with this limit.

High altitude flying - not possible?
High altitude flying problems or the FireFlash, in general principle, are similar to it's low speed problems. high engine thrust is required to obtain high altitude sustained flight (simply, this is because of the thin atmosphere). Lift forces are reduced as the flying surfaces not generating enough lift to counter the needed engine thrust moment (because of it's location far behind and higher than the center of gravity of the aircraft). Adding thrust to accelerate/maintain a high airspeed and high altitude will cause the FireFlash to have a high pitch-down moment, and, a low-speed limitation which under it, flying surfaces will stall or reach maximum pitch input while trying to eliminate the pitch-down moment.

Hyper Sonic flight - not possible?
The FireFlash designed to be a Hyper sonic airplane. Maximum thrust is needed to reach Hyper sonic speeds, while high drag values are rising. To reach speed of mach 7, with it's given weight and size, the thrust must be so powerful, reaching a new high-speed limit, which above it, leveled flight will not be possible, because the flying surfaces will not be able to encounter the thrust and maintain the airplane leveled. So, practically, reaching Hyper sonic speeds with the FireFlash is not possible. 


Cockpit location issues:
Locating the cockpit inside the leading edge of the vertical fin, way back in a very long tail section will cause severe limitations in the pilot's field of view, especially when landing and taking off (taxiing is also a challenge). The needled fuselage and the Cannard surfaces will hide the runway.Think about the Concorde, reducing it's nose when landing in order to allow the pilots to see the runway. In the FireFlash, there are couple hundreds of feet of fuselage and nose ahead of the cockpit. We have to design the FireFlash to generate it's lift in relatively low angles of attack, and land at relatively high speeds. We can use cockpit camera (like in the XF-103).

Now, when we theoretically understand the basic design features and it's effect on flight, here are some practical flying tips for the FireFlash:
(The 'FireFlash' will be available soon for free download here, so you could practice your flying skills, flying it in X-Plane).

Takeoff:
Lift-off speed is about 200kts (this number is reflecting the equation off all of the FireFlash features, mass and configuration, in X-Plane advanced flight simulation). Do not use 100% power. It will "GLUE" the nose gear to the runway and you might not take off on the given runway. Use flaps (1 notch). If you have good hands - at about 190kts, reduce power to 50%. It will allow the canards to counter engine thrust force, but, you will have to manage power and stay away from the low-speed-limit that will cause the engine thrust "take over" the forces equation over the flying surfaces lift forces, and pitch you down. As you are airborne, retract flaps, trim and add power gradually until there is enough airspeed to fly safely.

Landing:
Slow down and extract the flaps. Final speed at 250kts. You can fly the final slower, but it depends on your trim skills, and the low-speed limitation. Take into consideration your wing-tips landing gears location, and the cockpit location. When flying at 250kts, with flaps down, you can use the HUD and place the velocity vector on the touchdown zone. It is surprising, but it can be done, even when looking forward from the vertical fin's cockpit.

The rest of the flying-phases are very educational and fun. Once you up in the air, you are on your own!


The FireFlash in some action:
(This is X-Plane v9.70 video. X-Plane v10 version will be ready soon)





Wednesday, April 1, 2015

VSKYLABS 'Scratch Built RC Legends' project


VSKYLABS 'Scratch-Built RC Legends' project
A complete Radio Controlled simulation pack for X-Plane 10.
This project is aimed to be a professional and a best choice RC simulation.
(Linux/Mac/Windows compatible)



Project overview:
The package is including an interactive ('everything you see can damage your plane') R/C airfield, equipped with take-off ramps, pylon poles, obstacles etc. View point of the R/C pilot is set-up to the right spot, ready for action.

'Scratch Built RC Legends' flying Airfield - 'RC-CITY':
The flying field is perfectly tailored to RC operations and training.
The objects in the environment are physically existing, so the airplane can collide and interact with them (antenna's, cars, ski-jump ramps, pylons, fences etc.).
The objects are also arranged carefully in the flying area so it may give the R/C pilot clues about depth perception for training, since there is no real depth perception in simple 2D monitors. Pilot position is well thought of and placed at the right spot and elevation.

Model Airplanes in the package:
The package contains detailed and amazing 'giant scale' R/C model airplanes such as
the D.H.88 Comet, the P-38, the Grumman SkyRocket and more. Some models are 'FPV' ready, which means that you can fly them as real FPV models.
Flight performance of the models is the most important part in the concept, and it is simply AMAZING.






Saturday, March 28, 2015

VSKYLABS NASA'S M2-F1


VSKYLABS NASA'S M2-F1 Lifting Body glider 

(Current version is for X-Plane 10.32+)

Thanks to "Active" (user at the X-Plane.org) for inner steel structure and pilot (from the pilot collection made by Beber).




(From Wikipedia, the free encyclopedia):
The lifting-body concept originated in the mid-1950s at the National Advisory Committee for Aeronautics' Ames Aeronautical Laboratory, Mountain View, California.
By February 1962, a series of possible shapes had been developed, and R. Dale Reed was working to gain support for a research vehicle.
The construction of the M2-F1 was a joint effort by Dryden and a local glider manufacturer, the Briegleb Glider Company.
The budget was US$30,000.
NASA craftsmen and engineers built the tubular steel interior frame.
Its mahogany plywood shell was handmade by Gus Briegleb and company.
Ernie Lowder, a NASA craftsman who had worked on Howard Hughes' H-4 Hercules (or Spruce Goose), was assigned to help Briegleb.
Final assembly of the remaining components (including aluminum tail surfaces, push rod controls, and landing gear from a Cessna 150,
which was later replaced by Cessna 180 landing gear) was done at the NASA facility.
The wingless, lifting body aircraft design was initially conceived as a means of landing a spacecraft horizontally after atmospheric reentry.
The absence of wings would make the extreme heat of re-entry less damaging to the vehicle. Rather than using a ballistic reentry trajectory like a Command Module, very limited in maneuvering range, a lifting body vehicle had a landing footprint the size of California.


GENERAL FLYING TIPS:
Setup simulation with the option "Start with engine running"
(It will enable power for pitch trim).

Lateral Field-Of-View recommended setting is 65 Degrees.
The glider has no engine, but has landing assist rocket (JATO) for the flare phase.
You can use "Location/Local Map" window to set the M2-F1 at desired location and altitude.
(Set the Airspeed to 100 Knots).

The real M2-F1 had a speed limit of 120 Knots. Use pitch attitude to keep the airspeed during the glide.
Use the pitch trim to release stick loads during the glide.
Use the HUD for easy reading of instrumentation data.

LANDING INSTRUCTIONS:

Glide/Final
Do not fly below 80 knots, and higher than 120 knots.
(The glider initial trim is set up to maintain a ~110 Knots "hands-free" glide).
Lift to drag ratio is about 2.8 - this glider "falls" from the sky, with no wings to flare.
So, keep your airspeed not below 110 Knots.

Flare
Flare technique needs practice. You can use the landing assist rocket to improve touchdown.
Use the HUD to practice flare height:
At about 300 feet above ground level, start the flare firmly.
(RADAR ALT will start to show readings below 2500 feet)

External visibility during the glide and the flare is bad, use the nose windows to see the runway.

Usage of the landing assist rocket is from 350 feet, it will give you a slight "push" for 10 seconds to soften the landing.


Newer video:

Older video:


Friday, March 27, 2015

VSKYLABS 'Greyhound'


VSKYLABS "Greyhound"
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.


Project overview:
The VSKYLABS GREYHOUND is a high performance two seat light Jet aircraft, built around two General Electric J85 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.

VSKYLABS Greyhound general specs:
Empty weight: 5300lbs
Maximum takeoff weight: 7500lbs
Length: 26 feet.
Wingspan: 30 feet.
Power plant: Two General Electric J85 Turbojets engines, 2050lbs of dry thrust, 3550lbs with full afterburner.

How to fly the Greyhound:
It's a very light and powerful sport plane, not a Jet-fighter. Handle it with care.
Use the Air Brake on final and landing.
Leading edge Flaps are automatically extracted below 260 knots.
Most important: Have fun!!!