Questions tagged [vtol]

For questions about vehicles capable of vertical take-off and landing.

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93
votes
15answers
17k views

Are wings any more efficient at creating lift, versus orienting the engine's thrust downwards?

As I understood from this article, wings on an airplane basically create lift by pushing air down. Maintaining the lift force expends energy because air needs to be continually accelerated downwards. ...
21
votes
4answers
9k views

How does the F-35B not flip over during transition?

As the engine nozzle rotates, the lift-fan cannot. Wouldn't this imbalance of moments around the center of gravity result in the F-35 pitching up onto its back? As can be seen at 5:14 in this video: ...
20
votes
2answers
20k views

Can you identify this fighter aircraft?

If someone can identify this aircraft, please tell me which aircraft this is?
19
votes
4answers
8k views

Can the V-22 autorotate?

Can tilt-rotors like the V-22 execute an autorotation landing? If so, are the conditions under which that would be possible (and survivable) different from a helicopter?
16
votes
3answers
4k views

Why do VTOL aircraft (F-35 or Harrier) have only one engine?

Why do VTOL aircraft (F-35 or Harrier) have only one engine? Is it because it is simpler and less expensive? Or what are the reasons?
13
votes
5answers
6k views

Why don't fighter jets take off vertically?

I've heard the claim repeated many times that some modern fighter jets have an installed thrust greater than their weight, so theoretically they could accelerate straight up. I've never actually ...
13
votes
2answers
2k views

How much thrust is lost through a curved exhaust nozzle?

In modern VTOL aircraft energy is usually directed through nozzles to achieve vertical lift. How much energy is lost when changing the direction of flow in static thrust conditions?
11
votes
2answers
2k views

Could a plane land vertically in a strong headwind?

I know there are VTOL craft meant to take off and land with a vertical trajectory. But, under the perfect wind conditions, could a normal airplane ever land (safely) with a vertical or nearly vertical ...
11
votes
2answers
576 views

Why is the F-35B's elevator not in neutral position when in vertical flight mode?

I was watching videos of F-35B taking off and landing vertically on ships when I realized that when transitioning from horizontal to vertical flight mode (I don't know the exact vocabulary to describe ...
10
votes
2answers
2k views

Can airliners benefit from vertical take-off and landing?

A vertical take-off and landing (VTOL) aircraft is one that can hover, take off, and land vertically. We have several military fighter jets, which can takeoff and land vertically (like the Harrier ...
9
votes
2answers
781 views

Can a VTOL jet such as the Harrier enter a Vortex Ring State?

I'm curious, because they obviously don't have those huge rotors pushing the air away, but they are still getting their upward thrust from somewhere. My gut says, yes, but it is more difficult. Is ...
7
votes
4answers
685 views

During VTOL landings, do Harrier pilots cut power before touching the ground?

When vertically landing, do Harrier pilots cut power before they touch the ground?
7
votes
1answer
401 views

What is the typical procedure if an engine fails during a vertical takeoff?

My understanding of VTOL aircraft (correct me if I am mistaken) is that the plane accelerates vertically until it's a bit off the ground, at which point the thrust is slowly vectored horizontally, and ...
7
votes
1answer
767 views

What is the current state of regulation regarding VTOL aircraft in the LSA category?

With quite a few concept designs in progress, I am curious what the current FAA regulations are regarding vertical takeoff and landing vehicles in the light sport aircraft category.
6
votes
1answer
1k views

How can a VTOL aircraft control yaw while hovering? [duplicate]

I watched this video of a F-35B performing a flight-hover-flight transition and was pretty impressed by the fact that it was able not only to control pitch and roll (which could be, I suppose, ...
5
votes
3answers
2k views

Why didn't we see many VTOL aircraft in the history of aircraft development?

US aircraft carriers mostly use F/A-18 Hornet. French aircraft carriers mostly use Rafale-M. Indian aircraft carriers mostly use Mig-29K. Chinese use Shenyang J-15. ... None of them are VTOL aircraft....
5
votes
1answer
234 views

How a takeoff decision point(TDP) for vertical takeoff vehicle is defined?

For a vertical takeoff vehicle like a helicopter, how the takeoff decision point is defined or computed? Look at the snapshot below, seems the height of TDP is related to the rejected takeoff distance?...
5
votes
2answers
1k views

How to calculate the power required during transition from VTOL to fixed wing?

In a VTOL, I have calculated the power required for take off and cruise which was not difficult at all. Between take off and cruise, there is a phase where the VTOL has to transition by tilting the ...
5
votes
3answers
754 views

How to calculate lift and drag coeffecients for VTOL aircraft in the takeoff stage?

How would I calculate CL and CD for a VTOL aircraft while it is in it's takeoff/landing stage? The particular aircraft is a fixed wing/quadcopter hybrid so I know that I can treat this as a thin ...
4
votes
3answers
4k views

What is the difference in VTOL technology between British Aerospace Harrier II and F-35B?

F-35B safer and looks more stable in terms of VTOL capability. What is the basic difference between Harrier II and F-35B's VTOL technology?
3
votes
3answers
512 views

Carrier VTOL takeoff or not?

In this picture, shown in a recent news article, a "shooter" seems to be giving a "go forward" command to what I believe is a Lockheed-Martin F-35 aircraft already prepped in a VTOL configuration. But ...
3
votes
1answer
375 views

Why does the US Marine Corps fly the Harrier, a VTOL or operationally STOVL aircraft?

The UK flies the Harrier because they have STOBAR carriers, but why does the United States Marine Corps fly the Harrier?
3
votes
2answers
269 views

Are there planes that can fly without wings? How would a plane be able to fly without wings? [duplicate]

Are there any planes that can fly without wings? How do they produce lift? How do they control the attitude?
3
votes
2answers
171 views

Why does Harrier have split hot exhaust nozzles?

This is a repost after the original questions were deemed too complicated. Hawker Sea Hawk shot by Smudge 9000 under CC-SA 2.0 licence. Harriers seem to inherit elements from Sea Hawk, that the ...
3
votes
1answer
853 views

How does the V22 Osprey manage such high rotor speeds without shock waves?

I read somewhere that the engineers presented an ingenious solution to the rotor tip shockwave problem, except the article didn't actually explicitly mention it. So, does anybody actually know if ...
3
votes
1answer
883 views

Why does the V-22 Osprey have twin stabilizers?

I've noticed that the Bell Boeing V-22 Osprey has a twin vertical stabilizer, while the AugustaWestland AW609 has a T-Tail. Bell Boeing V-22 Osprey with twin stabilizers. Credit: Boeing AW 609 (T-...
3
votes
1answer
353 views

Which prop location creates more lift? Leading edge or blown flap?

Which prop creates more lift? Leading edge or blown flap? In distributed propulsion there seem to be 3 prop locations: leading edge (NASA X57, blackfly), blown flap (Lillium), and pusher prop (...
3
votes
2answers
432 views

Does the Lilium VTOL wings produces lift during takeoff?

I just had a look on some of the recent development in the personal VTOL electrical aircrafts. I am wondering if the Lilium VTOL wings produces lift during takeoff? I would expect a quit high wind ...
2
votes
3answers
742 views

Why aren't tilting propellers used as an alternative for ailerons or elevators?

I was wondering what are the reasons for not using tilted propellers fixed to ailerons/elevators/elevons? Or even on wings with no control surfaces at all? Wouldn't the 2nd way of thrust vectoring ...
2
votes
3answers
248 views

Could wing tilting be a mechanism for VTOL and high angle of attack for jetliners? [closed]

My question is about turbofan airliners, could an airplane tilt its wings 90 degrees so that the fuselage horizontal axis is perpendicular to the longitudinal axis of the turbo fan. This way an ...
2
votes
3answers
223 views

How does the Urbanaero flying car move forward?

From the pictures of UrbanAero flying car: https://www.urbanaero.com/cityhawk, I can see that can achieve VTOL using the two propeller in front of and in the back of the passenger compartments. ...
2
votes
3answers
1k views

What are the disadvantages of a Tail providing lift? (tandem-wings included)

Most aircraft feature the tailplane configuration, which requires the main wing to provide higher lift than the weight of the plane itself, what seems counterproductive. Few aircraft have featured ...
2
votes
3answers
162 views

Can you have a Hybrid Turboprop-Jet engine?

To start things off I am writing this to gain information for vehicles in a story, so I am more so looking for theoretical possibilities, unless there are real world examples. The background and my ...
2
votes
3answers
512 views

Did any VTOL aircraft implement an airfoil with engine-blown exhaust?

Did any VTOL aircraft implement an airfoil with engine-blown exhaust?
2
votes
2answers
188 views

XFY-1 Vertical take-off mechanics

Hi I saw this video the other day of an XFY-1 doing a vertical take-off and landing and moving left to right while hovering. See the video Here. After watching this I had a few questions on how ...
2
votes
1answer
4k views

what are the advantages and disadvantages of tilt rotor vs ducted jet engine for a VTOL aircraft?

Please could someone summarize the main advantages and disadvantages of a tilt-rotor (the V22 Osprey) vs jet (F35) system for VTOL. I have been trying to look into this but found details very sparse ...
2
votes
2answers
209 views

Is a chambered fan more efficient than a ducted fan?

A chambered fan is not exposed to the oncoming airflow in forward flight. I am working on a VTOL design that uses a chambered fan. There will be a wing attached to top of the thrust arms. Could it ...
2
votes
1answer
430 views

Why are smaller wings in the front with these VTOL aircraft?

I would think it would be better to put the larger wings under the front or middle closer the the payload/center and have the smaller wings in the tail? Why would these designs do the opposite? With ...
2
votes
1answer
750 views

How fast do four Tire-Propellers have to rotate to lift 2000 lbs? [closed]

I just saw this come out, Goodyear's Tire-Propeller Concept – a combination tire that can also act as propeller (well, more like a ducted fan I guess). There's a neat video that goes with it, ...
2
votes
1answer
175 views

How do I calculate the total cruise power from the propellers accounting for the losses?

Let's say I have an aircraft with four propellers (see diagram below) and I am supposed to calculate the cruise power required to drive the aircraft forward. The wing creates the lift and propellers ...
2
votes
1answer
416 views

Do all the engines/propellers of a VTOL UAV need to be identical?

I would like to know if VTOL UAVs necessarily need $n$ identical propellers and motors. Have any design solutions considered the possibility of using non identical props? For instance 2 motors of type ...
2
votes
0answers
82 views

How are rotorcraft and/or VTOL aircraft handled once they get to an airport? [duplicate]

I am asking this from an ATC perspective ... my experience as a pilot is that they would make helicopters fly the same approach but once they got the airport environment in site where do they go? Taxi ...
1
vote
1answer
636 views

Has anyone successfully solo'd a helicopter with no actual flight experience?

Especially at low speed, such as during takeoff, while hovering, and while landing, helicopters are famously difficult (impossible) to control for someone with no experience. Is there a documented ...
1
vote
4answers
902 views

How do STOVL and V/STOL aircraft differ?

Wikipedia's page for STOVL begins with A short take-off and vertical landing aircraft (STOVL aircraft) is a fixed-wing aircraft that is able to take off from a short runway (or take off vertically ...
1
vote
4answers
197 views

Would a propeller extracting air from a cylinder with holes in it be an ideal lift apparatus for a VTOL aircraft?

I am wondering if enough lift can be created for a VTOL aircraft using a propeller that is extracting air from a cylinder which is closed at one end and has holes in the top half of the cylinder. ...
1
vote
1answer
230 views

What would be the Sref i.e. Reference Wing Area for Drag Build Up Calculation in case of a box wing design?

Would Sref be sum of areas of both, the front and the back wing? or just one wing? Assuming both the wings have equal areas (image below) Details - So, I am calculating drag using the component drag ...
1
vote
1answer
121 views

What's the smallest 3-blade propeller for this motor? [closed]

I've got a 15470 brushless 35kw motor from China How do I find the smallest 3-blade propeller I can use for this motor? Here are it's specs, Max Power: 35KW Max Amp: 400A Max RPM: 8500 Max Volt: 120v ...
1
vote
3answers
889 views

Disadvantages of using thrust vectoring only in an aircraft with variable rotation nacelles such as the X-19

Take a quad tilt rotor aircraft such as the curtiss-wright X-19 or even a bi-tilt aircraft such as the V-22. What would be the advantages or disadvantages of using thrust vectoring only for control ...
1
vote
1answer
113 views

I need some help to understand the rationales behind some STOVL jet designs, especially the Pegasus-Harrier configuration [closed]

In the question:Why do VTOL aircraft (F-35 or Harrier) have only one engine? Aeroailas answered why mature STOVL fighter designs only use one main engine, but did not answer why there are no mature ...
1
vote
1answer
74 views

Can a normally poorly handling airframe with high moments of inertia actually have superior flight dynamics under autonomous control? [closed]

I’m not a pilot but know a thing or two about flight dynamics. As you know there are currently quite a few aircraft under development designed for low-and-slow and (eventually) autonomous flight. ...