Questions tagged [vtol]

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

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94 votes
15 answers
19k 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. ...
user9037's user avatar
  • 973
21 votes
5 answers
11k 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: ...
AllTradesJack's user avatar
20 votes
2 answers
21k views

Can you identify this fighter aircraft?

If someone can identify this aircraft, please tell me which aircraft this is?
KARTIK GURNANI's user avatar
19 votes
4 answers
12k 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?
feetwet's user avatar
  • 2,274
16 votes
3 answers
5k 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?
R S's user avatar
  • 377
15 votes
3 answers
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?
usernamechecksout's user avatar
13 votes
5 answers
7k 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 ...
raptortech97's user avatar
  • 5,128
12 votes
2 answers
885 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 ...
Manu H's user avatar
  • 16.5k
11 votes
2 answers
3k 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 ...
AJMansfield's user avatar
11 votes
2 answers
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 ...
anshabhi's user avatar
  • 11.5k
9 votes
2 answers
1k 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 ...
Bassinator's user avatar
  • 5,490
7 votes
3 answers
2k views

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

US aircraft carriers mostly use the F/A-18 Hornet. French aircraft carriers mostly use Rafale-M. Indian aircraft carriers mostly use MiG-29K. Chinese use Shenyang J-15. And so forth. None of them are ...
user avatar
7 votes
4 answers
900 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?
jwzumwalt's user avatar
  • 11.4k
7 votes
1 answer
507 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 ...
cat40's user avatar
  • 343
7 votes
1 answer
838 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.
David's user avatar
  • 1,349
6 votes
2 answers
2k 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 ...
sai teja's user avatar
  • 437
6 votes
1 answer
2k 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, ...
Silent Inky's user avatar
5 votes
1 answer
1k 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?...
VvV's user avatar
  • 1,579
5 votes
3 answers
2k 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 ...
user34490's user avatar
4 votes
3 answers
693 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 ...
user32016's user avatar
4 votes
3 answers
3k 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 ...
zaumo's user avatar
  • 55
4 votes
3 answers
6k 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?
user avatar
3 votes
3 answers
865 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 ...
FlegmatoidZoid's user avatar
3 votes
3 answers
292 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. ...
Faito Dayo's user avatar
3 votes
1 answer
646 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?
baba yaga's user avatar
  • 131
3 votes
2 answers
506 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?
Mitchell Thomas White's user avatar
3 votes
2 answers
201 views

Why does the V-Bat not counter-rotate?

V-Bat is a VTOL aircraft built by a company called Martin UAV. It seems to have a single pusher propeller. But then why does it not counter-rotate to balance the rotation of the propeller? Any clear ...
Atharva's user avatar
  • 33
3 votes
3 answers
517 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 ...
Markitect's user avatar
  • 133
3 votes
2 answers
940 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 ...
CrystallizedRefresher's user avatar
3 votes
1 answer
2k 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 ...
Arth Patel's user avatar
3 votes
1 answer
1k 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-...
SharkyPanda's user avatar
3 votes
1 answer
903 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 (...
Fred's user avatar
  • 1,059
3 votes
1 answer
1k views

Why do F-35B jets hover with their weapons bay doors partially open?

This is an interesting phenomenon noted for F-35B aircraft during vertical flight and vertical landing. They will do so with their weapons bay doors partially opened. ...
Romeo_4808N's user avatar
  • 73.5k
3 votes
2 answers
494 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 ...
Mokus's user avatar
  • 131
3 votes
2 answers
245 views

How is the power gained from exhaust of an engine calculated?

Ryan XV-5 Vertifan used exhaust gas from engine to rotate the fan inside the wing. If I want to design an aircraft using this propulsion system how can I calculate how much power I can get from a ...
Eaza's user avatar
  • 121
2 votes
3 answers
317 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 ...
roma salah's user avatar
2 votes
2 answers
472 views

Different Engine/Prop Sizes on Same Wing/Single Craft?

On a four propeller/engine wing, I’m wondering if theoretically at least, you could have a larger engine near the root of the wing with smaller engine(s) further out on the span..?.. If you could have ...
Greg Dean's user avatar
2 votes
2 answers
418 views

How free are VTOL pilots to hover?

When piloting a Harrier or F35 can the pilot just hover at will? Or is this possibly something that will eat up lots of fuel, and should only be done when planned? (like for landing) Is spontaneously ...
matthias_code's user avatar
2 votes
4 answers
2k 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 ...
cyberservant's user avatar
2 votes
3 answers
641 views

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

Did any VTOL aircraft implement an airfoil with engine-blown exhaust?
Francis L.'s user avatar
  • 2,524
2 votes
4 answers
339 views

What is the decrease in power when a drone is in descent?

For a quad-copter, or a fixed-wing drone with quad-rotor formation, how much would the power of the motor decrease when a constant speed descent is needed to bring the drone back to the ground? Does ...
Faito Dayo's user avatar
2 votes
2 answers
217 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 ...
FutureCake's user avatar
2 votes
1 answer
5k 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 ...
SRawes's user avatar
  • 1,211
2 votes
2 answers
313 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 ...
Tom Daily's user avatar
2 votes
1 answer
668 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 ...
Daniel Caoili's user avatar
2 votes
1 answer
1k 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, ...
CrossRoads's user avatar
  • 8,785
2 votes
1 answer
232 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 ...
sai teja's user avatar
  • 437
2 votes
1 answer
452 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 ...
Mirko Aveta's user avatar
2 votes
0 answers
95 views

The cost of maintaining VTOL devices

Which device for VTOL flight costs the most to maintain for a given number of flight hours? A tiltwing mechanism? A 2D thrust-vectoring nozzle (vectoring only between VTOL position and cruise ...
user39178's user avatar
  • 313
2 votes
0 answers
85 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 ...
Jason Reskin's user avatar