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Newbie Joined: Apr 25, 2006 Posts: 4 Status: Offline

I am a post graduate student of Indian Institute of Science (IISc) India and doing academic project work on automatic landing of F-16 aircraft. Can anyone help me by giving the following information?

(1) Typical landing distances with and without drag chute.
(2) What is the typical landing speed?
(3) At which speed is the aircraft derotated (pitch down) for nose wheel touchdown?
(4) What is the typical pitch angle at touchdown and till the start of derotation?
(5) When is the thrust cutoff?
(6) Which is the braking speed during the ground run?
(7) What are the typical increment in the drag and lift coefficients due to spoilers and airbrakes? When are they activated?
(8) Is reverse thrust employed while landing? Is so what is the value?
(9) What is the value of drag offered by the drag chute?

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1. No clue
2. Anywhere between 170 and 120 knts depending on weight I´d say. fast heavy landdings might be outside the spezifications but still doable
3. Id guess when it becomes impossible to keep the nose up
4.13° AOA
5. No idea
5. same
6. again
7, Airbrakes well before toughdown. Spoilers. It does not have any
8. the F16 does not have reverse thrust
9. beats me

More details stright from the horse mouth here
http://www.codeonemagazine.com/archives ... index.html

Newbie Joined: Apr 25, 2006 Posts: 4 Status: Offline

Thanks a lot hansundfranz.

I don't know what the minimum landing distance is for sure, but I was once told by a pilot that they wont land on a runway that is less than 6000 ft. but that may be an air force wide safety thing and not something specific to an F-16.

Newbie Joined: May 14, 2006 Posts: 6 Status: Offline

(1) Typical landing distances with and without drag chute.
-Without dragchute, depending on fuel weight+stores around 2700+ ft.
-Haven't flown with dragchute yet.

(2) What is the typical landing speed?
-133kts+4kts per 1000lbs of fuel/stores(A-model), so mostly around 141kts(+20kts= final turn speed)

(3) At which speed is the aircraft derotated (pitch down) for nose wheel touchdown?
-Not specified in regulations, but mostly between 80-100kts.

(4) What is the typical pitch angle at touchdown and till the start of derotation?
-13 degrees aerobrake

(5) When is the thrust cutoff?
-what do you you mean with thrust cutoff?

(6) Which is the braking speed during the ground run?
-No idea what you mean by this sorry.

(7) What are the typical increment in the drag and lift coefficients due to spoilers and airbrakes? When are they activated?
-No idea; no spoilers, just speedbrakes; speedbrakes are open to 43 degrees during landing, as soon as nosewheel touches the ground the pilot overrides speedbrakes to 60 degrees.

(8) Is reverse thrust employed while landing? Is so what is the value?
-No

(9) What is the value of drag offered by the drag chute?
-Wouldn't know

Newbie Joined: Apr 25, 2006 Posts: 4 Status: Offline

ViPeR,
First of all let me thank you for the excellent information you have given me. Two clarifications :
(1) Thrust cut-off : What i meant by thrust cut-off is the throttling down to minimum thrust level. What is the minimum thrust value when the throttle is minimum. Does the throttle setting takes negative values also ? eg. -0.3
(2) Braking speed : When is the main wheel brakes activated ? Is it done even when the nose wheel is in air ? what is the approximate aircraft speed when main wheel brakes are activated ?

Biju wrote:

First of all let me thank you for the excellent information you have given me. Two clarifications :
(1) Thrust cut-off : What i meant by thrust cut-off is the throttling down to minimum thrust level. What is the minimum thrust value when the throttle is minimum. Does the throttle setting takes negative values also ? eg. -0.3
(2) Braking speed : When is the main wheel brakes activated ? Is it done even when the nose wheel is in air ? what is the approximate aircraft speed when main wheel brakes are activated ?

I'm not an expert but:

no
under 60 kts IIRC

Newbie Joined: May 14, 2006 Posts: 6 Status: Offline

Oh ok, now I see what you meant.

You go to idle power as as soon as 'landing is assured', so most of the time at the beginning of or during the flare.
There are no negative values to indicate idle. Idle power, according to the Dash-1, should be between 60-76% rpm(the exact rpm at idle varies off course with Outside Air Temperature and pressure altitude at the airfield elevation)
Wheel brakes are applied as soon as the nose gear comes down after the aerobrake, so approximately 80-100 kts. As soon as the nose touches the ground, the speedbrake switch is held so the speedbrakes go to 'override', which causes the speedbrakes to extend all the way to 60 degrees, instead of 43 degrees when the speedbrakes are all the way open with the (nose)gear down.

I hope to have answered your questions.

Newbie Joined: Apr 25, 2006 Posts: 4 Status: Offline

Thanks a lot ViPeR.

I just want to add to the 2. above, that braking when nosewheel touches the ground is the normal under most circumstances. It's allowed to apply brake power even with the nosewheel on the air (when rwy length is critical) depending on configuration. For usual configurations (WT+ Air to Air load) this speed is up to 120Kn approximately (without having a "Hot Brakes" situation).

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