The purpose of the part in front of the wing

Always wondered why the F-16 has a tailhook, or how big a bigmouth F-16's mouth really is ? Find it out here !
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johnwill

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Unread post28 Oct 2009, 07:50

vegasdave901 wrote:Hey, johnwill. If you've got a couple hours to kill would you label all the moving surfaces of the F-14 for me :twisted:


I'll assume you mean control surfaces, because there are many other moving surfaces that do not control flight (intake ramps, glove vanes, wings, wing covers, speedbrakes, gear doors, tail hook, engine nozzles, etc.) I'll leave that job to you.

I've included the flaps and slats as control surfaces, but they really are not such. They help to provide added lift at low speeds, but do not control airplane motion.
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johnwill

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Unread post28 Oct 2009, 08:19

mitchell_ wrote:Hi johnwill! Thanks a lot for your answer dude...could you tell me what's the LEF's maximum extension up and down?

Thanks again for the welcome john!


Mitchell, no one has called me "dude" for a very long time, probably because no one calls 70 year old f@rts "dude". Thanks!

I'll go with Raptor claw's definition of LEF full motion as 25 deg down and 2 deg up. He knows what he's talking about. But, there are two ways to define LEF rotation, streamwise and hinge line. Streamwise means you measure rotation around an axis parallel to a line drawn from wing tip to wing tip, and hinge line means, uh, rotation around the hinge line. Maybe Raptor claw can tell us which he means.

At least one member of F-16.net will testify they will go up 90 degrees under extreme provocation. Search Gums' posts for details. While you are at it, read all of his posts and you will learn a lot about many topics and be entertained at the same time. :cheers:
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mitchell_

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Unread post28 Oct 2009, 13:11

johnwill wrote:Mitchell, no one has called me "dude" for a very long time, probably because no one calls 70 year old f@rts "dude". Thanks!



ahahaha :lol: This was good...

Thank you so much for the explanation johnwill!!
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Thecrewdog

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Unread post28 Oct 2009, 20:56

I believed that the F-16 has a nose up pitch of 3 degress while in subsonic flight... Am I mistaken?
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johnwill

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Unread post28 Oct 2009, 21:57

Depends on speed, altitude, weight, external load, cg location, g, climb angle, and so on. If you are talking about 1g level flight, tip missiles only, half fuel, 400 kt, yes 3 degrees is about right. Go faster, the angle is reduced, go slower, the angle is increased.
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mitchell_

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Unread post29 Oct 2009, 00:11

...that's because of the center of pressure moving aft towards the center of gravity right? ... :roll:
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johnwill

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Unread post29 Oct 2009, 01:39

No. In 1g level flight, pitch angle is the same as angle of attack. With increased airspeed (and dynamic pressure), less angle of attack is required to generate the required lift. You are correct that if you go fast enough into the transonic range, the center of lift does move aft, but Thecrewdog specifically said subsonic flight. Also, the center of lift moving aft does not does not result in less angle of attack being required. Conversely, as the lift moves aft, more down tail load is needed to balance the airplane, and the wing/fuselage lift must be increased to compensate for the down tail load. That means more angle of attack.
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mitchell_

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Unread post29 Oct 2009, 01:50

...roger that, thanks again john!
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saberrider

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Unread post11 Oct 2017, 05:27

Raptor_DCTR wrote:Those are the LEF's (leading edge flaps). They are there to produce extra lift to the wings during high AOA and low airspeeds. The reason they are up on the ground is they are wired to the left and right main WOW (weight on wheels) switches. They are schedule to -2 degrees on the ground. The only time they move on the ground is during FLCS self test or during LEF ops checks. In flight they are scheduled as a function of AOA and airspeed. It's been a while since I've worked on the Viper but I believe what you are seeing in the picture is a +15 degree angle for take off and landing config. Conversely they will be scheduled at -2 degrees during take off until weight is removed from either main landing gear WOW switch at which point they drive to +15 until airspeed increases. Like I said it's been a while but I think the operation range of the LEFs is -2 to +20 .

In take off and landing is a fixed value +15* or if AoA is more than 13* they move down more ?Also they are able to move upward or stay in fixed 15* ?
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