Forum: F-16 Simulators

Any F-16 expert,

recently a Falcon dogfighting league has been set up. Some people found out that in Falcon4 you can set the Alt Flaps switch to extend, to get the TEF's extended and this will give a better turn radius. Off course they bleed of energy while it is extended.

But would this switch ever be used during real life BFM? Could this damage the airplane at high speeds?

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I don't think the alt flaps switch is used in the real jet except for emergency situations like FLCS failure or something... I'm not an expert though, I'm sure there's some dudes around here who can answer this question way better.

Not an expert either, but I think that it wouldn't be used. Sure it gives a quicker turn radius but for how much, since it would be a major energy dumper ? Additionally, it would be a great disadvantage when you would need that energy, and much more fuss to bring them up. That means one would sacrifice valuable time and SA, critical in today's fighting.

I remember reading that the Spitfire in WWII did miracles with one bit of flaps, but then the sky fighting was quite different back then. You now have countermeasures and tactics, but so does the enemy who can blow you out of the sky without you even noticing him if you're not careful. And I believe one more switch to play with in the cockpit takes all the advantage of HOTAS you have on modern jets for dogfighting. Smile

That does not come of course from anyone even remotely qualified to speak about the F-16 but it sounds logical, and if the opposite happens, I'm willing to get corrected Mr. Green

Hi,

Nothing in life is perfect, and a dog-fight is no exception. It requires several things:

* A great aircraft
* A great pilot
* An aircraft that is operating well.

If the defensive aircraft makes a mistake, he's dead. If the chasing aircraft makes a mistake, he's dead. If the chasing aircraft could gain that key-hole opportunity to get an advantage on his opponent by changing the config of his jet for 2 seconds, then I can't see why he probably wouldn't do it, even if it meant risking slight damage to the jet. In a life or death situation, you'll do what it takes to win.

Slight damage vs. death - you pick.

--TangoShadow.

I'm not a pilot so I'm not an expert either but from a specs standpoint I don't think the ALT FLAPS switch is not used in BFM. I believe it is placed to EXTEND when on final. This alters the wing camber and provides more lift at slower speeds, the LEFs also work with the FLAPERONS to change lift properties of the wing. Otherwise, the FLCC or DFLCC provides all position calculations for the FLAPERONS while in flight and the ALT FLAPS switch is in NORM. The stabs are used more for pitch control, while the FLAPERONS provide roll control, although the stabs and FLAPERONS do work together in the pitch and roll axis. The FLCC or DFLCC will limit G's depending on A/C configuration(fuel, stores, weight).

Elite 1K Joined: Aug 19, 2004 - 09:19 AM Posts: 1092

ALT FLAPS switch is not intended for gear-down flight since the trailing edge flaps (TEFs) are automatically deployed and automatically scheduled when the gear comes down. The ALT FLAPS switch is a function for gear-up flight. From what I've read in the TOs, use of ALT FLAPS switches the FCC to standy gains as opposed to cruise gains and the leading edge flaps (LEFs) are locked in place at 15 degrees (I think it's 15 but I know they are fixed at some angle). Having LEFs locked and using standby gains instead of cruise gains would likely make high AoA manevering risky business. Your roll rate is also reduced in standby gains similar (or perhaps exactly the same) as when you deploy your gear. Having locked LEFs will result in increased buffeting and decreased departure resistance at high AoA. Also, standby gains are only designed for use in certain regions of the flight envelope. I don't remember the exact details.

The use of TEFs in a dogfight would probably be more viable if the F-16 didn't also use the flaps as ailerons (i.e. flaperons). If flaps could just be used as flaps then it would be easier to schedule them effectively and efficiently in combination with the LEFs. From pictures I've seen, it looks like the F-22 does use its TEFs and LEFs in conjunction... at least at low speeds. Just look at airshow pictures and whatnot... the TEFs are often seen deployed to some degree with the gear up. This makes sense since there was a lot of research done a while back (with an F-111 I believe) showing the benefit of variable camber wings throughout the flight envelope. This basically means the use of both LEFs and TEFs to optimize the aircraft's drag polar and lift curve throughout the flight envelope. The F-16 was only designed to use the LEFs throughout the flight envelope to optimize performance.

Johnny Cash-

You would not use the ALT FLAPS switch to get and edge in turning ability during BFM. The only time it would get used is during an emergency procedure.

Salute!

Maybe in the Falcon 4 sim you get better turn, but you sure as hell don't get better roll or stability. See above.

You also get increased drag.

The little jet turns quite nicely on the limiter at veeeery low speeds, and you don't have to worry much about departing.

If you have to try something like ALT FLAPS, you're already in trouble, IMHO.

Out,

Elite 1K Joined: Aug 19, 2004 - 09:19 AM Posts: 1092

Unfortunately, the flight model code in Falcon 4 does not allow for all the adverse effects you'd get from using the alt flaps switch while pulling high AoA and whatnot. I co-developed the "high fidelity flight models" (HFFMs) for Falcon 4.0's BMS 2.0 exe and while we did get the BMS coders to fix several major code deficiencies and bugs, you can still fly "care free" with the alt flaps switch in the extend position. There was code added to limit the roll rate and put you in, I think, "landing gains" (similar to standby gains?). Regardless, you still won't feel any buffeting and won't be prone to increased departure succeptability while using alt flaps and flying around at high AoA. The LEF coding in Falcon 4 is way to simplistic as well and doesn't actually model the true effects the real LEFs have on the F-16's lift and drag polar. You will have a very accurate F-16 flight model using the HFFMs when the LEFs are auto-scheduled and alt flaps is not in use. Do anything like lock the LEFs or use the alt flaps switch and you will no longer have flight performance that closely models the real thing under the same conditions.

You will get a good amount of extra drag with alt flaps deployed. You shouldn't get any sort of advantage from locking the LEFs in place. You could get an advantage in very specific situations using alt flaps, but only if your opponent wasn't expecting you to utilize this function. For example, if your opponent got into a low speed horizontal scissors or with you and you used your alt flaps switch while he did not, you would probably have a bit of an advantage. You'd be able to fly slower while maintaining about the same turn rate as your opponent (assuming s/he was not using alt flaps too). This would give you a turn radius advantage. Also useful for 1 circle fights that begin at slow speed. These generally turn into horizontal scissors anyway if someone doesn't get gunned at high aspect prior to the merge. You will not be able to change your lift vector as fast with alt flaps in the scissors which may present a problem.

If your opponent is smart and knows you're fooling with alt flaps, he'll keep his speed up and utilize the vertical on you quite a bit when he sees you've gotten slow. Alt flaps in Falcon 4 DEFINITELY makes slow speed vertical plane maneuvers inefficient and dangerous. They'll also hinder your acceleration a bit under 370 knots and especially in the low 200s or below. Extending out of a bad situation with alt flaps engaged is not a good idea.

ALT FLAPS you use after lowering the Landing Gear using emergency ALT GEAR extension. Since the Landing Gear Handle may be useless.

Elite 1K Joined: Aug 19, 2004 - 09:19 AM Posts: 1092

f16doc wrote:

ALT FLAPS you use after lowering the Landing Gear using emergency ALT GEAR extension. Since the Landing Gear Handle may be useless.

So the ALT GEAR doesn't lower the TEFs? Didn't know that.

Salute!

Yeah, Rap, both the gear handle and the ALT FLAPS doofers are just electrical switches.

The emer gear involves rotating and pulling out the little wheel thingie on the end of the handle. One of the only mechanical connections to ANYTHING in the whole jet.

BTW, only time I ever used ALT FLAPS was trying to stay slow enuf to get tail numbers off a Cessna that was violatin restricted airspace. What a hoot.......

later,

Elite 1K Joined: Aug 19, 2004 - 09:19 AM Posts: 1092

Gums,

I knew that ANG Vipers used the alt flaps switch to stay with slow flying targets. Were you in the ANG? Do tactical birds do any regular intercept duty over US airspace?

-Raptor

f16doc wrote:

ALT FLAPS you use after lowering the Landing Gear using emergency ALT GEAR extension. Since the Landing Gear Handle may be useless.

Hi, and a big "CONGRATS" to your forum - very great infos!!!!! Cool

I am working on a home-built pit (for Falcon [Link pending approval] and other pc-based sims)...

Now I am looking for some details on the knobs and switches, [Link pending approval]

- where do I find the electrical switch for the ALT FLAPS ?
- what are three litle white round things on the lights (taxi/landing) switch (near the gear-handle)... (lights???) ?
- what is the "DN lock rel" near the gear-handle (the safty-button for the gear-handle !?)
- the ALE-40 CCU (chaff dispenser) comes with a red security-switch (arm/test/off)... why is that??? ( I know why there is a security-switch with that "nuclear" thing on the right side of the cockpit - but for the chaff ????)
- I don´t find photos of the canopy-open [Link pending approval] do you have a tip!?

and some [Link pending approval] Shocked

Maybe (I am sure Wink

) you have a very magic link in mind to help me out of my "[Link pending approval] handbook- for"[Link pending approval] !?

Lot of greetings, Sun Very Happy

Here's a beautiful example of ALT FLAPS at work