Forum: F-16 Procedures

Ever watched the gear on a B-52 during a crosswind landing?

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I gotta comment on this thread!

You non-Viper guys don't get it.

STBY has it right.

Only way to 'deep stall' the F-16 is to creep up to an attitude slow enough to keep the thing from pulling over all the way thru the horizon. The tail moves further leading edge up to decrease AoA, and as speed gets below 80-90 knots the plane settles into a nifty 'floating leaf' looking doofer.

AoA is above 25 degrees, so the 'pitch over ride' switch becomes active and you can 'rock' your way outta the deep stall. The original team could not find a 'stall' in the jet. Only a nugget that kept the thing climbing at about 80=85 degrees of pitch discovered it.

If you yanked and banked all the time you couldn't ever get into a deep stall. Only if you had the wings fairly level and were slowing down while climbing at 80 degrees of pitch or so could you get into the deep stall.

Finally, the FLCS will NEVER allow you to stall the Viper. Sure, at 40 or 50 degrees AoA the thing might actually stall in the conventional sense. Hell, might even be a higher AoA if you have touch and don't have aileron or rudder inputs. I'll try to scan my CL curves to show you! The LEF's really smooth out the normal 'break' in the curve, so the plane starts to 'mush' before it ever 'stalls'. Directional stability was the problem at high AoA, not the 'stall' .

Habu wrote:

Name one modern GA aircraft where this applies.

DiamondStar DA20 and DA40, Im pretty sure the new Cirrus S20 and S22 are that way. I think more aircraft in the future will be that way too.

Well yeah, look at the design, it's much like a Grumman Cheetah's. It's a design quirk and not indicative of an industry wide trend, or evolution in design.

I disagree. The Diamond and Cirrus are the hot thing on the market right now (as they should be, they are NICE) and so future designs will attempt to copy them.

Besides that, think of the advantages vs disadvantages of having the differential braking. They are much easier to steer for student pilots. They eliminate the weight of the steerable nosewheel system(thats a biggie). It would be much smarter to design small planes that way.

But it's not a new or revolutionary concept. If anything you can say it's come full circle. I'm not knocking it at all, just stating that it's nothing new. It's funny though, many things are happening like that, and all around the centennial of powered flight. What did I see at Edwards in October? An F-18 with a variable camber wing...and right in front of it, a Wright Flyer replica, complete with wing warping mechanism....full circle indeed.

The first jet to shoot down another jet used a nondirectional nose gear, the Lockheed P-80, then F-80. The TP-80C, TF-80C, T-33A also used the same nose gear and differential braking for ground steering. It may work great for a little aircraft that can’t pull 6 g’s and carry weapons, but for a 15,000 lb fighter, it doesn’t make it the worlds easiest a/c to taxi. And lord help your beer budget if you ever cock the nose wheel! That’s why the joke about more people washing out cause they couldn’t taxi a T-Bird versus washing out for trying flying it.

Me and my roommate (another aerospace student) were discussing this the other day and we came to the conclusion that larger jets couldn't use differential braking as the primary method to turn. Not enough savings in weight on such a big plane and it would be pretty hard to turn.

If by "larger jets" you mean KC-135, KC-10, C-130 (OK...it's a turboprop), C-5, etc. you're right. Diff braking wouldn't have enough cajones to turn with authority. The Heavies use a hand operated tiller on the captain's side to turn the nosewheel.

I thought we were talkin' about deep stalls in the Viper? How'd we get on differential braking? Question

An important factor in the effectiveness of differential braking is the ratio of wheelbase to wheeltrack - that is, the ratio of the distance between the left & right mains to the distance from the mains to the nosewheel. For "heavies" you can see this ratio would be much different than for, say, an F-16.

Oh good lord...

I don't really know much anything about differential braking. In the T-38 you could use differential thrust to turn, even with the engines side-to-side. I never use differential braking in the Viper. I try to use the brakes as little as possible before takeoff as I don't want them to be even slightly warm if I have to abort. I always factor the recent landing in to my takeoff-EP matrix when I do a pit-and-go sortie.

STBYGAIN wrote:

Oh good lord...

Easy there STBYGAIN! Deep cleansing breaths. Think happy thoughts - like a Fulcrum cemented in the LCOS pipper with only 2 Gs on the plane and a full drum of 20mm. Smile

MMmmmmm...guns kill... mmmmm

B-2s use differential thrust in certain flight modes - without touching the throttles.

Never used diff thrust in the 38... engines aren't strong enough to make corners. (heh heh)

The key to using the brakes in the viper:.... Apply them firmly, but shortly, and then "coast" up to speed again. Riding the brakes is the most dangerous thing you can do.

Cylon

Can someone help me find a Viper instuctor that is qualled in high angle of attack recovery for a mission for AeroGroup. Must be curent with in 30 days.

Ditch

Need vitamin 'G'

Forum: F-16 Procedures

Deep stall recovery