side slips?

[Guest Piperpilot2004]

I have never seen a military aircraft enter a slip on landing. Can you perform a safe one in a fighter? Just curious if this is something you would only do in a GA aircraft or not. I know it wouldnt be a good idea in a big aircraft, and the airlines dont like it. stupid question, but I guess thats what this site is for, questions mate.

[Baseops.Net]

Don't do a slip in UPT - in fact don't perform a slip at all. It is considered bad (technique/ procedure) to fly un-coordinated. Especially in non-centerline thrust (and/or multiengine) aircraft. UPT Students with a lot of Gen Av time seemed to have a penchant for saving a terrible pattern with a slip.

Incidently, I had to perform a slip on my ATP checkride... it was a required item!

[Guest FlyingAgain]

slips are a syllabus item for T-6s. They're only done with the gear up at 125 KIAS. They're taught in case you find yourself engine-out and way high on the way to high key. slipping in the pattern isn't necessary if you use the correct pitch/power settings and trim. if you're too high on final, you should go around.

[Guest purplecaddis]

Not encouraged or good technique but, I knew quite a few old-timers, i.e. Vietnam era pilots, in the Herk that would do it to save a high short final.

[BFM this]

The tweet would slip ok, but like everyone said, it's considered poor form. Slips in the T-38 are actually a good way to kill yourself, especially in the pattern. Has to do with the swept wing. I spent my first dozen rides or so reminding myself repeatedly NOT to do cross-controlled landings.

[Guest kirkhac]

Also, you shouldn't slip with the gear down in the T-6 because you then put yourself in position to land with a cocked nosewheel. I doubt that this is a problem with other airframes though.

[Guest rotorhead]

Okay, educate this fling-winger...

...In a helo, you either land directly into the wind (who cares about runway axis!!) or you make sure you are aligned (read: cross-controlled) so the landing is absolutely straight heading-to-groundtrack or you'll roll-over in a brownout landing (dynamic rollover and several other nasty helo phenomena)...

...I've also got hundreds of hours in Cessna 150/172/175/182 (which a cross-controlled landing is just peachy)...

...so my question is, how the heck do you land a tweet WITHOUT cross-controlling it in a crosswind?

[Guest comanche]

I've never flown them but I'm guessing crabbing into the wind with a kick out at the last second to align you.

[Mambo]

A slip and cross-controlling in a xwind I believe are two different things. You can still cross-control in an aircraft and fly coordinated, your nose is just not pointed in the direction of the runway, but your wings remain level, or the upwind wing is dipped into the wind slightly(right?). A slip, as mentioned above, would be kicking the rudder opposite to the wing down side (in a turn) and allowing the aircraft to slip through the air, creating more of a descent than a normal coordinated turn. Just a guess, I'm only an FE...I'm sure someone could probably explain it better...

[Ram]

Originally posted by flyinjunky:

Slips in the T-38 are actually a good way to kill yourself, especially in the pattern. Has to do with the swept wing.

Not to mention the 30 degrees of rudder deflection with the gear down...

The combination of all that rudder authority and the high AOA at final approach speeds has a chance of flipping the jet on its back. It's one of the reasons we land the '38 in a crab with high crosswinds.

[Guest Piperpilot2004]

thanks for the responses guys! Just wondering..

[ellsworb]

Actually, slipping during a Xwind is NOT flying coordinated. There are 2 types of slips. Forward slips and side slips. The forward slip is what is used to lose altitude quickly, but still fly in a straight line. The side slip, however, is used to keep the longitudinal axis of the aircraft aligned with the runway. However, the amount of aileron used is directly proportional to the amount of Xwind experienced. The wings could be level or the upwind wing could be slightly down. In any case, this is NOT coordinated flight. I have no idea how it affects jets, because i'm in the T34 right now and we use slips like crazy and all my previous time is in tailwheels.

[Vetter]

You land the T-38 in a crab...there is actually no last second aligning with the runway. Once you have landed, you use aileron into the wind and opposite rudder the maintain centerline. From the backseat in the -38, I love having crosswinds because I can actually see the runway I'm landing on, especially during a no-flapper.

[Guest Tigerpilot]

Originally posted by flyinjunky:

The tweet would slip ok, but like everyone said, it's considered poor form.

Correct me if I'm wrong, but in the tweet we're taught to fly with X-wind controls on final (opposite rudder and aileron), which is uncoordinated flight, in order to keep the nose tracking straight down the runway and prevent side loads on the landing gear. Otherwise every IP I have in UPT has been teaching it wrong.

[BFM this]

Originally posted by rotorhead:

...so my question is, how the heck do you land a tweet WITHOUT cross-controlling it in a crosswind?

OK, I didn't complete that thought very well. In the tweet, yes, you would cross control for x-wind landings to line up the wheels/flight path/runway all same way-same day. You don't, however, roll out on a 5.5 degree final and say to your instructor "hey, watch me fix this" while you stomp a boot full of rudder against opp aileron.

In the -38, the slip indicator stays in the center even if you are looking across the rwy in our limiting 25 kt xwind.

[Baseops.Net]

As pointed out - there are several types of Slips, etc. I am no aero engineer (legal disclaimer).

What the question is (I think) is whether or not in UPT (or elsewhere in the USAF) during your final turn you can/should kick in some bottom rudder to *help* you around the turn. And/or on straight-in final and you find yourself high and fast you throw in some strong cross-controls (again kicking in some good rudder) to slip your way down.

I can say as a turboprop air force guy... NO.

I don't think we are discussing the merits of the "wing low method" for x-wind landings!

Again, let me say that it is a technique that many a student uses to try and *save* a bad approach / pattern that should be waived off instead.

However, I don't doubt that there may be a demo item or introduce item that shows a stud how to slip, etc. But I know that your book doesn't include the slip as one of the steps in performing a normal landing.

[Guest rotorhead]

flyinjunky-no worries, I kinda thought that's what was going on here...the original post by piperpilot and the responses should be clear:

there is enroute descent, approach, and touchdown. I read the word "landing" in the original post as "touchdown" while many others read it as "approach"...piperpilot, did you want to clarify the question?

[Guest rlb]

"What the question is (I think) is whether or not in UPT (or elsewhere in the USAF) during your final turn you can/should kick in some bottom rudder to *help* you around the turn."

I would definitely recommend NOT using bottom rudder to slip in the turn to final (this is a great way to spin an airplane). Top rudder however is perfectly safe in a single engine civilian plane and a T-6 for that matter. I imagine the AF dosn't want T-6 studs slipping in the pattern because it could kill them in their future jet.

[BFM this]

I don't know of anywhere that ruddering around a turn or slipping in a turn is taught. In fact, coordinated pattern turns are emphasized in civil primary (mil also) to avoid the base-final stall/spin.

Beyond that, it is something I have used in a no-flap plane like a Citabria or Champ if I can see a high glidepath develop while still on base leg. In essense, I keep the wings level while using the rudder to turn the plane. At that point it's nothing more than a forward slip with the lift vector pushed off center, giving a horizontal component to turn the plane. I'm lobster-eyeing the airspeed pretty close (as I would in any slip) and it's definately not something I'd teach to a primary stud for the aforementioned reasons.

Back to the original question: NOPE, wouldn't do it in a mil jet--that's what we practice go arounds for.

[ 21. February 2005, 13:20: Message edited by: flyinjunky ]

[Guest Tigerpilot]

I got what y'all are saying now. I guess I was just making sure the notion that cross controls on final wasn't wrong (at least in the tweet). Our instructors at ENJJPT definitely do emphasize the fact that we'll probably never use the rudder again and not to get into the habit of using it all that often because it will create huge issues in a few months when we get to 38s and beyond.

[Riddller]

We used wing-down-top-rudder all the time landing the Herk, and once with a 40kt crosswind (Lajes, nowhere else to go) we used a BUTTload of assymetric thrust... work good, last long time!!

The only time I saw a slip used in a Herk to lose altitude, we were in holding at 17,000ft over DFW 'cuz of bad Wx, and ATC asked us to "expedite" a descent down to 11,000ft, so the AC (the Squadron CO at the time) yelled for everyone to hold on and slammed the left rudder to the floor and dumped the nose. Needless to say, we 'expedited' the descent!!!

[ 21. February 2005, 13:36: Message edited by: Riddller ]

[Guest Piperpilot2004]

yeah sorry for the confusion. I should have been more clear with my question. I think it was answered, but what I meant was- on final are you guys aloud to do a side slip if you are above the glide path? I think it was answered thanks! A couple people wanted me to clarify-