Side-slipping the Jabiru

[moy71]

When side-slipping the Jabiru aircraft on approach, does the nosewheel move in conjuction with the rudder?

 

Or perhaps the nosewheel moves independantly of the rudder in flight?

 

Why I ask is this: in a Left-to-right crosswind situation (using side-slip approach), the pilot would hold the left wing down and kick the right rudder to align the plane to the runway. Is the right rudder RELEASED to the neutral position just before touchdown of the nosewheel or is it released gradually?

 

I am confused as to how the nosewheel would react if the pilot needs full right rudder on approach (remember sideslip) to maintain alignment and if he touches down in this position, would there be a tendency for the plane to loop to the right since it has touched down in the full right rudder position?

 

I think I read somewhere that Cessnas have a mechanism that separates the wheel steering function from the rudder in flight. In other words when the right rudder is kicked in flight, the nosewheel REMAINS in the neutral position. Can anyone confirm this?

 

 

[Guest Brett Campany]

As far as I know, all jab's with nose wheel steering will turn as you use the rudder, so yeah, it'll move alright!

 

 

[Guest mike_perth]

I fly a Tomahawk and Im fairly certain that the nose wheel is certainly doing the same as the rudder in all stages of flight as in a cross wind take off I have heard to front wheel squeel slightly on rotation just as more rudder is required (due to less weight on nose wheel) so Im assuming would be the same for landing - Another good reason to hold that nose wheel off on landing!

 

 

[Derby]

Hi Moy, you are right you must kick the rudder straight before you lower the nose wheel down or you will shoot off one way or the other. It's not that hard.

 

Rory

 

 

[seb7701]

As the others have just indicated, you should have straightened up just before touchdown anyway, otherwise I would imagine that you would risk ripping you landing gear of if you were to land whilst still in a crabbed configuration.

 

As was also mentioned, your nose wheel definately shouldn't be touching the ground until you have straightened things up.

 

 

[Gibbo]

Nose wheel steering and rudder are connected and you need the nose pointing directly down the strip before touchdown.

 

Gibbo

 

 

[Guest Maj Millard]

Yes, on some GA single engine aircraft, the nose wheel steering become disconnected when the aircraft is off the ground. This is done pretty simply, and is activated by the extended (hanging) nose strut.

 

After touchdown, with weight back on the strut (strut now compressed) steering is again activated.

 

Best example of a negative side of this is on the Cessna 206. When fully loaded and tail real low, the nose strut becomes over extended, and steering becomes difficult. It then requires use of differential brakeing to taxi...................

 

 

[Skyhog]

Best example of a negative side of this is on the Cessna 206. When fully loaded and tail real low, the nose strut becomes over extended, and steering becomes difficult. It then requires use of differential brakeing to taxi...................

Same as the C182E I have been doing parachute ops in recently.Pilot plus 5 jumpers makes a 182 look like a 180/185 whilst taxiing.Brakes are definately required to turn!!

It's funny...over the time I jumped out of planes over 2500 times,when the pilot was concerned over something we would just tell him just get us to height "you'll be right mate".When you're in charge it's a bit different.

 

 

[Seal]

As the others have just indicated, you should have straightened up just before touchdown anyway, otherwise I would imagine that you would risk ripping you landing gear of if you were to land whilst still in a crabbed configuration. As was also mentioned, your nose wheel definately shouldn't be touching the ground until you have straightened things up.

That sort of misses the point a bit though. If you are landing in a crosswind with a sideslip approach then you will have the into wind wing down with opposite rudder and the thing will be pointing, and traveling, straight down the strip so the straightening up bit does not apply and, if everything goes according to plan, there is no undue strain on the gear.

 

The interesting bit comes when you lose elevator authority and the nosewheel lowers onto the runway. If you are in a Jab then the nosewheel is definitely connected to the rudder all the time and the wheel will be pointing to steer in the same direction as the rudder, ie turn away from the wind, so if you just drop the nose and leave everything the same then the thing will swerve towards the down wind side of the strip. That makes sense if you remember we are in a crosswind. Before we lowered the nose the thing was trying to weathercock into wind and we were using rudder to hold the nose out of the wind.

 

The trick is to remember that when we can no longer hold the nose up airspeed has decayed, the rudder become less effective and steering authority transfers from the rudder to the nosewheel and we need to position the pedals to steer the thing straight so, as the nose lowers we smartly take off the rudder and steer straight down the strip. With a little bit of practice you get the timing right and the transition happens seamlessly.

 

 

[moy71]

To add more confusion to myself, I've read somewhere that others do a FORWARD-SLIP instead of a side-slip. Is this the same manoeuver or different?

 

 

[skybum]

Moy71, yep the forward slip is a sideslip. Your technique should change from crab to forward slip just before you flare. With forward slip technique you are aligning the nose wheel with the runway and using the ailerons to stear to keep aligned with the centreline.

 

The kick works as well but why bother, you haven't the need to keep engine pods clear of the black top.

 

 

[Aussie Steve]

As far as the LSA55 goes, It does ""not"" say in the Pilots Ops Hand Book that its ok to sideslip the aircraft. ! Another one of Jabs silent omissions.

 

 

 

The vert stab is very light and almost flimsy,give it a little jiggle next pre flight.You should be looking for cracks around its base especially if other users are sideslipping regulary.

 

 

 

I,d hate to have a failure at that critical stage on finals.

 

 

 

[Modest Pilot]

Caution: This applies to my J230D. After gathering up 100 hours on type decided to explore the envelope a little. You can land wing down 15deg nose yawed by the same amount or combinations of same; and although I wouldn’t suggest slamming the nose hard down on touch down; the aircraft kicks straight by itself without problems. The limit on x-winds shows up later in the roll out, without toe brakes and no differential braking the aircraft rounds up into wind, hence the 14kn limit I suspect. Also the ailerons are pretty weak at low speeds, with really rough conditions I settle on 70-75kn on approach and cheat a bit using rudder to help out on roll rate. Not ideal but that’s life!

 

 

 

[poteroo]

US pilots refer to a forward slip as one where the nose is aligned away from the runway, and the wing is lowered toward the runway - which tracks you down the centreline. Purpose?.... to increase rate-of-descent, but give yourself some height to recover to unslipped flight. If you keep the nose into wind, then the remaining approach - from 200 ft onwards, can be flown using a normal crabbing technique.

 

A sideslip is therefore where you hold the nose aligned with the runway or other ground feature, and lower the into wind wing so that you slip into wind, and so track along that runway line. If you are pushed downwind by a change - then you can sideslip more aggressively to regain your desired alignment. Yes, this also increases your R-O-D, so you need a bit more airspeed as you start, or carry a little power.

 

The limiting airframe feature is usually the rudder, which in most sweptback tails, loses effect before your ailerons. Wonderful round ruddered aircraft like Cessna 170's,and Cessna 180's with big vertical rudders, can usually be slipped to the limit of the ailerons 1st.

 

The J160 comes down fast enough that forward slipping isn't usually necessary, although we do teach it's limited use for approaches. For side-slipping in crosswinds, we've found that you can run out of rudder command, but holding on a few 100 RPM into the flare does give you much more control.

 

happy days,

 

 

[moy71]

that's an excellent layman's explanation which i can understand easily. Thank you!