Side slipping (video)

[aro]

Avoid is very different to "not permitted".

 

e.g. "When flying in the outback, avoid flying during the hottest part of the day."

 

or in the context of a 172 POH:

 

"Abrupt use of the controls is prohibited above 98 knots"

 

and

 

"In the execution of all maneuvers, avoid abrupt use of controls"

 

 

[facthunter]

Not very convincing... Words are different. Effect isn't in an aviation sense. Nev

 

 

[aro]

There is a distinct difference.

 

"In the execution of all maneuvers, avoid abrupt use of controls" applies always, but doesn't prohibit abrupt use of controls. People do use controls abruptly from time to time, it's OK if the speed isn't excessive, but yes it should be avoided.

 

"Abrupt use of the controls is prohibited above 98 knots" prohibits abrupt use of controls above manoeuvring speed.

 

The distinction between above and below manoeuvring speed is obviously very important.

 

It's not just an academic discussion when referring to flaps:

 

C172 VFE is 85 knots "Do not exceed this speed with flaps down" (10-30 degrees) - i.e. prohibited

 

Avoid slips with flaps - avoid, not prohibited.

 

If you are too high in a forced landing and need to lose height, you might be making a choice between slipping with flaps out and exceeding VFE. The difference is important - "avoid" means it is not expected to damage the aircraft, whereas exceeding VFE could cause structural damage or failure. If you treat both as equally prohibited people are likely to pick the wrong answer and just push forward past VFE.

 

In any case, how do you do a crosswind landing without a slip? The crosswind landing section refers to using flaps during sideslips with full rudder deflection, so it obviously is permitted.

 

 

[Camel]

There is a distinct difference."In the execution of all maneuvers, avoid abrupt use of controls" applies always, but doesn't prohibit abrupt use of controls. People do use controls abruptly from time to time, it's OK if the speed isn't excessive, but yes it should be avoided.

"Abrupt use of the controls is prohibited above 98 knots" prohibits abrupt use of controls above manoeuvring speed.

 

The distinction between above and below manoeuvring speed is obviously very important.

 

It's not just an academic discussion when referring to flaps:

 

C172 VFE is 85 knots "Do not exceed this speed with flaps down" (10-30 degrees) - i.e. prohibited

 

Avoid slips with flaps - avoid, not prohibited.

 

If you are too high in a forced landing and need to lose height, you might be making a choice between slipping with flaps out and exceeding VFE. The difference is important - "avoid" means it is not expected to damage the aircraft, whereas exceeding VFE could cause structural damage or failure. If you treat both as equally prohibited people are likely to pick the wrong answer and just push forward past VFE.

 

In any case, how do you do a crosswind landing without a slip? The crosswind landing section refers to using flaps during sideslips with full rudder deflection, so it obviously is permitted.

When 40 deg of flap extended on a c172 N I do not believe it is possible to exceed VFE ! I'll stand to be corrected but I couldn't do it and tried !!!!!

 

 

[facthunter]

Most of the damage was done by extending the flaps above Vfe. It would buckle the upper surface of the wings. More likely on the bigger hi wing Cessna's where you are cruising a bit faster. Nev

 

 

[Nobody]

I stand to be corrected but I think that early 172 models have 40 degree flaps and later ones 30 degree flaps. With 40 degree flaps in a go around situation the climb rate was pretty bad to the extent that this was the limiting criteria for MTOW. Someone other than Cessna designed an STC that would reduce the flaps extension to 30 degree and increase the MTOW. Cessna then incorporated that change into later models.

 

 

[facthunter]

The C-172 is NOT overpowered. It's really a 3 seater. Wouldn't get far with full flap extended to 40 degrees. Nev

 

 

[Nightmare]

I remember doing a heap of side slipping when I was training.

Same here, and I still do. It's a great way to loose height with full flaps, without increasing your speed. As long as you keep that speed up at your approach speed and it's ok by the POH.

[SilverWing]

For info - Foxbat sideslip

 

 

 

[DrZoos]

Love them, do them virtually every flight, just be careful to stay within speed for your aircraft, read your manual and if in doubt ask an instructor.

 

 

[David Isaac]

Fox bat slips beautifully;

 

The Citabria comes down like an elevator with full flap and an aggressive slip;

 

The Auster likewise at 45 knots IAS or higher if you are chicken.

 

Ive slipped the Cessnas, but it is a waste of time. If you have the earlier 40 degree flap models; just push the nose down and the drag is so high they sink like an elevator and don't accelerate that much and when you round out the speed drops off real quick. IMHO they ruined the C models when they STC'd the flaps back to 30.

 

 

[facthunter]

IF you have an unflapped plane, it's rather necessary to be able to slip capably then you can keep your circuits tight and be a little high and slip it off. Get used to landing on one wheel in crosswinds too. Some students don't like this but get used to it.. It's all part of the same technique. You will find you PREFER one direction over the other. I prefer to have the left wing down moreso than the other way but practice both ways as the wind direction dictates what you must do, not what you like. Nev

 

 

[MikeBravoYanky]

Nothing slips quite like a cub.

 

So my SupaPup should be ok with side slips..

 

 

[MikeBravoYanky]

IF you have an unflapped plane, it's rather necessary to be able to slip capably then you can keep your circuits tight and be a little high and slip it off. Get used to landing on one wheel in crosswinds too. Some students don't like this but get used to it.. It's all part of the same technique. You will find you PREFER one direction over the other. I prefer to have the left wing down moreso than the other way but practice both ways as the wind direction dictates what you must do, not what you like. Nev

I know a Tiger Moth pilot who said side slips were hazardous and had apparently seen one go into some sort of unrecoverable slip.. if so what's the problem..?

 

 

[Nightmare]

I know a Tiger Moth pilot who said side slips were hazardous and had apparently seen one go into some sort of unrecoverable slip.. if so what's the problem..?

Sideslips put the aircraft in an unbalanced state, therefore increasing drag and the stall speed. However, as your approach speed is generally well above stall, you can do this quite safely, for the benefit of a higher descent rate without adjusting your speed. As others have said here, check the POH to see if sideslips are ok, as there may be structural issues with doing them.When I was doing my training, I was taught it is hazardous to do a sideslip in a turn, those 2 conditions increasing the stall speed. My guess is that Tiger Moths don't have flaps so therefore, I would've thought sideslipping would be a big part of the operation of this aircraft. If the speed isn't managed carefully, a stall in a sideslip could occur slightly higher that the rated stall speed. A rather nasty possibility when you stall during a sideslip, is a wingdrop....

 

 

[facthunter]

I've done plenty of slips in a DH 82 and can't see what any problem would be. They slip rather well . As far as an "uncontrollable slip" I can't imagine what they are talking about or why it would happen. The plane has to be held into the slip. If you released the aileron and centred the rudder it comes straight out of it. With a plane like the Wright Flyer, which has no keel surface , It can slip into the ground sideways without rudder application to turn towards the down wing. THAT would be a little counterintuitive to the normal picking up wing with rudder. Nev

 

 

[facthunter]

Airspeed in a slip is pretty critical. The instrument may read incorrectly due pitot location, and the "new" relative airflow. If you have the airspeed too high you are loading up the airframe and it doesn't feel as nice. If you get too slow with controls crossed you are set up for something to happen and it's usually a roll over the top at low airspeed, which you would want to do something about rather quickly. When you are learning it's "normal" to finish your slips at a reasonable height, say 150 feet but later when you are more comfortable you continue them to the flare. (If you are really on top of it). This is not for the "low hours" pilot as the potential for getting out of shape is very much there. In my observations, people doing slips well is rare. Even IF you once did them well, it needs recent practice to a level few get and each plane has it's own idiosynchrasies. Slipping to counter drift is much easier. Much less extreme. Most passengers don't like sideslips, either. nev

 

 

[DrZoos]

https://www.youtube.com/watch?v=FZJw9moCne0

 

Also see page 7 & 11

 

doesnt negate need to check POH, but seems they do them in Tmoths

 

http://www.tigermothclub.co.nz/wp-content/uploads/2012/09/aerobatics-dp.pdf

 

and

 

http://www.dutchfs.com/crew/leen/Tiger.pdf

 

page 7

 

 

[Roundsounds]

As mentioned by someone earlier, entry into a side slip is normally effected by banking with aileron and preventing the turn with rudder - in that order. It looks like the reverse order was used here, yet no comment by the instructor?

 

https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-4of7.pdf

 

Refer page 8-10

 

The radio call by the instructor following the simulated engine failure was of little value, "glide approach 28" - but from where? Base, overhead, mid downwind and was this for a full stop or touch and go? Also the habit of keying the mic to acknowledge the Bonanza's inbound call is annoying at best and proves nothing.

 

 

[facthunter]

I had to run that vid 3 times to detect the "sideslip". Watch the rudder closely. When you do a sideslip there is no difficulty detecting it. A wheeler Landing is so much faster. The "normal" landing was always a 3 pointer. The basic Tiger Moth has no brakes so it rolls pretty freely till the tailskid reaches the ground. Because the steerable skid has a ridge running along it, it steers better (on grass) but does some damage to the surface and many are fitted with brakes the wheels moved forward and a tailwheel installed. the more forward placed wheels make the plane less stable directionally than the original. Nev

 

 

[Parkway]

I had heard ppl say don't side slip a Cessna with full flaps because you lose authority in the rudder and elevator due to the flaps being such big barn doors hanging down blocking the air flow

 

 

[Old Koreelah]

I was once told to not slip with flaps extended. Haven't found anything to explain why.

 

 

[David Isaac]

I had heard ppl say don't side slip a Cessna with full flaps because you lose authority in the rudder and elevator due to the flaps being such big barn doors hanging down blocking the air flow

Not true buddy, however if you are talking about a 150 or 172 still with the 40 degree flaps fitted, side slipping is less effective because the rudder doesn't have enough authority to hold the aircraft in a significant slip. You will never run out of elevator authority in any Cessna I have flown. I'd imagine the ones with the STC reducing flaps to 30 degrees might slip better, just haven't tried. In any case when you have 40 degrees of flap on a Cessna, you don't need to sideslip, just point the nose down steep and stay within the white arc (pretty hard to exceed with the barn doors down), and you will go downhill like an elevator and when you round out, the drag is so high the speed reduces very quickly.

I was once told to not slip with flaps extended. Haven't found anything to explain why.

Not so Lyell, but always read the POH. The Citabria and Auster slip beautifully with flap down. It just gives an extra dimension to sink rate

[djpacro]

Suggest that you read earlier posts in this thread for discussion re wots in the POH about sideslipping the 172s ...

 

 

[David Isaac]

Suggest that you read earlier posts in this thread for discussion re wots in the POH about sideslipping the 172s ...

I guess I better ... LOL. All I know from experience under instruction is that side slipping a 150 or 172 with 40 down is a waste of time and diving is more effective.