Pitts Spinning

[djpacro]

Specifically the Model S-2A.

 

The Pitts has featured in my other posts on spinning so I thought that it should have its own thread as well.

 

The Flight Manual doesn't say much about spinning, in common with other manuals from the early '70s and earlier:

 

For spin recovery put ailerons neutral, apply full opposite rudder briskly and then apply nose down elevator. Use power off for all spin recoveries.For flat spins use aileron wih the spin for recovery

It doesn't give any guidance on how much nose down elevator and we know from those other articles that full forward stick can result in a cross over to an inverted spin.

It also doesn't say anything about inverted spins.

 

We have seen what is meant by "aileron with the spin" for both upright and inverted spins.

 

We've seen from Mueller and Beggs that their simple emergency spin recovery technique works well. We've had Bill tell us that his even more simple F.A.R.T. works well too.

 

Anyone flying a Pitts must be fully familiar with all of its spin modes - both upright and inverted. You may have seen some other threads where its habit of suddenly entering an inverted flat spin from a failed aerobatic manoeuvre is graphically explained.

 

 

[djpacro]

Eagle Spin

 

The Aviat (originally called the Christen) Eagle II has a full seven pages about spinning! As the Eagle is very much like a Pitts S-2A I always recommend that Pitts pilots familiarise themselves with this document. Aviat still offers the Eagle II kits as well as its line of certified aircraft including the Pitts S-2C.

 

Let's have a look at a few extracts from the Eagle manual (minus the excellent diagrams):

 

The Eagle II aircraft has docile and controllable stall characteristics with no tendency to spin; however the aircraft will spin immediately and well if the proper control inputs are made following a stall..... Accidental spins resulting from maneuvering errors can be of any of the four possible spin types.

All theoretical explanations and all procedures in this section should be studied to develop thorough understanding. All procedures should be memorized and then rehearsed in the aircraft on the ground. Spin recovery procedures must be practiced in flight so that if and when any procedure is required, it can be performed instinctively and unerringly.

 

Inexperienced aerobatic pilots, in particular, must be extremely careful in learning spin recovery procedures. Although spin recovery procedures will become simple, automatic responses when mastered, do not assume that previous flying experience plus limited study will suffice.

 

…..

 

Throughout the following text, relative directions are given from the pilot's viewpoint. For example, an inverted spin to the right is toward the pilot's right, even though an exterior observer might think of the spin as a being a “left-hand spiral” or 'toward the left”.

 

Spin direction is always considered to be the direction of yaw, so a spin to the right can also be described as a right-rudder spin …

 

Rudder input which tends to stop the yaw during a spin is called “opposite rudder”. ….

 

Because aircraft attitudes, relative directions, and control inputs can be confusing when studying spins, use a model airplane to represent spin conditions while reading ….

 

All spin types include two essential and fundamental characteristics: 91) the wings are stalled and (2) the airplane yaws continuously. ….

 

…...

 

By making use of inherent aerodynamic stability, the Christen eagle II will recover from normal upright spins, normal inverted spins, and flat inverted spins simply by (a) cutting engine power and (b) neutralizing the stick and rudder pedals. The application of this procedure is explained further

 

…...

 

In the case of a flat upright spin when the aircraft is loaded to produce a CG near the aft limit, power reduction and neutral controls are insufficient; the proper recovery procedures in paragraph 5-8, must be used.

 

….

 

Application of power increases the difficulty of spin recovery.

 

….

 

For inexperienced aerobatic pilots, as well as experienced pilots who are unfamiliar with the spin characteristics of the particular aircraft type, inadvertent and unanticipated spins may produce a dangerous sequence of events. Sever disorientation is caused by the spins and by the previous maneuver which produced the spin. The spin type then becomes extremely difficult to identify and therefore produces uncertainty as to the correct recovery procedure. The pilot may then, in panic, conclude that the only approach is to experiment haphazardly with various control inputs, hoping to discover the correct combination for fast recovery.

 

A primary problem in spin recovery is failure of the pilot to identify the true spin type followed by application of erroneous control forces that hold the aircraft in the spin.

 

…....

 

if violent control inputs for recovery from a normal upright spin are made … the aircraft will recover from the first spin and immediately transition to a normal inverted spin with reversed rotation.

 

….

 

Many pilots erroneously consider the spin to be a rolling maneuver, ALL SPINS ARE YAW MANEUVERS, AND RUDDER IS THE ESSENTIAL CONTROL. The spiralling-type roll associated with a spin is secondary, and pilots must guard against any temptation to “roll out” of a spin using ailerons.

 

…..

 

Any aileron input that is opposite to the direction of spin yaw tends to flatten the spin and makes the spin worse (more difficult recovery). .. during an upright spin the spin will tend to faltten with stick away from the spin axis and in an inverted spin the spin will tend to flatten with stick toward the spin axis.

 

….

 

A serious problem in perception of spin direction can result if pilot attention is directed, perhaps unconsciously, to roll direction.

 

….

 

The frequent correspondence of yaw and roll may cause the pilot to unwillingly equate yaw direction with roll direction. However, IN INVERTED SPINS, YAW AND ROLL DIRECTIONS ARE OPPOSITE.

 

…...

 

recovery problems are easily compounded by combinations of limited pilot experience, possible overconfidence, sever disorientation in the spin, reaction to sensory miscues, and failure to recognise recovery, followed by re-entry into another spin type.

 

….

 

If the spin is known to be a normal upright spin, the standard recovery procedure, which places the aircraft in a steep dive, is as follows:

 

1. Pull the throttle full aft to cut engine power.
    
    
   
2. Push the rudder pedal gently but firmly in the direction opposite the spin to stop yaw.
    
    
   

 

….

 

1. Push the control stick gently but firmly forward to unsatll the wings.
    
    
   

 

…...

 

If the spin is known to be a flat upright spin to the left, the standard recovery procedure, which basically places the aircraft into a normal upright spin, is as follows:

 

1. Pull the throttle full aft to cut engine power
    
    
   
2. Move the stick full left (that is, toward the spin axis and in the yaw direction), to force the inside wing down
    
    
   
3. Hold the controls until a normal upright spin has developed (½ to 3 turns, typically less than 1 turn) and then recover from a normal upright spin using moderate forward stick and moderate right rudder .. These control inputs are typically introduced at the same time as aileron deflection, producing a smooth single-motion recovery.
    
    
   

 

…..

 

If the spin is known to be a normal inverted spin …

 

1. Pull the throttle full aft to cut engine power.
    
    
   
2. Push the rudder pedal gently but firmly in the direction opposite the spin.
    
    
   

 

….

 

1. Pull the control stick gently but firmly aft.
    
    
   

 

….

 

Excess or violent … may cause the aircraft to transition to an upright type spin.

 

…..

 

If the spin is known to be a flat inverted spin to the right, the standard recovery procedure …

 

1. Pull the throttle full aft to cut engine power.
    
    
   
2. Move the stick full left (that is, toward the outside of the spin, away from the spoin axis), to force the inside wing down.
    
    
   
3. Hold the controls until a normal inverted spin has developed …....
    
    
   

Whew! Its a lot easier to use BM isn't it.

Note the use of the word "immediately" in that manual - it means "instantly".

 

 

[fly_tornado]

some complex spin recovery techniques

 

[media=vimeo]18779293[/media]

 

 

[Flying Ant]

Dave, how much height is typically lost in a normal power off upright spin in a Pitts? Say 1 turn... open question I know

 

 

[djpacro]

Ant, my typical briefing is to allow 800 ft for operations with minimum altitude of 3,000 ft AGL.

 

 

[DanGriffith]

Could anybody let me have the full seven pages of the Eagle spinning, please, as I am just about to do a spin program on the aircraft. Thanks

 

 

[djpacro]

Enjoy!

 

eaglespin.pdf

 

eaglespin.pdf

 

eaglespin.pdf

[DanGriffith]

Hi DJP

 

Fantastic - many thanks! I'll let you know how it goes!

 

 

[djpacro]

Have fun!

 

An interesting magazine article by a friend in a friend's Eagle which was built by another friend - a nice airplane - Flight Test: Christen Eagle

 

 

[DanGriffith]

Many thanks - I'll take a look.

 

ATB

 

Dan

 

 

[rideandfly]

DJP,

 

New member here. Thanks for the excellent spin information.

 

Purchased an Aerobat years ago and received spin/aerobatic training for flying basic aerobatics in the Aerobat.

 

Going through positive G spin/aerobatic training with Bill Kershner in his Cessna Aerobat years ago. After 10 to 12 turns during the spin, engine would stop running due to centrifugal force un-porting fuel pickups in the wing tanks, the propeller would stop windmilling, too. Very quiet! We recovered after 21 turns.  Bill liked to joke saying before re-start, open the window and holler "clear prop"!  The Aerobat would lock into the spin and the Beggs/Mueller spin recovery technique would not work. Bill taught me to always use the NASA recovery technique in the Aerobat.

 

Received a little spin training with Bill Finagin years ago in a S-2C.  We started out with a positive G spins, transitioned with full forward stick/opposite rudder into a negative G spin, transitioned back again to Positive G spin with full back stick/opposite rudder. Did two or three sets of spins like this, it was a blur. Made recoveries in the Positive G spin using the NASA/PARE technique that Kershner taught me.

 

The Pitts is loads of fun to fly!!!!

 

Bill

 

 

[Area-51]

Just spent five hours in an S2-A stall spin entry recovery training.

 

Regardless of any 16 spin variations - Ailerons centralised, power back to idle, full immediate opposite rudder, unload the elevator, immediately centralise the rudder back to neutral, upon end of autorotation throttle up smoothly to full power, then immediately pull out with maximum affective elevator to climb attitude, wings level, ball centred with left rudder bias....

 

Duration of recovery procedure is approximately three seconds.... lazy rudder centralising action may initiate and result in an entry into opposite direction spin.

 

Truly is the ultimate Sky Machine.

Edited September 22, 2022 by Area-51

[djpacro]

1 hour ago, Area-51 said:Regardless of any 16 spin variations - Ailerons centralised …

The factory test pilot found some modes which were not recoverable with that method. Amendment to the AFM and cockpit placard refers.

[Bosi72]

12 hours ago, djpacro said:

The factory test pilot found some modes which were not recoverable with that method. Amendment to the AFM and cockpit placard refers.

Hi DJP 

Are you referring to flat spins?

Thanks 

 

 

 

 

 

 

[djpacro]

6 hours ago, Bosi72 said:

Hi DJP 

Are you referring to flat spins?

Thanks 

Yes, that is the placard (although not actually required for all flat spins, testing revealed specific control actions to get it there).

 

Interesting that the general spin placard there is not quite correct per the AFM.