Posted for "ckohler1@cfl.rr.com" <ckohler1@cfl.rr.com>:

 Sorry it took so long to answer but I'm on the road and not online everyday.
 A lot the article is here and a part of Mark Kirchner's post is also
 included.
 
 Charlie K.
 
 STALLS/ SPINS (LIV)

 NEVER-NEVER practice approach to stalls with passengers in the back seats, any cargo in the baggage compartment. The Lancair IV will normally give very little warning (buffet) when approaching the stall.  It tends to have a right "wing-drop" in a stall. Recovery might require substantial altitude. Therefore, I recommend the wing should have stall strips installed to give an additional buffet warning, and prevent excessive" wing-drop". The aircraft wing loading is high (L-IV is 32- 34 #/sq.ft.).  An incipient stall entry will require more altitude for recovery than is available during final approach. Therefore, provide adequate speed margins during final approach. The aircraft buffet warning if speed margin is violated and stall condition is approached.
If, during the banked turn to final approach, slowing to follow slower traffic, distractions due to weather, traffic, or whatever, result in the pilot pulling excess "g's" during the turn, then the stall angle of attack can be reached even while you are still maintaining the target approach speed. Of course, a combination of factors -- such as drifting below target approach speed due to the same distractions - can amplify this risk. Therefore, a means to provide a warning of the approach to a stall angle-of-attack -- independent of the maintenance of accepted speed margins - is desired. Again, the added warning of wing-buffet is desired.
Adding wing "stall strips" to the inboard leading edge of the wing works on both the "wing-drop" problem and the objective of developing wing-buffet warning.

WING STALL-STRIPS
The strips are triangular in cross-section with about a 9/16" base attached to the wing and 3/8" sides leading to the leading edge apex. The center-line of the strips met the leading edge of the wing about 0.2" below the leading edge vertical tangency plane intersection. (This is the vertical orientation originally suggested by Martin Hollman). The idea, of course, is that the apex of the stall strip be placed as closely as possible to the airfoil cruise stagnation point (so there is no cruise drag created), but still allowing stall initiation at high angles of attack. Strips on both wings; 8-10" long starting 18" out from the side-of-body. I decided to go for both wings to help promote balanced stall regardless of power effects or unsymmetrical flight effects.
The buffet speed margin and the strength of the buffet will vary with power setting and flap setting. A range of approximately 3 knots to 6 knots buffet speed margin will be experienced. The initial stall break is balanced without wing drop.  I do not recommend that the airplane be tested beyond initial stall break. The increase in stall speed due to the stall strips was small and difficult to measure -- so an approximate guess is 1 to 2 knots. The same is true with respect to the effect upon cruise speed at a given power. It is difficult to measure any change in cruise; this implies that the vertical location of the stall strip at the leading edge is close to optimum.
Finally, I would advise that any testing ( even simple approach-to-stall testing) be conducted at 10,000 feet AGL or higher.

FRANTZ AOA (Angle-of-Attack) INSTRUMENT
There are two major benefits for using an AOA instrument to provide stall margin compared to simply using airspeed. First, at one "g" flight, the stall airspeed varies with the square-root of aircraft weight; therefore, if a constant (average) target landing-approach airspeed is used, it is only an approximation for very heavy or very light weights. Secondly, at a given airspeed (which may be chosen to provide adequate stall margin at one "g"), the margin diminishes rapidly in a turn -- without any indication to the pilot as to the extent.
The AOA instrument allows you to index the desired margins with respect to wing angle-of-attack, and the margins stay the same regardless of weight. And, for a given airspeed, the "g-effect" is automatically included in the display (and aural warnings). One can select different margins for different flap settings. The example numbers are for a typical landing weight of 2900 Ibs. (2250 Basic + 2 men + 45-50 gal. fuel), For other landing weights the airspeeds would vary as the square root of the weight (for the same AOA reading).

At 12" Man. Press. Full flaps: 2900 lbs. weight, gear down.

Target Vapp. 1g Aural Warning 1g Light Buffet 1g Stall Break
99 knots     84 knots    70 knots      65 knots
(1.52 Vs)    (1.29Vs)   (1.07 Vs)      (1.0 Vs)

Several comments:
Those who have experience flying heavy transports may know that their published approach speeds are 1.3Vs (compared to my 1.52Vs, above). However, the factors that govern the requirements for margins tend to favor equivalent incremental speed margins rather than equivalent speed ratio margins. Thus, the lower speed aircraft needs a higher speed ratio margin than the higher speed aircraft. The 99 knot approach speed (for the average landing weight shown) is essentially the same as the 100 knot approach speed advocated in training.  For a light landing weight of 2600 lbs, the Vapp would be 94 knots; for a heavy landing weight of 3200 lbs, the Vapp. would be 104 knots.

At the target approach speed, the Aural Warning would sound at 1.38 g.

The AOA instrument has one other feature that should be noted. It has an Aural Warning at an absolute speed (not angle-of-attack) for "Gear Down". This can be set at any speed. I have mine set at 110 knots. I fly a target speed of 120 knots on instrument landing patterns (15 in. 2500 RPM, Half-flaps gear-up). If I drift down to 110 knots, I get a gear-down aural warning --- which, since I am slow, means I have probably crept up in altitude from my target pattern altitude.

A theory on why the aircraft has a right-wing-drop at initial stall break: The propwash provides an incremental upwash on the left wing and downwash on the right wing. However, this is concentrated primarily on the inboard part of each wing. In order to balance this, a small amount of down-aileron on the right (and up-aileron on the left) is flown. Although a down-aileron wing section (like a flapped wing) stalls at a higher total lift, it does so at a lower wing section angle of attack than does an up-aileron wing section. Thus the right wing stalls first, providing the wing drop.

If all goes wrong, and the aircraft enters a spin while practicing approach to stalls, here are the techniques to recover.

  A good way to enter a FLAT SPIN is to use the wrong order of steps in the recovery of a normal upright spin. Also, of course, the all important "aft C-G" result of improper baggage loading, is the primary culprit. And, structural damage to the aircraft in flight can also contribute to flat spins, etc.
Remember: Aft C-G is usually the big offender. It causes a "flatter" spin. In even a normal upright spin, such aft c-g can delay-- or make impossible a recovery. It causes a more complete stall ! Also, remember, that the flat spin always transitions from a normal spin, thus the recovery is a transition from a flat to a normal spin before recovery steps can be completed. Recommended recovery steps are:

Power off. (This helps get the nose down into a normal spin)
Remove hands from the elevator control. This lets ailerons center, if any is
            being applied AND allows the nose to drop, stopping the stall.
POSITIVE full rudder opposite to spin to stop rotation.
Then, neutralize rudder and pull out of spin minding not to pull too many                                  G’s. Remember, if rudder is held too long, you could continue a spin in the reverse     direction. Do not use ailerons on entry or exit.

By simply using the wrong order of steps in your recovery of a normal upright spin you can get yourself into such difficulty that it could be impossible to correct. Remember the correct steps:
1. Power off
2. Full opposite rudder
3. Forward on stick

You may not have all your composure when you find yourself in an unexpected spin and thus, get the recovery steps out-of-order.
By doing step 3 before step 2 you will likely get into an "Accelerated Spin". (A very rapid increase in rotation.. . .Very dangerous!  But in my experience the LIV-P will fly out of this if it has enough altitude (9500' or more).
But, in the accelerated spin (your mind is probably quite boggled by now!) you finally use step 2 (opposite rudder) and you now are in a Cross-over Spin which, in a flash, will put you into an Inverted Spin! Blanking the rudder! Not good.