On Monday, March 31, 2014 10:4= 2 AM,=20 "Sky2high@aol.com" <Sky2high@aol.com> wrote:

Doug,

There is always room for refinement.

A fighter pilot is not a Lancair pilot. Did he land your=20 plane? Perhaps your question would be best answered by an experienc= ed=20 Lancair Instructor.

In certificated type airplanes that are built to the = same=20 specs and on jigs, Vso is test flight determined - perhaps= for=20 max gross weight, rearward CG loading, etc. Perhaps not. But,= =20 usually these aircraft go through thorough stall tests at various fl= aps=20 setting, weights and CGs with the stuff out. Then Vso is determined= in=20 reality or is computed and verified from design specs.

Notice that V speeds are IASs. This can work because= the=20 IAS indication is calibrated via flight test and the correction data for= =20 position, instrument and system error is noted in the=20 POH. Of course, one wonders if the correction data was obtained at = all=20 attitudes (AOA) and speeds.

I believe your aircraft is unique as denoted in the manufacturer's f= ield=20 on the registration form. So, has your ASI been calibrated? W= as=20 Vso determined through exhaustive tests at differing parameters?

I don't know if you can get creative with your AOA=20 system settings as I am not familiar with it. I did use t= he=20 forerunner to the Advance Systems system that uses upper and lower w= ing=20 pressures along with pitot-static data to determine AOA. The slope = of=20 the straight line function was established by flight-setting tw= o=20 points on that line.

Vso x 1.3 (if a useful Vso is known) may not provide enough=20 safety margin for high performance Lancairs in differing configurati= ons=20 and weather conditions - like turbulence on final or trying to fly close = in=20 square patterns.

There are techniques to overcome slowness or dangerous flat approach= es=20 such as a steeper approach angle to retain enough kinetic energy for flig= ht=20 path corrections, although this requires care to stop the descent hi= gh=20 enough above the runway.

Good luck,

Scott Krueger.

In a message dated 3/31/2014 6:35:55 A.M. Central Daylight Time,=20 douglasbrunner@earthlink.net writes:

Scott,

I=20 understand that the AOA takes into account atmospheric conditions, g=20 loading, weight of the plane, etc. That is why I am interested in= it=20 rather than just using airspeed. My problem is that one of the po= ints=20 to be used for calibration is, in my opinion, a subjective=20 point.

You=20 say that 1.3 Vso is dangerous with a high performance wing. What= =20 number is a better one?

I=20 was taught to fly final at 110 and to slow to 90 over the numbers =E2= =80=93 which is=20 what I normally do. Recently, I flew with a retired fighter pilot= who=20 told me I was too fast on final. I told him that it was better to= be=20 too fast and land long than be too slow and stall. But it started= me=20 thinking about a more optimal speed given how much runway I frequently= =20 use.

From: Lancair= =20 Mailing List [mailto:lml@lancaironline.net] On Behalf Of=20 Sky2high@aol.com
Sent: Sunday, March 30, 2014 5:24=20 PM
To: lml@lancaironline.net
Subject: [LML] Re: FW:= =20 Adding an AOA

Doug,

Sophisticated=20 AOA indications take into account atmospheric conditions and G-loading = along=20 with IAS. In theory, there are straight line functions between=20 interesting points on the relevant AOA such as best glide, stall, etc.&= nbsp;=20 The old fashioned 1.3 Vso is dangerous in aircraft with high performanc= e=20 wings - because the stall speed does vary with G-load and, uh, the=20 air. In Lancairs, 1.3 Vso does not provide proper margins in= all=20 cases.

The=20 sophisticated AOA systems need only 2 points on the straight line = to=20 calibrate the function (uh. the parallel straight line moves becau= se of=20 the other parameters. Some system calibrations do not require the= =20 stall point as one measure (see Advanced Systems). Some requ= ire=20 the zero G (zero lift) point as one. Be careful.

Simpler=20 system rely merely on AOA to the relative wind. This is useful be= cause=20 exceeding the stall AOA results in a stall. The sophisticate= d=20 systems yield other useful information (best glide, etc).

<= /DIV>

Do=20 further study to educate yourself about AOA.

Scott=20 Krueger

In=20 a message dated 3/30/2014 2:35:00 P.M. Central Daylight Time, douglasbrunner@earthlin= k.net=20 writes:

Terrence,

There=20 is no =E2=80=9Cangle=E2=80=9D to mark. Both instruments use an = array of colored=20 lights - in both, the top colored light is a red arrow pointing= down=20 =E2=80=93 presumably this is to indicate a stall.

The=20 way that both are made to be used is to define a safe speed (roughly = 1.3=20 Vso) that can be used during landing (and other maneuvers)

My=20 question was whether to set it to 1.3 Vso or to do the maneuver descr= ibed=20 in the setup.

D.=20 Brunner

From:=20 Lancair Mailing List [mailto:lml@lancaironline.net= ]=20 On Behalf Of Terrence O'Neill
Sent: Sunday, March 30= ,=20 2014 2:18 PM
To: lml@lancaironline.netSubject:=20 [LML] Re: FW: Adding an AOA

D.,

IMHO= the=20 prime purpose of an AOA is:

T= o make=20 the wing's STALL ANGLE visible to the pilot. You do that = by=20 flying the plane and stalling it as you watch the AOA... then mark th= at=20 angle.

The = next most=20 useful AOA info is the best L/D or best R/C... done the same way... f= ly=20 the plane while watching the best R/C for a given power setting, and = make=20 that angle.

Terrence

L235/320

N211AL

On M= ar 30,=20 2014, at 9:23 AM, Douglas Brunner wrote:

I am thi= nking=20 of adding an AOA to my plane. The two models that I am looking = at=20 are the Bendix King KLR 10 (http://www.bendixking.com/Products/Flight-Controls-In= dicators/Indicators/KLR-10)=20 and one of the Alpha Systems units (http://www.alphasystemsaoa.com/)

My quest= ion has=20 to do with the calibration. Both systems require a calibration = at 3=20 points:

1. = On=20 Ground

2. = Optimum = Alpha=20 Angle

3. = Cruise