X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 27 Oct 2011 16:14:50 -0400 Message-ID: X-Original-Return-Path: Received: from mta11.charter.net ([216.33.127.80] verified) by logan.com (CommuniGate Pro SMTP 5.4.2) with ESMTP id 5174945 for lml@lancaironline.net; Thu, 27 Oct 2011 14:10:37 -0400 Received-SPF: pass receiver=logan.com; client-ip=216.33.127.80; envelope-from=troneill@charter.net Received: from imp10 ([10.20.200.15]) by mta11.charter.net (InterMail vM.8.01.05.02 201-2260-151-103-20110920) with ESMTP id <20111027181002.VOJF4019.mta11.charter.net@imp10> for ; Thu, 27 Oct 2011 14:10:02 -0400 Received: from [192.168.1.100] ([75.132.241.174]) by imp10 with smtp.charter.net id puA11h00C3mUFT705uA1bW; Thu, 27 Oct 2011 14:10:02 -0400 X-Authority-Analysis: v=1.1 cv=CKBBFOpPYfBSFfEY1Rl9efxuAv/fdt7oFsWUUq3BrLQ= c=1 sm=1 a=VBY9H4zE2BIA:10 a=yUnIBFQkZM0A:10 a=VxlS/kh5Y2KhHY/Xui1ATg==:17 a=xMGpOozMAAAA:8 a=3oc9M9_CAAAA:8 a=ruFn_6x7gscaH-rReh4A:9 a=2UdkUjzjERJHcCDycyUA:7 a=CjuIK1q_8ugA:10 a=U8Ie8EnqySEA:10 a=9NARQkKF_OHomRp7B_UA:9 a=oMw9_9RPn4kBmdBBOvwA:7 a=RhAnTGPKbOYA:10 a=gTt9TlXs2RwA:10 a=VxlS/kh5Y2KhHY/Xui1ATg==:117 From: Terrence O'Neill Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: multipart/alternative; boundary=Apple-Mail-143--18098669 Subject: Re: [LML] Re: Fw: Updated SUMMARY OF LANCAIR ACCIDENTS IN NTSB DATABASE X-Original-Date: Thu, 27 Oct 2011 13:10:01 -0500 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <39EB6116-2989-4A87-9E3F-4D3F955D849E@charter.net> X-Mailer: Apple Mail (2.1084) --Apple-Mail-143--18098669 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Scott, Au contraire mon ami. =20 You saw my wing with its free-vane-type AOA, mounted at BL+47. =20 In flight it is my trim tab that maintains the wing's AOA for each = airspeed and tail loading (CG vs lift center), and only my light = fingertip pressure make corrections for altitude/power).=20 This works in my bird in calm or gusty air. I haven't flown with one of the 'magic lights' or digital AOAs, but the = results should be about the same as with my free-vane-type AOA. =20 Watch your AOA, -hands off-, in gusty or smooth air, zooming up or = diving, and note that the AOA stays as trimmed.=20 But with - hands on - the stick, I am overriding the trim, and control = of the wing's AOA, and it moves instantly with my stick movement, as if = it were string-attached vane-to-stick. =20 If your AOA doesn't react like that, it's got lag in the system. What = kind of AOA do you have? Operating near the stall, at high AOAs (regardless of airspeed) the = wing's AOA is commanded by the stabilizer/elevator/trim unless = overridden by the pilot ... who is responsible for his input. If he deliberately pulls the wing into a stall AOA, (which he can SEE on = this AOA) he is deliberately giving away his pitch control. Then he has = to use the elevator-stabilizer to reduce the wing's AOA. In the CAFE = test of a 320/360 the pilot noted that the stall recovery was marginal. = In a professional/military test pilot report at = (www.eaa1000.av.org/fltrpts/lanc360/hq.htm) gives the details regarding = high and stall AOA and recovery of the small tail LNC2s, which prompted = me to put slots on my horizontal stabilizer. I wasn't sure how these = tests applied to the 235/320, but I thought -- close enough. The = alternative was to be cautious about stalling the plane, and, to also be = able to SEE how close I was to the stall AOA. You mentioned steep turns to final. It is not the bank angle but the = pulling back on the stick for a balanced turn that increases the AOA. I = watch the AOA vane while pulling the wing into an untrimmed AOA, but = keep the AOA vane angle well below the marked stall AOA, (my tab trims = only down to about 85 w/ gear down and flaps, rear CG) and the AOA = responds just as though I had a string attaching the stick to the free = vane. I keep about 5 degrees in reserve for a little extra lift needed = to flare and slow to touchdown.=20 =20 When first flying with my homemade AOA (1970) while testing my O' Model = W, I was delighted to be able to fly very close to the NACA 4415's stall = AOA and minimum airspeed with confidence, and thought I'd see if i could = land right at the start of the runway and turn off at the run-up area... = so when I got right down to the runway to flare and pulled back... there = was no more CL at that high angle. Some airfoils have a gradual peak a = little past the top of the lift curve, and I'd been flying in that max = lift area. So I made a 'carrier landing' ... that is, I flew right into = the concrete with a big bang.. Fortunately I had made the landing gear = nice and strong. I got out and looked everything over, and no damage, = except to my ego. But I learned to respect the airfoil's gradual max = lift peak, add reduced my AOA down to final.=20 If (hands off) a plane wants to pitch up or down regardless of the pitch = trim setting, then it is dangerously unstable because the CG is aft of = the plane's lift center ... aft of where the CG is not supposed to be... = unless you have artificial stabilization. Regarding slowing in in chop or turbulence, I don't know what would = cause that. Maybe some small zone on the plane is just a gentle enough = curve that it is low drag unless bumped..? Some planes have a 'bucket' = of low drag in a narrow AOA range, and have to be flown fast enough to = get the AOA down into the bucket at cruise power... but if approached = slowly by setting the cruise power too early they don;t get up to speed. = So the pilot leaves climb power on until he's in the bucket, and then = can reduce power and stay there. My comments are based on my own experience flying with my vane, in my = Model W, in my Magnum Pickup, a Mitchell B-10 Wing, in a Dragonfly, a = Challenger, and in the 235/320. =20 I don't want to be stalled either. : ) Terrence On Oct 27, 2011, at 10:08 AM, Sky2high@aol.com wrote: > Terrence, > =20 > Yes, but the statement is too simple and is only true in smooth air = under a constant load. The flying wing AOA (angle between wing and air = flow) is not always under control of the pilot. Operating at an air = speed near the stall AOA allows the wing to stall if the air is not = smooth such as perturbations from turbulence (wake, wind shear, gusts, = etc.)=20 > =20 > Pilot control is a component when operating near the stall AOA and = loading up the wing without increasing the air flow that increases the = AOA leading to a wing stall (i.e. low speed base to final turn where the = bank angle is increased and the stick is pulled to line up with the = runway on final). > =20 --Apple-Mail-143--18098669 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii hands off-, in gusty or = smooth air, zooming up or diving, and note that the AOA stays as = trimmed. 
But with - hands on - the stick,  I am overriding = the trim, and control of the wing's AOA, and it moves instantly with my = stick movement, as if it were string-attached vane-to-stick. =  
If your AOA doesn't react like that, it's got lag in = the system.  What kind of AOA do you = have?

Operating near the stall, at high AOAs = (regardless of airspeed) the wing's AOA is commanded by the = stabilizer/elevator/trim unless overridden by the pilot ... who is = responsible for his input.
If he deliberately pulls the wing = into a stall AOA, (which he can SEE on this AOA) he is deliberately = giving away his pitch control.  Then he has to use the = elevator-stabilizer to reduce the wing's AOA.  In the CAFE test of = a 320/360 the pilot noted that the stall recovery was marginal.  In = a professional/military test pilot report at (www.eaa1000.av.o= rg/fltrpts/lanc360/hq.htm)  gives the details regarding high = and stall AOA and recovery of the small tail LNC2s, which prompted me to = put slots on my horizontal stabilizer.  I wasn't sure how these = tests applied to the 235/320, but I thought -- close enough.  The = alternative was to be cautious about stalling the plane, and, to also be = able to SEE how close I was to the stall = AOA.

You mentioned  steep turns to final. =  It is not the bank angle but the pulling back on the stick for a = balanced turn that increases the AOA.  I watch the AOA vane while = pulling the wing into an untrimmed AOA, but keep the AOA vane angle well = below the marked stall AOA, (my tab trims only down to about 85 w/ gear = down and flaps, rear CG) and the AOA responds just as though I had a = string attaching the stick to the free vane.  I keep about 5 = degrees in reserve for a little extra lift needed to flare and slow to = touchdown. 
 
When first flying with my = homemade AOA (1970) while testing my O' Model W, I was delighted to be = able to fly very close to the NACA 4415's stall AOA and minimum airspeed = with confidence, and thought I'd see if i could land right at the start = of the runway and turn off at the run-up area... so when I got right = down to the runway to flare and pulled back... there was no more CL at = that high angle.  Some airfoils have a gradual peak a little past = the top of the lift curve, and I'd been flying in that max lift area. =  So I made a 'carrier landing' ... that is, I flew right into the = concrete with a big bang..  Fortunately I had made the landing gear = nice and strong.  I got out and looked everything over, and no = damage, except to my ego.  But I learned to respect the airfoil's = gradual max lift peak, add reduced my AOA down to = final. 

If (hands off) a plane wants = to pitch up or down regardless of the pitch trim setting,  then it = is dangerously unstable because the CG is aft of the plane's lift center = ... aft of where the CG is not supposed to be... unless you have = artificial stabilization.

Regarding slowing in = in chop or turbulence, I don't know what would cause that. Maybe some = small zone on the plane is just a gentle enough curve that it is low = drag unless bumped..?  Some planes have a 'bucket' of low drag in a = narrow AOA range, and have to be flown fast enough to get the AOA down = into the bucket at cruise power... but if approached slowly by setting = the cruise power too early they don;t get up to speed.  So the = pilot leaves climb power on until he's in the bucket, and then can = reduce power and stay there.

My comments are = based on my own experience flying with my vane, in my Model W, in my = Magnum Pickup, a Mitchell B-10 Wing, in  a Dragonfly, a Challenger, = and in the 235/320.  
I don't want to be stalled either. =  : = )

Terrence

On Oct = 27, 2011, at 10:08 AM, Sky2high@aol.com wrote:

Terrence,
 
Yes, but the statement is too simple and is only true in = smooth=20 air under a constant load.  The flying wing AOA (angle between wing = and air=20 flow) is not always under control of the pilot.  Operating at = an air=20 speed near the stall AOA allows the wing to stall if the air is not = smooth=20 such as perturbations from turbulence (wake, wind shear, gusts, = etc.) =20
 
Pilot control is a component when operating near the stall AOA and = loading=20 up the wing without increasing the air flow that increases the AOA = leading=20 to a wing stall (i.e. low speed base to final turn where the bank = angle is=20 increased and the stick is pulled to line up with the runway on=20 final).
=
 
<= /div>
= --Apple-Mail-143--18098669--