X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 31 Jan 2010 23:58:12 -0500 Message-ID: X-Original-Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120] verified) by logan.com (CommuniGate Pro SMTP 5.3.2) with ESMTP id 4106308 for lml@lancaironline.net; Sun, 31 Jan 2010 22:19:54 -0500 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.120; envelope-from=tednoel@cfl.rr.com X-Original-Return-Path: X-Authority-Analysis: v=1.0 c=1 a=lKLLbTvipJ8A:10 a=Ia-xEzejAAAA:8 a=fwegRRApRltSfkUJ57wA:9 a=ooxkKDUxiThfj_RKqB0A:7 a=_LAl-_Cv3H5wSxT89kEYAbqft7gA:4 a=EzXvWhQp4_cA:10 a=D_lJc-YEJU1IKxV-:21 a=OrjGMRCfTATsDxvc:21 a=CjxXgO3LAAAA:8 a=a6lV07ZhL9QxY7XurRQA:9 a=RncKrjWz-GKoFzpzEOcA:7 a=2zUV6-EURCZus_L5OJKFeXpPhSMA:4 a=rC2wZJ5BpNYA:10 X-Cloudmark-Score: 0 X-Originating-IP: 68.204.83.75 Received: from [68.204.83.75] ([68.204.83.75:63223] helo=OfficeDesktop) by cdptpa-oedge02.mail.rr.com (envelope-from ) (ecelerity 2.2.2.39 r()) with ESMTP id 21/ED-05033-738466B4; Mon, 01 Feb 2010 03:19:19 +0000 X-Original-Message-ID: From: "Ted Noel" X-Original-To: "Lancair Mailing List" References: In-Reply-To: Subject: Re: [LML] Re: Engine out gear down Issue/The procedure! This was a wake up call for me.. X-Original-Date: Sun, 31 Jan 2010 22:19:14 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0174_01CAA2C3.6BA99A00" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6002.18005 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6002.18005 This is a multi-part message in MIME format. ------=_NextPart_000_0174_01CAA2C3.6BA99A00 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable It may not be exact, but I've done some live simulations. In a demo = flight of a IV-P we saw 1,600 fpm down at 100 kts clean with a = windmilling prop. I rented a Hershey-bar wing Arrow and did the = following: 3,000' AGL, crosswind over the center of the active runway Chop to idle, dump full flaps, drop gear, prop flat pitch, 30 degree = roll left. Maintain 100 kts -> 1,600 fpm down. 270 degree turn, flare over the numbers, nice landing. It's unusual to say the least, but it worked well in the Arrow. I'm sure = one could argue that 100 kts with a 30 degree bank might lead to an = accelerated stall in the IV-P, but I'm not trying to maintain altitude. = I'm allowing the plane to fall in a controlled manner to the threshold. It was actually quite fun. But be careful if there's traffic in the = pattern. It's really easy to overtake them. I waved off twice due to = traffic before I was able to complete the maneuver. Ted Noel N540TF ----- Original Message -----=20 From: Gary Casey=20 To: lml@lancaironline.net=20 Sent: Sunday, January 31, 2010 9:57 AM Subject: [LML] Re: Engine out gear down Issue/The procedure! This was = a wake up call for me.. I ran through some numbers regarding Michael's comments below. = Starting with the sailplane comment, he says that slowing from 135kts to = 65 in a zoom can result in a gain of 800 feet. If all the energy were = converted to altitude(no drag) the gain would be 1,276 ft, so a gain of = 800 ft seems reasonable for a very low-drag airframe - 2/3 of the energy = can be converted to altitude. In the case mentioned of 120 kts to 75 = kts the number comes out to a gain of 765 ft. How much of that is eaten = up by drag? Certainly compared to the sailplane, a lot. Would the = altitude gain be half? I doubt it. 1/4? Maybe, so as a guess you = could count on perhaps a 200 ft altitude gain. How much do you need to = flare? Depends on the descent rate. I calculated it based on 2,000 = ft/min - arresting that is equivalent to an altitude gain of 34.5 ft, = much lower than the 200 ft mentioned above. It would be good if someone = measured the actual no-power descent rate with gear and flaps down. In summary, the math suggests that a no-power approach speed of 120 = kts should leave more than enough energy to flare. How much more? I'll = bet not a lot, but still more. I don't have an answer to the question, = but this is how the numbers work out. I have done a full-flap no-power = descent with my ES (gear down, of course :-) at 105 kts and the descent = rate was over 2,000 ft/min with a frighteningly high negative deck = angle. Flaring from that condition would be interesting, to say the = least. My conclusion is that Randy's warning is well founded. I would, perhaps, disagree with the admonition that retracting flaps = when on final will result in a guaranteed disaster. Certainly any = change in configuration at the last second creates a high work load, but = at least in my airplane, the difference in behavior between 20 degrees = and 40 degrees of flaps is 90% drag. So, if one were to think he was = high for the landing, added full flaps and then discovered he was now = low, I see no problem with then retracting the flaps to 10 or 20 = degrees. Assuming the speed were high (120?) the flaps could even be = retracted all the way without problem except for the pitch change = required. And then dropping the flaps during the flare is a good way to = arrest the descent. I'm a little reluctant to post this last paragraph = as I have no credentials (no military fighter jet experience, no = instructor rating, no multi-engine jet time, and no stays in Holiday Inn = Express) except for a modest understanding of the engineering principles = involved. Gary ------=_NextPart_000_0174_01CAA2C3.6BA99A00 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
It may not be exact, but I've done some live = simulations.=20 In a demo flight of a IV-P we saw 1,600 fpm down at 100 kts clean with a = windmilling prop. I rented a Hershey-bar wing Arrow and did the=20 following:
 
3,000' AGL, crosswind over the center of the = active=20 runway
Chop to idle, dump full flaps, drop gear, prop = flat pitch,=20 30 degree roll left.
Maintain 100 kts -> 1,600 fpm = down.
270 degree turn, flare over the numbers, nice=20 landing.
 
It's unusual to say the least, but it worked = well in the=20 Arrow. I'm sure one could argue that 100 kts with a 30 degree bank might = lead to=20 an accelerated stall in the IV-P, but I'm not trying to maintain = altitude. I'm=20 allowing the plane to fall in a controlled manner to the = threshold.
 
It was actually quite fun. But be careful if = there's=20 traffic in the pattern. It's really easy to overtake them. I waved off = twice due=20 to traffic before I was able to complete the maneuver.
 
Ted Noel
N540TF
----- Original Message -----
From:=20 Gary=20 Casey
Sent: Sunday, January 31, 2010 = 9:57=20 AM
Subject: [LML] Re: Engine out = gear down=20 Issue/The procedure! This was a wake up call for me..

I ran through some numbers regarding Michael's comments below.=20  Starting with the sailplane comment, he says that slowing from = 135kts to=20 65 in a zoom can result in a gain of 800 feet.  If all the energy = were=20 converted to altitude(no drag) the gain would be 1,276 ft, so a gain = of 800 ft=20 seems reasonable for a very low-drag airframe - 2/3 of the energy can = be=20 converted to altitude.  In the case mentioned of 120 kts to 75 = kts the=20 number comes out to a gain of 765 ft.  How much of that is eaten = up by=20 drag?  Certainly compared to the sailplane, a lot.  Would = the=20 altitude gain be half?  I doubt it.  1/4?  Maybe, so as = a guess=20 you could count on perhaps a 200 ft altitude gain.  How much do = you need=20 to flare?  Depends on the descent rate.  I calculated it = based on=20 2,000 ft/min - arresting that is equivalent to an altitude gain of = 34.5 ft,=20 much lower than the 200 ft mentioned above.  It would be good if = someone=20 measured the actual no-power descent rate with gear and flaps = down.

In summary, the math suggests that a no-power approach speed of = 120 kts=20 should leave more than enough energy to flare.  How much more? =  I'll=20 bet not a lot, but still more.  I don't have an answer to the = question,=20 but this is how the numbers work out.  I have done a full-flap = no-power=20 descent with my ES (gear down, of course :-) at 105 kts and the = descent rate=20 was over 2,000 ft/min with a frighteningly high negative deck angle.=20  Flaring from that condition would be interesting, to say the = least.=20  My conclusion is that Randy's warning is well founded.

I would, perhaps, disagree with the admonition that retracting = flaps when=20 on final will result in a guaranteed disaster.  Certainly any = change in=20 configuration at the last second creates a high work load, but at = least in my=20 airplane, the difference in behavior between 20 degrees and 40 degrees = of=20 flaps is 90% drag.  So, if one were to think he was high for the = landing,=20 added full flaps and then discovered he was now low, I see no problem = with=20 then retracting the flaps to 10 or 20 degrees.  Assuming the = speed were=20 high (120?) the flaps could even be retracted all the way without = problem=20 except for the pitch change required.  And then dropping the = flaps during=20 the flare is a good way to arrest the descent.  I'm a little = reluctant to=20 post this last paragraph as I have no credentials (no military fighter = jet=20 experience, no instructor rating, no multi-engine jet time, and no = stays in=20 Holiday Inn Express) except for a modest understanding of the = engineering=20 principles involved.

Gary
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