X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 08 Sep 2008 15:30:34 -0400 Message-ID: X-Original-Return-Path: Received: from smtp-ext-04.mx.pitdc1.expedient.net ([206.210.69.144] verified) by logan.com (CommuniGate Pro SMTP 5.2.7) with ESMTPS id 3118872 for lml@lancaironline.net; Sun, 07 Sep 2008 21:33:14 -0400 Received-SPF: none receiver=logan.com; client-ip=206.210.69.144; envelope-from=rpastusek@htii.com Received: from dlhtpax009 (c-98-218-217-188.hsd1.va.comcast.net [98.218.217.188]) by smtp-ext-04.mx.pitdc1.expedient.net (Postfix) with ESMTPSA id 8A6ECE49FC for ; Sun, 7 Sep 2008 21:32:40 -0400 (EDT) Reply-To: From: "Robert Pastusek" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: RE: [LML] IV-P Flaps - Theory of Operation X-Original-Date: Sun, 7 Sep 2008 21:32:39 -0400 Organization: Holmes-Tucker International, Inc. X-Original-Message-ID: <008901c91152$c8a1b0c0$59e51240$@com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_008A_01C91131.419010C0" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AckRNl/N0G3NYx9ZRX2it23T2pxO4gAGbwug Content-Language: en-us This is a multipart message in MIME format. ------=_NextPart_000_008A_01C91131.419010C0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Richard, Write or call me off-line and I'll go through the details with you, but the basic theory of operation is that the flap cylinder has pressure applied to both the extend and retract sides when the flap control lever is in the up position. The flaps are held up/retracted in this situation because the piston surface area inside the flap operating cylinder is less (by the cross section of the operating rod) on the extend side than on the retract side. This causes the flaps to retract when normal pressure is applied to the hydraulic system. The flaps are extended by venting/dumping the pressure to the larger side of the cylinder, causing it to move the other direction. Lancair provides an adjustable valve to control the rate of extension, and it is useful. I installed an additional valve in the "retract" side of the cylinder (stock item from McMaster Carr) that free-flows in one flow direction and is adjustable in the other. This allows me to set both the extend and retract speed to approximately 4 seconds each way. In the "stock" configuration, my flaps would retract in about one second-fast enough to cause difficulty in controlling the pitching moments during takeoff/go around. Hope this helps. Bob Pastusek N437RP @ 90 hours Folks, I know little about hydraulics . That said I do not understand how the flaps work on the IV-P. One side of the flap cylinder goes to a metering valve and then to the high pressure manifold. The other side of the flap cylinder goes to the three position flap control . I assume that in one direction it is manifold pressure, the other direction it is reservoir pressure, and in neutral it is sealed. So I can understand what happens when you have the following: 1) Flap Switch on reservoir pressure and consequently one side of the flap cylinder, and the other metered from the manifold. 2) I also understand when the flap is neutral, than no-oil flowing means the flap is locked in the current position. But how do things work when: 3) The Flap Switch is on manifold pressure and consequently one side of flap cylinder, and the other metered from the manifold ? Inquiring minds want to know, thanks! Richard T. Schaefer E-mail: schaefer@RTS-Services.com RTS Services Inc Web: http://www.RTS-Services.com 7330 Cave Hollow ___ Voice: (512) 923-2755 Austin, TX 78750 | Fax: (830) 798-9644 `---------(*)---------' ------=_NextPart_000_008A_01C91131.419010C0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Richard,

 

Write or call me off-line and I’ll go through the = details with you, but the basic theory of operation is that the flap cylinder = has pressure applied to both the extend and retract sides when the flap = control lever is in the up position. The flaps are held up/retracted in this = situation because the piston surface area inside the flap operating cylinder is = less (by the cross section of the operating rod) on the extend side than on the = retract side. This causes the flaps to retract when normal pressure is applied = to the hydraulic system. The flaps are extended by venting/dumping the pressure = to the larger side of the cylinder, causing it to move the other direction. =

 

Lancair provides an adjustable valve to control the rate = of extension, and it is useful. I installed an additional valve in the = “retract” side of the cylinder (stock item from McMaster Carr) that free-flows in = one flow direction and is adjustable in the other. This allows me to set both the = extend and retract speed to approximately 4 seconds each way. In the = “stock” configuration, my flaps would retract in about one second—fast = enough to cause difficulty in controlling the pitching moments during takeoff/go = around.

 

Hope this helps…


Bob Pastusek

N437RP @ 90 hours

 

Folks,

  I know little about hydraulics … That said I do not understand how = the flaps work on the IV-P.

 

One side of the flap cylinder goes to a metering valve and then to the high pressure manifold.

The other side of the flap cylinder goes to the three position flap control = …

I assume that in one direction it is manifold pressure, the other = direction it is reservoir pressure, and in neutral it is sealed.

 

So I can understand what happens when you have the = following:

  &= nbsp;         1) Flap Switch on reservoir pressure and consequently one side of the = flap cylinder, and the other metered from the manifold.

  &= nbsp;         2) I also understand when the flap is neutral, than no-oil flowing means = the flap is locked in the current position.

 

But how do things work when:

3)  The Flap Switch is on = manifold pressure and consequently one side of flap cylinder, and the other = metered from the manifold ?

 

Inquiring minds want to know,   thanks!

 

 

Richard T. Schaefer      E-mail: schaefer@RTS-Services.com

RTS Services Inc          Web: = http://www.RTS-Services.com

7330 Cave Hollow         ___        Voice:  (512) = 923-2755
Austin, TX 78750          = |         Fax:    (830) 798-9644
            &= nbsp;  `---------(*)---------'

 

 

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