X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 14 Jun 2007 21:50:51 -0400 Message-ID: X-Original-Return-Path: Received: from smtp1.av-mx.com ([137.118.16.57] verified) by logan.com (CommuniGate Pro SMTP 5.1.9) with ESMTP id 2103440 for lml@lancaironline.net; Thu, 14 Jun 2007 21:43:32 -0400 Received-SPF: pass receiver=logan.com; client-ip=137.118.16.57; envelope-from=pinetownd@volcano.net Received: from DennisDell (63-170-118-5.du.volcano.net [63.170.118.5]) (Authenticated sender: pinetownd@volcano.net) by smtp1.av-mx.com (Postfix) with ESMTP id 5FC3D290218 for ; Thu, 14 Jun 2007 21:42:55 -0400 (EDT) X-Original-Message-ID: <010301c7aeee$7c8af740$6601a8c0@DennisDell> From: "Dennis Johnson" X-Original-To: "Lancair Mailing List" Subject: Boost Pump X-Original-Date: Thu, 14 Jun 2007 18:42:50 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0100_01C7AEB3.CF50B360" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0100_01C7AEB3.CF50B360 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable "My question is: could the output of the two pumps combine and overwhelm = the return line causing pressure and thus fuel flow to go out of = limits?" Just to restate the report of the Bonanza crash, with a TSIO-520 engine. = A Beech test pilot found that taking off with the boost pump on high = resulted in a smooth running engine, but a perceptible loss of power. = He flew above the airport at full power at a safe altitude and with the = boost pump on high. He slowly reduced manifold pressure. The engine = became rough at 35" and suffered a complete loss of power at 31". = Moving the throttle back in did not restart the engine and he recovered = by turning off the boost pump. The NTSB report said that the engine = would quit at 24" manifold pressure with the boost pump on high. The pilots who have recently reported their findings on the LML support = the first half of the above claim, that high boost at full power does = not kill the engine. But those findings don't contradict the second = part of the claim, that high boost will kill the engine below either 31" = MAP (Beech test pilot) or 24" (NTSB). I'm not planning to test it in my = airplane; I'll stay on the ground and have a beer instead. =20 Source: Flying magazine's Aftermath article September 2004. Best, Dennis Johnson Legacy ------=_NextPart_000_0100_01C7AEB3.CF50B360 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable

"My question is: could the = output of=20 the two pumps combine and overwhelm the return line causing pressure and = thus=20 fuel flow to go out of limits?"

Just to restate the report of the Bonanza crash, = with a=20 TSIO-520 engine. A Beech test pilot found that taking off with the = boost=20 pump on high resulted in a smooth running engine, but a perceptible loss = of=20 power. He flew above the airport at full power = at a=20 safe altitude and with the boost pump on high. He slowly reduced = manifold=20 pressure. The engine became rough at 35" and suffered a complete = loss of=20 power at 31". Moving the throttle back in did not restart the = engine and=20 he recovered by turning off the boost pump. The NTSB report said = that the=20 engine would quit at 24" manifold pressure with the boost pump on=20 high.

The pilots who have recently reported their findings = on the=20 LML support the first half of the above claim, that high boost at full = power=20 does not kill the engine. But those findings don't contradict the = second=20 part of the claim, that high boost will kill the engine below either 31" = MAP=20 (Beech test pilot) or 24" (NTSB). I'm not planning to test it in = my=20 airplane; I'll stay on the ground and have a beer=20 instead.

Source: Flying magazine's = Aftermath=20 article September 2004.

Best,

Dennis Johnson

Legacy

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