Return-Path: Sender: (Marvin Kaye) To: lml Date: Tue, 08 Oct 2002 18:12:44 -0400 Message-ID: X-Original-Return-Path: Received: from imo-m07.mx.aol.com ([64.12.136.162] verified) by logan.com (CommuniGate Pro SMTP 4.0b9) with ESMTP id 1800573 for lml@lancaironline.net; Tue, 08 Oct 2002 17:20:44 -0400 Received: from Sky2high@aol.com by imo-m07.mx.aol.com (mail_out_v34.13.) id q.11b.17e99e2a (3842) for ; Tue, 8 Oct 2002 17:20:37 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <11b.17e99e2a.2ad4a625@aol.com> X-Original-Date: Tue, 8 Oct 2002 17:20:37 EDT Subject: Fuel Cooling X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_11b.17e99e2a.2ad4a625_boundary" X-Mailer: AOL 8.0 for Windows US sub 120 --part1_11b.17e99e2a.2ad4a625_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit The question about vapor lock did not mention airplane model or engine type. In Lancair 320/360s, the cowl area behind the baffling can get hot since there is no air movement there. One way to help this is with 1 or 2 one inch blast tubes to help keep some components cool when the airplane is moving. A hot stopped or idling engine can heat soak the engine mounted pump which can cause fuel to vaporize in the pump thus leading to cavitation. I don't know the consequence with a carbureted engine, but an injected engine can lose important fuel pressure because of the cavitation - the instant remedy is to run the boost pump to keep the pressure up and, perhaps, re-liquify the vapor. Injected engine hot starts are very difficult when the above situation occurs. Of course, if you have an engine with a fuel return line, such as a Continental, you can run the boost pump with the mixture at idle cut-off for a minute or so to use cool fuel to cool the engine pump and return the heated fuel to the tank. Scott Krueger N92EX --part1_11b.17e99e2a.2ad4a625_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: 7bit The question about vapor lock did not mention airplane model or engine type.

In Lancair 320/360s, the cowl area behind the baffling can get hot since there is no air movement there.  One way to help this is with 1 or 2 one inch blast tubes to help keep some components cool when the airplane is moving.  A hot stopped or idling engine can heat soak the engine mounted pump which can cause fuel to vaporize in the pump thus leading to cavitation.  I don't know the consequence with a carbureted engine, but an injected engine can lose important fuel pressure because of the cavitation - the instant remedy is to run the boost pump to keep the pressure up and, perhaps, re-liquify the vapor. 

Injected engine hot starts are very difficult when the above situation occurs.  Of course, if you have an engine with a fuel return line, such as a Continental, you can run the boost pump with the mixture at idle cut-off for a minute or so to use cool fuel to cool the engine pump and return the heated fuel to the tank.

Scott Krueger
N92EX --part1_11b.17e99e2a.2ad4a625_boundary--