Return-Path: Received: from fep03-svc.tin.it ([212.216.176.34]) by ns1.olsusa.com (Post.Office MTA v3.5.3 release 223 ID# 0-64832U3500L350S0V35) with ESMTP id com for ; Tue, 2 May 2000 11:44:59 -0400 Received: from tin.it ([212.216.215.220]) by fep03-svc.tin.it (InterMail vM.4.01.02.27 201-229-119-110) with ESMTP id <20000502155047.GBYA19811.fep03-svc.tin.it@tin.it> for ; Tue, 2 May 2000 17:50:47 +0200 Message-ID: <390EFAAF.2E716D86@tin.it> Date: Tue, 02 May 2000 17:56:31 +0200 From: "John F. Herminghaus" Reply-To: catignano@tin.it Organization: Engineer To: "lancair.list@olsusa.com" Subject: 24V vs. 12V X-Mailing-List: lancair.list@olsusa.com Mime-Version: 1.0 <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Aside from the slight savings in weight, the only significant difference between 12 and 24 v. is in the alternators. The only ones I have been able to find, produce 60amps regardless of the voltage. So for 12v. you have 600 watts available to power everything on the plane, with 24v. 1200. On the IV the hydraulic pump draws 500 watts. That leaves 100 watts, which is less than an average com draws when transmitting. To say nothing of all the other whistles and bells that you have probably installed. Imagine being on an IMC approach at night, (landing lights, nav lights in addition to everything else) and having the alternator fuses blow when you put down your gear. OK, maybe you shouldn't take that risk, but situations like that do occur, often without forewarning. IMHO the alternator should be to handle normal operations, excepting starting, without drawing on the battery. What would you do if you had a battery failure? It is true that almost all equipment is available in 12v, but the same is true for 24v. when you're looking at new equipment. With the amount of electronics being put on planes, the trend will inevitably be towards 24v. After reading the Lancair information on the matter, my order was for 12v. When I found out how much the hydraulic pump drew, I changed to 24v., which Lancair did at no penalty. Thanks, Lance. John Herminghaus LIV-P I-VVVV P.S. According to an Oildyne graph, the 12v. pump draws slightly more than 50 amps at 1000psi. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LML website: http://www.olsusa.com/Users/Mkaye/maillist.html Builders' Bookstore: http://www.buildersbooks.com/lancair Please send your photos and drawings to marvkaye@olsusa.com. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>