---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Mon 08/30/21: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:58 AM - Momentary Power Loss (Stressmerchant) 2. 04:44 AM - Re: Momentary Power Loss (Richard Goode) ________________________________ Message 1 _____________________________________ Time: 03:58:31 AM PST US Subject: Yak-List: Momentary Power Loss From: "Stressmerchant" I had a little heart-stopping moment on a routine flight yesterday. I was at about 2,000 ft on cruise settings when the engine very briefly cut, and then resumed as if nothing had happened. No warning, no odd behaviour afterwards, just a second of no power. The same thing happened about 5 minutes later, although I had the impression that the second time the power did not die completely, just cut back and then resumed. CHT, Oil temp, oil pressure, fuel pressure all normal. Some searching through the archives here suggests that it could be the coils starting to go. I did wonder about carb icing, but the inlet temp was above freezing. The aircraft is due for annual maintenance next week, so if something needs changing this would be a good time to do it. Any ideas about other potential causes? Read this topic online here: http://forums.matronics.com/viewtopic.php?p=503006#503006 ________________________________ Message 2 _____________________________________ Time: 04:44:37 AM PST US From: "Richard Goode" Subject: RE: Yak-List: Momentary Power Loss I have to begin by saying that I'm completely biased on this topic, but this symptom is extremely common and quite specifically caused by a breakdown of the capacitor inside the coil through a combination of heat and age. The symptoms you describe are absolutely typical, although no one has ever been able to explain why the whole engine momentarily stops, given that one presumably has one good coil and magneto. But it does! And if you continue to fly, it will slowly get worse until the engine will completely stop for several seconds, always after he to soak through to the magneto so typically after 25/30 minutes of flight. As I wrote, we are biased since we have, after a lot of research, developed a totally new coil with an external capacitor so does not have this problem of the capacitor overheating inside the coil of hotwire and indeed for which we have obtain full certification from EASA (European FAA) for these coils. We have them in stock with John Warwick of the YakCollection in San Diego to avoid excessive courier costs from Europe. I have also prepared a more detailed paper on this topic and can send it to anyone if you ask us by email. Richard RICHARD GOODE AEROBATICS Rhodds Farm, Lyonshall, Hereford, HR5 3LW, UK Tel: +44 (0)1544 340120 Fax: +44 (0)1544 340129 e-mail: richard.goode@russianaeros.com www.russianaeros.com WORLD LEADERS IN RUSSIAN SPORTING AIRCRAFT & ENGINES In partnership with Aerometal Kft, Hungary. -----Original Message----- From: owner-yak-list-server@matronics.com On Behalf Of Stressmerchant Sent: 30 August 2021 11:58 Subject: Yak-List: Momentary Power Loss --> I had a little heart-stopping moment on a routine flight yesterday. I was at about 2,000 ft on cruise settings when the engine very briefly cut, and then resumed as if nothing had happened. No warning, no odd behaviour afterwards, just a second of no power. The same thing happened about 5 minutes later, although I had the impression that the second time the power did not die completely, just cut back and then resumed. CHT, Oil temp, oil pressure, fuel pressure all normal. Some searching through the archives here suggests that it could be the coils starting to go. I did wonder about carb icing, but the inlet temp was above freezing. The aircraft is due for annual maintenance next week, so if something needs changing this would be a good time to do it. Any ideas about other potential causes? Read this topic online here: http://forums.matronics.com/viewtopic.php?p=503006#503006 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message yak-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Yak-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/yak-list Browse Digests http://www.matronics.com/digest/yak-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.