Remember!!!in Humid climates You can get carb-ice on an 80F day!!!Meinolf ----- Original Message ----- From: "Mark Langford" <n5...@hiwaay.net> To: "KRnet" <kr...@mylist.net> Cc: "Corvair engines for homebuilt aircraft" <corvaircr...@mylist.net> Sent: Sunday, October 26, 2008 9:35 AM Subject: Re: KR> Heat Source for Carb Heat
Meinolf Ruther wrote: > It was a mod for Piper Apachies, to maintain > good power with allmost full carb-heat. In the wintertime, I use carb heat to some extent full time. Even in the summer, if I'm at anything over about 5000', I'll use some or full carb heat to make the mixture distribution better, which makes the engine run smoother and allows me to lean the mixture more agressively. I'm a firm believer in carb heat. Somebody at SERFI asked me yesterday if I really needed carb heat...and the answer is absolutely, even though I've never experienced carb ice, and I do a lot of flying in carb icing conditions. That may be partly due to the Ellison (even though it says right on it CARB HEAT REQUIRED), or the way I fly it, but I've never seen it on my airplane while flying. I highly recommend carb heat if for no other reason than it makes my engine run smoother and more efficiently due to improved mixture distribution. One way to build a carb heat box is shown at http://home.hiwaay.net/~langford/corvair/airbox/ . While I'm on the subject, I've had an extra temp sensor under my cowling that has proven that during cruise, the temperature under there is only about 20 degrees higher than outside air. I recently moved it to a location under one of the diaphragm screws on my Ellison carb, which is something like 9" away from the exhaust pipe. That sensor sees temperatures that are about 40 degrees warmer than the previous location, which is 60 degrees warmer than ambient. The point being that the Ellison's diaphram cover (the aluminum disk on the side) needs to be shielded from exhaust radiation and/or provided with a blast tube to mimize the possibility of vapor lock. I've experienced vapor lock several times on the ground after letting the engine "heat soak" after refueling on a hot day and taking too long to get back in the air again. Recirculating the fuel back to the tank can prevent vapor lock in the fuel lines, but fuel doesn't circulate through that diaphragm without the engine running, so a heat shield between the exhaust and the diaphragm cover or blast tube will substantially reduce the chance for vapor lock, especially while the engine is turned off and heat soaking. I flew to SERFI (SouthEast Regional FlyIn) and back yesterday, and passed the 700 hour mark on the way back. And I now have 28 hours on WW's front bearing and it's doing great. Oil pressure is exactly the same as it was the first time I flew it, so it's looking and feeling pretty good... Mark Langford, Huntsville, AL website: www.n5...@hiwaay.net email: N56ML at hiwaay.net _______________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html -- No virus found in this incoming message. Checked by AVG. Version: 7.5.549 / Virus Database: 270.8.4/1749 - Release Date: 10/27/2008 7:57 AM
