Registered Eric Greenwell Posted January 21, 2014 Author Registered Report Share Posted January 21, 2014 I've started a thread about 912 engine pre-heaters at the link below:http://www.touringmotorgliders.org/forum/showthread.php/1834-Engine-pre-heaters?p=2493#post2493Please join it if you have suggestions or comments about using them. Quote Link to comment Share on other sites More sharing options...
Registered Eric Greenwell Posted January 21, 2014 Registered Report Share Posted January 21, 2014 I've started a thread about 912 engine pre-heaters at the link below:http://www.touringmotorgliders.org/forum/showthread.php/1834-Engine-pre-heaters?p=2493#post2493Please join it if you have suggestions or comments about using them. Quote Link to comment Share on other sites More sharing options...
Thermalseeker Posted January 24, 2014 Report Share Posted January 24, 2014 If it's 40F or lower I always preheat the 912s in my Ximango. The way the cowl flap and radiator are done on the Ximango there's room for one of those clamp lights with a 100 w bulb in behind the radiator. I set it up on a timer to come on 4-6 hours before I want to light the fire. Throw a sleeping bag over the cowling and after 4-6 hours it's toasty warm. I can't say for sure, but because the bulb is behind and near the radiator I think I'm getting some thermo-syphon action going on with the coolant. I've noticed the coolant temp is slightly elevated after preheating, too. I also have a 125w oil pan pad heater on the oil tank. After 4-6 hours the oil is about 130F at start up. Sure makes a big difference cranking a 912s when it's warm on a cold day versus when it's cold on a cold day. Quote Link to comment Share on other sites More sharing options...
Thermalseeker Posted January 24, 2014 Report Share Posted January 24, 2014 If it's 40F or lower I always preheat the 912s in my Ximango. The way the cowl flap and radiator are done on the Ximango there's room for one of those clamp lights with a 100 w bulb in behind the radiator. I set it up on a timer to come on 4-6 hours before I want to light the fire. Throw a sleeping bag over the cowling and after 4-6 hours it's toasty warm. I can't say for sure, but because the bulb is behind and near the radiator I think I'm getting some thermo-syphon action going on with the coolant. I've noticed the coolant temp is slightly elevated after preheating, too. I also have a 125w oil pan pad heater on the oil tank. After 4-6 hours the oil is about 130F at start up. Sure makes a big difference cranking a 912s when it's warm on a cold day versus when it's cold on a cold day. Quote Link to comment Share on other sites More sharing options...
Registered Eric Greenwell Posted January 24, 2014 Author Registered Report Share Posted January 24, 2014 The price is right for a 100W bulb, but why did you decide to put a heat pad on the oil but not on the crankcase? They finally began erection of the hangars I'm hoping to be in. The pad and taxiways went in October, and nada since then! It's now a race between the glider being ready and the hangar being ready. The glider finally arrived at the dealers in Florida. Check my blog at http://phoenixarrives.blogspot.com/2014_01_01_archive.html Quote Link to comment Share on other sites More sharing options...
Registered Eric Greenwell Posted January 24, 2014 Author Registered Report Share Posted January 24, 2014 The price is right for a 100W bulb, but why did you decide to put a heat pad on the oil but not on the crankcase? They finally began erection of the hangars I'm hoping to be in. The pad and taxiways went in October, and nada since then! It's now a race between the glider being ready and the hangar being ready. The glider finally arrived at the dealers in Florida. Check my blog at http://phoenixarrives.blogspot.com/2014_01_01_archive.html Quote Link to comment Share on other sites More sharing options...
Thermalseeker Posted January 24, 2014 Report Share Posted January 24, 2014 (edited) Well, the bulk of the oil isn't in the crankcase on a Rotax 9xx, it's in the oil tank. The 912/914 are "dry sump" engines. Warming the oil makes it flow better, so you get better lubrication at start up when it's cold out. Cold start up is when most of your lubrication related wear takes place. The 100 w bulb warms everything under the cowl very well down to about 20F. Much colder than that and my interest in flying rolls off proportional to the temperature in a parabolic curve. In fact, I blew off what looked like a great wave day a couple of days ago here in the Sequatchie because it was 28F on the ground. The lennie associated with the wave looked to be at about 10-12,000', pretty typical of the south wave here. With the screamin' lapse rate that day of about 9F/1000', the air temp would have been around -30F at 12,000'. Too chilly for my blood. As I mentioned I'm pretty sure I'm getting thermo-syphon setting up by heating the coolant in the radiator with the bulb located directly behind it. That in turn, heats the heads and eventually the crankcase. You can put your hand on it after it's been on for a while and feel it. There are jug heaters available for the Rotax 9xx series. Spruce has 'em, but they ain't cheap. http://www.aircraftspruce.com/catalog/eppages/FBpreheatReiff.php?clickkey=46888 There isn't a lot of room to put even a small pad heater on the crankcase of a 912s, though, at least not where it would do any good. The 125w pad is about 4"x6" and can't be cut down. It made more sense to just tape it to the oil tank. Can't say for sure, but there may be some thermo-syphoning going on with the oil, too. The pad also adds considerably to the heat under the cowl, particularly once the tank and oil get warm, helping to warm the rest of the engine. Edited January 24, 2014 by Thermalseeker Quote Link to comment Share on other sites More sharing options...
Gfeldman Posted March 10, 2016 Report Share Posted March 10, 2016 On 1/21/2014 at 3:04 PM, Eric Greenwell said: I've started a thread about 912 engine pre-heaters at the link below: http://www.touringmotorgliders.org/forum/showthread.php/1834-Engine-pre-heaters?p=2493#post2493 Please join it if you have suggestions or comments about using them. Eric I've installed the Reiff pre-heater on my Rotax 912 in my Phoenix. Plugged it in when it was in the low 30'sF. An hour later the cht was 50F. Engine started immediately and presumably with less wear than without preheating. George Feldman (N33GF) Quote Link to comment Share on other sites More sharing options...
Registered Eric Greenwell Posted March 11, 2016 Author Registered Report Share Posted March 11, 2016 I've copied the pre-heater Ed Walker made for his Phoenix. It's a small round unit from Sears that made it easy to connect a flexible duct to it. On Low heat, it's about 600W. The cold days moderated before I could test it, but it raises the under cowl temperatures quickly. The oil temperature indication goes up about 15 deg/hour, but I don't know where that's being measured. Quote Link to comment Share on other sites More sharing options...
pik20e4me Posted March 15, 2016 Report Share Posted March 15, 2016 Looks nice. One of the things I did for my Ximango to help with cold weather starts was have the avionics shop install an external plug for auxiliary power. The 912 is not easy to start the first time in a day, but if you get it started once it tends to work better. So I bought an aux power unit that puts in quite a few amps (don't have the number handy). My back-up plan was to chain together some older 12 volt batteries into a wagon and keep it charged so I could have my own aux power unit with really high amp potential. Quote Link to comment Share on other sites More sharing options...
Jimmyd Posted March 17, 2016 Report Share Posted March 17, 2016 On January 23, 2014 at 11:49 AM, Thermalseeker said: Well, the bulk of the oil isn't in the crankcase on a Rotax 9xx, it's in the oil tank. The 912/914 are "dry sump" engines. Warming the oil makes it flow better, so you get better lubrication at start up when it's cold out. Cold start up is when most of your lubrication related wear takes place. The 100 w bulb warms everything under the cowl very well down to about 20F. Much colder than that and my interest in flying rolls off proportional to the temperature in a parabolic curve. In fact, I blew off what looked like a great wave day a couple of days ago here in the Sequatchie because it was 28F on the ground. The lennie associated with the wave looked to be at about 10-12,000', pretty typical of the south wave here. With the screamin' lapse rate that day of about 9F/1000', the air temp would have been around -30F at 12,000'. Too chilly for my blood. As I mentioned I'm pretty sure I'm getting thermo-syphon setting up by heating the coolant in the radiator with the bulb located directly behind it. That in turn, heats the heads and eventually the crankcase. You can put your hand on it after it's been on for a while and feel it. There are jug heaters available for the Rotax 9xx series. Spruce has 'em, but they ain't cheap. http://www.aircraftspruce.com/catalog/eppages/FBpreheatReiff.php?clickkey=46888 There isn't a lot of room to put even a small pad heater on the crankcase of a 912s, though, at least not where it would do any good. The 125w pad is about 4"x6" and can't be cut down. It made more sense to just tape it to the oil tank. Can't say for sure, but there may be some thermo-syphoning going on with the oil, too. The pad also adds considerably to the heat under the cowl, particularly once the tank and oil get warm, helping to warm the rest of the engine. I have a torpedo heater. I hang a quilt under the engine and place the heater about four ft in front. I place a quilt over the engine. The heat deflects up under the quilt and the engine will be a 70 degrees in 20 min. I have to use duct tape and tape off about 50% of the oil cooler or I cannot keep the oil warm enough. I fly a Lambada with a 912 UL jimmy k Quote Link to comment Share on other sites More sharing options...
Thermalseeker Posted March 24, 2016 Report Share Posted March 24, 2016 My Ximango came from the factory with a "winter plate" to cover about half the oil cooler. It's made from .025" aluminum with 1/2" turn downs on 3 sides to hold it in place on the oil cooler. Quote Link to comment Share on other sites More sharing options...
Gfeldman Posted April 8, 2016 Report Share Posted April 8, 2016 have used a Reiff preheater on the rotax in my Phoenix. It works great. When OAT is near freezing engine temp is 50 degrees F after 1 hour. george (N33GF) Quote Link to comment Share on other sites More sharing options...
Thermalseeker Posted May 31, 2016 Report Share Posted May 31, 2016 On 3/10/2016 at 10:39 PM, Eric Greenwell said: "The oil temperature indication goes up about 15 deg/hour, but I don't know where that's being measured." On most Rotax 9xx series installs I've seen the oil temp probe is installed on the oil pump. Ditto the oil pressure probe, although some locate the actual oil pressure probe itself elsewhere, like on the firewall via a length Aeroquip or similar pressure rated hose. My Ximango has a Volkslogger data logger tied into an Ilec SN10 Flight Computer. The oil pressure probe is remotely located on the firewall, but the hose ties in at the oil pump on the front of the engine. The Volkslogger also has an oil pressure switch which tells the Volkslogger if the engine is running or not. This switch is plumbed in right next to the oil pressure probe. Quote Link to comment Share on other sites More sharing options...
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