Engine Preheat Systems

[Rollie]

I went an entirely different route. I took a small electric space heater and added a bit of ducting so that I can set it under the plane and it routes the heat up into the cowl exit area. 45-60 minutes and the entire engine is nice and warm, the engine cranks like it does on a warm summer day and the oil temp is already 70-80 degrees F and the pressure is where it belongs. I have never lived close enough to my hangar to make it convenient to plug in a heater 4 hours before I want to fly, but 45-60 minutes? That works great to turn it on, preflight and maybe go over to the FBO and get warm for a few minutes or run to get breakfast while it warms up (if the flight isn't to a breakfast fly-in) I will add that if my wife is going with me 45 minutes is entirely too long to wait.

Another reason I went this route is my last plane was certified so it was more convenient to do this that add an STC for a heater. So I already had this setup when I started flying my Bearhawk.

[Tim213]

Here in Southern California we rarely have to use engine preheat so I don’t have any personal experience with it. However I also have a RV7 I built, and this was recently discussed on the Vans forum. An after market company called AntiSplat Aero that manufacturers items mostly for RVs, has a new engine preheater that threads directly into an oil drain on Lycoming engines. It was tested by numerous pilots for a year before being available to purchase.
the comments on the forum were very positive. They sold out the first batch of units in two days. At a price of $89 I was even going to get one but now have to wait for the next run of units to be made. Just something to consider as it seems to be pretty much hassle free.

https://antisplataero.com/products/no-hassle-engine-pre-heater

[m.mooney]

Very happy with the Reiff system that I have on my Patrol. I also considered Tanis but went with Reiff because of the cylinder bands. I would choose it again, for sure. Nothing against Tanis, I’m sure it’s a very good system. I have an engine blanket from Bruce’s and preheat every time I fly in the winter, regardless of temperature. I use a smart plug/app and hangar Wifi. When away from home, a small propane generator does the trick with one green bottle. The blanket is a critical component, in my opinion. Generally, I’m shocked at the percentage of aircraft owners that don’t preheat.

[Bcone1381]

Another Viewpoint:

I'm a Tanis fan. Tanis heats the cylinder head using a threaded element in the valve cover. The Reiff ring around the cylinder base has difficulty getting heat to the head. Here is a shot on Tanis website of an engine with 3 cylinders heated by Reiff's band around the cylinder base, and the bottom three heated by Tanis' element in the valve cover screw. After 36 hours the red shows warm cylinder heads.

Tanis claims there warm cylinders are above the dewpoint so no condensation will form there. So Tanis says it fine to leave it plugged in. A Prop is a big heat sink....metal even bigger... and a constant speed prop will form corrosion in its hub if condesation forms there. I'd be putting my prehearter on a remote switch of some kind that I can control at home.

Tanis FAQ has good data on leaving it on. https://www.tanisaircraft.com/faq/

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[AKKen07]

Hey Rod, the guys I’ve spoken to about this around here seem to prefer the Reiff system. Think it heats the whole engine more evenly but, in addition, using a car heater of some sort inside a cowling cover compounds the positive effects. Most Everybody agrees that you are better off not heating the engine 24/7 but just long enough before a flight to heat the engine evenly. But, my thought is that as long as your engine components are not oscillating temperatures frequently, keeping it warm can’t hurt - you’d have to be sure your solution kept everything warm regardless of weather conditions…. That’s speculation.
Most of this is 2nd hand but it’s from talks with good experienced Alaska GA pilots and mechanics. I only heat up a plane before I go flying but I can’t prove the results.

[rodsmith]

I hadn't come across the twin hornet. Looks like a viable alternative with an insulated cowling cover.

[whee]

While those two are choices, I wouldn't say that they are the only choices. You can also get a $10 peel and stick pad for the oil pan. But to Jon's concern I think they have fixed the issue of taking up the CHT wells by switching to the rocker cover bolt.

That’s right Jared! If forgot about that. Thanks.

I didn’t want to go off an a tangent and mention other systems. I figured Rod had researched and narrowed it down to those two. Of the two I still choose Reiff. I might put one on my plane if I ever get skis installed and do some winter camping. For keeping the engine heated all the time I like the twin hornet from aircraft engine heaters.

[jaredyates]

I will be installing a preheat system on my IO-540. Looks like the choices are limited, either Tanis or Reiff. The Reiff is somewhat cheaper. The main difference between the two is the Reiff uses a band around the base of the cylinder, while the Tanis uses a threaded plug that replaces a rocker cover bolt. The heating philosophy is different, Tanis says can remain plugged in continuously up to 100 deg ambient, Reiff says only use before flying. Would like to hear from builders with experience with either system.

While those two are choices, I wouldn't say that they are the only choices. You can also get a $10 peel and stick pad for the oil pan. But to Jon's concern I think they have fixed the issue of taking up the CHT wells by switching to the rocker cover bolt.

[whee]

Rod, I don’t mean to be “that guy” whom responds while lacking the experience you seek but if I may share my thoughts.

Whether it’s Reiff or Tanis the function of heat transfer is the same. I would choose the Reiff becuase I hate spark plug mounted CHT probes which are required when using the Tanis. I don’t think leaving either system plugged in all the time is a good idea. The daily ambient temperature swings will promote moisture inside the engine. A good insulated engine cover will help dampen the temperature swings so if your situation requires heat all the time then be sure to get a good cover.

[rodsmith]

I will be installing a preheat system on my IO-540. Looks like the choices are limited, either Tanis or Reiff. The Reiff is somewhat cheaper. The main difference between the two is the Reiff uses a band around the base of the cylinder, while the Tanis uses a threaded plug that replaces a rocker cover bolt. The heating philosophy is different, Tanis says can remain plugged in continuously up to 100 deg ambient, Reiff says only use before flying. Would like to hear from builders with experience with either system.