Thread: Engine preheat for cold mornings

Hi All,

Here is a Rotax link for an engine preheat system by Tanis. This should work very well for all of you that don't live in Arizona.
This is a video link and the system is easy to install.

http://www.rotax-owner.com/reviews/reviews.htm

Roger, I'm tossing all extra change into my piggy bank and saving for the Tannis heater. Until then, here's the way some of us CTer's in Michigan warm up our Rotax's on frosty days:

Your wife is going to be mad when she can't find her hair dryer. :P
Seems like you would have to leave it on for 3-4 hours and a hair dryer wouldn't last long at those run times.

Yup. I had to check with ground control to get authorization to use the hair dryer. What I don't show in the picture is my old quilted bedspread that I drape over the upper cowl. And....if this doesn't get the temp up, my portable barbeque under the engine! (just kidding about the barbeque).

Most days are 30+F. On occasion, we go below 0F and I just don't fly when it's this cold. I start the hair dryer going while I check out the plane and in 15 or 20 minutes at around 20F, the oil temp is up to about 50 degrees. I know that this is probably marginal but the hair dryer warms up all of the engine, including the battery. Most winter days here are 30+F. Adding a small 120 V. oil dipstick heater into the oil filter/reservior is another thing I might try and/or a 60w droplight in the engine compartment. This would be something I would just leave on overnite. The Tannis heater is the way to go and it is on the "wish list".

There's an error in the Tanis Aircraft Products Engine Pre-Heat System video presentation. At several points in the presentation they take a differential temperature in degrees C and convert it to degrees F on an absolute scale. For example, about 7 minutes into the video they say that with the Tanis system the average engine soak temperature after 5 hours was raised 15 deg C over the temperature without the preheat system. The graphic indicates that this is equal to 59 deg F. Although 15 deg C is 51 Deg F on the absolute scales, a temperature differential of 15 deg C is only equal to 27 deg F.
They make the same mistake again in claiming that a gain of 28 deg C is equal to 82 deg F, when in fact it is only equal to 50 deg F.
These errors result from forgetting that the zero point for the two scales is offset. You need to subtract 32 degree from the absolute Fahrenheit values to get the relative values. Alternately, you can calculate the Fahrenheit equivalent by multiplying the centigrade differential measurements by 9/5.
The frustrating part about this is that there is no means for providing feedback. There is no contact information on the Rotax-owner web site. I guess they don't want to hear about their mistakes.
I do appreciate their reviews anyway. They're useful and informative... although not perfectly accurate.
Mike Koerner

Hi Folks,

I found another error in the video. Look at 04:36. They do the torque test in the wrong direction

Not good for the electric starter and the brushes in there

A good example for real experts at work :P

Greetings
Markus

My concerns with the differential temperature conversions from Centigrade to Fahrenheit have been addressed.
Again, this was a minor issue. The video is a very informative presentation on what looks to be a great product.
The Rotax Owner assistance Network is doing a great service for us.
Mike Koerner

23F overnight in Dallas, just cold enough to warrant preheat. I used the HPS (hairdryer preheat system) this morning. Set it on high flow and low heat and measured 100F with a thermometer, not too hot so as to deform anything. Hairdryer was probably putting out 500W. Got the engine up to about 45F to 50F in about 40 mins, oil wasn't that warm, but the engine started right up - battery probably got a little heat as well.

We need preheat so infrequently here, temperatures are (relatively) mild and it's so inexpensive, a good method.

Doug

Also using the HPS on an auto timer untill we can get the Tanis installed. Works well for so little cost.

Just remember, using a hot air method it doesn't take long to get the cylinders warm enough for easy starting but it takes alot longer to get the oil warm. At 23 F and with us using non-aviation oil, it doesn't really make much difference. But, at some point temperature wise, not giving several hours to get the oil warmed up can't be doing the engine any good. Most of us probably won't be flying the CT when it gets that cold but for those who might, get that oil warmed up.