Cold weather operations for two-stroke self-launchers?

Can anyone with experience self-launching in cold winter conditions share germane experience? Any specific concerns or issues operating an air-cooled, two-stroke at, or near, freezing temps? Any experience with carb icing? Any deal-breakers? Any tips? Contemplating occasional winter flights in the Northeast, self-launching with a Rotax 505. Thanks!

Provided you study the operating manual and comply to any specific indications above all, in my experience the Rotax 505 allowed me to fly during the winter in northern Italy (take-off at little more than 0°C), and I was once able to go see the panorama from 5000 m AMSL with no problems (estimated 25°C below Zero). Of course the engine was producing reduced power and climb at altitude.
Starting the engine when cold-soaked after a prolonged wave flight is probably more trouble prone, but still possible. Battery performance matters, as well as engine conditions. Generally, having used the engine for self-launch or a test-run a few hours before, allows it to be still that little warmer and start more "reliably". Apply power progressively. Generally, less than a minute is enough, the engines have a small mass and warm up rapidly.

Currently I own a watercooled two-stroke SLG, and the manual mandates to warm the engine to 40°C before take-off. Takes maybe less than a minute while checking circuits and emergencies.

Aldo Cernezzi
www.voloavela.it

I've been flying my DG800A with Rotax 505 in the cold weather of central PA recently and have the following recommendations. 1. Bundle up, rigging in the cold can be brutal. 2. Expect the batteries to lose charge more quickly, and for the engine extension/retraction to go a little more slowly than normal. 3. If CHT is below 0 Celsius before cranking, use the choke to start more reliably. 4. Read your aircraft manual regarding cold weather operation; some gelcoats may crack in extreme low temperatures. 6. If there is precipitation, make sure to check all your static ports/leading edges for snow and ice accumulation.

On Tuesday, March 7, 2017 at 8:44:00 PM UTC-5, Paul Villinski wrote:
Can anyone with experience self-launching in cold winter conditions share germane experience? Any specific concerns or issues operating an air-cooled, two-stroke at, or near, freezing temps? Any experience with carb icing? Any deal-breakers? Any tips? Contemplating occasional winter flights in the Northeast, self-launching with a Rotax 505. Thanks!

A squirt of campfuel or ether (quick start) greatly helps
start up.

JMF

On Wednesday, March 8, 2017 at 11:09:17 AM UTC-8, firsys wrote:
On Tuesday, March 7, 2017 at 8:44:00 PM UTC-5, Paul Villinski wrote:
Can anyone with experience self-launching in cold winter conditions share germane experience? Any specific concerns or issues operating an air-cooled, two-stroke at, or near, freezing temps? Any experience with carb icing? Any deal-breakers? Any tips? Contemplating occasional winter flights in the Northeast, self-launching with a Rotax 505. Thanks!

A squirt of campfuel or ether (quick start) greatly helps
start up.

JMF

Here's my preferred brand. After all, it is what you're thinking or shouting at the time.
Jim

http://www.nulon.com.au/products/Aer...Engine_Starter

Thanks for the input -- has anyone had issues with carb icing on a self-launcher? Not something I have ever given any thought to. Specifically in reference to Tillotson carbs on the 505. There may be some longer engine runs involved while ferrying 45 miles to the local ridge.

On Sunday, March 12, 2017 at 1:24:26 AM UTC+10:30, Paul Villinski wrote:
Thanks for the input -- has anyone had issues with carb icing on a self-launcher? Not something I have ever given any thought to. Specifically in reference to Tillotson carbs on the 505. There may be some longer engine runs involved while ferrying 45 miles to the local ridge.

I discovered my engines susceptibility to carb icing at about 400ft one cold winters morning, having spent the hour prior washing freezing dew slush off the wings. Who'da thunk it.

I'd assumed prior that it was all too tightly integrated for carb icing to be an issue.

And how did you handle it, turn back and land? Or resolve the situation in another way? Was engine performance compromised enough to threaten your safety?

On Sunday, March 12, 2017 at 9:17:43 AM UTC+10:30, Paul Villinski wrote:
And how did you handle it, turn back and land? Or resolve the situation in another way? Was engine performance compromised enough to threaten your safety?

The engine spluttered and stopped over about 5 seconds. I retracted the engine and did a very abbreviated circuit. My self launcher has a folding propellor and a single switch for up/down, it could have been a bad accident in a more complex self launcher (DG400 etc).