Is it ever too cold to fly?

[xcrmckenna]

Me, too.  That’s right where I usually run: 65%, 50 LOP, around 8.5-9.0 gph.  I curious what’s so bad about that...???

I would try 25 degrees LOP. My plane loves it there. I true out at 175mph speed and efficiency at that setting works for me. If I am flying above 10,000 I’m burning about 7.8 gph.


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[Shadrach]

5 hours ago, jaylw314 said:

That always puzzled me.  Why would lead scavengers care what your CHT is?  Don't they just care what your combustion temperature is?

They don’t care. Like many things in aviation CHT is used as a proxy. The temperature of the plug is what matters. Summizing the literature I’ve read on the subject, TEL and Ethylene Dibromide form Lead Bromide during  the combustion process. Lead bromide is a solid below ~700°F.  Without Ethylene Dibromide, TEL would convert to Lead Oxide rather than Bromide. Lead Oxide has a much higher (~1650°F) melting point.

 

 

[carusoam]

 

Sorta summary of some of the ideas in this thread....

 

•  

1) Lead scavenging is the process of keeping the lead from depositing inside the cylinders....

2) the process is temperature dependent....

3) we only have two temperatures that we can measure...  EGT and CHT...

4) Both temps are close but not a direct measurement of the interior cylinder walls or surface of the piston....

5) So we can use an observation like.... when my CHTs are kept above X°F I don’t get many lead balls in the lower spark plugs....

6) Many simulataneous things going on.... with cold cylinder temps...

• Tighter cylinder / piston relationship
• Lead scavenging becomes less effective

7) How dangerous or harmful?  That would take somebody reporting a loss of compression caused by high wear on piston rings after flying for hours at low CHTs... or reporting a cache of lead balls falling out when the lower spark plug gets removed... or finding them hiding in the exhaust pipe at annual....

8) Essentially this thread serves as a reminder that lower CHTs are a good idea, but not taken to the extreme of the good idea... 

PP thoughts only, not a combustion engineer...

Best regards,

-a-

[mike_elliott]

On 1/28/2019 at 10:22 PM, Marauder said:

 Packed!

 

 

List of ingredients:

 

2 Person thermal tent

Thermal blankets

Compass

Rain ponchos

50’ parachord

Water purification kit

Collapsing cups

Sleeping bivvy

Glow sticks

LED strobe

Fire starter kits (flint and waterproof matches)

Carabiners (lightweight & climbing)

First Aid Kit

Signal mirror, whistle

Camping stove

Portable stove gas

Camping pots

Hunting knife

Collapsing shovel

Folding saw

Hatchet

 

Food is brought on day of flight

PLB, flashlights, VHF radio in flight bag

 

 

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You forgot a watermelon, camp stove, 6 pack of Bud, fishing pole and extra toilet paper

[Marauder]

You forgot a watermelon, camp stove, 6 pack of Bud, fishing pole and extra toilet paper

The camp stove is already in there. Like the rest of the suggestions. Although I may need to slice up the watermelon to get it in there.


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[Shadrach]

On 2/16/2019 at 10:53 AM, NJMac said:

I finally was able to make the flight yesterday. Their C was nice and warm the whole way, took my winter jacket off and was comfortable in the cabin.

My E just wouldn't warm up. I ran it about 50 LOP and the CHTs were still sooo cold. Is this just now it goes when it's so darn cold?

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To your original question regarding cabin temps-  I would suggest you have a qualified mechanic inspect components of your aircrafts heater. I can think of no reason why your heater’s performance would be materially different from the one in my F model. Unblended heater air in my aircraft is so hot as to be intolerable by front seat passengers. I am surmising that you either have a blockage or a leak in your system. 

The next time I fly I’m going to point a laser thermometer at my heat vent. It will be interesting to see just how hot it will get.

[Ragsf15e]

Two quick thoughts... completely unrelated:

1. Cold flying at smaller airports... watch the snow vs wingtips carefully!  Snowplow drivers seem to also be high wing flyers in my neck of the woods!  I literally had to shutdown and shovel just off the runway once and couldn’t even get close to the cheap fuel I had actually come for!  Small airport, city plow.  

2.  Without getting into huge lop discussion, 50 LOP might be good at ~75% or 80% power to keep you out of red box/fin.  As power gets lower, box gets smaller and disappears ~65%.  So as Shadrack and Carusoaum said... at 65% power you can run much closer (or at) peak and get better performance while still lop.  At higher power settings (usually down low altitude), 50 lop might be more appropriate.