When is it too cold for Diesel fun?

[frank mccune]

     Hello:

     When is it too cold to attempt to run Diesel engines?  If I recall, Diesels do not like to start in cold weather.  What is the minimum temperature that one should make an effort to enjoy his Diesel engines?

     Tia,

     Frank

     

[Motorman]

55f

[Steve Lotz]

I have started them in the high 30's.

[frank mccune]

     Hi All:

     Thanks for the. 

      Steve, kindly tell us about starting drill for cold weather.  Without preheating the engine, I think one would have very little fun attempting to start a Diesel engine.  I have run glow engines in -25F temps, but that is a different kettle of fish. My 1972 Fox .36 performed quite well at 0 degrees F.  Again, it was a glow engine.

        Stay well,

        Frank

[John Park]

I've flown diesels plenty of times with snow on the ground, but I won't pretend it's an easy or pleasant experience. Mind you, it's only ever the first start of a flying session that's been a problem in those conditions.  You just have to be careful not to over-choke it, then flick as hard and fast as you can until you get a response.  This can take some time with a stone-cold engine.  If it kicks back (I once had my thumbnail ripped off!), you've over-choked it: back off the compression a quarter-turn, and keep flicking.  Small diesels, up to 1cc., are the worst unless they're fitted with a spring starter: 2.5cc and 3.5cc, especially ball-race engines, aren't quite so bad.

[Trostle]

     Hello:

     When is it too cold to attempt to run Diesel engines?

     Tia,

     Frank

It is too cold when your fingers cannot move anymore.

Keith

[Steve Lotz]

Try to keep the fuel warm as possible-leave it in the car until you are ready to fly. Then vigorous prop-flipping. I didn't have too much trouble with a Silver Swallow 2.5 diesel and it was in the 30's temp-wise. As an aside, don't ever run one of those without cleaning it first. I found a big chunk of swarf up inside the piston on mine.

You might want to increase the ether content in cold weather.

[FLOYD CARTER]

My diesel tractor has glo plugs for each cylinder.  They are used just for starting.  But maybe that would not be practical to add a glo plug in a diesel model engine.  It gets cold in Oregon, but my Elfin 1.8 starts OK after a few "burps" to get warm.

[frank williams]

My son holds the Jr and Sr cl endurance records.  We used a Webra .15 diesel.  On the Jr flight attempt (45+m) there were puffy clouds about and periodically the sun would be behind the clouds and the flight not in direct sunlight.  We had the leanest setting I thought we could afford and the exhaust was blocked with a large wirewrap around the radial exhaust.

After a while of flying we noticed it was going lean and loosing power.  My son was struggling to stay up.  But then the sun went behind the clouds, and miraculously the motor picked up and ran strong.  That pattern continues for the rest of the flight.  Sunny,lean .... Cloudy, strong and powerful.

The radiant heat from the direct sunlight is enough to make a difference in the run of a diesel .

[Dennis Saydak]

When I was sixteen (a long time ago) I used to use model diesel fuel to prime glow engines when the temperature was as low as -15F. They always started. We had a warming shack near a school yard skating rink to warm up in between flights. Ya those were the good old days. Now I fear venturing out at much warmer temps.   

[Motorman]

My son holds the Jr and Sr cl endurance records.  We used a Webra .15 diesel.  On the Jr flight attempt (45+m)

That was with the old 4oz tank rule, right?

Motorman

[John Park]

Sunny,lean .... Cloudy, strong and powerful.

Or possibly: Sunny, engine running hot, which diesels don't like... Cloudy, engine running cool and happy. 

[Steve Helmick]

This may be only my opinion, but I'd say 125F. I've had a bunch, ran most of them, and didn't enjoy the experience. Smoke 'em if you got 'em...meaning if you like them, help yourself. Same goes for electrons, OBTW.  Steve 

[frank williams]

Old 4oz rule for endurance .....yes

[john e. holliday]

As we learned flying F2C racing if lean, lead the airplane and if rich hold back on it.  Humidity had a lot to do also as we learned flying at Buder Park in St Louis at our first team trials we competed in.  I think Lake Charles was the worst for us.   Now I am trying to relearn all I have for gotten about diesels.

[Paul Smith]

That was with the old 4oz tank rule, right?

Motorman

In the ORIGINAL CL Endurance, it was 4 pounds of airplane with fuel, which resulted in all-day flights.
I was the author of the 4-ounce fuel rule.  I did 28 minutes with a stock G20/15 diesel.  Later on, guys fiddled the 15 diesels to the point where they took pretty near all day too.
The Endurance records were then cleared again when a 1-ounce fuel rule superceded the 4-ounce rule.
I'm not sure if AMA still carries this obscure event.

[Motorman]

Speaking as the current record holder yes, they still carry the event. I would still be active but good ether is a zebra unicorn these days. 

Motorman

[Paul Smith]

Speaking as the current record holder yes, they still carry the event. I would still be active but good ether is a zebra unicorn these days. 

Motorman

Thanks to Richard Pryor.

[frank williams]

Walter ... AMA still list Jr and Sr with my sons 4oz flights and yours, with a one ounce, with no distinction between the three.  I think they are unaware of the rules change.
https://www.modelaircraft.org/sites/default/files/events/Records/National_Records_Listing_04062022.pdf
Frank

[Dave Moritz]

Hello all:

Any idea what drives the seemingly high prices for diesel motors on E Bay? Every now and then, this bottom feeder likes to snag a deal on flyable IC engines, but the low-end diesel trough is always empty. Is anyone flying those engines?

Dave Mo…

PS
Well, the trough is not always empty - I did get a very nice KMD 2.5 for a sane price.

DM…