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General control line discussion => Open Forum => Topic started by: Russell Shaffer on November 28, 2006, 08:51:57 PM

Title: Minimum glow temperature
Post by: Russell Shaffer on November 28, 2006, 08:51:57 PM
Does anyone know what the minimum temperature is for glow engine operation?  Just curious, as I'm sure it is cooler than I would want to fly at.  There has to be a minimum temp at which the glow plug/methanol cycle will work.  If it won't vaporize, it won't burn.  Heating the cylinder with a propane torch doesn't count.
Title: Re: Minimum glow temperature
Post by: john e. holliday on November 28, 2006, 08:59:11 PM
John Bender and I have flown when the temp/wind index was in single digits.  Need good hot battery and fresh fuel.  An electric finger helps also(electric starter for those that don't know).   DOC Holliday
Title: Re: Minimum glow temperature
Post by: Steve Helmick on November 28, 2006, 09:04:40 PM
From personal experience, I'd guess something under 20ºF. See the thread on Snow Flying Stunters. Things would be a lot better now, since invention of good batteries, electric starters, and synthetic oils. Just letting the engine warm up in the car would help a ton, as would having batteries small enough that you could put them into a warm pocket with one of those chemical hand warmers. Insulated pack boots, polar fleece and a Filson hat would have come in real handy, that day. I have all that warm stuff now, but I'd still be cold.  ~^ Steve
Title: Re: Minimum glow temperature
Post by: RC Storick on November 28, 2006, 09:09:00 PM
Remember this at 32F the battery looses 50% of its cold cranking amps. So a 1.5 volt battery is the equivalent of a .75 volt battery. The colder it gets the more it looses.
Title: Re: Minimum glow temperature
Post by: john e. holliday on November 28, 2006, 09:15:58 PM
Hey, Sparky, I remember it was showing 32 degrees on the temp gauge on the old Ford when we backed in at Buder last February.  Must have gotten into the 50's that afternoon as the gauge was showing 48 when we headed home.  Emmy is still sleeping with that trophy she picked out that day.  Watch out as she is now doing wingovers and loops.  DOC Holliday
Title: Re: Minimum glow temperature
Post by: Keith Spriggs on November 28, 2006, 09:17:30 PM
When gas was 25 cent a gallon we used to hold the engines at the tail pipe of the car to warm them up. Didn't know enough to hold the battery there.
Title: Re: Minimum glow temperature
Post by: Bob Reeves on November 29, 2006, 03:09:42 AM
Remember this at 32F the battery looses 50% of its cold cranking amps. So a 1.5 volt battery is the equivalent of a .75 volt battery. The colder it gets the more it looses.

Being pickey, the voltage doesn't decrease just the amount of time the battery can deliver x amount of current at full voltage.
Title: Re: Minimum glow temperature
Post by: dave siegler on November 29, 2006, 07:38:42 AM
As a teenager,  I would often fly RC at temperatures into the single digits on a frozen lake.  A good battery is a must.   I used a little lighter fluid for a prime.  The first start is a little tough.  Motor runs well when it is cold, no issues with low speed either.  Some guys block the fins with al foil to keep the heat up. 

Dave 
Title: Re: Minimum glow temperature
Post by: L0U CRANE on November 29, 2006, 01:58:09 PM
Ran a meet in February 1975 in Omaha.

Temps started in the low/mid 20°s and got up near freezing at the "warmest".

Most fun, other than trying to survive, was that the lines melted into the ice before takeoff. We've all seen or heard how wire will sink through a block of ice? It happens.

Start, go to the handle, rip the lines up through the ice, take off and be ready for the damp lines to re-freeze together. Made controls a bit stiff and 'crunchy?'

Racing events were "remarkable" to say the least.



Been there. Done that. Moved to Arizona...
Title: Re: Minimum glow temperature
Post by: Willis Swindell on November 29, 2006, 04:50:21 PM


I remember one saturday morning a few years ago at the King Orange in


Florida The temperature was 27 degrees with a 15 mph wind  and some one banging on my car window saying it was my time to fly.
Willis  %^
Title: Re: Minimum glow temperature
Post by: Russell Shaffer on November 29, 2006, 07:55:54 PM
27 ABOVE?  That doesn't count.  It was 2 above in Oregon this morning.  No, I didn't even think about flying.