BT00561

My Feedback: (26)

Cold weather which Glow Plug? Iwent out to fly the other day and it was a bit cold, probably in the mid 40's, Iwent through 2 glow plugs and didnt get a full flight out of either of them. The died about half way through flight and where done for! Ihave been using Fox Hot plugs with idle bar, far over a year and havent had any issues out of them unitl now. What do you guys use for your glow plugs when the weather gets cold? Idont remember having any issues last year when it started cooling off.

1QwkSport2.5r

I've ran engines on a test stand when it was 20°F outside here in Minnesota. I used to use SIG fuel with 20% oil which is 50/50 castor/synthetic and also my homebrew 20% all castor. No problems hot or cold weather, using McCoy MC59 plugs all year. Engines are harder to start when cold, but otherwise run fine. Unless you're running baffle-piston'ed engines, I wouldnt bother with an idle bar plug. I dont think idle bar plugs are hot enough. I've tried a Fox Idle bar hot plug in 3 of my engines and none of them will run on it without glow connected. Engines I tested were K&B Sportster .65, Super Tigre S90K, and Thunder Tiger Pro .46. The MC59 plug outperforms any other plugs I've tried by 500rpm or better.

mike109

G'day

There is an old saying in car racing circles - "cold and wet, bigger jet". Or in other words, in cold weather you need a richer mixture. You should not need to change the plug if it works well the rest of the time but you probably should make the mixture richer. Lots of burned plugs is usually too lean a mixture.

Mike in Oz

rcdude7

My Feedback: (264)

What type of failure are you talking about here?

378

My Feedback: (4)

I'm with Mike. I've never in seven years of running glow had to change plugs just from seasonal temp shifts. My cars run the same OS 8 in the snow as they do in those horrendously humid 105º southern summers, and have done for years. My plane, too, runs an OS8, and it will continue to do so when I fly in winter.


Fatten the mix up and it will stop burning plugs out. Every engine needs to run richer in the cold than the hot. Every engine. Even the one in your car. Our RC engines simply don't self-adjust for that, so they'll lean out unless we step in and do it ourselves.

Mr Cox

The cold it self cannot ruin the plug, so it sounds more like a general tuning problem that glow plug problem. 40°F is not that cold, but there are several things happening, there is more oxygen in the air, the fuel runs a little thicker (especially with all castor fuel) and the engine runs colder etc.

The two first reason means that the needle should come out while the third may wrongly indicate a too rich setting. My guess would be that you have a little more nitro than needed for the compression setting and that the engine was running on the lean side, hence blowing the plug. Unless you're doing competions there is no real reason for tuning that close to plug faliure. So add a head shim or two or reduce the level of nitro (use a tach before and after to monitor the changes in performance). When it is actual cold, around freezing or below, you can wrap something around the cylinder to help keep the temperature up, but I don't think that was your problem here.

iskandar taib

My Feedback: (5)

Cold air is dry and dense, so the engine will be gulping more of it. Hence the advice to richen up the needle. Once the engine is running I don't think the cooler air would make the engine run cooler, unless it's a very small engine.

For quicker starts, try a drop or two of Ronson cigarette lighter fluid in the intake. We used to squirt it in the exhaust for quick starts when flying Combat in the snow (the annual Frozen Finger contest, held the first weekend of the year IN CHICAGO). The engine kicks back something fierce when you turn the prop over, even when air temps were sub-zero.

Iskandar

378

My Feedback: (4)

It can and will. The colder air can remove more engine heat, which means if you don't wrap the head you won't warm it up enough. It's real bad with cars, sometimes in the dead of winter they'll get so cold they lock up entirely despite being run WOT through a combination of large, multi-fin cylinder heads and absolutely frigid ambient air. The sleeve contracts so much that the piston sticks in the pinch, and that's it. Not running any more, and sometimes it takes a rod with it.

Wrapping the heads is a given when running glow cars in the snow, I imagine it won't hurt aircraft engines either.

BT00561

My Feedback: (26)

I have some OS #8 plugs also and I run them in a couple of my engines. We only flew one plane the other day when we had the issue. I havent flown any of my planes in the winter time, since i usually go overseas for the winter, so this year is a first. I have had plug go bad from running it to lean, but didnt think about it the other day since a couple days before all the engines ran like a champ. So I will richen it up and give her another shot. Thanks guys for all your inputs. I really appreciate it!

ArcticCatRider

My Feedback: (6)

I've ran airplane and car motors in sub-zero temperatures. The kind of cold where your snot freezes upon the first inhalation through the nose.

I have never had a problem with fuel or glow plugs, nor have I made any changes other than needle settings to accomodate cold.

1QwkSport2.5r

+1. I always use the same plug brand, and usually start the engine and warm it up. After a minute or two, the engine will tell you through a variety of ways if it needs more fuel or not. Just gotta listen to it.