Ok guys here is the deal, im not too happy the way my st g51 is running in midrange even when it was warm, its annoying. i run omega 5% med hot os plug and its tuned to as good as it will get trust me. its on an avistar. so a couple of things here, it wouldnt run worth crap in the 30 degree weather. ive heard of people running them in the cold.

does anyone have problems running nitros in the cold? mine just dies constantly and is hard to start.

also pleas give me a couple of engines that AREPROVENto have NO midrange or any tuning problems, i really need an engine that has a nice proven carb unlike the st g51. i know some will tell me that its a fine carb, well its not for me. are magnums ok? i dont know i want to fly in the winter time

The ST 51 carb is as fine a carb as there is. Your engine is likely to have a rich midrange with some other carb?

The fuel nipple is normally turned towards the front mounting bolt. Raise it slightly

Run a hot plug

Try a 11 X 6 prop

A Perry Carb? http://www.perrypumps.com/prod01.htm


<font face="ARIAL">Super Tigre .51</font> # <font face="ARIAL">1400

People seem to like them</font>. Most aften all you need to adjust is the High speed needle.

$39.99 http://www3.towerhobbies.com/cgi-bin...XDG44&amp;P=ML

Here's a trick for flying in cold weather:
Wrap heavy aluminum foil around the cylinder, starting just above the exhaust stack up to and including the head.
If you can get Propylene oxide, put one ounce per 100 ounces of fuel. Do this just before you fly. It's great for cold weather starting and idling.The propylene is very volatile and easily escapes from your fuel. Take care not to get it on your skin or clothing. Propylene oxide is a probable human carcinogen.

Propylene oxide is an organic compound with the molecular formula CH3CHCH2O. This colourless volatile liquid is produced on a large scale industrially, its major application being its use for the production of polyether polyols for use in making polyurethane plastics. It is chiral epoxide, although it commonly used as a racemic mixture.

This compound is sometimes called 1,2-propylene oxide to distinguish it from its isomer 1,3-propylene oxide, better known as oxetane.

Sounds like a good drink mix, Vodka and whatever you said

Not an expert by any means, but I do fly in 30 to 40 degree temps a lot. Here's some tricks I use:

Take an inverter and hair dryer with you and heat the cylinder and head of the engine just prior to starting.
Run a hotter plug like an A3, maybe even one with an idle bar.
Set the HS mixture a click or two richer than normal and run the engine full throttle for 10 or 15 seconds, then return to proper setting and run full throttle another 10 to 15 sec before trying to take off.
Keep your throttle at 1/2 or more during flight and run it to full throttle now and then, don't try to idle or cruise the whole time, keep the rpms up and the engine is warmer.

I've never tried running 5% nitro fuel, I use 15% omega and it's worked fine for me. I also add a couple onces of Klots per gallon, but I wouldn't say this helps any in the cold, doesn't hurt though as long as your not storing the fuel in freezing temps also.
If you are, it might help to bring the fuel inside the night before you try to fly.

I run O.S 46 and Magnum xls .46 in cold temps all the time. I run 11 x 6 prop on mine also. I know the .51 will spin a bigger prop, but a smaller one will also force the rpms to run a little higher than usual which will help the engine stay warmer and might help U past that midrange problem.

Hope this helps, good luck

I fly in below 0 degree celcius and I use a small torch to preheat my engines (not cowled) and they start as easy as in mid summer. Set the needle and fly, no problems whatsoever.

mix some small amount of gasoline in your 5% fuel for ease of starting the engine without preheating in cold environments.

Hi!
How much is 30 degree Farenheit in Celsius??? I have run Italian Super Tigre engines at -10-15 degrees Celsius without doing anything besides setting the needles.
Most likely your Super Tigre running needs a low speed adjustment.
There is nothing wrong with a Super Tigre carb or with any other carb on the market and using 5% nitro fuel is perfect for it.

But...To have it run good you follow some simple rules, besides setting the low speed needle correctly.
1. Follow the tank position rule.
2. Use a 300cc tank
3. Use a OS 8 or Enya 3 glowplug.
4. Use a 11x6-13x4 prop. RAM or APC, and balance the prop.
5. Use a Uni-flow tank set-up.
6. Place the tank as close as possible to the firewall.
7. Use an aluminum spinner nut instead of cheap plastic spinner.

30 F = -1 C, about.

32 F = 0 C

I live over the mountains from you and believe me, 30° isn't cold with regards to glow engines. We regularly fly in temps MUCH colder than that without problems. Here's a couple suggestions in addition to the ones already offered.
Use fuel with a higher nitro content. Smaller engines generally perform better with more nitro, try 15%
Re-tune the engine, colder weather often dictates a richer mixture
If it's still hard to start, put a couple drops of cigarette lighter fluid into the carb before you start it
Try a OS #8 glow plug
Oh, did I mention to use fuel with a higher nitro content, nitro is your friend
There's no reason at all that your engine shouldn't run great even at temps into the lower teens

Just tune the engine, cold air is very dense.

Quote:

ORIGINAL: flyinbence

OK guys, here is the deal, I'm not too happy the way my ST G51 is running in the mid-range, even when it was warm. Its annoying. I run omega 5% med-hot OS plug and it's tuned to as good as it will get; trust me. It's on an Avistar. So a couple of things here, it wouldn't run worth crap in the 30° weather. I've heard of people running them in the cold.

Does anyone have problems running nitros in the cold? Mine just dies constantly and is hard to start.

Also, please give me a couple of engines that ARE PROVEN to have NO mid-range, or any other tuning problems. I really need an engine that has a nice proven carburettor, unlike the ST G51's. I know some will tell me that its a fine carburettor. Well, its not for me. Are Magnums OK? I don't know. I want to fly in the winter time.

Flyin'


First of all, it is not 'a nitro', nor is it a 'nitro engine'...

It is a glow engine (see the name of this forum) and nitromethane is just an additive, which all glow engines out there could be set-up to run without.


Some low compression engines, designed for the north American market, will benefit from the addition of nitromethane to their fuel, but that will not transform them into 'nitro engines'... The ST G51 is not one of those and your using 5% Omega (which is right for this engine) attests to it...


'Nitro engines' only exist in nitrous-oxide car wannabes' dreams.

Also, as you predicted, the ST carburettor is not only 'just fine'; it is one of the best out there, allowing a separate adjustment of the mid-range fuel-curve.
It is a bit harder to adjust, compared to a simple two-needle; requiring the nozzle retention bolts to be loosened, to get to the mid-range facility.

This is also another thing that could fall out of adjustment, making this chore more tedious.


But if you do set your mind to it; if this carburettor is adjusted perfectly, your engine will run better than with any simpler carburettor, adjusted to its perfect state.


Regarding nitro; adding more of it to your fuel, in cold weather, *will* make any engine run better; even your run-of-the-mill glow engine.

OK, time for me to ask a question. I read this all the time about how nitro makes an engine start better in cold weather but because I never use nitro or experience what you guys call cold I've no way of knowing. What makes me wonder about the truth of this is that nitro has a flash point of 35C while methanol is 11C so I would have thought that methanol would be easier to ignite because of the heat generated inside the cylinder due to compression when starting the engine. What am I missing?

Ronson lighter fluid has a flash point of 42F or 5.6C and it will start one off immediately

Quote:

ORIGINAL: downunder

OK, time for me to ask a question. I read this all the time about how nitro makes an engine start better in cold weather, but because I never use nitro, or experience what you guys call cold; I've no way of knowing. What makes me wonder about the truth of this is that nitro has a flash point of 35°C, while methanol is 11°C. So I would have thought that methanol would be easier to ignite, because of the heat generated inside the cylinder due to compression, when starting the engine. What am I missing?

Brian ,


You're the expert on fuels and what you say is true...

However, it could be that when the intake air temperature is lower, an engine can tolerate fuel that would normally (i.e. in warm weather) require a lower compression ratio...


This makes fuel with nitro 'more appropriate' for cold climates...

The problem that bothers the thread opener seems not to be getting the engine to fire; for which the higher volatility of methanol would be a better remedy (but it is already there)...
It is getting the engine to continue running reliably, for which the 'appropriateness' of the fuel is probably the more desirable attribute.


Perhaps this is the quality he needs.
...And perhaps, the Chinese ST engines have a lower C/R also; making nitro more desirable than it was in the older Italian made engines...

it will fire up just a bit hard, but thats not the main problem. i dont think 15% will make it run a whole lot better than 5%. i dont know it just wouldnt stay running, just kept cutting out even with tuning. another problem is, and im not sure how big it is, i cant re locate my fuel tank, in the avistar its in a fixed spot. the centerline of the tank is lower than what st book calls for compared to the high speed needle. i called a guy from a hobbytown usa and he said not to run any glow powered engine under 40 degrees Fairenheight. but people here say they run them in much colder weather, this sucks, the engine has 1 gallon thru it and its broken in. just not too long ago when it ran ok when it was warmer but still had the midrange problem if i left the throttle just under half and let it sit there.

does anyone use pumps for there carbs on glow engines, or is that not needed.

Hi!
Let's settle one thing first!
5 or 15% nitro isn't going to revolutionize your engine starting. However 5-10% nitro will make your engine run better and slightly improve engine starting once you know how to start a glow engine.
But first you have to use the right starting technique.

1. Use an electric starter....I know that flipping prop by hand is one way of doing it, I learned that way myself, but an electric starter will make starting easier.
2. Use adequate battery power...that is 12V, 10A motorcycle battery and a automatic glow-driver. Never ever trust a small 1,2V NiCad igniter, they have not enough power when cranking a hard to start engine.
3. Have the tank placed according to the tank rule...and do use a Uni-flow set up with two clunks.
4. Use an aluminum spinner nut...Not a cheap plastic spinner.
...Then start your engine at idle...this means having the throttle open approximately 2mm open from fully closed.
As soon as the engine has fired, fully open the throttle and adjust the engine for slightly rich setting with the high speed needle. That's it!

...A pump is not needed!!! (or wanted). It's all about starting technique.

Call the guy back at Hobbytown USA and tell him he doesn't know what he's talking about.

I've run glow engines in -20 degrees Faihrenheit. I'd be out of flying 1/2 a year if I didn't run them in under 40.

It sounds like you have other issues to sort out before thinking about a pump, or a midrange adjustment. The fuel tank can be lowered...it will just require additional effort. Or, the engine mount can be moved up or down. The options are limitless.

Uniflow, and electric starters are just two of those options. I've never seen an avistar with a uniflow set-up, and I haven't used an electric starter in a long time.

Have you taken the carb apart? Is it clean? I'd check stuff along these lines before I started to lower a tank, or add a pump, etc.

I don't think its easier to start with more nitromethane, but it does have less cooling from evaporation. Also engines lose timing in cold weather because the mixture is colder. So more nitro advances the timing and improves running. Also a wider mixture range making the engine easier to tune in a tricky environment. A hotter plug and slightly more nitro would help. But lots of nitro might make initial starting more difficult.

He is able to get the engine to fire, so more nitro may help prevent the engine from cutting out, make it easier to tune. But he will have to richen the mixture. But then again the cold air means you will have to.

Ditto everthing Sport Pilot said. But would like to add that those above who reccomend the OS #8 have most likely not used it much in cold weather. The #8 is a COLDER plug than the OS A3. The #8 will last longer, especially in the summer, but the A3 is better in cold weather.
I also fly a lot in cold temps. Its been 20 to 30F here all week and I've flown a tank of fuel thru my new SPAD with .45 Super Tigre and a tank and a half thru my Avistar with Magnum .46 xls. at 29F. About 30min was all my fingers could stand in the thin gloves I had.

I think a lot of the posters here have missed the fact that he didn't have trouble starting the engine, he had trouble keeping it running.

The OS A3 or Enya #3 should help a cold natured engine.

Glow engines generally do not start easily below 50F

I've never changed glow plugs based on colder weather...just the needle setting.

If I may, since you list Jefferson as your location, I would suggest you drive over to Corvallis and go to Trumps Hobbies. Take the plane if necessary. They can get you headed down the right path. Additionally every year on Jan 1 there is a Polar Bear fly at Adair. If your not doing anything on the 1st you might head over there, it's just North of Corvallis. There will be plenty of help there. Nothing like having someone actually show you in person. FYI Trumps has been around for years and is staffed by people who know RC inside and out. Just ask for Jim or Jim.