Hi ya'll,

It's me again with a brand new questions. Different people use different fuels with the different %age of Nitro. From 10% to 20%.

Question #1. Which fuel to be used for 2 stroke engine 10% 15% or 20% content of Nitro. (Currently I'm using 15%).

Question #2. Once we are done with for the whole day, and the last flight we took and brought the airplane down in one piece, what about the left-over fuel? Do we have to suck it back into the fuel bottle or do we just have to suck it outta of an engine and waste it? If we suck it back into the fuel bottle "the clean one" either 10% to 20% does it make any difference? as we are pumping the unburnt fuel back in?

Not to go into depth, Do we need to mix the unburnt fuel with the new fuel which is in the fuel bottle or not?

Thanks

Mody

Mody, you will get different views than mine on this one. Ilook at it like this, when you come back from the field, do you pump out your car's gas tank? Probably not. The differences are that the glow fuel will absobe moisture from the air and the nitro will evaporate off. That is in an open container. It will last a long time in a closed container. So, I have some little Dubro plastic fuel dots and at the end of the day, I pull the line off the carb and stick a dot into it, pull the line off the muffler and stick a do in it. If I'm going to put away a plane for a long winter nap, I fully fill the tank then seal it with the dots. That fuel is probably bettter after a few months than the half gallon jug stored for the same time. There is less air in the tank than the jug so less moisture.

Don.

Hi Mody,

Further to the advice from Campgems. No it won't matter if part of the fuel form the models tank goes back into your bulk fuel container. What is important is to run all of the fuel out of your motor to ensure there isn't any residue of methanol to attract moisture or nitro to start corrosion. When your finished for the day hook up your glo driver and at a fast idle run your motor until it runs dry.

Cheers,

Colin

Campgems, Crash Campbell,

Thank you guys for your great advices. I'm gonna do it that way either suck it back into the fuel can or burn the rest up.

MOdy

i suck the fuel back into the jug, less chance of spillage later.
as for nitro %, 0% works, 5% is plenty, anything above wont do much besides give you a few rpm and empty your wallet.

The methanol evaporates, not the nitro. Nitro is thicker, takes longer to evaporate, and harder to ignite than methanol.

After my flying is over for that plane, I usually disconnect the fuel line from the carb then run the engine dry. Then I drain the tank, putting the fuel right back into my fuel bottle, then I use a short length of brass tubing and connect the pressure line to the fuel feed line to form a loop. That keeps the outside air out and prevents any left over fuel tht the clunk may not have picked up from getting all over everything. There is usually an ounce or so left over in the bottom of the tank that may come out.

As far as nitro content is concerned, whatever works.. works. I usually pick up 15% nitro because that's what's generally available and runs just fine.

CGr.

I also drain the fuel out of the tank after a day of flying. Now more than ever since my plane needs to be stored with the tail up and the engine to the ground. As for what fuel to use. I have used 5% with all my 2 stroke engines and it works just fine. I feel more than that on a 2 stroke engine is a waste.

In answer to your fuel question. During cold weather 15% is easier to start the engine. during the summer time 10% is all you need. the higher nitro may give more power if you need it. Some 4 strokes love hi nitro, but then again it depends on what you want from the plane. Dennis

Thank ya'll for your great suggestions.

As everybody knows that heat of Texas gets nasty and summer is stomping at our doorstep. Temperature has started hitting 80F but lately it's pleasant. As winter is trying it's utmost to give us after shocks and lil bit chill factor is still here until April. But anyway, in summer heat, best bet would be 10% and yes I have not seen 5% at LHC where I buy my fuel. I think I'm gonna stick to 10% for summer.

One more question I'd like to ask back in my home country not my present country USA, we used simply 80% methanol 20% castor oil, there is a particular name for it I forgot and that's combination I read here at rcunivers is used in UK as well. There is a concept that if you used nitro regardless 5% upto 20%, it makes your engine work up and the engine's life gets cut short than the regular life span as it runs higher than it's capacity. I don't believe Nitro in anyway reduces the life of engine makes it do more than it's capacity. Do you think is it true?

Mody

Pump the fuel back into your jug, Once the fuel tank is empty, start the engine again till it dies out to get any fuel left in the lines/carb out. Personally, If I dont plan on flying that plane/engine again within a week or so, I then use Air Tool Oil/After-run to lube the bearings and keep rust away being the RC fuel attracts moisture.

I don't usually pump the leftover fuel back into the jug. Most of the time it's a couple of ounces at the most...so I leave it. The fuel in the tank is exposed to air, muffler sludge, vapor, etc...I keep that out of my jug.

The fuel left in the tank mixes with the new fuel next time you fly..just my preference.

Agreed.

There was an article not too long ago in one of the RC magazines that went into Nitro usage versus engine size.

The bottom line is that you are merely wasting money using more than 5% nitro on engines larger than .60 up.
On engines smaller than this more nitro was found to help... e.g. 10% for .60 down to .46's, and 15% on smaller engines.

Up to the point I read the article I was using 15% and 10% on my 1.20 through 1.80 engines. I glad I read it, as I then switched to 5% without a single hic-cup. I may have adjusted the engine by a click but that was the only change.

Given the difference in the fuel prices for lower nitro fuels, I was quite happy with the results.

I now run 5% on my O.S.'s, Saito's, GMS's, Tower Hobbies, SuperTigre, Magnum, ASP and K&B engines.

Note at higher altitudes your results may vary...

I haven't noted any differences in temperatures down to 50 degrees F, but I tend not to fly at temps below this.

Well,

That's a good idea as well. The engine I'm using at the moment is Evolution .45 engine which comes with Hangar 9's planes like PTS trainers. This engine has bushing no ball bearings. So the exercise what ya'll do with the fuel, does it apply to the all engines whether bushing or ball bearing either way it's fine?

High nitro does not make an engine easier to start in the winter, however it does make it easier to tune and with lots of cold dense are the engine runs better with the rich mixture nitro requires. To make the engine start easier you add gasoline or naptha to the fuel.

At the time of summer I need to use 10% Nitro and add gasoline or naptha to fuel? Thats what you mean? How much do we have to add gas or naptha?

Why would you need to add anything?

The PTS runs well with 5%-10% and does not really need more Nitro unless you are at high altitudes.

Once you've fixed the limiter problem and tuned it properly it should be a breeze to start, even when cold!

No for cold weather flying, freezing cold. But the gas is not absolutely necessary.

Well, I'm gonna finish this 15% gallon then I'm gonna switch to 10%. As in future I'd be using .60 size 2 stroke engine max. I'm not prepared technically & financially for .90 2 Stroke engine or Saito's 4 stroke engines.

Mody

just a thought, but if you run the fuel back into the jug after flying, you should have a good filter. There is a lot of gunk that gets into a fuel system.

I deadstick in everytime, so I know the tank and engine are empty....its just one of those things every body does differently...I'll be wiping down my plane while a flyin bud is pumping his tank empty...but then he fires it up to run out the fuel in the engine...I run mostly small stuff at %25 nitro....it goes in everything from .010 up to .15, after that I drop to %10-15 for upto .65 saito...Rog

I always drain my fuel after each day of flying, run the fuel out of the engine then a couple drops of after run oil. hook both lines together with copper tubing because I hang all my planes by the tail! We are at 7000ft here so I found that 15% gives me a little more power. But do use a filter when putting it back in the jug.

I used to burn up the whole fuel until plane gets a dead stick with my high wing trainer, that was my old practice, but in here specially with P51 Mustang, I can't do that it's a pretty good risk. So I ain't gonna do that. How about %age of Nitro, does nitro wear out the engine's life span or not?

Actually that is not true... quoted from Horizon's web site...

"Evolution Trainer Power System: A

Key Features
- Preset SetRight needle valves guarantee easy starting and great performance
- Canted glow plug tilts glow driver away from propeller during starts for safer operation
- No tuning, running or break in needed
- Ball bearing-supported crankshaft
- Includes muffler"

one of the best after run oils is............remenington spray gun oil. avail at wal mart. shoot it right in the card. not to much, just a squirt does it. other oils are too thick and coagulate in the glow plug. four stroke owners just put a squart in the breather tube at the bottom and flip her over a few times. nitro doesn't corrode, it's the moisture that the methonal draws that can rust bearings etc.........RON