what is beter gas or glow and where do you get them?

Gas comes from 7-11 or QT, while glow comes from the hobby shop. Which is better depends on the plane you are flying. Generally, bigger engines (over 1 ci) go gas while smaller are glow powered.

better how? if you mean what is better between a gas engine and a glow engine, then maybe we can say the gas engine es less expensive since you can get the gas on any gas station and it costs less than glow fuel, but the engine itself is more expensive and needs more equipament than the glow one.

Please qualify your question?

Glow engines definitely have their place in model aviation and there are many options.

Gas engines also have their place. With the many new small gas-burners arriving on the market, airplanes of the .60-1.20 glow size can now enjoy the SIMPLE needs and economical operations of gas-burners.

I am no expert, but the way I see it, gas engines are more expensive but cheaper to operate. Glow (in the size up to 120) are slightly cheaper and more expensive to operate. I also noticed that the gas engines react later to the throttle input than glow, but that on my sim only. Havent yet had the need to get myself a gas engine as yet

Ameyam

Gas means you can go to the field with the model, your transmitter, a gasoline can with a pump attached and a heavy glove (optional but worth it if that 18" prop slaps your knuckles). That's it.

No starter, no glow-driver, no roll of paper towels and spray cleaner to deal with the mess after flying, no after-run oil, spark plugs last almost indefinately.

But they mostly come in larger sizes. Much easier to see in flight because of this.

Glow models can be cheaper, smaller, less intimidating, need less runway coming and going (not in all cases, though), less likely to cause a brush fire in the event of a hard dirt-nap in the weeds.

Note - if they react slower as noted above it is because of the inertia of the big prop. My 34cc kicks from 2,000 rpm to 7,000 rpm in a second. About the same time as a .46 goes from 3,000 to 15,000 rpm. Both are landing-idle to wide open. GAs turns bigger props but slower. Like an even more exaggerated difference from 2-cycle to 4-cycle glow engines.

My rule of thumb has been any plane requiring a bigger glow four stroke engine then the 1.20 then I would go to gas. Today nice gas engines like the DLE and CRRC are cheaper then a glow engine and you also save on the required field equipment needed to operate glow engines. There are now some smaller gas engines on the market and the cost is down on them too. I haven't used any so I can't report on them at all. Go to the gas engine forum to read what users have to say about them. Gas engines are simpler to operate then glow engines and require almost no servicing at all and aren't effected buy weather conditions, no needle twisting required once you have them in tune. It's a pilots choice but today if someone is just starting out in the hobby buying gas or electric isn't a bad idea. I have several gas engines but I have a bunch of glows so they get used more often in my planes. Go read up on the gas engines you are thinking about. There is no better, they both have there following, gas is easier and cheaper.

After purchasing a 1.80 glow four stroke engine, I discovered that Grey Beard's post is right on the money...

I do find that most of the less expensive gas engines tend to produce less power for weight and stated equivalent glow engine size ranking, than their glow equivalents, but otherwise the cost savings are much better especially as you move up in size.

e.g. a 20cc gasser is often stated to be a replacement for a 1.20 size engine, where I tend to find that you need to move to a 26cc gasser to get 1.20 glow output power levels.

Tuning is a bit different, but after dismantling and fixing several gassers for planes, I'll never look at a misbehaving weed wacker with ANY fear what-so-ever!

Gray beard 2nded.

Gas just makes sense. Its where I'm headed. Won't be purchasing another glow engine again. I really hate having to throw good toilet paper away after a flight...

Glow is still a good way to go so please don't get me wrong, at this moment I don't have any of my gas engines in a plane, my kingdom for the 180 Saito OP!! Some planes just don't lend themselves to gas. Case in point, my 2M pattern plane I'm working on right now. I have the perfect gas engine for it, the old RCS 1.40 22cc high performance gasser. Problem is the engine is rear inducted and there just isn't any way to mount it into such a narrow plane without chopping things up so the carb would fit. The 1.80 would just slip right in. My little RCS 1.40 has a bunch more power then my YS 1.40 so that's saying a lot!! OK, maybe not a bunch but it does have a lot of beans!! Not all gas engines are created the same but today we are seeing a lot of good engines for a lot less money. It all boils down to the plane and it's use. I'm waiting to see some of the small gas engines in the future. Gas and electric are just two other choices we now have. I like choices!!!