Other than cost of fuel, what are the advantages of using a gas engine compared to a nitro in my large scale, aerobatic/3D plane?

top of my list is reliability. the percentage of deadsticks has dropped in my planes that have a gas engine.

I agree with reliability being #1. Once you get the needles set correctly on a gasser you probably won't have to touch them for the next few years. Spark plugs last a long long time. You can use half the fuel tank size for the same flying time. Gassers are less likely to backfire and hurt you. You can usually get a lower reliable idle. When treated right gassers will last a long time. Gassers will need more cooling air and baffles because the fuel doesn't contribute to engine cooling.

The size of your aircraft is a big factor. Its difficult to get any of the 25cc gas engines to match the power and weight of common and cheap to buy glow engines. The performance difference disappears with the lightweight 40cc, and most all of the 50cc and larger engines with electronic ignitions. As far as reliability, it depends a lot on the individual. Its usually easier to get 100% reliability form a chainsaw than from a glow engine, right up till you get rf interference and lose a plane. That may buy years worth of glow fuel.

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Your glow engine's muffler can loosen and do the same thing (glitch your receiver to destruction) to your glow model.

With the latest offerings from China, the 26cc gasoline size is now coming into its own. The old 40cc lower limit is being shoved downward by progress.

Here are the advantages and disadvantages of both engines IMO

Advantages with the gas engines are
Lower fuel cost
Walbro type fuel pump/carburetor feeds your engine
Almost no need to cleaning

Advantages with glow engines are
More power
Lower weight
Usually cheaper to buy
Smells good when I fly and I can store them in my basement without my wife killing me
The engines looks better and are smaller
No risk for RF interference caused by the engine

You guys are kidding about the RF interference right? Seriously, if you don't do anything dumb and follow the simple rules of engine and servo installation you will never get interference. If you range check your airplane like you are supposed to do you would catch it before you crashed an airplane. An airplane that does not get RF interference won't just suddenly get it years later unless you do zero maintenance on your airplane and have things falling off of it.

I have been flying gas engines for 20 years and have never encountered RF interference from my ignition. IMHO RF interference does not belong on the list as a usual problem or risk.

Also not on the list, (mostly tongue-in-cheek)

If you run gas...
Your radio face-plate won't delaminate from having glow fuel on your hands.
You won't smell like you went flying from standing behind a glow motor during start up.
You won't die slipping and falling in a glow fuel spill.
You will always have fuel for the weed-eater to do yard work.
Your airplanes get old from 2500 flights not from fuel soak.
You get to build an addition on your house to hold your giant airplanes, thus increasing your property value.
You get to own an additional (giant sized) vehicle just to transport your giant airplanes. The neighbors think your loaded.

here is a test on what is better for me....

fly a gas plane for 15 minutes

then fly a glow plane for 15 minutes

then go pick each plane up... now look at your hands... you tell me which one wins!

I agree. I currently keep 7 gassers ready to fly at all times. I don't even own a PCM receiver. I do all of my flying with PPM/FM equipment and never have glitches.

Flyer95 said:
Advantages with glow engines are
More power
Lower weight
Usually cheaper to buy
Smells good when I fly and I can store them in my basement without my wife killing me
The engines looks better and are smaller
No risk for RF interference caused by the engine

More power, you are probably correct if you are talking about 10 - 20 cc engines. If alky engines are more powerful then why don't we see them in 1/5th scale warbirds or 100" ws 3D airplanes? They also gobble great amounts of $15/gal fuel.

Lower weight, have you looked at the weight of BME 110. You are probably right if you are looking at little 10 - 30 cc engines.

Cheaper, have you priced a Super Tiger 3000 lately?

Smells good, I can't smell my plane when I fly. Don't you just love the smell of gasoline in the morning?

The engines looks better and are smaller, have you ever looked at a BME 110? It's a tiny looking engine producing over 10 hp. Looks is in the eye of the beholder.

No risk for RF interference caused by the engine, see above.

It's all from your perspective. To each his own.

Show me a glow engine that will power a 30-40 lbs 3D ship.

True, I look at the glow to gas transition as an engine progession from smaller to larger planes. There's very little overlap for me. I'd say on the 120 size aircraft you can use the big bore glows like the Saito 220, YS 160DZ, Moki 2.10 etc. Or you can use a gas engine on the same planes. Then you can do a comparison. But as mentioned, once you are 80 inch and above it's all gas for me. As far as a "throw it your trunk and go" plane, it's a small glow engine (or an electric foamy).

I have electric, glow, and gas engines for all different sized aircraft. I'm not always in the mood for dealing with a big plane when I go fly.

Yup... I just got a MOJO so I can skip the trailer and just go toss something in the air. I also have a 3DFOamy SuperExtra electric for a nice large heavier electric that can handle some wind... both are hoot!

For real fun though... 35%!

OK! Not sure if this will do it but I thinkit will come close.

http://www.mecoa.com/kavan/index.htm

Also available in gas.

Purdy, but not even close. A 20x10 prop and 5.7 lbs!!! A DA-100 is the same weight and turns a 28x10... need at least this for a 30lbs airplane. The Kavan would barely taxi it.

WOW $6,500 for a glow engine. Probably about the same power as a Zenoah G-38.

Did you see the price for that engine

Karol

Hello Guys,
I have both glow and gas engines so I dont prefer one instead of the other.
Almost every guy that I know run gas or have run gas engines, including my self, have had rf interference atleast one time caused by the ignition system. The electronic ignitions are usually much better. I liked my Brison 5.8 and CH ignition very much[sm=thumbup.gif].

I agree with the you big bird. I am only talking about glow engines smaller than 30-35cc as there is no reason running glow engines any bigger than that unless you are into giant scale pylonracing.

I believe you are right. As I recall Ralph Cunningham (RCIGN1) runs a 289 cc Herbrandson sp. on alcohol in a racing plane.