|
RE: Difference between Gas and Glow engines performance wise
the bottom line is Gas is better for several reasons .... the cost of fuel is way cheaper, the reliability "engine stalls" is way superior to glow, they don't require tuning before every flight, very low maintenance, fuel tank location not critical like glow, NO MESS !!and on and on. i just got into electrics as i fly turbines and gas stuff and I'm getting rid of all my glow stuff "i don't really use it much anymore" . i won't buy a plane that i can't use at least a g-23-26. Zenoah are old school engines or maybe they were just ahead of their time. they are a very good engine. I have heard a lot of guys saying their ignition modules on the fuji's burned out along with crankcase problems . I recommend DA , Zenoah , ZDZ or 3W . in my opinion they are the best. remember when it comes to cost, you pay for nothing , you get nothing. Once you go gas , you won't go back . WB_1
|
RE: Difference between Gas and Glow engines performance wise
ORIGINAL: speedracerntrixie ORIGINAL: GaryHarris I'm glad this topic came up. I am considering moving up to large scale and gas, but would prefer not to use gasoline for two reasons. One I live in a small apartment and storing gasoline may not be an option if the manager knew. [X(] Back in the 60s & 70s I raced mini bikes and mini cycles in Southern California and it was common practice to convert our bikes to Methanol and maybe a tad of nitro. The basic rule of thumb was to triple the jet size and cut the oil in half for two strokes. I would be very interested to hear from those who have done this with the current RC engines. I don't really see the difference between storing a gallon of gasoline conpared to a couple gallons of methanol based fuel other then the smell. Both are pretty much just as flamable. As for using one or the other in a large model engine there are many advantages to gasoline. First would be the expense of gas. For a gallon of gas with penzoil 2 stroke oil added I pay about 4.50 here in sunny CA. For methanol I would have to estimate it being closer to 15.00 not to mention the gas used to drive to the speed shop to get it. Being a special trip one my be prone to buying and storing more then one gallon at a time. On a 50cc airplane run on gas I carry a 20oz tank, good for 20 mins of flight. The same engine on glow would need a 40 oz tank and not get the same 20 mins. Alcohol also attracts moisture as it evaporates. This causes glow engines to rust internally ( Bearings, crankshaft). Gasoline engines run cleaner. IMO they are also safer to operate as the ignition tends to make them behave a bit better. If you don't agree, how many of you would hand start a 150cc glow engine? As for the original poster, my vote obviously goes for gas but do yourself a favor and look at more engines that are available. The brands that you mention are some of the lowest power to weight ratio engines available. They also have magneto ignition which means they have fixed timing. That means difficult starting and less power. The new DL20 will out power your list and be much lighter. |
RE: Difference between Gas and Glow engines performance wise
I was going to move to a larger plane than I have been flying so far and was considering a Seagull Mew Gull powered by an OS 120. However after talking to some people at our local club I was considering a DLE 30 gas engine. Does anybody here know for sure if the DLE 30 will fit in the Mew Gull because it looks much bigger particularly in length with the carb sticking out the rear? Or is there a better choice of gas engine than the DLE 30?
|
RE: Difference between Gas and Glow engines performance wise
The only reason I didnt want to use nitro is that, since it is an oxidiser, I fear for rusted bearings if any is left behind in the engine.
Plain castor only to protect the engine as much as possible during its initial run-in when the piston and liner ar in the mating stage. The baffle has be baffled however, it feels rough to turn even after putting in the oil. Atleast it feels rougher than my other engines but nothing a standard servo cant take care of. With my luck with engines this year, I am worried about everything Ameyam |
RE: Difference between Gas and Glow engines performance wise
Did you purchase the engine?
I have a 1.20 ax that has been run for 2-3 gallons... They are very easy to disasemble... At the very least, pull the head bolts and take the botton (cyl cap and look inside... If you go further than that, take pictures... That way you will be able to hav reference as to how it goes back together... when you pull the cyl button, make sure the inner sleeve\cannula doesn't come with it... Unless you want to take the back of the engine off and remove the piston... Once you have done one, you have done them all (2-stroke glow)...that is... I wish OS would convert the 1.20 AX to gas.... |
RE: Difference between Gas and Glow engines performance wise
ORIGINAL: opjose Out of curiosity, how does the lack of nitro affect the engines from your perspective? Top end power will of course be off some compared to running nitro, but unless a plane is marginally powered to begin with this is not usually a concern for ordinary flying. Needle valve setting will change a bit. My experience has been that you tend to turn them in a tad compared to nitro mixes. The power/rpm will drop very quickly and noticeably if you've gone too far and it becomes too lean. i.e. the "sag" comes on much faster than with a nitro fuel. I've been experimenting with various methanol/oil mixes this year. "Standard" FAI fuel is an 80/20 mix, but I've mixed 75/25 and 72/28 for initial break-in purposes with varying proportions of Castor/Klotz. An old OS FP .35 seemed particularly docile and easy handling on a 75/25 mix with 50% of the oil package being Klotz the rest castor. Three chokes to prime, and it would start on one flip 95% of the time. That FP .35 was using the Fireball hot plug BTW. The G.34 is still on the original factory plug and has around 3 hours on it now, all running no-nitro. It too is generally a "one flipper". Some engines, generally foreign ones intended for FAI competitions, are specifically intended for no-nitro fuels and will exhibit predetonation tendencies when run with significant amount of nitro, although there was an earlier batch of Fox .74's that had higher compression ratios and would show predetonation with 15% nitro fuel. The appeal to me is Klotz/Castor/Methanol are available locally in Ft Lauderdale in 5gal cans, nitro seems harder to find unless you want to buy $2000 worth at a rip. As a general statement, it seems the larger the glow engine, the more likely it is it will function with no-nitro. |
RE: Difference between Gas and Glow engines performance wise
Our "standard" fuel right now is Klotz-100 20% with 10% nitor. That has progressed from the 80-20 plain castor mix I used last year and had a lot of issues with on a 75AX. We usually home-brew our fuel (one of the more experienced modellers does it for us less experienced or less experimented people). I have about 1 gallon sitting in a sealed container from Feb-March when flying had stopped due to non-aero reasons
kochj, havent paid for it yet. Its on "approval basis" due to "good relations" with my LHS (Guess that means I bought a lot of stuff recently;)) Ameyam |
RE: Difference between Gas and Glow engines performance wise
ORIGINAL: ameyam I am considering getting a gas engine- either Fuji or Zenoah. I wanted to know, what is the difference between a glow engine and a gas engine (other than the fuel of course). For an example, lets take Glow: 120AX or 140RX Gas:ZENOAH G26 Air Engine Fuji Imvac BT-24EI 24cc 1.5ci Gas Fuji Imvac BT-24A 23.9cc Gas I have exclusively flown glow so far. So, what is the fuel additive to gas? You know, like we add castor or synthetic lube to glow fuel... Sorry if I am a bit rough around the edges but I have no idea regarding gas engines and what fuels and additives they use, so I need a "technology primer" Ameyam Major differences between gas and glow is in the fuel metering and the activation energy. Glow engines are initiated by a catalytic reaction of the methanol to a hot platinum coil Gas engines are initated by a timed spark createed by the gap in a copper electrode. What is key is the "timed" bit. glow engines ignition timing is dependant on the heat of the platinum coil, the concentration of methanol to oxygen in the combustion chamber. Gas engines ignition timint is dependant on the timing of the spark initiated by the ignition coil. Air fuel mixture does not affect the timing of the spark but does influence the speed of combustion. GAsoline has a higher heating value than methanol fuel, so for every firing of the air fuel mix more heat is generated and hence more power can be released. in theory gasoline engines can be more poweful than glow engines. the reason they are often not is due to design. Most Glow engines are relatively higher compression ration engines. Methanol has a high Octane and hence it will not detonate uncontrollably. Gasoline typically has a lower octane value set by the specification for gasoline in various countries. Gasoline is rated according to the Research Octane Number or RON and this the resistance to knock at part load. the RONfor Methanol is around109RON(average). Cmpresion ratio is the biggest determinant in the efficiency of an engine ans since Hobby glow engines are designed for max performance they do perform well thanks to the compression ratio's being higher than Gas engines. Most gas engines sed in RC currently however have their origins in industrial equipment such as chain saws, weedwhackers, small generators etc. All these applications calls for engines operating at mostly constant speed but at high torque and they have t be durable so their specific power output per cubic inch is low. Engine designers call this under stressed. Glow engines by comparison would be close to over stressed. So currently when we compare glow engines and gas engines we are comparing an engines that is purpose built for RC against an engines that was built with power to weight ratio NOT being a concern. And therefore gasoline engine are slated for anot having sufficient power. That is changing however. Th new engines coming out of China have been placed on stringent diet and exercise programme and hence their power to weight ratios ar improving. A year ago the cut off point at which gas became too heavy was around 30cc or 1.6 class airframes. Now with an engine like the DLE20, the cut off has been moved to the 90/1.20 size plane.Perhaps if the Magnum XLS 52G actually makes an appearance it will move the cut off even further down to .46 size birds. the naysayers will disagree of course. the big change with the newer gasoline engines is the improvement in ignition timing and compression ration coupled to engine blocks that are a lot lighter. There will always be a lower limit of mass for a gasoline engine of given capacity simply due to the fact that the hrat energy in the fuel has to be absorbed by mass and that means more metal. Methanol fuel takes more heat away form the engine on its journey to oxidation an that means that the engine can be a little lighter. GASoline as a fuel will require different types of additives an oil. Mostly 2 stroke motorcycle oil or chain saw oils are suitable. Synthetics are highly recommended due to higher film strength and also for cooling since the synthetics designed for this market have lower heat of vapourisation and take more heat out the exhaust. My personal preference is for gasoline engines and I ould probably stick to the DLE engines at this point in time since they do appear to be the most competeive on power (and thrust) to weight ratio |
RE: Difference between Gas and Glow engines performance wise
So then the question would be whether to put in a 20-23cc Gas engine or 120AX in the Funtana 125. I am leaning towards the 120AX. When I showed it to the some experienced modellers, they said it was quite OK. Will show it to my mentor only on Sunday though
Ameyam |
RE: Difference between Gas and Glow engines performance wise
Yea, I would shy away from gas in a Funtana
|
RE: Difference between Gas and Glow engines performance wise
The largest engine I have so far is a FS91SII and 75AX (depending on whether you call a 2c or 4c larger). This 120 would be quite a step seeing I skipped the 91/95 sizer.
I was really out to get a gasser but it looks like that will have to wait (again seeing that I can fly but I cant drive as yet:D:D) Ameyam |
RE: Difference between Gas and Glow engines performance wise
I have a saito 125 four stroke on my funtana, I had a ax120 on it at one time but found that in slow nose up flight like knife edge circuits ALL the 2 stroke engines even with a perry pump would tend to overheat and stumble on throttle up to pull out of the low slow knife edge, not a good thing! I considered putting a gas engine in the funtana but did not like the increase in weight that the gas engine, ignition and batteries would add to it. Adding weight to the nose of the funtana would take some of the fun out of the funtana in my opinion! I bought a saito 125 and have never looked back, it is light and has never stumbled on a pull out from hover or a slow knife edge. On heavier planes, 50cc and up, the reliability of a gas engine is more important because they will not float very long when the engine dies, the funtana will float much longer on a dead stick like most smaller planes will.
|
RE: Difference between Gas and Glow engines performance wise
for the funtana i would opt for the DLE20 as the only gas option. A 4s methanol engine will provide a superior power to weight ratio.Alternatively, get the 1.6 aize funtana and fit a DLE30.The 30cc gas engine range is where it begins for aerobatic planes
|
RE: Difference between Gas and Glow engines performance wise
Gas or glow is a matter of opinion they are both good at certain things.
Glow fuel is better at powering smaller planes More powerful than gas per cc simpler in construction easier to tune ( if you know what your doing ) long life span ( I am still running a Super Tigre "X" RE that I purchased in the 70s ) Gas is better at cheaper fuel Fewer off season storage concerns ( No rusted bearings ) cleaner to operate, your plane isnt slick with oil after a flight. powering planes over 15 lbs I have flown both and far prefer the power to weight ratios of the Nitro glow engines. My planes fly better with nitro power plants. Gas just isnt there yet for me. Once the designs are brought up to todays glow fuel performance standards then maybe I would switch over to more gas engines but the gas designs we see for the most part are pretty dated. The new OS 55 gas engine is an example of what we need more of. Very nice engine indeed. For the most part I have .60 to 1.20 Nitro engines and am very happy with them. They are reliable, never dead stick and other than the fuel clean up, have for 30+ years been my engine of choice............ No reason to switch.......... 103/17 |
RE: Difference between Gas and Glow engines performance wise
ORIGINAL: ameyam So what do you think. Note that the baffle in the carb is of distinctly a different color than the rest of the engine. But the engine has obviously never been used. The glow hole is brown as I had just put in some machine oil like I mentioned in my earlier post (By the way, sorry for having to hold it with my feet while photographing. Dont have more than two hand you know:D:D:D) Ameyam |
RE: Difference between Gas and Glow engines performance wise
ORIGINAL: warbird_1 the bottom line is Gas is better for several reasons .... the cost of fuel is way cheaper, the reliability "engine stalls" is way superior to glow, they don't require tuning before every flight, very low maintenance, fuel tank location not critical like glow, NO MESS !!and on and on. i just got into electrics as i fly turbines and gas stuff and I'm getting rid of all my glow stuff "i don't really use it much anymore" . i won't buy a plane that i can't use at least a g-23-26. Zenoah are old school engines or maybe they were just ahead of their time. they are a very good engine. I have heard a lot of guys saying their ignition modules on the fuji's burned out along with crankcase problems . I recommend DA , Zenoah , ZDZ or 3W . in my opinion they are the best. remember when it comes to cost, you pay for nothing , you get nothing. Once you go gas , you won't go back . WB_1 |
RE: Difference between Gas and Glow engines performance wise
GAsoline has a higher heating value than methanol fuel, so for every firing of the air fuel mix more heat is generated and hence more power can be released. in theory gasoline engines can be more poweful than glow engines. |
RE: Difference between Gas and Glow engines performance wise
Actually methanol doesn't attract moisture. If you put a drop of water next to a drop of methanol it will not move toward the methanol. However methanol does mix with water, and the molecules in humid air will mix with the methnol when they come in contract.</p> |
| All times are GMT -8. The time now is 12:20 PM. |
Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.