2 Stroke vs. 4 Stroke
 

What are the pro's and con's of 2 and 4 stroke engines?

Andrew

RE: 2 Stroke vs. 4 Stroke
 

Two strokes are usually cheaper to buy than four strokes. They have less moving parts and are generally considered 'easier' for a person new to the hobby to operate.

Some, not all, two strokes run well at idle and full throttle but not so well at half throttle. My Thunder Tiger 61 never ran well at half throttle but my ASP 61 does.

All of my four strokes seem to run well at half throttle and all other settings.

My .61 two stroke burns more fuel in a 10 minute flight than my .91 four stroke. Many people believe the .61 two stroke and .91 four stroke are fairly equivalent in performance.

A totally subjective point; I think four strokes sound better than two strokes.

RE: 2 Stroke vs. 4 Stroke
 

This isn't really an answer to the original question, but I wish I got into four strokes sooner than I did.

I guess the biggest advantage I see is the immediate throttle response, due to the higher torque of the 4 stroke. When you ask for power, you get it immediately instead of waiting for RPM to increase. There is less top-end power, but you can use a prop with a higher pitch so you don't need to go there.

The sound is great, it's really neat having a little engine with valves and stuff (i.e. the neat factor). My four stroke seems to make less of a mess than my 2 strokes, and seems to be quieter overall.

RE: 2 Stroke vs. 4 Stroke
 

4-strokes:
Sound more scale-like
More fuel efficient
More torque - spin larger props

2-strokes:
Higher power:weight ratio
Higher rpms for more speed
Cheaper, simpler.<br type="_moz"/>

RE: 2 Stroke vs. 4 Stroke
 

I'm with Joe, Ithink it's more of a cool factor!!!http://www.rcuniverse.com/forum/js/f...ular_smile.gif
Ihave heard this debated before at the field, we all know how that goes, the thinking was that the four strokes were developed because of the noise factor?? You be the judge.
They do throw a bigger prop, they do use less fuel, they do produce more torque and they do sound cooler.
Other then that Ihaven't noticed much difference in flight. There may be less engine snot on your plane at the end of the day?? Now that Ihave seen it mentioned that could be right? Maybe not?? Ihave never seen a Saito that didn't sling so much snot the plane wasn't dripping when it landed, Ihave one YS that is really snotty too but that could be where I have my muffle pipes exit??
Idon't know, Ithink it really could just be the cool factor?http://www.rcuniverse.com/forum/js/f...y/msn/cool.gif
What ever it is Ijust really like them and don't have any plans about changing any time soon.http://www.rcuniverse.com/forum/js/f.../msn/49_49.gif

RE: 2 Stroke vs. 4 Stroke
 

Saitos: definitely messy.

YS: A little less messy than the Saitos and the most powerful of the bunch.

OS: Very clean, not quite as clean as a gasoline engine but not bad. Very little oil on the plane after a flight. They run very good too. Probably second only to YS in my opinion.

2 strokes: Nothing wrong with them at all. Definitely cost-effective. Just gotten to where I can't stand listening to them. Inever say never though. I may have one again for something one of these days.

All just my opinion of course, your experience/perception may vary.

Bottom line is fly what you like and have fun.

RE: 2 Stroke vs. 4 Stroke
 

Got my hands on 2 different Magnum 4 strokes and neither was worth owning.

RE: 2 Stroke vs. 4 Stroke
 

I'm in shock!!!!!!!!http://www.rcuniverse.com/forum/js/f...ey/msn/lol.gifJeff, say it isn't true!!!!
As to the two strokes Iwent over to the SK engines and have been very pleased with performance, price and sound. Irun the SK .91, they take a big prop, anything less then a 15 inch and it will run lean, low RPM engines with stump pulling torque and very quiet!! For 100 bucks I like them a bunch better then the OS these days but I try not to fly real fast planes so the low RPM is perfect for me.
Hot rodders need not buy!http://www.rcuniverse.com/forum/js/f...wink_smile.gif

RE: 2 Stroke vs. 4 Stroke
 

I managed to get my Magnum 2 stokes to run well,,,,,,,,,,,,,with a Thunder Tiger carb. http://www.rcuniverse.com/forum/js/f...ssed_smile.gif

RE: 2 Stroke vs. 4 Stroke
 

I think that regarding the 'not cool' sound of a2 stroke.... a pitts muffler installed ina 2 strole can change the noise pretty nice... do not you think guys????

RE: 2 Stroke vs. 4 Stroke
 

It is entirely subjective as to the sound of the engine being pleasing. I happen to like the sound of a screaming 2 stroke even if it doens't sound like a full size plane. To me it just sounds Fast!

RE: 2 Stroke vs. 4 Stroke
 

i love the sound of a four stroke on a slow fly by, nothing will beat it, their torque, "coolness" factor, and idle/midrange sound

however when you just WOT a two stroke in the air and it starts screaming, man it sounds great.

RE: 2 Stroke vs. 4 Stroke
 

Chuck, that's funny - it's been a week and I totally agree! I fired up the 120 two stroke today and immediately was disgusted by the sound (and of every other 2 stroke I heard today. Thankfully there were some 4 strokes and a gasser).

This is totally subjective. Both engines will fly a plane just fine.

RE: 2 Stroke vs. 4 Stroke
 

Quiet is good. Noise does not equate to power.

Many clubs have restrictions on noise, rightfully so.. they could lose their flying privilieges by the locals.

Pattern events alsomonitor noise limits as do other sanctioned events.

RE: 2 Stroke vs. 4 Stroke
 

Our club is one that has noise restrictions.The difference to members is you can fly a larger engine in a four stroke without a special muffler than a 2 stroke. A 120 two stroke can make a lot of noise with a stock muffler and is usually too loud to meet noise requirements, especially with certain props.

RE: 2 Stroke vs. 4 Stroke
 

I think you hit it on the spot. I would also add that 4 strokes are more complicated and expensive. Also, they are heavier. I got rid of all dirty and oily nitros, and only fly electric or gas.

The only important thing is to remember is: The best powerplant is the one YOUlike:-)

Good luck

Gerry

RE: 2 Stroke vs. 4 Stroke
 

2 strokes are cheaper and have more top end power.

4-stroke. once broken in run better, idle better, use alot less fuel, have loads more tourqe, low end. sounds cooler and are quieter.

RE: 2 Stroke vs. 4 Stroke
 

One more difference worth mentioning. A four-stroke prop hitting your hand hurts a lot more that a two-stroke prop on a comparable engine. It's the torque. Best 4-stroke advice I ever got was never touch the prop with your hand.

RE: 2 Stroke vs. 4 Stroke
 

I wouldn't go sticking my hand in a prop on a 2-stroke or an electric either.http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif High speed spinning knife blades and human flesh &amp; bone just aren't a good combination.

RE: 2 Stroke vs. 4 Stroke
 

No kidding, a chopOmatic is just something I try to avoid, I don't care what is powering it!!!
A Pitts muffler sure does change the sound of a two stroke, Ihave a couple of Bison mufflers that make my SKs sound different, mater of fact they are even quieter then my four strokes.
As to the type of engines I use?? As stated, what ever will fly my planes.
My gassers are a bit on the loud side but the mufflers are nothing but square cans with pipes sticking out to direct the exhaust away from the plane. Ihave one fellow I fly with that spent big money on cans for his big twin and it was the loudest plane I have been around, he changed the prop and the same plane is really pretty quiet now. Props make a big difference in the sound!
Ijust really like my four strokes and other then one of them they are pumpers so plane/tank set up is really easy, they don't care where you put the fuel tank.
And that cool factor!!!!http://www.rcuniverse.com/forum/js/f...wink_smile.gifhttp://www.rcuniverse.com/forum/js/f...eeth_smile.gif

RE: 2 Stroke vs. 4 Stroke
 

After one more day with my big 2-stroke I am ready to start selling off all my two strokes and replace with four strokes. I got spoiled, fast!! I have no problem giving up top end power for more torque and immediate throttle response. The amount of time I had to wait today to reach max power with my 120AX is stupid[:'(]. It's 2009, and when I want power, I want it NOW!!

And did anyone mention simply how much cooler four strokes are?![8D]

RE: 2 Stroke vs. 4 Stroke
 

Me thinks Joe has a bad case of the YS spoiled!!!!http://www.rcuniverse.com/forum/js/f...ades_smile.gif

RE: 2 Stroke vs. 4 Stroke
 

I just started flying my first 4-stroke - a Saito .62 on an Ultra Stick .40, otherwise I would have used a .46 2-stroke. On the US40, the engine is sidemounted. That puts the idle needle facing the bottom of the aircraft (but it would be the same on a 2-stroke). Makes setting the idle a bit more complicated but once it's properly tuned, you won't have to change it by much.

I'll dispute the 4-strokes are heavier than an equivalent 2-stroke. The stock muffler on a 2-stroke is really heavy. I also have a Sig 4*60 which the previous owner originally had an OS .61 FX with a bit of noseweight. Ifitted a Saito 1.00 and will have to add MORE noseweight.

Cost of the 4-stroke is over twice what a 2-stroke costs. They slobber up the airplane less than a 2-stroke, sound better, run well and use a LOT less fuel. I'm really liking Saito-powered Ultra Stick.

RE: 2 Stroke vs. 4 Stroke
 

It's $240 for a two stroke 120AX without muffler vs $350 for a four stroke FZ110-S. That's 50% more money for a 10% smaller displacement engine.

BUT, the $110 may be worth the better running, lower fuel consumption, less noise, better sound, higher torque and the lower mess factor.

For anyone having both a 120S-E Surpass (864g w/o muffler, max 11000rpm) and a FZ110-S (730g, 13700 max rpm) , how do they compare for power, and consumption? Close?

RE: 2 Stroke vs. 4 Stroke
 

I have the OS 1.20 FS pumper and the YS 1.10 and the YS is just way more power and lighter. As for the 1.20AX and the YS 1.10 go ahead and ask ga what he thinks, he is just starting to get into his YS. I think it took him maybe one flight to make up his mind. Idon't see him ever looking back again.
Ithink he stated he will make you a deal on a good almost new 1.20AX!!!
I'm not real sure about that?? What say you Joe??http://www.rcuniverse.com/forum/js/f.../red_smile.gif

RE: 2 Stroke vs. 4 Stroke
 

Get the YS dialed in and hammer the throttle one time and you'll quickly forget about fuel consumption and other stuff. The OS 1.20 is good but the YS is in another category alltogether.

RE: 2 Stroke vs. 4 Stroke
 

<span style="font-family: Tahoma"><span style="font-size: medium"><span style="color: #000080">A little history of the YS 4s engines.
Did you know that Surer Tigre developed the engine a very long time ago!
Their concept of crankcase supercharging was the first in model avaition!
The modeling comunity thought the engine wasn't worth the effort to try it!
ST's boss sold the tooling and rights toa japaneese firm.
YS spent much time and money pushing the 4s concept.
Pattern flyers were the first to use it fully, when cu in limitations were imposed.

I'm afraid that the time frame escapes me but, it happened over 25 years ago. I can stand to be corrected!
OS tried to SC one of their 1.20s. Used a Roots type blower, engine driven, to match YS. Never did!
But OS 120 supercharged engines ARE a thing of beauty. They never achieved the HP that a YS did, and were more prone to wear.
I use YS engines and, yes, they have a sound that can't be beat and they deliver the torque!

I also like the sound of big hairy radial engines...ie PW4360 ! PW2800 ! CW3350 and the list goes on.....http://www.rcuniverse.com/forum/js/f...wink_smile.gif

POP POP POP goes the 2 stroke..... GRRRRR goes my YS !!
http://www.rcuniverse.com/forum/js/f...wink_smile.gif
I love a good discussion!
M Zorger
AMA129570
</span></span></span>

RE: 2 Stroke vs. 4 Stroke
 

Nope, didn't know that but my advanced flight instructor was one of the first guys in this country to get the YS for pattern flying. He was working at a big hobby shop at the time. He got me into the YS by allowing me to fly his CG Extra with the YS 1.20NC then my CG Extra with the OS 1.20, my plane was a bit lighter but it was apples and oranges. With the price jump by Saito and OS I can't understand anyone buying them when they can get a YS.
Does it sound like I'm sold on them?? Plus I can buy any and all parts for a YS without having to send them in for service. Another big plus.

RE: 2 Stroke vs. 4 Stroke
 

Here's a little video I put together of a few planes, the first being a YS FZ110-S in a QuiQue 72"Yak,
that demonstrates the sweet sound and power of this engine. Click HD on lower right after clicking below link.

http://www.youtube.com/watch?v=itCeAX0HRlU

RE: 2 Stroke vs. 4 Stroke
 

Good video. What kind of AMA waver do you need for that space shuttle in the beginning?http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif

RE: 2 Stroke vs. 4 Stroke
 

Thanks!The waiver is pending:) By the way, looking at your hangar - very impressive!You seem to be mainly an OS guy though, didn't see any YS engines.

RE: 2 Stroke vs. 4 Stroke
 

Ihave a couple, .63 and 1.10. Finding that Ilike the gasoline engines even more though. Slowly migrating that way.

RE: 2 Stroke vs. 4 Stroke
 

There's no dispute that YS 4-strokes produce best-in-class power for any given engine size, but to get that power you have to use high nitro fuel (20% ormore)andthe costcan start to add up.

I'm kinda like Gray Beard. I like the 2-strokes that can turn large props. My personal preference is for Webra's. Nitro in Europe is expensive so engines made there typically peform really well on very little nitro.

I have a Webra .91 2-strokethat runs extremely welland effortlessly turns a 15x8 prop in the mid 9's. Remember, this is on FAI fuel or 5% nitro so my fuel costs are considerably cheaper. The OS equivelent can't even reach those rpms on 15% fuel.

Can any tell me what a YS 1.10 turns15x8, 16x6 and16x6 props at?

</p>

RE: 2 Stroke vs. 4 Stroke
 

My YS was turning a 16x6 at just over 10,000 RPM, richened down to about 9800. Now it's turning a 15x10 at 8800, which is about the same RPM I got with a 16x8.

RE: 2 Stroke vs. 4 Stroke
 

More comparison between nitro, gassers, 2 stroke and 4 stroke please
 

I’m late to this thread but I have gone through it and still confused.
I'm a beginner and haven’t done my A cert yet but it was the sound of combustion aeroplane that triggered that bug in me.
If I ask something stupid, please ignore it as I’m still a beginner and I’m aware I’m asking a lot of questions.

I want to know the comparison between 2 stroke nitro, 4 stroke nitro, 2 stroke gasser and 4 stroke gasser.

The information that I would like is

• what type of fuel or fuel mix
• the ‘cool or the sound’ factor (after all this is the original cause of all ills:D)
• mess that it creates
• Maintainence
• original purchase cost is less of an issue but maintenance effort and cost is
• and which brand is better

And if someone can also do a comparison on these lines between

• 2 stroke nitro with 4 stroke nitro
• 2 stroke nitro And 2 stroke gasser
• 2 stroke nitro and 4 stroke gasser
• 4 stroke nitro and 2 stroke gasser
• 4 stroke nitro and 4 stroke gasser
• 2 stroke gasser and 4 stroke gasser (I want this the most)

Many thanks in advance

For the T-Two Stroke fanatics: The F-F-F-Four Cycle Page

For the F-F-F-Four Stroke fanatics: The T-Two Cycle Page

Sounds like an inept tuner to me if one can't tune a 2 stroke or a 4 stroke to idle, reading the foolishness and false information in those links. I'd avoid any posts from incompetent users that blame the engine. They likely also destroy their batteries as well unable to handle the electric component of the hobby also. The glow engine has been around 80 years, give or take? It wouldn't have passed down generations if everyone had the same conclusions of those not capable of learning but create misleading websites linked above.
​​

• what type of fuel or fuel mix

Most don't pay the hazmat fee and order online, or make home brew when they're a novice. Most 2 strokes you find left for sale today from distributors that have survived this long as going to provide you user friendly engines that work with the available fuel on the market. Any hobby shop where you pick up your fuel is going to only supply a limited number of choices these days, so it's simple. Generally speaking, 2 strokes often suggest 18% oil content. They will run on 0%, 5%, 10%, 15%, and 20% nitromethane content if not more. 10%-15% is the most common that you see today. 4 strokes require a little less oil content, and a little more nitromethane to perform at their peak. But are just as forgiving. I fly at sea level, so these statements are under these conditions. I remember flying in Santa Fe as a kid and with the high altitude, nothing ran right, so a lot of adjustments needed to be made. Power was compromised regardless.

• the ‘cool or the sound’ factor (after all this is the original cause of all illshttps://www.rcuniverse.com/forum/ima...es/biggrin.gif)

You'll find sound to be a personal preference. I suggest you search the marketplace and other forums for a used engine, saving you a lot of money from Tower Hobbies current prices for engines and you don't have to break it in. Most like the 4 stroke sound over a 2 stroke sound especially in scale airplane applications. https://www.modelairplanenews.com/fe...sitor_pref_pop

• mess that it creates

I don't even worry about it. I bring my cleaner and towels, and it's just part of the program when I'm done flying and packing up. When I clean my toilet, trash cans, or come home from a day of fishing, I don't worry about the mess that creates either. That being said, fuel residue can be reduced if not eliminated. There is only a mess when the output of the exhaust isn't deflected away from the model you're flying. 4 strokes permit you to extend the deflector farther from the model without effecting performance or tuning, and I mean several inches. 2 strokes are far more sensitive to exhaust length and extension but a short deflector or side mounting of the engine helps considerably in reducing post flight clean up. I had an Ultra Sport with a OS 61 using a header/pipe for an exhaust and never had to clean the plane once. If you are asking about mess, this likely isn't for you. Glow/gas, you accept it as part of the activity.

• Maintenance

When you're done flying for the day, pour some ATF or Marvel Mystery oil down the carb on a 2 stroke engine to lubricate the bearings during storage or between weekend flying. 4 strokes have a nipple typically found under the case that you have to attach a fuel line to and inject the oil into that area to lubricate those bearings, often overlooked. Some add oil down the carb on a 4 stroke and it never gets to the bearings. Regardless of fuel you use, after run oil after a flying day is necessary to preserve the bearing life. One can upgrade their engine to ceramic bearings and avoid internal rust, but there are other components that can lock up over extended periods of time. I buy my bearings from Boca Bearings in FL. That's the only maintenance I've had to worry about. For extended storage, the fuel tank will have fuel residue that has to be cleaned out before you go flying again. After a couple of seasons, I'd replace the fuel lines. If you improperly tune your engine or select the wrong heat range, you'll cause glow plug failure, but otherwise I get many years of use out of them.

• original purchase cost is less of an issue but maintenance effort and cost is

Is this a statement or question? Let's take this space to talk about your glow fuel vs. gasoline comparison. It's not really correct to call it nitro. That term came from the car crowd, not the airplane crowd I believe? Glow fuel is a mixture of methanol, nitromethane, and oil. Nitromethane is only 10-15% content, and even the oil is typically 18% for 2 stroke engine fuel, and they are capable of running without nitromethane in the fuel, so what would you call it then? It produces more power than the gasoline counterpart, displacement for displacement. So the gas engine is going to be heavier, turn fewer RPM, and is a rather new technology they've been working on to improve tuning to match that of the glow fuel engines. Some companies do it better than others. These are also expensive engines up front, and pay you back in fuel savings over time. But I'm not a fan of storing gas, mixing my own fuel, paying the up front cost to see if I got a good engine or not, don't want the additional weight, and I still get glow fuel for $12/gallon in Orlando FL (Graves RC) which isn't that much of a drive for me. I'm familiar with glow engines (45 years) and have dozens of them laying around waiting to go on an airplane. No reason to buy anything else. That's just my circumstances and taste. More power to the modeler that abandons the glow and goes gas. It's not irritating to me to wipe down a plane with 409 cleaner and some paper towels if necessary, and to others, they hate it. I guess the fact that I've changed my sons diapers, clean my own house, do my own laundry, all things considered, I find castor residue far less offensive to me?

• and which brand is better

Again very subjective and no right answer here. If this were a car topic, is Ford, Dodge, Chevy, or Toyota better? If you're pulling 10,000 lb trailers, which is better then? Some like Saito for its characteristics, some like OS, and there are others. Today, not many glow powered engines have survived the decline of their popularity as electric dominated the hobby. What's left is "better" than what failed and left the marketplace. Most like OS 2 strokes for the tuning ease and they forgive poor tuners. Unfortunately the nickel liner process vs. a true ABC engine, they don't take abuse well or last nearly as long, meaning 5 years vs. decades. 4 strokes you don't have to worry. All manufacturers make a long lasting 4 stroke if properly maintained and you use a tach, tune it in the proper RPM range, prop (load) it correctly, etc.
If you decide to get into gas or glow, I watch others who pay a premium for gas and do just fine, but I've yet to see one perform as well as glow or be as lightweight. For the amount of flying you do a month, would determine if the fuel savings is right for you to make gas truly worthwhile an investment, and go through the learning curve on brands, tuning, etc. which you would do anyway with glow to some degree. But, I suggest you shop from FB, CL, local club, or RCG, find a local sale with the engine, servos, and plane ready to go as a used package that someone no longer wants, than piece meal each or buy new. Doing that, you'll always find glow and very few gas powered plane packages, but you'll get in the air on a budget, especially if this is just an experiment that you may not continue, at least you got in the air for a lot less money and can always get out of it for what you paid.

Test
 

Test

Hi!
All two and four stroke engines sold the in the last fifty years or so are all good!
The start easy, throttle perfect! and run perfect...if you set them correctly!