2 or 4 Stroke??
 

I currently have a Tower .61 2 stroke for my Tower 60 Trainer and will use that for quite awhile. For my second plane I like the Contender 60 (TopFlight kit) and would like to put a 4 stroke in it. Other than fuel economy, torque and personal preference, are their any other reasons to use one type of engine over the other?

2 or 4 Stroke??
 

Noise is the only other factor I know of.

2 or 4 Stroke??
 

extra weight to balance the plane???Did I win anything or was that just a plain ole weekend question?
Have fun John

2 or 4 Stroke??
 

alstack
2 strokes are in general easy to operate, i really like to train beginers with .60 trainers like the one you have, and once you are ready for the next level, it will help you to use your thrusty engine from the trainer, it will be well broken-in and you will understand it 100 %, my sugestion is to keep it until you feel comfortable with the contender and then if you want explore the 4-s territory change to it.

2 or 4 Stroke??
 

How about COST? *%#@* :(

2 or 4 Stroke??
 

There's nothing wrong or difficult about a 4-stroke. If you want one, go for it. Most of them are fine engines.

2 or 4 Stroke??
 

4-Strokes run MUCH cleaner too! They generally leave about one tenth the oily residue on you plane than a 2-stroke does. I use 4-strokes almost exclusively except in my real "hotrod" airplanes. I'm always amazed at the mess after flying one of my 2-strokes!

2 or 4 Stroke??
 

Thanks for the info. This is all new and interesting, I value the varied oponions.
Thanks,
Al

2 or 4 Stroke??
 

G'Day Alstack,

Please keep in mind that the Contender is a relatively heavy plane. I have an OS .46 FX in mine but I needed an 11x7 prop to give it the pull I needed. A .60 sized engine would be great (though you will have to carve out lots more cowl

A 2-stroke will give you more speed but the 4 stroke will give you more pull. Depends on the kind of flying you want to do as well. Basically the 4 stroke will swing a bigger prop.

If you do a search on "Contender" you'll find a thread that talks about various mods that will benefit the operation of the plane.

Good luck

Nuker

2 or 4 Stroke??
 

In my personal opinion, during the learning stages it is very important to be relaxed and calm (as much as possible, of course),
it is during this learning curve when your airplane/s will be facing accidents and such, guess what hits first when you crash (most of the time, anyway!), having and engine that costs more than twice the price of another (while acheiving the same thing) can be cause for the "shakes" to most people, specially those that start on this hobby later in life, for the younger generation, price is more the issue. A two stroker can take a lot of hits and still be operable, four strokers are more prone to damage and are much more expensive to repair. I believe a two stroker is easier to learn the basics of model engine operation, while learning, one of the most annoying things is to have engine problems, so make sure you buy a good, well known, easy to care for engine, two stroke that is, when past the learning stages, by all means go and get a four stroker, they sound so gooooood!!

stick with 2-strokes
 

I've had both 2 and 4-stroke engines.

Won't buy another 4-stroke-----ever.

4-strokes DO NOT swing a bigger prop!! Up here in Denver we run an OS91FX with a 14-6 prop. We run a Saito 91 with a 14-6. Same prop. Run a ST3000 (30cc-1.8cu.in.) with an 18-6 or an 18-8. Same prop on a Saito 180. Run an OS61FX with a 12-6 and a Saito 72 with a 12-6; same prop

I have never understood why guys say that 4-strokes swing bigger props. They don't. And noone is gonna convince me of that until I see it for myself.

Yes, you could run a 20-8 or a 20-6 on a Saito 180. And I can also run the same prop on my ST3000. Big deal. Both engines will turn less RPM with the bigger prop. And RPM is power. I don't care what anybody says; these little airplane engines thrive on RPM's. You lug them down and you ain't gonna get any power out of them. Period.

So stick with the 2-stroke and keep it wound up tight. (high RPM's).l

2-strokes are LIGHTER, CHEAPER, and they have a better POWER to WEIGHT ratio.

You ain't gonna get a 4-stroke that weighs 3 pounds to put out as much power as a 2-stroke that also weighs 3 pounds. Period. Power to weight ratio.

2-strokes are simpler too. If it ain't running right, then you check the glow plug(works about 95% of the time) or check the fuel mixture. Very simple.

If your 4-stroke ain't running right; then you might as well pack it up and head for the house. They are not very user friendly when it comes to field tuning. Could be your valves or your plug or your fuel, or a host of other things. Too much trouble to mess with.

Like I said. Stick with 2-strokes and keep 'em wound up tight. Thats where your gonna get the most power for any given weight.

Okay, I'm off the soapbox now. Sorry.

2 or 4 Stroke??
 

Hi RcPilet,

Our comments, as always here, are prefaced with IMO (not everyone will include the H; notice that I didn't; DOH) :) ). (not looking for a flame war here, this isn't directed at anyone)

I would suggest conferring with experts in the field (e.g. Clarence from RCM). 4-strokes are documented, even by the 2 stroke manufacturers, as having more torque (thereby allowing a bigger prop to spin if you wish), lower fuel consumption and burn cleaner but, to your comments, harder to tune and more expensive, than their 2-stroke counterpart. For sound, nothing beats the 4-stroke either :D

No one is saying that 2 strokes are bad; there are just differences in what the engines provide. Alstack, who started this thread, seems to be mostly right on the mark for what he is looking for. In all honestly this discussion is probably best left to the Engines forum where it is hashed out weekly :confused: .

As for Alstack, he can get the engine he wants to get for his Contender and enjoy it. That's really what it's all about.

Nuker

2 or 4 Stroke??
 

Nucer, you are so correct. Either make of engine has its good and bad points. I particularly like the fact that you can get good power out of the four strokes at less RPM (much quieter) and they allow much neater aerobatics at lower speeds. Now some people just like high speed and noise so they will like two strokes better; nothing wrong with that, let them have their fun also. I also like the fact that the four strokes run twice as long on the same abount of fuel while still putting out as much power. The exhaust on the 4 stroke is much hotter though and this can cause problems in some cases. Also, for equivalent power, the two stroke is much less expensive.

2 or 4 Stroke??
 

Happy Coast Guard Day, Al.

Marion, WI? Are you involved with the Ida Lewis class construction @ Marinette?

My father was USCG for 25+ years...

Oh, and Friends dont let Friends fly 2-strokes *but I fly 2 myself... guess I don't have enough friends:)*

2 or 4 Stroke??
 

"I also like the fact that the four strokes run twice as long on the same abount of fuel while still putting out as much power."

ain't so. Who told you that?

I like 4-strokers. I also like 2-strokers. :)

2 or 4 Stroke??
 

BGI, who told me? noone, learned from 20+ years of using both 2 and 4 strokes. Rod

2 or 4 Stroke??
 

Rodney, really? In my experience, the OS 160 FX uses less fuel than the Saito 180. My TT .91 FS sucks down the fuel about the same as my K&B .61. Maybe it's true for the smaller engines? Hmmm...

thanks

2 or 4 Stroke??
 

RCPilet is correct! The same sized 2 stroke will have more power and usually more torque than the same sized 4 stroke. Only old low power 4 strokes used significantly less fuel. Newer engines may save some fuel, but not much and a few engines may not save any fuel at all. Problem is many people keep comparing larger 4 strokes to smaller 2 strokes. This came out of an old AMA pattern rule which allowed 4 strokes to have 1.5 more displacement than the maximum sized 2 stroke. Guess what the pattern boys switched to 4 strokes because they produced marginly more power than a 2 stroke 2/3's the size. An exception is the YS 4 stroke which produces about the same power (more or less) as the 2 stroke. Also, unless you find a good place to vent the crankcase you will get about the same amount of oil on the plane with a 4-stroke as a 2-stroke.

That said I like both, with an edge to the 2-stroke cause of the lower maintenance.

2 or 4 Stroke??
 

Interesting. I recently replaced an OS 46FX in one plane with a Magnum 52 4 stroke. On the same size tank (8oz) my flight times increased from 10-12 min to 15+ on the 4 stroke.

2 or 4 Stroke??
 

I use both 2 and 4 strokes. As a few people have mentioned, neither is better, they are just different. You can use either in ANY plane. However, IMO each has advantages over the other. I use 2's for high-speed planes, and 4's for military and aerobatics. I don't care what ANYBODY says, 4's burn MUCH less fuel than 2's they are 10 times cleaner, and OH THAT SWEET SOUND!!!

Let's face it, wouldn't you cringe to see a Harley-Davidson HOG cruising down the street with a 2-stroke Kawasaki engine screeming along? (Rrrrriiiing-ding-ding-ding-ding)

2 or 4 Stroke??
 

I find that a Saito 72 installed in the same place as an older (11 years) .65 magnum sucks about the same amount of gas. Saito is turning about an inch more prop dia. wise with same pitch.

Speed's pretty much the same.

2 or 4 Stroke??
 

a two Stroke will have more speed because of higher RPM's the four stroke will idle lower and turn a steeper pitch prop

2 or 4 Stroke??
 

Just remember that a 2 stroke is lighter than a 4 stroke of the same power level. If you like the sound go with the 4 stroke, if you want the best power to weight get the 2 stroke!

2 or 4 Stroke??
 

A Saito .72 is pretty comparable to a .46 in weight, if not a little lighter.

2 or 4 Stroke??
 

IMHO all the participants aren't quite discussing the same points.

I'm more than willing to give in on the point that some 4-strokes of the "same power level" burn less fuel their 2-stroke counterparts even if my limited experience with 4 specific engines don't support this (saito 180 vs os 1.60 and .61 K&B vs TT .91 FS).

But we have some people comparing .91 two-strokes to .91 four strokes while at the same time others are comparing .61 2-strokes to .92 four-strokes (and similar).

Let's try to agree on what we're debating. :)

2 or 4 Stroke??
 

Well.....2 stroke equals firing everytime the piston reaches TDC.
4 stroke (as the name implies) fires every OTHER time the piston reaches TDC. Hence, better fuel economy.

2 or 4 Stroke??
 

The reason for that is that a 6o 2-stroke is comparable to a 90 4-stroke. If you look at an airplanes specs, it will usually say something like:

Engine size:
60 - 90 (2-stroke)
90 - 120 (4-stroke)

No doubt about it, 2-strokes are smaller with more power-to-weight ratio than 4's.

4's are just so sweet. But for a beginner, I'd stick with a 2.

2 or 4 Stroke??
 

A .60 two stroke is not comparable to a .90 four stroke! The four stroke is more powerfull! Years ago they allowed the pattern guys to use 15cc sized 4 strokes while the limit for two strokes was 10 cc. Well at the time maybe they were comparable but with the next generation of 4 strokes (which came out immediatly after this rulling) the pattern guys switched to the 4-strokes. A typical sport .60 is probably more compareable to a .80 4-stroke.

2 or 4 Stroke??
 

This is quite correct,

if money is not a problem you may be better off
buying a 91 4 stroke instead of a 61 2 stroke since they pretty much very similar in size nowadays, Saito is even lighter.

With the 91 4 stroke you will be able to turn a 14" prop
rather than a 12" with a 2 stroke.
Having more torque also means more flexibility in prop/pitch choices across the power band.

2 or 4 Stroke??
 

I took a Magnum 46 out of my Extra and replaced it with a Saito 56 and had to add weight to the nose, that surprised me. My Extra now is a fun plane to fly. I agree with Minn I won't buy another 2 stroke because I love sound of 4 stroke. I bought an OS160 twin for my Stinson, I can't wait to hear that. Another thing I like about my Saito 4 strokes is if I just want to putput around I run 15% when I want to rip I run 30%, yeeehaaa

2 or 4 Stroke??
 

The same size 2 stroke is heavier than a four stroke because of the heavy stock muffler. Also manufactures make the two strokes much heavier than they used to.

2 or 4 Stroke??
 

I find 4-strokes respond quicker (the plane in flight) because they produce all their power right away, low in the RPM range compared to a 2C. This helps the plane speed up quickly - almost the same as a large diesel-powered truck's low-end grunt as opposed to a small car's higher top end, but slower 'off the line' punch.

It may not seem important, but one weird thing I find with 4-C's is they also -slow down- quicker. Dunno what to make of this, but it can be useful - maybe something to do with a larger prop? But I'm not sure.

OK. The winner to me is always going to be a 4-C. I don't care what the box your ride came in says - a .60 2C and a .91 4C DO NOT NOT NOT NOT make the same amount of power. TRUST ME. If they -DID- someone explain to my why my lead-sled YS .91 blows my US-60 straight to mars, while my .65 Magnum just kinda tugs it around the sky? I'm propped RIGHT ON for my .65, and probably a little under-propped for the .91. With the 91 i have unlimited vertical, with the .65 I have vertical... sort of.

For your trainer. Go with a 2-stroke (2-strokes and 4-strokes compete evenly when smacked into pavement at 60mph). For your max-velocity race planes - go 2-stroke. For -everything- else there is bound to be a suitable 4-stroke that you'll be happier with over a 2-stroke.

2 or 4 Stroke??
 

Uhhh.... Like.... That there YS is supercharged, dood. :)
Compare it to a supercharged .61 2-stroker.

With the help of a couple small turbos, my little 3 liter auto engine puts out about 450 horsepower. Wouldn't be fair to compare that to a 2-liter 2-stroke normally aspirated engine, would it? ;)

2 or 4 Stroke??
 

True, I had an OS 91 Surpass on my Skybolt and it flew well. 4 years ago, I switched it to a YS 91AC, and now the thing is a rocketship! Woo Hoooo!

And BWT, rc-sport, you're gonna LOVE the sound of that 160 twin!!

2 or 4 Stroke??
 

Yea Iknow Minn, now I just have to find someone to finish building it for me.

2 or 4 Stroke??
 

I use all 4 stroke engines and have no tank larger than 10oz.
they are much cleaner, quieter, and for my money just as relieable
I have never ran out of fuel My biggest engine is .91 as I don't see much use in spending large amounts of money on big engines When I can have just as much fun with 40 to 91 size

2 or 4 Stroke??
 

rc-sport,

Well, it won't be long before winter is here. That should give you a little more time to build.

BTW, I hear there's a big show coming up in Chicago. Where can I find some info?

2 or 4 Stroke??
 

Minnflyer, You mentioned in two of your post that 4 strokes are cleaner.



That's totally the opposite on my end, I find that the 4 strokes make more then double the mess on my planes then my two strokes do.


Now maybe its just the smaller four strokes that are cleaner or maybe its the brand of 4 stroke, who knows as I run 100's and up. I have three, 2 strokes and two four strokes and the 4's leave by far more of a glob of waste on my plane then my two strokes do. Maybe its because they have to run richer then the two strokes *shrugs* I have one Saito 100 and one OS 120 FS that has yet to be fired up. All I can tell you is my Saito 100 leaves a pile of gue on the bottom of my Edge.

Randy

2 or 4 Stroke??
 

Minn, the show coming up is the RCHTA show on Sept 8th, I believe. Its one day only open to the public, it used to be 2 days. Its held at the Rosemont Convention Center in Rosement, plenty of hotels in the area. When I get more info I'll let you know.

2 or 4 Stroke??
 

'Da 65 iz piped man :) And that's not a supercharger per se, but it crams air into the engine... so I guess it has resemblences....