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?

Noise is the only other factor I know of.

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

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.

How about COST? *%#@*

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

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!

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

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

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!!

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.

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

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 .

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

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.

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*

"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.

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

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

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.

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.

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)

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.

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

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!

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

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.