2 stroke vs 4 stroke
 

I have recently been looking at all the Hangar 9 ARFs and was wondering why most people are going with the saito 100 vs any of the recommended 2 strokes. What is the big advantage? Does the 2 stroke have as much power? The only thing I could think of was the difference in sound and maybe prop size. Anybody have any other ideas?

RE: 2 stroke vs 4 stroke
 

I am not a Saito owner, but I do prefer four strokes over two strokes.
Four strokes have a quicker and a much more linear throttle response which makes flying some planes easier.
The sound is more pleasing to my ear.
10k is a lot of RPM for a four stroke so prop noise is reduced.
At one time I never thought that I would ever even consider four stroke engines, then I got one and now that is all I fly.

RE: 2 stroke vs 4 stroke
 

Well, most folks aren't. At least around here.



Advantage? For which, 2 or 4?

The advantages of a 2 are many:
Lighter
Less parts (wear, breakage, maintenance, adjustment)
Almost always cheaper
More powerful
No special nitro content required
and a few more

You've pretty much covered the advantages of a 4.

RE: 2 stroke vs 4 stroke
 

Myths about 4 strokes.

They do not weigh more than 2 strokes.
They don`t take special fuel.
2 strokes don`t make more power. More noise and mess with a 2 stroke.
The advantages of a 2 stroke over a 4, they are cheaper.
4 strokes burn less fuel.

RE: 2 stroke vs 4 stroke
 

The following are not ideas, they are facts. Price and maintanence is up tp the individual to decide what he/she wants. For any given size the four stroke will be heavier.

Now for the important stuff. For a given displacement the two stroke will always produce more power and torque than a four stroke. That is a fact and I will not argue about it. Where this higher two stroke performance can be used is a different discussion.

The four stroke engine has the ability to turn a larger prop at a lower rpm than a two stroke. That is purely a charictaristic of the engine. That ability is a result of the relationship of the rpm (measurable), torque (measurable), and horsepower (Calculated). That makes the engine eminently suitable for lower speed manouvers/aerobatics with the appropriate aircraft.

Ed S

RE: 2 stroke vs 4 stroke
 

quote]ORIGINAL: chashint

I am not a Saito owner, but I do prefer four strokes over two strokes.
Four strokes have a quicker and a much more linear throttle response which makes flying some planes easier.
The sound is more pleasing to my ear.
10k is a lot of RPM for a four stroke so prop noise is reduced.
At one time I never thought that I would ever even consider four stroke engines, then I got one and now that is all I fly.
[/quote]

I am in the same boat. When I started in the hobby I thought I would never buy a 4 stroke. I just couldn't imagine spending that much on an engine. 2 years ago I bought my first 4 stroke and since then have bought 4 more. By the time I finish my current projects of my 5 flyable planes only 1 will have a 2 stroke.

I dont know why I like them so much better but I do. I like the way a 4 stroke powered plane flies and I really like the sound. More and more I have begun to really dislike the sound of a 2 stroke. Also, because of muffler design and such, 2 strokes seem to slime planes more than the 4 strokes.

RE: 2 stroke vs 4 stroke
 

BTW, 4strokes are way kewl.

For whatever reason, a lot of people are really passionate about them. They seem to enjoy the hobby more because they have those 4strokes to play with. And that's the beauty of our hobby. Different strokes for different folks.

But there are real and true differences.

If ya' like either, the hobby has room for ya'. Even if you like both.

So if you're actually wanting to know if you might enjoy using one, try one and see. That's the other wonderful thing about our hobby. We can try just about anything. ;) And not need a government contract to be able to do it.

RE: 2 stroke vs 4 stroke
 

But you do need your wifes permission.... which is sometimes harder to obtain;)

RE: 2 stroke vs 4 stroke
 

I think OS is changing things up a little with their new AX series, they seem to be designed more for low end torque. Compare specs on the same displacement and I think the 2 stroke has a definite edge.

OS 120AX
Displacement: 1.218 cu in (19.96cc)
Bore: 1.197" (30.4mm)
Stroke: 1.083" (27.5mm)
Crankshaft thread size: 5/16-24
Practical RPM: 1,800 - 9,500 RPM
Power Output: 3.1ps/9000 RPM
Weight: 22.82oz (647g)
7.074oz (219.2g) with 90° adapter installed
7.907oz (245g) with extension installed
Propeller: 15x10-12 or 16x8-10

OS FS-120 III Surpass
Bore: 30.4mm (1.20")
Stroke: 27.5mm (1.08")
Power Output: 2.1 BHP at 12,000 RPM
Practical RPM Range: 2,000 - 12,000 RPM
Weight-Without Muffler: 32.5oz (921g)
Weight-With Muffler: 35.3oz (1000g)
Crankshaft Thread Size: 5/16-24
Valve Clearance: Between .04mm and .1mm (or between .0015" and .004",
measured between the valve tip and rocker arm)
Length: 102mm (4.09") from backplate to the front of the drive washer
Width: 47mm (1.85") width of engine neglecting the mounting flanges
58mm (2.28") distance between the mounting hole centers
Height: 139.5mm (5.49")
Suggested Prop(s): 14x9, 14x10, 14x11, 15x8, 15x9, 15x10, 16x6,
Construction: Aluminum and Aluminum alloys

In this case the 2 stroke is lighter, spins the same prop sizes, and has a lower practical RPM range. As far as burning fuel more efficiently however a 4 stroke will always be top dog, so buy the 4stroke and save money later or buy the 2 stroke a save money now.

RE: 2 stroke vs 4 stroke
 

the 4s will be slower if that matters, they don't unload as much.

RE: 2 stroke vs 4 stroke
 

The gospel truth according to the Two Stroke fanatic:
http://mypage.yhti.net/~dmcdnld/4cycle.htm

The gospel truth according to the Four Stroke fanatic:
http://mypage.yhti.net/~dmcdnld/2cycle.htm


The rest of us will fly what makes us happy.......regardless of the number of strokes.

RE: 2 stroke vs 4 stroke
 

To me it comes down to this:

If you compare their statistics side-by-side, the benefits of a 2-stroke outweigh a 4-stroke. (Picture 1)

But in reality... (Picture 2)

RE: 2 stroke vs 4 stroke
 

I have to agree with MinnFlyer here. You can quote specs all day long but in the end I believe it's almost always sound in the air and while in the pit.

Economy of operation? Phtttt! If I were interested in saving money I wouldn't be involved in building and flying RC (:-).

RE: 2 stroke vs 4 stroke
 

Yeah, there's nothing like the scream of a small prop on a piped 2-stroke!

I own a bunch of both types. Some are good for some things and some for others.

RE: 2 stroke vs 4 stroke
 

You are right that we can try just about anything .... heck I even know some people that put motors on their planes instead of engines. Now those motors really do sound funny. :D

RE: 2 stroke vs 4 stroke
 

So that's where that quote came from. I've been wondering that for years...