Don't think its the reading. I really don't get the point of the whole tirade. Snob appeal isn't necessarily bad. You can get the best and latest or most expensive RV, or the latest and most expensive SUV. I think the SUV has more snob appeal even though the RV costs more. The YS has more snob appeal than a Jett even if the Jett costs more. But that won't keep me from buying a YS if I need one.

Well, I don't see buying what I like as snob anything. I'm not the one who was looking down his nose at anybody's purchases. Some folks look at 4 strokes as excessive, and YS as excessively excessive. I don't. I own both YS and Jett engines. I consider the Jett a much more excessive expenditure, but I feel like that's kinda the purchaser's business.

.......This just in..........

YS and Jett are worth every penny-

It's like I heard an old welder say "If everyone liked the same thing they would all want his wife" I have 2S and a 4S and I the only 2s I will buy in the future will be gas. I am buying a YS 120 from a club member to go on my Goldberg Extra 300 to replace a 1.08 magnum and can't wait to try it!

How come there are no 4-stroke gas engines? A 4-stroke gas engine would sound awesome.

there are some conversions out there, but gas in general has a lower power/weight anyway, so a 4 stroke is a very heavy engine.

2 strokes to 4 huh well I have owned both and my 3rd plane I put my first 4 stroke in I was 22 years old at the time. I had no issues rule of thumb 2 stroke = high speed high rpms 4 strokes= tons of torque less speed lower rpms. Spooling time in a 2 stroke is slower than a 4 and you wont get the pulling power from a 2 you will with a 4. I am partial to 4's I have owned quite a few and I am not by any means a "gear head" I know the basics and consider myself to be more a geek on the physics side of planes props and flight characteristics. I have never had an issue with any of mine. I had OS, Enya, YS and Saito all 4 strokes. Dont get me wrong I have never had any issues with my 2's either i just prefer 4's. Good Luck. Try a 4 stroke you may never go back

To Richard L. I have seen some fourstroke gas weedeater engines. They do have wet sump oil systems. The pushrod tubes and valve covers look like our glow fourstrokes.

I have one of those 4-stroke string trimmers (Troy Bilt). Its a nice running engine, sounds good, and at somewhere 26cc it has got to be about the same weight as my Brison 3.2 (52cc) and I doubt it puts out near the same power. The specs list the operating RPM at 6800-7900.

The little Honda GX25 is a lightweight overhead camshaft 25cc trimmer engine with a reasonable performance.

It does not use oil in the fuel, and has what appears at first glance, to be a wet sump.
However, this is not the case, - the oil is held in a circular tank at the rear of the crankcase (but seperate), where it is whipped up into an oily mist by an agitator, and then distributed throughout the engine by the pumping action of the underside of the piston combined with one way valves, and returned to the tank.

This is a very simple and inexpensive system, which causes no pollution ( no oil in the combustion chamber) and is suitable for model aircraft because it can be used at any attitude, as in a 2 stroke.

This motor could probably be made to produce a lot more power (if necessary).

PS . - this is not a glow engine of course, but worth a thought, ( no oily mess, 0% oil in fuel,as opposed to 18% in glow engines!! ) takes some beating!

Willdo,

....that sounds very interesting. As soon as someone makes up the prop
adaptors....the OHC Honda might be a very nice engine....[sm=thumbup.gif]

Ralph Cunningham at RC Ignitions has done a prototype hub for these.

I'd agree with a lot of folks here that it pretty much comes down to what you want to do. I have a .48 4-stroke from OS and love it (even though it's very aged and is beginning to act strangely), it's just great on my Cub. I've always liked the sound of 4-strokes but didn't used to think they necessarily sounded more like real planes. But after flying my .48 on my Cub the way it's MEANT to be flown (slow, throttle waaaaaaaay back) I'd have to say it does sound a lot more like a real plane at times than a 2-stroke. And I gotta mention the smoke.........this probably varies depending on the manufacturer, and maybe it's not a big deal to most people, but I kinda get a kick out of the stream of white smoke my Cub throws out when bumping the throttle a bit for a go-around (from idle to about half usually), or revving up for takeoff. It just looks neat.

OTOH, a hot sport plane with a screaming 2-stroke can't be beat! Plus they really are simple, and lots of power in a small package. I like 'em both, though if money were not an object I would definitely have more 4-strokes in my hangar, especially since I prefer scale models.

-Matt Bailey

When I got into this hobby, I started with a 2-strk (OS .46FX) on my trainer and had a blast with it and still love it (now on a Superstick built for speed). I bought a YS .91FZ for my second plane to try a 4-strk and I will tell you, I haven't look back yet at 2-strks. I have only bought 4-strks since. I have a OS .46FX, YS .91FZ, YS 1.10FZ, Saito 40 and a 40 LA that was given to me after a club member bought a Magnum 52 (4-strk) for his trainer. Another converted happy 4-strker. LOL...

4-strks are so much better and less messy. I fly 3D and 2-strks just don't have the low end torque that is needed for this particular type of flying IMO. The larger 2-strks are better, but I would rather have a 4-strk or simply go gas. My OS .46FX on my superstick is a lighting rod with wheels. I think the best place for 2-strks are on trainers (cost less) and on speed planes because you want the high RPM's.

I say go for a 4-strk and really learn what flying is.

BTW, the 40LA that was given to me is still setting on the shelf collecting duct.

Happy flying
DTB

It seems that I have the best of both worlds. I use a simple 2 stroke but run it in a 4 stroke

Not quite with you there mate??

When people say four strokes have more torque or power they are compairing apples to oranges. That is they are compairing larger displacement four strokes to smaller two strokes. A .91 four stroke will usually have more torque than a .61 two stroke and with the same or slightly more power. They are as light as the two stroke. Modern two strokes are lighter and better at low torque power. For example the newer .91 and larger two strokes are lighter than the older ones and almost as light as the four stroke. They are more powerfull and have more torque than the same size four stroke. On the high end the OS 1.4 is equal to the YS 1.4 and the fuel injected version is now the pattern engine to compete with.

Yes two strokes can be designed for either plenty of torque, or for very high power, this all depends on compression ratio, carb size, port height and pipe dimensions etc, and how they interact.

Same with four strokes, - depends on cam design, compression ratio, carb size, exhaust length, number of valves etc.

Not so sure about 4 strokes being lighter though, they've got more parts! but I guess two stroke pipes could be a bit heavier. ( correct me if I'm wrong ).

It's easy to say that 4 strokes have better torque than 2 strokes, but this is a just a simplistic and general description.

Sound? well I'd probably go for the 4 stroke.
Power to weight ratio? I'd go for the two stroke.

In my application I use 2 strokes but run them very rich so they 4 stroke. A light and simple engine with (almost) that nice 4 stroking sound. Their porting is timed for high torque at low revs and run just lovely on a tuned pipe. My Bolly CF pipe weighs 2.7 ounces and the Eather CF pipe weighs 2.0 ounces.

Before or after being filled with oil? - joking! [>:]

I started out with 4S from the first plane I bought. It had an O.S. 26 Surpass and flew just great. After that I built a Goldberg Freedom 20 and used the same model engine and loved the performance. Then a Decathlon with an O.S. 70 Surpass and it was off the ground almost immediately. I always liked the low end torque of the four stroke. I got out of the hobby for a few years and am now getting back in. To get started quickly, I bought a Nexstar ARF with the O.S. 46FX. Although the engine has lots of power for this plane, it does take a longer takeoff roll for the engine to build a little power before lift off.

I am now building a GP Ultimate Bipe and am planning to use a Saito FA-72 4S in it for power. For my money, the 4S is hard to beat in performance and the maintenance is minimal. Of all of the 4S engines I have owned, I am yet to need repairs on any of them.

Sport and Willdo make some good points above.

Engines can be designed for specialized tasks, and often are.

In the case of Jett.....yeah..... the basic SJ-46 or SJ-50 will scream on its standard muffler or even run stronger on a full pipe.....well over 17K rpm. The 90L is the same way..... will howl over 15K rpm if set up correctly for a speed application. By changing the muffler, changing a pipe length, or a few other small adjustments, that same SJ-46 will be happy turning a 12x4 at 14K rpm......... or turning a 9x7 at 18K rpm.

But then there is the 60L, 65L and 76L. Same "40" size engine..... about the same weight.... different animal. The 1.0L and 1.20L compair to the 90L in the same way. These are designed for lower rpm, bigger props, intended for 3D, aerobatics and scale applications. They feature carbs and crankshafts designed for the job, include unique port timing, and are designed to run with 'untuned' lightweight mufflers. The BSE-76L is essentially a "40" size engine designed to turn a 14x6 at 10K rpm and provide a smooth power curve from idle to full throttle.

Yes, Jett engines are know for speed, and above all else quality. But the newer generation of engines are designed for 3D, aerobatics and scale applications where power-to-weight and integration into the aircraft are the most critical.

Every application is not the same, and engines are not the same. I own a variety of engines both 2C and 4C. Would you use a Jett 46 on a trainer? Not normally... Would I use an OS70FS on my F-20........ probably not. On my P-51.......currently powered by a SJ-46 turning that 12x4 prop. Plane would fly just as well with an OS70.... so its a toss up. On my 1/4 scale cub..... that OS FT-120 is RIGHT at home there.

Maintenance wise, a well designed, well built engine of any type will last a long time. If the engine includes 'inexpensive' materials or less-than-optimal bearings...... those tend to be the limiting factor. The value of an engine tends to involve much more than its selling price.

Bob

Four- stroke ... two-stroke ... Oh, what the heck!!!!!!!!!!! love them all !!!!!!!!!!!!!

Ford pickups are better than Chevy pickups! Everybody agrees with that.

I agree with Panda

Heck, I started with a rubber band model..... if the prop keeps turning more than 90 seconds, thats till way ahead of where I started