does 3d doen better with 4 sroke engine ?
 

Correction I never specified that 2 stroke glow was the best, I am just a 2 stroke fan in general... GAS or GLOW. I just don't have a plane big enough to justify a gas engine. But do realize gassers are ALL 2 stroke. I wish I could fly today. Maybe tomorrow. ;)

Power...
 

A 4-stroke IS more powerfull then a 2-stroke! Why? Because of much better cilinder filling.
Now why does a .60 4-stroke put out less power than a .60 2-stroke? Because it has only half the number of combustions. That's why it is more economical on fuel. Compared combustion stroke per combustion stroke, the 4-stroke wins hands down in the power department!
When
not
running a tuned pipe on a 2-stroke, you be surprised of how much fuel washes down the exhaust without being used.
The only reason our 2-strokes perform the way they do, is the fact that it is easier (cheaper... :rolleyes: ) to make a high revving single cilinder 2-stroke.
The only thing lacking in our engines (2 as wel as four strokes) is ignition. From a tech point of view, glow is a horrible system...
Our 4-strokes could put out a lot more power with a proper ignition, because we could increase compression ratio dramatically...(so this is exactly what I'm going to do to my next 4-stroke)

does 3d doen better with 4 sroke engine ?
 

Who cares about how strong a combustion stroke is? I care how fast my prop is turning. You just admit it yourself rudeboy a .60 size 2 stroke is more powerful than a .60 size four stroke. Not to mention a .90 size 2 stroke that is the same size and weight as a .60 2 stroke. Whenever 4 strokes get some kind of ignition we'll see, but as for now the numbers speak for them selves. In my opinion high dollar 4 strokes are just status symbols. :p

does 3d doen better with 4 sroke engine ?
 

Some cases, two strokes are better, others, 4-strokes are. I don't know why people are not judging the VERY best 2 strokes (OS), against THE VERY best 4-strokes (ie YS). I know I praise them alot on this forum, but it is true, YS are simply the best 4 bangars. Anyway, if you look carefully, the YS DZ will be very near to the OS 160 in terms of revs, seeming as thats all everyone wants here. Yet, it is smaller.......For 3D, it has a pump, it is damn reliable, throttle is smoother than silk, and it has torque in all ranges. The two stroke, isn't! Throttle isn't as linear, alot of feul is bypassing the whole combustion, and just runs out. I noticed that the exhaust on twos is much wetter, than 4 strokes, which is just smoke. Also, when you look at the smaller two strokes, with people running them at about 15,000 RPM or more, alot of power is being wasted. A guy put it like this. Air, is like ice. Put a dodge viper and a mini on tarmac, and bring them both to full power, who will win? now, put them on ice, and put them at full power, now who wins? The dodge, (which is the prop in our case), has too much power going through, and it is sliding all over the place. So don't be too sure that your prop spinning faster is translating into more air over your surfaces faster. Lastly, look at weights of engines, you'll find that four strokes have a larger displacement, but are the same weight or lighter than small two strokes. Take a YS 63 and an OS 60. The YS is bigger, but lighter. Infact, it is nearly the same as a 46FX, (but still heavier), yet has FAR MORE RAW POWER. So it is not fair to compare a 60 2, with a 60 4 stroke. The YS 110 or the saito 100 are lighter than the 91 FX, (I think!) Yet, have more power. Lastly, for hovering planes at lower throttle, the torque of a four banger is IMO alot better to live with!

does 3d doen better with 4 sroke engine ?
 

Really interesting Robert.

I don't understand why 4-strokes are often lighter than 2-strokes. From what I understand, a 4-stroke doing only one fire every 2 revs mean a real big bang (needing here more solid parts) as for 2-strokes, a smaller less efficient fire every rev (less stress to parts so smaller are required). Just wondering how can an engine with more than twice the parts and higher stresses involved end up lighter.

$$$
 

Mugenkidd,

I'm just a working class guy...If you think I put a 500$ 4-stroke on a plane instead of a 250$ 2-stroke to have a status symbol...you're wrong. I have no status to symbol :D :D :D If I had the cash I'd use even more 4-strokes.
I can't talk for someone else, but for me, my 4-strokes are the most powerful, quiet, reliable, smooth, easy to operate and install engines I have ever had. The only thing I use 2-strokes for is speed, because it's easier (again cheaper :rolleyes: ) to increase power output on them and because variable pitch props are not available yet ;)

does 3d doen better with 4 sroke engine ?
 

Simple: an engine built to do 10K rpm can be built much lighter than one built to do 17K.
The "bangs" on a four stroke aren't bigger, they just last longer... Combustion strokes on a two-stroke are very short and combustion power has to be transmitted to the system in a very short period of time. Combustion strokes on a 4-stroke typically last 160-170 degrees, so there is much more time to transfer power (hence: more efficient).

check your numbers Rob
 

Ok Robert if you are going to compare figures be sure you know what you are comparing.

The OS .91 fx is lighter than a saito 100 the saito weighs 20.8 oz w/out muffler and a .91 fx is 19.4 oz without muffler. The comparison that horizon hobbies has on there website is between the OS .91 FOUR STROKE and the saito 100 FOUR STROKE. check the numbers I listed earlier and the ones on the horizon site and you will see the the .91 fx will out perform it.

As for the YS vs the 160 lets compare apples to apples, put a pumper on the 160 fx and see what you have. Obviously you have no experience with a 160 fx, it has silky smooth throttle response and great low end. How bout we have a 3d competition with our planes......... thats even if you own a YS DZ. :devious:

As far as the "power loss" analogy goes "PLEASE" all of your colleges already agree that four strokes are for flying SLOW. If 2 strokes are wasting so much power how come no competition quickee plane or for that matter any other type of race plane, or to broaden the scale any other type of competition helicopter or r/c car are using four strokes? :confused: If four strokes are so great how come there are no gasser ones offered?

Sure I will agree that 2 strokes are not very fuel efficient but I have never seen any high performance engine that is. Last time I checked the guy with the Dodge Viper didn't car how many miles per gallon he was getting, NEITHER DO I.

Four strokes are a novelty item for flying slow. pirate:

does 3d doen better with 4 sroke engine ?
 

From OS engines, and YS performance.

OS 61Fx.....19.4 oz 2,000-17,000RPM
YS 63.........17.9 oz 2,000-12,000RPM

What Rudeboy said is true, an engine has to be ALOT stronger to withstand 17000 RPM than 12000RPM, and, as there are only half the amount of bangs, I presume that there is alot less forces acting on it. (Although I am only presuming). I was just pointing out that we should also be comparing power to weight ratios. As you can also see on the OS engines page, the maximum power output is at 16000RPM. As I said earlier, a prop at that speed will be just slipping the air, not biting it. Also, one of the big props that everyone uses, will load the engine down to about 9000~11000. That means that the maximum power available will not pass through the prop. If you look at a power graph in magasines, you will see that a two stroke gets most of its power at VERY high throttle settings, hence the graph is flat, and then gets steeper. But a four stroke has much nearer to a straight power curve, with all the available power available at lower RPM, an RPM that is usually used in a plane.
Anyway, I think I am going in too far. In short, both will do, for different applications.

does 3d doen better with 4 sroke engine ?
 

rudeboy,

adjust your valves all you want to there is no form of R/C competition that a 2 stroke engine can't compete and win over a 4 stroke including 3D.

:boxing:

Charts are showing horse power
 

The charts show horse power, which yes peaks at the high RPM's but the peak tork is not at these rpm's, the peak tork on a .91 fx is around the 10-11k which will work just fine for larger props at lower rpms. OS recommends that this engine uses a prop that causes it to peak at just over 10k RPM.

Man I wish I could be flying now. :bananahea

does 3d doen better with 4 sroke engine ?
 

MugenKid, I was staing my facts on what I knew, and the stuff I wasn't sure about, I told you, like the weights. For 3D, you don't want the plane to go fast, you risk structural failure if you do so. I saw the UCD warning, saying not to use a pitch greater than 6, or else, the plane will break. I do have experience with both engines. I haven't owned them, but yes, I saw them, and I researched them. Alot of pilots I've talked to have BOTH, and most agree with what I said. Have you 'experienced' a DZ yet? Its very good that cars and helis etc. use two strokes, but the one you missed, is the one in question, 3D, and I firmly believe 4-strokes are better. Why are YS's used so much in F3A and AA, if they are only four strokes?
Anyway, this is turning into an attack, which is not what we want, so apologies if I went off track.

I love you man
 

Robert,

I am not trying to attack anyone, I just have cabin fever we have had snow and I have been having to work too much. I knew attacking 4 strokes would cause an uproar and be a lot of fun, nothing else. I personally will never own a four stroke but I could care less what everyone else flies, I just personally think they are overrated, but they are quieter. ;)

I love you too!!!
 

:sunsmiley

does 3d doen better with 4 sroke engine ?
 

As I said much earlier,fly what ever you want,this is a fun hobby/sport and as long as a person is having fun,who cares if the plane has a John Deere engine or a rubber band.

Re: check your numbers Rob
 

Oh my god!!! Mugenkidd, do you fly that engine without an exhaust??!!! ;)

Ever compared muffler weights 4 vs. 2-stroke? :confused:

does 3d doen better with 4 sroke engine ?
 

I Robert, have you flown your DZ yet? I bough one over a 160 FX and hope made best decision. To be honest, I have not been impressed too much of the 160 and haven't even seen a 140 DZ in flight. It is my first 4-stroke and always wanted to stay with 2-strokes but this one was real cheap.

does 3d doen better with 4 sroke engine ?
 

:) In between arguing with you guys about engines I'm brainstorming on my next plane. A DH-88 Comet: a golden era twin engined race plane... I wonder what engines I'm going to put in this one... A couple of .60 two strokes maybe?

does 3d doen better with 4 sroke engine ?
 

I don't consider it arguing, more than debating. And I like debating, so to me, this thread is fun.
3D Joy, I don't have a DZ, YET. I have an L, and boy have I fallen inlove with it. I am really thinking though about the engine for my pattern plane some day, I really like the 140RX, I really love the 140 RX F1 (who doesn't like gadgets?), but I REALLY ADORE the dingo, but the last two are VERY expensive, so I might have to go with the RX.....

does 3d doen better with 4 sroke engine ?
 

Well, uhhh, I meant that in a funny sort of way...

By the way, I will be putting 2 Laser 80's on that Comet...

does 3d doen better with 4 sroke engine ?
 

WHAT'YA'MEAN 2 LASER 80s????????? Stick on two 3W 150.......Sheee......BTW, I knew you were messing....:D

OK
 

Ok, that one's for next winter. I'll just enlarge the plans 3 times and put on the 3W's...

LOL :D :D

does 3d doen better with 4 sroke engine ?
 

yeah, I wouldn't put them there 3W's on anything smaller than 80 inch.

does 3d doen better with 4 sroke engine ?
 

As TerrellFlyer said it's just about what you like , 2 or 4 strokes as long as they do a good job is what matters,, and people often argues about an engine type or airplane based usually on a bad experience, after all, they are very expensive toys and nobody wants to have one you don't like. i.e. I have a JR10X and did not get the Futaba not just for the software(both have more than most people will use ever), I got it because I like it!!.

Rudeboy LOL
 

:D I admit I was just trying to get everyone typing, I was bored and wanted to get this thing as long as possible. I know that the .91 fx was heavier with the muffler, but Roberts responces really made my previous one look like I did know what I was talking about. I had to stand up for my 2 stroke debate, it seems like I am the only one on that side. You guys fly the heck out of those 4 strokers more power to you (less than a 2 stroke though) LOL :D . One of my R/C role models loves 4 strokes. I just can't get into them myself. I love to debate its great fun. No one take anything personal, I'd rather fly than argue but I have been unable to so here I am, hopefully we can all do this again soon.