Jetdesign

My Feedback: (8)

I figure I'd post this here 'cause you guys 'know me' the best and know where I'm at...

I need an engine for my plane - a sub-9lb. 69" Yak. This plane was bought to 'balance out' my fleet - my other 'go-to' plane is a Venus II with a 120AX. I'm hoping the Yak will end up in some IMAC meets and open the door to some more '3D style' aerobatics, but not really looking for all out 3D. As most of you know, I just finished up my first season of flying and am really into pattern. So far I only have experience with OS's AX engine line and am DYING to have a four stroke. I figure I'd post [link=http://www.youtube.com/watch?v=TQgs4OWmY8s]a link of some flying[/link]. FYI it's a new (untrimmed) plane, new radio, new engine, and new field, so it's a little messy. Here are the options and my thoughts:

OS 120FS $350 and a $40 rebate: I love OS (ease and reliability) and Hobby Services, as well as Tower Deals. May lack the power I'm looking for?

Saito FA-125 $390: I've been told this engine goes well with the plane by 3D pilots. Running on the expensive side since there's no Tower Deals and free shipping. I feel like if I'm gonna spend this much ca$h, I should just go for a YS.

YS FZ110 $370: Gobs of power; always have the option of putting this one on the Venus if I wanted to. Runs on expensive fuel and is more of a handful for a first four stroke. Probably my favorite choice (thinking the OS isn't enough power) and feel that I'm gonna be running a YS one day, just not sure if I'd be jumping into it too early.

OS 120AX $270. Old Reliable, least expensive, and great wide open power. Just not a four stroke.

Thanks for your thoughts!!! I really appreciate any input based on what's right for me, and not just your favorite choice

alfredbmor

Considering, that you want the feel of a four stroke engine, and that it should do a 3D job, I easily would pick the YS.
All others are fine engines, even easier to tune and maintain but the YS is a hard to beat performer in the 3D area.

jetmech05

ever thought about gas? a 20 cc is a 120..and cheaper fuel...

Rufcut

Oh, to have your problems! Get the one you like the best, the YS. It's not even the most expensive. Besides, from what I've read on these forums, "jumping into it too early", is not a problem for you. Happy flying!

MinnFlyer

My Feedback: (4)

The YS is the most powerful, and will run very well on 15% cool power (I use 15% Cool Power for everything just so I only have to use one fuel)

But it is also the most finikey.

Since it is your first 4-stroke, AND you're already familiar with the reliability of OS, I would recommend the OS 120FS

JohnBuckner

My Feedback: (1)

1. Go the YS

2. Educate yourself to its operation

3. You will never regret the purchase

bigedmustafa

My Feedback: (2)

I voted that you should go with the O.S. Max 1.20 FS Surpass. The O.S. will have plenty of power no matter what people might otherwise claim. It's also going to be the most user-friendly four stroke on your list, so it's a good choice for a first four stroke.

If I were choosing for myself, I'd probably select the new Thunder Tiger F-130s that Ace Hobby showed at the iHobby Expo in Chicago last fall:



Thunder Tiger is usually best in class with regard to overall value and performance. It's a shame that their outstanding line of four stroke engines is too often overlooked.

Good luck and good shopping!

ChuckW

YS is the best performer I think but I voted Saito 1.25. Actually it was a tie between that and the OS 1.20. Why not YS? While they run like a striped a** ape, they can be more finicky to set up, tune and maintain. Don't get me wrong, it can be done but maybe just not the best idea for a first 4-stroke.

I do like the looks of that Thunder Tiger too. I may have to check one of those out someday.

Jetdesign

My Feedback: (8)

Two stroke OS or four? I like the TT too, but I haven't seen one for sale yet, and have only seen their retail prices published so I have no idea where to get one or if I can afford one.

FLAPHappy

My Feedback: (209)

I am going with the YS, with 30% Nitro. It's more power than you can imagine.

ChuckW

Four stroke. Maybe not the best choice for 3D or anything but it'll be a very reliable engine with plenty of power for standard aerobatics. The Saito will also be extremely reliable and a pleasure to own after it gets broken in.

bigedmustafa

My Feedback: (2)

If your local hobby store doesn't carry Thunder Tiger engines, then a few of the better online sources are:

http://www.thundertiger4u.com

http://www.infinitehobbies.com

http://www.ehobbies.com

http://www.paulsmodelsupply.com

http://www.radicalrc.com

I've purchased Thunder Tiger products from all of the companies above except Radical RC, and I've been happy with the service from all of them. I'm sure I'll buy from Radical RC someday, too. Infinite Hobbies ships orders over $100 for free, while thundertiger4u.com ships orders over $150 for free. Any four stroke engine order should qualify for free shipping from either reseller. While who has the best price on which particular engine may vary from time to time, Thunder Tiger four strokes generally price out as follows:

TT F-54s - $169.99 to $179.99

TT F-75s - $169.99

TT F-91s - $184.99 to $194.99

The model number for the F-130s will be TTR9805. While it was shown at the iHobby Expo, no official pricing or release date has been set yet.

Thunder Tiger four strokes are sometimes criticized for being heavy, but only the F-91s is heavy in comparison to similar competitors. The F-54s and F-75s are actually about as lightweight as Saitos of similar displacement.

The F-91s weighs in at a whopping 25.7 ounces w/ muffler while the O.S. Max .91FS II Surpass weighs in at 24.2 ounces with muffler, the Magnum XL .91 RFS weighs 22.4 ounces, and the Saito .91 weighs 19.6 ounces plus muffler (around 21 ounces or so with muffler). Considering the lightest engine in this same displacement category is only about four ounces lighter, the F-91s isn't that much heavier than the competition. It's often a good choice for scale projects or planes with long tail moments like the Goldberg Tiger .60 that benefit from a little extra noseweight when it comes time to balance the CG.

Ace Hobby provides all warranty service for Thunder Tiger engines here in North America. Thunder Tiger parts and service are provided worldwide and all Thunder Tiger engines come with a 3-year parts & labor warranty.

Jetdesign

My Feedback: (8)

Does the OS four stroke have an outlet on the back plate? If so, can it be used (with a 'T') to power a Perry Pump?

I just checked the reviews of the TT .91 four stroke and I'm a bit put off; not many happy customers. OS is starting to look pretty promising. YS is up there too, but trying to sift through what I've seen and heard and decide what's first hand info, and what's bandwagon myths.

Right now, my understanding is that YS actually has a supercharged system, so to speak, that forces not just more fuel but MORE AIR into the chamber. This teamed up with high nitro means A LOT of stuff to burn in the engine, resulting in more power and fuel consumption.

3D guys like four strokes, and the plane I've got is a 3D plane. Thus, Saito is a top engine of choice because it weighs less. I think a lot of people have been avoiding the OS just because it's a few ounces heavier. People say that Saito has more power, but I bet that's mostly hear-say. I've seen two reports of actual owners of both brands with a tachometer that show OS swinging props a few hundred rpm faster.

The OS four stroke is the engine of choice for 10-12, and even some 15lb scale planes; it must have some power. There is a review of the Hangar 9 Showtime, tipping the scales at 10lbs, nearly a pound greater than my plane and still flying some 3D stuff.

I think the hardest thing for me has been that generally people with similar planes and four strokes don't fly like I do; I'm not looking to hang on the prop all day. I have yet to see the Saito or OS in a video with greater than a 6" pitch, and many of them have been 4W's. I'm guessing I will be somewhere around a 15x8, 16x7, or 17x6. I"m hoping to fly big, possibly fast, and possibly a little prop hangin' just to get my feet wet.

I think I need to get a life[&:]

Insanemoondoggie

I use to be Brand loyal ,and fond of Saito`s , but as I get a few more yr`s of flying under my belt , I find chosing my engine , is decided on by the weight and CG of the plane I`m building. If the plane is nose heavy , I would go with the saito, if tail heavy, I would got with the OS 1.20 . I have several different brands of 4 strokes to choose from ,and pick the engine , that helps me balance the plane with the lest amount of weight.
Also have a couple of old Italain SuperTigre 90`s I picked up on Ebay . Went thru them, bearings and new ring , cleaned carbs . One`s in a 4 Star .60 and ones in a Skybolt .60 , lots of power and they have performed flawlessly. So I can not sell the 2 strokes short either. Sry , I probably just confused you more . lol Good luck and have fun.

playntraffic

Either the YS110 or the OS 120AX will work well in your YAK. The YS will run well on 15% nitro. The YS has a better midrange transition, the throttle response is instant. With the OS the powerband is more in the upper to high rpm range.
Both engines will pull a 9lb plane like crazy. I have a YS 110S on a 9lb extra 260. The plane hovers at a little less than mid throttle and takes off vertical like a rocket. If you do the research on setting up the needles and regulator than the YS hardly ever needs adjustment. I was running 30% nitro for a while, 10,000rpm on a 16x6APC. I have changed to 20/20 fuel and the RPM dropped to 9800. I could probably run on 15% and still have gobs of power for my size plane.

The quality of the Saito and OS FS are nice, but they just don't have the same power as the other two.

ChuckW

What it will probably boil down to is just making whatever you pick work for you. Everything you've mentioned will fly the plane very well. You may be thinking about a first 4-stroke but it won't likely be the last. You can always try somethign else down the road.

As for the OS 4-strokes, several people have commented that my .91 is not enough for my TF Mustang how the Saitos are supposedly much better, etc. It has a good prop and is tuned right however and most change their opinion after seeing it in the air. It hauls the plane around very nicely.

Saito, OS, Thunder tiger, it'll all work well.

Jetdesign

My Feedback: (8)

Thanks. I definitely lack the experience of making things work which is why I hesitate after seeing my plane with a Saito 125, which probably has a shallow pitched prop and a super aft CG. I have no idea how much things will change with CG and prop selection. I have seen a video of the plane with the YS, and it totally blows me away! I just found out it's with 20% nitro, so it shouldn't perform too much differently if I run 15%.

So another question: other than the new FSa series by OS, do all four strokes have a port on the back plate? What is this for? Can it be branched off and used for a perry pump?

ChuckW

Most have a port somewhere on the crankcase for venting oil and blow-by. Sometimes these are just vented to atmosphere and on some engines they are ran back into the intake. I don't have a lot of experience with Perry Pumps but if they work of crankcase pressure I suppose it would work fine. someone else might have more input on that though.

MinnFlyer

My Feedback: (4)

The only Perry Pump that I have used works on engine vibration and no crankcase pressure is needed.

That being said, I've never needed to use a pump - I've TRIED them, but found them unnecessary

Jetdesign

My Feedback: (8)

Yeah there are two syles - one runs off case pressure, one off vibration. I can't say one is 'needed' in my application. However, pumps allow you to tune to max rpm and not richen the few hundred RPM necessary to prevent leaning out in the air. If I don't get the YS, I"m sure I'll want to suck as much power out of the engine as I can, and I already have an extra (case pressure) pump.

This is the difference between the pumped and non-pumped versions of the 120fs in power rating, and it makes sense.

MinnFlyer

My Feedback: (4)

As you know, very few people have anything bad to say about OS. However, the one negative comment I HAVE heard is that there are problems with the pumped versions of their Surpass line.

Next up - if you want to squeeze every ounce of power out of your engines, stick to 2-strokes. 4-strokes like to run at a much lower RPM and trying to squeeze "The Most" out of them will often end up with you buying a new engine.

If you're really that power-crazy, get the YS.

Jetdesign

My Feedback: (8)

Just want to thank everyone for their help. Being in school, it's (hopefully) going to be a while before I get another engine or make another purchase this big. This forum and others have been a big help.

Minn, you're absolutely right, and I think the YS is the engine for me. Really what I want is a four stroke with performance like my 120AX, with more mid range power and less of a need for throttle range. I got spoiled with my AX pretty quickly, and don't want to give up anything without return.

Since it should be a while before I buy another engine (like the OS 120 four stroke for the Super Stearman I want next) I can't let $20 or $30 influence me as much as it was. Better to get what I want and be happy with it. YS engines just went up in price this week, but it's just something I'll have to deal with.

ChuckW

That Stearman is a beautiful airplane. A few guys at our field have them and I keep telling myself I need to get one. there is just something about a classic bipe. I've seen the plane fly with a 1.20 and it is great. From what I understand though, it needs quite a bit of lead in the nose to balance so a lot of guys are using small gassers since the extra weight of the engine makes it easier to balance the plane.

Jetdesign

My Feedback: (8)

Yeah, the instructions talk about 19oz of lead, and it comes with a special box for all the lead. I can think of much more interesting things to stick in there other than lead though Maybe it would be a nice first gasser, too. I like the simplicity of one fuel, one fueling system, etc. but maybe that will change.

I don't know what it is about big classic planes and OS four strokes. I have yet to have either, and it already seem like a perfect combination!

That Stearman is really sweet looking....

Gray Beard

My Feedback: (-1)

I like pumps!! I like mounting my fuel tank right over the CG and a pumper allows me to do this. With a pumper the fuel is regulated so there aren't any lean or rich moments due to the the attitude of the plane. The only problem I have had is getting one small little part for my regulator from OS, a diaphram. There is one in a YS too and every couple of years it needs to be replaced but they are cheap and I usually have them on hand. The YS is the better engine, it runs very well on 15%, I have even run them on 5%. There is no difference between the engines when you tune one, a high and low end needle. That big brass screw that freaks everyone out is just the pressure regulator and for the most part you never have to touch it. I have found my YS engines less of a problem then the Saitos but none of them are ever very cranky. I am wondering about the 9 pounds though. The YS has the beans for it but I'm not sure how well it would do with the 3-D part. 9 pounds is a bit heavy for it. Joe, I will have to weigh my Mid West Hots for you and I could let you know. It's a heavy little plane and my 1.10 YS can pull it straight up out of a hover, I can't remember but I think it's about 7 pounds, maybe more?? I'll let you know. I did use a YS 1.40 sport on a Goldburg Extra, that's a heavy 68 incher, OH MY!!!!! Wish it was my engine!!!