airroy

My Feedback: (7)

I am starting to look forward toward building a .60 flier. Probably a Sig 4Star. I am thinking about putting a 4 stroke in it rather than a two stroke. Something around a .91 or so. Herein lays my question. There are several manufacturers of 4 strokes and within most of the manufacturers there are a couple different choices of engine at the same (close) displacement. To name a few, OS, Saito, YS, Thunder Tiger, etc (?). Then there is ringed vs. non-ringed. I can't say cost is not an issue, but it will not be the main issue in my decision process.

Any info regarding comparisons of any/all 4 stroke fuel engines around the .91 size will be greatly appreciated.

Thanks,

Roy

TNRabbit

Saito is probably the best all-around 4 stroke. Lightweight and dependable with good power-to-weight ratio. YS are excellent but way too much power for this application and they are fuel HOGS (suck it down like a two-stroke).

barto

YS are not only big drinkers they also consume very expensive fuel, since they can't run good on anything less than 30%.
I agree that saito are pretty much the best of the bunch I think, quite a bit cheaper than OS and I haven't heard any complaints about them.

rc-sport

My Feedback: (12)

Either Saito or OS would be a good starter 4 stroke.

MinnFlyer

My Feedback: (4)

Barto, I have a bridge in Brooklyn I'd like to sell you.

If my YS drinks more than any of my other 4-strokes, I sure haven't noticed it. And All I ever use is 15% Cool Power.

Still, I wouldn't put one in a 4*, That's way more than it needs.

An OS 91 surpass would be ideal.

Saito 91 - 100 would be fine too.

airroy

My Feedback: (7)

Thanks for these replies. What do any of you think about the Magnum or TT comparable size 4strokes?

Ed_Moorman

My Feedback: (1)

I can speak for Saito & Magnum .91s since I own both.
First compare the weight to a .91 2-stroke, Magnum XLS or OS FX (I have and have weighed both of these)

.91 2-stroke 25.5 ounces

Saito .91 20.5 oz. (Digital scale weight)
Magnum .91 22.5 oz. (Digital scale weight)

I would think the OS would be the same as the Magnum, since the Mag is a copy. From what I read, the Thunder Tiger is over 26 ounces, more than the 2-strokes.

Power:

My Saito and Mag are about the same. I would put a friend's OS in the same area. It is said on RCU that the TT is more powerful than either of these.

Power-to-weight goes to the Saito. Ease of break-in and set-up goes to the OS. Price goes to the Magnum. I don't like heavy engines so I haven't considered the TT.

Some people are going to tell you they love the YS, and I'm sure they do. But, the regular fliers who I have seem with them have messed with them a lot. They run YS 20-20 fuel and they use a special after engine run oil. They do have lots of power and you can run the tank anywhere, but they are heavier and I am not willing to put up with the special requirements.

Check what guys are flying at your field and see how they run. You pays your money and takes your choice. The 2 brands I have and the OSs do run well. Any would be a good choice.

If you are used to ABC 2-strokes, you will need to do a good break-in on a ringed 4-stroke. It is not unusual for them to need 2 and up to 3 gallons before they really run great. I'm sure someone is going to tell you to put it in a plane and go fly, but check with the guys who fly 4-strokes a lot and who love them and they'll tell you they ran them some on the bench and then ran them rich in the air and it takes a couple of gallons for them to really run well.

MHall

My Feedback: (7)

The Saito or OS are your best bet. Avoid the "cheaper" brands, you get what you pay for. The YS's are great engines but are way too much for that type of airframe. A well tuned OS or Saito will give you years of trouble free flying. Make sure you run a good brand / grade of fuel too.[8D]

Spaceclam

ys engines are competition engines. they provide the power of a much larger engine while weighing less. however, they are heavier than non-supercharged 4 strokes of their same displacement so if you just want a good 91 or 120 to cruise around with, than the ys is definatly not the best choice for you. that is where OS and Saito shine. meanshile if you want a good engine for a 9-10 lbs 3d plane or a warbird or pattern plane, the ys engines are ideal for your application. considering you are using a 4* 60, get the os or saito. they are both exceptional 4 strokes. OS makes a pumped version of their surpass II in both the 91 size and 1.20 size. those are great motors as well. the only reason i sold mine was becuase i wanted a ys for my new plane (a 3d plane) and so far it has been just an exceptional engine, but it not the best engine for a 4* 60.

old propnut

I have been flying 4 Star with a thunder tiger 91 4 stroke for about 3 years now, a real good combo.
If you build the 4 Star, clip one bay off the wings, rolls faster.knife edges great and will do most of what you ask and will still slow up for pretty 3 point landings. And o yes add 1" to the rudder.

airroy

My Feedback: (7)

Has anyone ever had problems getting parts for a Saito engine. Looks like Tower has most parts you could ever need for various OS engines.

Richard L.

My Feedback: (24)

Wrong. Do you even own a YS?

All my YS four strokes run and idle like clocks on YS 20/20 fuel. My new 63 even runs and idles like a champ on 15% fuel: [link=http://www.whitetyphoon.com/rc/ys63s/idle.mpg]YS 63S Idling[/link] (mpeg)

A video showing the awesome sound and power of a YS 91FZ: [link=http://www.whitetyphoon.com/rc/gsp_spit_show_pass.mpg]Spit Show Pass[/link] (mpeg)

A video showing a new YS 110 idling after only a couple of tanks on the bench: [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/SlowIdle.mpg]YS 110FZ Idling[/link] (mpeg)

A video showing the awesome sound and power from the same YS 110: [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/HighSpeedPass03.mpg]Corsair High Speed Pass[/link] (mpeg)

Fuel consumption on these engines are not that bad, and after run oil is not needed. After hundreds of flights, I have yet to experience a single problem or deadstick. I agree with others that a YS is way too much power for the 4 Star.

airroy

My Feedback: (7)

Thanks for the info. Good stuff. Thanks for the video clips! What a beautiful Corsair!! By the way, what is the size,wingspan of that Corsair ? Is it an ARF or a kit?

Richard L.

My Feedback: (24)

Thanks. That's a Hangar 9 Corsair ARF with a 65.25" wingspan. It's a beautiful flyer.

Sport_Pilot

I have the TT .91 also, it is a very good engine, strong and durable. Unfortunately support and service is lacking. You can get parts if you service it youself, but sometimes it takes a while to get them.

airroy

My Feedback: (7)

Warbird,

What prop are you running on that?

Richard L.

My Feedback: (24)

That's a Bolly 16.5 x 8 carbon fiber 2-blade prop.

davidmor

I have an Enya .90 and Magnum .91 and both a very good engines. The Enya has decent power, is very reliable, and starts very easily. The Magnum is a little lighter, has more power, is also very reliable, and starts almost as easily as my Enya. I would not hesitate to buy another of both of these engines. The Magnum is pretty much a direct copy of the OS .91 and costs quite a bit less. I couldn't justify the price difference when I was buying the Magnum.

Richard L.

My Feedback: (24)

Here are some more video clips of the same H9 Corsair if you are interested:

* [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/TakeOff01.mpg]Take Off[/link]
* [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/SlowPass.mpg]Slow Pass[/link]
* [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/ScaleRoll.mpg]Scale Roll[/link]
* [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/BigLoop01.mpg]Big Loop #1[/link]
* [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/BigLoop02.mpg]Big Loop #2[/link]
* [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/SplitS02.mpg]Split S #1[/link]
* [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/SplitS03.mpg]Split S #2[/link]
* [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/HighSpeedPass02.mpg]High Speed Pass[/link]
* [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/InvertedPass.mpg]Inverted Pass[/link]
* [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/Landing01.mpg]Landing[/link]

airroy

My Feedback: (7)

Thanks very much to everyone that took their time ( could have been flyin ! ) to respond to my question. I learned a lot.

nemesis4u

My Feedback: (77)

Is the Magnum better than the TT 91 Fourstroke????? and what fuel is recommended....Lastly what 3 blade prop...?? 13x7?? I need two very reliable 4Strokes for a Twin Engine 80" OV-10 Bronco...any suggestions are much appreciated...I dont want to spend the big $$$$$ for YS...

Rodney

As an owner and regular user of many 4 strokes; I have Enya, OS, Magnum and Saitos. Of all these (and all work well and give good performance) the Magnum wins hands down on value per unit dollar. It IMHO gives identical performance of the OS's and life span so far has been very good. I'd highly recommend the Magnum 4 stokes for the biginner especially as they are so easy to break in and use.

Sport_Pilot

The TT is heaver by about 2 ounces, but more powerfull than the Magnum. I don't know how this will balance on the OV-10 but if overpowering a smaller model I would recommend a Saito, else the TT may fit the bill. If service is a biggy then the Magnum and OS may be a better choice.

I own a TT .91 and it is very powerfull and gets well over 10,000 RPM with a 14-6 prop and 15% nitro. With 25% nitro it would peak at over 10,600 RPM, but I richen it up to 10,300. Never owned a Magnum but I had an OS .91 and the best I ever saw from it was 9,800. The Magnum is a near clone of the OS .91.

I would suggest a 13-6 for a three bladed prop, that is if someone makes that. The biggest problem with three blade props is a lack of sizes.

Sport Flyer

My Feedback: (10)

My trusty old Enya 90 FS turns a MAS 13x8 3 blade with great authority. RPM set for flying was in the mid 9k range - 9.4 to 9.6 depending on the day, how old my fuel was getting etc. The Enya is probably the best for longevity, however they no longer produce the 90 so the only way you can get one is used. Mine is currently in its 3rd airframe, now swinging a 15x6 on the nose of a Great Planes Fokker DR1. As for the Magnums, TT and ASP 4 strokes, they all sure bare an amazing similarity to the OS, which IMHO speaks volumes for the engine being copied.

Hobbsy

My Feedback: (102)

http://www.zingerpropeller.com/3_bladed_Propeller.htm

Left column near bottom of page.