aaronarvig

I feel I have finally gotten good enough flying my Sig Kadet LT 40 that I am ready to step up to a low winger. I bought the four star 60 and am in the process of building it but I am having a difficult time deciding what motor to put in it. I either want the OS 91 Surpass II or the OS 75 AX. Does anyone have experience with either or both and can tell me which one would be better suited to this airplane? Also, I read a lot of negative things about four-strokes without any support as to what they are talking about. For instance, people say the maintenance on a four stroke is more...what are they talking about? What kind of maintenance? Thanks in advance for your answers.

cruzomatic

My Feedback: (17)

Whomever said negative things about 4 stroke engines didn't really know what they were talking about. 4 strokers are prime in r/c. I have a TT.91FS in my 4*60. I'd recommend the 4 stroke simply for the power (ability to swing a larger prop with the added torque) sound and little fuel it uses. Choice is yours. As far as maintenance, I've been flying over 7 years and own about 8 four strokes maintenance is next to nothing. Every now and then the valves may need to be adjusted. Again, "may" need to be adjusted.

Good luck.

Insanemoondoggie

I just started to build mine a couple of days ago and kicked around what engine to use. From doing some research , the OS .91 seems to be the choice , and would make a nice combo. The .75 AX would work just as well and may be a little stronger than the .91 but you`ll have more clean up. Both are good engines.
Maint, on four strokes is really not a big deal . Set the valves once a year . Some say they are harder to tune ,than a 2 stroke. I dont think their harder , just different.

If I had a Saito 1.00 , thats what I would go with , or the O.S .91 but don`t sell the OS .75 short , it`s a great engine .

Aquired a worn out Itailan ST .90 in a trade . Rebuilt it with new bearings, sleeve and ring , and the thing runs so well I`m going to stick that on my 4* .60 . Has a crunchy sound to it .
My 4* .40 with a Saito .56 would knife edge with lots of throttle and would run out of vertical or power at the top of loops , so I figured , what the heck , more power on the .60 wont hurt.

Missileman

I have to agree, the myth about 4 strokes is really false. I have grown to like my 4 strokes better than my 2 strokes.
I don't see what would be harder about tuning and IMO 4 strokes are better on fuel and for me seem to run smoother.
If you want to save a few bucks Magnum 4 strokes are just as good as OS or Saito, and yes I do own and fly all 3 brands.

Fastsky

If you want great performance for a 2 stroke check out the Tower Hobbies 75 engine. Its an easy to adjust strong running engine. This is one one case where the quality and performance far exceeds the low selling price. The other engines are top quality no question, but cost twice the price for the 2 stroke or 2 1/2 times extra $$ for the 4 stroke. You have to ask yourself if the slight extra power that you "may" get worth that to you? [8D]

chashint

All of the engines you are considering are very nice engines.
The only thing wrong with any of the two stroke engines is that they sound like two strokes.
The OS 91 four stroke is especially user friendly and it does not sound like a two stroke.
Just follow the instructions that come in the box to break it in (you will be flying it on the third tank of fuel).
Use a tachometer to set the high speed needle valve.
Don't adjust anything on it except for the needle valves unless there is a darn good reason to do so.
I have never understood why someone would adjust the valves on a perfectly good running engine.

w8ye

My Feedback: (16)

Though the Four star 60 begs for a four stroke, they are actually very versatile and function very well with most any two stroke or four stroke engine from 60 up including the newly designed lightweight 120's

donkey doctor

Hello; Another vote for the four stroke engine. The 4 star 60 builds a bit tail heavy, so a heavy four stroke will work great. I started with a Saito 80, but I had to add weight to the firewall, and I had an old OS 90 FS that was heavier that I put in there. It worked so well I left it in there. I think the surpass 91 is a little lighter then the FS90. You'll find that the four stroke flies at part throttle beter then a two stroke can, and if you fly like me, you'll be flying at part throttle a lot more then full throttle.

Appfan

Add me to the list of 4 stroke users as well. I'm in the middle of my 4*60 build, and found a good deal on a Saito 82. I had originally planned on a 91, but a club member had an essentially brand new 82 "on sale".

Let us know how your build goes. I'm in the final phases of moving into my new workshop, so my build is on hold for now....

aaronarvig

Thanks for the advice everyone. I took the plunge and ordered an OS 91 Surpass II!! Tower has a $25 coupon on anything over $199 and OS has a merchandise certificate with new motors for $30 bucks. Not a bad deal!! I let you all know how the build goes!

w8ye

My Feedback: (16)

used a OS 91 Surpass in my Four Star 60. It was nice until I lost it close-in in the sun one day.

rceric

I have two Four Star 60's with 4 strokes in them. One with a 70 that is terrific and the other with the 91. The 91 sounds incredible and the power is a perfect match! You will be very happy with your choice.

Enjoy!

cruzomatic

My Feedback: (17)

Atta boy. You'll love that engine in your four star!!

CGRetired

My Feedback: (1)

I have a Goldberg Protege. The original engine recommendation for that plane was an OS 55 AX but I couldn't get one at the time so I opted for the OS 75 AX. Absolutely no regrets with that engine. It's a power house and starts and runs great, right out of the box. This engine pulls that Protege, which, by the way, is as large as the Four Star 60 and the Goldberg Tiger 60, like a much larger engine.

I highly recommend that.

As far as four strokes is concerned, the only reason I didn't opt for one is that they were a bit more expensive and I was a bit unfamiliar with them. I have to ditto all of the above in support of them.

I have three OS 1.20 AX's and love them and the 75 runs as well as those do. But, if you prefer four strokes, I can't think of any negatives that may change your mind. They are fine engines. Lots of torque, and sound realistic too.

CGr.

rctrax

I have 8 four strokes and one two stroke and its still in the box. Four strokers have no issues and are very usre friendly. Mine hand starts first flip every time after prime.Never touch the needle valve from year to year. I had one that hung unused in the shop for 2 or 3 years and started on the first flip and flew great without even touching the needle valve.

philsmein

What an awesome plane!!! Mine is strapped with a Saito 82 FA Fourstroke. If you hear a fourstroke engine you will buy one. The 2 strokes suck after you hear the four stroke run. A 2 stroke is like watching your favorite movie, a fourstroke is like watching your favorite movie with surround sound. Nice choice!!

Rene3706

I have built four 4* 60's and highly recommend a 91 four stroke. I have put both OS 91's and Magnum 91's, the only difference is price, the magnum is about $100 less. I am not a speedster and the plane flys well at 2/3 power, I would however not go with anything less. You will really enjoy this combo, it is a very easy plane to fly and lands as slow as you want. Some people complain that is has a tendany to float. I put a 14X6 prop and this slow it down nicely.
Good Luck.

hungryandbroke

Only downfall on a 4 stroke is the cost of repair. I put a 91 surpass into the ground upon takeoff 5 feet off the ground and the cost to repair it was $175 in parts alone! Thank God Tower Hobbies fixed it for me for FREE.... They said....Courtesy of Customer Service.

Other than the cost for repairs, you can't beat a 4 stroke.

I wouldn't recommend any 4 strokes for beginners if money is an issue.

Edit....

Where as I also put a super tigre .61 2 stroke into the ground at full speed straight down and only ended up replacing the propellar and the needle valve. About $20

rctrax

There is no to compare one engine's damage from a crash to another. It simply could be hitting harder or from different angles. Even the hardness of the ground is a variable.

Insanemoondoggie

Just finished my 4* , Need to trim the canopy and decide on what kind of stiping I`m going with.
Has an old SuperTiger G90 that I put a new ring , sleeve and bearings in. Runs really nice.

Rene3706

Looks really nice. You will have a blast flying it. I noticed in the picture that shows a close up of the engine that the engine compartment does not look like it was fuel proofed. If not, you can just just expoy glue thinnned a little, but it does need something or the raw wood will absorb the fuel.
I have just finished covering the fuselage of mine (#4) and hope to get the wings covered in the next couple of weeks.
Again, good job.

Insanemoondoggie

It is fuel proofed with 30 min epoxy , at the firewall and fuel tank area. And the wing area has flat clear lustre coat applied .