1wrangler

My Feedback: (1)

Has anyone here flown a Sig four star 60 with an o.s. .91 fx engine? I am currently using an o.s. .61fx and it runs/flies great but I've always wanted an airplane with unlimited verticle performance (which the .61 can't do on this airplane). If you have experience with this set up please let me know if the .91fx produces enough thrust for this.

Thanks in advance

MetallicaJunkie

i flew one with a super tigre 90 and 14x6 prop...pretty much unlimited vert, but not by much from what i remember...the 91fx should give you what you are looking for...prop it right

airbusdrvr

And be sure to buy some extra fuel for the motor. It is thirsty.

Gray Beard

My Feedback: (-1)

I used the SK .91 and it was great. Maybe the OS drinks more fuel then the SK?? I didn't even bother installing a bigger tank and flight times were about the same.

w8ye

My Feedback: (16)

The plane is forgiving as to the engine used.

wjcalhoun

My 4*60s have both been powered by OS .75AX; best prop I have found is APC 13x6. Vertical is certainly not unlimited, but the plane is spirited.

LargeScale88

One thing I was thinking is can the airplane handle that big of engine? Obviously it can sense other people have flown. I would say its a good match for it, especially sense you want unlimited vertical performance...

w8ye

My Feedback: (16)

A OS 91FX will fit in a Four Star 60 like the plane was intended for that engine

In fact, unless you mount the engine forward, you may have to add some nose weight to the front to get it to balance

Gray Beard

My Feedback: (-1)

Most of them I have built, I use them to teach building with, I have used a four stroke. Most of them the owners have chosen the Saito 100. It fits perfect and is a great choice. The one i finished last week the owner decided on the OS .61. Due to very high winds we haven't maidened the plane yet, with luck, sometime this week? This one is the first 4* I have ever built stock, even stock controls. With the battery up front under the tank the CG came out perfect?? A big surprise to me. The 4* 60 has plenty of room up front for a bunch of engine choices and doesn't seem to care a lot what you stick in it for power. One thing I noticed right away, that wing is huge if you don't cut out some bays!!! This should be a fun maiden!! I'm guessing the term floater is going to pop up a lot??

w8ye

My Feedback: (16)

I had a Four Star 60 with a OS 91 Surpass. Fit the plane perfect, Balanced perfect, Had plenty of power. Still had plenty of float.

I have seen them with OS 70 Surpass engines as well as Saito 72 & 80 engines. They flew fine also.

jamesc43

My Feedback: (2)

One of the guys at our flying field has a OS FS 91 mounted in his. He also has the OS mount for the OS FS 91. His balances
with the battery unfer the tank. He has good performance and it floats on landing. We upgraded his prop to a 14X8 MAS and
it now had very good performance on the upper RPM range. I think he had it under proped before and wasn't getting the full
pull out of the engine.

I picked up what I believe is a 4 star 60 used. I think it was originally a ARF but it never had an engine mounted in it nor had
it ever flown. I mounted OS FS 91 engine mount. I also mounted a YS 91-FZ. It has a 14X8 MAS prop also. I mounted the battery
under the tank to get the CG where it needed to be in stock form. I couldn't bring myself to mount my OS 91 FX.

The OS 91 FX should fit it like a glove. It will have excelent power. The weight shouldn't be a problem either. The plane may be
a little (a lot) overpowered but nothing out of the ordinary for a 4 Star.

Ed_Moorman

My Feedback: (1)

I have had 2 Sig 4-Star 60s. One had an OS .91FX and the other a Magnum .91 XLS. Both of mine were modified to look like a Kawasaki Tony with the gear in the wing. Both flew extremely well with a 14-6 prop.

I did order the long Ultra Thrust muffler. With this on either plane, it would climb like a rocket as far as I could see. A Jett muffler works as well. Be sure to call them and tell them what you want and use their recommended prop size. These tuned mufflers have an rpm sweet spot where you get the boost and you need to use the prop that lets the engine turn in this range.

1wrangler

My Feedback: (1)

Thanks for the info guys, now I just need to find a good used one at a reasonable price   and I'll let you all know what I think of it.

1wrangler

1wrangler

My Feedback: (1)

Well I picked up an os .91fx for a good price and put a 14x6 apc prop on it. Took it up today after some breaking in of the newer engine and found it provided the unlimited vertical I was looking for   It's not real fast on vertical climb but it does it, lots of fun!

w8ye

My Feedback: (16)

You have a good combination.

May you have many flights

Gray Beard

My Feedback: (-1)

And after doing the maiden on the stock one we built all I can say is it flys very well for someone on there second plane or someone that just wants to do mild stunt flying. Not to bad and i could use up a lot of sky doing big giant loops, that vertical power the OP was looking for wasn't there but it isn't a real bad choice. I like a lot more power for my own flying but it wasn't my plane. It works very well for the proud owner and it was his first build from a kit.