alqwad

My Feedback: (12)

I have a Magnum 91 in mine on a 13x8 prop. It flies nice and stable at all speeds, especially wide open. I'm sure the YS that you have (the 91) would be a bit more powerful than my setup and again, I love mine. I tried a 14x6, but the 13x8 on that engine made the difference for sure. Best of luck. You'll love the plane. Take care. BTW, mine did balance way tail heavy. I ended up putting a 1100 mah RX pack AND a "C" cell battery for my onboard glow up on the engine box/firewall. Balanced out great and flies very nicely.

-RME

Texas1

My Feedback: (5)

Anyone found a good covering match for for repairs? Have a small cross wind mishap on a dead stick landing. Need to make a little repair.

alqwad

My Feedback: (12)

I read in a thread, maybe this one, that someone called Tower and was told to use Monokote... Hope that helps.

proulxlaw

My Feedback: (3)

Texas1:

Have tried talking to Tower? I would be willing to bet that they would replace your plane.

I always use fiberglass cloth with epoxy on firewalls of ARF's even on the smaller ones. The glue that gets used in the factories is not the best and to make matters worse in some cases it's not very well applied.

Here's some of the crap that's going into mine which should be at my door around the 20th. I paid Tower $139.00 shipped. In the pic is a YS 91 with a SU31 shaped spinner, a Futaba high tourque mg servo for elevator, a Russky looking pilot and a 20 oz. Kavan tank that is made to withstand the pressure generated by YS motors.

Texas1

My Feedback: (5)

No, did not talk to Tower about the first sukhoi. I have rebuilt the firewall and replaced it. You cannot tell it ever exploded in air. She sets there in case I dork the new one to bad. Which, as I said before, I broke the nose in a dead stick landing in wind I should not have been flying in. Hoping to find a better color match than monokote, but used it. Luckily the repair spots were small so it not that noticeable.

proulxlaw

My Feedback: (3)

I agree that the construction of the firewall on this plane is a little cheesy and definitely requires strengthening. I used fiberglass cloth and lots of epoxy on the inside and outside of the engine box.

I decided to use a YS 110 and an aluminum (Saito) engine mount. The build is coming along fine. I'll post pics as time permits. I also used Robart scale wheels and I decided not to use the wheel pants. They are usually nothing but problems. If you have a tough landing the wheel pants will go right through the wing creating a nice big hole in the covering on the wing and if you look at other SU31's, most don't have any.

Kostas1

Anyone who uses the OS 91FX as a powerplant?
Impressions?

bluestratos

I am using the OS91 FX.. Fits nicely and has plenty of power, nearly unlimited Vertical. Very fast. And of course you cant beat OS's quality and ease of tuning.

Regards,
Randy

proulxlaw

My Feedback: (3)

I used a YS 91. I may throw in a YS 110 depending on performance.

Kostas1

With the OS 91FX you don't have unlimited vertical?
Why?
What prop do you use and what fuel.
When Summer comes i will start breaking in my 91FX for my Corsair,using an APC 14x6!

bluestratos

Nearly unlimited.. lol.. and yes, I may have to prop differently but I am so happy with the over all package I dont want to change props till I need too. Right now I can take off and pull straight up with no difficulty but by the time she gets way up there the sticks get a bit mushy. The engine only has about 1 hour on it so it may get better yet.

Best regards,
Randy

Kostas1

Please,
can you tell me what prop do you use?
Also,
i test run my 91FX today and i had difficulty on turning the high speed needle.
I applied 2 drops of Hobbico after run oil but the problem is there again.
[:@]
But,
in addition to that the transition in excellent,of course a bit rich idle but with 3 turns out of fully closed position........

proulxlaw

My Feedback: (3)

My plane has unlimited vertical with the YS 110 that I installed. I used a 15/8 Graupner and 30% heli fuel.

ghost-RCU

My Feedback: (10)

I maidened mine today. I'm running a O.S 91 Surpass on it. This is a nice flying plane & is very easy to land on the mains. She really likes to glide. Eventhough I have yet to really ring her out, without question it' a great value for 150.00 Love this plane.

PopPhil

My Feedback: (8)

Great plane! 1st flight yesterday " WOW " one click of up, a little nose heavy. Its like everyone has been saying a really nice plane to fly. Two more flights today, moved cg back a 1/4 in, still a little nose heavy.response is getting better. I'm running a OS 90 surpass 4S with 14/6 prop "goes vert" . Love this plane. Yeah the covering leaves something to be desired, but the price is right.

alqwad

My Feedback: (12)

Sounds good. If you get a chance, try a 13x8 on for size. Made a ton of difference for me. I'm running a 91 magnum, so I'm not sure if runs quite as strong as your OS. Good luck. [&:]

Kman1971

What were you running for a prop before changing to that 13x8?...i am runnning a 15x6 on mine...that cowl is so big just seems you wouldnt get much pull on that small a prop. Kieth

alqwad

My Feedback: (12)

I'm runnning a Magnum 91 four stroke on 15% cool power. I was using a 14x6 and the performance was a bit sluggish. I switched to a 13x8 and it was like a completely different airplane. Now, it's very fast and has much better vertical performance. Good luck.

Kman1971

thanku for the reply..i am running an os 91 4 stroke.i am thinking about trying that prop for the heck of it..sounds like you are happy with that combo...wonder if altitude will be a factor since i am at higher alt than you..well either way thanks again Kieth

proulxlaw

My Feedback: (3)

If you want the best combo for this plane try it with a YS 1.10. This is how I set mine up and this thing really rips with this motor.

sherman89

I flew a SU-31 yesterday for the first time with an OS.61 and a 13x6 prop at the power end, the plane flew off the board with 3 oz added to the nose. Surprising, the .61 did a good job, not exactly 3-d but acceptable. Has any one tryed a 15x4w on the same setup? I think a OS 91 2-c would make this plane scream, I don't have one, may have to put it on the wish list. Has the OS.91 had vibration problems since it's changes last year?

sherman89

I tryed a graupner 12x6 today on the OS .61, it slowed down on the down line which was nice but only held it's own on the up line, no increase. A touch more right rudder was needed near the top of the climb which did hold on slightly longer than the 13x6 2 blade. The 12x6 held the rpm back at level flight which of course held the speed down. The plane flys well, but the covering is a different kettle of fish. Very poor quality, in this day of ARF's the covering is very poor at best, Hobbico is a good company, I can't believe they stay with this covering, it's got to be costing sales!

bluestratos

I put the new 91 OS in mine, but I have not flown it yet. It fits perfectly and I use one in my Goldberg Chipmunk so I have experience in a simular sized airframe. The Chipmunk loves the 91, fast, great vertical. Not 3D type power but the plane is not 3D friendly anyways, lol..
The 91 is such reliable, easy starting engine.. it likes a bit of prime on the first start but after that easy start every time.
The long landing gear on the Sukhoi makes propping easy, lots of clearance for any prop this engine can handle.
Best regards,
Randy

proulxlaw

My Feedback: (3)

Put a YS 1.10 in it and you'll be in heaven.

epoxy123

Anyone know what size pilot figure goes with this Sukhoi?